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  1. Skeletal Muscle Oxygen Saturation (StO2 Measured by Near-Infrared Spectroscopy in the Critically Ill Patients

    Directory of Open Access Journals (Sweden)

    J. Mesquida

    2013-01-01

    Full Text Available According to current critical care management guidelines, the overall hemodynamic optimization process seeks to restore macrocirculatory oxygenation, pressure, and flow variables. However, there is increasing evidence demonstrating that, despite normalization of these global parameters, microcirculatory and regional perfusion alterations might occur, and persistence of these alterations has been associated with worse prognosis. Such observations have led to great interest in testing new technologies capable of evaluating the microcirculation. Near-infrared spectroscopy (NIRS measures tissue oxygen saturation (StO2 and has been proposed as a noninvasive system for monitoring regional circulation. The present review aims to summarize the existing evidence on NIRS and its potential clinical utility in different scenarios of critically ill patients.

  2. Diffuse reflectance spectroscopy for the measurement of tissue oxygen saturation

    International Nuclear Information System (INIS)

    Sircan-Kucuksayan, A; Canpolat, M; Uyuklu, M

    2015-01-01

    Tissue oxygen saturation (StO 2 ) is a useful parameter for medical applications. A spectroscopic method has been developed to detect pathologic tissues, due to a lack of normal blood circulation, by measuring StO 2 . In this study, human blood samples with different levels of oxygen saturation have been prepared and spectra were acquired using an optical fiber probe to investigate the correlation between the oxygen saturation levels and the spectra. A linear correlation between the oxygen saturation and ratio of the intensities (760 nm to 790 nm) of the spectra acquired from blood samples has been found. In a validation study, oxygen saturations of the blood samples were estimated from the spectroscopic measurements with an error of 2.9%. It has also been shown that the linear dependence between the ratio and the oxygen saturation of the blood samples was valid for the blood samples with different hematocrits. Spectra were acquired from the forearms of 30 healthy volunteers to estimate StO 2 prior to, at the beginning of, after 2 min, and at the release of total vascular occlusion. The average StO 2 of a forearm before and after the two minutes occlusion was significantly different. The results suggested that optical reflectance spectroscopy is a sensitive method to estimate the StO 2 levels of human tissue. The technique developed to measure StO 2 has potential to detect ischemia in real time. (paper)

  3. Near-infrared spectroscopy during stagnant ischemia estimates central venous oxygen saturation and mixed venous oxygen saturation discrepancy in patients with severe left heart failure and additional sepsis/septic shock

    OpenAIRE

    Mo?ina, Hugo; Podbregar, Matej

    2010-01-01

    Introduction Discrepancies of 5-24% between superior vena cava oxygen saturation (ScvO2) and mixed venous oxygen saturation (SvO2) have been reported in patients with severe heart failure. Thenar muscle tissue oxygenation (StO2) measured with near-infrared spectroscopy (NIRS) during arterial occlusion testing decreases slower in sepsis/septic shock patients (lower StO2 deoxygenation rate). The StO2 deoxygenation rate is influenced by dobutamine. The aim of this study was to determine the rela...

  4. Investigation of spatial resolution dependent variability in transcutaneous oxygen saturation using point spectroscopy system

    Science.gov (United States)

    Philimon, Sheena P.; Huong, Audrey K. C.; Ngu, Xavier T. I.

    2017-08-01

    This paper aims to investigate the variation in one’s percent mean transcutaneous oxygen saturation (StO2) with differences in spatial resolution of data. This work required the knowledge of extinction coefficient of hemoglobin derivatives in the wavelength range of 520 - 600 nm to solve for the StO2 value via an iterative fitting procedure. A pilot study was conducted on three healthy subjects with spectroscopic data collected from their right index finger at different arbitrarily selected distances. The StO2 value estimated by Extended Modified Lambert Beer (EMLB) model revealed a higher mean StO2 of 91.1 ± 1.3% at a proximity distance of 30 mm compared to 60.83 ± 2.8% at 200 mm. The results showed a high correlation between data spatial resolution and StO2 value, and revealed a decrease in StO2 value as the sampling distance increased. The preliminary findings from this study contribute to the knowledge of the appropriate distance range for consistent and high repeatability measurement of skin oxygenation.

  5. Assessment of muscle tissue oxygen saturation after out-of-hospital cardiac arrest.

    Science.gov (United States)

    Orban, Jean-Christophe; Scarlatti, Audrey; Danin, Pierre-Eric; Dellamonica, Jean; Bernardin, Gilles; Ichai, Carole

    2015-12-01

    Pathophysiology of cardiac arrest corresponds to an ischemia-reperfusion syndrome with deep impairment of microcirculation. Muscular tissue oxygen saturation (StO2) is a noninvasive method of evaluation of microcirculation. Our study was aimed at assessing the prognosis value of muscular StO2 in patients admitted for out-of-hospital cardiac arrest (OHCA) and treated with hypothermia. We conducted a prospective bicentric observational study including OHCA patients treated with therapeutic hypothermia. Baseline StO2, derived variables (desaturation and resaturation slopes), and lactate levels were compared at different times between patients with good and poor outcomes. Prognosis was assessed by the Cerebral Performance Category (CPC) score at 6 months after admission (CPC 1-2, good outcome; CPC 3-5, poor outcome). Forty-four patients were included, 17 good and 27 poor outcomes at 6 months. At admission, StO2 and lactate levels were lower in good outcome patients. Desaturation and resaturation slopes did not differ between groups. After an OHCA treated with therapeutic hypothermia, StO2 was correlated with outcome. Further research is needed to better understand the pathophysiological process underlying our results. Copyright © 2015 Elsevier Inc. All rights reserved.

  6. Brain oxygen saturation assessment in neonates using T2-prepared blood imaging of oxygen saturation and near-infrared spectroscopy

    DEFF Research Database (Denmark)

    Alderliesten, Thomas; De Vis, Jill B; Lemmers, Petra Ma

    2017-01-01

    saturation in the sagittal sinus (R(2 )= 0.49, p = 0.023), but no significant correlations could be demonstrated with frontal and whole brain cerebral blood flow. These results suggest that measuring oxygen saturation by T2-prepared blood imaging of oxygen saturation is feasible, even in neonates. Strong...... sinus. A strong linear relation was found between the oxygen saturation measured by magnetic resonance imaging and the oxygen saturation measured by near-infrared spectroscopy (R(2 )= 0.64, p ..., and magnetic resonance imaging measures of frontal cerebral blood flow, whole brain cerebral blood flow and venous oxygen saturation in the sagittal sinus (R(2 )= 0.71, 0.50, 0.65; p 

  7. In-vivo quantitative measurement of tissue oxygen saturation of human webbing using a transmission type continuous-wave near-infrared spectroscopy

    Science.gov (United States)

    Aizimu, Tuerxun; Adachi, Makoto; Nakano, Kazuya; Ohnishi, Takashi; Nakaguchi, Toshiya; Takahashi, Nozomi; Nakada, Taka-aki; Oda, Shigeto; Haneishi, Hideaki

    2018-02-01

    Near-infrared spectroscopy (NIRS) is a noninvasive method for monitoring tissue oxygen saturation (StO2). Many commercial NIRS devices are presently available. However, the precision of those devices is relatively poor because they are using the reflectance-model with which it is difficult to obtain the blood volume and other unchanged components of the tissue. Human webbing is a thin part of the hand and suitable to measure spectral transmittance. In this paper, we present a method for measuring StO2 of human webbing from a transmissive continuous-wave nearinfrared spectroscopy (CW-NIRS) data. The method is based on the modified Beer-Lambert law (MBL) and it consists of two steps. In the first step, we give a pressure to the upstream region of the measurement point to perturb the concentration of deoxy- and oxy-hemoglobin as remaining the other components and measure the spectral signals. From the measured data, spectral absorbance due to the components other than hemoglobin is calculated. In the second step, spectral measurement is performed at arbitrary time instance and the spectral absorbance obtained in the step 1 is subtracted from the measured absorbance. The tissue oxygen saturation (StO2) is estimated from the remained data. The method was evaluated on an arterial occlusion test (AOT) and a venous occlusion test (VOT). In the evaluation experiment, we confirmed that reasonable values of StO2 were obtained by the proposed method.

  8. Cerebral time domain-NIRS: reproducibility analysis, optical properties, hemoglobin species and tissue oxygen saturation in a cohort of adult subjects.

    Science.gov (United States)

    Giacalone, Giacomo; Zanoletti, Marta; Contini, Davide; Re, Rebecca; Spinelli, Lorenzo; Roveri, Luisa; Torricelli, Alessandro

    2017-11-01

    The reproducibility of cerebral time-domain near-infrared spectroscopy (TD-NIRS) has not been investigated so far. Besides, reference intervals of cerebral optical properties, of absolute concentrations of deoxygenated-hemoglobin (HbR), oxygenated-hemoglobin (HbO), total hemoglobin (HbT) and tissue oxygen saturation (StO 2 ) and their variability have not been reported. We have addressed these issues on a sample of 88 adult healthy subjects. TD-NIRS measurements at 690, 785, 830 nm were fitted with the diffusion model for semi-infinite homogenous media. Reproducibility, performed on 3 measurements at 5 minutes intervals, ranges from 1.8 to 6.9% for each of the hemoglobin species. The mean ± SD global values of HbR, HbO, HbT, StO 2 are respectively 24 ± 7 μM, 33.3 ± 9.5 μM, 57.4 ± 15.8 μM, 58 ± 4.2%. StO 2 displays the narrowest range of variability across brain regions.

  9. Assessment of tissue oxygen saturation during a vascular occlusion test using near-infrared spectroscopy: the role of probe spacing and measurement site studied in healthy volunteers

    NARCIS (Netherlands)

    Bezemer, R.; Lima, A.; Myers, D.; Klijn, E.; Heger, M.; Goedhart, P.T.; Bakker, J.; Ince, C.

    2009-01-01

    INTRODUCTION: To assess potential metabolic and microcirculatory alterations in critically ill patients, near-infrared spectroscopy (NIRS) has been used, in combination with a vascular occlusion test (VOT), for the non-invasive measurement of tissue oxygen saturation (StO2), oxygen consumption, and

  10. Minimally invasive prediction of ScvO2 in high-risk surgery : The introduction of a model Index of Oxygenation

    NARCIS (Netherlands)

    de Grooth, Harm-Jan S.; Vos, Jaap Jan; Scheeren, Thomas; van Beest, Paul

    2014-01-01

    INTRODUCTION: The purpose of this study was to examine the trilateral relationship between cardiac index (CI), tissue oxygen saturation (StO2) and central venous oxygen saturation (ScvO2) and subsequently develop a model to predict ScvO2 on minimal invasive manner in patients undergoing major

  11. The SafeBoosC Phase II Randomised Clinical Trial : A Treatment Guideline for Targeted Near-Infrared-Derived Cerebral Tissue Oxygenation versus Standard Treatment in Extremely Preterm Infants

    NARCIS (Netherlands)

    Pellicer, Adelina; Greisen, Gorm; Benders, Manon; Claris, Olivier; Dempsey, Eugene; Fumagalli, Monica; Gluud, Christian; Hagmann, Cornelia; Hellstroem-Westas, Lena; Hyttel-Sorensen, Simon; Lemmers, Petra; Naulaers, Gunnar; Pichler, Gerhard; Roll, Claudia; van Bel, Frank; van Oeveren, Wim; Skoog, Maria; Wolf, Martin; Austin, Topun

    2013-01-01

    Near-infrared spectroscopy-derived regional tissue oxygen saturation of haemoglobin (rSto(2)) reflects venous oxygen saturation. If cerebral metabolism is stable, rSto(2) can be used as an estimate of cerebral oxygen delivery. The SafeBoosC phase II randomised clinical trial hypothesises that the

  12. Cerebral time domain-NIRS: Reproducibility analysis, optical properties, hemoglobin species and tissue oxygen saturation in a cohort of adult subjects

    OpenAIRE

    Giacalone, Giacomo; Zanoletti, Marta; Contini, Davide; Rebecca, Re; Spinelli, Lorenzo; Roveri, Luisa; Torricelli, Alessandro

    2017-01-01

    The reproducibility of cerebral time-domain near-infrared spectroscopy (TD-NIRS) has not been investigated so far. Besides, reference intervals of cerebral optical properties, of absolute concentrations of deoxygenated-hemoglobin (HbR), oxygenated-hemoglobin (HbO), total hemoglobin (HbT) and tissue oxygen saturation (StO2) and their variability have not been reported. We have addressed these issues on a sample of 88 adult healthy subjects. TD-NIRS measurements at 690, 785, 830 nm were fitted ...

  13. Comparison of pulseoximetry oxygen saturation and arterial oxygen saturation in open heart intensive care unit

    Directory of Open Access Journals (Sweden)

    Alireza Mahoori

    2013-08-01

    Full Text Available Background: Pulseoximetry is widely used in the critical care setting, currently used to guide therapeutic interventions. Few studies have evaluated the accuracy of SPO2 (puls-eoximetry oxygen saturation in intensive care unit after cardiac surgery. Our objective was to compare pulseoximetry with arterial oxygen saturation (SaO2 during clinical routine in such patients, and to examine the effect of mild acidosis on this relationship.Methods: In an observational prospective study 80 patients were evaluated in intensive care unit after cardiac surgery. SPO2 was recorded and compared with SaO2 obtained by blood gas analysis. One or serial arterial blood gas analyses (ABGs were performed via a radial artery line while a reliable pulseoximeter signal was present. One hundred thirty seven samples were collected and for each blood gas analyses, SaO2 and SPO2 we recorded.Results: O2 saturation as a marker of peripheral perfusion was measured by Pulseoxim-etry (SPO2. The mean difference between arterial oxygen saturation and pulseoximetry oxygen saturation was 0.12%±1.6%. A total of 137 paired readings demonstrated good correlation (r=0.754; P<0.0001 between changes in SPO2 and those in SaO2 in samples with normal hemoglobin. Also in forty seven samples with mild acidosis, paired readings demonstrated good correlation (r=0.799; P<0.0001 and the mean difference between SaO2 and SPO2 was 0.05%±1.5%.Conclusion: Data showed that in patients with stable hemodynamic and good signal quality, changes in pulseoximetry oxygen saturation reliably predict equivalent changes in arterial oxygen saturation. Mild acidosis doesn’t alter the relation between SPO2 and SaO2 to any clinically important extent. In conclusion, the pulse oximeter is useful to monitor oxygen saturation in patients with stable hemodynamic.

  14. Processing and Distribution of STO2 Data

    Science.gov (United States)

    Goldsmith, Paul

    We propose in this ADAP to reduce the data obtained in the December 2016 flight of the STO2 Antarctic Balloon observatory. In just over 20 days of taking data, STO2 observed over 2.5 square degrees of the inner Milky Way in the 1900 GHz (158 m) fine structure line of ionized carbon ([CII]). This includes over 320,000 spectra with velocity resolution of 0.16 km/s and angular resolution 1 . In common with the higher bands of the Herschel HIFI instrument that also employed hot electron bolometer (HEB) mixers, there are significant baseline issues with the data that make reduction a significant challenge. Due to the year’s postponement of STO2 launch due to weather in 2015/16 season, funds for data analysis were largely redirected to support the team who enabled the successful launch and flight. A supplementary focused effort is thus needed to make STO2 data readily usable by the astronomical community, which is what we propose here. This ADAP will be a two-year program, including the following steps:: (1) Refine and optimize algorithms for excision of bad channels, correction for receiver gain changes, removal of variable bad baselines, final baseline adjustment, and verification of calibration. (2) Develop and integrated pipeline incorporating the optimized algorithms; process entire STO2 data set using the pipeline, and make an initial release of the data (DR1) to the public. (3) Refine data calibration including ancillary data sets coincident with the STO2 fields, make the data VO-compliant. (4) Write documentation for the pipeline and publish in appropriate journal; release final second data release (DR2) to the public, and hand off to permanent data repositories the NASA/IPAC IRSA database and the Harvard University Dataverse, and Cyverse, led by the University of Arizona. Members of the STO2 data reduction team have extensive experience with HIFI data, and particularly with the HEB fine structure spectra. We are thus confident that we can build on this

  15. Misconceptions in Reporting Oxygen Saturation

    NARCIS (Netherlands)

    Toffaletti, John; Zijlstra, Willem G.

    2007-01-01

    BACKGROUND: We describe some misconceptions that have become common practice in reporting blood gas and cooximetry results. In 1980, oxygen saturation was incorrectly redefined in a report of a new instrument for analysis of hemoglobin (Hb) derivatives. Oxygen saturation (sO(2)) was redefined as the

  16. Cutaneous Mitochondrial PO2, but Not Tissue Oxygen Saturation, Is an Early Indicator of the Physiologic Limit of Hemodilution in the Pig.

    Science.gov (United States)

    Römers, Luuk H L; Bakker, Charlotte; Dollée, Nathalie; Hoeks, Sanne E; Lima, Alexandre; Raat, Nicolaas J H; Johannes, Tanja; Stolker, Robert J; Mik, Egbert G

    2016-07-01

    Hemodilution is a consequence of fluid replacement during blood loss and is limited by the individual ability to compensate for decreasing hemoglobin level. We tested the ability of a novel noninvasive method for measuring cutaneous mitochondrial PO2 (mitoPO2) to detect this threshold early. Anesthetized and ventilated pigs were hemodynamically monitored and randomized into a hemodilution (n = 12) or a time control (TC) group (n = 14). MitoPO2 measurements were done by oxygen-dependent delayed fluorescence of protoporphyrin IX after preparation of the skin with 20% 5-aminolevulinic acid cream. Tissue oxygen saturation (StO2) was measured with near infrared spectroscopy on the thoracic wall. After baseline measurements, progressive normovolemic hemodilution was performed in the hemodilution group in equal steps (500 ml blood replaced by 500 ml Voluven; Fresenius Kabi AG, Germany). Consecutive measurements were performed after 20-min stabilization periods and repeated 8 times or until the animal died. The TC animals remained stable with regard to hemodynamics and mitoPO2. In the hemodilution group, mitoPO2 became hemoglobin-dependent after reaching a threshold of 2.6 ± 0.2 g/dl. During hemodilution, hemoglobin and mitoPO2 decreased (7.9 ± 0.2 to 2.1 ± 0.2 g/dl; 23.6 ± 2 to 9.9 ± 0.8 mmHg), but StO2 did not. Notably, mitoPO2 dropped quite abruptly (about 39%) at the individual threshold. We observed that this decrease in mitoPO2 occurred at least one hemodilution step before changes in other conventional parameters. Cutaneous mitoPO2 decreased typically one hemodilution step before occurrence of significant alterations in systemic oxygen consumption and lactate levels. This makes mitoPO2 a potential early indicator of the physiologic limit of hemodilution and possibly a physiologic trigger for blood transfusion.

  17. Optimal oxygen saturation in premature infants

    Directory of Open Access Journals (Sweden)

    Meayoung Chang

    2011-09-01

    Full Text Available There is a delicate balance between too little and too much supplemental oxygen exposure in premature infants. Since underuse and overuse of supplemental oxygen can harm premature infants, oxygen saturation levels must be monitored and kept at less than 95% to prevent reactive oxygen species-related diseases, such as retinopathy of prematurity and bronchopulmonary dysplasia. At the same time, desaturation below 80 to 85% must be avoided to prevent adverse consequences, such as cerebral palsy. It is still unclear what range of oxygen saturation is appropriate for premature infants; however, until the results of further studies are available, a reasonable target for pulse oxygen saturation (SpO2 is 90 to 93% with an intermittent review of the correlation between SpO2 and the partial pressure of arterial oxygen tension (PaO2. Because optimal oxygenation depends on individuals at the bedside making ongoing adjustments, each unit must define an optimal target range and set alarm limits according to their own equipment or conditions. All staff must be aware of these values and adjust the concentration of supplemental oxygen frequently.

  18. Retinal Vessel Oxygen Saturation during 100% Oxygen Breathing in Healthy Individuals.

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    Olof Birna Olafsdottir

    Full Text Available To detect how systemic hyperoxia affects oxygen saturation in retinal arterioles and venules in healthy individuals.Retinal vessel oxygen saturation was measured in 30 healthy individuals with a spectrophotometric retinal oximeter (Oxymap T1. Oximetry was performed during breathing of room air, 100% oxygen (10 minutes, 6L/min and then again room air (10 minutes recovery.Mean oxygen saturation rises modestly in retinal arterioles during 100% oxygen breathing (94.5%±3.8 vs. 92.0%±3.7% at baseline, p<0.0001 and dramatically in retinal venules (76.2%±8.0% vs. 51.3%±5.6%, p<0.0001. The arteriovenous difference decreased during 100% oxygen breathing (18.3%±9.0% vs. 40.7%±5.7%, p<0.0001. The mean diameter of arterioles decreased during 100% oxygen breathing compared to baseline (9.7±1.4 pixels vs. 10.3±1.3 pixels, p<0.0001 and the same applies to the mean venular diameter (11.4±1.2 pixels vs. 13.3±1.5 pixels, p<0.0001.Breathing 100% oxygen increases oxygen saturation in retinal arterioles and more so in venules and constricts them compared to baseline levels. The dramatic increase in oxygen saturation in venules reflects oxygen flow from the choroid and the unusual vascular anatomy and oxygen physiology of the eye.

  19. Femoral venous oxygen saturation is no surrogate for central venous oxygen saturation

    NARCIS (Netherlands)

    van Beest, Paul A.; van der Schors, Alice; Liefers, Henriëtte; Coenen, Ludo G. J.; Braam, Richard L.; Habib, Najib; Braber, Annemarije; Scheeren, Thomas W. L.; Kuiper, Michaël A.; Spronk, Peter E.

    2012-01-01

    Objective: The purpose of our study was to determine if central venous oxygen saturation and femoral venous oxygen saturation can be used interchangeably during surgery and in critically ill patients. Design: Prospective observational controlled study. Setting: Nonacademic university-affiliated

  20. Femoral venous oxygen saturation is no surrogate for central venous oxygen saturation

    NARCIS (Netherlands)

    van Beest, Paul A.; van der Schors, Alice; Liefers, Henriette; Coenen, Ludo G. J.; Braam, Richard L.; Habib, Najib; Braber, Annemarije; Scheeren, Thomas W. L.; Kuiper, Michael A.; Spronk, Peter E.

    2012-01-01

    Objective:  The purpose of our study was to determine if central venous oxygen saturation and femoral venous oxygen saturation can be used interchangeably during surgery and in critically ill patients. Design:  Prospective observational controlled study. Setting:  Nonacademic university-affiliated

  1. Relating oxygen partial pressure, saturation and content: the haemoglobin-oxygen dissociation curve.

    Science.gov (United States)

    Collins, Julie-Ann; Rudenski, Aram; Gibson, John; Howard, Luke; O'Driscoll, Ronan

    2015-09-01

    The delivery of oxygen by arterial blood to the tissues of the body has a number of critical determinants including blood oxygen concentration (content), saturation (S O2 ) and partial pressure, haemoglobin concentration and cardiac output, including its distribution. The haemoglobin-oxygen dissociation curve, a graphical representation of the relationship between oxygen satur-ation and oxygen partial pressure helps us to understand some of the principles underpinning this process. Historically this curve was derived from very limited data based on blood samples from small numbers of healthy subjects which were manipulated in vitro and ultimately determined by equations such as those described by Severinghaus in 1979. In a study of 3524 clinical specimens, we found that this equation estimated the S O2 in blood from patients with normal pH and S O2 >70% with remarkable accuracy and, to our knowledge, this is the first large-scale validation of this equation using clinical samples. Oxygen saturation by pulse oximetry (S pO2 ) is nowadays the standard clinical method for assessing arterial oxygen saturation, providing a convenient, pain-free means of continuously assessing oxygenation, provided the interpreting clinician is aware of important limitations. The use of pulse oximetry reduces the need for arterial blood gas analysis (S aO2 ) as many patients who are not at risk of hypercapnic respiratory failure or metabolic acidosis and have acceptable S pO2 do not necessarily require blood gas analysis. While arterial sampling remains the gold-standard method of assessing ventilation and oxygenation, in those patients in whom blood gas analysis is indicated, arterialised capillary samples also have a valuable role in patient care. The clinical role of venous blood gases however remains less well defined.

  2. Arterial blood oxygen saturation during blood pressure cuff-induced hypoperfusion

    International Nuclear Information System (INIS)

    Kyriacou, P A; Shafqat, K; Pal, S K

    2007-01-01

    Pulse oximetry has been one of the most significant technological advances in clinical monitoring in the last two decades. Pulse oximetry is a non-invasive photometric technique that provides information about the arterial blood oxygen saturation (SpO 2 ) and heart rate, and has widespread clinical applications. When peripheral perfusion is poor, as in states of hypovolaemia, hypothermia and vasoconstriction, oxygenation readings become unreliable or cease. The problem arises because conventional pulse oximetry sensors must be attached to the most peripheral parts of the body, such as finger, ear or toe, where pulsatile flow is most easily compromised. Pulse oximeters estimate arterial oxygen saturation by shining light at two different wavelengths, red and infrared, through vascular tissue. In this method the ac pulsatile photoplethysmographic (PPG) signal associated with cardiac contraction is assumed to be attributable solely to the arterial blood component. The amplitudes of the red and infrared ac PPG signals are sensitive to changes in arterial oxygen saturation because of differences in the light absorption of oxygenated and deoxygenated haemoglobin at these two wavelengths. From the ratios of these amplitudes, and the corresponding dc photoplethysmographic components, arterial blood oxygen saturation (SpO 2 ) is estimated. Hence, the technique of pulse oximetry relies on the presence of adequate peripheral arterial pulsations, which are detected as photoplethysmographic (PPG) signals. The aim of this study was to investigate the effect of pressure cuff-induced hypoperfusion on photoplethysmographic signals and arterial blood oxygen saturation using a custom made finger blood oxygen saturation PPG/SpO 2 sensor and a commercial finger pulse oximeter. Blood oxygen saturation values from the custom oxygen saturation sensor and a commercial finger oxygen saturation sensor were recorded from 14 healthy volunteers at various induced brachial pressures. Both pulse

  3. Arterial blood oxygen saturation during blood pressure cuff-induced hypoperfusion

    Science.gov (United States)

    Kyriacou, P. A.; Shafqat, K.; Pal, S. K.

    2007-10-01

    Pulse oximetry has been one of the most significant technological advances in clinical monitoring in the last two decades. Pulse oximetry is a non-invasive photometric technique that provides information about the arterial blood oxygen saturation (SpO2) and heart rate, and has widespread clinical applications. When peripheral perfusion is poor, as in states of hypovolaemia, hypothermia and vasoconstriction, oxygenation readings become unreliable or cease. The problem arises because conventional pulse oximetry sensors must be attached to the most peripheral parts of the body, such as finger, ear or toe, where pulsatile flow is most easily compromised. Pulse oximeters estimate arterial oxygen saturation by shining light at two different wavelengths, red and infrared, through vascular tissue. In this method the ac pulsatile photoplethysmographic (PPG) signal associated with cardiac contraction is assumed to be attributable solely to the arterial blood component. The amplitudes of the red and infrared ac PPG signals are sensitive to changes in arterial oxygen saturation because of differences in the light absorption of oxygenated and deoxygenated haemoglobin at these two wavelengths. From the ratios of these amplitudes, and the corresponding dc photoplethysmographic components, arterial blood oxygen saturation (SpO2) is estimated. Hence, the technique of pulse oximetry relies on the presence of adequate peripheral arterial pulsations, which are detected as photoplethysmographic (PPG) signals. The aim of this study was to investigate the effect of pressure cuff-induced hypoperfusion on photoplethysmographic signals and arterial blood oxygen saturation using a custom made finger blood oxygen saturation PPG/SpO2 sensor and a commercial finger pulse oximeter. Blood oxygen saturation values from the custom oxygen saturation sensor and a commercial finger oxygen saturation sensor were recorded from 14 healthy volunteers at various induced brachial pressures. Both pulse

  4. Multispectral imaging of acute wound tissue oxygenation

    Directory of Open Access Journals (Sweden)

    Audrey Huong

    2017-05-01

    Full Text Available This paper investigates the appropriate range of values for the transcutaneous blood oxygen saturation (StO2 of granulating tissues and the surrounding tissue that can ensure timely wound recovery. This work has used a multispectral imaging system to collect wound images at wavelengths ranging between 520nm and 600nm with a resolution of 10nm. As part of this research, a pilot study was conducted on three injured individuals with superficial wounds of different wound ages at different skin locations. The StO2 value predicted for the examined wounds using the Extended Modified Lambert–Beer model revealed a mean StO2 of 61±10.3% compared to 41.6±6.2% at the surrounding tissues, and 50.1±1.53% for control sites. These preliminary results contribute to the existing knowledge on the possible range and variation of wound bed StO2 that are to be used as indicators of the functioning of the vasomotion system and wound health. This study has concluded that a high StO2 of approximately 60% and a large fluctuation in this value should precede a good progression in wound healing.

  5. Arterial blood oxygen saturation during blood pressure cuff-induced hypoperfusion

    Energy Technology Data Exchange (ETDEWEB)

    Kyriacou, P A [School of Engineering and Mathematical Sciences, City University, London EC1V 0HB (United Kingdom); Shafqat, K [School of Engineering and Mathematical Sciences, City University, London EC1V 0HB (United Kingdom); Pal, S K [St Andrew' s Centre for Plastic Surgery and Burns, Broomfield Hospital, Chelmsford, CM1 7ET (United Kingdom)

    2007-10-15

    Pulse oximetry has been one of the most significant technological advances in clinical monitoring in the last two decades. Pulse oximetry is a non-invasive photometric technique that provides information about the arterial blood oxygen saturation (SpO{sub 2}) and heart rate, and has widespread clinical applications. When peripheral perfusion is poor, as in states of hypovolaemia, hypothermia and vasoconstriction, oxygenation readings become unreliable or cease. The problem arises because conventional pulse oximetry sensors must be attached to the most peripheral parts of the body, such as finger, ear or toe, where pulsatile flow is most easily compromised. Pulse oximeters estimate arterial oxygen saturation by shining light at two different wavelengths, red and infrared, through vascular tissue. In this method the ac pulsatile photoplethysmographic (PPG) signal associated with cardiac contraction is assumed to be attributable solely to the arterial blood component. The amplitudes of the red and infrared ac PPG signals are sensitive to changes in arterial oxygen saturation because of differences in the light absorption of oxygenated and deoxygenated haemoglobin at these two wavelengths. From the ratios of these amplitudes, and the corresponding dc photoplethysmographic components, arterial blood oxygen saturation (SpO{sub 2}) is estimated. Hence, the technique of pulse oximetry relies on the presence of adequate peripheral arterial pulsations, which are detected as photoplethysmographic (PPG) signals. The aim of this study was to investigate the effect of pressure cuff-induced hypoperfusion on photoplethysmographic signals and arterial blood oxygen saturation using a custom made finger blood oxygen saturation PPG/SpO{sub 2} sensor and a commercial finger pulse oximeter. Blood oxygen saturation values from the custom oxygen saturation sensor and a commercial finger oxygen saturation sensor were recorded from 14 healthy volunteers at various induced brachial pressures

  6. Relating oxygen partial pressure, saturation and content: the haemoglobin–oxygen dissociation curve

    Directory of Open Access Journals (Sweden)

    Julie-Ann Collins

    2015-09-01

    The delivery of oxygen by arterial blood to the tissues of the body has a number of critical determinants including blood oxygen concentration (content, saturation (SO2 and partial pressure, haemoglobin concentration and cardiac output, including its distribution. The haemoglobin–oxygen dissociation curve, a graphical representation of the relationship between oxygen satur­ation and oxygen partial pressure helps us to understand some of the principles underpinning this process. Historically this curve was derived from very limited data based on blood samples from small numbers of healthy subjects which were manipulated in vitro and ultimately determined by equations such as those described by Severinghaus in 1979. In a study of 3524 clinical specimens, we found that this equation estimated the SO2 in blood from patients with normal pH and SO2 >70% with remarkable accuracy and, to our knowledge, this is the first large-scale validation of this equation using clinical samples. Oxygen saturation by pulse oximetry (SpO2 is nowadays the standard clinical method for assessing arterial oxygen saturation, providing a convenient, pain-free means of continuously assessing oxygenation, provided the interpreting clinician is aware of important limitations. The use of pulse oximetry reduces the need for arterial blood gas analysis (SaO2 as many patients who are not at risk of hypercapnic respiratory failure or metabolic acidosis and have acceptable SpO2 do not necessarily require blood gas analysis. While arterial sampling remains the gold-standard method of assessing ventilation and oxygenation, in those patients in whom blood gas analysis is indicated, arterialised capillary samples also have a valuable role in patient care. The clinical role of venous blood gases however remains less well defined.

  7. Reduced cortical microvascular oxygenation in multiple sclerosis: a blinded, case-controlled study using a novel quantitative near-infrared spectroscopy method

    Science.gov (United States)

    Yang, Runze; Dunn, Jeff F.

    2015-11-01

    Hypoxia (low oxygen) is associated with many brain disorders as well as inflammation, but the lack of widely available technology has limited our ability to study hypoxia in human brain. Multiple sclerosis (MS) is a poorly understood neurological disease with a significant inflammatory component which may cause hypoxia. We hypothesized that if hypoxia were to occur, there should be reduced microvascular hemoglobin saturation (StO2). In this study, we aimed to determine if reduced StO2 can be detected in MS using frequency domain near-infrared spectroscopy (fdNIRS). We measured fdNIRS data in cortex and assessed disability of 3 clinical isolated syndrome (CIS), 72 MS patients and 12 controls. Control StO2 was 63.5 ± 3% (mean ± SD). In MS patients, 42% of StO2 values were more than 2 × SD lower than the control mean. There was a significant relationship between StO2 and clinical disability. A reduced microvascular StO2 is supportive (although not conclusive) that there may be hypoxic regions in MS brain. This is the first study showing how quantitative NIRS can be used to detect reduced StO2 in patients with MS, opening the door to understanding how microvascular oxygenation impacts neurological conditions.

  8. Toward translating near-infrared spectroscopy oxygen saturation data for the non-invasive prediction of spatial and temporal hemodynamics during exercise

    Science.gov (United States)

    Ellwein, Laura; Samyn, Margaret M.; Danduran, Michael; Schindler-Ivens, Sheila; Liebham, Stacy; LaDisa, John F.

    2016-01-01

    Image-based computational fluid dynamics (CFD) studies conducted at rest have shown that atherosclerotic plaque in the thoracic aorta (TA) correlates with adverse wall shear stress (WSS), but there is a paucity of such data under elevated flow conditions. We developed a pedaling exercise protocol to obtain phase contrast magnetic resonance imaging (PC-MRI) blood flow measurements in the TA and brachiocephalic arteries during three-tiered supine pedaling at 130%, 150%, and 170% of resting heart rate (HR), and relate these measurements to noninvasive tissue oxygen saturation (StO2) acquired by near-infrared spectroscopy (NIRS) while conducting the same protocol. Local quantification of WSS indices by CFD revealed low time-averaged WSS on the outer curvature of the ascending aorta and the inner curvature of the descending aorta (dAo) that progressively increased with exercise, but that remained low on the anterior surface of brachiocephalic arteries. High oscillatory WSS observed on the inner curvature of the aorta persisted during exercise as well. Results suggest locally continuous exposure to potentially deleterious indices of WSS despite benefits of exercise. Linear relationships between flow distributions and tissue oxygen extraction calculated from StO2 were found between the left common carotid versus cerebral tissue (r2=0.96) and the dAo versus leg tissue (r2=0.87). A resulting six-step procedure is presented to use NIRS data as a surrogate for exercise PC-MRI when setting boundary conditions for future CFD studies of the TA under simulated exercise conditions. Relationships and ensemble averaged PC-MRI inflow waveforms are provided in an online repository for this purpose. PMID:27376865

  9. Changes in muscle tissue oxygenation during stagnant ischemia in septic patients.

    Science.gov (United States)

    Pareznik, Roman; Knezevic, Rajko; Voga, Gorazd; Podbregar, Matej

    2006-01-01

    To determine changes in the rate of thenar muscles tissue deoxygenation during stagnant ischemia in patients with severe sepsis and septic shock. Prospective observational study in the medical ICU of a general hospital. Consecutive patients admitted to ICU with septic shock (n=6), severe sepsis (n=6), localized infection (n=3), and healthy volunteers (n=15). Upper limb ischemia was induced by rapid automatic pneumatic cuff inflation around upper arm. Thenar muscle tissue oxygen saturation (StO2) was measured continuously by near-infrared spectroscopy before and during upper limb ischemia. StO(2) before intervention was comparable in patients with septic shock, severe sepsis, or localized infection and healthy volunteers (89 [65, 92]% vs. 82 [72, 91]% vs. 87 [85, 92]% vs. 83 [79, 93]%, respectively; p>0.1). The rate of StO(2) decrease during stagnant ischemia after initial hemodynamic stabilization was slower in septic shock patients than in those with severe sepsis or localized infection and in controls (-7.0 [-3.6, -11.0] %/min vs. -10.4 [-7.8, -13.3] %/min vs. -19.5 [-12.3, -23.3] vs. -37.4 [-27.3, -56.2] %/min, respectively; p=0.041). At ICU discharge the rate of StO2 decrease did not differ between the septic shock, severe sepsis, and localized infection groups (-17.0 [-9.3, -28.9] %/min vs. -19.9 [-13.3, -23.6] %/min vs. -23.1 [-20.7, -26.2] %/min, respectively), but remained slower than in controls (p<0.01). The rate of StO2 decrease was correlated with Sequential Organ Failure Assessment (SOFA) score (r=0.739, p<0.001). After hemodynamic stabilization thenar muscle tissue oxygen saturation during stagnant ischemia decreases slower in septic shock patients than in patients with severe sepsis or localized infection and in healthy volunteers. During ICU stay and improvement of sepsis the muscle tissue deoxygenation rate increases in survivors of both septic shock and severe sepsis and was correlated with SOFA score.

  10. Muscle tissue saturation in humans studied with two non-invasive optical techniques: a comparative study

    Science.gov (United States)

    Shaharin, Alfi; Krite Svanberg, Emilie; Ellerström, Ida; Subash, Arman Ahamed; Khoptyar, Dmitry; Andersson-Engels, Stefan; Åkeson, Jonas

    2013-11-01

    Muscle tissue saturation (StO2) has been measured with two non-invasive optical techniques and the results were compared. One of the techniques is widely used in the hospitals - the CW-NIRS technique. The other is the photon timeof- flight spectrometer (pTOFS) developed in the Group of Biophotonics, Lund University, Sweden. The wavelengths used in both the techniques are 730 nm and 810 nm. A campaign was arranged to perform measurements on 21 (17 were taken for comparison) healthy adult volunteers (8 women and 13 men). Oxygen saturations were measured at the right lower arm of each volunteer. To observe the effects of different provocations on the oxygen saturation a blood pressure cuff was attached in the upper right arm. For CW-NIRS, the tissue saturation values were in the range from 70-90%, while for pTOFS the values were in the range from 55-60%.

  11. Growth and micro structural studies on Yittria Stabilized Zirconia (YSZ) and Strontium Titanate (STO) buffer layers

    Energy Technology Data Exchange (ETDEWEB)

    Srinivas, S.; Bhatnagar, A.K. [Univ. of Hyderabad (India); Pinto, R. [Solid State Electronics Group, Bombay (India)] [and others

    1994-12-31

    Microstructure of Yittria Stabilized Zirconia (YSZ) and Strontium Titanate (STO) of radio frequency magnetron sputtered buffer layers was studied at various sputtering conditions on Si<100>, Sapphire and LaAlO{sub 3} <100> substrates. The effect of substrate temperatures upto 800 C and sputtering gas pressures in the range of 50 mTorr. of growth conditions was studied. The buffer layers of YSZ and STO showed a strong tendency for columnar structure with variation growth conditions. The buffer layers of YSZ and STO showed orientation. The tendency for columnar growth was observed above 15 mTorr sputtering gas pressure and at high substrate temperatures. Post annealing of these films in oxygen atmosphere reduced the oxygen deficiency and strain generated during growth of the films. Strong c-axis oriented superconducting YBa{sub 2}Cu{sub 9}O{sub 7-x} (YBCO) thin films were obtained on these buffer layers using pulsed laser ablation technique. YBCO films deposited on multilayers of YSZ and STO were shown to have better superconducting properties.

  12. Systematic instrumental errors between oxygen saturation analysers in fetal blood during deep hypoxemia.

    Science.gov (United States)

    Porath, M; Sinha, P; Dudenhausen, J W; Luttkus, A K

    2001-05-01

    During a study of artificially produced deep hypoxemia in fetal cord blood, systematic errors of three different oxygen saturation analysers were evaluated against a reference CO oximeter. The oxygen tensions (PO2) of 83 pre-heparinized fetal blood samples from umbilical veins were reduced by tonometry to 1.3 kPa (10 mm Hg) and 2.7 kPa (20 mm Hg). The oxygen saturation (SO2) was determined (n=1328) on a reference CO oximeter (ABL625, Radiometer Copenhagen) and on three tested instruments (two CO oximeters: Chiron865, Bayer Diagnostics; ABL700, Radiometer Copenhagen, and a portable blood gas analyser, i-STAT, Abbott). The CO oximeters measure the oxyhemoglobin and the reduced hemoglobin fractions by absorption spectrophotometry. The i-STAT system calculates the oxygen saturation from the measured pH, PO2, and PCO2. The measurements were performed in duplicate. Statistical evaluation focused on the differences between duplicate measurements and on systematic instrumental errors in oxygen saturation analysis compared to the reference CO oximeter. After tonometry, the median saturation dropped to 32.9% at a PO2=2.7 kPa (20 mm Hg), defined as saturation range 1, and to 10% SO2 at a PO2=1.3 kPa (10 mm Hg), defined as range 2. With decreasing SO2, all devices showed an increased difference between duplicate measurements. ABL625 and ABL700 showed the closest agreement between instruments (0.25% SO2 bias at saturation range 1 and -0.33% SO2 bias at saturation range 2). Chiron865 indicated higher saturation values than ABL 625 (3.07% SO2 bias at saturation range 1 and 2.28% SO2 bias at saturation range 2). Calculated saturation values (i-STAT) were more than 30% lower than the measured values of ABL625. The disagreement among CO oximeters was small but increasing under deep hypoxemia. Calculation found unacceptably low saturation.

  13. Retinal oxygen saturation before and after glaucoma surgery.

    Science.gov (United States)

    Nitta, Eri; Hirooka, Kazuyuki; Shimazaki, Takeru; Sato, Shino; Ukegawa, Kaori; Nakano, Yuki; Tsujikawa, Akitaka

    2017-08-01

    This study compared retinal vessel oxygen saturation before and after glaucoma surgery. Retinal oxygen saturation in glaucoma patients was measured using a non-invasive spectrophotometric retinal oximeter. Adequate image quality was found in 49 of the 108 consecutive glaucoma patients recruited, with 30 undergoing trabeculectomy, 11 EX-PRESS and eight trabeculotomy. Retinal oxygen saturation measurements in the retinal arterioles and venules were performed at 1 day prior to and at approximately 10 days after surgery. Statistical analysis was performed using a Student's t-test. After glaucoma surgery, intraocular pressure (IOP) decreased from 19.8 ± 7.7 mmHg to 9.0 ± 5.7 mmHg (p glaucoma surgery had an effect on the retinal venous oxygen saturation. © 2016 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

  14. [Regional cerebral oxygen saturation as a marker of hemodynamic state following cardiac surgery].

    Science.gov (United States)

    García-Hernández, J A; Aldemira-Liz, A; Martínez-López, A I; Cayuela, A; Charlo-Molina, M T; Cano-Franco, J; Loscertales-Abril, M

    2013-10-01

    Regional cerebral oxygen saturation (rSO₂) is a measure of the general state of perfusion and oxygenation. We aim to analyze the relationship between this and various hemodynamic and respiratory parameters. Forty-three patients, operated on between October 2011 and July 2012, were included in this prospective observational descriptive study. The following parameters were measured: mean arterial pressure, both arterial and central venous oxygen saturation and partial pressures of oxygen and carbon dioxide, and lactate levels. From these parameters, the oxygenation index and the oxygen extraction ratio were calculated. These measurements were studied to evaluate whether rSO₂ correlated significantly with the other parameters. The average age and weight of the patients were 27.3 months and 9.2 kg, respectively. The rSO₂ correlated positively with both central venous oxygen saturation (r=0.73, P 0.4) between the rSO₂ and central venous oxygen saturation, and between the rSO₂ and oxygen extraction ratio. Regional cerebral oxygen saturation correlates well with hemodynamic parameters - mean arterial pressure, venous saturation, and the tissue oxygen extraction. However, it does not correlate with respiratory parameters. Copyright © 2012 Asociación Española de Pediatría. Published by Elsevier Espana. All rights reserved.

  15. The StoRM Certification Process

    International Nuclear Information System (INIS)

    Ronchieri, Elisabetta; Dibenedetto, Michele; Zappi, Riccardo; Dal Pra, Stefano; Aiftimiei, Cristina; Traldi, Sergio

    2011-01-01

    StoRM is an implementation of the SRM interface version 2.2 used by all Large Hadron Collider (LHC) experiments and non-LHC experiments as SRM endpoint at different Tiers of Worldwide LHC Computing Grid. The complexity of its services and the demand of experiments and users are increasing day by day. The growing needs in terms of service level by the StoRM users communities make it necessary to design and implement a more effective testing procedure to quickly and reliably validate new StoRM candidate releases both in code side (for example via test units, and schema valuator) and in final product software (for example via functionality tests, and stress tests). Testing software service is a very critical quality activity performed in a very ad-hoc informal manner by developers, testers and users of StoRM up to now. In this paper, we describe the certification mechanism used by StoRM team to increase the robustness and reliability of the StoRM services. Various typologies of tests, such as quality, installation, configuration, functionality, stress and performance, defined on the base of a set of use cases gathered as consequence of the collaboration among the StoRM team, experiments and users, are illustrated. Each typology of test is either increased or decreased easily from time to time. The proposed mechanism is based on a new configurable testsuite. This is executed by the certification team, who is responsible for validating the release candidate package as well as bug fix (or patch) package, given a certain testbed that considers all possible use cases. In correspondence of each failure, the package is given back to developers waiting for validating a new package.

  16. Red blood cell transfusions and tissue oxygenation in anemic hematology outpatients.

    Science.gov (United States)

    Yuruk, Koray; Bartels, Sebastiaan A; Milstein, Dan M J; Bezemer, Rick; Biemond, Bart J; Ince, Can

    2012-03-01

    There is little clinical evidence that red blood cell (RBC) transfusions improve oxygen availability at the microcirculatory level. We tested the hypotheses that anemia in chronically anemic patients with relatively healthy microcirculation would be associated with low tissue hemoglobin (Hb) and tissue oxygenation levels and that these conditions would be improved after RBC transfusions. Near-infrared spectroscopy (NIRS) was used to determine tissue oxygen saturation (StO(2)) and tissue Hb index (THI; an index of the amount of Hb in the NIRS measurement volume) in the thenar eminence and sublingual tissue before and 30 minutes after RBC transfusions in 20 chronically anemic hematology outpatients. Data are presented as median (25%-75%). The patients received three (two to three) bags of RBCs in saline-adenine-glucose-mannitol with an age of 21 (7-21) days, which was infused intravenously at the rate of 0.7 bag/hr. RBC transfusions significantly increased hematocrit level from 26% (24%-28%) to 32% (30%-34%; p viscosity from 3.4 (3.1-3.5) mPa/sec to 4.2 (4.0-4.5) mPa/sec (p < 0.0001), thenar StO(2) from 81% (80%-84%) to 86% (81%-89%; p = 0.002), thenar THI from 11.2 (9.3-13.3) AU to 13.7 (9.7-15.3) AU (p = 0.024), sublingual StO(2) from 86% (81%-89%) to 91% (86%-92%; p < 0.0001), and sublingual THI from 15.2 (13.0-17.4) AU to 17.2 (13.5-19.7) AU (p = 0.040). Although anemia in chronically anemic hematology outpatients was not associated with low StO(2) and THI levels, RBC transfusions were successful in improving these variables. © 2011 American Association of Blood Banks.

  17. The relation between oxygen saturation level and retionopathy of prematurity

    Directory of Open Access Journals (Sweden)

    Mohammad Gharavi Fard

    2016-03-01

    Full Text Available Introduction: Oxygen therapy used for preterm infant disease might be associated with oxygen toxicity or oxidative stress. The exact oxygen concentration to control and maintain the arterial oxygen saturation balance is not certainly clear. We aimed to compare the efficacy of higher or lower oxygen saturations on the development of severe retinopathy of prematurity which is a major cause of blindness in preterm neonates. Methods: PubMed was searched for obtaining the relevant articles. A total of seven articles were included after studying the titles, abstracts, and the full text of retrieved articles at initial search. Inclusion criteria were all the English language human clinical randomized controlled trials with no time limitation, which studied the efficacy of low versus high oxygen saturation measured by pulse oximetry in preterm infants.Result: It can be suggested that lower limits of oxygen saturations have higher efficacy at postmesetural age of ≤28 weeks in preterm neonates. This relation has been demonstrated in five large clinical trials including three Boost trials, COT, and Support.Discussion: Applying higher concentrations of oxygen supplementations at mesentural age ≥32 weeks reduced the development of retinopathy of prematurity. Lower concentrations of oxygen saturation decreased the incidence and the development of retinopathy of prematurity in preterm neonates while applied soon after the birth.Conclusions: Targeting levels of oxygen saturation in the low or high range should be performed cautiously with attention to the postmesentural age in preterm infants at the time of starting the procedures.

  18. In vivo detection of hemoglobin oxygen saturation and carboxyhemoglobin saturation with multiwavelength photoacoustic microscopy.

    Science.gov (United States)

    Chen, Zhongjiang; Yang, Sihua; Xing, Da

    2012-08-15

    A method for noninvasively detecting hemoglobin oxygen saturation (SO2) and carboxyhemoglobin saturation (SCO) in subcutaneous microvasculature with multiwavelength photoacoustic microscopy is presented. Blood samples mixed with different concentrations of carboxyhemoglobin were used to test the feasibility and accuracy of photoacoustic microscopy compared with the blood-gas analyzer. Moreover, fixed-point detection of SO2 and SCO in mouse ear was obtained, and the changes from normoxia to carbon monoxide hypoxia were dynamically monitored in vivo. Experimental results demonstrate that multiwavelength photoacoustic microscopy can detect SO2 and SCO, which has future potential clinical applications.

  19. Oxygen diffusion-concentration in phospholipidic model membranes. An ESR-saturation study

    International Nuclear Information System (INIS)

    Vachon, A.; Lecomte, C.; Berleur, F.

    1986-04-01

    Fully hydrated liposomes of dipalmitoyl-phosphatidylcholine were labelled with 5 (or 7, 10, 12, 16)-doxyl stearic acid at pH 6 and 8, and studied by the continuous wave ESR-saturation technique. The ESR spectral magnitude depends on the hyperfrequency power P and on both T 1 and T 2 relaxation times. Saturation, i.e. the non linearity of the spectral magnitude plotted versus √P can be quantified by a P1/2 parameter (power at which the signal is half as great as it would be without saturation). If we assume T 2 weakly modified by spin exchange between paramagnetic spin probe and oxygen in triplet state, P1/2 is inversely proportional to T 1 , and becomes a sensitive parameter to appreciate the oxygen transport (oxygen diffusion-concentration product) inside the bilayers. According to the DPPC bilayer phase transition diagrams, P1/2 (oxygen diffusion-concentration) is related to the thermodynamic state of the membrane. This technique provides further informations on a particular property of a radioprotective agent, cysteamine, which seems to inhibit spin-triplet exchange and hence maximizes T 1 (minimizes P1/2). Since radioprotective agents are known to act by scavenging radiation-induced free radicals and by inhibiting oxygen-dependent free radical processes, such a result may contribute to elucidate radioprotecting mechanisms

  20. Comparison of pre-workout nitric oxide stimulating dietary supplements on skeletal muscle oxygen saturation, blood nitrate/nitrite, lipid peroxidation, and upper body exercise performance in resistance trained men

    Directory of Open Access Journals (Sweden)

    Canale Robert E

    2010-05-01

    Full Text Available Abstract Background We compared Glycine Propionyl-L-Carnitine (GlycoCarn® and three different pre-workout nutritional supplements on measures of skeletal muscle oxygen saturation (StO2, blood nitrate/nitrite (NOx, lactate (HLa, malondialdehyde (MDA, and exercise performance in men. Methods Using a randomized, double-blind, cross-over design, 19 resistance trained men performed tests of muscular power (bench press throws and endurance (10 sets of bench press to muscular failure. A placebo, GlycoCarn®, or one of three dietary supplements (SUPP1, SUPP2, SUPP3 was consumed prior to exercise, with one week separating conditions. Blood was collected before receiving the condition and immediately after exercise. StO2 was measured during the endurance test using Near Infrared Spectroscopy. Heart rate (HR and rating of perceived exertion (RPE were determined at the end of each set. Results A condition effect was noted for StO2 at the start of exercise (p = 0.02, with GlycoCarn® higher than SUPP2. A condition effect was also noted for StO2 at the end of exercise (p = 0.003, with SUPP1 lower than all other conditions. No statistically significant interaction, condition, or time effects were noted for NOx or MDA (p > 0.05; however, MDA decreased 13.7% with GlycoCarn® and increased in all other conditions. Only a time effect was noted for HLa (p 0.05; however, GlycoCarn® resulted in a statistically insignificant greater total volume load compared to the placebo (3.3%, SUPP1 (4.2%, SUPP2 (2.5%, and SUPP3 (4.6%. Conclusion None of the products tested resulted in favorable changes in our chosen outcome measures, with the exception of GlycoCarn® in terms of higher StO2 at the start of exercise. GlycoCarn® resulted in a 13.7% decrease in MDA from pre- to post-exercise and yielded a non-significant but greater total volume load compared to all other conditions. These data indicate that 1 a single ingredient (GlycoCarn® can provide similar practical benefit

  1. Renal vein oxygen saturation in renal artery stenosis

    DEFF Research Database (Denmark)

    Nielsen, K; Rehling, M; Henriksen, Jens Henrik Sahl

    1992-01-01

    Renal vein oxygen-saturation was measured in 56 patients with arterial hypertension and unilateral stenosis or occlusion of the renal artery. Oxygen-saturation in blood from the ischaemic kidney (84.4%, range 73-93%) was significantly higher than that from the 'normal' contralateral kidney (81...... than its blood flow. This is probably due to decreased filtration fraction and filtered sodium with subsequent reduction in absolute tubular re-absorption of sodium ions....

  2. TECHNIQUES OF EVALUATION OF HEMOGLOBIN OXYGEN SATURATION IN CLINICAL OPHTHALMOLOGY

    Directory of Open Access Journals (Sweden)

    S. Yu. Petrov

    2016-01-01

    Full Text Available Oxygen content in body fluids and tissues is an important indicator of life support functions. A number of ocular pathologies, e.g. glaucoma, are of presumable vascular origin which means altered blood supply and oxygen circulation. Most oxygen is transported in the blood in the association with hemoglobin. When passing through the capillaries, hemoglobin releases oxygen, converting from oxygenated form to deoxygenated form. This process is accompanied by the changes in spectral characteristics of hemoglobin which result in different colors of arterial and venous blood. Photometric technique for the measurement of oxygen saturation in blood is based on the differences in light absorption by different forms of hemoglobin. The measurement of saturation is called oximetry. Pulse oximetry with assessment of tissue oxygenation is the most commonly used method in medicine. The degree of hemoglobin oxygen saturation in the eye blood vessels is the most accessible for noninvasive studies during ophthalmoscopy and informative. Numerous studies showed the importance of this parameter for the diagnosis of retinopathy of various genesis, metabolic status analysis in hyperglycemia, diagnosis and control of treatment of glaucoma and other diseases involving alterations in eye blood supply. The specific method for evaluation of oxygen concentration is the measurement of pressure of oxygen dissolved in the blood, i.e. partial pressure of oxygen. In ophthalmological practice, this parameter is measured in anterior chamber fluid evaluating oxygen level for several ophthalmopathies including different forms of glaucoma, for instillations of hypotensive eye drops as well as in vitreous body near to the optic disc under various levels of intraocular pressure. Currently, monitoring of oxygen saturation in retinal blood vessels, i.e. retinal oximetry, is well developed. This technique is based on the assessment of light absorption by blood depending on

  3. T2-prepared velocity selective labelling : A novel idea for full-brain mapping of oxygen saturation

    NARCIS (Netherlands)

    Alderliesten, Thomas; De Vis, Jill B; Lemmers, Petra M A; van Bel, Frank; Benders, Manon J N L; Hendrikse, Jeroen; Petersen, Esben T

    2016-01-01

    BACKGROUND AND AIM: Disturbances in cerebral oxygenation saturation (SO2) have been linked to adverse outcome in adults, children, and neonates. In intensive care, the cerebral SO2 is increasingly being monitored by Near-InfraRed Spectroscopy (NIRS). Unfortunately NIRS has a limited penetration

  4. Rapid determination of oxygen saturation and vascularity for cancer detection.

    Directory of Open Access Journals (Sweden)

    Fangyao Hu

    Full Text Available A rapid heuristic ratiometric analysis for estimating tissue hemoglobin concentration and oxygen saturation from measured tissue diffuse reflectance spectra is presented. The analysis was validated in tissue-mimicking phantoms and applied to clinical measurements in head and neck, cervical and breast tissues. The analysis works in two steps. First, a linear equation that translates the ratio of the diffuse reflectance at 584 nm and 545 nm to estimate the tissue hemoglobin concentration using a Monte Carlo-based lookup table was developed. This equation is independent of tissue scattering and oxygen saturation. Second, the oxygen saturation was estimated using non-linear logistic equations that translate the ratio of the diffuse reflectance spectra at 539 nm to 545 nm into the tissue oxygen saturation. Correlations coefficients of 0.89 (0.86, 0.77 (0.71 and 0.69 (0.43 were obtained for the tissue hemoglobin concentration (oxygen saturation values extracted using the full spectral Monte Carlo and the ratiometric analysis, for clinical measurements in head and neck, breast and cervical tissues, respectively. The ratiometric analysis was more than 4000 times faster than the inverse Monte Carlo analysis for estimating tissue hemoglobin concentration and oxygen saturation in simulated phantom experiments. In addition, the discriminatory power of the two analyses was similar. These results show the potential of such empirical tools to rapidly estimate tissue hemoglobin in real-time spectral imaging applications.

  5. Oxygenation of saturated and unsaturated hydrocarbons with ...

    Indian Academy of Sciences (India)

    Unknown

    Oxygenation of saturated and unsaturated hydrocarbons with sodium periodate. 431. Table 1. Competitive oxygenation of tetralin and cyclooctene with sodium periodate catalyzed by different manga- .... Teacher Education University. My grateful thanks also extend to Dr D Mohajer for his useful sugges- tions. References. 1.

  6. Central venous oxygen saturation during hypovolaemic shock in humans

    DEFF Research Database (Denmark)

    Madsen, P; Iversen, H; Secher, N H

    1993-01-01

    We compared central venous oxygen saturation and central venous pressure (CVP) as indices of the effective blood volume during 50 degrees head-up tilt (anti-Trendelenburg's position) induced hypovolaemic shock in eight healthy subjects. Head-up tilt increased thoracic electrical impedance from 31...... (28-36) (median and range) to 34 (30-40) Ohm, mean arterial pressure (MAP) from 79 (70-88) to 86 (80-99) mmHg, heart rate (HR) from 67 (56-71) to 99 (78-119) beats min-1 (p ....05) but thereafter remained stable. In contrast, central venous oxygen saturation showed a linear decrease with time from 0.75 (0.69-0.78) at rest to 0.60 (0.49-0.67) (p measurement of central venous oxygen saturation...

  7. Lower early postnatal oxygen saturation target and risk of ductus arteriosus closure failure.

    Science.gov (United States)

    Inomata, Kei; Taniguchi, Shinji; Yonemoto, Hiroki; Inoue, Takeshi; Kawase, Akihiko; Kondo, Yuichi

    2016-11-01

    Early postnatal hyperoxia is a major risk factor for retinopathy of prematurity (ROP) in extremely premature infants. To reduce the occurrence of ROP, we adopted a lower early postnatal oxygen saturation (SpO 2 ) target range (85-92%) from April 2011. Lower SpO 2 target range, however, may lead to hypoxemia and an increase in the risk of ductus arteriosus (DA) closure failure. The aim of this study was therefore to determine whether a lower SpO 2 target range, during the early postnatal stage, increases the risk of DA closure failure. Infants born at closure failure in period 2 (21%) was significantly higher than that in period 1 (1%). On multivariate logistic regression analysis, the lower oxygen saturation target range was an independent risk factor for DA closure failure. Lower early postnatal oxygen saturation target range increases the risk of DA closure failure. © 2016 Japan Pediatric Society.

  8. The use of hemoglobin saturation ratio as a means of measuring tissue perfusion in the development of heel pressure sores.

    Science.gov (United States)

    Aliano, Kristen A; Stavrides, Steve; Davenport, Thomas

    2013-09-01

    The heel is a common site of pressure ulcers. The amount of pressure and time needed to develop these wounds is dependent on various factors including pressure surface, the patient's anatomy, and co-morbidities. We studied the use of the hemoglobin saturation ratio as a means of assessing heel perfusion in various pressure settings. The mixed perfusion ratio in the heels of 5 volunteers was assessed on 3 pressure surfaces and at the time of off-load. The surfaces studied included: stretcher pad, plastic backboard without padding, and pressure reduction gel. Each surface was measured for 5 minutes with a real-time reading. On the stretcher, the average StO2% decrease for each pressure surface was 26.2 ± 10 (range 18-43). The average StO2% decrease on the backboard was 22.8 ± 12.3 (range 8-37), and 24.0 ± 4.8 (range 19-30) on the gel pad. The StO2% drop plateaued with the stretcher and gel pad, but with the backboard there was a continued slow drop at 5 minutes. This study demonstrates that hemoglobin oxygenation ratio may be effective in assessing a tissue's direct perfusion in the setting of tissue pressure and may also be beneficial to better assess the effects of pressure-reduction surfaces. Further studies will be needed to determine time to skin breakdown as it pertains to pressure and tissue oxygenation.

  9. The influence of systemic hemodynamics and oxygen transport on cerebral oxygen saturation in neonates after the Norwood procedure.

    Science.gov (United States)

    Li, Jia; Zhang, Gencheng; Holtby, Helen; Guerguerian, Anne-Marie; Cai, Sally; Humpl, Tilman; Caldarone, Christopher A; Redington, Andrew N; Van Arsdell, Glen S

    2008-01-01

    Ischemic brain injury is an important morbidity in neonates after the Norwood procedure. Its relationship to systemic hemodynamic oxygen transport is poorly understood. Sixteen neonates undergoing the Norwood procedure were studied. Continuous cerebral oxygen saturation was measured by near-infrared spectroscopy. Continuous oxygen consumption was measured by respiratory mass spectrometry. Pulmonary and systemic blood flow, systemic vascular resistance, oxygen delivery, and oxygen extraction ratio were derived with measurements of arterial, and superior vena cava and pulmonary venous gases and pressures at 2- to 4-hour intervals during the first 72 hours in the intensive care unit. Mean cerebral oxygen saturation was 66% +/- 12% before the operation, reduced to 51% +/- 13% on arrival in the intensive care unit, and remained low during the first 8 hours; it increased to 56% +/- 9% at 72 hours, still significantly lower than the preoperative level (P blood flow and oxygen delivery (P blood flow (P = .001) and hemoglobin (P = .02) and negatively correlated with systemic vascular resistance (P = .003). It was not correlated with oxygen consumption (P > .05). Cerebral oxygen saturation decreased significantly in neonates during the early postoperative period after the Norwood procedure and was significantly influenced by systemic hemodynamic and metabolic events. As such, hemodynamic interventions to modify systemic oxygen transport may provide further opportunities to reduce the risk of cerebral ischemia and improve neurodevelopmental outcomes.

  10. Assessment of oxygen saturation in dental pulp of permanent teeth with periodontal disease.

    Science.gov (United States)

    Giovanella, Larissa Bergesch; Barletta, Fernando Branco; Felippe, Wilson Tadeu; Bruno, Kely Firmino; de Alencar, Ana Helena Gonçalves; Estrela, Carlos

    2014-12-01

    In individuals with periodontal disease, dental pulp status should be determined before a treatment plan is made. Pulse oximeters are promising diagnostic tools to evaluate pulp vascularization. This study used pulse oximetry to determine the level of oxygen saturation in dental pulp of intact permanent teeth with periodontal attachment loss (PAL) and gingival recession (GR) and to evaluate the correlation between periodontal disease and level of oxygen saturation in the pulp. This study included 67 anterior teeth of 35 patients; all teeth showed intact crowns, PAL, a periodontal pocket (PP), and GR. The teeth underwent periodontal examination, cold and electric pulp testing, and pulse oximetry measurements. The Pearson correlation coefficient and a linear regression coefficient were calculated to evaluate the degree of correlation between periodontal disease markers (PAL, PP, and GR) and the level of oxygen saturation in dental pulp. These tests also evaluated possible associations between oxygen saturation and cold and electric pulp testing. PAL, PP, and GR had negative correlations with oxygen saturation in dental pulp. Conversely, no statistically significant association was found between oxygen saturation in dental pulp and the response to electric sensibility testing. Oxygen saturation was lower in the pulp of permanent teeth with PAL, PP, and GR, indicating that periodontal disease correlates with the level of oxygen saturation in the pulp. Copyright © 2014 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  11. First observation of the decays $\\bar{B}^0_{(s)}\\to D_s^+K^-\\pi^+\\pi^-$ and $\\bar{B}^0_s\\to D_{s1}(2536)^+\\pi^-$

    CERN Document Server

    INSPIRE-00258707; Abellan Beteta, C; Adametz, A; Adeva, B; Adinolfi, M; Adrover, C; Affolder, A; Ajaltouni, Z; Albrecht, J; Alessio, F; Alexander, M; Ali, S; Alkhazov, G; Alvarez Cartelle, P; Alves Jr, A A; Amato, S; Amhis, Y; Anderlini, L; Anderson, J; Appleby, R B; Aquines Gutierrez, O; Archilli, F; Artamonov, A; Artuso, M; Aslanides, E; Auriemma, G; Bachmann, S; Back, J J; Baesso, C; Baldini, W; Barlow, R J; Barschel, C; Barsuk, S; Barter, W; Bates, A; Bauer, Th; Bay, A; Beddow, J; Bediaga, I; Belogurov, S; Belous, K; Belyaev, I; Ben-Haim, E; Benayoun, M; Bencivenni, G; Benson, S; Benton, J; Berezhnoy, A; Bernet, R; Bettler, M -O; van Beuzekom, M; Bien, A; Bifani, S; Bird, T; Bizzeti, A; Bjørnstad, P M; Blake, T; Blanc, F; Blanks, C; Blouw, J; Blusk, S; Bobrov, A; Bocci, V; Bondar, A; Bondar, N; Bonivento, W; Borghi, S; Borgia, A; Bowcock, T J V; Bozzi, C; Brambach, T; van den Brand, J; Bressieux, J; Brett, D; Britsch, M; Britton, T; Brook, N H; Brown, H; Büchler-Germann, A; Burducea, I; Bursche, A; Buytaert, J; Cadeddu, S; Callot, O; Calvi, M; Calvo Gomez, M; Camboni, A; Campana, P; Carbone, A; Carboni, G; Cardinale, R; Cardini, A; Carranza-Mejia, H; Carson, L; Carvalho Akiba, K; Casse, G; Cattaneo, M; Cauet, Ch; Charles, M; Charpentier, Ph; Chen, P; Chiapolini, N; Chrzaszcz, M; Ciba, K; Cid Vidal, X; Ciezarek, G; Clarke, P E L; Clemencic, M; Cliff, H V; Closier, J; Coca, C; Coco, V; Cogan, J; Cogneras, E; Collins, P; Comerma-Montells, A; Contu, A; Cook, A; Coombes, M; Corti, G; Couturier, B; Cowan, G A; Craik, D; Cunliffe, S; Currie, R; D'Ambrosio, C; David, P; David, P N Y; De Bonis, I; De Bruyn, K; De Capua, S; De Cian, M; De Miranda, J M; De Paula, L; De Simone, P; Decamp, D; Deckenhoff, M; Degaudenzi, H; Del Buono, L; Deplano, C; Derkach, D; Deschamps, O; Dettori, F; Di Canto, A; Dickens, J; Dijkstra, H; Diniz Batista, P; Dogaru, M; Domingo Bonal, F; Donleavy, S; Dordei, F; Dosil Suárez, A; Dossett, D; Dovbnya, A; Dupertuis, F; Dzhelyadin, R; Dziurda, A; Dzyuba, A; Easo, S; Egede, U; Egorychev, V; Eidelman, S; van Eijk, D; Eisenhardt, S; Ekelhof, R; Eklund, L; El Rifai, I; Elsasser, Ch; Elsby, D; Falabella, A; Färber, C; Fardell, G; Farinelli, C; Farry, S; Fave, V; Fernandez Albor, V; Ferreira Rodrigues, F; Ferro-Luzzi, M; Filippov, S; Fitzpatrick, C; Fontana, M; Fontanelli, F; Forty, R; Francisco, O; Frank, M; Frei, C; Frosini, M; Furcas, S; Gallas Torreira, A; Galli, D; Gandelman, M; Gandini, P; Gao, Y; Garnier, J-C; Garofoli, J; Garosi, P; Garra Tico, J; Garrido, L; Gaspar, C; Gauld, R; Gersabeck, E; Gersabeck, M; Gershon, T; Ghez, Ph; Gibson, V; Gligorov, V V; Göbel, C; Golubkov, D; Golutvin, A; Gomes, A; Gordon, H; Grabalosa Gándara, M; Graciani Diaz, R; Granado Cardoso, L A; Graugés, E; Graziani, G; Grecu, A; Greening, E; Gregson, S; Grünberg, O; Gui, B; Gushchin, E; Guz, Yu; Gys, T; Hadjivasiliou, C; Haefeli, G; Haen, C; Haines, S C; Hall, S; Hampson, T; Hansmann-Menzemer, S; Harnew, N; Harnew, S T; Harrison, J; Harrison, P F; Hartmann, T; He, J; Heijne, V; Hennessy, K; Henrard, P; Hernando Morata, J A; van Herwijnen, E; Hicks, E; Hill, D; Hoballah, M; Hopchev, P; Hulsbergen, W; Hunt, P; Huse, T; Hussain, N; Hutchcroft, D; Hynds, D; Iakovenko, V; Ilten, P; Imong, J; Jacobsson, R; Jaeger, A; Jahjah Hussein, M; Jans, E; Jansen, F; Jaton, P; Jean-Marie, B; Jing, F; John, M; Johnson, D; Jones, C R; Jost, B; Kaballo, M; Kandybei, S; Karacson, M; Karbach, T M; Kenyon, I R; Kerzel, U; Ketel, T; Keune, A; Khanji, B; Kim, Y M; Kochebina, O; Komarov, V; Koopman, R F; Koppenburg, P; Korolev, M; Kozlinskiy, A; Kravchuk, L; Kreplin, K; Kreps, M; Krocker, G; Krokovny, P; Kruse, F; Kucharczyk, M; Kudryavtsev, V; Kvaratskheliya, T; La Thi, V N; Lacarrere, D; Lafferty, G; Lai, A; Lambert, D; Lambert, R W; Lanciotti, E; Lanfranchi, G; Langenbruch, C; Latham, T; Lazzeroni, C; Le Gac, R; van Leerdam, J; Lees, J -P; Lefèvre, R; Leflat, A; Lefrançois, J; Leroy, O; Lesiak, T; Li, Y; Li Gioi, L; Liles, M; Lindner, R; Linn, C; Liu, B; Liu, G; von Loeben, J; Lopes, J H; Lopez Asamar, E; Lopez-March, N; Lu, H; Luisier, J; Luo, H; Mac Raighne, A; Machefert, F; Machikhiliyan, I V; Maciuc, F; Maev, O; Magnin, J; Maino, M; Malde, S; Manca, G; Mancinelli, G; Mangiafave, N; Marconi, U; Märki, R; Marks, J; Martellotti, G; Martens, A; Martin, L; Martín Sánchez, A; Martinelli, M; Martinez Santos, D; Martins Tostes, D; Massafferri, A; Matev, R; Mathe, Z; Matteuzzi, C; Matveev, M; Maurice, E; Mazurov, A; McCarthy, J; McGregor, G; McNulty, R; Meissner, M; Merk, M; Merkel, J; Milanes, D A; Minard, M -N; Molina Rodriguez, J; Monteil, S; Moran, D; Morawski, P; Mountain, R; Mous, I; Muheim, F; Müller, K; Muresan, R; Muryn, B; Muster, B; Mylroie-Smith, J; Naik, P; Nakada, T; Nandakumar, R; Nasteva, I; Needham, M; Neufeld, N; Nguyen, A D; Nguyen, T D; Nguyen-Mau, C; Nicol, M; Niess, V; Nikitin, N; Nikodem, T; Nomerotski, A; Novoselov, A; Oblakowska-Mucha, A; Obraztsov, V; Oggero, S; Ogilvy, S; Okhrimenko, O; Oldeman, R; Orlandea, M; Otalora Goicochea, J M; Owen, P; Pal, B K; Palano, A; Palutan, M; Panman, J; Papanestis, A; Pappagallo, M; Parkes, C; Parkinson, C J; Passaleva, G; Patel, G D; Patel, M; Patrick, G N; Patrignani, C; Pavel-Nicorescu, C; Pazos Alvarez, A; Pellegrino, A; Penso, G; Pepe Altarelli, M; Perazzini, S; Perego, D L; Perez Trigo, E; Pérez-Calero Yzquierdo, A; Perret, P; Perrin-Terrin, M; Pessina, G; Petridis, K; Petrolini, A; Phan, A; Picatoste Olloqui, E; Pie Valls, B; Pietrzyk, B; Pilař, T; Pinci, D; Playfer, S; Plo Casasus, M; Polci, F; Polok, G; Poluektov, A; Polycarpo, E; Popov, D; Popovici, B; Potterat, C; Powell, A; Prisciandaro, J; Pugatch, V; Puig Navarro, A; Qian, W; Rademacker, J H; Rakotomiaramanana, B; Rangel, M S; Raniuk, I; Rauschmayr, N; Raven, G; Redford, S; Reid, M M; dos Reis, A C; Ricciardi, S; Richards, A; Rinnert, K; Rives Molina, V; Roa Romero, D A; Robbe, P; Rodrigues, E; Rodriguez Perez, P; Rogers, G J; Roiser, S; Romanovsky, V; Romero Vidal, A; Rouvinet, J; Ruf, T; Ruiz, H; Sabatino, G; Saborido Silva, J J; Sagidova, N; Sail, P; Saitta, B; Salzmann, C; Sanmartin Sedes, B; Sannino, M; Santacesaria, R; Santamarina Rios, C; Santinelli, R; Santovetti, E; Sapunov, M; Sarti, A; Satriano, C; Satta, A; Savrie, M; Schaack, P; Schiller, M; Schindler, H; Schleich, S; Schlupp, M; Schmelling, M; Schmidt, B; Schneider, O; Schopper, A; Schune, M -H; Schwemmer, R; Sciascia, B; Sciubba, A; Seco, M; Semennikov, A; Senderowska, K; Sepp, I; Serra, N; Serrano, J; Seyfert, P; Shapkin, M; Shapoval, I; Shatalov, P; Shcheglov, Y; Shears, T; Shekhtman, L; Shevchenko, O; Shevchenko, V; Shires, A; Silva Coutinho, R; Skwarnicki, T; Smith, N A; Smith, E; Smith, M; Sobczak, K; Soler, F J P; Soomro, F; Souza, D; Souza De Paula, B; Spaan, B; Sparkes, A; Spradlin, P; Stagni, F; Stahl, S; Steinkamp, O; Stoica, S; Stone, S; Storaci, B; Straticiuc, M; Straumann, U; Subbiah, V K; Swientek, S; Szczekowski, M; Szczypka, P; Szumlak, T; T'Jampens, S; Teklishyn, M; Teodorescu, E; Teubert, F; Thomas, C; Thomas, E; van Tilburg, J; Tisserand, V; Tobin, M; Tolk, S; Tonelli, D; Topp-Joergensen, S; Torr, N; Tournefier, E; Tourneur, S; Tran, M T; Tsaregorodtsev, A; Tsopelas, P; Tuning, N; Ubeda Garcia, M; Ukleja, A; Urner, D; Uwer, U; Vagnoni, V; Valenti, G; Vazquez Gomez, R; Vazquez Regueiro, P; Vecchi, S; Velthuis, J J; Veltri, M; Veneziano, G; Vesterinen, M; Viaud, B; Videau, I; Vieira, D; Vilasis-Cardona, X; Visniakov, J; Vollhardt, A; Volyanskyy, D; Voong, D; Vorobyev, A; Vorobyev, V; Voß, C; Voss, H; Waldi, R; Wallace, R; Wandernoth, S; Wang, J; Ward, D R; Watson, N K; Webber, A D; Websdale, D; Whitehead, M; Wicht, J; Wiedner, D; Wiggers, L; Wilkinson, G; Williams, M P; Williams, M; Wilson, F F; Wishahi, J; Witek, M; Witzeling, W; Wotton, S A; Wright, S; Wu, S; Wyllie, K; Xie, Y; Xing, F; Xing, Z; Yang, Z; Young, R; Yuan, X; Yushchenko, O; Zangoli, M; Zavertyaev, M; Zhang, F; Zhang, L; Zhang, W C; Zhang, Y; Zhelezov, A; Zhong, L; Zvyagin, A

    2012-01-01

    The first observation of the decays $\\bar{B}^0_{s}\\to D_s^+K^-\\pi^+\\pi^-$ and $\\bar{B}^0\\to D_s^+K^-\\pi^+\\pi^-$ are reported using an integrated luminosity of 1.0 fb$^{-1}$ recorded by the LHCb experiment. The branching fractions, normalized with respect to $\\bar{B}^0_{s}\\to D_s^+\\pi^-\\pi^+\\pi^-$ and $\\bar{B}^0_{s}\\to D_s^+K^-\\pi^+\\pi^-$, respectively, are measured to be $\\frac{B(\\bar{B}^0_{s}\\to D_s^+K^-\\pi^+\\pi^-)}{B(\\bar{B}^0_{s}\\to D_s^+\\pi^-\\pi^+\\pi^-)} = (5.2\\pm0.5\\pm0.3)\\times10^{-2}$, $\\frac{B(\\bar{B}^0\\to D_s^+K^-\\pi^+\\pi^-)}{B(\\bar{B}^0_{s}\\to D_s^+K^-\\pi^+\\pi^-)} = 0.54\\pm0.07\\pm0.07$, where the first uncertainty is statistical and the second is systematic. The $\\bar{B}^0_{s}\\to D_s^+K^-\\pi^+\\pi^-$ decay is of particular interest as it can be used to measure the weak phase $\\gamma$. First observation of the $\\bar{B}^0_s\\to D_{s1}(2536)^+\\pi^-$, $D_{s1}^+\\to D_s^+\\pi^-\\pi^+$ decay is also presented, and its branching fraction relative to $\\bar{B}^0_{s}\\to D_s^+\\pi^-\\pi^+\\pi^-$ is found to be $\\frac{...

  12. Development of an oxygen saturation measuring system by using near-infrared spectroscopy

    Science.gov (United States)

    Kono, K.; Nakamachi, E.; Morita, Y.

    2017-08-01

    Recently, the hypoxia imaging has been recognized as the advanced technique to detect cancers because of a strong relationship with the biological characterization of cancer. In previous studies, hypoxia imaging systems for endoscopic diagnosis have been developed. However, these imaging technologies using the visible light can observe only blood vessels in gastric mucous membrane. Therefore, they could not detect scirrhous gastric cancer which accounts for 10% of all gastric cancers and spreads rapidly into submucous membrane. To overcome this problem, we developed a measuring system of blood oxygen saturation in submucous membrane by using near-infrared (NIR) spectroscopy. NIR, which has high permeability for bio-tissues and high absorbency for hemoglobin, can image and observe blood vessels in submucous membrane. NIR system with LED lights and a CCD camera module was developed to image blood vessels. We measured blood oxygen saturation using the optical density ratio (ODR) of two wavelengths, based on Lambert-Beer law. To image blood vessel clearly and measure blood oxygen saturation accurately, we searched two optimum wavelengths by using a multilayer human gastric-like phantom which has same optical properties as human gastric one. By using Monte Carlo simulation of light propagation, we derived the relationship between the ODR and blood oxygen saturation and elucidated the influence of blood vessel depth on measuring blood oxygen saturation. The oxygen saturation measuring methodology was validated with experiments using our NIR system. Finally, it was confirmed that our system can detect oxygen saturation in various depth blood vessels accurately.

  13. Correlation between Oxygen Saturation and Hemoglobin and Hematokrit Levels in Tetralogy of Fallot Patients

    Directory of Open Access Journals (Sweden)

    Farhatul Inayah Adiputri

    2016-03-01

    Full Text Available Background: Hemoglobin and hematocrit levels increase in Tetralogy of Fallot (TOF but the oxygen saturation declines. Reduced hemoglobin in circulating blood as a parameter of cyanosis does not indicate rising hemoglobin due to the ‘not-working’ hemoglobins that affect the oxygen saturation. Increasing hematocrit is the result of secondary erythrocytosis caused by declining oxygen level in blood, which is related to the oxygen saturation. This study was conducted to find the correlation between oxygen saturation and hemoglobin and hematocrite levels in TOF patients. Methods: This study was undertaken at Dr. Hasan Sadikin General Hospital in the period of January 2011 to December 2012 using the cross-sectional analytic method with total sampling technique. Inclusion criteria were medical records of TOF patients diagnosed based on echocardiography that included data on oxygen saturation, hemoglobin, and hematocrite. Exclusion criteria was the history of red blood transfusion. Results: Thirty medical records of TOF patiens from Dr. Hasan Sadikin General Hospital Bandung were included in this study. Due to skewed data distribution, Spearman correlation test was used to analyze the data. There was a significant negative correlation between oxygen saturation and hematocrit level (r= -0.412; p=0.024 and insignificant correlation between oxygen saturation and hemoglobin (r=-0.329; p= 0.076. Conclusions: There is a weak negative correlation between oxygen saturation and hematocrite levels

  14. Sodium addition and/or oxygen saturation of iohexol during normal and reduced perfusion pressure

    International Nuclear Information System (INIS)

    Baath, L.

    1990-01-01

    The influence on contractile force (CF) and the propensity for ventricular fibrillation (VF) from infusing the non-ionic contrast medium iohexol during normal (75 cm H 2 O) and reduced perfusion pressure (35 cm H 2 O) were investigated in the isolated rabbit heart. Both during normal and reduced perfusion pressure iohexol (150 mg I/ml) with oxygen saturation caused a smaller reduction of CF than iohexol without oxygen. During reduced pressure iohexol with sodium addition (28 mM NaCl) caused less depression of CF than iohexol without sodium. The combination of sodium addition and oxygen saturation had the least influence on CF. Iohexol (350 mg I/ml) without sodium had a similar fibrillatory propensity during both normal and reduced pressure. Enriching iohexol with 28 mM NaCl decreased the risk of VF. The decrease was similar during both normal and reduced pressure. The risk of VF from oxygen saturation of iohexol (350 mg I/ml, without sodium) was similar during both normal and reduced pressure. It is concluded that a small addition of sodium and/or oxygen saturation of a non-ionic monomeric contrast medium have beneficial effects on the heart both during normal perfusion pressure and during ischemia. (orig.)

  15. Validation of the Nonin 8600V Pulse Oximeter for heart rate and oxygen saturation measurements in rats.

    Science.gov (United States)

    Bernard, Susan L; An, Dowon; Glenny, Robb W

    2004-05-01

    This report validates the use and limitations of the Nonin Pulse Oximeter for measuring heart rate and oxygen saturation in rats. Eight anesthetized Sprague-Dawley rats were intubated and catheterized. Oxygen saturation was directly measured from arterial blood by using a Radiometer OSM3 Hemoximeter adjusted for rat blood as well as indirectly by using the Nonin Pulse Oximeter. Oxygen saturation was changed by varying the level of inhaled oxygen. Heart rate was measured in two ways: 1) by using the signal from the Nonin Pulse Oximeter and 2) by counting the pressure pulses from the transduced blood pressure. There was excellent agreement between heart rate values measured by the Nonin Pulse Oximeter and that measured by counting the pulses from the arterial blood pressure recording. The Nonin Pulse Oximeter underestimated oxygen saturations by about 3% to 5% compared to the Hemoximeter. Overall, the pulse oximeter reflected important trends in oxygen saturations, making it a useful tool for laboratory animal medicine.

  16. High or low oxygen saturation and severe retinopathy of prematurity: a meta-analysis.

    Science.gov (United States)

    Chen, Minghua L; Guo, Lei; Smith, Lois E H; Dammann, Christiane E L; Dammann, Olaf

    2010-06-01

    Low oxygen saturation appears to decrease the risk of severe retinopathy of prematurity (ROP) in preterm newborns when administered during the first few weeks after birth. High oxygen saturation seems to reduce the risk at later postmenstrual ages (PMAs). However, previous clinical studies are not conclusive individually. To perform a systematic review and meta-analysis to report the association between severe ROP incidence of premature infants with high or low target oxygen saturation measured by pulse oximetry. Studies were identified through PubMed and Embase literature searches through May 2009 by using the terms "retinopathy of prematurity and oxygen" or "retinopathy of prematurity and oxygen therapy." We selected 10 publications addressing the association between severe ROP and target oxygen saturation measured by pulse oximetry. Using a random-effects model we calculated the summary-effect estimate. We visually inspected funnel plots to examine possible publication bias. Low oxygen saturation (70%-96%) in the first several postnatal weeks was associated with a reduced risk of severe ROP (risk ratio [RR]: 0.48 [95% confidence interval (CI): 0.31-0.75]). High oxygen saturation (94%-99%) at > or = 32 weeks' PMA was associated with a decreased risk for progression to severe ROP (RR: 0.54 [95% CI: 0.35-0.82]). Among preterm infants with a gestational age of large randomized clinical trial with long-term developmental follow-up is warranted to confirm this meta-analytic result.

  17. Monitor hemoglobin concentration and oxygen saturation in living mouse tail using photoacoustic CT scanner

    Science.gov (United States)

    Liu, Bo; Kruger, Robert; Reinecke, Daniel; Stantz, Keith M.

    2010-02-01

    Purpose: The purpose of this study is to use PCT spectroscopy scanner to monitor the hemoglobin concentration and oxygen saturation change of living mouse by imaging the artery and veins in a mouse tail. Materials and Methods: One mouse tail was scanned using the PCT small animal scanner at the isosbestic wavelength (796nm) to obtain its hemoglobin concentration. Immediately after the scan, the mouse was euthanized and its blood was extracted from the heart. The true hemoglobin concentration was measured using a co-oximeter. Reconstruction correction algorithm to compensate the acoustic signal loss due to the existence of bone structure in the mouse tail was developed. After the correction, the hemoglobin concentration was calculated from the PCT images and compared with co-oximeter result. Next, one mouse were immobilized in the PCT scanner. Gas with different concentrations of oxygen was given to mouse to change the oxygen saturation. PCT tail vessel spectroscopy scans were performed 15 minutes after the introduction of gas. The oxygen saturation values were then calculated to monitor the oxygen saturation change of mouse. Results: The systematic error for hemoglobin concentration measurement was less than 5% based on preliminary analysis. Same correction technique was used for oxygen saturation calculation. After correction, the oxygen saturation level change matches the oxygen volume ratio change of the introduced gas. Conclusion: This living mouse tail experiment has shown that NIR PCT-spectroscopy can be used to monitor the oxygen saturation status in living small animals.

  18. Short-term effects of air pollution on oxygen saturation in a cohort of senior adults in Steubenville, Ohio.

    Science.gov (United States)

    Luttmann-Gibson, Heike; Sarnat, Stefanie Ebelt; Suh, Helen H; Coull, Brent A; Schwartz, Joel; Zanobetti, Antonella; Gold, Diane R

    2014-02-01

    We examine whether ambient air pollution is associated with oxygen saturation in 32 elderly subjects in Steubenville, Ohio. We used linear mixed models to examine the effects of fine particulate matter less than 2.5 μm (PM(2.5)), sulfate (SO(4)(-2)), elemental carbon, and gases on median oxygen saturation. An interquartile range increase of 13.4 μg/m in PM(2.5) on the previous day was associated with a decrease of -0.18% (95% confidence interval: -0.31 to -0.06) and a 5.1 μg/m(3) interquartile range increase in SO(4)(-2) on the previous day was associated with a decrease of -0.16% (95% confidence interval: -0.27 to -0.04) in oxygen saturation during the initial 5-minute rest period of the protocol. Increased exposure to air pollution, including the nontraffic pollutant SO(4)(-2) from industrial sources, led to changes in oxygen saturation that may reflect particle-induced pulmonary inflammatory or vascular responses.

  19. Reliable monitoring of oxygen saturation via pulse oximetry: Which ...

    African Journals Online (AJOL)

    This study focuses on identifying the best site for placement of pulse oximeter probe accurate measuring of oxygen saturation. Twenty-three healthy male volunteers aged 20 to 40 years old were recruited in this study. Cold pressor test was done to stim 460 measurements of SpO2level were obtained throughout the study.

  20. Cerebral oxygen saturation and cardiac output during anaesthesia in sitting position for neurosurgical procedures: a prospective observational study.

    Science.gov (United States)

    Schramm, P; Tzanova, I; Hagen, F; Berres, M; Closhen, D; Pestel, G; Engelhard, K

    2016-10-01

    Neurosurgical operations in the dorsal cranium often require the patient to be positioned in a sitting position. This can be associated with decreased cardiac output and cerebral hypoperfusion, and possibly, inadequate cerebral oxygenation. In the present study, cerebral oxygen saturation was measured during neurosurgery in the sitting position and correlated with cardiac output. Perioperative cerebral oxygen saturation was measured continuously with two different monitors, INVOS ® and FORE-SIGHT ® . Cardiac output was measured at eight predefined time points using transoesophageal echocardiography. Forty patients were enrolled, but only 35 (20 female) were eventually operated on in the sitting position. At the first time point, the regional cerebral oxygen saturation measured with INVOS ® was 70 (sd 9)%; thereafter, it increased by 0.0187% min -1 (P<0.01). The cerebral tissue oxygen saturation measured with FORE-SIGHT ® started at 68 (sd 13)% and increased by 0.0142% min -1 (P<0.01). The mean arterial blood pressure did not change. Cardiac output was between 6.3 (sd 1.3) and 7.2 (1.8) litre min -1 at the predefined time points. Cardiac output, but not mean arterial blood pressure, showed a positive and significant correlation with cerebral oxygen saturation. During neurosurgery in the sitting position, the cerebral oxygen saturation slowly increases and, therefore, this position seems to be safe with regard to cerebral oxygen saturation. Cerebral oxygen saturation is stable because of constant CO and MAP, while the influence of CO on cerebral oxygen saturation seems to be more relevant. NCT01275898. © The Author 2016. Published by Oxford University Press on behalf of the British Journal of Anaesthesia. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  1. Oxygen general saturation after bronchography under general ...

    African Journals Online (AJOL)

    Thirty-six patients undergoing bronchography or bronchoscopy under general anaesthesia were continuously monitored by pulse oximetry for 5 hours after these procedures. Significant falls in oxygen saturation were observed in the first hour and were of most clinical relevance in patients with preexisting pulmonary ...

  2. Lung vital capacity and oxygen saturation in adults with cerebral palsy

    Directory of Open Access Journals (Sweden)

    Lampe R

    2014-12-01

    Full Text Available Renée Lampe,1,2 Tobias Blumenstein,2 Varvara Turova,2 Ana Alves-Pinto2 1Markus Würth Stiftungsprofessur, Technical University of Munich, Munich, Germany; 2Research Unit for Cerebral Palsy and Children Neuroorthopaedics of the Buhl-Strohmaier Foundation, Orthopedic Department of the Clinic “rechts der Isar” of the Technical University of Munich, Munich, Germany Background: Individuals with infantile cerebral palsy have multiple disabilities. The most conspicuous syndrome being investigated from many aspects is motor movement disorder with a spastic gait pattern. The lung function of adults with spasticity attracts less attention in the literature. This is surprising because decreased thoracic mobility and longstanding scoliosis should have an impact on lung function. With increasing age and the level of disability, individuals become susceptible to lung infections and reflux illness, and these are accompanied by increased aspiration risk. This study examined, with different methods, to what extent adults with congenital cerebral palsy and acquired spastic paresis – following traumatic brain injury – showed restriction of lung function. It also assessed the contribution of disability level on this restriction.Methods: The oxygen saturation of 46 adults with a diagnosis of cerebral palsy was measured with an oximeter. Lung vital capacity was measured with a mobile spirometer and excursion of the thorax was clinically registered. The gross motor function levels and the presence or absence of scoliosis were determined.Results: A significantly positive correlation between lung vital capacity and chest expansion was established. Both the lung vital capacity and the thorax excursion decreased with increases in gross motor function level. Oxygen saturation remained within the normal range in all persons, in spite of reduced values of the measured lung parameters. No statistically significant dependency between lung vital capacity and oxygen

  3. StoRMon: an event log analyzer for Grid Storage Element based on StoRM

    International Nuclear Information System (INIS)

    Zappi, Riccardo; Dal Pra, Stefano; Dibenedetto, Michele; Ronchieri, Elisabetta

    2011-01-01

    Managing a collaborative production Grid infrastructure requires to identify and handle every issue, which might arise, in a timely manner. Currently, the most complex problem of the data Grid infrastructure relates to the data management because of its distributed nature. To ensure that problems are quickly addressed and solved, each site should contribute to the solution providing any useful information about services that run in its administrative domain. Often Grid sites' administrators to be effective must collect, organize and examine the scattered logs events that are produced from every service and component of the Storage Element. This paper focuses on the problem of gathering the events logs on a Grid Storage Element and describes the design of a new service, called StoRMon. StoRMon will be able to collect, archive, analyze and report on events logs produced by each service of Storage Element during the execution of its tasks. The data and the processed information will be available to the site administrators by using a single contact-point to easily identify security incidents, fraudulent activity, and the operational issues mainly. The new service is applied to a Grid Storage Element characterized by StoRM, GridFTP and YAMSS, and collects the usage data of StoRM, transferring and hierarchical storage services.

  4. An efficient optimization method to improve the measuring accuracy of oxygen saturation by using triangular wave optical signal

    Science.gov (United States)

    Li, Gang; Yu, Yue; Zhang, Cui; Lin, Ling

    2017-09-01

    The oxygen saturation is one of the important parameters to evaluate human health. This paper presents an efficient optimization method that can improve the accuracy of oxygen saturation measurement, which employs an optical frequency division triangular wave signal as the excitation signal to obtain dynamic spectrum and calculate oxygen saturation. In comparison to the traditional method measured RMSE (root mean square error) of SpO2 which is 0.1705, this proposed method significantly reduced the measured RMSE which is 0.0965. It is notable that the accuracy of oxygen saturation measurement has been improved significantly. The method can simplify the circuit and bring down the demand of elements. Furthermore, it has a great reference value on improving the signal to noise ratio of other physiological signals.

  5. Monitoring mixed venous oxygen saturation in patients with obstructive shock after massive pulmonary embolism.

    Science.gov (United States)

    Krivec, Bojan; Voga, Gorazd; Podbregar, Matej

    2004-05-31

    Patients with massive pulmonary embolism and obstructive shock usually require hemodynamic stabilization and thrombolysis. Little is known about the optimal and proper use of volume infusion and vasoactive drugs, or about the titration of thrombolytic agents in patients with relative contraindication for such treatment. The aim of the study was to find the most rapidly changing hemodynamic variable to monitor and optimize the treatment of patients with obstructive shock following massive pulmonary embolism. Ten consecutive patients hospitalized in the medical intensive care unit in the community General Hospital with obstructive shock following massive pulmonary embolism were included in the prospective observational study. Heart rate, systolic arterial pressure, central venous pressure, mean pulmonary-artery pressure, cardiac index, total pulmonary vascular-resistance index, mixed venous oxygen saturation, and urine output were measured on admission and at 1, 2, 3, 4, 8, 12, and 16 hours. Patients were treated with urokinase through the distal port of a pulmonary-artery catheter. At 1 hour, mixed venous oxygen saturation, systolic arterial pressure and cardiac index were higher than their admission values (31+/-10 vs. 49+/-12%, p<0.0001; 86+/-12 vs. 105+/-17 mmHg, p<0.01; 1.5+/-0.4 vs. 1.9+/-0.7 L/min/m2, p<0.05; respectively), whereas heart rate, central venous pressure, mean pulmonary-artery pressure and urine output remained unchanged. Total pulmonary vascular-resistance index was lower than at admission (29+/-10 vs. 21+/-12 mmHg/L/min/m2, p<0.05). The relative change of mixed venous oxygen saturation at hour 1 was higher than the relative changes of all other studied variables (p<0.05). Serum lactate on admission and at 12 hours correlated to mixed venous oxygen saturation (r=-0.855, p<0.001). In obstructive shock after massive pulmonary embolism, mixed venous oxygen saturation changes more rapidly than other standard hemodynamic variables.

  6. Cerebral tissue oxygen saturation and extraction in preterm infants before and after blood transfusion

    NARCIS (Netherlands)

    van Hoften, Jacorina C. R.; Verhagen, Elise A.; Keating, Paul; ter Horst, Hendrik J.; Bos, Arend F.

    Objective Preterm infants often need red blood cell (RBC) transfusions. The aim of this study was to determine whether haemoglobin levels before transfusion were associated with regional cerebral tissue oxygen saturation (r(c)SO(2)) and fractional tissue oxygen extraction (FTOE) and whether RBC

  7. Short-term Effects of Air Pollution on Oxygen Saturation in a Cohort of Senior Adults in Steubenville, OH

    Science.gov (United States)

    Luttmann-Gibson, Heike; Sarnat, Stefanie Ebelt; Suh, Helen H.; Coull, Brent A.; Schwartz, Joel; Zanobetti, Antonella; Gold, Diane R.

    2014-01-01

    Objective We examine whether ambient air pollution is associated with oxygen saturation in 32 elderly subjects in Steubenville. Methods We used linear mixed models to examine the effects of fine particles (PM2.5), sulfate (SO42-), elemental carbon (EC), and gases on median oxygen saturation. Results An interquartile range (IQR) increase of 13.4 μg/m3 in PM2.5 on the previous day was associated with a decrease of -0.18% (95% CI: -0.31 to -0.06), and a 5.1 μg/m3 IQR increase in SO42- on the previous day was associated with a decrease of -0.16% (95% CI: -0.27 to -0.04) in oxygen saturation during the initial 5-min rest period of the protocol. Conclusions Increased exposure to air pollution, including the non-traffic pollutant SO42- from industrial sources, led to changes in oxygen saturation that may reflect particle-induced pulmonary inflammatory or vascular responses. PMID:24451609

  8. Changes in retinal venular oxygen saturation predict activity of proliferative diabetic retinopathy 3 months after panretinal photocoagulation

    DEFF Research Database (Denmark)

    Torp, Thomas Lee; Kawasaki, Ryo; Wong, Tien Yin

    2018-01-01

    .4 to -1.4), focal: -4.5% (95% CI -12.1 to 3.2)). In a multiple logistic regression model, increment in global retinal venular oxygen saturation (OR 1.30 per 1%-point increment, p=0.017) and decrement in AV oxygen saturation difference (OR 0.72 per 1%-point increment, p=0.016) at 3M independently predicted...

  9. Oxygen Saturation in the Dental Pulp of Maxillary Premolars in Different Age Groups - Part 1.

    Science.gov (United States)

    Estrela, Carlos; Serpa, Giuliano C; Alencar, Ana Helena G; Bruno, Kely F; Barletta, Fernando B; Felippe, Wilson T; Estrela, Cyntia R A; Souza, João B

    2017-01-01

    The aim of this study was to determine oxygen saturation levels in the dental pulp of maxillary premolars in different age groups. A total of 120 human maxillary premolars with normal dental pulps were selected covering the following age groups: 20-24, 25-29, 30-34, 35-39 and 40-44 years (n=24 each group). Oxygen saturation was assessed using pulse oximetry. Analysis of variance was used to assess differences in oxygen saturation levels and Tukey's test was used to identify the age groups that differed from each other. Significance was set at 0.05. Mean oxygen saturation of 120 premolars was 86.20% considering all age groups. Significantly reduced levels were found in the oldest group compared to the other groups: 40 to 44 years - 80.00% vs. 89.71, 87.67, 88.71, and 84.80% for age groups 20-24, 25-29, 30-34, 35-39 years, respectively. The mean oxygen saturation levels were similar between 20 and 39 years of age (86.20%) in the whole sample, but reduced significantly in the 40-44-year age group, suggesting that older patients present lower oxygen saturation results even in the absence of pulp tissue injury.

  10. Prediction of saturation using the carbon/oxygen log

    Energy Technology Data Exchange (ETDEWEB)

    Horner, S.C.; Sanyal, S.K.

    1984-09-01

    This project investigates the nature of Dresser-Atlas Carbon/Oxygen Log gamma ray spectra. It presents an attempt to improve the signal-to-noise ratio of the C/O and Si/Ca parameters used by Dresser-Atlas to determine oil saturation. Two techniques were developed to subtract the Compton background from the spectral data. Neither technique significantly improves the accuracy of the cased-hole prediction of oil saturation. However, it has been shown that it is possible to develop a satisfactory correlation for oil saturation on a well-by-well basis. This correlation can then be used to generate oil-in-place from the C/O and Si/Ca ratios. 17 references.

  11. Dynamic muscle O2 saturation response is impaired during major non-cardiac surgery despite goal-directed haemodynamic therapy.

    Science.gov (United States)

    Feldheiser, A; Hunsicker, O; Kaufner, L; Köhler, J; Sieglitz, H; Casans Francés, R; Wernecke, K-D; Sehouli, J; Spies, C

    2016-03-01

    Near-infrared spectroscopy combined with a vascular occlusion test (VOT) could indicate an impairment of microvascular reactivity (MVR) in septic patients by detecting changes in dynamic variables of muscle O2 saturation (StO2). However, in the perioperative context the consequences of surgical trauma on dynamic variables of muscle StO2 as indicators of MVR are still unknown. This study is a sub-analysis of a randomised controlled trial in patients with metastatic primary ovarian cancer undergoing debulking surgery, during which a goal-directed haemodynamic algorithm was applied using oesophageal Doppler. During a 3 min VOT, near-infrared spectroscopy was used to assess dynamic variables arising from changes in muscle StO2. At the beginning of surgery, values of desaturation and recovery slope were comparable to values obtained in healthy volunteers. During the course of surgery, both desaturation and recovery slope showed a gradual decrease. Concomitantly, the study population underwent a transition to a surgically induced systemic inflammatory response state shown by a gradual increase in norepinephrine administration, heart rate, and Interleukin-6, with a peak immediately after the end of surgery. Higher rates of norepinephrine and a higher heart rate were related to a faster decline in StO2 during vascular occlusion. Using near-infrared spectroscopy combined with a VOT during surgery showed a gradual deterioration of MVR in patients treated with optimal haemodynamic care. The deterioration of MVR was accompanied by the transition to a surgically induced systemic inflammatory response state. Copyright © 2015 Sociedad Española de Anestesiología, Reanimación y Terapéutica del Dolor. Publicado por Elsevier España, S.L.U. All rights reserved.

  12. Determination of optical properties, drug concentration, and tissue oxygenation in human pleural tissue before and after Photofrin-mediated photodynamic therapy

    Science.gov (United States)

    Ong, Yi Hong; Padawer-Curry, Jonah; Finlay, Jarod C.; Kim, Michele M.; Dimofte, Andreea; Cengel, Keith; Zhu, Timothy C.

    2018-02-01

    PDT efficacy depends on the concentration of photosensitizer, oxygen, and light delivery in patient tissues. In this study, we measure the in-vivo distribution of important dosimetric parameters, namely the tissue optical properties (absorption μa (λ) and scattering μs ' (λ) coefficients), photofrin concentration (cphotofrin), blood oxygen saturation (%StO2), and total hemoglobin concentration (THC), before and after PDT. We characterize the inter- and intra-patient heterogeneity of these quantities and explore how these properties change as a result of PDT treatment. The result suggests the need for real-time dosimetry during PDT to optimize the treatment condition depending on the optical and physiological properties.

  13. Neuroprotection of hyperbaric oxygen therapy in sub-acute traumatic brain injury: not by immediately improving cerebral oxygen saturation and oxygen partial pressure.

    Science.gov (United States)

    Zhou, Bao-Chun; Liu, Li-Jun; Liu, Bing

    2016-09-01

    Although hyperbaric oxygen (HBO) therapy can promote the recovery of neural function in patients who have suffered traumatic brain injury (TBI), the underlying mechanism is unclear. We hypothesized that hyperbaric oxygen treatment plays a neuroprotective role in TBI by increasing regional transcranial oxygen saturation (rSO 2 ) and oxygen partial pressure (PaO 2 ). To test this idea, we compared two groups: a control group with 20 healthy people and a treatment group with 40 TBI patients. The 40 patients were given 100% oxygen of HBO for 90 minutes. Changes in rSO 2 were measured. The controls were also examined for rSO 2 and PaO 2 , but received no treatment. rSO 2 levels in the patients did not differ significantly after treatment, but levels before and after treatment were significantly lower than those in the control group. PaO 2 levels were significantly decreased after the 30-minute HBO treatment. Our findings suggest that there is a disorder of oxygen metabolism in patients with sub-acute TBI. HBO does not immediately affect cerebral oxygen metabolism, and the underlying mechanism still needs to be studied in depth.

  14. Comparison of oxygen saturation values obtained from fingers on physically restrained or unrestrained sides of the body.

    Science.gov (United States)

    Korhan, Esra Akin; Yönt, Gülendam Hakverdioğlu; Khorshid, Leyla

    2011-01-01

    The aim of this study was to compare semiexperimentally the pulse oximetry values obtained from a finger on restrained or unrestrained sides of the body. The pulse oximeter provides a noninvasive measurement of the oxygen saturation of hemoglobin in arterial blood. One of the procedures most frequently applied to patients in intensive care units is the application of physical restraint. Circulation problems are the most important complication in patients who are physically restrained. Evaluation of oxygen saturation from body parts in which circulation is impeded or has deteriorated can cause false results. The research sample consisted of 30 hospitalized patients who participated in the study voluntarily and who were concordant with the inclusion criteria of the study. Patient information and patient follow-up forms were used for data collection. Pulse oximetry values were measured simultaneously using OxiMax Nellcor finger sensors from fingers on the restrained and unrestrained sides of the body. Numeric and percentile distributions were used in evaluating the sociodemographic properties of patients. A significant difference was found between the oxygen saturation values obtained from a finger of an arm that had been physically restrained and a finger of an arm that had not been physically restrained. The mean oxygen saturation value measured from a finger of an arm that had been physically restrained was found to be 93.40 (SD, 2.97), and the mean oxygen saturation value measured from a finger of an arm that had not been physically restrained was found to be 95.53 (SD, 2.38). The results of this study indicate that nurses should use a finger of an arm that is not physically restrained when evaluating oxygen saturation values to evaluate them correctly.

  15. Oxygen breathing accelerates decompression from saturation at 40 msw in 70-kg swine.

    Science.gov (United States)

    Petersen, Kyle; Soutiere, Shawn E; Tucker, Kathryn E; Dainer, Hugh M; Mahon, Richard T

    2010-07-01

    Submarine disaster survivors can be transferred from a disabled submarine at a pressure of 40 meters of seawater (msw) to a new rescue vehicle; however, they face an inherently risky surface interval before recompression and an enormous decompression obligation due to a high likelihood of saturation. The goal was to design a safe decompression protocol using oxygen breathing and a trial-and-error methodology. We hypothesized that depth, timing, and duration of oxygen breathing during decompression from saturation play a role to mitigate decompression outcomes. Yorkshire swine (67-75 kg), compressed to 40 msw for 22 h, underwent one of three accelerated decompression profiles: (1) 13.3 h staged air decompression to 18 msw, followed by 1 h oxygen breathing, then dropout; (2) direct decompression to 18 msw followed by 1 h oxygen breathing then dropout; and (3) 1 h oxygen prebreathe at 40 msw followed by 1 h mixed gas breathing at 26 msw, 1 h oxygen breathing at 18 msw, and 1 h ascent breathing oxygen. Animals underwent 2-h observation for signs of DCS. Profile 1 (14.3 h total) resulted in no deaths, no Type II DCS, and 20% Type I DCS. Profile 2 (2.1 h total) resulted in 13% death, 50% Type II DCS, and 75% Type I DCS. Profile 3 (4.5 h total) resulted in 14% death, 21% Type II DCS, and 57% Type I DCS. No oxygen associated seizures occurred. Profile 1 performed best, shortening decompression with no death or severe DCS, yet it may still exceed emergency operational utility in an actual submarine rescue.

  16. Noninvasive optical quantification of absolute blood flow, blood oxygenation, and oxygen consumption rate in exercising skeletal muscle

    Science.gov (United States)

    Gurley, Katelyn; Shang, Yu; Yu, Guoqiang

    2012-07-01

    This study investigates a method using novel hybrid diffuse optical spectroscopies [near-infrared spectroscopy (NIRS) and diffuse correlation spectroscopy (DCS)] to obtain continuous, noninvasive measurement of absolute blood flow (BF), blood oxygenation, and oxygen consumption rate (\\Vdot O2) in exercising skeletal muscle. Healthy subjects (n=9) performed a handgrip exercise to increase BF and \\Vdot O2 in forearm flexor muscles, while a hybrid optical probe on the skin surface directly monitored oxy-, deoxy-, and total hemoglobin concentrations ([HbO2], [Hb], and THC), tissue oxygen saturation (StO2), relative BF (rBF), and relative oxygen consumption rate (r\\Vdot O2). The rBF and r\\Vdot O2 signals were calibrated with absolute baseline BF and \\Vdot O2 obtained through venous and arterial occlusions, respectively. Known problems with muscle-fiber motion artifacts in optical measurements during exercise were mitigated using a novel gating algorithm that determined muscle contraction status based on control signals from a dynamometer. Results were consistent with previous findings in the literature. This study supports the application of NIRS/DCS technology to quantitatively evaluate hemodynamic and metabolic parameters in exercising skeletal muscle and holds promise for improving diagnosis and treatment evaluation for patients suffering from diseases affecting skeletal muscle and advancing fundamental understanding of muscle and exercise physiology.

  17. The CMS experiment workflows on StoRM based storage at Tier-1 and Tier-2 centers

    International Nuclear Information System (INIS)

    Bonacorsi, D; Bartolome, I Cabrillo; Matorras, F; Gonzalez Caballero, I; Sartirana, A

    2010-01-01

    Approaching LHC data taking, the CMS experiment is deploying, commissioning and operating the building tools of its grid-based computing infrastructure. The commissioning program includes testing, deployment and operation of various storage solutions to support the computing workflows of the experiment. Recently, some of the Tier-1 and Tier-2 centers supporting the collaboration have started to deploy StoRM based storage systems. These are POSIX-based disk storage systems on top of which StoRM implements the Storage Resource Manager (SRM) version 2 interface allowing for a standard-based access from the Grid. In this notes we briefly describe the experience so far achieved at the CNAF Tier-1 center and at the IFCA Tier-2 center.

  18. Effects of spinal immobilization at a 20° angle on cerebral oxygen saturations measured by INVOS™.

    Science.gov (United States)

    Aksel, Gökhan

    2018-01-01

    In this study, we aimed to investigate whether performing the immobilization at 20° instead of 0° changes cerebral oxygenation. 33 volunteers were put in a hard cervical collar and backboard at 0° and immobilized for 30min. The cerebral oxygen saturations of the volunteers were measured at 1, 5, and 30min after the start of the procedure (Group 1). The volunteers were asked to return the day after the Group 1 procedure but at the same time. Serial cerebral oxygen saturations were obtained at the same time intervals as in Group 1, but for Group 2, the backboard was set to 20°. When the cerebral oxygen saturations of the two groups were compared, there was a slight decrease when the backboard position was changed from 0° to 20°, but it was not statistically significant (P=0.220 and P=0.768, respectively). The results revealed that immobilizing the patients with a spinal backboard at 20° instead of 0° did not alter the cerebral oxygen saturations. Our study results revealed that spinal immobilization at 20°, which was a new suggestion for spinal immobilization following a report that this position reduced the decrease in pulmonary function secondary to spinal immobilization, did not alter the cerebral oxygenation, so this suggestion is safe at least from the standpoint of cerebral oxygenation. Copyright © 2017 Elsevier Inc. All rights reserved.

  19. Developmental Effects Determine Submaximal Arterial Oxygen Saturation in Peruvian Quechua.

    Science.gov (United States)

    Kiyamu, Melisa; León-Velarde, Fabiola; Rivera-Chira, María; Elías, Gianpietro; Brutsaert, Tom D

    2015-06-01

    Kiyamu, Melisa, Fabiola León-Velarde, María Rivera-Chira, Gianpietro Elías, and Tom D. Brutsaert. Developmental effects determine submaximal arterial oxygen saturation in Peruvian Quechua. High Alt Med Biol 16, 138-146, 2015.--Andean high altitude natives show higher arterial oxygen saturation (Sao(2)) during exercise in hypoxia, compared to acclimatized sojourners. In order to evaluate the effects of life-long exposure to high altitude on Sao(2), we studied two groups of well-matched, self-identified Peruvian Quechua natives who differed in their developmental exposure to hypoxia before and after a 2-month training period. Male and female volunteers (18-35 years) were recruited in Lima, Peru (150 m). The two groups were: a) Individuals who were born and raised at sea-level (BSL, n=34) and b) Individuals who were born and raised at high altitude (BHA, n=32), but who migrated to sea-level as adults (>16 years old). Exercise testing was conducted using a submaximal exercise protocol in normobaric hypoxia in Lima (BP=750 mmHg, Fio(2)=0.12), in order to measure Sao(2) (%), ventilation (VE L/min) and oxygen consumption (Vo(2), L/min). Repeated-measures ANOVA, controlling for VE/VO(2) (L/min) and sex during the submaximal protocol showed that BHA maintained higher Sao(2) (%) compared to BSL at all workloads before (p=0.005) and after training (p=0.017). As expected, both groups showed a decrease in Sao(2) (%) (p<0.001), as workload increased. Resting Sao(2) levels were not found to be different between groups. The results suggest that developmental exposure to altitude contributes to the maintenance of higher Sao(2) levels during submaximal exercise at hypoxia.

  20. Independent component analysis applied to pulse oximetry in the estimation of the arterial oxygen saturation (SpO2) - a comparative study

    DEFF Research Database (Denmark)

    Jensen, Thomas; Duun, Sune Bro; Larsen, Jan

    2009-01-01

    We examine various independent component analysis (ICA) digital signal processing algorithms for estimating the arterial oxygen saturation (SpO2) as measured by a reflective pulse oximeter. The ICA algorithms examined are FastICA, Maximum Likelihood ICA (ICAML), Molgedey and Schuster ICA (ICAMS......), and Mean Field ICA (ICAMF). The signal processing includes pre-processing bandpass filtering to eliminate noise, and post-processing by calculating the SpO2. The algorithms are compared to the commercial state-of-the-art algorithm Discrete Saturation Transform (DST) by Masimo Corporation...

  1. Compliance in oxygen saturation targeting in preterm infants : a systematic review

    NARCIS (Netherlands)

    van Zanten, Henriëtte A; Tan, Ratna N G B; van den Hoogen, Agnes; Lopriore, Enrico; te Pas, Arjan B

    2015-01-01

    UNLABELLED: During oxygen therapy in preterm infants, targeting oxygen saturation is important for avoiding hypoxaemia and hyperoxaemia, but this can be very difficult and challenging for neonatal nurses. We systematically reviewed the qualitative and quantitative studies investigating the

  2. Optical Modulation of BST/STO Thin Films in the Terahertz Range

    Science.gov (United States)

    Zeng, Ying; Shi, Songjie; Zhou, Ling; Ling, Furi; Yao, Jianquan

    2018-04-01

    The {Ba}_{0.7} {Sr}_{0.3} {TiO}3 (BST) thin film (30.3 nm) deposited on a {SrTiO}3 (STO) film/silicon substrate sample was modulated by 532 nm continuous-wave laser in the range of 0.2-1 THz at room temperature. The refractive index variation was observed to linearly increase at the highest 3.48 for 0.5 THz with the pump power increasing to 400 mW. It was also found that the BST/STO sample had a larger refractive index variation and was more sensitive to the external optical field than a BST monolayer due to the epitaxial strain induced by the STO film. The electric displacement-electric field loops results revealed that the increasing spontaneous polarization with the STO film that was induced was responsible for the larger refractive index variation of the BST/STO sample. In addition, the real and imaginary part of the permittivity were observed increasing along with the external field increasing, due to the soft mode hardening.

  3. Tissue oxygenation as a target for goal-directed therapy in high-risk surgery : a pilot study

    NARCIS (Netherlands)

    van Beest, Paul A.; Vos, Jaap Jan; Poterman, Marieke; Kalmar, Alain F.; Scheeren, Thomas W. L.

    2014-01-01

    Background:  Tissue hypoperfusion occurs frequently during surgery and may contribute to postoperative organ dysfunction. There is a need for perioperative treatment protocols aiming at improving tissue oxygenation (StO(2)). We hypothesised that intra-operative optimisation of StO(2) improves tissue

  4. Retinal oxygen saturation in relation to retinal thickness in diabetic macular edema

    DEFF Research Database (Denmark)

    Blindbæk, Søren Leer; Peto, Tunde; Grauslund, Jakob

    to retinal thickness in patients with diabetic macular edema (DME). Methods: We included 18 patients with DME that all had central retinal thickness (CRT) >300 µm and were free of active proliferative diabetic retinopathy. Optical coherence tomography (Topcon 3D OCT-2000 spectral domain OCT) was used...... for paracentral edema, the oxygen saturation in the upper and lower temporal arcade branches were compared to the corresponding upper and lower subfield thickness. Spearman’s rank was used to calculate correlation coefficients between CRT and retinal oximetry. Results: Median age and duration of diabetes was 59....... 92.3%, p=0.52). We found no correlation between CRT and retinal oxygen saturation, even when accounting for paracentral edema (p>0.05). Furthermore, there was no difference in retinal oxygen saturation between the macular hemisphere that was more or less affected by DME (p>0.05). Conclusion: Patients...

  5. Optimization measurement of muscle oxygen saturation under isometric studies using FNIRS

    Science.gov (United States)

    Halim, A. A. A.; Laili, M. H.; Salikin, M. S.; Rusop, M.

    2018-05-01

    Development of functional near infrared spectroscopy (fNIRS) technologies has advanced quantification signal using multiple wavelength and detector to investigate hemodynamic response in human muscle. These non-invasive technologies have been widely used to solve the propagation of light inside the tissues including the absorption, scattering coefficient and to quantify the oxygenation level of haemoglobin and myoglobin in human muscle. The goal of this paper is to optimize the measurement of muscle oxygen saturation during isometric exercise using functional near infrared spectroscopy (fNIRS). The experiment was carried out on 15 sedentary healthy male volunteers. All volunteers are required to perform an isometric exercise at three assessment of muscular fatigue's level on flexor digitalis (FDS) muscle in the human forearm using fNIRS. The slopes of the signals have been highlighted to evaluate the muscle oxygen saturation of regional muscle fatigue. As a result, oxygen saturation slope from 10% exercise showed steeper than the first assessment at 30%-50% of fatigues level. The hemodynamic signal response showed significant value (p=0.04) at all three assessment of muscular fatigue's level which produce a p-value (p<0.05) measured by fNIRS. Thus, this highlighted parameter could be used to estimate fatigue's level of human and could open other possibilities to study muscle performance diagnosis.

  6. SU-E-T-326: The Oxygen Saturation (SO2) and Breath-Holding Time Variation Applied Active Breathing Control (ABC)

    Energy Technology Data Exchange (ETDEWEB)

    Gong, G; Yin, Y [Shandong Cancer Hospital, Jinan, Shandong (China)

    2014-06-01

    Purpose: To study the oxygen saturation (SO2) and breath-holding time variation applied active breathing control (ABC) in radiotherapy of tumor. Methods: 24 volunteers were involved in our trials, and they all did breath-holding motion assisted by ELEKTA Active Breathing Coordinator 2.0 for 10 times respectively. And the patient monitor was used to observe the oxygen saturation (SO2) variation. The variation of SO2, and length of breath-holding time and the time for recovering to the initial value of SO2 were recorded and analyzed. Results: (1) The volunteers were divided into two groups according to the SO2 variation in breath-holding: A group, 14 cases whose SO2 reduction were more than 2% (initial value was 97% to 99%, while termination value was 91% to 96%); B group, 10 cases were less than 2% in breath-holding without inhaling oxygen. (2) The interfraction breath holding time varied from 8 to 20s for A group compared to the first breath-holding time, and for B group varied from 4 to 14s. (3) The breathing holding time of B group prolonged mean 8s, compared to A group. (4) The time for restoring to the initial value of SO2 was from 10s to 30s. And the breath-holding time shortened obviously for patients whose SO2 did not recover to normal. Conclusion: It is very obvious that the SO2 reduction in breath-holding associated with ABC for partial people. It is necessary to check the SO2 variation in breath training, and enough time should be given to recover SO2.

  7. Validation of NIRS in measuring tissue hemoglobin concentration and oxygen saturation on ex vivo and isolated limb models

    Science.gov (United States)

    Xu, Xiaorong; Zhu, Wen; Padival, Vikram; Xia, Mengna; Cheng, Xuefeng; Bush, Robin; Christenson, Linda; Chan, Tim; Doherty, Tim; Iatridis, Angelo

    2003-07-01

    Photonify"s tissue spectrometer uses Near-Infrared Spectroscopy for real-time, noninvasive measurement of hemoglobin concentration and oxygen saturation [SO2] of biological tissues. The technology was validated by a series of ex vivo and animal studies. In the ex vivo experiment, a close loop blood circulation system was built, precisely controlling the oxygen saturation and the hemoglobin concentration of a liquid phantom. Photonify"s tissue spectrometer was placed on the surface of the liquid phantom for real time measurement and compared with a gas analyzer, considered the gold standard to measure oxygen saturation and hemoglobin concentration. In the animal experiment, the right hind limb of each dog accepted onto the study was surgically removed. The limb was kept viable by connecting the femoral vein and artery to a blood-primed extracorporeal circuit. Different concentrations of hemoglobin were obtained by adding designated amount of saline solution into the perfusion circuit. Photonify"s tissue spectrometers measured oxygen saturation and hemoglobin concentration at various locations on the limb and compared with gas analyzer results. The test results demonstrated that Photonify"s tissue spectrometers were able to detect the relative changes in tissue oxygen saturation and hemoglobin concentration with a high linear correlation compared to the gas analyzer

  8. Macular Retinal Vessel Oxygen Saturation Elevation in Chinese Central Serous Chorioretinopathy

    Directory of Open Access Journals (Sweden)

    Cheng Li

    2017-01-01

    Full Text Available Purpose. To evaluate the retinal vessel oxygen saturation in central serous chorioretinopathy (CSC cases among the Chinese. Methods. Relative oxygen saturation of retinal blood vessels was measured in 33 Chinese patients with single-eye CSC using the Oxymap T1 retinal oximeter. The contralateral eyes were the control. The mean saturation of the retinal arteriole (AS and venule (VS, arteriovenous difference (AVS, and arteriole and venule diameters (AD, VD was analyzed in the optic disc area and macular region. Results. In the optic disc area, the inferotemporal quadrant (TI AS (93.2 ± 10.2% and inferonasal quadrant (NI VS (61.3 ± 7.3% were higher in the affected eyes than in the contralateral eyes (88.7 ± 7.7% and 56.9 ± 6.5% and AVS in NI (36.7 ± 10.4% decreased compared to the contralateral eyes (41.5 ± 11.2%. The VD in TI was expanded (19.9 ± 2.5 pixels versus 18.1 ± 3.4 pixels. Around the macular region, AS was 93.6 ± 7.6%, higher than in the contralateral eyes (89.5 ± 6.3%. No other significant changes were found. Conclusions. AS increased in the TI, and VS decreased in the NI in the eyes with CSC. In addition, AS also increased around the macular region, suggesting that these are contributors to CSC pathophysiology.

  9. [Near-infrared spectroscopy in sepsis therapy : predictor of a low central venous oxygen saturation].

    Science.gov (United States)

    Lichtenstern, C; Koch, C; Röhrig, R; Rosengarten, B; Henrich, M; Weigand, M A

    2012-10-01

    Early goal-directed hemodynamic optimization has become a cornerstone of sepsis therapy. One major defined goal is to achieve adequate central venous oxygen saturation (SO(2)). This study aimed to investigate the correlation between central venous SO(2) and frontal cerebral near-infrared spectroscopy (NIRS) measurement in patients with severe sepsis and septic shock. The NIRS method provides non-invasive measurement of regional oxygen saturation (rSO(2)) in tissues approximately 2 cm below the optical NIRS sensors which depends on arterial, capillary and venous blood. Thus this system gives site-specific real-time data about the balance of oxygen supply and demand. This was a secondary analysis from a prospective study of surgical intensive care (ICU) patients in the early phase of severe sepsis or septic shock. Bilateral cerebral rSO(2), central venous SO(2), arterial oxygen saturation (S(a)O(2)) and other surrogate parameters of oxygen supply, such as hemoglobin, partial pressure of oxygen and oxygen content in arterial blood were recorded. A total of 16 ICU patients (4 women, median age 65.5 years) were included in the study. As sepsis focus an intra-abdominal infection was detected in 62.5 % of patients, severe pneumonia was determined in 31.3 % and skin and soft tissue infections were recognized in 12.5 %. At study inclusion 50 % of patients had septic shock, the median sequential organ failure assessment (SOFA) score was 10.2 (interquartile range 5.25-8.75) and the median acute physiology and chronic health evaluation II (APACHE II) score was 26 (range 23.25-29.75). Mortality at day 28 was 37.5 %. Minimum rSO(2) (median 58) and right-sided rSO(2) (median 58) values showed a significant correlation in the analysis of receiver operating characteristics (area under the curve 0.844, p= 0.045). A central venous SO(2)< 70 % was indicated by rSO(2)< 56.5 with sensitivity and specificity of 75 % and 100 %, respectively. Cerebral NIRS could provide a fast and easily

  10. In vivo integrated photoacoustic and confocal microscopy of hemoglobin oxygen saturation and oxygen partial pressure.

    Science.gov (United States)

    Wang, Yu; Hu, Song; Maslov, Konstantin; Zhang, Yu; Xia, Younan; Wang, Lihong V

    2011-04-01

    We developed dual-modality microscope integrating photoacoustic microscopy (PAM) and fluorescence confocal microscopy (FCM) to noninvasively image hemoglobin oxygen saturation (sO₂) and oxygen partial pressure (pO₂) in vivo in single blood vessels with high spatial resolution. While PAM measures sO₂ by imaging hemoglobin optical absorption at two wavelengths, FCM quantifies pO₂ using phosphorescence quenching. The variations of sO₂ and pO₂ values in multiple orders of vessel branches under hyperoxic (100% oxygen) and normoxic (21% oxygen) conditions correlate well with the oxygen-hemoglobin dissociation curve. In addition, the total concentration of hemoglobin is imaged by PAM at an isosbestic wavelength.

  11. Nocturnal oxygen saturation profiles of healthy term infants.

    Science.gov (United States)

    Terrill, Philip Ian; Dakin, Carolyn; Hughes, Ian; Yuill, Maggie; Parsley, Chloe

    2015-01-01

    Pulse oximetry is used extensively in hospital and home settings to measure arterial oxygen saturation (SpO2). Interpretation of the trend and range of SpO2 values observed in infants is currently limited by a lack of reference ranges using current devices, and may be augmented by development of cumulative frequency (CF) reference-curves. This study aims to provide reference oxygen saturation values from a prospective longitudinal cohort of healthy infants. Prospective longitudinal cohort study. Sleep-laboratory. 34 healthy term infants were enrolled, and studied at 2 weeks, 3, 6, 12 and 24 months of age (N=30, 25, 27, 26, 20, respectively). Full overnight polysomnography, including 2 s averaging pulse oximetry (Masimo Radical). Summary SpO2 statistics (mean, median, 5th and 10th percentiles) and SpO2 CF plots were calculated for each recording. CF reference-curves were then generated for each study age. Analyses were repeated with sleep-state stratifications and inclusion of manual artefact removal. Median nocturnal SpO2 values ranged between 98% and 99% over the first 2 years of life and the CF reference-curves shift right by 1% between 2 weeks and 3 months. CF reference-curves did not change with manual artefact removal during sleep and did not vary between rapid eye movement (REM) and non-REM sleep. Manual artefact removal did significantly change summary statistics and CF reference-curves during wake. SpO2 CF curves provide an intuitive visual tool for evaluating whether an individual's nocturnal SpO2 distribution falls within the range of healthy age-matched infants, thereby complementing summary statistics in the interpretation of extended oximetry recordings in infants. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  12. Improvement in retinal venous oxygen saturation after panretinal photocoagulation is predictive of progression of proliferative diabetic retinopathy

    DEFF Research Database (Denmark)

    Torp, Thomas Lee; Kawasaki, Ryo; Wong, Tien Yin

    blood pressure was 152/84mmHg. Retinal arterial and venous saturation was 96.7% and 67.4%, respectively. Patients in Group 1 and 2 did not differ in baseline retinal arterial and venous oxygen saturation, number of laser spots delivered, total laser energy delivered, or change in retinal arterial oxygen...... patients with diagnosed PDR were included. We performed wide-field fluorescein angiography (WFA) (Optomap; Optos PLC., Dunfermline, Scotland, UK) and retinal oximetry (Oxymap model T1; Oxymap, software version 2.4.2, Reykjavik, Iceland) at baseline and three months after PRP by a navigated laser (NAVILAS...

  13. Ugniakuras archajinio gyvenamojo būsto struktūroje

    Directory of Open Access Journals (Sweden)

    Karolina Buivydaitė

    2011-06-01

    Full Text Available Nagrinėjami nuo seniausių laikų egzistavę archajinio būsto ugniakurai, kurie buvo aptikti dabartinės Lietuvos teritorijoje. Nors ugniakuras žmogaus gyvenamojoje aplinkoje buvo ir tebėra vienas esmingiausių būties komponentų ir būsto struktūros elementas, iki šiol mūsų architektūrologijoje nebuvo specialiai tiriamas. Įvairių nesusistemintų duomenų apie gyvenamojo būsto ugniakurus Lietuvoje yra archeologų, istorikų, mitologų, etnologų moksliniuose darbuose. Negausių ir gana fragmentiškų žinių šia tema esti keliuose architektūros istorijai skirtuose tekstuose. Todėl bandant užpildyti minėtą spragą, parengtas šis straipsnis. Jame aptariamas ankstyviausias būsto ugniakuro istorinės raidos etapas, prasidedantis išvien su stacionaraus būsto statybos pradžia.Straipsnis lietuvių kalba

  14. LSMO-STO(110) multilayered structure grown by metalorganic aerosol deposition

    International Nuclear Information System (INIS)

    Sapoval, Oleg; Belenchuk, Alexander; Canter, Valeriu; Zasavitsky, Efim; Moshnyaga, Vasily

    2013-01-01

    La 0.67 Sr 0.33 MnO 3 -SrTiO 3 multilayered structure was grown on SrTiO 3 (110) substrates by metalorganic aerosol deposition technique. The crystal structure was examined by X-ray analysis including simulation of diffraction and reflection patterns. The magneto transport properties of superlattice are presented. The critical thickness of (110)-oriented LSMO layers is lower than 7 perovskite unite cells. The oxygen stoichiometry provided due to high gas pressure conditions is responsible for reducing of critical thickness of LSMO layers at LSMO-STO(110) interfaces. (authors)

  15. Non-invasive tissue oximetry following unilateral DIEP-flap reconstruction: A pilot evaluation

    Directory of Open Access Journals (Sweden)

    N.P.A. Vranken

    2017-06-01

    Conclusion: Continuous non-invasive tissue oxygen saturation is suitable for postoperative monitoring of DIEP-flaps, and StO2 pattern may aid in early identification of vascular compromise in DIEP-flaps.

  16. The Effect of Non-nutritive Sucking on Transcutaneous Oxygen Saturation in Neonates under the Nasal Continuous Positive Airway Pressure (CPAP

    Directory of Open Access Journals (Sweden)

    Mousa Ahmadpour-kacho

    2017-03-01

    Full Text Available BackgroundSeveral beneficial effects of non-nutritive sucking in infants, including the physiological stability, relaxation, better transition from tube feeding to oral feeding have been reported. But its effect on oxygen saturation in neonates under the Nasal Continuous Positive Airway Pressure (NCPAPو (is not so clear. This study aimed to investigate the effects of non-nutritive sucking on transcutaneous oxygen saturation levels of neonates treated with NCPAP.Materials and MethodsThis quasi-experimental study was done on 25 preterm neonates, hospitalized with a diagnosis of respiratory distress, required NCPAP, in the neonatal intensive care unit (NICU at the Ayatollah Rouhani Hospital and Babol Clinic, North of Iran. Non-nutritive sucking was elicited by a standard pacifier appropriate to their age one hour a day, and the mean oxygen saturation was measured before and after intervention by cardiopulmonary monitoring (Saadat Co., Iran. Data analyzed using SPSS-18.0 software.ResultsIn the 25 cases studied, the mean oxygen saturation values ​​before performing non-nutritive sucking was 96.31±2.88%, which was changed to 98.35±1.6% after intervention, and this increase was statistically significant (P = 0.004.Results showed that the gender, birth weight and gestational age of neonates had no effect on mean Blood oxygen saturation (SpO2level.ConclusionAccording to the results, using the non-nutritive sucking in premature neonates under the NCPAP, can improve oxygenation.

  17. Central venous oxygen saturation in septic shock - a marker of cardiac output, microvascular shunting and/or dysoxia?

    DEFF Research Database (Denmark)

    Haase, Nicolai; Perner, Anders

    2011-01-01

    Shock therapy aims at increasing central venous oxygen saturation (ScvO2), which is a marker of inadequate oxygen delivery. In this issue of Critical Care, Textoris and colleagues challenge this notion by reporting that high levels of ScvO2 are associated with mortality in patients with septic sh...

  18. Growth of the microalgae Neochloris oleoabundans at high partial oxygen pressures and sub-saturating light intensity

    NARCIS (Netherlands)

    Sousa, C.A.; Winter, de L.; Janssen, M.G.J.; Vermue, M.H.; Wijffels, R.H.

    2012-01-01

    The effect of partial oxygen pressure on growth of Neochloris oleoabundans was studied at sub-saturating light intensity in a fully-controlled stirred tank photobioreactor. At the three partial oxygen pressures tested (PO2=0.24; 0.63; 0.84 bar), the specific growth rate was 1.38; 1.36 and 1.06

  19. Changes in retinal venular oxygen saturation predict activity of proliferative diabetic retinopathy 3 months after panretinal photocoagulation.

    Science.gov (United States)

    Torp, Thomas Lee; Kawasaki, Ryo; Wong, Tien Yin; Peto, Tunde; Grauslund, Jakob

    2018-03-01

    Proliferative diabetic retinopathy (PDR) is a severe blinding condition. We investigated whether retinal metabolism, measured by retinal oximetry, may predict PDR activity after panretinal laser photocoagulation (PRP). We performed a prospective, interventional, clinical study of patients with treatment-naive PDR. Wide-field fluorescein angiography (OPTOS, Optomap) and global and focal retinal oximetry (Oxymap T1) were performed at baseline (BL), and 3 months (3M) after PRP. Angiographic findings were used to divide patients according to progression or non-progression of PDR after PRP. We evaluated differences in global and focal retinal oxygen saturation between patients with and without progression of PDR after PRP treatment. We included 45 eyes of 37 patients (median age and duration of diabetes were 51.6 and 20 years). Eyes with progression of PDR developed a higher retinal venous oxygen saturation than eyes with non-progression at 3M (global: +5.9% (95% CI -1.5 to 12.9), focal: +5.4%, (95% CI -4.1 to 14.8)). Likewise, progression of PDR was associated with a lower arteriovenular (AV) oxygen difference between BL and 3M (global: -6.1%, (95% CI -13.4 to -1.4), focal: -4.5% (95% CI -12.1 to 3.2)). In a multiple logistic regression model, increment in global retinal venular oxygen saturation (OR 1.30 per 1%-point increment, p=0.017) and decrement in AV oxygen saturation difference (OR 0.72 per 1%-point increment, p=0.016) at 3M independently predicted progression of PDR. Development of higher retinal venular and lower AV global oxygen saturation independently predicts progression of PDR despite standard PRP and might be a potential non-invasive marker of angiogenic disease activity. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  20. Design of pulse oximetry signal based on personal computer for detection oxygen saturation

    International Nuclear Information System (INIS)

    Umi Salamah; Margi Sasono

    2015-01-01

    The lack or excess of oxygen in the blood will cause healthy and body system disorder. At certain level, the disease can lead to death. For that reason, the information about oxygen saturation in blood becomes important to be identified. One of the devices used to monitor the blood oxygen saturation is pulse oximetry. This research attempt to designed Pulse Oximetry based on personal computer using red LED and infrared as its light source, while the light sensor using photodiode. The designed Pulse Oximetry is a non-invasive instrumentation which LED drivers is placed on the fingertips. The LED light goes through the finger will be a signal that is fed to the photodiode and will be converted into digital signals by ADC (Analog to Digital Converter) and will be processed further by a personal computer to display the pulse oximetry graphics. This study uses Delphi 7, Microsoft Excel, and Mt Lab as its software.This designed pulse oximetry has been tested in two peoples: sample A, male 38 years; and sample B, a woman 23 years old. Oxygen saturation of sample A is 80.75, while the sample B is 90.75. (author)

  1. Blood oxygen saturation determined by transmission spectrophotometry of hemolyzed blood samples

    Science.gov (United States)

    Malik, W. M.

    1967-01-01

    Use of the Lambert-Beer Transmission Law determines blood oxygen saturation of hemolyzed blood samples. This simplified method is based on the difference in optical absorption properties of hemoglobin and oxyhemoglobin.

  2. An in vivo evaluation of the change in the pulpal oxygen saturation after administration of preoperative anxiolytics and local anesthesia

    Directory of Open Access Journals (Sweden)

    Krishna P. Shetty

    2016-03-01

    Full Text Available Background. Given the influence of systemic blood pressure on pulpal blood flow, anxiolytics prescribed may alter the pulpal blood flow along with the local anesthetic solution containing a vasoconstrictor. This study evaluated the impact of preoperative anxiolytics and vasoconstrictors in local anesthetic agents on pulpal oxygen saturation. Methods. Thirty anxious young healthy individuals with a mean age of 24 years were randomly selected using the Corah’s Dental Anxiety Scale (DAS. After checking the vital signs the initial pulpal oxygen saturation (initial SpO2 was measured using a pulse oximeter. Oral midzolam was administered at a dose of 7.5 mg. After 30 min, the vital signs were monitored and the pulpal oxygen saturation (anxiolytic SpO2 was measured. A total of 1.5 mL of 2% lidocaine with 1:200000 epinephrine was administered as buccal infiltration anesthesia and 10 min the final pulpal oxygen saturation (L.A SpO2 was measured. Results. The mean initial (SpO2 was 96.37% which significantly decreased to 90.76% (SpO2 after the administration of the anxiolytic agent. This drop was later accentuated to 85.17% (SpO2 after administration of local anesthetic solution. Statistical significance was set at P<0.0001. Conclusion. High concentrations of irritants may permeate dentin due to a considerable decrease in the pulpal blood flow from crown or cavity preparation. Therefore, maintaining optimal blood flow during restorative procedures may prevent pulpal injury.

  3. The Choroidal Eye Oximeter - An instrument for measuring oxygen saturation of choroidal blood in vivo

    Science.gov (United States)

    Laing, R. A.; Danisch, L. A.; Young, L. R.

    1975-01-01

    The Choroidal Eye Oximeter is an electro-optical instrument that noninvasively measures the oxygen saturation of choroidal blood in the back of the human eye by a spectrophotometric method. Since choroidal blood is characteristic of blood which is supplied to the brain, the Choroidal Eye Oximeter can be used to monitor the amount of oxygen which is supplied to the brain under varying external conditions. The instrument consists of two basic systems: the optical system and the electronic system. The optical system produces a suitable bi-chromatic beam of light, reflects this beam from the fundus of the subject's eye, and onto a low-noise photodetector. The electronic system amplifies the weak composite signal from the photodetector, computes the average oxygen saturation from the area of the fundus that was sampled, and displays the value of the computed oxygen saturation on a panel meter.

  4. Degradation of phospholipids under different types of irradiation and varying oxygen saturation

    Czech Academy of Sciences Publication Activity Database

    Vyšín, Luděk; Tomanová, K.; Pavelková, T.; Wagner, Richard; Davídková, Marie; Múčka, V.; Čuba, V.; Juha, Libor

    2017-01-01

    Roč. 56, č. 3 (2017), s. 241-247 ISSN 0301-634X R&D Projects: GA ČR GA13-28721S; GA ČR(CZ) GBP108/12/G108; GA MŠk LM2015056 Institutional support: RVO:68378271 ; RVO:61389005 Keywords : lipid peroxidation * DOPC * gamma rays * eectrons * protons * oxygen saturation Subject RIV: BO - Biophysics OBOR OECD: Biophysics Impact factor: 2.398, year: 2016

  5. The effect of tourniquet deflation on hemodynamics and regional cerebral oxygen saturation in aged patients undergoing total knee replacement surgery.

    Science.gov (United States)

    Song, Inkyung; Kim, Dong Yeon; Kim, Youn Jin

    2012-11-01

    Inflation and deflation of a pneumatic tourniquet used in total knee replacement surgery induces various changes in patient's hemodynamic and metabolic status, which may result in serious complications, especially in aged patients. Near-infrared spectroscopy (NIRS) is a monitoring device designed to estimate the regional cerebral oxygen saturation. We evaluated the effect of tourniquet deflation on hemodynamics and regional cerebral oxygen saturation in aged patients undergoing total knee replacement surgery, using NIRS. Twenty-eight American Society of Anesthesiologists physical status I or II patients, over the age of sixty-five years undergoing total knee replacement surgery, were included. Under general anesthesia, the mean arterial pressure (MAP), heart rate (HR), cardiac output (CO), stroke volume (SV), and regional cerebral oxygen saturation (rSO(2)) were recorded before induction of anesthesia and every 2 min after tourniquet deflation for 20 min. Arterial blood gas analysis was performed 5 min before, in addition to 0, and 10 min after tourniquet deflation. The decrease of rSO(2) was not significant during 20-min deflation period. MAP, CO and SV showed significant decrease during 2 to 12, 4 to 6 and 2 to 6-min period after tourniquet deflation, respectively (P deflation caused significant changes in hemodynamic and metabolic status, but not in regional cerebral oxygen saturation. It is recommended to monitor neurologic status, as well as hemodynamic and metabolic status to avoid serious complications, especially in aged patients.

  6. Analysis of Distinct Roles of CaMKK Isoforms Using STO-609-Resistant Mutants in Living Cells.

    Science.gov (United States)

    Fujiwara, Yuya; Hiraoka, Yuri; Fujimoto, Tomohito; Kanayama, Naoki; Magari, Masaki; Tokumitsu, Hiroshi

    2015-06-30

    To assess the isoform specificity of the Ca(2+)/calmodulin-dependent protein kinase kinase (CaMKK)-mediated signaling pathway using a CaMKK inhibitor (STO-609) in living cells, we have established A549 cell lines expressing STO-609-resistant mutants of CaMKK isoforms. Following serial mutagenesis studies, we have succeeded in obtaining an STO-609-resistant CaMKKα mutant (Ala292Thr/Leu233Phe) and a CaMKKβ mutant (Ala328Thr/Val269Phe), which showed sensitivity to STO-609 that was 2-3 orders of magnitude lower without an appreciable effect on kinase activity or CaM requirement. These results are consistent with the results obtained for CaMKK activities in the extracts of A549 cells stably expressing the mutants of CaMKK isoforms. Ionomycin-induced 5'-AMP-activated protein kinase (AMPK) phosphorylation at Thr172 in A549 cells expressing either the wild-type or the STO-609-resistant mutant of CaMKKα was completely suppressed by STO-609 treatment but resistant to the inhibitor in the presence of the CaMKKβ mutant (Ala328Thr/Val269Phe). This result strongly suggested that CaMKKβ is responsible for ionomycin-induced AMPK activation, which supported previous reports. In contrast, ionomycin-induced CaMKIV phosphorylation at Thr196 was resistant to STO-609 treatment in A549 cells expressing STO-609-resistant mutants of both CaMKK isoforms, indicating that both CaMKK isoforms are capable of phosphorylating and activating CaMKIV in living cells. Considering these results together, STO-609-resistant CaMKK mutants developed in this study may be useful for distinguishing CaMKK isoform-mediated signaling pathways in combination with the use of an inhibitor compound.

  7. Evaluation of Nd:YAG laser on partial oxygen saturation of pulpal blood in anterior hypersensitive teeth.

    Science.gov (United States)

    Birang, Reza; Kaviani, Naser; Mohammadpour, Mehdi; Abed, Ahmad Moghareh; Gutknecht, Norbert; Mir, Maziar

    2008-07-01

    Dentine hypersensitivity has of long been known to be a common clinical problem in dental practices. Lasers have recently come to play a prominent role in the treatment of this disorder. They might, however, cause dental pulp damage. This study was conducted to evaluate the effect of Nd:yttrium-aluminum-garnet (YAG) laser on partial oxygen saturation of pulpal blood in sensitive anterior teeth. In this clinical trial, 65 hypersensitive teeth were selected and randomly allocated to two groups. The study group involved Nd:YAG laser treatment, while no treatment was employed for the control group. Using a pulse oximetry system, evaluations were preformed of the partial oxygen saturation in the pulpal blood before, immediately after, 1 week after, and 1 month after the treatment. The results were analyzed using the SPSS software and repeated-measures analysis of variance and paired-samples t tests. The mean partial oxygen saturation of the blood was found to be 85.4% in the study group, which was not significantly different from that of the control group. No significant differences were observed in the control group between the means obtained from pretreatment and post-treatment intervals (P > 0.05). The Post-treatment partial oxygen saturation mean rose to 89.3% (P = 0.001) and remained constant throughout the following week after it. However, no significant differences were found between the pretreatment partial oxygen saturation mean and the same measurement 1 month after treatment (P = 0.702). Nd:YAG laser therapy for dentine desensitization of anterior teeth caused no persistent changes in the partial oxygen saturation of pulpal blood. It may, therefore, be concluded that the diffusion of heat induced by the Nd:YAG laser into the pulp within the limit of the desensitization parameters cause no irreversible damages in the dental pulp.

  8. Oxygen saturation index and severity of hypoxic respiratory failure.

    Science.gov (United States)

    Rawat, Munmun; Chandrasekharan, Praveen K; Williams, Ashley; Gugino, Sylvia; Koenigsknecht, Carmon; Swartz, Daniel; Ma, Chang Xing; Mathew, Bobby; Nair, Jayasree; Lakshminrusimha, Satyan

    2015-01-01

    The oxygenation index (OI = mean airway pressure, MAP × FiO2 × 100 : PaO2) is used to assess the severity of hypoxic respiratory failure (HRF) and persistent pulmonary hypertension of the newborn (PPHN). An indwelling arterial line or arterial punctures are necessary to obtain PaO2 for the calculation of OI. Oxygenation can be continuously and noninvasively assessed using pulse oximetry. The use of the oxygen saturation index (OSI = MAP × FiO2 × 100 : SpO2) can be an alternate method of assessing the severity of HRF. To evaluate the correlation between OSI and OI in the following: (1) neonates with HRF and (2) a lamb model of meconium aspiration syndrome. Human neonates: a retrospective chart review of 74 ventilated late preterm/term neonates with indwelling arterial access and SpO2 values in the first 24 h of life was conducted. OSI and OI were calculated and correlated. Lamb model: arterial blood gases were drawn and preductal SpO2 was documented in 40 term newborn lambs with asphyxia and meconium aspiration. OI and OSI were calculated and correlated with pulmonary vascular resistance (PVR). Mean values of OSI and OI showed a correlation coefficient of 0.952 in neonates (mean value of 308 observations in 74 neonates) and 0.948 in lambs (mean value of 743 observations in 40 lambs). In lambs, with increasing PVR, there was a decrease in OI and OSI. OSI correlates significantly with OI in infants with HRF. This noninvasive measure may be used to assess the severity of HRF and PPHN in neonates without arterial access. © 2015 S. Karger AG, Basel

  9. Prognostic value of cerebral tissue oxygen saturation during neonatal extracorporeal membrane oxygenation.

    Directory of Open Access Journals (Sweden)

    Marie-Philippine Clair

    Full Text Available Extracorporeal membrane oxygenation support is indicated in severe and refractory respiratory or circulatory failures. Neurological complications are typically represented by acute ischemic or hemorrhagic lesions, which induce higher morbidity and mortality. The primary goal of this study was to assess the prognostic value of cerebral tissue oxygen saturation (StcO2 on mortality in neonates and young infants treated with ECMO. A secondary objective was to evaluate the association between StcO2 and the occurrence of cerebral lesions.This was a prospective study in infants < 3 months of age admitted to a pediatric intensive care unit and requiring ECMO support.The assessment of cerebral perfusion was made by continuous StcO2 monitoring using near-infrared spectroscopy (NIRS sensors placed on the two temporo-parietal regions. Neurological lesions were identified by MRI or transfontanellar echography.Thirty-four infants <3 months of age were included in the study over a period of 18 months. The ECMO duration was 10±7 days. The survival rate was 50% (17/34 patients, and the proportion of brain injuries was 20% (7/34 patients. The mean StcO2 during ECMO in the non-survivors was reduced in both hemispheres (p = 0.0008 right, p = 0.03 left compared to the survivors. StcO2 was also reduced in deceased or brain-injured patients compared to the survivors without brain injury (p = 0.002.StcO2 appears to be a strong prognostic factor of survival and of the presence of cerebral lesions in young infants during ECMO.

  10. Growth of the microalgae Neochloris oleoabundans at high partial oxygen pressures and sub-saturating light intensity.

    Science.gov (United States)

    Sousa, Cláudia; de Winter, Lenneke; Janssen, Marcel; Vermuë, Marian H; Wijffels, René H

    2012-01-01

    The effect of partial oxygen pressure on growth of Neochloris oleoabundans was studied at sub-saturating light intensity in a fully-controlled stirred tank photobioreactor. At the three partial oxygen pressures tested (P(O)₂= 0.24; 0.63; 0.84 bar), the specific growth rate was 1.38; 1.36 and 1.06 day(-1), respectively. An increase of the P(CO)₂from 0.007 to 0.02 bar at P(O₂) of 0.84 bar resulted in an increase in the growth rate from 1.06 to 1.36 day(-1). These results confirm that the reduction of algal growth at high oxygen concentrations at sub-saturating light conditions is mainly caused by competitive inhibition of Rubisco. This negative effect on growth can be overcome by restoring the O(2)/CO(2) ratio by an increase in the partial carbon dioxide pressure. In comparison to general practice (P(O(2)) = 0.42 bar), working at partial O(2) pressure of 0.84 bar could reduce the energy requirement for degassing by a factor of 3-4. Copyright © 2011 Elsevier Ltd. All rights reserved.

  11. The effect of sensory stimulation provided by family on arterial blood oxygen saturation in critical care patients.

    Science.gov (United States)

    Yousefi, Hojatollah; Naderi, Mojgan; Daryabeigi, Reza

    2015-01-01

    Stressors in the intensive care unit (ICU) impair patients' comfort, excite the stress response, and increase oxygen consumption in their body. Non-medical interventions are recommended by several studies as a treatment to improve comfort in the ICU patients. Sensory stimulation is one of the most important interventions. Since arterial blood oxygen saturation is an important index of patients' clinical and respiratory condition, this study aimed to investigate the effect of sensory stimulation provided by family on arterial blood oxygen saturation in critical care patients. This study is a clinical trial conducted on 64 patients hospitalized in the ICU wards of Al-Zahra and Kashani hospitals in Isfahan, Iran in 2012 and 2013. The patients were selected by simple sampling method and were randomly assigned to two groups (study and control). Patients' arterial blood oxygen saturations were measured 10 min before, immediately after, 10 min and 30 min after sensory stimulation in the study group, and simultaneously in the control group without any intervention. Repeated measures analysis of variance (ANOVA) showed a significant difference in the mean of arterial blood oxygen saturation levels 10 min before, immediately after, 10 min and 30 min after sensory stimulation in the study group (P 0.18). Application of sensory stimulations as a nursing and non-medical intervention by the family members improves comfort and increases the level of blood oxygen saturation in critical care patients.

  12. Association between minor loading vein architecture and light- and CO2-saturated rates of photosynthetic oxygen evolution among Arabidopsis thaliana ecotypes from different latitudes

    Directory of Open Access Journals (Sweden)

    Christopher M Cohu

    2013-07-01

    Full Text Available Through microscopic analysis of veins and assessment of light- and CO2-saturated rates of photosynthetic oxygen evolution, we investigated the relationship between minor loading vein anatomy and photosynthesis of mature leaves in three ecotypes of Arabidopsis thaliana grown under four different combinations of temperature and photon flux density (PFD. All three ecotypes exhibited greater numbers and cross-sectional area of phloem cells as well as higher photosynthesis rates in response to higher PFD and especially lower temperature. The Swedish ecotype exhibited the strongest response to these conditions, the Italian ecotype the weakest response, and the Col-0 ecotype exhibited an intermediate response. Among all three ecotypes, strong linear relationships were found between light- and CO2-saturated rates of photosynthetic oxygen evolution and the number and area of either sieve elements or of companion and phloem parenchyma cells in foliar minor loading veins, with the Swedish ecotype showing the highest number of cells in minor loading veins (and largest minor veins coupled with unprecedented high rates of photosynthesis. Linear, albeit less significant, relationships were also observed between number and cross-sectional area of tracheids per minor loading vein versus light- and CO2-saturated rates of photosynthetic oxygen evolution. We suggest that sugar distribution infrastructure in the phloem is co-regulated with other features that set the upper limit for photosynthesis. The apparent genetic differences among Arabidopsis ecotypes should allow for future identification of the gene(s involved in augmenting sugar-loading and -transporting phloem cells and maximal rates of photosynthesis.

  13. Oxygen stoichiometry of LaTiO{sub 3} thin films studied by in-situ photoemission

    Energy Technology Data Exchange (ETDEWEB)

    Scheiderer, Philipp; Goessmann, Alex; Sing, Michael; Claessen, Ralph [Universitaet Wuerzburg, Physikalisches Institut and Roentgen Center for Complex Material Systems (RCCM), 97074 Wuerzburg (Germany)

    2015-07-01

    As in the famous oxide heterostructure LaAlO{sub 3}/SrTiO{sub 3} (LAO/STO) a two dimensional electron system is found at the interface between the strongly correlated Mott insulator LaTi{sup 3+}O{sub 3} and the band insulator STO. The stabilization of LaTi{sup 3+}O{sub 3} requires strong reducing growth conditions since the thermodynamically stable bulk phase is the oxygen rich La{sub 2}Ti{sup 4+}{sub 2}O{sub 7}. Therefore, we have systematically studied the impact of the oxygen background atmosphere on LaTi{sup 3+}O{sub 3} thin film growth by PLD. Reflection high-energy diffraction intensity oscillations of the specular spot indicate a layer by layer growth mode for thin films, which merges into the formation of islands for thicker films. In-situ photoemission measurements enables us to determine the oxidation state of Ti indicating excess or lack of oxygen present in the prepared samples. Our experiments show that even for films grown in vacuum, strong oxygen excess is present probably due to oxygen out-diffusion from the STO substrate. We find that an LAO buffer layer serves as an effective barrier for this process. The spectral weight of the lower Hubbard band, being a characteristic feature for the Mott insulating phase, is found to scale inversely with the amount of excess oxygen.

  14. A technique for measuring oxygen saturation in biological tissues based on diffuse optical spectroscopy

    Science.gov (United States)

    Kleshnin, Mikhail; Orlova, Anna; Kirillin, Mikhail; Golubiatnikov, German; Turchin, Ilya

    2017-07-01

    A new approach to optical measuring blood oxygen saturation was developed and implemented. This technique is based on an original three-stage algorithm for reconstructing the relative concentration of biological chromophores (hemoglobin, water, lipids) from the measured spectra of diffusely scattered light at different distances from the probing radiation source. The numerical experiments and approbation of the proposed technique on a biological phantom have shown the high reconstruction accuracy and the possibility of correct calculation of hemoglobin oxygenation in the presence of additive noise and calibration errors. The obtained results of animal studies have agreed with the previously published results of other research groups and demonstrated the possibility to apply the developed technique to monitor oxygen saturation in tumor tissue.

  15. COMPARISON OF THE EFFECTIVENESS OF TWO LEVELS OF SUCTION PRESSURE ON OXYGEN SATURATION IN PATIENTS WITH ENDOTRACHEAL TUBE

    Directory of Open Access Journals (Sweden)

    Muhaji

    2017-12-01

    Full Text Available Background: Endotracheal suctioning is one of the common supportive measures in intensive care units (ICU, which may be related to complications such as hypoxia. However, a questionable efficacy is still identified to choose suctioning pressure between 130 mmHg and 140 mmHg that is effective for patients with endotracheal tube. Objective: To compare the effectiveness of 130 mmHg and 140 mmHg suctioning pressure on oxygen saturation in patients with endotracheal tube. Methods: This research used a quasy experimental design with pretest and posttest group. The study was conducted from 31 January to 1 March 2017 in the Hospital of Panti Wilasa Citarum and Hospital of Roemani Muhammadiyah Semarang. There were 30 samples recruited using consecutive sampling, with 15 assigned in the 130 mmHg and 140 mmHg suctioning pressure group. Pulse oximetry was used to measure oxygen saturation. Paired t-test and Independent t-test were used for data analysis. Results: Findings showed that there was a statistically significant effect of 130 and 140 mmHg suctioning pressure on oxygen saturation in patients with ETT with p-value <0.05. There was a significant mean difference of oxygen saturation between 130 mmHg and 140 mmHg suctioning pressure group with p-value 0.004 (<0.05. The mean difference of oxygen saturation between both groups was 13.157. Conclusion: The 140 mmHg suctioning pressure is more effective compared with 130 mmHg suctioning pressure in increasing oxygen saturation in patients with ETT.

  16. [Association between oxygen saturation and cognitive function in older adults from longevity areas in China].

    Science.gov (United States)

    Su, L Q; Yin, Z X; Xu, N; Lyu, Y B; Luo, J S; Shi, X M

    2016-07-06

    To explore the relationship between oxygen saturation (SpO2) and cognitive function in older adults from longevity areas in China. A total of 2 285 participants aged ≥65 years according to the 2012 Chinese Longitudinal Healthy Longevity Survey were included in this study. Among them, 1 739 participants aged 65-99 years were randomly selected, and 546 participants aged ≥100 years were totally involved. A standardized questionaire was used to collect the information of demographic characteristics, life styles, disease history, etc. Cognitive function was evaluated using the Mini Mental State Examination Scale. Arterial oxygen saturation and heart rate were measured by pulse oximetry. Differences in cognitive function between the low SpO2 group (cognitive function. The total score of cognitive function was 22.6±9.7 for the 1 922 participants in the normal SpO2 group, and 18.8 ± 11.0 for the 363 participants in the low SpO2 group (t=6.11, Pcognitive impairment in the low SpO2 group was 36.6% (n=133), and 22.9% (n=441) in the normal SpO2 group (χ(2)=30.44, Pcognitive impairment increased with each year of increased age (OR 1.07; (95% CI: 1.05-1.09), Pcognitive impairment (OR 1.64; (95% CI: 1.11-2.43), OR 1.73; (95% CI: 1.27-2.35), OR 3.54; (95% CI: 2.62-4.79), OR 1.38; (95% CI: 1.02-1.86), OR 2.05; (95% CI: 1.34-3.13), OR 1.83; (95% CI: 1.13-2.97), respectively, Page group showed that the association between SpO2 and cognitive impairment was most significant in participants aged ≥90 years (OR 1.58; (95% CI: 1.09-2.28), P=0.016). Low oxygen saturation was associated with higher risk of cognitive impairment in our population of elderly adults.

  17. Morphodynamic Modeling Using The SToRM Computational System

    Science.gov (United States)

    Simoes, F.

    2016-12-01

    The framework of the work presented here is the open source SToRM (System for Transport and River Modeling) eco-hydraulics modeling system, which is one of the models released with the iRIC hydraulic modeling graphical software package (http://i-ric.org/). SToRM has been applied to the simulation of various complex environmental problems, including natural waterways, steep channels with regime transition, and rapidly varying flood flows with wetting and drying fronts. In its previous version, however, channel bed was treated as static and the ability of simulating sediment transport rates or bed deformation was not included. The work presented here reports SToRM's newly developed extensions to expand the system's capability to calculate morphological changes in alluvial river systems. The sediment transport module of SToRM has been developed based on the general recognition that meaningful advances depend on physically solid formulations and robust and accurate numerical solution methods. The basic concepts of mass and momentum conservation are used, where the feedback mechanisms between the flow of water, the sediment in transport, and the bed changes are directly incorporated in the governing equations used in the mathematical model. This is accomplished via a non-capacity transport formulation based on the work of Cao et al. [Z. Cao et al., "Non-capacity or capacity model for fluvial sediment transport," Water Management, 165(WM4):193-211, 2012], where the governing equations are augmented with source/sink terms due to water-sediment interaction. The same unsteady, shock-capturing numerical schemes originally used in SToRM were adapted to the new physics, using a control volume formulation over unstructured computational grids. The presentation will include a brief overview of these methodologies, and the result of applications of the model to a number of relevant physical test cases with movable bed, where computational results are compared to experimental data.

  18. White Matter Damage Relates to Oxygen Saturation in Children With Sickle Cell Anemia Without Silent Cerebral Infarcts.

    Science.gov (United States)

    Kawadler, Jamie M; Kirkham, Fenella J; Clayden, Jonathan D; Hollocks, Matthew J; Seymour, Emma L; Edey, Rosanna; Telfer, Paul; Robins, Andrew; Wilkey, Olu; Barker, Simon; Cox, Tim C S; Clark, Chris A

    2015-07-01

    Sickle cell anemia is associated with compromised oxygen-carrying capability of hemoglobin and a high incidence of overt and silent stroke. However, in children with no evidence of cerebral infarction, there are changes in brain morphometry relative to healthy controls, which may be related to chronic anemia and oxygen desaturation. A whole-brain tract-based spatial statistics analysis was carried out in 25 children with sickle cell anemia with no evidence of abnormality on T2-weighted magnetic resonance imaging (13 male, age range: 8-18 years) and 14 age- and race-matched controls (7 male, age range: 10-19 years) to determine the extent of white matter injury. The hypotheses that white matter damage is related to daytime peripheral oxygen saturation and steady-state hemoglobin were tested. Fractional anisotropy was found to be significantly lower in patients in the subcortical white matter (corticospinal tract and cerebellum), whereas mean diffusivity and radial diffusivity were higher in patients in widespread areas. There was a significant negative relationship between radial diffusivity and oxygen saturation (Plevel negative relationship between radial diffusivity and hemoglobin (Pcell anemia, and provides for the first time direct evidence of a relationship between brain microstructure and markers of disease severity (eg, peripheral oxygen saturation and steady-state hemoglobin). This study suggests that diffusion tensor imaging metrics may serve as a biomarker for future trials of reducing hypoxic exposure. © 2015 American Heart Association, Inc.

  19. [Sedation with intravenous midazolam during upper gastrointestinal endoscopy--changes in hemodynamics, oxygen saturation and memory].

    Science.gov (United States)

    Mizuno, Ju; Matsuki, Michiko; Gouda, Yoshinori; Nishiyama, Tomoki; Hanaoka, Kazuo

    2003-09-01

    Cardiorespiratory adverse effects are often observed in patients undergoing upper gastrointestinal endoscopy with sedation. In this study, we examined hemodynamics, oxygen saturation and memory during upper gastrointestinal endoscopy under sedation with intravenous midazolam. Eight healthy outpatients without any obvious complications received intravenous midazolam 5 mg for sedation for upper gastrointestinal endoscopy. Blood pressure, heart rate and percutaneous arterial oxygen saturation (SpO2) were measured before, during and after endoscopy. After the arousal by intravenous flumazenil, we inquired the patients about the level of memory during the endoscopy. Blood pressure decreased significantly two minutes after midazolam administration, but increased significantly after the insertion of an endoscope which was not different from the control value. Heart rate increased significantly one and three minutes after the insertion of the endoscope. SpO2 decreased significantly after midazolam administration and stayed at around 95%. No patients remembered the procedure. Sedation with intravenous midazolam during upper gastrointestinal endoscopy is useful to control the cardiovascular responses, and to obtain amnesia. However, a decrease in SpO2 should be watched carefully.

  20. Retinopathy of prematurity and induced changes in arterial oxygen saturation with near infrared spectrophotometry: a retrospective cohort study

    Science.gov (United States)

    von Siebenthal, K.; Keel, M.; Dietz, V.; Fauchere, J. C.; Martin, X.; Wolf, Martin; Duc, G.; Bucher, H. U.

    1996-10-01

    Near-infrared spectrophotometry (NIRS) is a noninvasive method for measuring oxygenated and deoxygenated hemoglobin in the neonatal brain. Using oxygen as a tracer, it is possible to calculate cerebral blood flow (cbf) and hemoglobin concentration (cHbc), which corresponds to cerebral blood volume, by inducing small changes in arterial oxygen saturation. Variability of tcpO2 is considered to be associated with severe retinopathy of prematurity (ROP). A preliminary analysis without control found a 51 percent incidence of ROP in infants subjected to NIRS measurements whereas among infants who were not exposed to oxygen changes, only 29 percent developed ROP. A controlled study with matched pairs was performed. Thirty-nine premature newborns who had received NIRS recordings were matched with 39 out of 172 infants who had not received NIRS. Using this controlled study design there was no difference in the incidence and severity of ROP between the two groups. The conclusions are that: 1) small changes in oxygen saturation of 3 to 10 percent to measure cbf and cHbc did not increase the incidence or the degree of severity of ROP. 2) A controlled study design is important. Analyses of uncontrolled data would have led to the conclusion that oxygen changes as used with NIRS increase the risk of ROP.

  1. Scavenging of oxygen vacancies at modulation-doped oxide interfaces: Evidence from oxygen isotope tracing

    DEFF Research Database (Denmark)

    Chen, Yunzhong; Döbeli, M.; Pomjakushina, E.

    2017-01-01

    , the mechanisms underlying the extreme mobility enhancement remain elusive. Herein, we used 18O isotope exchanged SrTi18O3 as substrates to create 2DEG at room temperature with and without the LSMO buffer layer. By mapping the oxygen profile across the interface between STO18 and disordered LaAlO3 or yttria...

  2. Investigating tissue respiration and skin microhaemocirculation under adaptive changes and the synchronization of blood flow and oxygen saturation rhythms

    International Nuclear Information System (INIS)

    Dunaev, A V; Palmer, S G; Stewart, N A; Sokolovski, S G; Rafailov, E U; Sidorov, V V; Krupatkin, A I; Rafailov, I E

    2014-01-01

    Multi-functional laser non-invasive diagnostic systems allow the study of a number of microcirculatory parameters, including index of blood microcirculation (I m ) (by laser Doppler flowmetry, LDF) and oxygen saturation (S t O 2 ) of skin tissue (by tissue reflectance oximetry, TRO). This research aimed to use such a system to investigate the synchronization of microvascular blood flow and oxygen saturation rhythms under normal and adaptive change conditions. Studies were conducted on eight healthy volunteers of 21–49 years. These volunteers were observed between one and six months, totalling 422 basic tests (3 min each). Measurements were performed on the palmar surface of the right middle finger and the lower forearm's medial surface. Rhythmic oscillations of LDF and TRO were studied using wavelet analysis. Combined tissue oxygen consumption data for all volunteers during ‘adaptive changes’ increased relative to normal conditions with and without arteriovenous anastomoses. Data analysis revealed resonance and synchronized rhythms in microvascular blood flow and oxygen saturation as an adaptive change in myogenic oscillation (vasomotion) resulting from exercise and possibly psychoemotional stress. Synchronization of myogenic rhythms during adaptive changes may lead to increased oxygen consumption as a result of increased microvascular blood flow velocity. (paper)

  3. Tissue oximetry: a comparison of mean values of regional tissue saturation, reproducibility and dynamic range of four NIRS-instruments on the human forearm

    DEFF Research Database (Denmark)

    Hyttel-Sørensen, Simon; Sorensen, Line C; Riera, Joan

    2011-01-01

    We compared absolute values of regional tissue hemoglobin saturation (StO(2)), reproducibility, and dynamic range of four different instruments on the forearm of adults. The sensors were repositioned 10 times on each subject. Dynamic range was estimated by exercise with subsequent arterial occlus...

  4. Association between intraoperative tissue oxygenation, arterial blood pressure and noradrenaline use in urological patients

    NARCIS (Netherlands)

    Spruit, R.J.; Schwarte, L.A.; Hakenberg, O.W.; Scheeren, T.

    2011-01-01

    Background and Goal of Study: Inadequate tissue oxygenation should be prevented during surgery as it might cause postoperative morbidity. In this observational study we looked at factors that might influence tissue oxygenation (StO2) such as blood pressure and use of vasoactive drugs. Materials and

  5. Utjecaj liberalizacije na tržište stočarskih proizvoda

    Directory of Open Access Journals (Sweden)

    Ružica Lončarić

    2004-01-01

    Full Text Available Ulaskom u Svjetsku trgovinsku organizaciju Republika Hrvatska je dokazala spremnost za izazove liberalizacije i globalizacije svjetskoga tržišta. Ovom je koraku prethodilo i potpisivanju drugih značajnih dokumenata za uključenje u europski integracijski proces, kao što je Pakt o stabilizaciji u istočnoj Europi, Sporazum o stabilizaciji i Pridruživanju EU i RH, službeno priključenje CEFTA-i, te službena prijava za članstvo u EU, koji na provođenje određenih reformi i prilagodbu u političkome, gospodarskom i pravnom smislu. Kako se hrvatska poljoprivreda, pogotovo grana stočarstva, od osamostaljenja i prihvaćanja tržišnog sustava gospodarenja, nalazi u velikoj krizi, u radu se analizira položaj stočarstva s obzirom na uvjete proizvodnje i brojno stanje stoke, tržište stočarskih proizvoda uz pomoć dinamičke raščlambe sustava proizvodnje stočarskih proizvoda, te se daju prognoze na koji će se način odvijati adaptacija stočarstva u uvjetima EU s obzirom na konkurentnost naših stočarskih proizvoda u europskom okruženju tes obzirom na liberalizacijske obveze. Rezultati analizirani u radu pokazuju kako je hrvatska proizvodnja i tržište stočarskih proizvoda u dubokoj krizi, te da bi bilo potrebno poduzeti niz tržišno-cjenovnih mjera agrarne politike koje bi uredilo navedeno tržište s obzirom na obveze i pravila o liberalizaciji trgovine unutar europskog tržišta.

  6. Oxygen-doped Sb{sub 4}Te phase change films for high-temperature data retention and low-power application

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Yifeng [Functional Materials Research Laboratory, Tongji University, Shanghai 200092 (China); School of Mathematics and Physics, Jiangsu Teachers University of Technology, Changzhou 213001 (China); Sun, Mingcheng [Functional Materials Research Laboratory, Tongji University, Shanghai 200092 (China); Song, Sannian; Song, Zhitang [State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Micro-System and Information Technology, Chinese Academy of Sciences, Shanghai 200050 (China); Zhai, Jiwei, E-mail: apzhai@tongji.edu.cn [Functional Materials Research Laboratory, Tongji University, Shanghai 200092 (China)

    2013-02-25

    Highlights: Black-Right-Pointing-Pointer O-doped Sb{sub 4}Te phase-change films were reported. Black-Right-Pointing-Pointer The amorphous-to-crystalline transitions of O-doped Sb{sub 4}Te films were studied. Black-Right-Pointing-Pointer By doping oxygen, the stability of Sb{sub 4}Te films is improved greatly. Black-Right-Pointing-Pointer The resistance of the Sb{sub 4}Te films increases by doping oxygen. - Abstract: The amorphous-to-crystalline transitions of oxygen-doped Sb{sub 4}Te (STO) films are investigated by in situ film resistance measurements. The crystalline temperature and resistance of the oxygen-doped films increase. The analysis of X-ray diffractomer (XRD) and X-ray photoelectron spectroscopy (XPS) indicate that the films with doping of a small amount of oxygen atoms can refine the grain size and form oxide, improving the resistance and thermal stability of phase change films. Excessive oxygen in Sb{sub 4}Te will make Te separate, resulting in deteriorating the stability. As a result, STO2 film has the relatively high activation energy for crystallization. The 10-year lifetime is raised from 29 Degree-Sign C of undoped Sb{sub 4}Te film to 102 Degree-Sign C of STO3 film. Phase transition from amorphous state to crystalline state is observed at relatively lower power, compared with a device using Ge{sub 2}Sb{sub 2}Te{sub 5} film.

  7. Comparison of emissions and performance between saturated cyclic oxygenates and aromatics in a heavy-duty diesel engine

    NARCIS (Netherlands)

    Zhou, L.; Boot, M.D.; Johansson, B.H.

    2013-01-01

    Emissions and fuel economy are evaluated for two types of biofuels, namely 2-phenyl ethanol and cyclohexaneethanol. Both are derived from lignin, a form of lignocellulosic biomass. The former and latter oxygenates have an aromatic and aliphatic (i.e. saturated) ring structure, respectively. Two

  8. Diffuse optical characterization of an exercising patient group with peripheral artery disease

    Science.gov (United States)

    Putt, Mary; Chandra, Malavika; Yu, Guoqiang; Xing, Xiaoman; Han, Sung Wan; Lech, Gwen; Shang, Yu; Durduran, Turgut; Zhou, Chao; Yodh, Arjun G.; Mohler, Emile R.

    2013-01-01

    Abstract. Peripheral artery disease (PAD) is a common condition with high morbidity. While measurement of tissue oxygen saturation (StO2) has been demonstrated, this is the first study to assess both StO2 and relative blood flow (rBF) in the extremities of PAD patients. Diffuse optics is employed to measure hemodynamic response to treadmill and pedal exercises in 31 healthy controls and 26 patients. For StO2, mild and moderate/severe PAD groups show pronounced differences compared with controls. Pre-exercise mean StO2 is lower in PAD groups by 9.3% to 10.6% compared with means of 63.5% to 66.2% in controls. For pedal, relative rate of return of StO2 to baseline is more rapid in controls (p<0.05). Patterns of rBF also differ among groups. After both exercises, rBF tend to occur at depressed levels among severe PAD patients compared with healthy (p<0.05); post-treadmill, rBF tend to occur at elevated levels among healthy compared with severe PAD patients (p<0.05). Additionally, relative rate of return to baseline StO2 is more rapid among subjects with reduced levels of depression in rBF (p=0.041), even after adjustment for ankle brachial index. This suggests a physiologic connection between rBF and oxygenation that can be measured using diffuse optics, and potentially employed as an evaluative tool in further studies. PMID:23708193

  9. Lack of differences in the regional variation of oxygen saturation in larger retinal vessels in diabetic maculopathy and proliferative diabetic retinopathy.

    Science.gov (United States)

    Jørgensen, Christina Mørup; Bek, Toke

    2017-06-01

    Diabetic retinopathy is characterised by morphological lesions in the ocular fundus related to disturbances in retinal blood flow. The two vision threatening forms of retinopathy show specific patterns of distribution of retinal lesions with proliferative diabetic retinopathy (PDR) developing secondary to ischaemia and hypoxia in the retinal periphery and diabetic maculopathy (DM) developing secondary to hyperperfusion and increased vascular permeability in the macular area. These differences in the distribution of retinal lesions might be reflected in regional differences in oxygen saturation in the larger retinal vessels. Dual-wavelength retinal oximetry was performed in 30 normal persons, 30 patients with DM and 30 patients with PDR, and the oxygen saturation was measured in peripapillary vessels supplying the four retinal quadrants and in branches from the upper temporal arcades supplying, respectively, the macular area and the retinal periphery. The overall oxygen saturation was significantly higher in diabetic patients than in normal persons and the arteriovenous (AV) saturation difference significantly lower in the patients with DM. The regional variation in oxygen saturation was similar in the three studied groups with a decreasing saturation from the upper nasal through the lower nasal, lower temporal and the upper temporal peripapillary vessels, and with a significantly higher oxygen saturation in venules draining the macular area than in venules draining the retinal periphery. The regional differences in retinal lesions in vision threatening diabetic retinopathy are not reflected in regional differences in the oxygen saturation of larger retinal vessels. The development of vision threatening diabetic retinopathy depends on other factors, such as, for example, regional differences in the retinal microcirculation. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

  10. Design and commissioning of ReStoX for XENON1T

    Energy Technology Data Exchange (ETDEWEB)

    Scheibelhut, Melanie [Institut fuer Physik, Johannes Gutenberg Universitaet Mainz (Germany)

    2015-07-01

    The XENON1T experiment, currently under construction at the Gran Sasso underground laboratory LNGS, uses the concept of a xenon dual-phase (liquid/gas) time projection chamber to search for Dark Matter particles. This requires cooling to about 175 K and liquefaction of the noble gas. The ReStoX (Recovery and Storage of Xenon) is a novel device to store and recover up to 7 tons of xenon - either in liquid phase at cryogenic temperatures and 1-2 bar of pressure, or in gaseous form at room temperature at about 70 bar of pressure. The ReStoX system consists of a double insulated stainless steel sphere with liquid nitrogen cooling loops distributed across the inner sphere. A condenser on the inside, also operated with liquid nitrogen, provides a cooling power of 3 kW. ReStoX is designed to provide an effective means for various operating modes: to fill the TPC fast, to recover xenon from the TPC under normal and emergency conditions, to store xenon safely in liquid or gaseous form, or to remain in cold standby nearly empty as a safety device. Here we present the design and first commissioning results.

  11. Need. for Sto.ndo.rdizo.tion

    African Journals Online (AJOL)

    1969-05-13

    Need. for Sto.ndo.rdizo.tion. Speech delivered at a dinner given by the Ethiopian Association of Engineers and. Architects on May 13, 1969. By Lars Wallden, UN adviser on standardization, Ministry of Commerce, Industry & Tourism and. Gebre Kiros Habtu, mechanical engineer, Ministry of Commerce, Industry & Tourism.

  12. The Effects of Massage with Coconut and Sunflower Oils on Oxygen Saturation of Premature Infants with Respiratory Distress Syndrome Treated With Nasal Continuous Positive Airway Pressure

    Directory of Open Access Journals (Sweden)

    Sousan Valizadeh

    2012-11-01

    Full Text Available Introduction: Nowadays particular emphasis is placed on the developmental aspects of premature infants care. Massage therapy is one of the best-known methods of caring. Due to the minimal touch policy in neonatal intensive care units (NICUs, massaging is not usually performed on premature infants. However, there is not sufficient evidence to support the claim that newborn infants with complex medical conditions should not be massaged. This study aimed to determine the effects of massage with coconut and sunflower oils on oxygen saturation of infants with respiratory distress syndrome (RDS treated with nasal continuous positive airway pressure (NCPAP. Methods: This was a randomized controlled trial on 90 newborns who were admitted to Alzahra Hospital (Tabriz, Iran. The infants were divided into control and massage therapy groups (massage with coconut and sunflower oils. Data was collected using a hospital documentation form. A 15-minute daily massage was performed for 3 days. Respiratory rate (RR, fraction of inspired oxygen (FiO2 and oxygen saturation were measured 5 minutes before the massage, 3 times during the massage, and 5 minutes after the massage. The collected data was analyzed using a mixed model. Results: In comparison to coconut oil and control groups, mean oxygen saturation of sunflower oil group was improved. In addition, the coconut massage group showed lower oxygen saturation than the control group but was all values were within the normal range. Although massage decreased oxygen saturation, there was no need to increase FiO2. Conclusion: Massage therapy can provide developmental care for infants treated with NCPAP.

  13. Nitric oxide formation from the reaction of nitrite with carp and rabbit hemoglobin at intermediate oxygen saturations

    DEFF Research Database (Denmark)

    Jensen, Frank Bo

    2008-01-01

    The nitrite reductase activity of deoxyhemoglobin has received much recent interest because the nitric oxide produced in this reaction may participate in blood flow regulation during hypoxia. The present study used spectral deconvolution to characterize the reaction of nitrite with carp and rabbit...... hemoglobin at different constant oxygen tensions that generate the full range of physiological relevant oxygen saturations. Carp is a hypoxia-tolerant species with very high hemoglobin oxygen affinity, and the high R-state character and low redox potential of the hemoglobin is hypothesized to promote...... NO generation from nitrite. The reaction of nitrite with deoxyhemoglobin leads to a 1 : 1 formation of nitrosylhemoglobin and methemoglobin in both species. At intermediate oxygen saturations, the reaction with deoxyhemoglobin is clearly favored over that with oxyhemoglobin, and the oxyhemoglobin reaction...

  14. Towards the integration of StoRM on Amazon Simple Storage Service (S3)

    Energy Technology Data Exchange (ETDEWEB)

    Andreozzi, S; Magnoni, L; Zappi, R [INFN-CNAF, Viale Carlo Berti Pichat, 6/2, 40127, Bologna (Italy)], E-mail: sergio.andreozzi@cnaf.infn.it, E-mail: luca.magnoni@cnaf.infn.it, E-mail: riccardo.zappi@cnaf.infn.it

    2008-07-15

    In Grid systems, a core resource being shared among geographically-dispersed communities of users is the storage. For this resource, a standard interface specification (Storage Resource Management or SRM) was defined and is being evolved in the context of the Open Grid Forum. By implementing this interface, all storage resources part of a Grid could be managed in an homogenous fashion. In this work, we consider the extension of StoRM (STOrage Resource Manager, an implementation of SRM v2.2) in order to integrate a new type of storage resource: the Amazon Simple Storage Service (Amazon S3). Amazon S3 is a simple Web services interface offering access to the same highly scalable, reliable, fast, inexpensive data storage infrastructure that Amazon uses to run its own global network of Web sites. By performing this integration, we offer to the Grid community the capability to manage and access an incredible amount of storage resources freeing them from considering the costs associated with server maintenance, or whether they have enough storage available. The characteristics of StoRM are suitable for a smooth integration with Amazon S3. In particular, StoRM is designed to be easily adapted to the underlying storage resource via a plug-in mechanism, therefore a new plugin for integration with the Amazon S3 Web Service will be written. As regards the access policies, StoRM translates the Grid authorization rules into the Amazon S3 ones and applies them to the Amazon Web Services identity.

  15. Towards the integration of StoRM on Amazon Simple Storage Service (S3)

    International Nuclear Information System (INIS)

    Andreozzi, S; Magnoni, L; Zappi, R

    2008-01-01

    In Grid systems, a core resource being shared among geographically-dispersed communities of users is the storage. For this resource, a standard interface specification (Storage Resource Management or SRM) was defined and is being evolved in the context of the Open Grid Forum. By implementing this interface, all storage resources part of a Grid could be managed in an homogenous fashion. In this work, we consider the extension of StoRM (STOrage Resource Manager, an implementation of SRM v2.2) in order to integrate a new type of storage resource: the Amazon Simple Storage Service (Amazon S3). Amazon S3 is a simple Web services interface offering access to the same highly scalable, reliable, fast, inexpensive data storage infrastructure that Amazon uses to run its own global network of Web sites. By performing this integration, we offer to the Grid community the capability to manage and access an incredible amount of storage resources freeing them from considering the costs associated with server maintenance, or whether they have enough storage available. The characteristics of StoRM are suitable for a smooth integration with Amazon S3. In particular, StoRM is designed to be easily adapted to the underlying storage resource via a plug-in mechanism, therefore a new plugin for integration with the Amazon S3 Web Service will be written. As regards the access policies, StoRM translates the Grid authorization rules into the Amazon S3 ones and applies them to the Amazon Web Services identity

  16. Design of a visible-light spectroscopy clinical tissue oximeter.

    Science.gov (United States)

    Benaron, David A; Parachikov, Ilian H; Cheong, Wai-Fung; Friedland, Shai; Rubinsky, Boris E; Otten, David M; Liu, Frank W H; Levinson, Carl J; Murphy, Aileen L; Price, John W; Talmi, Yair; Weersing, James P; Duckworth, Joshua L; Hörchner, Uwe B; Kermit, Eben L

    2005-01-01

    We develop a clinical visible-light spectroscopy (VLS) tissue oximeter. Unlike currently approved near-infrared spectroscopy (NIRS) or pulse oximetry (SpO2%), VLS relies on locally absorbed, shallow-penetrating visible light (475 to 625 nm) for the monitoring of microvascular hemoglobin oxygen saturation (StO2%), allowing incorporation into therapeutic catheters and probes. A range of probes is developed, including noncontact wands, invasive catheters, and penetrating needles with injection ports. Data are collected from: 1. probes, standards, and reference solutions to optimize each component; 2. ex vivo hemoglobin solutions analyzed for StO2% and pO2 during deoxygenation; and 3. human subject skin and mucosal tissue surfaces. Results show that differential VLS allows extraction of features and minimization of scattering effects, in vitro VLS oximetry reproduces the expected sigmoid hemoglobin binding curve, and in vivo VLS spectroscopy of human tissue allows for real-time monitoring (e.g., gastrointestinal mucosal saturation 69+/-4%, n=804; gastrointestinal tumor saturation 45+/-23%, n=14; and p<0.0001), with reproducible values and small standard deviations (SDs) in normal tissues. FDA approved VLS systems began shipping earlier this year. We conclude that VLS is suitable for the real-time collection of spectroscopic and oximetric data from human tissues, and that a VLS oximeter has application to the monitoring of localized subsurface hemoglobin oxygen saturation in the microvascular tissue spaces of human subjects.

  17. Photoirradiation system with depth optical dosimetry control in initial oxygen saturation measurement

    International Nuclear Information System (INIS)

    Quintanar, L.; Stolik, S.; Rosa, J. de la; Moreno, E.

    2012-01-01

    Photodynamic Therapy is a technique in which a photosensitizing substance is applied that is activated by light and it generates reactive oxygen species which cause selective cell destruction. The efficiency of the therapy is affected by the parameters dose. In this work it is shown a photo-irradiation system for superficial Photodynamic Therapy, using as a light source a light emitting diode with an automatic control of optical power based on a model of the distribution of light in depth that was tested in tissue phantoms. It also has a reflective pulse oximeter for the measurement of the initial oxygen saturation. (Author)

  18. Detection of cerebral arterial gas embolism using regional cerebral oxygen saturation, quantitative electroencephalography, and brain oxygen tension in the swine

    NARCIS (Netherlands)

    Weenink, R. P.; Hollmann, M. W.; Stevens, M. F.; Kager, J.; van Gulik, T. M.; van Hulst, R. A.

    2014-01-01

    Cerebral air emboli occur as a complication of invasive medical procedures. The sensitivity of cerebral monitoring methods for the detection of air emboli is not known. This study investigates the utility of electroencephalography and non-invasively measured cerebral oxygen saturation in the

  19. Non-invasive evaluation of blood oxygen saturation and hematocrit from T1 and T2 relaxation times: In-vitro validation in fetal blood.

    Science.gov (United States)

    Portnoy, Sharon; Seed, Mike; Sled, John G; Macgowan, Christopher K

    2017-12-01

    We propose an analytical method for calculating blood hematocrit (Hct) and oxygen saturation (sO 2 ) from measurements of its T 1 and T 2 relaxation times. Through algebraic substitution, established two-compartment relationships describing R1=T1-1 and R2=T2-1 as a function of hematocrit and oxygen saturation were rearranged to solve for Hct and sO 2 in terms of R 1 and R 2 . Resulting solutions for Hct and sO 2 are the roots of cubic polynomials. Feasibility of the method was established by comparison of Hct and sO 2 estimates obtained from relaxometry measurements (at 1.5 Tesla) in cord blood specimens to ground-truth values obtained by blood gas analysis. Monte Carlo simulations were also conducted to assess the effect of T 1 , T 2 measurement uncertainty on precision of Hct and sO 2 estimates. Good agreement was observed between estimated and ground-truth blood properties (bias = 0.01; 95% limits of agreement = ±0.13 for Hct and sO 2 ). Considering the combined effects of biological variability and random measurement noise, we estimate a typical uncertainty of ±0.1 for Hct, sO 2 estimates. Results demonstrate accurate quantification of Hct and sO 2 from T 1 and T 2 . This method is applicable to noninvasive fetal vessel oximetry-an application where existing oximetry devices are unusable or require risky blood-sampling procedures. Magn Reson Med 78:2352-2359, 2017. © 2017 International Society for Magnetic Resonance in Medicine. © 2017 International Society for Magnetic Resonance in Medicine.

  20. Study of Al-Si Alloy Oxygen Saturation on Its Microstructure and Mechanical Properties

    Directory of Open Access Journals (Sweden)

    Arkady Finkelstein

    2017-07-01

    Full Text Available One of the main goals of modern materials research is obtaining different microstructures and studying their influence on the mechanical properties of metals; aluminum alloys are particularly of interest due to their advanced performance. Traditionally, their required properties are obtained by alloying process, modification, or physical influence during solidification. The present work describes a saturation of the overheated AlSi7Fe1 casting alloy by oxides using oxygen blowing approach in overheated alloy. Changes in metals’ microstructural and mechanical properties are also described in the work. An Al10SiFe intermetallic complex compound was obtained as a preferable component to Al2O3 precipitation on it, and its morphology was investigated by scanning electron microscopy. The mechanical properties of the alloy after the oxygen blowing treatment are discussed in this work.

  1. Children’s Oxygen Administration Strategies Trial (COAST:  A randomised controlled trial of high flow versus oxygen versus control in African children with severe pneumonia [version 2; referees: 2 approved

    Directory of Open Access Journals (Sweden)

    Kathryn Maitland

    2018-01-01

    Full Text Available Background: In Africa, the clinical syndrome of pneumonia remains the leading cause of morbidity and mortality in children in the post-neonatal period. This represents a significant burden on in-patient services. The targeted use of oxygen and simple, non-invasive methods of respiratory support may be a highly cost-effective means of improving outcome, but the optimal oxygen saturation threshold that results in benefit and the best strategy for delivery are yet to be tested in adequately powered randomised controlled trials. There is, however, an accumulating literature about the harms of oxygen therapy across a range of acute and emergency situations that have stimulated a number of trials investigating permissive hypoxia. Methods: In 4200 African children, aged 2 months to 12 years, presenting to 5 hospitals in East Africa with respiratory distress and hypoxia (oxygen saturation or = 80% (permissive hypoxia; and High flow using AIrVO2TM compared with low flow delivery (routine care. Discussion: The overarching objective is to address the key research gaps in the therapeutic use of oxygen in resource-limited setting in order to provide a better evidence base for future management guidelines. The trial has been designed to address the poor outcomes of children in sub-Saharan Africa, which are associated with high rates of in-hospital mortality, 9-10% (for those with oxygen saturations of 80-92% and 26-30% case fatality for those with oxygen saturations <80%. Clinical trial registration: ISRCTN15622505 Trial status: Recruiting

  2. The relationship between cerebral oxygen saturation changes and post operative neurologic complications in patients undergoing cardiac surgery

    International Nuclear Information System (INIS)

    Negargar, S.; Mahmoudpour, A.; Taheri, R.; Sarvin, S.

    2007-01-01

    To study the relationship between cerebral oxygen saturation changes and postoperative neurologic complications. Seventy two adult patients with ASA class II, III who were scheduled for elective cardiac surgery, were randomized into three groups: Group I: with CPB (on -pump) Group II: without CPB (off- pump) Group III: valve surgery. Neuropsychological outcome was assessed by the Mini-Mental State Examination (MMSE). Cerebral oxygen saturation was also measured. There was no statistical difference in desaturation of more than 20% among three groups (P=0.113) but it was significant between group I and II (P=0.042). Changes of rSo/sub 2/ in different hours of surgery was significant in group I and group II (P=0.0001 in both) but it was not significant in group III ( P=0.075) . Although cerebral oximetry is a noninvasive and useful method of monitoring during cardiac surgery, it has low accuracy to determine postoperative neurologic complications. (author)

  3. Mental abilities and performance efficacy under a simulated 480 meters helium-oxygen saturation diving

    Directory of Open Access Journals (Sweden)

    gonglin ehou

    2015-07-01

    Full Text Available Stress in extreme environment severely disrupts human physiology and mental abilities. The present study investigated the cognition and performance efficacy of four divers during a simulated 480 meters helium-oxygen saturation diving. We analyzed the spatial memory, 2D/3D mental rotation functioning, grip strength, and hand-eye coordination ability in four divers during the 0 – 480 meters compression and decompression processes of the simulated diving. The results showed that except for its mild decrease on grip strength, the high atmosphere pressure condition significantly impaired the hand-eye coordination (especially at 300 meters, the reaction time and correct rate of mental rotation, as well as the spatial memory (especially as 410 meters, showing high individual variability. We conclude that the human cognition and performance efficacy are significantly affected during deep water saturation diving.

  4. Changes in retinal oxygen saturation after intravitreal aflibercept in patients with diabetic macular edema

    DEFF Research Database (Denmark)

    Blindbæk, Søren Leer; Peto, Tunde; Grauslund, Jakob

    2017-01-01

    Design of study: Three months prospective interventional study. Purpose: To evaluate changes in retinal arterial and venous oxygen saturation after intravitreal aflibercept in patients with diabetic macular edema (DME). Methods: We included 17 patients with DME, central retinal thickness (CRT) >300...

  5. Comparison of oxygen saturation values and measurement times by pulse oximetry in various parts of the body.

    Science.gov (United States)

    Yönt, Gülendam Hakverdioğlu; Korhan, Esra Akin; Khorshid, Leyla

    2011-11-01

    The aim of this study, which included 40 patients, was to compare the values pulse oximetry and the measurement times in various regions of the body. Data were analyzed using intraclass correlation coefficient test and paired-sample test. The confidence power value was found to be .81 for the comparison of oxygen saturation values by arterial blood gas analysis and measurement by the forehead probe. It was found that the time for oxygen saturation measurement using the forehead probe was shorter than those using the finger and toe probes. Copyright © 2011 Elsevier Inc. All rights reserved.

  6. Comparison of cerebral tissue oxygenation values in full term and preterm newborns by the simultaneous use of two near-infrared spectroscopy devices: an absolute and a relative trending oximeter

    Science.gov (United States)

    Szczapa, Tomasz; Karpiński, Łukasz; Moczko, Jerzy; Weindling, Michael; Kornacka, Alicja; Wróblewska, Katarzyna; Adamczak, Aleksandra; Jopek, Aleksandra; Chojnacka, Karolina; Gadzinowski, Janusz

    2013-08-01

    The aim of this study is to compare a two-wavelength light emitting diode-based tissue oximeter (INVOS), which is designed to show trends in tissue oxygenation, with a four-wavelength laser-based oximeter (FORE-SIGHT), designed to deliver absolute values of tissue oxygenation. Simultaneous values of cerebral tissue oxygenation (StO2) are measured using both devices in 15 term and 15 preterm clinically stable newborns on the first and third day of life. Values are recorded simultaneously in two periods between which oximeter sensor positions are switched to the contralateral side. Agreement between StO2 values before and after the change of sensor position is analyzed. We find that mean cerebral StO2 values are similar between devices for term and preterm babies, but INVOS shows StO2 values spread over a wider range, with wider standard deviations than shown by the FORE-SIGHT. There is relatively good agreement with a bias up to 3.5% and limits of agreement up to 11.8%. Measurements from each side of the forehead show better repeatability for the FORE-SIGHT monitor. We conclude that performance of the two devices is probably acceptable for clinical purposes. Both performed sufficiently well, but the use of FORE-SIGHT may be associated with tighter range and better repeatability of data.

  7. Evaluation of arterial oxygen saturation using RGB camera-based remote photoplethysmography

    Science.gov (United States)

    Nishidate, Izumi; Nakano, Kazuya; McDuff, Daniel; Niizeki, Kyuichi; Aizu, Yoshihisa; Haneishi, Hideaki

    2018-02-01

    Plethysmogram is the periodic variation in blood volume due to the cardiac pulse traveling through the body. Photo-plethysmograph (PPG) has been widely used to assess the cardiovascular system such as heart rate, blood pressure, cardiac output, vascular compliance. We have previously proposed a non-contact PPG imaging method using a digital red-green-blue camera. In the method, the Monte Carlo simulation for light transport is used to specify a relationship among the RGB-values and the concentrations of oxygenated hemoglobin (CHbO) and deoxygenated hemoglobin (CHbR). The total hemoglobin concentration (CHbT) can be calculated as a sum of CHbO and CHbR. Applying the fast Fourier transform (FFT) band pass filters to each pixel of the sequential images for CHbT along the time line, two-dimentional plethysmogram can be reconstructed. In this study, we further extend the method to imaging the arterial oxygen saturation (SaO2). The PPG signals for both CHbO and CHbR are extracted by the FFT band pass filter and the pulse wave amplitudes (PWAs) of CHbO and CHbR are calculated. We assume that the PWA for CHbO and that for CHbR are decreased and increased as SaO2 is decreased. The ratio of PWA for CHbO and that for CHbR are associated to the reference value of SaO2 measured by a commercially available pulse oximeter, which provide an empirical formula to estimate SaO2 from the PPG signal at each pixel of RGB image. In vivo animal experiments with rats during varying the fraction of inspired oxygen (FiO2) demonstrated the feasibility of the proposed method.

  8. Intra-dialytic blood oxygen saturation (SO2): association with dialysis hypotension (the SOGLIA Study).

    Science.gov (United States)

    Mancini, E; Perazzini, C; Gesualdo, L; Aucella, F; Limido, A; Scolari, F; Savoldi, S; Tramonti, M; Corazza, L; Atti, M; Severi, S; Bolasco, P; Santoro, A

    2017-12-01

    Intradialytic hypotension (IDH) has a dramatic impact on the main outcomes of dialysis patients. Early warning of hemodynamic worsening during dialysis would enable preventive measures to be taken. Blood oxygen saturation (SO 2 ) is used for hemodynamic monitoring in the critical care setting and may provide useful information about IDH onset. To evaluate whether short- and medium-term variations in the SO 2 signal (ST-SO 2var , MT-SO 2var ,) during dialysis are a predictor of IDH. In this 3-month observational cohort study, 51 hypotension-prone chronic hemodialysis (HD) patients, with vascular access by arteriovenous fistula (AVF) or central venous catheter (CVC), were enrolled. Continuous non-invasive blood SO 2 was monitored (fc = 0.2 Hz) by an optical sensor on the arterial line of the extracorporeal circulation; blood pressure (every 30 min), symptoms and their time of appearance were noted. Predictive power of IDH was expressed by the area under curve (AUC) sensitivity and specificity based on intradialytic variations in SO 2 . A total of 1290 HD sessions were analyzed. Overall, off-line ST-SO 2var analysis proved able to correctly predict IDH in 67 % of the sessions where IDH occurred. The best predictive performance was found in the presence of highly arterialized AVF (SO 2  > 95 %) (75 % sensitivity; AUC 0.825; p < 0.05). On the contrary, in sessions with CVC, IDH prediction proved more efficient by MT-SO 2var (AUC 0.575; p = 0.01). Intradialytic SO 2 variability could be a valid parameter to detect in advance the hemodynamic worsening that precedes IDH. Appropriate timely intervention could help prevent IDH onset.

  9. The Relationship between Oxygen Saturation and Color Alteration of a Compromised Skin Flap: Experimental Study on the Rabbit.

    Science.gov (United States)

    Prasetyono, Theddeus O H; Adianto, Senja

    2013-09-01

    The aim of this study was to collect important data on the time of oxygen saturation change in relation to skin flap color alteration using non-invasive pulse oximetry to evaluate its ability to provide continuous monitoring of skin flap perfusion. An experimental study on the monitoring of blood perfusion of 20 tube-island groin flaps of 10 male New Zealand rabbits was performed using pulse oximetry. The animals were randomly assigned to one of two groups representing a blockage of either arterial or venous blood flow. The oxygen saturation change and clinical color alteration were monitored from the beginning of vessel clamping until the saturation became undetectable. The result was analyzed by the t-test using SSPS ver. 10.0. The mean times from the vessel clamping until the saturation became undetectable were 20.19±2.13 seconds and 74.91±10.57 seconds for the artery and vein clamping groups, respectively. The mean time of the clinical alteration from the beginning of vein clamping was 34.5±11.72 minutes, while the alteration in flaps with artery clamping could not be detected until 2.5 hours after clamping. The use of neonate-type reusable flex sensor-pulse oximetry is objective and effective in early detection of arterial and vein blockage. It provides real-time data on vessel occlusion, which in turn will allow for early salvaging. The detection periods of both arterial occlusion and venous congestion are much earlier than the color alteration one may encounter clinically.

  10. The Relationship between Oxygen Saturation and Color Alteration of a Compromised Skin Flap: Experimental Study on the Rabbit

    Directory of Open Access Journals (Sweden)

    Theddeus O. H. Prasetyono

    2013-09-01

    Full Text Available BackgroundThe aim of this study was to collect important data on the time of oxygen saturation change in relation to skin flap color alteration using non-invasive pulse oximetry to evaluate its ability to provide continuous monitoring of skin flap perfusion.MethodsAn experimental study on the monitoring of blood perfusion of 20 tube-island groin flaps of 10 male New Zealand rabbits was performed using pulse oximetry. The animals were randomly assigned to one of two groups representing a blockage of either arterial or venous blood flow. The oxygen saturation change and clinical color alteration were monitored from the beginning of vessel clamping until the saturation became undetectable. The result was analyzed by the t-test using SSPS ver. 10.0.ResultsThe mean times from the vessel clamping until the saturation became undetectable were 20.19±2.13 seconds and 74.91±10.57 seconds for the artery and vein clamping groups, respectively. The mean time of the clinical alteration from the beginning of vein clamping was 34.5±11.72 minutes, while the alteration in flaps with artery clamping could not be detected until 2.5 hours after clamping.ConclusionsThe use of neonate-type reusable flex sensor-pulse oximetry is objective and effective in early detection of arterial and vein blockage. It provides real-time data on vessel occlusion, which in turn will allow for early salvaging. The detection periods of both arterial occlusion and venous congestion are much earlier than the color alteration one may encounter clinically.

  11. StoThermSolar - possible applications and practical experience with transparent thermal insulation compound systems; StoThermSolar - Anwendungsmoeglichkeiten und praktische Erfahrungen mit transparenten Waermedaemmverbundsystemen

    Energy Technology Data Exchange (ETDEWEB)

    Zwerger, M. [Sto AG, Stuehlingen (Germany)

    1996-11-01

    Sto AG has the motto `building conscientiously`. Consciousness of the environment acts as ethic for the firm. About 2000 employees develop, produce and market environmentally suitable product systems for facades, internal walls, ceilings and floors. They extend from paint and plaster, thermal insulation compound systems, concrete repair and acoustic systems to decorative profiles of old glass. (orig./HW) [Deutsch] `Bewusst Bauen` heisst das Leitwort der Sto AG. Umweltbewusstsein als Unternehmensethik. Rund 2000 Mitarbeiter entwickeln, produzieren und vermarkten umweltgerechte Produktsysteme fuer Fassade, Innenwand, Decke und Boden. Von Farben und Putzen, Waermedaemm-Verbundsystemen, Betoninstandsetzungs- oder Akustiksystemen bis zu Deco-Profilen aus Altglas. (orig./HW)

  12. The effect of tourniquet deflation on hemodynamics and regional cerebral oxygen saturation in aged patients undergoing total knee replacement surgery

    OpenAIRE

    Song, Inkyung; Kim, Dong Yeon; Kim, Youn Jin

    2012-01-01

    Background Inflation and deflation of a pneumatic tourniquet used in total knee replacement surgery induces various changes in patient's hemodynamic and metabolic status, which may result in serious complications, especially in aged patients. Near-infrared spectroscopy (NIRS) is a monitoring device designed to estimate the regional cerebral oxygen saturation. We evaluated the effect of tourniquet deflation on hemodynamics and regional cerebral oxygen saturation in aged patients undergoing tot...

  13. Effects of Cyanate and 2,3-Diphosphoglycerate on Sickling RELATIONSHIP TO OXYGENATION

    Science.gov (United States)

    Jensen, Michael; Bunn, H. Franklin; Halikas, George; Kan, Yuet Wai; Nathan, David G.

    1973-01-01

    Cyanate and 2,3-diphosphoglycerate (2,3-DPG) both influence the oxygen affinity of hemoglobin. The studies presented here concern the effects of these compounds on the sickling phenomenon. The inhibitory effect of cyanate on sickling is largely due to the fact that it increases the percentage of oxyhemoglobin S at a given oxygen tension. In addition, cyanate inhibits sickling by a mechanism that is independent of oxygenation. In this paper, we have demonstrated that the viscosity of carbamylated sickle blood was lower than that of non-carbamylated controls at the same oxygen saturation. Furthermore, carbamylation resulted in an increase in the minimum concentration of deoxy-sickle hemoglobin required for gelation. Like cyanate, 2,3-DPG affected sickling of intact erythrocytes by two mechanisms. Since 2,3-DPG decreases the percentage of oxyhemoglobin S at a given oxygen tension, sickling is enhanced. In addition, 2,3-DPG had a direct effect. When the intracellular 2,3-DPG concentration was increased in vitro, a greater percentage of cells were sickled at a given oxygen saturation. Conversely, sickling was inhibited in cells in which 2,3-DPG was artificially lowered. These data indicate that the enhancement of sickling by 2,3-DPG is in part independent of its influence on oxygen affinity. PMID:4729047

  14. [Tissue oxygen saturation in the critically ill patient].

    Science.gov (United States)

    Gruartmoner, G; Mesquida, J; Baigorri, F

    2014-05-01

    Hemodynamic resuscitation seeks to correct global macrocirculatory parameters of pressure and flow. However, current evidence has shown that despite the normalization of these global parameters, microcirculatory and regional perfusion alterations can persist, and these alterations have been independently associated with a poorer patient prognosis. This in turn has lead to growing interest in new technologies for exploring regional circulation and microcirculation. Near infra-red spectroscopy allows us to monitor tissue oxygen saturation, and has been proposed as a noninvasive, continuous and easy-to-obtain measure of regional circulation. The present review aims to summarize the existing evidence on near infra-red spectroscopy and its potential clinical role in the resuscitation of critically ill patients in shock. Copyright © 2013 Elsevier España, S.L. and SEMICYUC. All rights reserved.

  15. Evaluation of different near-infrared spectroscopy technologies for assessment of tissue oxygen saturation during a vascular occlusion test.

    Science.gov (United States)

    Steenhaut, Kevin; Lapage, Koen; Bové, Thierry; De Hert, Stefan; Moerman, Annelies

    2017-12-01

    An increasing number of NIRS devices are used to provide measurements of peripheral tissue oxygen saturation (S t O 2 ). The aim of the present study is to test the hypothesis that despite technological differences between devices, similar trend values will be obtained during a vascular occlusion test. The devices compared are NIRO-200NX, which measures S t O 2 and oxyhemoglobin by spatially resolved spectroscopy and the Beer-Lambert law, respectively, and INVOS 5100C and Foresight Elite, which both measure S t O 2 with the Beer-Lambert law, enhanced with the spatial resolution technique. Forty consenting adults scheduled for CABG surgery were recruited. The respective sensors of the three NIRS devices were applied over the brachioradial muscle. Before induction of anesthesia, 3 min of ischemia were induced by inflating a blood pressure cuff at the upper arm, whereafter cuff pressure was rapidly released. Tissue oxygenation measurements included baseline, minimum and maximum values, desaturation and resaturation slopes, and rise time. Comparisons between devices were performed with the Kruskal-Wallis test with post hoc Mann-Whitney pairwise comparisons. Agreement was evaluated using Bland-Altman plots. Oxyhemoglobin measured with NIRO responded faster than the other NIRS technologies to changes in peripheral tissue oxygenation (20 vs. 27-40 s, p ≤ 0.01). When comparing INVOS with Foresight, oxygenation changes were prompter (upslope 311 [92-523]%/min vs. 114[65-199]%/min, p ≤ 0.01) and more pronounced (minimum value 36 [21-48] vs. 45 [40-51]%, p ≤ 0.01) with INVOS. Significant differences in tissue oxygen saturation measurements were observed, both within the same device as between different devices using the same measurement technology.

  16. [Study of blood oxygen saturation, heart rate changes and plateau reaction of the Antarctic Kunlun station investigation team in different plateau environments].

    Science.gov (United States)

    Zhao, Shun-yun; Wu, Xin-min; Guo, Ya-min; Zhang, Shu-shun; An, Yan-ming; Li, Bing; Wang, Hao

    2013-06-11

    To explore the blood oxygen saturation and heart rate changes of the Antarctic explorers. During August 2010 to April 2011, the changes in blood oxygen saturation, heart rate and plateau reaction of 16 Antarctic expedition team in different plateau environments (Tibetan plateau versus Antarctic plateau) were monitored with the noninvasive pulse oximeter MD300-C. The extent of acute mountain sickness was determined according to the Lake Louise Consensus acute mountain reaction symptom scores and judgment method. The changes of blood oxygen saturation, heart rate at different altitudes of 110, 3650, 4300 m (96.8% ± 1.2%,89.1% ± 1.2%, 86.1% ± 2.0%, (75.0 ± 5.4) times/min, (104.0 ± 4.3) times/min, (113.0 ± 5.2) times/min,F = 214.155, 240.088,both P rate at different altitudes of 2000, 2500, 3000, 3500 and 4087 m(91.9% ± 1.3%,90.5% ± 1.3%,87.6% ± 1.4%,85.0% ± 1.8%,81.5% ± 2.2%, (85.9 ± 3.2) times/min, (90.6 ± 2.8) times/min, (97.8 ± 4.1) times/min, (102.0 ± 3.4) times/min, (106.3 ± 3.9) times/min, F = 105.418, 90.174, both P rate were both correlated with the risk of altitude sickness (r = -0.446 and 0.565, both P rate of the Antarctic explorers. And with the increases of altitude, the risk of altitude sickness gradually increases.

  17. Robotic Technologies for the Future Force - The ART STO

    National Research Council Canada - National Science Library

    Jaster, Jeffrey F

    2005-01-01

    .... The US Army's ARV Robotic Technologies (ART) Science and Technology Objective (STO) will develop a surrogate platform that will be used as a technology demonstrator for such robotic technologies...

  18. The effects of arterial carbon dioxide partial pressure and sevoflurane on capillary venous cerebral blood flow and oxygen saturation during craniotomy.

    Science.gov (United States)

    Klein, Klaus Ulrich; Glaser, Martin; Reisch, Robert; Tresch, Achim; Werner, Christian; Engelhard, Kristin

    2009-07-01

    Intraoperative routine monitoring of cerebral blood flow and oxygenation remains a technological challenge. Using the physiological principle of carbon dioxide reactivity of cerebral vasculature, we investigated a recently developed neuromonitoring device (oxygen-to-see, O2C device) for simultaneous measurements of regional cerebral blood flow (rvCBF), blood flow velocity (rvVelo), oxygen saturation (srvO2), and hemoglobin amount (rvHb) at the capillary venous level in patients subjected to craniotomy. Twenty-six neurosurgical patients were randomly assigned to anesthesia with 1.4% or 2.0% sevoflurane end-tidal concentration. After craniotomy, a fiberoptic probe was applied on a macroscopically healthy surface of cerebral tissue next to the site of surgery. Simultaneous measurements in 2 and 8 mm cerebral depth were performed in each patient during lower (35 mm Hg) and higher (45 mm Hg) levels (random order) of arterial carbon dioxide partial pressure (PaCO2). The principle of these measurements relies on the combination of laser-Doppler flowmetry (rvCBF, rvVelo) and photo-spectrometry (srvO2, rvHb). Linear models were fitted to test changes of end points (rvCBF, rvVelo, srvO2, rvHb) in response to lower and higher levels of PaCO2, 1.4% and 2.0% sevoflurane end-tidal concentration, and 2 and 8 mm cerebral depth. RvCBF and rvVelo were elevated by PaCO2 independent of sevoflurane concentration in 2 and 8 mm depth of cerebral tissue (P oxygen was decreased by elevated PaCO2. Unchanged levels of rvHb signify that there was no blood loss during measurements. Data suggest that the device allows detection of local changes in blood flow and oxygen saturation in response to different PaCO2 levels in predominant venous cerebral microvessels.

  19. An effective XML based name mapping mechanism within StoRM

    International Nuclear Information System (INIS)

    Corso, E; Forti, A; Ghiselli, A; Magnoni, L; Zappi, R

    2008-01-01

    In a Grid environment the naming capability allows users to refer to specific data resources in a physical storage system using a high level logical identifier. This logical identifier is typically organized in a file system like structure, a hierarchical tree of names. Storage Resource Manager (SRM) services map the logical identifier to the physical location of data evaluating a set of parameters as the desired quality of services and the VOMS attributes specified in the requests. StoRM is a SRM service developed by INFN and ICTP-EGRID to manage file and space on standard POSIX and high performing parallel and cluster file systems. An upcoming requirement in the Grid data scenario is the orthogonality of the logical name and the physical location of data, in order to refer, with the same identifier, to different copies of data archived in various storage areas with different quality of service. The mapping mechanism proposed in StoRM is based on a XML document that represents the different storage components managed by the service, the storage areas defined by the site administrator, the quality of service they provide and the Virtual Organization that want to use the storage area. An appropriate directory tree is realized in each storage component reflecting the XML schema. In this scenario StoRM is able to identify the physical location of a requested data evaluating the logical identifier and the specified attributes following the XML schema, without querying any database service. This paper presents the namespace schema defined, the different entities represented and the technical details of the StoRM implementation

  20. Photoplethysmographic signals and blood oxygen saturation values during artificial hypothermia in healthy volunteers

    International Nuclear Information System (INIS)

    Shafique, M; Kyriacou, P A

    2012-01-01

    Pulse oximetry utilizes the technique of photoplethysmography to estimate arterial oxygen saturation (SpO 2 ) values. During hypothermia, the amplitude of the photoplethysmograph (PPG) is compromised which can lead to inaccurate estimation of SpO 2 . A new mutlimode PPG/pulse oximeter sensor was developed to investigate the behaviour of PPGs during conditions of induced hypothermia (hand immersed in an ice bath). PPG measurements from 20 volunteers were conducted and SpO 2 values were estimated at all stages of the experiment. Good quality PPG signals were observed from the majority of the volunteers at almost all hand temperatures. At low temperature ranges, from 13 to 21 °C, the failure rate to estimate SpO 2 values from the multimode transreflectance PPG sensor was 2.4% as compared to the commercial pulse oximeter with a failure rate of 70%. (paper)

  1. Blood gases and oxygen saturation response to active cycle of breathing techniques in COPD patients during phase I of cardiac rehabilitation

    International Nuclear Information System (INIS)

    Sheraz, S.; Siddiqi, F.A.

    2015-01-01

    Objective: To determine the effectiveness of active cycle of breathing techniques (ACBTs) on arterial blood gases (ABG), oxygen saturation and other vitals including chest expansion, heart rate, and respiratory rate in COPD patients during phase I of cardiac rehabilitation program after open heart surgery. Methodology: In this experimental study, sample size chosen was 100 patients, randomly divided into experimental (n=50) and control (n=50) groups. Pre-test values of ABG, oxygen saturation, chest expansion, respiratory rate, and heart rate of the participants were taken. Then, conventional physical therapy including spirometry was performed 2 hourly by the control group whereas the experimental group performed ACBTs along with spirometry twice a day for a period of one week. Participants were re-assessed after one week treatment. Results: There was highly significant difference (p<0.01) in pre-test and post-test values of PCO/sub 2/ and oxygen saturation in experimental group as compared to control group. The results of bicarbonate values, base excess and heart rate were statistically significant (p<0.01) in control group and there was no significant difference (p>0.05) in experimental group. The values of pH, chest expansion and respiratory rate were highly significant (p<0.01) in both control as well as experimental group. Conclusion: ACBT was more effective to decrease post CABG complication as compared to conventional chest physical therapy. Some parameters like bicarbonate values, base excess and heart rate did not show improvement with ACBT. (author)

  2. Low pO2 Contributes to Potential Error in Oxygen Saturation Calculations Using a Point-of-Care Assay.

    Science.gov (United States)

    Gunsolus, Ian L; Love, Sara A; Kohl, Louis P; Schmidt, Martin; Apple, Fred S

    2017-12-20

    The present study addressed the accuracy of calculated oxygen saturation (sO2) using point-of-care (POC) testing compared with measured values on a blood gas analyzer. In total, 3,323 sO2 values were measured in 1,180 patients using a CO-oximeter (ABL 800 Flex; Radiometer, Copenhagen, Denmark). Measured parameters were then used to calculate an expected sO2 for the POC method (Abbott i-STAT; Abbott POC, Princeton, NJ). Cases in which calculated sO2 differed from measured sO2 by 10% or more were analyzed. Of the 3,323 comparisons performed, 260 (8%) showed discrepancies (± ≥10%) between measured and calculated sO2 values. Ninety-four of discrepant measurements (245 of 260) occurred when pO2 was less than 50 mm Hg. pH and bicarbonate distributions shifted to lower values in discrepant vs nondiscrepant cases. Our results suggest that the likelihood of discrepant sO2 is 27% among patients with pO2 less than 50 mm Hg. Direct measurement of sO2 by CO-oximetry is strongly suggested in this clinical scenario. © American Society for Clinical Pathology, 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com

  3. A pilot study of a new spectrophotometry device to measure tissue oxygen saturation.

    Science.gov (United States)

    Abel, Gemma; Allen, John; Drinnan, Michael

    2014-09-01

    Tissue oxygen saturation (SO2) measurements have the potential for far wider use than at present but are limited by device availability and portability for many potential applications. A device based on a small, low-cost general-purpose spectrophotometer (the Harrison device) might facilitate wider use. The aim of this study was to compare the Harrison device with a commercial instrument, the LEA O2C.Measurements were carried out on the forearm and finger of 20 healthy volunteers, using a blood pressure cuff on the upper arm to induce different levels of oxygenation. Repeatability of both devices was assessed, and the Bland-Altman method was used to assess agreement between them.The devices showed agreement in overall tracking of changes in SO2. Test-retest agreement for the Harrison device was worse than for O2C, with SD repeatability of 10.6% (forearm) or 18.6% (finger). There was no overall bias between devices, but mean (SD) difference of 1.2 (11.8%) (forearm) or 4.4 (11.5%) (finger) were outside of a clinically acceptable range.Disagreements were attributed to the stability of the Harrison probe and the natural SO2 variations across the skin surface increasing the random error. Therefore, though not equivalent to the LEA O2C, a probe redesign and averaged measurements may help establish the Harrison device as a low cost alternative.

  4. A pilot study of a new spectrophotometry device to measure tissue oxygen saturation

    International Nuclear Information System (INIS)

    Abel, Gemma; Allen, John; Drinnan, Michael

    2014-01-01

    Tissue oxygen saturation (SO2) measurements have the potential for far wider use than at present but are limited by device availability and portability for many potential applications. A device based on a small, low-cost general-purpose spectrophotometer (the Harrison device) might facilitate wider use. The aim of this study was to compare the Harrison device with a commercial instrument, the LEA O2C. Measurements were carried out on the forearm and finger of 20 healthy volunteers, using a blood pressure cuff on the upper arm to induce different levels of oxygenation. Repeatability of both devices was assessed, and the Bland–Altman method was used to assess agreement between them. The devices showed agreement in overall tracking of changes in SO2. Test–retest agreement for the Harrison device was worse than for O2C, with SD repeatability of 10.6% (forearm) or 18.6% (finger). There was no overall bias between devices, but mean (SD) difference of 1.2 (11.8%) (forearm) or 4.4 (11.5%) (finger) were outside of a clinically acceptable range. Disagreements were attributed to the stability of the Harrison probe and the natural SO2 variations across the skin surface increasing the random error. Therefore, though not equivalent to the LEA O2C, a probe redesign and averaged measurements may help establish the Harrison device as a low cost alternative. (paper)

  5. Comparison of oxygen saturation levels in patients receiving Technegas by the conventional unassisted method vs. the positive ventilation delivery system (PVDS)

    International Nuclear Information System (INIS)

    Dobson, M.P.; Leiper, C.A.; Lee, K.; Dixson, H.

    2000-01-01

    Full text: The purpose of this study is to compare oxygen saturation levels (SaO 2 ) in 289 patients undergoing conventional lung ventilation scintigraphy (control group) and 27 patients undergoing Positive Ventilation Delivery System (PVDS). The 27 patients where selected as their conventional method of inhalation proved to be inadequate or non-diagnostic. The patients underwent a second ventilation using PVDS, which improved the diagnostic quality of the ventilation image and assisted in clinical management decisions. Some patients in both the PVDS and the control group experienced a transient lowering in their SaO 2 . The mean initial SaO 2 in the control group did not fall below 94.9% and in the PVDS group measured 90.6%. 93% (25/27) of patients in the PVDS group were assessed as non CO 2 retaining, and received oxygen at 10L/min during Technegas inhalation. The mean trough saturation in the PVDS group was 91.7% which was significantly higher than that of the control group (86.9%). No patient in either group experienced any significant complication attributed to the transient tall in SaO 2 during technegas administration. We conclude that oxygen supplied as part of the PVDS system ameliorates the transient reduction in SaO 2 seen during standard Technegas administration. Copyright (2000) The Australian and New Zealand Society of Nuclear Medicine Inc

  6. Oxygen and disorder effect in the magnetic properties of manganite films

    Energy Technology Data Exchange (ETDEWEB)

    Sirena, M. E-mail: sirenam@ib.cnea.gov.ar; Haberkorn, N.; Granada, M.; Steren, L.B.; Guimpel, J

    2004-05-01

    We have made a systematic study of the magnetic properties of low doped manganite films submitted to different oxygenation treatments. We have found that oxygenation dynamics depends critically of the strain field in the sample. The T{sub C} and the Mr increase as the oxygen content is increased. A decrease of the coercive field of the LSMO-STO films was observed, indicating that annealing treatments increase the oxygen content reducing oxygen vacancies.

  7. Oxygen and disorder effect in the magnetic properties of manganite films

    International Nuclear Information System (INIS)

    Sirena, M.; Haberkorn, N.; Granada, M.; Steren, L.B.; Guimpel, J.

    2004-01-01

    We have made a systematic study of the magnetic properties of low doped manganite films submitted to different oxygenation treatments. We have found that oxygenation dynamics depends critically of the strain field in the sample. The T C and the Mr increase as the oxygen content is increased. A decrease of the coercive field of the LSMO-STO films was observed, indicating that annealing treatments increase the oxygen content reducing oxygen vacancies

  8. Near-infrared spectroscopy assessment of microvasculature detects difference in lower limb vascular responsiveness in obese compared to lean individuals.

    Science.gov (United States)

    Soares, Rogério Nogueira; Murias, Juan M

    2018-07-01

    Microvascular dysfunction is an early complication in obesity-related cardiovascular disease (CVD) that can lead to changes in hemodynamic function and endothelial cell expression throughout the vasculature that is vessel specific. This study aimed to evaluate whether the near-infrared spectroscopy (NIRS) combined with a vascular occlusion (VOT) assessment was capable of detecting differences in vascular responsiveness within the microvasculature of the lower limb between lean and obese individuals. Twenty lean (BMI = 21.6 ± 1.3) and 17 obese individuals (BMI = 33.9 ± 1.1) participated in the study. Individuals underwent a VOT (5 min of baseline, 5 min of occlusion, and 8 min following cuff release) and vascular responsiveness was evaluated by the Slope 2 (Slope 2 StO 2 ) and the area under the curve (StO 2AUC ) of oxygen saturation (StO 2 ) signal during reperfusion. The difference between the minimal and the maximal value of StO 2 was calculated as the Amplitude of the StO 2 response. The Slope 2 StO 2 of the obese individuals was smaller (0.68 ± 0.07%·s -1 ) than the Slope 2 StO 2 of the lean individuals (1.08 ± 0.13%·s -1 ;P lean individuals (1708 ± 168%·s -1 ; P lean ones (30.4 ± 2.9 vs 21.6 ± 1.3 StO 2 (%), respectively; P lean individuals (r = 0.745; P lean and obese individuals. Copyright © 2018 Elsevier Inc. All rights reserved.

  9. Assessment of Arterial Oxygen Saturation by Pulse Oximetry Before, During and After Electroconvulsive Therapy

    Directory of Open Access Journals (Sweden)

    SH Tarig

    2006-07-01

    Full Text Available Introduction & Objective: Electroconvulsive therapy (ECT is used widely in psychiatric practice. The goal of anesthesia for ECT is the prevention of complications such as discomfort, fractures, aspiration of gastric contents and hypoxia. However, general anesthesia can cause some adverse effects as hypoxia. Prevention and treatment of hypoxia is important due to its undesirable effects on seizure duration and cardiovascular system. This study was designed to detect the incidence and probable times of desaturation in patients receiving ECT. Materials & Methods: This prospective randomized clinical trial was carried out on 100 patients (18-50 y/o with ASA I or II who were scheduled for ECT. After pre-oxygenation and similar anesthesia induction the patients received ECT. The patients were ventilated by oxygen and face masked until the return of their spontaneous respiration with adequate tidal volume and respiratory rate. Then they were transferred to recovery room where there was no oxygen supplementation. Oxygen saturation was measured by a Nell core pulse oximeter and was recorded at six stages: before and after anesthesia induction, during ECT, after ECT, 5 minutes after entering recovery room and before leaving there. The data were analyzed by standard statistical tests using SPSS software Results: Data analysis revealed that desaturation was not noticed at any stage except for the 5th stage (5 minutes after entering recovery room, when 13% of patients developed Sao2% less than 90%. Also there was a significant difference between Sao2% of patients between this stage (5th and other stages (p<0.001. Conclusion: According to our findings, appropriate oxygen supplementation and pulse oximetry monitoring during recovery period after ECT can be recommend

  10. [Design of Oxygen Saturation, Heart Rate, Respiration Rate Detection System Based on Smartphone of Android Operating System].

    Science.gov (United States)

    Zhu, Mingshan; Zeng, Bixin

    2015-03-01

    In this paper, we designed an oxygen saturation, heart rate, respiration rate monitoring system based on smartphone of android operating system, physiological signal acquired by MSP430 microcontroller and transmitted by Bluetooth module.

  11. EFFECTIVENESS OF AUTOGENIC DRAINAGE VERSUS POSTURAL DRAINAGE ON OXYGEN SATURATION IN PATIENTS WITH CHRONIC BRONCHITIS WITH 15 MINUTES POST THERAPY

    Directory of Open Access Journals (Sweden)

    V. Kiran

    2014-12-01

    Full Text Available Background: Patients with COPD will have more amount of secretions. To clear the secretions by using of different bronchial hygiene techniques like postural drainage and autogenic drainage technique, manual hyperventilation technique ,active cycle breathing technique .Hence in this study to compare the short-term effects of postural drainage with clapping (PD and autogenic drainage (AD on level of oxygen saturation in blood, and amount of sputum recovery. Methodology: The study was done on 60 patients with COPD. Dividing Patients into two group and patients were treated with PD or AD in separate Groups. The effectiveness of the treatment was measured up to 6 days. Pulse oximetry was monitored and sputum was collected immediately after treatment and 15 minutes following each treatment. Results: The results of the study shown that there was significant difference in the amount of sputum recovered with AD (14.0±3.5 g vs PD (24.4±3.0 g and significant differences in Oxygen saturation; during PD fell from 93.3±0.7% to 91.2±0.8% (p<0.01 and required 15 min following treatment to return to baseline. Oxygen saturation did not fall during AD and increased to gradually following complete treatment days (baseline, 93.3±0.8%; p<0.01. Conclusion: Hence this study concludes that Autogenic drainage is more effective in improving spo2 in COPD & does not cause a sudden fall in spo2 as occurs in Postural drainage immediately after therapy. And it can be better tolerated by patients with COPD while producing fewer benefits in sputum clearance. In concern to mean amount of secretion removal Postural is found to be more effective

  12. Accuracy of pulse oximetry in detection of oxygen saturation in patients admitted to the intensive care unit of heart surgery: comparison of finger, toe, forehead and earlobe probes.

    Science.gov (United States)

    Seifi, Sohila; Khatony, Alireza; Moradi, Gholamreza; Abdi, Alireza; Najafi, Farid

    2018-01-01

    Heart surgery patients are more at risk of poor peripheral perfusion, and peripheral capillary oxygen saturation (SpO2) measurement is regular care for continuous analysis of blood oxygen saturation in these patients. With regard to controversial studies on accuracy of the current pulse oximetry probes and lack of data related to patients undergoing heart surgery, the present study was conducted to determine accuracy of pulse oximetry probes of finger, toe, forehead and earlobe in detection of oxygen saturation in patients admitted to intensive care units for coronary artery bypass surgery. In this clinical trial, 67 patients were recruited based on convenience sampling method among those admitted to intensive care units for coronary artery bypass surgery. The SpO2 value was measured using finger, toe, forehead and earlobe probes and then compared with the standard value of arterial oxygen saturation (SaO2). Data were entered into STATA-11 software and analyzed using descriptive, inferential and Bland-Altman statistical analyses. Highest and lowest correlational mean values of SpO2 and SaO2 were related to finger and earlobe probes, respectively. The highest and lowest agreement of SpO2 and SaO2 were related to forehead and earlobe probes. The SpO2 of earlobe probes due to lesser mean difference, more limited confidence level and higher agreement ration with SaO2 resulted by arterial blood gas (ABG) analysis had higher accuracy. Thus, it is suggested to use earlobe probes in patients admitted to the intensive care unit for coronary artery bypass surgery. Registration of this trial protocol has been approved in Iranian Registry of Clinical Trials at 2018-03-19 with reference IRCT20100913004736N22. "Retrospectively registered."

  13. Oxygen saturation in children with and without obstructive sleep apnea using the phone-oximeter.

    Science.gov (United States)

    Garde, Ainara; Karlen, Walter; Dehkordi, Parastoo; Wensley, David; Ansermino, J Mark; Dumont, Guy A

    2013-01-01

    Obstructive sleep apnea (OSA) in children can lead to daytime sleepiness, growth failure and developmental delay. Polysomnography (PSG), the gold standard to diagnose OSA is highly resource intensive and is confined to the sleep laboratory. In this study we propose to identify children with OSA using blood oxygen saturation (SpO2) obtained from the Phone Oximeter. This portable, in-home device is able to monitor patients over multiple nights, causes less sleep disturbance and facilitates a more natural sleep pattern. The proposed algorithm analyzes the SpO2 signal in the time and frequency domain using a 90-s sliding window. Three spectral parameters are calculated from the power spectral density (PSD) to evaluate the modulation in the SpO2 due to the oxyhemoblobin desaturations. The power P, slope S in the discriminant band (DB), and ratio R between P and total power are calculated for each window. Tendency and variability indices, number of SpO2 desaturations and time spent under 2% or 3% of baseline saturation level are computed for each time window. The statistical distribution of the temporal evolution of all parameters is analyzed to identify 68 children, 30 with OSA and 38 without OSA (nonOSA). This characterization was evaluated by a feature selection based on a linear discriminant. The combination of temporal and spectral parameters provided the best leave one out crossvalidation results with an accuracy of 86.8%, a sensitivity of 80.0%, and a specificity of 92.1% using only 5 parameters. The median of R, mean of P and S and mean and standard deviation of the number of desaturations below 3% of baseline saturation level, were the most representative parameters. Hence, a better knowledge of SpO2 dynamics could help identifying children with OSA with the Phone Oximeter.

  14. Near-simultaneous hemoglobin saturation and oxygen tension maps in mouse brain using an AOTF microscope.

    Science.gov (United States)

    Shonat, R D; Wachman, E S; Niu, W; Koretsky, A P; Farkas, D L

    1997-09-01

    A newly developed microscope using acousto-optic tunable filters (AOTFs) was used to generate in vivo hemoglobin saturation (SO2) and oxygen tension (PO2) maps in the cerebral cortex of mice. SO2 maps were generated from the spectral analysis of reflected absorbance images collected at different wavelengths, and PO2 maps were generated from the phosphorescence lifetimes of an injected palladium-porphyrin compound using a frequency-domain measurement. As the inspiratory O2 was stepped from hypoxia (10% O2), through normoxia (21% O2), to hyperoxia (60% O2), measured SO2 and PO2 levels rose accordingly and predictably throughout. A plot of SO2 versus PO2 in different arterial and venous regions of the pial vessels conformed to the sigmoidal shape of the oxygen-hemoglobin dissociation curve, providing further validation of the two mapping procedures. The study demonstrates the versatility of the AOTF microscope for in vivo physiologic investigation, allowing for the generation of nearly simultaneous SO2 and PO2 maps in the cerebral cortex, and the frequency-domain detection of phosphorescence lifetimes. This class of study opens up exciting new possibilities for investigating the dynamics of hemoglobin and O2 binding during functional activation of neuronal tissues.

  15. Nanoparticle-enhanced spectral photoacoustic tomography: effect of oxygen saturation and tissue heterogeneity

    Science.gov (United States)

    Vogt, William C.; Jia, Congxian; Wear, Keith A.; Garra, Brian S.; Pfefer, T. Joshua

    2016-03-01

    Molecular imaging for breast cancer detection, infectious disease diagnostics and preclinical animal research may be achievable through combined use of targeted exogenous agents - such as nanoparticles - and spectral Photoacoustic Tomography (PAT). However, tissue heterogeneity can alter fluence distributions and acoustic propagation, corrupting measured PAT absorption spectra and complicating in vivo nanoparticle detection and quantitation. Highly absorptive vascular structures represent a common confounding factor, and variations in vessel hemoglobin saturation (SO2) may alter spectral content of signals from adjacent/deeper regions. To evaluate the impact of this effect on PAT nanoparticle detectability, we constructed heterogeneous phantoms with well-characterized channel-inclusion geometries and biologically relevant optical and acoustic properties. Phantoms contained an array of tubes at several depths filled with hemoglobin solutions doped with varying concentrations of gold nanorods with an absorption peak at 780 nm. Both overlying and target network SO2 was tuned using sodium dithionite. Phantoms were imaged from 700 to 900 nm using a custom PAT system comprised of a tunable pulsed laser and a research-grade ultrasound system. Recovered nanoparticle spectra were analyzed and compared with results from both spectrophotometry and PAT data from waterimmersed tubes containing blood and nanoparticle solutions. Results suggested that nanoparticle selection for a given PAT application should take into account expected oxygenation states of both target blood vessel and background tissue oxygenation to achieve optimal performance.

  16. Preparation of the La0.8Sr0.2MnO3 films on STO and LAO substrates by excimer laser-assisted metal organic deposition using the KrF laser

    International Nuclear Information System (INIS)

    Tsuchiya, T.; Daoudi, K.; Manabe, T.; Yamaguchi, I.; Kumagai, T.

    2007-01-01

    La 0.8 Sr 0.2 MnO 3 films were prepared on SrTiO 3 (STO) and LaAlO 3 (LAO) substrates using excimer laser-assisted metal organic deposition (ELAMOD). For the LAO substrate, no epitaxial La 0.8 Sr 0.2 MnO 3 film was obtained by laser irradiation in the fluence range from 60 to 110 mJ/cm 2 with heating at 500 deg. C. On the other hand, an epitaxial La 0.8 Sr 0.2 MnO 3 film on the STO substrate was formed by laser irradiation in the fluence range from 60 to 100 mJ/cm 2 with heating at 500 deg. C. To optimize the electrical properties for an IR sensor, the effects of the laser fluence, the irradiation time and the film thickness on the temperature dependence of the resistance and temperature coefficient of resistance (TCR: defined as 1/R.(dR/dT)) of the LSMO films were investigated. An LSMO film on the STO substrate that showed the maximum TCR of 3.9% at 265 K was obtained by the ELAMOD process using the KrF laser

  17. Effects of targeting lower versus higher arterial oxygen saturations on death or disability in preterm infants.

    Science.gov (United States)

    Askie, Lisa M; Darlow, Brian A; Davis, Peter G; Finer, Neil; Stenson, Ben; Vento, Maximo; Whyte, Robin

    2017-04-11

    The use of supplemental oxygen in the care of extremely preterm infants has been common practice since the 1940s. Despite this, there is little agreement regarding which oxygen saturation (SpO₂) ranges to target to maximise short- or long-term growth and development, while minimising harms. There are two opposing concerns. Lower oxygen levels (targeting SpO₂ at 90% or less) may impair neurodevelopment or result in death. Higher oxygen levels (targeting SpO₂ greater than 90%) may increase severe retinopathy of prematurity or chronic lung disease.The use of pulse oximetry to non-invasively assess neonatal SpO₂ levels has been widespread since the 1990s. Until recently there were no randomised controlled trials (RCTs) that had assessed whether it is better to target higher or lower oxygen saturation levels in extremely preterm infants, from birth or soon thereafter. As a result, there is significant international practice variation and uncertainty remains as to the most appropriate range to target oxygen saturation levels in preterm and low birth weight infants. 1. What are the effects of targeting lower versus higher oxygen saturation ranges on death or major neonatal and infant morbidities, or both, in extremely preterm infants?2. Do these effects differ in different types of infants, including those born at a very early gestational age, or in those who are outborn, without antenatal corticosteroid coverage, of male sex, small for gestational age or of multiple birth, or by mode of delivery? We used the standard search strategy of Cochrane Neonatal to search the Cochrane Central Register of Controlled Trials (CENTRAL 2016, Issue 4), MEDLINE via PubMed (1966 to 11 April 2016), Embase (1980 to 11 April 2016) and CINAHL (1982 to 11 April 2016). We also searched clinical trials databases, conference proceedings and the reference lists of retrieved articles for randomised controlled trials. Randomised controlled trials that enrolled babies born at less than 28

  18. Higher cerebral oxygen saturation may provide higher urinary output during continuous regional cerebral perfusion

    Directory of Open Access Journals (Sweden)

    Tomoyasu Takahiro

    2008-10-01

    Full Text Available Abstract Objective We examined the hypothesis that higher cerebral oxygen saturation (rSO2 during RCP is correlated with urinary output. Methods Between December 2002 and August 2006, 12 patients aged 3 to 61 days and weighing 2.6 to 3.4 kg underwent aortic arch repair with RCP. Urinary output and rSO2 were analyzed retrospectively. Data were assigned to either of 2 groups according to their corresponding rSO2: Group A (rSO2 ≦ 75% and Group B (rSO2 Results Seven and 5 patients were assigned to Group A and Group B, respectively. Group A was characterized by mean radial arterial pressure (37.9 ± 9.6 vs 45.8 ± 7.8 mmHg; P = 0.14 and femoral arterial pressure (6.7 ± 6.1 vs 20.8 ± 14.6 mmHg; P = 0.09 compared to Group B. However, higher urinary output during CPB (1.03 ± 1.18 vs 0.10 ± 0.15 ml·kg-1·h-1; P = 0.03. Furthermore our results indicate that a higher dose of Chlorpromazine was used in Group A (2.9 ± 1.4 vs 1.7 ± 1.0 mg/kg; P = 0.03. Conclusion Higher cerebral oxygenation may provide higher urinary output due to higher renal blood flow through collateral circulation.

  19. The Effects of Walking or Walking-with-Poles Training on Tissue Oxygenation in Patients with Peripheral Arterial Disease

    Directory of Open Access Journals (Sweden)

    Eileen G. Collins

    2012-01-01

    Full Text Available This randomized trial proposed to determine if there were differences in calf muscle StO2 parameters in patients before and after 12 weeks of a traditional walking or walking-with-poles exercise program. Data were collected on 85 patients who were randomized to a traditional walking program ( or walking-with-poles program ( of exercise training. Patients walked for 3 times weekly for 12 weeks. Seventy-one patients completed both the baseline and the 12-week follow-up progressive treadmill tests ( traditional walking and walking-with-poles. Using the near-infrared spectroscopy measures, StO2 was measured prior to, during, and after exercise. At baseline, calf muscle oxygenation decreased from % prior to the treadmill test to % at peak exercise. The time elapsed prior to reaching nadir StO2 values increased more in the traditional walking group when compared to the walking-with-poles group. Likewise, absolute walking time increased more in the traditional walking group than in the walking-with-poles group. Tissue oxygenation decline during treadmill testing was less for patients assigned to a 12-week traditional walking program when compared to those assigned to a 12-week walking-with-poles program. In conclusion, the 12-week traditional walking program was superior to walking-with-poles in improving tissue deoxygenation in patients with PAD.

  20. [Monitorization of the effects of spinal anaesthesia on cerebral oxygen saturation in elder patients using near-infrared spectroscopy].

    Science.gov (United States)

    Kusku, Aysegul; Demir, Guray; Cukurova, Zafer; Eren, Gulay; Hergunsel, Oya

    2014-01-01

    Central blockage provided by spinal anaesthesia enables realization of many surgical procedures, whereas hemodynamic and respiratory changes influence systemic oxygen delivery leading to the potential development of series of problems such as cerebral ischemia, myocardial infarction and acute renal failure. This study was intended to detect potentially adverse effects of hemodynamic and respiratory changes on systemic oxygen delivery using cerebral oxymetric methods in patients who underwent spinal anaesthesia. Twenty-five ASA I-II Group patients aged 65-80 years scheduled for unilateral inguinal hernia repair under spinal anaesthesia were included in the study. Following standard monitorization baseline cerebral oxygen levels were measured using cerebral oximetric methods. Standardized Mini Mental Test (SMMT) was applied before and after the operation so as to determine the level of cognitive functioning of the cases. Using a standard technique and equal amounts of a local anaesthetic drug (15mg bupivacaine 5%) intratechal blockade was performed. Mean blood pressure (MBP), maximum heart rate (MHR), peripheral oxygen saturation (SpO2) and cerebral oxygen levels (rSO2) were preoperatively monitored for 60min. Pre- and postoperative haemoglobin levels were measured. The variations in data obtained and their correlations with the cerebral oxygen levels were investigated. Significant changes in pre- and postoperative measurements of haemoglobin levels and SMMT scores and intraoperative SpO2 levels were not observed. However, significant variations were observed in intraoperative MBP, MHR and rSO2 levels. Besides, a correlation between variations in rSO2, MBP and MHR was determined. Evaluation of the data obtained in the study demonstrated that post-spinal decline in blood pressure and also heart rate decreases systemic oxygen delivery and adversely effects cerebral oxygen levels. However, this downward change did not result in deterioration of cognitive functioning

  1. Monitorization of the effects of spinal anaesthesia on cerebral oxygen saturation in elder patients using near-infrared spectroscopy.

    Science.gov (United States)

    Kusku, Aysegul; Demir, Guray; Cukurova, Zafer; Eren, Gulay; Hergunsel, Oya

    2014-01-01

    Central blockage provided by spinal anaesthesia enables realization of many surgical procedures, whereas hemodynamic and respiratory changes influence systemic oxygen delivery leading to the potential development of series of problems such as cerebral ischemia, myocardial infarction and acute renal failure. This study was intended to detect potentially adverse effects of hemodynamic and respiratory changes on systemic oxygen delivery using cerebral oxymetric methods in patients who underwent spinal anaesthesia. Twenty-five ASA I-II Group patients aged 65-80 years scheduled for unilateral inguinal hernia repair under spinal anaesthesia were included in the study. Following standard monitorization baseline cerebral oxygen levels were measured using cerebral oximetric methods. Standardized Mini Mental Test (SMMT) was applied before and after the operation so as to determine the level of cognitive functioning of the cases. Using a standard technique and equal amounts of a local anaesthetic drug (15mg bupivacaine 5%) intratechal blockade was performed. Mean blood pressure (MBP), maximum heart rate (MHR), peripheral oxygen saturation (SpO2) and cerebral oxygen levels (rSO2) were preoperatively monitored for 60min. Pre- and postoperative haemoglobin levels were measured. The variations in data obtained and their correlations with the cerebral oxygen levels were investigated. Significant changes in pre- and postoperative measurements of haemoglobin levels and SMMT scores and intraoperative SpO2 levels were not observed. However, significant variations were observed in intraoperative MBP, MHR and rSO2 levels. Besides, a correlation between variations in rSO2, MBP and MHR was determined. Evaluation of the data obtained in the study demonstrated that post-spinal decline in blood pressure and also heart rate decreases systemic oxygen delivery and adversely effects cerebral oxygen levels. However, this downward change did not result in deterioration of cognitive functioning

  2. Measurement of the branching fractions of the $B^0_s\\to J/\\psi\\eta$, $B^0_s\\to J/\\psi\\eta^{\\prime}$ and $B^0\\to J\\psi\\omega$ decays in the LHCb experiment

    CERN Document Server

    Savrina, Daria

    First evidence of the $B^0\\to J/\\psi\\omega$ decay is found and the $B^0_s\\to J/\\psi\\eta$ and $B^0_s\\to J/\\psi\\eta^{\\prime}$ decays are studied using a dataset corresponding to an integrated luminosity of 1.0 $\\mathrm{fb}^{-1}$ collected by the LHCb experiment in proton-proton collisions at a center-of-mass energy of $\\sqrt{s} = 7$ TeV. Branching fractions of these decays are measured relative to that of the $B^0\\to J/\\psi\\rho^0$ decay. All the channels under study contain photons in the final state. Precise determination of photons energies is essential for accurate measurement of the decays branching fractions. So, an auxiliary task was a regular calibration of the LHCb electromagnetic calorimeter with neutral pions. Values obtained for the $B^0_s\\to J/\\psi\\eta$ and $B^0_s\\to J/\\psi\\eta^{\\prime}$ decays branching fractions, as well as a ratio of these values, are found to be in a good agreement with both theoretical predictions and results of previous measurements. The $B^0\\to J/\\psi\\omega$ decay is seen for...

  3. Closed Loop Control of Oxygen Delivery and Oxygen Generation

    Science.gov (United States)

    2017-08-01

    were used for this study and were connected via a USB cable to allow communication. The ventilator was modified to allow closed loop control of oxygen...connected via a USB cable to allow communication. The ventilator was modified to allow closed loop control of oxygen based on the oxygen saturation...2017-4119, 28 Aug 2017. oximetry (SpO2) and intermittent arterial blood sampling for arterial oxygen tension (partial pressure of oxygen [PaO2]) and

  4. Dependence of diameters and oxygen saturation of retinal vessels on visual field damage and age in primary open-angle glaucoma.

    Science.gov (United States)

    Ramm, Lisa; Jentsch, Susanne; Peters, Sven; Sauer, Lydia; Augsten, Regine; Hammer, Martin

    2016-05-01

    To investigate the interrelationship between the oxygen supply of the retina and its regulation with the severity of primary open-angle glaucoma (POAG). Central retinal artery (CRAE) and vein (CRVE) diameters and oxygen saturation of peripapillary retinal vessels in 41 patients suffering from POAG (64.1 ± 12.9 years) and 40 healthy volunteers (63.6 ± 14.1 years) were measured using the retinal vessel analyzer. All measures were taken before and during flicker light stimulation. The mean retinal nerve fiber layer thickness (RNFLT) was determined by OCT and the visual field mean defect (MD) was identified using perimetry. In glaucoma patients, CRAE (r = -0.48 p = 0.002) and CRVE (r = -0.394 p = 0.014) at baseline were inversely related to MD, while arterial and venous oxygen saturation showed no significant dependence on the severity of the damage. However, the flicker light-induced change in arterio-venous difference in oxygen saturation was correlated with the MD (r = 0.358 p = 0.027). The diameters of arteries and veins at baseline decreased with reduction of the mean RNFLT (arteries: r = 0.718 p field loss, may be explained by a reduction of the retinal metabolic demand with progressive loss of neuronal tissue in glaucoma. © 2015 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

  5. Study of Al-Si Alloy Oxygen Saturation on Its Microstructure and Mechanical Properties.

    Science.gov (United States)

    Finkelstein, Arkady; Schaefer, Arseny; Chikova, Оlga; Borodianskiy, Konstantin

    2017-07-11

    One of the main goals of modern materials research is obtaining different microstructures and studying their influence on the mechanical properties of metals; aluminum alloys are particularly of interest due to their advanced performance. Traditionally, their required properties are obtained by alloying process, modification, or physical influence during solidification. The present work describes a saturation of the overheated AlSi₇Fe₁ casting alloy by oxides using oxygen blowing approach in overheated alloy. Changes in metals' microstructural and mechanical properties are also described in the work. An Al 10 SiFe intermetallic complex compound was obtained as a preferable component to Al₂O₃ precipitation on it, and its morphology was investigated by scanning electron microscopy. The mechanical properties of the alloy after the oxygen blowing treatment are discussed in this work.

  6. Performance evaluation of photoacoustic oximetry imaging systems using a dynamic blood flow phantom with tunable oxygen saturation

    Science.gov (United States)

    Vogt, William C.; Zhou, Xuewen; Andriani, Rudy; Wear, Keith A.; Garra, Brian S.; Pfefer, Joshua

    2018-02-01

    Photoacoustic Imaging (PAI) is an emerging technology with strong potential for broad clinical applications from breast cancer detection to cerebral monitoring due to its ability to compute maps of blood oxygen saturation (SO2) distribution in deep tissues using multispectral imaging. However, no well-validated consensus test methods currently exist for evaluating oximetry-specific performance characteristics of PAI devices. We have developed a phantombased flow system capable of rapid SO2 adjustment to serve as a test bed for elucidation of factors impacting SO2 measurement and quantitative characterization of device performance. The flow system is comprised of a peristaltic pump, membrane oxygenator, oxygen and nitrogen gas, and in-line oxygen, pH, and temperature sensors that enable real-time estimation of SO2 reference values. Bovine blood was delivered through breast-relevant tissue phantoms containing vessel-mimicking fluid channels, which were imaged using a custom multispectral PAI system. Blood was periodically drawn for SO2 measurement in a clinical-grade CO-oximeter. We used this flow phantom system to evaluate the impact of device parameters (e.g.,wavelength-dependent fluence corrections) and tissue parameters (e.g. fluid channel depth, blood SO2, spectral coloring artifacts) on oximetry measurement accuracy. Results elucidated key challenges in PAI oximetry and device design trade-offs, which subsequently allowed for optimization of system performance. This approach provides a robust benchtop test platform that can support PAI oximetry device optimization, performance validation, and clinical translation, and may inform future development of consensus test methods for performance assessment of photoacoustic oximetry imaging systems.

  7. Oxygen Saturation Surrounding Deep Water Formation Events in the Labrador Sea From Argo-O2 Data

    Science.gov (United States)

    Wolf, Mitchell K.; Hamme, Roberta C.; Gilbert, Denis; Yashayaev, Igor; Thierry, Virginie

    2018-04-01

    Deep water formation supplies oxygen-rich water to the deep sea, spreading throughout the ocean by means of the global thermohaline circulation. Models suggest that dissolved gases in newly formed deep water do not come to equilibrium with the atmosphere. However, direct measurements during wintertime convection are scarce, and the controls over the extent of these disequilibria are poorly quantified. Here we show that, when convection reached deeper than 800 m, oxygen in the Labrador Sea was consistently undersaturated at -6.1% to -7.6% at the end of convection. Deeper convection resulted in greater undersaturation, while convection ending later in the year resulted in values closer to equilibrium, from which we produce a predictive relationship. We use dissolved oxygen data from six profiling Argo floats in the Labrador Sea between 2003 and 2016, allowing direct observations of wintertime convection. Three of the six optode oxygen sensors displayed substantial average in situ drift of -3.03 μmol O2 kg-1 yr-1 (-0.94% O2 yr-1), which we corrected to stable deepwater oxygen values from repeat ship surveys. Observations of low oxygen intrusions during restratification and a simple mixing calculation demonstrate that lateral processes act to lower the oxygen inventory of the central Labrador Sea. This suggests that the Labrador Sea is a net sink for atmospheric oxygen, but uncertainties in parameterizing gas exchange limit our ability to quantify the net uptake. Our results constrain the oxygen concentration of newly formed Labrador Sea Water and allow more precise estimates of oxygen utilization and nutrient regeneration in this water mass.

  8. State-of-art application of near infrared spectroscopy for functional diagnostics in neonatology

    International Nuclear Information System (INIS)

    Wolf, M.; Paiziev, A.

    2013-01-01

    The present brief review is devoted to application of near infra-red spectroscopy (NIRS) for early diagnostics of human brain injury. The number of commercially accessible NIRS instruments, and accordingly their users, increases but the precision of measurements and their reproducibility from the clinical point of view essentially depend on used algorithms, a kind of the NIRS-instrument, sensors, which frequently leads to the different values of the measurable parameters of blood oxygen saturation (StO 2 ). We present some commercially accessible NIRS instruments for control of an oxygen saturation degree in human blood, first of all in neonatology, on the basis of absorption and scattering of near infra-red light at human tissue chromophores. The results of clinical investigations of different NIRS-spectrometers for measurements of in-vivo new-born child' blood saturation are presented as well. (authors)

  9. Reduced deep regional cerebral venous oxygen saturation in hemodialysis patients using quantitative susceptibility mapping.

    Science.gov (United States)

    Chai, Chao; Liu, Saifeng; Fan, Linlin; Liu, Lei; Li, Jinping; Zuo, Chao; Qian, Tianyi; Haacke, E Mark; Shen, Wen; Xia, Shuang

    2018-02-01

    Cerebral venous oxygen saturation (SvO 2 ) is an important indicator of brain function. There was debate about lower cerebral oxygen metabolism in hemodialysis patients and there were no reports about the changes of deep regional cerebral SvO 2 in hemodialysis patients. In this study, we aim to explore the deep regional cerebral SvO 2 from straight sinus using quantitative susceptibility mapping (QSM) and the correlation with clinical risk factors and neuropsychiatric testing . 52 hemodialysis patients and 54 age-and gender-matched healthy controls were enrolled. QSM reconstructed from original phase data of 3.0 T susceptibility-weighted imaging was used to measure the susceptibility of straight sinus. The susceptibility was used to calculate the deep regional cerebral SvO 2 and compare with healthy individuals. Correlation analysis was performed to investigate the correlation between deep regional cerebral SvO 2 , clinical risk factors and neuropsychiatric testing. The deep regional cerebral SvO 2 of hemodialysis patients (72.5 ± 3.7%) was significantly lower than healthy controls (76.0 ± 2.1%) (P deep regional cerebral SvO 2 in patients. The Mini-Mental State Examination (MMSE) scores of hemodialysis patients were significantly lower than healthy controls (P deep regional cerebral SvO 2 did not correlate with MMSE scores (P = 0.630). In summary, the decreased deep regional cerebral SvO 2 occurred in hemodialysis patients and dialysis duration, parathyroid hormone, hematocrit, hemoglobin and red blood cell may be clinical risk factors.

  10. Oxygen dosing the surface of SrTiO{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Dudy, L.; Scheiderer, P.; Schuetz, P.; Gabel, J.; Buchwald, M.; Sing, M.; Claessen, R. [Physikalisches Institut, Universitaet Wuerzburg (Germany); Denlinger, J.D. [Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA, 94270 (United States); Schlueter, C.; Lee, T.L. [Diamond Light Source Ltd., Didcot, Oxfordshire (United Kingdom)

    2015-07-01

    The highly mobile two-dimensional electron system (2DES) on the surface of the insulating SrTiO{sub 3}(STO) offers exciting perspectives for advanced material design. This 2DES resides in a depletion layer caused by oxygen deficiency of the surface. With photoemission spectroscopy, we monitor the appearance of quasi-particle weight (QP) at the Fermi energy and oxygen vacancy induced states in the band gap (IG). Both, QP and IG weight, increase and decrease respectively upon exposure to extreme ultraviolet (XUV) light and in-situ oxygen dosing. By a proper adjustment of oxygen dosing, any intermediate state can be stabilized providing full control over the charge carrier density. From a comparison of the charge carrier concentrations obtained from an analysis of core-level spectra and the Fermi-surface volume, we conclude on a spatially inhomogeneous surface electronic structure with at least two different phases.

  11. In-vivo continuous monitoring of mixed venous oxygen saturation by photoacoustic transesophageal echocardiography (Conference Presentation)

    Science.gov (United States)

    Li, Li; Subramaniam, Balachundhar; Aguirre, Aaron D.; Andrawes, Michael N.; Tearney, Guillermo J.

    2016-02-01

    Mixed venous oxygen saturation (SvO2), measured from pulmonary arteries, is a gold-standard measure of the dynamic balance between the oxygen supply and demand in the body. In critical care, continuous monitoring of SvO2 plays a vital role in early detection of circulatory shock and guiding goal-oriented resuscitation. In current clinical practice, SvO2 is measured by invasive pulmonary artery catheters (PAC), which are associated with a 10% risk of severe complications. To address the unmet clinical need for a non-invasive SvO2 monitor, we are developing a new technology termed photoacoustic transesophageal echocardiography (PA-TEE). PA-TEE integrates transesophageal echocardiography with photoacoustic oximetry, and enables continuous assessment of SvO2 through an esophageal probe that can be inserted into the body in a minimally invasive manner. We have constructed a clinically translatable PA-TEE prototype, which features a mobile OPO laser, a modified ultrasonography console and a dual-modality esophageal probe. Comprised of a rotatable acoustic array detector, a flexible optical fiber bundle and a light-integrating acoustic lens, the oximetric probe has an outer diameter smaller than 15 mm and will be tolerable for most patients. Through custom-made C++/Qt software, our device acquires and displays ultrasonic and photoacoustic images in real time to guide the deployment of the probe. SvO2 is calculated on-line and updated every second. PA-TEE has now been used to evaluate SvO2 in living swine. Our findings show that changing the fraction of oxygen in the inspired gas modulates SvO2 measured by PA-TEE. Statistic comparison between SvO2 measurements from PA-TEE in vivo the gold-standard laboratorial analysis on blood samples drawn from PACs will be presented.

  12. A new fibre optic pulse oximeter probe for monitoring splanchnic organ arterial blood oxygen saturation.

    Science.gov (United States)

    Hickey, M; Samuels, N; Randive, N; Langford, R; Kyriacou, P A

    2012-12-01

    A new, continuous method of monitoring splanchnic organ oxygen saturation (SpO(2)) would make the early detection of inadequate tissue oxygenation feasible, reducing the risk of hypoperfusion, severe ischaemia, and, ultimately, death. In an attempt to provide such a device, a new fibre optic based reflectance pulse oximeter probe and processing system were developed followed by an in vivo evaluation of the technology on seventeen patients undergoing elective laparotomy. Photoplethysmographic (PPG) signals of good quality and high signal-to-noise ratio were obtained from the small bowel, large bowel, liver and stomach. Simultaneous peripheral PPG signals from the finger were also obtained for comparison purposes. Analysis of the amplitudes of all acquired PPG signals indicated much larger amplitudes for those signals obtained from splanchnic organs than those obtained from the finger. Estimated SpO(2) values for splanchnic organs showed good agreement with those obtained from the finger fibre optic probe and those obtained from a commercial device. These preliminary results suggest that a miniaturized 'indwelling' fibre optic sensor may be a suitable method for pre-operative and post-operative evaluation of splanchnic organ SpO(2) and their health. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  13. Influence of the depth of sedation on regional cerebral oxygen saturation monitoring in neurosurgery of supratentorial gliomas

    Directory of Open Access Journals (Sweden)

    ZHANG Kai⁃ying

    2012-12-01

    Full Text Available Objective To investigate the influence on regional cerebral oxygen saturation (rScO2 of sedation depth during anesthesia induction and maintenance in supratentorial glioma resections. Methods Thirty patients with Ⅰ - Ⅱ supratentorial glioma (graded by American Society of Anesthesiologists underwent elective supratentorial glioma resection were included in this study. Rocuronium, sufentanil and propofol were used for anesthesia induction. After trachea cannula, total intravenous anesthesia (TIVA was maintained with plasma concentration of propofol 2.80-3.20 μg/ml and remifentanil 0.10-0.20 μg/(kg·min. Thirty groups of rScO2, bispectral index (BIS, mean arterial pressure (MAP and heart rate (HR were recorded continuously till the incision. Results During anesthesia induction, BIS decreased along with the infusion of anesthetics, and there was significant negative correlation between BIS and rScO2 (r = ⁃0.803, P = 0.001. During anesthesia maintenance, rScO2 and BIS were not significantly related (r = 0.147, P = 0.396. Conclusion The rScO2 monitoring can reflect the influence of sedation depth on cerebral oxygen delivery and consumption balance during supratentorial glioma resection under TIVA.

  14. The 30-second rule: the effects of prolonged intubation attempts on oxygen saturation and heart rate in preterm infants in the delivery room.

    Science.gov (United States)

    Wozniak, Madeline; Arnell, Kathy; Brown, Melissa; Gonzales, Sarah; Lazarus, Danielle; Rich, Wade; Katheria, Anup

    2018-04-01

    A duration of 30 seconds has been shown to improve the success rate of intubation attempts without any decompensation. There is limited data regarding the detrimental effects of prolonged intubation attempts in preterm infants. The aim was to determine the effect of prolonged intubation attempts on heart rate and oxygen saturation in preterm infants. We retrospectively reviewed videos and physiologic data collected during delivery room (DR) resuscitations. Infants who had a functioning pulse oximeter at the time of intubation in the delivery room were analyzed using video and analog recordings. The duration of the intubation attempt was defined as the time the laryngoscope blade was in the infant's mouth. Prolonged intubations were defined as intubations over 30 seconds. Baseline heart rate and saturations were defined as the heart rate and saturation immediately prior to the intubation attempt. Video recording was used to determine time laryngoscope was in the mouth, what other procedures were performed, and whether there was recovery between attempts. Analog data including heart rate, airway pressure and saturation was also recorded. There were 52 intubation attempts in 28 infants. The median (IQR) birth weight and gestational age were 795 (705, 972) grams and 25 (25, 27) weeks. The duration of an intubation attempt was 35 (27, 46) seconds with number of attempts 2 (1, 2). There were 34 intubation attempts greater than 30 seconds (prolonged group) and 18 attempts less than or equal to 30 seconds (short group). Longer attempts did not affect intubation success (successful 34 [25,37] seconds vs. unsuccessful 41[29, 53] seconds; P=0.05). Infants in the prolonged group had a greater decrease in oxygen saturation percentage from baseline (5±8 percent, short intubation group and 13±27 prolonged intubation group; P=0.004). There was also a significant decrease in heart rate beats per minute between the two groups (6±9 in the short intubation group and 23±29

  15. Chemisorption of oxygen and subsequent reactions on low index surfaces of β-Mo2C

    DEFF Research Database (Denmark)

    Shi, Xue Rong; Wang, Shengguang; Wang, Jianguo

    2016-01-01

    to the carbon vacancy were identified. We examined the effect of oxygen coverage on the morphology of β-Mo2C by plotting the equilibrium crystal shape. Thermodynamic effect of temperature and reactant or product pressure on the CO/CO2 desorption were investigated. The CO/CO2 desorption is more favorable...... at the saturated oxygen coverage than the low oxygen coverage thermodynamically. The subsequent oxygen diffusion to the carbon vacancy after CO/CO2 desorption may happen depending on the surfaces and oxygen coverage....

  16. Diffuse optical measurements of head and neck tumor hemodynamics for early prediction of radiation therapy (Conference Presentation)

    Science.gov (United States)

    Dong, Lixin; Kudrimoti, Mahesh; Irwin, Daniel; Chen, Li; Shang, Yu; Li, Xingzhe; Stevens, Scott D.; Shelton, Brent J.; Yu, Guoqiang

    2016-03-01

    Radiation therapy is a principal modality for head and neck cancers and its efficacy depends on tumor hemodynamics. Our laboratory developed a hybrid diffuse optical instrument allowing for simultaneous measurements of tumor blood flow and oxygenation. In this study, the clinically involved cervical lymph node was monitored by the hybrid instrument once a week over the treatment period of seven weeks. Based on treatment outcomes within one year, patients were classified into a complete response group (CR) and an incomplete response group (IR) with remote metastasis and/or local recurrence. A linear mixed models was used to compare tumor hemodynamic responses to the treatment between the two groups. Interestingly, we found that human papilloma virus (HPV-16) status largely affected tumor hemodynamic responses. For HPV-16 negative tumors, significant differences in blood flow index (BFI, p = 0.007) and reduced scattering coefficient (μs', p = 0.0005) were observed between the two groups; IR tumors exhibited higher μs' values and a continuous increase in BFI over the treatment period. For HPV-16 positive tumors, oxygenated hemoglobin concentration ([HbO2]) and blood oxygen saturation (StO2) were significant different (p = 0.003 and 0.01, respectively); IR group showed lower [HbO2] and StO2. Our results imply HPV-16 negative tumors with higher density of vasculature (μs') and higher blood flow show poor responses to radiotherapy and HPV-16 positive tumors with lower tissue oxygenation level (lower StO2 and [HbO2]) exhibit poor treatment outcomes. Our diffuse optical measurements show the great potential for early prediction of radiotherapy in head and neck cancers.

  17. Oxygen and SO2 Consumption Rates in White and Rosé Wines: Relationship with and Effects on Wine Chemical Composition.

    Science.gov (United States)

    Carrascón, Vanesa; Bueno, Mónica; Fernandez-Zurbano, Purificación; Ferreira, Vicente

    2017-11-01

    This Article addresses the study of O 2 and SO 2 consumption rates of white and rosé wines, their relationship to the initial chemical composition, and their effects on the chemical changes experienced by wine during oxidation. Eight wines were subjected to five consecutive air-saturation cycles. O 2 was monitored periodically; SO 2 , color, and antioxidant indexes were determined after each cycle, and the initial and final compositions of the wines were thoroughly determined. Wines consumed oxygen at progressively decreasing rates. In the last cycles, after a strong decrease, consistent increases of oxygen levels were seen. Oxygen consumption rates were satisfactorily modeled, being proportional to wine copper, quercetin, and kaempherol contents and negatively proportional to cinnamic acids. SO 2 consumption rates were highly diverse between wines and were positively related to free SO 2 , Mn, and pH, among others. In the last saturations, SO 2 consumption took place regardless of O 2 consumption, implying that SO 2 should reduce chemical species oxidized in previous saturations. Some volatile phenols seem to be the end point of radical-mediated oxidation of polyphenols taking place preferably in the first saturation.

  18. RAPID COMMUNICATION: A novel time frequency-based 3D Lissajous figure method and its application to the determination of oxygen saturation from the photoplethysmogram

    Science.gov (United States)

    Addison, Paul S.; Watson, James N.

    2004-11-01

    We present a novel time-frequency method for the measurement of oxygen saturation using the photoplethysmogram (PPG) signals from a standard pulse oximeter machine. The method utilizes the time-frequency transformation of the red and infrared PPGs to derive a 3D Lissajous figure. By selecting the optimal Lissajous, the method provides an inherently robust basis for the determination of oxygen saturation as regions of the time-frequency plane where high- and low-frequency signal artefacts are to be found are automatically avoided.

  19. Cerebral oxygenation is associated with neurodevelopmental outcome of preterm children at age 2 to 3 years

    NARCIS (Netherlands)

    Verhagen, Elise A.; Van Braeckel, Koenraad N. J. A.; van der Veere, Christa N.; Groen, Henk; Dijk, Peter H.; Hulzebos, Christian V.; Bos, Arend F.

    AIM: The aim of the study was to determine whether regional cerebral tissue oxygen saturation (rc SO2 ) and fractional tissue oxygen extraction (FTOE), using near-infrared spectroscopy, are associated with neurodevelopmental outcome of preterm infants. METHOD: We measured rc SO2 on days 1, 2, 3, 4,

  20. Minimum K_2,3-saturated Graphs

    OpenAIRE

    Chen, Ya-Chen

    2010-01-01

    A graph is K_{2,3}-saturated if it has no subgraph isomorphic to K_{2,3}, but does contain a K_{2,3} after the addition of any new edge. We prove that the minimum number of edges in a K_{2,3}-saturated graph on n >= 5 vertices is sat(n, K_{2,3}) = 2n - 3.

  1. Intracapillary HbO2 saturations in murine tumours and human tumour xenografts measured by cryospectrophotometry: relationship to tumour volume, tumour pH and fraction of radiobiologically hypoxic cells.

    Science.gov (United States)

    Rofstad, E K; Fenton, B M; Sutherland, R M

    1988-05-01

    Frequency distributions for intracapillary HbO2 saturation were determined for two murine tumour lines (KHT, RIF-1) and two human ovarian carcinoma xenograft lines (MLS, OWI) using a cryospectrophotometric method. The aim was to search for possible relationships between HbO2 saturation status and tumour volume, tumour pH and fraction of radiobiologically hypoxic cells. Tumour pH was measured by 31P NMR spectroscopy. Hypoxic fractions were determined from cell survival curves for tumours irradiated in vivo and assayed in vitro. Tumours in the volume range 100-4000 mm3 were studied and the majority of the vessels were found to have HbO2 saturations below 10%. The volume-dependence of the HbO2 frequency distributions differed significantly among the four tumour lines; HbO2 saturation status decreased with increasing tumour volume for the KHT, RIF-1 and MLS lines and was independent of tumour volume for the OWI line. The data indicated that the rate of decrease in HbO2 saturation status during tumour growth was related to the rate of development of necrosis. The volume-dependence of tumour pH was very similar to that of the HbO2 saturation status for all tumour lines. Significant correlations were therefore found between HbO2 saturation status and tumour pH, both within tumour lines and across the four tumour lines, reflecting that the volume-dependence of both parameters probably was a compulsory consequence of reduced oxygen supply conditions during tumour growth. Hypoxic fraction increased during tumour growth for the KHT, RIF-1 and MLS lines and was volume-independent for the OWI line, suggesting a relationship between HbO2 saturation status and hypoxic fraction within tumour lines. However, there was no correlation between these two parameters across the four tumour lines, indicating that the hypoxic fraction of a tumour is not determined only by the oxygen supply conditions; other parameters may also be important, e.g. oxygen diffusivity, rate of oxygen

  2. Near-infrared spectroscopy can detect differences in vascular responsiveness to a hyperglycaemic challenge in individuals with obesity compared to normal-weight individuals.

    Science.gov (United States)

    Soares, Rogério Nogueira; Reimer, Raylene A; Alenezi, Zaid; Doyle-Baker, Patricia K; Murias, Juan Manuel

    2018-01-01

    To examine whether the near-infrared spectroscopy combined with vascular occlusion test technique could detect differences in vascular responsiveness during hyperglycaemia between normal-weight individuals and individuals with obesity. A total of 16 normal-weight individuals (body mass index, 21.3 ± 1.7 kg/m 2 ) and 13 individuals with obesity (body mass index, 34.4 ± 2.0 kg/m 2 ) were submitted to five vascular occlusion tests (Pre, 30, 60, 90 and 120 min after glucose challenge). Vascular responsiveness was determined by the Slope 2 (Slope 2 StO 2 ) and the area under the curve (StO 2AUC ) of oxygen saturation derived from near-infrared spectroscopy-vascular occlusion test. The Slope 2 StO 2 increased from 1.07 ± 0.16%/s (Pre) to 1.53 ± 0.21%/s at 90 min ( p obese it increased from 0.71 ± 0.09%/s (Pre) to 0.92 ± 0.14%/s at 60 min ( p obesity. Near-infrared spectroscopy-vascular occlusion test technique was capable of detecting differences in vascular responsiveness during hyperglycaemia between normal-weight individuals and individuals with obesity.

  3. The Effect of Chronic Hypercapnia on Oxygen Affinity and 2, 3 Diphosphoglycerate as Related to Submarine Exposure

    Science.gov (United States)

    The relationship between oxygen affinity and 2,3 diphosphoglycerate (2,3 DPG) in the red cell has been studied in chronic hypercapnia induced by...initial values after seven days of exposure. Both oxygen half-saturation pressure (P50) and the level of 2,3 DPG of the red cells followed the time

  4. SLB-STO-D ANALYSIS REPORT: MODELING AND SIMULATION ANALYSIS OF FUEL, WATER, AND WASTE REDUCTIONS IN BASE CAMPS: 50, 300, AND 1000 PERSONS

    Science.gov (United States)

    2017-08-21

    EXECUTIVE SUMMARY The report covers work done for the Sustainability Logistics Basing – Science and Technology Objective – Demonstration (SLB-STO-D) 1...intentionally left blank 1 SUSTAINABILITY LOGISTICS-BASING SCIENCE AND TECHNOLOGY OBJECTIVE – DEMONSTRATION SLB-STO-D ANALYSIS REPORT MODELING AND...TECHNICAL REPORT AD ________________ NATICK/TR-17/023 SLB-STO-D ANALYSIS

  5. Effects of blood transfusion on oxygen extraction ratio and central venous saturation in children after cardiac surgery.

    Science.gov (United States)

    Nasser, Bana; Tageldein, Mohmad; AlMesned, Abdulrahman; Kabbani, Mohammad

    2017-01-01

    Red blood cell transfusion is common in critically ill children after cardiac surgery. Since the threshold for hemoglobin (Hb) transfusion need is not well defined, the threshold Hb level at which dependent critical oxygen uptake-to-delivery (VO2-DO2) status compensation is uncertain. To assess the effects of blood transfusion on the oxygen extraction ratio (O2ER) and central venous oxygen saturation (ScvO2) to identify a critical O2ER value that could help us determine the critical need for blood transfusion. Prospective, observational cohort study. Cardiac Surgical Intensive Care Unit at Prince Sultan Cardiac Center in Qassim, Saudi Arabia. Between January 2013 and December 2015, we included all children with cardiac disease who underwent surgery and needed a blood transfusion. Demographic and laboratory data with physiological parameters before and 1 and 6 hours after transfusion were recorded and O2ER before and 6 hours after transfusion was computed. Cases were divided into two groups based on O2ER: Patients with increased O2ER (O2ER > 40%) and normal patients without increased O2ER (O2ER transfusion. Changes in O2ER and ScvO2 following blood transfusion. Of 103 patients who had blood transfusion, 75 cases had normal O2ER before transfusion while 28 cases had increased O2ER before transfusion. Following blood transfusion, O2ER and ScvO2 improved in the group that had increased O2ER before transfusion, but not in the group that had normal O2ER before transfusion. The clinical and hemodynamic indicators O2ER and ScvO2 may be considered as markers that can indicate a need for blood transfusion. The limitation of this study is the small number of patients that had increased O2ER before transfusion. There were few available variables to assess oxygen consumption.

  6. High-affinity hemoglobin and blood oxygen saturation in diving emperor penguins.

    Science.gov (United States)

    Meir, Jessica U; Ponganis, Paul J

    2009-10-01

    The emperor penguin (Aptenodytes forsteri) thrives in the Antarctic underwater environment, diving to depths greater than 500 m and for durations longer than 23 min. To examine mechanisms underlying the exceptional diving ability of this species and further describe blood oxygen (O2) transport and depletion while diving, we characterized the O2-hemoglobin (Hb) dissociation curve of the emperor penguin in whole blood. This allowed us to (1) investigate the biochemical adaptation of Hb in this species, and (2) address blood O2 depletion during diving, by applying the dissociation curve to previously collected partial pressure of O2 (PO2) profiles to estimate in vivo Hb saturation (SO2) changes during dives. This investigation revealed enhanced Hb-O2 affinity (P50=28 mmHg, pH 7.5) in the emperor penguin, similar to high-altitude birds and other penguin species. This allows for increased O2 at low blood PO2 levels during diving and more complete depletion of the respiratory O2 store. SO2 profiles during diving demonstrated that arterial SO2 levels are maintained near 100% throughout much of the dive, not decreasing significantly until the final ascent phase. End-of-dive venous SO2 values were widely distributed and optimization of the venous blood O2 store resulted from arterialization and near complete depletion of venous blood O2 during longer dives. The estimated contribution of the blood O2 store to diving metabolic rate was low and highly variable. This pattern is due, in part, to the influx of O2 from the lungs into the blood during diving, and variable rates of tissue O2 uptake.

  7. Switchable diode effect in oxygen vacancy-modulated SrTiO{sub 3} single crystal

    Energy Technology Data Exchange (ETDEWEB)

    Pan, Xinqiang; Shuai, Yao; Wu, Chuangui; Luo, Wenbo; Sun, Xiangyu; Zeng, Huizhong; Bai, Xiaoyuan; Gong, Chaoguan; Jian, Ke; Zhang, Wanli [University of Electronic Science and Technology of China, State Key Laboratory of Electronic Thin Films and Integrated Devices, Chengdu (China); Zhang, Lu; Guo, Hongliang [University of Electronic Science and Technology of China, The Center for Robotics, Chengdu (China); Tian, Benlang [26th Institute of China Electronics Technology Group Corporation, Chongqing (China)

    2017-09-15

    SrTiO{sub 3} (STO) single crystal wafer was annealed in vacuum, and co-planar metal-insulator-metal structure of Pt/Ti/STO/Ti/Pt were formed by sputtering Pt/Ti electrodes onto the surface of STO after annealing. The forming-free resistive switching behavior with self-compliance property was observed in the sample. The sample showed switchable diode effect, which is explained by a simple model that redistribution of oxygen vacancies (OVs) under the external electric field results in the formation of n-n{sup +} junction or n{sup +}-n junction (n donated n-type semiconductor; n{sup +} donated heavily doped n-type semiconductor). The self-compliance property is also interpreted by the formation of n-n{sup +}/n{sup +}-n junction caused by the migration of the OVs under the electric field. (orig.)

  8. Dual-wavelength photothermal optical coherence tomography for blood oxygen saturation measurement

    Science.gov (United States)

    Yin, Biwei; Kuranov, Roman V.; McElroy, Austin B.; Milner, Thomas E.

    2013-03-01

    We report design and demonstration of a dual wavelength photothermal (DWP) optical coherence tomography (OCT) system for imaging of a phantom microvessel and measurement of hemoglobin oxygen saturation (SO2) level. The DWP-OCT system contains a swept-source (SS) two-beam phase-sensitive (PhS) OCT system (1060 nm) and two intensity modulated photothermal excitation lasers (770 nm and 800 nm). The PhS-OCT probe beam (1060 nm) and photothermal excitation beams are combined into one single-mode optical fiber. A galvanometer based two-dimensional achromatic scanning system is designed to provide 14 μm lateral resolution for the PhS-OCT probe beam (1060 nm) and 13 μm lateral resolution for photothermal excitation beams. DWP-OCT system's sensitivity is 102 dB, axial resolution is 13 μm in tissue and uses a real-time digital dispersion compensation algorithm. Noise floor for optical pathlength measurements is 300 pm in the signal frequency range (380-400 Hz) of photothermal modulation frequencies. Blood SO2 level is calculated from measured optical pathlength (op) signal in a 300 μm diameter microvessel phantom introduced by the two photothermal excitation beams. En-face and B-scan images of a phantom microvessel are recorded, and six blood samples' SO2 levels are measured using DWP-OCT and compared with values provided by a commercial blood oximeter. A mathematical model indicates thermal diffusion introduces a systematic artifact that over-estimates SO2 values and is consistent with measured data.

  9. Inhibition of NAPDH Oxidase 2 (NOX2 Prevents Oxidative Stress and Mitochondrial Abnormalities Caused by Saturated Fat in Cardiomyocytes.

    Directory of Open Access Journals (Sweden)

    Leroy C Joseph

    Full Text Available Obesity and high saturated fat intake increase the risk of heart failure and arrhythmias. The molecular mechanisms are poorly understood. We hypothesized that physiologic levels of saturated fat could increase mitochondrial reactive oxygen species (ROS in cardiomyocytes, leading to abnormalities of calcium homeostasis and mitochondrial function. We investigated the effect of saturated fat on mitochondrial function and calcium homeostasis in isolated ventricular myocytes. The saturated fatty acid palmitate causes a decrease in mitochondrial respiration in cardiomyocytes. Palmitate, but not the monounsaturated fatty acid oleate, causes an increase in both total cellular ROS and mitochondrial ROS. Palmitate depolarizes the mitochondrial inner membrane and causes mitochondrial calcium overload by increasing sarcoplasmic reticulum calcium leak. Inhibitors of PKC or NOX2 prevent mitochondrial dysfunction and the increase in ROS, demonstrating that PKC-NOX2 activation is also required for amplification of palmitate induced-ROS. Cardiomyocytes from mice with genetic deletion of NOX2 do not have palmitate-induced ROS or mitochondrial dysfunction. We conclude that palmitate induces mitochondrial ROS that is amplified by NOX2, causing greater mitochondrial ROS generation and partial depolarization of the mitochondrial inner membrane. The abnormal sarcoplasmic reticulum calcium leak caused by palmitate could promote arrhythmia and heart failure. NOX2 inhibition is a potential therapy for heart disease caused by diabetes or obesity.

  10. Regional oxygen saturation index (rSO2) in brachioradialis and deltoid muscle. Correlation and prognosis in patients with respiratory sepsis.

    Science.gov (United States)

    Rodríguez, A; Claverias, L; Marín, J; Magret, M; Rosich, S; Bodí, M; Trefler, S; Pascual, S; Gea, J

    2015-03-01

    To compare oxygen saturation index (rSO2) obtained simultaneously in two different brachial muscles. Prospective and observational study. Intensive care unit. Critically ill patients with community-acquired pneumonia. Two probes of NIRS device (INVOS 5100) were simultaneously placed on the brachioradialis (BR) and deltoid (D) muscles. rSO2 measurements were recorded at baseline (ICU admission) and at 24h. Demographic and clinical variables were registered. Pearson's correlation coefficient was used to assess the association between continuous variables. The consistency of the correlation was assessed using the intraclass correlation coefficient (ICC) and Bland-Altman plot. The predictive value of the rSO2 for mortality was calculated by ROC curve. Nineteen patients were included with an ICU mortality of 21.1%. The rSO2 values at baseline and at 24h were significantly higher in D than in BR muscle. Values obtained simultaneously in both limbs showed a strong correlation and adequate consistency: BR (r=0.95; p0.001) but a wide limit of agreement. Non-survivors had rSO2 values significantly lower than survivors at all times of the study. No patient with rSO2 >60% in BR died, and only 17.6% died with an rSO2 value >60% in D. Both muscles showed consistent discriminatory power for mortality. Both BR and D muscles were appropriate for measuring rSO2. Copyright © 2013 Elsevier España, S.L.U. and SEMICYUC. All rights reserved.

  11. Theoretical model for optical oximetry at the capillary level: exploring hemoglobin oxygen saturation through backscattering of single red blood cells

    Science.gov (United States)

    Liu, Rongrong; Spicer, Graham; Chen, Siyu; Zhang, Hao F.; Yi, Ji; Backman, Vadim

    2017-02-01

    Oxygen saturation (sO2) of red blood cells (RBCs) in capillaries can indirectly assess local tissue oxygenation and metabolic function. For example, the altered retinal oxygenation in diabetic retinopathy and local hypoxia during tumor development in cancer are reflected by abnormal sO2 of local capillary networks. However, it is far from clear whether accurate label-free optical oximetry (i.e., measuring hemoglobin sO2) is feasible from dispersed RBCs at the single capillary level. The sO2-dependent hemoglobin absorption contrast present in optical scattering signal is complicated by geometry-dependent scattering from RBCs. We present a numerical study of backscattering spectra from single RBCs based on the first-order Born approximation, considering practical factors: RBC orientations, size variation, and deformations. We show that the oscillatory spectral behavior of RBC geometries is smoothed by variations in cell size and orientation, resulting in clear sO2-dependent spectral contrast. In addition, this spectral contrast persists with different mean cellular hemoglobin content and different deformations of RBCs. This study shows for the first time the feasibility of, and provides a theoretical model for, label-free optical oximetry at the single capillary level using backscattering-based imaging modalities, challenging the popular view that such measurements are impossible at the single capillary level.

  12. Ultra-broadband nonlinear saturable absorption of high-yield MoS2 nanosheets

    Science.gov (United States)

    Wei, Rongfei; Zhang, Hang; Hu, Zhongliang; Qiao, Tian; He, Xin; Guo, Qiangbing; Tian, Xiangling; Chen, Zhi; Qiu, Jianrong

    2016-07-01

    High-yield MoS2 nanosheets with strong nonlinear optical (NLO) responses in a broad near-infrared range were synthesized by a facile hydrothermal method. The observation of saturable absorption, which was excited by the light with photon energy smaller than the gap energy of MoS2, can be attributed to the enhancement of the hybridization between the Mo d-orbital and S p-orbital by the oxygen incorporation into MoS2. High-yield MoS2 nanosheets with high modulation depth and large saturable intensity generated a stable, passively Q-switched fiber laser pulse at 1.56 μm. The high output power of 1.08 mW can be attained under a very low pump power of 30.87 mW. Compared to recently reported passively Q-switched fiber lasers utilizing exfoliated MoS2 nanosheets, the efficiency of the laser for our passive Q-switching operation is larger and reaches 3.50%. This research may extend the understanding on the NLO properties of MoS2 and indicate the feasibility of the high-yield MoS2 nanosheets to passively Q-switched fiber laser effectively at low pump strengths.

  13. Intelligent Approach for Analysis of Respiratory Signals and Oxygen Saturation in the Sleep Apnea/Hypopnea Syndrome

    Science.gov (United States)

    Moret-Bonillo, Vicente; Alvarez-Estévez, Diego; Fernández-Leal, Angel; Hernández-Pereira, Elena

    2014-01-01

    This work deals with the development of an intelligent approach for clinical decision making in the diagnosis of the Sleep Apnea/Hypopnea Syndrome, SAHS, from the analysis of respiratory signals and oxygen saturation in arterial blood, SaO2. In order to accomplish the task the proposed approach makes use of different artificial intelligence techniques and reasoning processes being able to deal with imprecise data. These reasoning processes are based on fuzzy logic and on temporal analysis of the information. The developed approach also takes into account the possibility of artifacts in the monitored signals. Detection and characterization of signal artifacts allows detection of false positives. Identification of relevant diagnostic patterns and temporal correlation of events is performed through the implementation of temporal constraints. PMID:25035712

  14. Simultaneous, noninvasive, in vivo, continuous monitoring of hematocrit, vascular volume, hemoglobin oxygen saturation, pulse rate and breathing rate in humans and other animal models using a single light source

    Science.gov (United States)

    Dent, Paul; Tun, Sai Han; Fillioe, Seth; Deng, Bin; Satalin, Josh; Nieman, Gary; Wilcox, Kailyn; Searles, Quinn; Narsipur, Sri; Peterson, Charles M.; Goodisman, Jerry; Mostrom, James; Steinmann, Richard; Chaiken, J.

    2018-02-01

    We previously reported a new algorithm "PV[O]H" for continuous, noninvasive, in vivo monitoring of hematocrit changes in blood and have since shown its utility for monitoring in humans during 1) hemodialysis, 2) orthostatic perturbations and 3) during blood loss and fluid replacement in a rat model. We now show that the algorithm is sensitive to changes in hemoglobin oxygen saturation. We document the phenomenology of the effect and explain the effect using new results obtained from humans and rat models. The oxygen sensitivity derives from the differential absorption of autofluorescence originating in the static tissues by oxy and deoxy hemoglobin. Using this approach we show how to perform simultaneous, noninvasive, in vivo, continuous monitoring of hematocrit, vascular volume, hemoglobin oxygen saturation, pulse rate and breathing rate in mammals using a single light source. We suspect that monitoring of changes in this suite of vital signs can be provided with improved time response, sensitivity and precision compared to existing methodologies. Initial results also offer a more detailed glimpse into the systemic oxygen transport in the circulatory system of humans.

  15. The Relationship between Oxygen Saturation and Color Alteration of a Compromised Skin Flap: Experimental Study on the Rabbit

    Directory of Open Access Journals (Sweden)

    Theddeus O. H. Prasetyono

    2013-09-01

    Full Text Available Background The aim of this study was to collect important data on the time of oxygensaturation change in relation to skin flap color alteration using non-invasive pulse oximetryto evaluate its ability to provide continuous monitoring of skin flap perfusion.Methods An experimental study on the monitoring of blood perfusion of 20 tube-islandgroin flaps of 10 male New Zealand rabbits was performed using pulse oximetry. The animalswere randomly assigned to one of two groups representing a blockage of either arterial orvenous blood flow. The oxygen saturation change and clinical color alteration were monitoredfrom the beginning of vessel clamping until the saturation became undetectable. The resultwas analyzed by the t-test using SSPS ver. 10.0.Results The mean times from the vessel clamping until the saturation became undetectablewere 20.19±2.13 seconds and 74.91±10.57 seconds for the artery and vein clamping groups,respectively. The mean time of the clinical alteration from the beginning of vein clampingwas 34.5±11.72 minutes, while the alteration in flaps with artery clamping could not bedetected until 2.5 hours after clamping.Conclusions The use of neonate-type reusable flex sensor-pulse oximetry is objective andeffective in early detection of arterial and vein blockage. It provides real-time data on vesselocclusion, which in turn will allow for early salvaging. The detection periods of both arterialocclusion and venous congestion are much earlier than the color alteration one may encounterclinically.

  16. Inspiratory Muscle Training and Arterial Blood Oxygen Saturation in Patients With Chronic Obstructive Pulmonary Disease

    Directory of Open Access Journals (Sweden)

    Bakhshandeh Bavarsad

    2015-01-01

    Full Text Available Background One of the problems of the patients with chronic obstructive pulmonary disease (COPD is the weakness of the respiratory muscles that causes oxygen desaturation at rest and activity and decreases exercise tolerance. Objectives This study aimed to investigate the effect of inspiratory muscle training on arterial oxygen saturation (SPO2. Patients and Methods Forty patients with mild to very severe COPD were recruited for this study, which is a randomized control trail. The patients were randomized to IMT (inspiratory muscle training and control group. Training was performed with Respivol (a kind of inspiratory muscle trainer for 8 weeks (15 min/d for 6 d/week. SPSS software version 16 was used to analyze the data by performing independent t test, paired t test, and Fisher exact test. Results Results showed that, after 8 weeks of inspiratory muscle training, there was a little increase (but not statistically significant improvement in SPO2 (from 92.6 ± 8.71 % to 95.13 ± 7.08 %, with P = 0.06, whereas it remained unchanged in the control group (from 96.0 ± 3.46 % to 96.4 ± 3.35 % with P = 0.51. No statistically significant difference was seen between the two groups (P > 0.05. Conclusions Although inspiratory muscles training can prevent desaturation, which is caused by activity, it fails to improve it.

  17. Aratos et le stoïcisme Aratus and Stoicism Arato e lo stoicismo

    Directory of Open Access Journals (Sweden)

    Christophe Cusset

    2011-07-01

    Full Text Available Dans cet article nous envisageons d'abord les points de rencontre possibles entre Aratos et le stoïcisme du point de vue de la biographie du poète avant de reprendre la lecture de l'ouverture des Phénomènes à la lumière de l'Hymne à Zeus de Cléanthe. Les rapports d’Aratos avec le stoïcisme se révèlent finalement être assez minces en ce qui concerne l’écriture du poète. Aratos est surtout stoïcien par l’intérêt que les Stoïciens ont porté à son œuvre qui se trouve avoir été composée dans un milieu assez fortement marqué par la philosophie du Portique.In this paper I consider first the possible points of tangent between Aratus and Stoicism as far as the biographical point of view is concerned, and secondly read the opening of the Phaenomena in the light of the Hymn to Zeus of Cleanthes again. Aratus’ links with Stoicism ultimately prove to be quite thin in the writing of the poet. Stoic Aratus is especially the creation of the interest that Stoics did manifest to his work, a work which was composed in an environment quite widely influenced by the philosophy of the Stoa.In questo articolo sono considerati in primo luogo i possibili punti di contatto tra Arato e lo stoicismo dal punto di vista della biografia del poeta prima di riprendere la lettura dell’inizio dei Fenomeni alla luce dell’Inno a Zeus di Cleante. I rapporti tra Arato e lo stoicismo si rivelano alquanto esili in ciò che concerne la scrittura del poeta. Arato è stoico principalmente per l’interesse che gli stoici hanno mostrato nei confronti della sua opera, che è stata composta in un milieu profondamente segnato dalla filosofia della Stoa.

  18. Corrosion Resistance of Steels and Armco-Fe in Lead Melt Saturated by Oxygen at 550 degree C

    International Nuclear Information System (INIS)

    Tsisar, V.P.; Fedirko, V.N.; Eliseeva, O.I.

    2007-01-01

    Corrosion resistance of stainless steels and Armco-Fe in static lead melt saturated by oxygen at 550 degree C for 2000 h was investigated. It was determined that double oxide layer was formed on the surface of investigated materials. Outer part of double oxide growths from the initial interface 'solid metal/liquid lead' towards the melt and consists of Fe 3 O 4 . Inner part of double oxide based on the matrix is composed of Fe 3 O 4 for Armco-Fe, Fe 1+x Cr 2-x O 4 for martensitic 0.2 C-13 Cr and ferritic-martensitic EP823 steels and Fe 1+x Cr 2- xO 4 +Ni for austenitic 18Cr-10Ni-1Ti. Lead did not penetrate into the matrix of tested materials and was detected only in the scale formed on austenitic steel

  19. Effects of salmeterol on sleeping oxygen saturation in chronic obstructive pulmonary disease.

    LENUS (Irish Health Repository)

    Ryan, Silke

    2012-02-01

    BACKGROUND: Sleep is associated with important adverse effects in patients with chronic obstructive pulmonary disease (COPD), such as disturbed sleep quality and gas exchange, including hypoxemia and hypercapnia. The effects of inhaled long-acting beta(2)-agonist therapy (LABA) on these disturbances are unclear. OBJECTIVES: The aim of the study was to assess the effect of inhaled salmeterol on nocturnal sleeping arterial oxygen saturation (SaO(2)) and sleep quality. METHODS: In a randomized, double-blind, placebo-controlled, crossover study of moderate\\/severe stable COPD patients, we compared the effects of 4 weeks of treatment with salmeterol 50 microg b.d. and matching placebo on sleeping SaO(2) and sleep quality. Overnight polysomnography (PSG) was performed at baseline, and after 4 and 8 weeks in addition to detailed pulmonary function testing. Of 15 patients included, 12 completed the trial (median age 69 years, forced expiratory volume in 1 s, FEV(1): 39%). RESULTS: Both mean SaO(2) [salmeterol vs. placebo: 92.9% (91.2, 94.7) vs. 91.0% (88.9, 94.8); p = 0.016] and the percentage of sleep spent below 90% of SaO(2) [1.8% (0.0, 10.8) vs. 25.6% (0.5, 53.5); p = 0.005] improved significantly with salmeterol. Sleep quality was similar with both salmeterol and placebo on PSG. Static lung volumes, particularly trapped gas volume, tended to improve with salmeterol. CONCLUSION: We conclude that inhaled LABA therapy improves sleeping SaO(2) without significant change in sleep quality.

  20. What is the best practice for benchmark regulation of electricity distribution? Comparison of DEA, SFA and StoNED methods

    International Nuclear Information System (INIS)

    Kuosmanen, Timo; Saastamoinen, Antti; Sipiläinen, Timo

    2013-01-01

    Electricity distribution is a natural local monopoly. In many countries, the regulators of this sector apply frontier methods such as data envelopment analysis (DEA) or stochastic frontier analysis (SFA) to estimate the efficient cost of operation. In Finland, a new StoNED method was adopted in 2012. This paper compares DEA, SFA and StoNED in the context of regulating electricity distribution. Using data from Finland, we compare the impacts of methodological choices on cost efficiency estimates and acceptable cost. While the efficiency estimates are highly correlated, the cost targets reveal major differences. In addition, we examine performance of the methods by Monte Carlo simulations. We calibrate the data generation process (DGP) to closely match the empirical data and the model specification of the regulator. We find that the StoNED estimator yields a root mean squared error (RMSE) of 4% with the sample size 100. Precision improves as the sample size increases. The DEA estimator yields an RMSE of approximately 10%, but performance deteriorates as the sample size increases. The SFA estimator has an RMSE of 144%. The poor performance of SFA is due to the wrong functional form and multicollinearity. - Highlights: • We compare DEA, SFA and StoNED methods in the context of regulation of electricity distribution. • Both empirical comparisons and Monte Carlo simulations are presented. • Choice of benchmarking method has a significant economic impact on the regulatory outcomes. • StoNED yields the most precise results in the Monte Carlo simulations. • Five lessons concerning heterogeneity, noise, frontier, simulations, and implementation

  1. Society of cardiovascular anesthesiologists: the effect of blood pressure regulation during aortic coarctation repair on brain, kidney, and muscle oxygen saturation measured by near-infrared spectroscopy: a randomized, clinical trial

    NARCIS (Netherlands)

    Moerman, Annelies; Bové, Thierry; François, Katrien; Jacobs, Stefan; Deblaere, Isabel; Wouters, Patrick; de Hert, Stefan

    2013-01-01

    In this study, we compared the effects of 3 frequently used arterial blood pressure-regulating agents on brain (rScO2), renal (SrO2), and muscle (SmO2) oxygen saturation, during aortic coarctation repair in children. Based on the reported adverse effect of sodium nitroprusside (SNP) on left-sided

  2. Serum albumin--a non-saturable carrier

    DEFF Research Database (Denmark)

    Brodersen, R; Honoré, B; Larsen, F G

    1984-01-01

    The shape of binding isotherms for sixteen ligands to human serum albumin showed no signs of approaching saturation at high ligand concentrations. It is suggested that ligand binding to serum albumin is essentially different from saturable binding of substrates to enzymes, of oxygen to haemoglobi...

  3. Simultaneous estimation of transcutaneous bilirubin, hemoglobin, and melanin based on diffuse reflectance spectroscopy

    Science.gov (United States)

    Nishidate, Izumi; Abdul, Wares MD.; Ohtsu, Mizuki; Nakano, Kazuya; Haneishi, Hideaki

    2018-02-01

    We propose a method to estimate transcutaneous bilirubin, hemoglobin, and melanin based on the diffuse reflectance spectroscopy. In the proposed method, the Monte Carlo simulation-based multiple regression analysis for an absorbance spectrum in the visible wavelength region (460-590 nm) is used to specify the concentrations of bilirubin (Cbil), oxygenated hemoglobin (Coh), deoxygenated hemoglobin (Cdh), and melanin (Cm). Using the absorbance spectrum calculated from the measured diffuse reflectance spectrum as a response variable and the extinction coefficients of bilirubin, oxygenated hemoglobin, deoxygenated hemoglobin, and melanin, as predictor variables, multiple regression analysis provides regression coefficients. Concentrations of bilirubin, oxygenated hemoglobin, deoxygenated hemoglobin, and melanin, are then determined from the regression coefficients using conversion vectors that are numerically deduced in advance by the Monte Carlo simulations for light transport in skin. Total hemoglobin concentration (Cth) and tissue oxygen saturation (StO2) are simply calculated from the oxygenated hemoglobin and deoxygenated hemoglobin. In vivo animal experiments with bile duct ligation in rats demonstrated that the estimated Cbil is increased after ligation of bile duct and reaches to around 20 mg/dl at 72 h after the onset of the ligation, which corresponds to the reference value of Cbil measured by a commercially available transcutaneous bilirubin meter. We also performed in vivo experiments with rats while varying the fraction of inspired oxygen (FiO2). Coh and Cdh decreased and increased, respectively, as FiO2 decreased. Consequently, StO2 was dramatically decreased. The results in this study indicate potential of the method for simultaneous evaluation of multiple chromophores in skin tissue.

  4. The effect of oxygen pressure on structure, electrical conductivity and oxygen permeability of Ba0.5Sr0.5Co0.8Fe0.2O3-δ thin films by pulsed laser deposition

    Directory of Open Access Journals (Sweden)

    S Daneshmandi

    2013-09-01

    Full Text Available  In this paper, Ba0.5Sr0.5Co0.8Fe0.2O3-δ (BSCF thin films were deposited on single crystal SrTiO3 (STO (100 by pulsed laser deposition (PLD technique at different pressures of oxygen. Crystal structure of bulk and thin film samples was studied by x-ray diffraction (XRD. The XRD results indicate that both bulk and thin film samples have cubic structures. AFM micrographs showed an increase in RMS roughness by oxygen pressure. The electrical resistance was measured at room temperature up to 600 and 800 °C in air using four probe method for bulk and thin films, respectively. A sharp drop in resistance was observed by increasing temperature up to 400 °C, that was explained with the small polaron hopping model. Polaron activation energy was calculated by Arrhenius relation. It was decreased over increasing oxygen pressure. The surface exchange coefficient (Kchem of the 300 mTorr sample was measured by electrical conductivity relaxation (ECR technique. The results suggested a linear relationship between Kchem and reciprocal of absolute temperature.

  5. Interleaved quantitative BOLD: Combining extravascular R2' - and intravascular R2-measurements for estimation of deoxygenated blood volume and hemoglobin oxygen saturation.

    Science.gov (United States)

    Lee, Hyunyeol; Englund, Erin K; Wehrli, Felix W

    2018-03-23

    Quantitative BOLD (qBOLD), a non-invasive MRI method for assessment of hemodynamic and metabolic properties of the brain in the baseline state, provides spatial maps of deoxygenated blood volume fraction (DBV) and hemoglobin oxygen saturation (HbO 2 ) by means of an analytical model for the temporal evolution of free-induction-decay signals in the extravascular compartment. However, mutual coupling between DBV and HbO 2 in the signal model results in considerable estimation uncertainty precluding achievement of a unique set of solutions. To address this problem, we developed an interleaved qBOLD method (iqBOLD) that combines extravascular R 2 ' and intravascular R 2 mapping techniques so as to obtain prior knowledge for the two unknown parameters. To achieve these goals, asymmetric spin echo and velocity-selective spin-labeling (VSSL) modules were interleaved in a single pulse sequence. Prior to VSSL, arterial blood and CSF signals were suppressed to produce reliable estimates for cerebral venous blood volume fraction (CBV v ) as well as venous blood R 2 (to yield HbO 2 ). Parameter maps derived from the VSSL module were employed to initialize DBV and HbO 2 in the qBOLD processing. Numerical simulations and in vivo experiments at 3 T were performed to evaluate the performance of iqBOLD in comparison to the parent qBOLD method. Data obtained in eight healthy subjects yielded plausible values averaging 60.1 ± 3.3% for HbO 2 and 3.1 ± 0.5 and 2.0 ± 0.4% for DBV in gray and white matter, respectively. Furthermore, the results show that prior estimates of CBV v and HbO 2 from the VSSL component enhance the solution stability in the qBOLD processing, and thus suggest the feasibility of iqBOLD as a promising alternative to the conventional technique for quantifying neurometabolic parameters. Copyright © 2018. Published by Elsevier Inc.

  6. Sulfated tin oxide (STO – Structural properties and application in catalysis: A review

    Directory of Open Access Journals (Sweden)

    Ravi Varala

    2016-07-01

    Full Text Available Catalysis is an important area of chemistry, with an extensive amount of work going on in this area of sciences, toward synthesis and evaluation of newer catalysts. There are many reports for different conversion reactions such as oxidation, reduction, coupling, alkylation, and acylation for which various catalysts have been used such as mixed metal oxides, metal nanoparticles, metal organic complexes and many others. Among the many catalysts reported, the one catalyst that caught our attention due to its exploitation for a plethora of organic conversions is the sulfated tin oxide (STO, which is due to the low cost, greater stability and high efficiency of the catalyst. In this review, we have attempted to compile data about the structural properties of STO, and its applications as catalysts in various organic synthesis are presented. The literature data up to 2014 were collected and considered for the review.

  7. System Li2O-MoO3 as a catalyst of oxygen (air) electrode

    International Nuclear Information System (INIS)

    Gavdzik, A.; Gajda, S.; Sofronkov, A.

    2000-01-01

    Potential of electrode on the basis of system Li x Mo 2-x O 6 (x 0.1-0.5) in alkaline solution saturated by oxygen was studied by the method of polarization curves recording. It is ascertained that the value of stationary potential characteristic of the electrode described under the conditions mentioned is determined by reversible reaction between oxygen and water molecules, resulting in formation of hydroxyl and hydrogen peroxide anions. Practicability of using the solid solutions on the basis of molybdenum oxide with additions of lithium oxide as a catalyst of oxygen (air) electrode in electrochemical current sources is demonstrated [ru

  8. Luminescence spectroscopic observation of singlet oxygen formation in extra virgin olive oil as affected by irradiation light wavelengths, 1,4-diazabicyclo[2.2.2]octane, irradiation time, and oxygen bubbling.

    Science.gov (United States)

    Jung, Mun Y; Choi, Dong S; Park, Ki H; Lee, Bosoon; Min, David B

    2011-01-01

    A spectrofluorometer equipped with a highly sensitive near-IR InGaAs detector was used for the direct visualization of singlet oxygen emission at 1268 nm in olive oil during light irradiation with various different wavelengths. The virgin olive oil in methylene chloride (20% w/v, oxygen saturated) was irradiated at the 301, 417, 454, 483, and 668 nm, then the emission at 1268 nm, singlet oxygen dimole decaying was observed. The result showed the highest production of (1)O(2) with light irradiation at 417 nm, and followed by at 668 nm in virgin olive oil, indicating that pheophytin a and chlorophyll a were the most responsible components for the production of singlet oxygen. The UV light irradiations at the wavelength of 200, 250, and 300 nm did not induce any detectable luminescence emission at 1268 nm, but 350 nm produced weak emission at 1269 nm. The quantity of (1)O(2) produced with excitation at 350 nm was about 1/6 of that of irradiation at 417 nm. Addition of an efficient (1)O(2) quencher, 1,4-diazabicyclo[2.2.2]octane, in virgin olive oil in methylene chloride greatly decreased the luminescence emission at 1268 nm, confirming the singlet oxygen production in olive oil. Singlet oxygen production was more efficient in oxygen-purged virgin olive oil than in oxygen non-purged olive oil. This represents first report on the direct observation of singlet oxygen formation in olive oil as well as in real-food system after visible light illumination. Practical Application: The present results show the positive evidence of the singlet oxygen involvement in rapid oxidative deterioration of virgin olive oil under visible light. This paper also shows the effects of different wavelength of light irradiation on the formation of singlet oxygen in olive oil. The present results would provide important information for the understanding of the mechanism involved in rapid oxidative quality deterioration of virgin olive oil under light illumination and for searching the

  9. Photoacoustic measurements of red blood cell oxygen saturation in blood bags in situ

    Science.gov (United States)

    Pinto, Ruben N.; Bagga, Karan; Douplik, Alexandre; Acker, Jason P.; Kolios, Michael C.

    2017-03-01

    Red blood cell (RBC) transfusion is a critical component of the health care services. RBCs are stored in blood bags in hypothermic temperatures for a maximum of 6 weeks post donation. During this in vitro storage period, RBCs have been documented to undergo changes in structure and function due to mechanical and biochemical stress. Currently, there are no assessment methods that monitor the quality of RBCs within blood bags stored for transfusion. Conventional assessment methods require the extraction of samples, consequently voiding the sterility of the blood bags and potentially rendering them unfit for transfusions. It is hypothesized that photoacoustic (PA) technology can provide a rapid and non-invasive indication of RBC quality. In this study, a novel PA setup was developed for the acquisition of oxygen saturation (SO2) of two blood bags in situ. These measurements were taken throughout the lifespan of the blood bags (42 days) and compared against the clinical gold standard method of the blood gas analyzer (BGA). SO2 values of the blood bags increased monotonically throughout the storage period. A strong correlation between PA SO2 and BGA SO2 was found, however, PA values were on average 3.5% lower. Both techniques found the bags to increase by an SO2 of approximately 20%, and measured very similar rates of SO2 change. Future work will be focused on determining the cause of discrepancy between SO2 values acquired from PA versus BGA, as well as establishing links between the measured SO2 increase and other changes in RBC in situ.

  10. Oxygen therapy reduces postoperative tachycardia

    DEFF Research Database (Denmark)

    Stausholm, K; Kehlet, H; Rosenberg, J

    1995-01-01

    Concomitant hypoxaemia and tachycardia in the postoperative period is unfavourable for the myocardium. Since hypoxaemia per se may be involved in the pathogenesis of postoperative tachycardia, we have studied the effect of oxygen therapy on tachycardia in 12 patients randomly allocated to blinded...... air or oxygen by facemask on the second or third day after major surgery. Inclusion criteria were arterial hypoxaemia (oxygen saturation 90 beat.min-1). Each patient responded similarly to oxygen therapy: an increase in arterial oxygen saturation and a decrease...... in heart rate (p oxygen has a positive effect on the cardiac oxygen delivery and demand balance....

  11. Poincaré analysis of an overnight arterial oxygen saturation signal applied to the diagnosis of sleep apnea hypopnea syndrome

    International Nuclear Information System (INIS)

    Morillo, Daniel S; Rojas, Juan L; Crespo, Luis F; León, Antonio; Gross, Nicole

    2009-01-01

    The analysis of oxygen desaturations is a basic variable in polysomnographic studies for the diagnosis of sleep apnea. Several algorithms operating in the time domain already exist for sleep apnea detection via pulse oximetry, but in a disadvantageous way—they achieve either a high sensitivity or a high specificity. The aim of this study was to assess whether an alternative analysis of arterial oxygen saturation (SaO 2 ) signals from overnight pulse oximetry could yield essential information on the diagnosis of sleep apnea hypopnea syndrome (SAHS). SaO 2 signals from 117 subjects were analyzed. The population was divided into a learning dataset (70 patients) and a test set (47 patients). The learning set was used for tuning thresholds among the applied Poincaré quantitative descriptors. Results showed that the presence of apnea events in SAHS patients caused an increase in the SD 1 Poincaré parameter. This conclusion was assessed prospectively using the test dataset. 90.9% sensitivity and 84.0% specificity were obtained in the test group. We conclude that Poincaré analysis could be useful in the study of SAHS, contributing to reduce the demand for polysomnographic studies in SAHS screening

  12. Improved Apnea-Hypopnea Index and Lowest Oxygen Saturation After Maxillomandibular Advancement With or Without Counterclockwise Rotation in Patients With Obstructive Sleep Apnea

    DEFF Research Database (Denmark)

    Knudsen, Torben B.; Laulund, Anne Sofie; Ingerslev, Janne

    2015-01-01

    - and postsurgical values of pharyngeal volume measured on computed tomogram or cone-beam computed tomogram and changes in Apnea-Hypopnea Index (AHI) and lowest oxygen saturation (LSAT) values after surgery. Datawere subjected to a meta-analysis based on odds ratios (OR) with 95% confidence intervals (CIs) and P...... between pharyngeal volume changes and surgical method used. Postoperative parameters included an AHI lower than 5 (OR = 14.9; 95% CI, 2.7-83.5; P = .002), an AHI lower than 20 (OR = 114.8; 95% CI, 23.5-561.1; P

  13. An applicable approach for extracting human heart rate and oxygen saturation during physical movements using a multi-wavelength illumination optoelectronic sensor system

    Science.gov (United States)

    Alharbi, Samah; Hu, Sijung; Mulvaney, David; Blanos, Panagiotis

    2018-02-01

    The ability to gather physiological parameters such as heart rate (HR) and oxygen saturation (SpO2%) during physical movement allows to continuously monitor personal health status without disrupt their normal daily activities. Photoplethysmography (PPG) based pulse oximetry and similar principle devices are unable to extract the HR and SpO2% reliably during physical movement due to interference in the signals that arise from motion artefacts (MAs). In this research, a flexible reflectance multi-wavelength optoelectronic patch sensor (OEPS) has been developed to overcome the susceptibility of conventional pulse oximetry readings to MAs. The OEPS incorporates light embittered diodes as illumination sources with four different wavelengths, e.g. green, orange, red, and infrared unlike the conventional pulse oximetry devices that normally measure the skin absorption of only two wavelengths (red and infrared). The additional green and orange wavelengths were found to be distinguish to the absorption of deoxyhemoglobin (RHb) and oxyhemoglobin (HbO2). The reliability of extracting physiological parameters from the green and orange wavelengths is due to absorbed near to the surface of the skin, thereby shortening the optical path and so effectively reducing the influence of physical movements. To compensate of MAs, a three-axis accelerometer was used as a reference with help of adaptive filter to reduce MAs. The experiments were performed using 15 healthy subjects aged 20 to 30. The primary results show that there are no significant difference of heart rate and oxygen saturation measurements between commercial devices and OEPS Green (r=0.992), Orange(r=0.984), Red(r=0.952) and IR(r=0.97) and SpO2% (r = 0.982, p = 0.894).

  14. New hybrid reflectance optical pulse oximetry sensor for lower oxygen saturation measurement and for broader clinical application

    Science.gov (United States)

    Nogawa, Masamichi; Ching, Chong Thong; Ida, Takeyuki; Itakura, Keiko; Takatani, Setsuo

    1997-06-01

    A new reflectance pulse oximeter sensor for lower arterial oxygen saturation (Sa)2) measurement has been designed and evaluated in animals prior to clinical trials. The new sensor incorporates ten light emitting diode chips for each wavelength of 730 and 880 nm mounted symmetrically and at the radial separation distance of 7 mm around a photodiode chip. The separation distance of 7 mm was chosen to maximize the ratio of the pulsatile to the average plethysmographic signal level at each wavelength. The 730 and 880 wavelength combination was determined to obtain a linear relationship between the reflectance ratio of the 730 and 880 nm wavelengths and Sa)2. In addition to these features of the sensor, the Fast Fourier Transform method was employed to compute the pulsatile and average signal level at each wavelength. The performance of the new reflectance pulse oximeter sensor was evaluated in dogs in comparison to the 665/910 nm sensor. As predicted by the theoretical simulation based on a 3D photon diffusion theory, the 730/880 nm sensor demonstrated an excellent linearity over the SaO2 range from 100 to 30 percent. For the SaO2 range between 100 and 70 percent, the 665/910 and 730/880 sensors showed the standard error of around 3.5 percent and 2.1 percent, respectively, in comparison to the blood samples. For the range between 70 and 30 percent, the standard error of the 730/880 nm sensor was only 2.7 percent, while that of the 665/910 nm sensor was 9.5 percent. The 730/880 sensor showed improved accuracy for a wide range of SaO2 particularly over the range between 70 and 30 percent. This new reflectance sensor can provide noninvasive measurement of SaO2 accurately over the wide saturation range from 100 to 30 percent.

  15. Non-invasive detection and quantification of brain microvascular deficits by near-infrared spectroscopy in a rat model of Vascular Cognitive Impairment

    Science.gov (United States)

    Hallacoglu, Bertan; Sassaroli, Angelo M.; Rosenberg, Irwin H.; Troen, Aron; Fantini, Sergio

    2011-02-01

    Structural abnormalities in brain microvasculature are commonly associated with Alzheimer's Disease and other dementias. However, the extent to which structural microvascular abnormalities cause functional impairments in brain circulation and thereby to cognitive impairment is unclear. Non-invasive, near-infrared spectroscopy (NIRS) methods can be used to determine the absolute hemoglobin concentration and saturation in brain tissue, from which additional parameters such as cerebral blood volume (a theoretical correlate of brain microvascular density) can be derived. Validating such NIRS parameters in animal models, and understanding their relationship to cognitive function is an important step in the ultimate application of these methods to humans. To this end we applied a non-invasive multidistance NIRS method to determine the absolute concentration and saturation of cerebral hemoglobin in rat, by separately measuring absorption and reduced scattering coefficients without relying on pre- or post-correction factors. We applied this method to study brain circulation in folate deficient rats, which express brain microvascular pathology1 and which we have shown to develop cognitive impairment.2 We found absolute brain hemoglobin concentration ([HbT]) and oxygen saturation (StO2) to be significantly lower in folate deficient rats (n=6) with respect to control rats (n=5) (for [HbT]: 73+/-10 μM vs. 95+/-14 μM for StO2: 55%+/-7% vs. 66% +/-4%), implicating microvascular pathology and diminished oxygen delivery as a mechanism of cognitive impairment. More generally, our study highlights how noninvasive, absolute NIRS measurements can provide unique insight into the pathophysiology of Vascular Cognitive Impairment. Applying this method to this and other rat models of cognitive impairment will help to validate physiologically meaningful NIRS parameters for the ultimate goal of studying cerebral microvascular disease and cognitive decline in humans.

  16. Intraoperative colonic pulse oximetry in left-sided colorectal surgery: can it predict anastomotic leak?

    Science.gov (United States)

    Salusjärvi, Johannes M; Carpelan-Holmström, Monika A; Louhimo, Johanna M; Kruuna, Olli; Scheinin, Tom M

    2018-03-01

    An anastomotic leak is a fairly common and a potentially lethal complication in colorectal surgery. Objective methods to assess the viability and blood circulation of the anastomosis could help in preventing leaks. Intraoperative pulse oximetry is a cheap, easy to use, fast, and readily available method to assess tissue viability. Our aim was to study whether intraoperative pulse oximetry can predict the development of an anastomotic leak. The study was a prospective single-arm study conducted between the years 2005 and 2011 in Helsinki University Hospital. Patient material consisted of 422 patients undergoing elective left-sided colorectal surgery. The patients were operated by one of the three surgeons. All of the operations were partial or total resections of the left side of the colon with a colorectal anastomosis. The intraoperative colonic oxygen saturation was measured with pulse oximetry from the colonic wall, and the values were analyzed with respect to post-operative complications. 2.3 times more operated anastomotic leaks occurred when the colonic StO 2 was ≤ 90% (11/129 vs 11/293). The mean colonic StO 2 was 91.1 in patients who developed an operated anastomotic leak and 93.0 in patients who did not. With logistic regression analysis, the risk of operated anastomotic leak was 4.2 times higher with StO 2 values ≤ 90%. Low intraoperative colonic StO 2 values are associated with the occurrence of anastomotic leak. Despite its handicaps, the method seems to be useful in assessing anastomotic viability.

  17. Optical noninvasive calculation of hemoglobin components concentrations and fractional oxygen saturation using a ring-scattering pulse oximeter

    Science.gov (United States)

    Abdallah, Omar; Stork, Wilhelm; Muller-Glaser, Klaus

    2004-06-01

    The deficiencies of the currently used pulse oximeter are discussed in diverse literature. A hazardous pitfalls of this method is that the pulse oximeter will not detect carboxyhemoglobin (COHb) and methemoglobin (metHb) concentrations. This leads to incorrect measurement of oxygen saturation by carbon monoxide poisoning and methemoglobinemia. Also the total hemoglobin concentration will not be considered and can only be measured in-vitro up to now. A second pitfall of the standard pulse oximetry is that it will not be able to show a result by low perfusion of tissues. This case is available inter alia when the patient is under shock or has a low blood pressure. The new non-invasive system we designed measures the actual (fractional) oxygen saturation and hemoglobin concentration. It will enable us also to measure COHb and metHb. The measurement can be applied at better perfused body central parts. Four or more light emitting diodes (LEDs) or laser diodes (LDs) and five photodiodes (PDs) are used. The reflected light signal detected by photodiodes is processed using a modified Lambert-Beer law (I=I0×e-α.d ). According to this law, when a non scattering probe is irradiated with light having the incident intensity I0, the intensity of transmitted light I decays exponentially with the absorption coefficient a of that probe and its thickness d. Modifications of this law have been performed following the theoretical developed models in literature, Monte Carlo simulation and experimental measurement.

  18. Interplay of tumor vascular oxygenation and tumor pO2 observed using near-infrared spectroscopy, an oxygen needle electrode, and 19F MR pO2 mapping.

    Science.gov (United States)

    Kim, Jae G; Zhao, Dawen; Song, Yulin; Constantinescu, Anca; Mason, Ralph P; Liu, Hanli

    2003-01-01

    This study investigates the correlation of tumor blood oxygenation and tumor pO(2) with respect to carbogen inhalation. After having refined and validated the algorithms for calculating hemoglobin concentrations, we used near-infrared spectroscopy (NIRS) to measure changes of oxygenated hemoglobin concentration (delta[HbO(2)]) and used an oxygen needle electrode and (19)F MRI for pO(2) measurements in tumors. The measurements were taken from Dunning prostate R3327 tumors implanted in rats, while the anesthetized rats breathed air or carbogen. The NIRS results from tumor measurements showed significant changes in tumor vascular oxygenation in response to carbogen inhalation, while the pO(2) electrode results showed an apparent heterogeneity for tumor pO(2) response to carbogen inhalation, which was also confirmed by (19)F MR pO(2) mapping. Furthermore, we developed algorithms to estimate hemoglobin oxygen saturation, sO(2), during gas intervention based on the measured values of delta[HbO(2)] and pO(2). The algorithms have been validated through a tissue-simulating phantom and used to estimate the values of sO(2) in the animal tumor measurement based on the NIRS and global mean pO(2) values. This study demonstrates that the NIRS technology can provide an efficient, real-time, noninvasive approach to monitoring tumor physiology and is complementary to other techniques, while it also demonstrates the need for an NIR imaging technique to study spatial heterogeneity of tumor vasculature under therapeutic interventions. Copyright 2003 Society of Photo-Optical Instrumentation Engineers

  19. Central venous oxygenation: when physiology explains apparent discrepancies.

    Science.gov (United States)

    Squara, Pierre

    2014-11-10

    Central venous oxygen saturation (ScvO2) >70% or mixed venous oxygen saturation (SvO2) >65% is recommended for both septic and non-septic patients. Although it is the task of experts to suggest clear and simple guidelines, there is a risk of reducing critical care to these simple recommendations. This article reviews the basic physiological and pathological features as well as the metrological issues that provide clear evidence that SvO2 and ScvO2 are adaptative variables with large inter-patient variability. This variability is exemplified in a modeled population of 1,000 standard ICU patients and in a real population of 100 patients including 15,860 measurements. In these populations, it can be seen how optimizing one to three of the four S(c)vO2 components homogenized the patients and yields a clear dependency with the fourth one. This explains the discordant results observed in large studies where cardiac output was increased up to predetermined S(c)vO2 thresholds following arterial oxygen hemoglobin saturation, total body oxygen consumption needs and hemoglobin optimization. Although a systematic S(c)vO2 goal-oriented protocol can be statistically profitable before ICU admission, appropriate intensive care mandates determination of the best compromise between S(c)vO2 and its four components, taking into account the specific constraints of each individual patient.

  20. Low oxygen saturation and severe anemia in compound heterozygous Hb Louisville [β42(CD1)Phe→Leu] and Hb La Desirade [β129(H7)Ala→Val].

    Science.gov (United States)

    Kamseng, Parin; Trakulsrichai, Satariya; Trachoo, Objoon; Yimniam, Walaiporn; Panthan, Bhakbhoom; Jittorntam, Paisan; Niparuck, Pimjai; Sanguanwit, Pitsucha; Wananukul, Winai; Jindadamrongwech, Sumalee

    2017-03-01

    To investigate the cause(s) of a Thai male proband presenting low oxygen saturation by pulse oximetry (SpO 2 ) and severe anemia. As Hb variant was suspected, Hb typing was determined by high-performance liquid chromatography and capillary electrophoresis, and subsequently Hb variant was identified by DNA sequencing. Complete blood counts were performed using automated blood cell counter and oxygen saturation was measured by pulse oximetry. Proband was compound heterozygous for Hb Louisville [β42(CD1)Phe→Leu] and Hb La Desirade [β129(H7)Ala→Val]. Of the proband's two sons, one was compound heterozygous for Hb Louisville and Hb E and the other for Hb La Desirade and Hb E. The former son had similar clinical features and laboratory findings with those of the proband while the latter showed had no abnormal clinical manifestations. This the first report of compound heterozygosity of Hb Louisville and Hb La Desirade in an individual of Southeast Asian ethnicity. Hb variant identification is crucial for genetic counseling and appropriate treatment in regions where hemoglobinopathies are common.

  1. Extra-cerebral oxygenation influence on near-infrared-spectroscopy-determined frontal lobe oxygenation in healthy volunteers

    DEFF Research Database (Denmark)

    Sørensen, Henrik; Rasmussen, Peter; Siebenmann, Christoph

    2015-01-01

    INTRODUCTION: Frontal lobe oxygenation (Sc O2 ) is assessed by spatially resolved near-infrared spectroscopy (SR-NIRS) although it seems influenced by extra-cerebral oxygenation. We aimed to quantify the impact of extra-cerebral oxygenation on two SR-NIRS derived Sc O2 . METHODS: Multiple...... regression analysis estimated the influence of extra-cerebral oxygenation as exemplified by skin oxygenation (Sskin O2 ) on Sc O2 in 21 healthy subjects exposed to whole-body exercise in hypoxia (Fi O2 = 12%; n = 10) and normoxia (n = 12), whole-body heating, hyperventilation (n = 21), administration...... of norepinephrine with and without petCO2 -correction (n = 15), phenylephrine and head-up tilt (n = 7). Sc O2 was assessed simultaneously by NIRO-200NX (Sniro O2 ) and INVOS-4100 (Sinvos O2 ). Arterial (Sa O2 ) and jugular bulb oxygen saturations (Sj O2 ) were obtained. RESULTS: The regression analysis indicated...

  2. Cryospectrophotometric determination of tumor intravascular oxyhemoglobin saturations: dependence on vascular geometry and tumor growth.

    Science.gov (United States)

    Fenton, B M; Rofstad, E K; Degner, F L; Sutherland, R M

    1988-12-21

    To delineate the complex relationships between overall tumor oxygenation and vascular configuration, intravascular oxyhemoglobin (HbO2) saturation distributions were measured with cryospectrophotometric techniques. Four factors related to vascular morphometry and tumor growth were evaluated: a) vessel diameter, b) distance of vessel from the tumor surface, c) tumor volume, and d) vascular density. To measure intertumor heterogeneity, two murine sarcomas (RIF-1 and KHT) and two human ovarian carcinoma xenografts (OWI and MLS) were utilized. In contrast to skeletal muscle, a preponderance of very low HbO2 saturations was observed for both large and small tumors of all lines. Saturations up to about 90% were also generally present, however, even in very large tumors. Variations in vascular configuration were predominantly tumor-line dependent rather than due to inherent characteristics of the host vasculature, and widely disparate HbO2 distributions were found for alternate lines implanted in identical host mice. Although peripheral saturations remained fairly constant with tumor growth, HbO2 values were markedly lower for vessels nearer the tumor center and further decreased with increasing tumor volume. HbO2 saturations did not change substantially with increasing vascular density (except for KHT tumors), although density did decrease with increasing distance from tumor surface. Combined effects of vessel diameter, tumor volume, and vessel location on HbO2 saturations were complex and varied markedly with both tumor line and vessel class. For specific classes, HbO2 distributions correlated closely with radiobiological hypoxic fractions, i.e., for tumor lines in which hypoxic fraction increased substantially with tumor volume, corresponding HbO2 values decreased, while for lines in which hypoxic fraction remained constant, HbO2 values also were unchanged. Although these trends may also be a function of differing oxygen consumption rates between tumor lines

  3. Investigating Functional Extension of Optical Coherence Tomography for Spectroscopic Analysis of Blood Oxygen Saturation

    Science.gov (United States)

    Chen, Siyu

    Over the past two decades, optical coherence tomography (OCT) has been successfully applied to various fields of biomedical researching and clinical studies, including cardiology, urology, dermatology, dentistry, oncology, and most successfully, ophthalmology. This dissertation seeks to extend the current OCT practice, which is still largely morphology-based, into a new dimension, functional analysis of metabolic activities in vivo. More specifically, the investigation is focused on retrieving blood oxygen saturation (sO2) using intrinsic hemoglobin optical absorption contrast. Most mammalian cells rely on aerobic respiration to support cellular function, which means they consume oxygen to create adenosine triphosphate (ATP). Metabolic rate of oxygen (MRO2), a key hemodynamic parameter, characterizes how much oxygen is consumed during a given period of time, reflecting the metabolic activity of the target tissue. For example, retinal neurons are highly active and almost entirely rely on the moment-to-moment oxygen supply from retinal circulations. Thus, variation in MRO2 reveals the instantaneous activity of these neurons, shedding light on the physiological and pathophysiological change of cellular functions. Eventually, measuring MRO2 can potentially provide a biomarker for early-stage disease diagnosis, and serve as one benchmark for evaluating effectiveness of medical intervention during disease management. Essential in calculating MRO2, blood sO2 measurements using spectroscopic OCT analysis has been attempted as early as 2003. OCT is intrinsically sensitive to the blood optical absorption spectrum due to its wide-band illumination and detection scheme relying on back-scattered photon. However, accurate retrieval of blood sO2 using conventional near infrared (NIR) OCT systems in vivo has remained challenging. It was not until the development of OCT systems using visible light illumination (vis-OCT) when accurate measurement of blood sO2 was reported in live

  4. Lactate, endothelin, and central venous oxygen saturation as predictors of mortality in patients with Tetralogy of Fallot

    Directory of Open Access Journals (Sweden)

    Poonam Malhotra Kapoor

    2016-01-01

    Full Text Available Background: Lactate and central venous oxygen saturation (ScVO2 are well known biomarkers for adequacy of tissue oxygenation. Endothelin, an inflammatory marker has been associated with patient′s nutritional status and degree of cyanosis. The aim of this study was to explore the hypothesis that lactate, ScVO2 and endothelin before induction may be predictive of mortality in pediatric cardiac surgery. Methods: We conducted a prospective observational study of 150 pediatric (6 months to 12 years patients who were posted for intracardiac repair for tetralogy of fallot and measured lactate, ScVO2 and endothelin before induction (T1, 20 minutes after protamine administration (T2 and 24 hours after admission to ICU (T3. Results: Preinduction lactate and endothelin levels were found to predict mortality in patients of tetralogy of fallot with an odds ratio of 6.020 (95% CI 2.111-17.168 and 1.292(95% CI 1.091-1.531 respectively. In the ROC curve analysis for lactate at T1, the AUC was 0.713 (95% CI 0.526-0.899 P = 0.019. At the cutoff value of 1.750mmol/lt, the sensitivity and specificity for the prediction of mortality was 63.6% and 65.5%, respectively. For endothelin at T1, the AUC was 0.699 (95% CI 0.516-0.883, P = 0.028 and the cutoff value was ≤2.50 (sensitivity, 63.6%; specificity, 58.3 %. ScVO2 (odds ratio 0.85 at all three time intervals, suggested that improving ScVO2 can lead to 15% reduction in mortality. Conclusions: Lactate, ScVO2 and endothelin all showed association with mortality with lactate having the maximum prediction. Lactate was found to be an independent, reliable and cost-effective measure of prediction of mortality in patients with tetralogy of fallot.

  5. Soil aquifer treatment of artificial wastewater under saturated conditions

    KAUST Repository

    Essandoh, H. M K; Tizaoui, Chedly; Mohamed, Mostafa H A; Amy, Gary L.; Brdjanovic, Damir

    2011-01-01

    A 2000 mm long saturated laboratory soil column was used to simulate soil aquifer treatment under saturated conditions to assess the removal of chemical and biochemical oxygen demand (COD and BOD), dissolved organic carbon (DOC), nitrogen

  6. Association of low non-invasive near-infrared spectroscopic measurements during initial trauma resuscitation with future development of multiple organ dysfunction.

    Science.gov (United States)

    Nicks, Bret A; Campons, Kevin M; Bozeman, William P

    2015-01-01

    Near-infrared spectroscopy (NIRS) non-invasively monitors muscle tissue oxygen saturation (StO2). It may provide a continuous noninvasive measurement to identify occult hypoperfusion, guide resuscitation, and predict the development of multiple organ dysfunction (MOD) after severe trauma. We evaluated the correlation between initial StO2 and the development of MOD in multi-trauma patients. Patients presenting to our urban, academic, Level I Trauma Center/Emergency Department and meeting standardized trauma-team activation criteria were enrolled in this prospective trial. NIRS monitoring was initiated immediately on arrival with collection of StO2 at the thenar eminence and continued up to 24 hours for those admitted to the Trauma Intensive Care Unit (TICU). Standardized resuscitation laboratory measures and clinical evaluation tools were collected. The primary outcome was the association between initial StO2 and the development of MOD within the first 24 hours based on a MOD score of 6 or greater. Descriptive statistical analyses were performed; numeric means, multivariate regression and rank sum comparisons were utilized. Clinicians were blinded from the StO2 values. Over a 14 month period, 78 patients were enrolled. Mean age was 40.9 years (SD 18.2), 84.4% were male, 76.9% had a blunt trauma mechanism and mean injury severity score (ISS) was 18.5 (SD 12.9). Of the 78 patients, 26 (33.3%) developed MOD within the first 24 hours. The MOD patients had mean initial StO2 values of 53.3 (SD 10.3), significantly lower than those of non-MOD patients 61.1 (SD 10.0); P=0.002. The mean ISS among MOD patients was 29.9 (SD 11.5), significantly higher than that of non-MODS patients, 12.1 (SD 9.1) (P<0.0001). The mean shock index (SI) among MOD patients was 0.92 (SD 0.28), also significantly higher than that of non-MODS patients, 0.73 (SD 0.19) (P=0.0007). Lactate values were not significantly different between groups. Non-invasive, continuous StO2 near-infrared spectroscopy

  7. Approach to Exchange Bias Effect in La2/3Ca1/3MnO3/BiFeO3 and BiFeO3/ La2/3Ca1/3MnO3 Bilayers

    Science.gov (United States)

    Dominguez, Claribel; Ordonez, John; Diez, Sandra; Gomez, Maria; Guénon, Stefan; Schuller, Ivan

    2013-03-01

    We have grown bilayers of ferromagnetic La2/3Ca1/3MnO3 (LCMO) and multiferroic BiFeO3 (BFO) on (100) SrTiO3 (STO) substrates, by DC- and magnetron RF -sputtering technique, respectively, at high-oxygen pressures. We maintain constant the thickness of the layers (tBFO=72nm; tLCMO=80nm). Temperature dependence of the resistivity indicates that the MI-transition temperature of the manganite in the BFO/LCMO/STO is affected by the presence of the BFO layer in comparison with TMI for the single LCMO layer. Furthermore, temperature dependence of magnetization shows that the BFO/LCMO/STO bilayer has higher Curie temperature than that for LCMO/BFO/STO, indicating a strong structural dependence of the LCMO layer with magnetic response. The dependence of the magnetic moment with magnetic field after field cooling gives indication of the existence of Exchange Bias effect in the LCMO/BFO/STO bilayer. Isothermal loops also display dependence of the Exchange Bias magnitude with field cooling. This work has been supported by UNIVALLE Research Project CI 7864, and ``El Patrimonio Autónomo Fondo Nacional de Financiamiento para CT&I FJC,'' Contract RC - No. 275-2011, COLCIENCIAS-CENM, Colombia

  8. Barley seed radiosensitivity following post-hydration in oxygen-, nitrogen- and nitrous oxide-saturated water, 1

    International Nuclear Information System (INIS)

    Singh, S.P.; Kesavan, P.C.

    1990-01-01

    Dry (∼3.5 and 4.0 per cent moisture content) barley seeds were exposed to 350 Gy of 60 Co-γ-rays in vacuo and post-hydrated at 4degC for 8 h in O 2 -, N 2 -, or N 2 O-saturated water. The effect of caffeine and t-butyl alcohol (t-BuOH) dissolved in the post-hydration medium on the magnitude of damage developing under these three different gaseous circumstances was studied. The post-irradiation damage and its modification by caffeine and t-BuOH was assessed in terms of 8-day-old seedling injury, peroxidase activity and total peroxides in the 8-day-old seedlings. Post-irradiation O 2 -saturated hydration caused maximal 8-day-old seedling injury, and increased peroxidase activity with concomitant reduction in total peroxides. Both caffeine and t-BuOH afforded significant radioprotection against post-irradiation O 2 -dependent damage. Post-irradiation N 2 O-saturated hydration was even more significantly radioprotective than the N 2 -saturated post-hydration. Under these circumstances, t-BuOH exerted no effect whatsoever on the N 2 - and N 2 O-mediated post-irradiation damage. Caffeine, on the other hand, significantly potentiated these two components of damage. A brief consideration of the physicochemical events which possibly account for the observed effects is presented. (author)

  9. Determination of the PO2 temperature blood factor from oxygen dissociation curves.

    Science.gov (United States)

    Hérigault, R A; Soulard, C D; Teisseire, B P; Laurent, D N

    1983-01-01

    The variation with saturation of the temperature coefficient of PO2 in human blood (delta log PO2/delta T) was determined by continuous recording of the oxygen dissociation curve (ODC), at 37 degrees C and 25 degrees C, on the same blood samples. PCO2 and pH were held constant through an ODC run, and PCO2 was reduced at 25 degrees C to the value measured by anaerobic cooling of the same sample. delta log PO2/delta T was calculated from isosaturation points on the 37 and 25 degrees C curves. The temperature coefficient was also computed as an independent check on this method by determination of the effects of temperature (25, 30, 37 and 40 degrees C) on hemoglobin ligand interaction: fixed acid Bohr effect (delta log PO2/delta pH), carbamino-formation (delta log PO2/delta log PCO2) and hemoglobin oxygen affinity. The values of delta log PO2/delta T ratio obtained from the two different approaches were found to be in good agreement. The coefficient decreased when [H+] concentration was increased. A linear relationship between the Bohr factor and the temperature was found: delta log PO2/delta pH = 0.00267 T-0.520 (r = 0.85; n = 40) At 25 degrees C, the carbamino-formation was one order of magnitude lower than at 37 degrees C. Acid-base state and saturation value appeared to be major determinant factors for the temperature correction coefficient to be applied to blood PO2 values measured at standard (37 degrees C) temperature.

  10. Vagal activity and oxygen saturation response to hypoxia: Effects of aerobic fitness and rating of hypoxia tolerance

    Directory of Open Access Journals (Sweden)

    Tomáš Macoun

    2017-10-01

    Full Text Available Background: A reduction in the inspired oxygen fraction (FiO2 induces a decline in arterial oxygen saturation (SpO2 and changes of heart rate variability (HRV. It has been shown that SpO2 and HRV responses to similar levels of acute normobaric hypoxia are inter-individual variable. Variable response may be influenced by normoxia reached maximal oxygen uptake (VO2max value. Objective: The primary aim was to assess HRV and the SpO2 response to hypoxia, and examine the association with normoxic VO2max. Methods: Supine HRV and SpO2 were monitored during normobaric hypoxia (FiO2 = 9.6% for 10 minutes in 28 subjects, aged 23.7 ± 1.7 years. HRV was evaluated by using both spectral and time domain HRV analysis. Low frequency (LF, 0.05-0.15 Hz and high frequency (HF, 0.15-0.50 Hz power together with square root of the mean of the squares of the successive differences (rMSSD were calculated and transformed by natural logarithm (Ln. Based on the SpO2 in hypoxia, subjects were divided into Resistant (RG, SpO2 ≥ 70.9%, n = 14 and Sensitive (SG, SpO2 < 70.9%, n = 14 groups. Perceived hypoxia tolerance was self-scored on a 4-level scale. Results: VO2max was higher in SG (62.4 ± 7.2 ml ⋅ kg-1 ⋅ min-1 compared with RG (55.5 ± 7.1 ml ⋅ kg-1 ⋅ min-1, p = .017, d = 0.97. A significant relationship (r = -.45, p = .017 between hypoxic-normoxic difference in SpO2 and normoxic VO2max level was found. Vagal activity (Ln rMSSD was significantly decreased (SG: p < .001, d = 2.64; RG: p < .001, d = 1.22, while sympathetic activity (Ln LF/HF was relatively increased (p < .001, d = -1.40 in only the SG during hypoxia. Conclusions: Results show that subjects with a higher aerobic capacity exhibited a greater decline in SpO2, accompanied by greater autonomic cardiac disturbances during hypoxia. The SpO2 reduction was associated with perceived hypoxia comfort/discomfort. The hypoxia

  11. Diffuse Optical Characterization of the Healthy Human Thyroid Tissue and Two Pathological Case Studies.

    Directory of Open Access Journals (Sweden)

    Claus Lindner

    Full Text Available The in vivo optical and hemodynamic properties of the healthy (n = 22 and pathological (n = 2 human thyroid tissue were measured non-invasively using a custom time-resolved spectroscopy (TRS and diffuse correlation spectroscopy (DCS system. Medical ultrasound was used to guide the placement of the hand-held hybrid optical probe. TRS measured the absorption and reduced scattering coefficients (μa, μs' at three wavelengths (690, 785 and 830 nm to derive total hemoglobin concentration (THC and oxygen saturation (StO2. DCS measured the microvascular blood flow index (BFI. Their dependencies on physiological and clinical parameters and positions along the thyroid were investigated and compared to the surrounding sternocleidomastoid muscle. The THC in the thyroid ranged from 131.9 μM to 144.8 μM, showing a 25-44% increase compared to the surrounding sternocleidomastoid muscle tissue. The blood flow was significantly higher in the thyroid (BFIthyroid = 16.0 × 10-9 cm2/s compared to the muscle (BFImuscle = 7.8 × 10-9 cm2/s, while StO2 showed a small (StO2, muscle = 63.8% to StO2, thyroid = 68.4%, yet significant difference. Two case studies with thyroid nodules underwent the same measurement protocol prior to thyroidectomy. Their THC and BFI reached values around 226.5 μM and 62.8 × 10-9 cm2/s respectively showing a clear contrast to the nodule-free thyroid tissue as well as the general population. The initial characterization of the healthy and pathologic human thyroid tissue lays the ground work for the future investigation on the use of diffuse optics in thyroid cancer screening.

  12. Changes in Oxygen Partial Pressure in the Vitreous Body and Arterial Blood of Rabbits Depending on Oxygen Concentration in Inspired Mixture.

    Science.gov (United States)

    Amkhanitskaya, L I; Nikolaeva, G V; Sokolova, N A

    2015-07-01

    We demonstrated that the vitreous body of one-month-old rabbits becomes a "reservoir" for storage and accumulation of oxygen after exposure to additional oxygenation of the organism (O2 concentrations in inspired gas mixture were 40, 60, 85, and 99%). The higher was O2 concentration in inspired mixture, the higher was oxygen saturation of the blood and vitreous body. O2 concentration of 40% was relatively safe for eye tissues. O2 concentration >60% induced oxygen accumulation in the vitreous body, which can be a provoking factor for the development of oxygen-induced pathologies.

  13. Development of theoretical oxygen saturation calibration curve based on optical density ratio and optical simulation approach

    Science.gov (United States)

    Jumadi, Nur Anida; Beng, Gan Kok; Ali, Mohd Alauddin Mohd; Zahedi, Edmond; Morsin, Marlia

    2017-09-01

    The implementation of surface-based Monte Carlo simulation technique for oxygen saturation (SaO2) calibration curve estimation is demonstrated in this paper. Generally, the calibration curve is estimated either from the empirical study using animals as the subject of experiment or is derived from mathematical equations. However, the determination of calibration curve using animal is time consuming and requires expertise to conduct the experiment. Alternatively, an optical simulation technique has been used widely in the biomedical optics field due to its capability to exhibit the real tissue behavior. The mathematical relationship between optical density (OD) and optical density ratios (ODR) associated with SaO2 during systole and diastole is used as the basis of obtaining the theoretical calibration curve. The optical properties correspond to systolic and diastolic behaviors were applied to the tissue model to mimic the optical properties of the tissues. Based on the absorbed ray flux at detectors, the OD and ODR were successfully calculated. The simulation results of optical density ratio occurred at every 20 % interval of SaO2 is presented with maximum error of 2.17 % when comparing it with previous numerical simulation technique (MC model). The findings reveal the potential of the proposed method to be used for extended calibration curve study using other wavelength pair.

  14. EFFECTIVENESS OF AUTOGENIC DRAINAGE VERSUS POSTURAL DRAINAGE ON OXYGEN SATURATION IN PATIENTS WITH CHRONIC BRONCHITIS WITH 15 MINUTES POST THERAPY

    OpenAIRE

    V. Kiran; Dr. Bhimasen .S; E. Mastanaiah; A. Thiruppathi

    2014-01-01

    Background: Patients with COPD will have more amount of secretions. To clear the secretions by using of different bronchial hygiene techniques like postural drainage and autogenic drainage technique, manual hyperventilation technique ,active cycle breathing technique .Hence in this study to compare the short-term effects of postural drainage with clapping (PD) and autogenic drainage (AD) on level of oxygen saturation in blood, and amount of sputum recovery. Methodology: The study was done ...

  15. Gaseous saturable absorbers for the Helios CO2 laser system

    International Nuclear Information System (INIS)

    Haglund, R.F. Jr.; Nowak, A.V.; Czuchlewski, S.J.

    1981-01-01

    Saturable absorbers are widely used to suppress parasitic oscillations in large-aperture, high-power CO 2 fusion-laser systems. We report experimental results on SF 6 -based gaseous saturable absorbers used for parasitic suppression in the eight-beam, 10 kJ Helios fusion-laser system. The gas mix effectively quenches self-lasing in the 9 and 10 μm branches of the CO 2 laser spectrum while simultaneously allowing high transmission of subnanosecond multiwavelength pulses for target-irradiation experiments. The gas isolator now in use consists of SF 6 and the additional fluorocarbons: 1, 1-difluoroethane (FC-152a); dichlorodifluoromethane (FC-12); chloropentafluoroethane (FC-115); 1,1-dichloro 2,2-difluoroethylene (FC-1112a); chlorotrifluoroethylene (FC-1113); and perfluorocyclobutane (FC-C318). The saturation of the mix was studied as a function of incident fluence, pressure, cell length, and incident wavelength. Experimental results are presented on the saturation properties of pure SF 6 and FC-152a and compared with the saturation behavior of CO 2 at 400 0 C

  16. From StoCharts to MoDeST: a comparative reliability analysis of train radio communications

    NARCIS (Netherlands)

    Hermanns, H.; Jansen, D.N.; Usenko, Y.S.

    StoCharts have been proposed as a UML statechart extension for performance and dependability evaluation, and have been applied in the context of train radio reliability assessment to show the principal tractability of realistic cases with this approach. In this paper, we extend on this bare

  17. Relaxation of functions of STO-3G and 6-31G* basis sets in the series of isoelectronic to LiF molecule

    International Nuclear Information System (INIS)

    Ermakov, A.I.; Belousov, V.V.

    2007-01-01

    Relaxation effect of functions of the basis sets (BS) STO-3G and 6-31G* on their equilibration in the series of isoelectron molecules: LiF, BeO, BN and C 2 is considered. Values of parameters (exponential factor of basis functions, orbital exponents of Gauss primitives and coefficients of their grouping) of basis functions in molecules are discovered using the criterion of minimum of energy by the unlimited Hartree-Fock method calculations (UHF) with the help of direct optimization of parameters: the simplex-method and Rosenbrock method. Certain schemes of optimization differing by the amount of varying parameters have been done. Interaction of basis functions parameters of concerned sets through medium values of the Gauss exponents is established. Effects of relaxation on the change of full energy and relative errors of the calculations of interatomic distances, normal oscillations frequencies, dissociation energy and other properties of molecules are considered. Change of full energy during the relaxation of basis functions (RBF) STO-3G and 6-31G* amounts 1100 and 80 kJ/mol correspondingly, and it is in need of the account during estimation of energetic characteristics, especially for systems with high-polar chemical bonds. The relaxation BS STO-3G practically in all considered cases improves description of molecular properties, whereas the relaxation BS 6-31G* lightly effects on its equilibration [ru

  18. LOW OXYGENATION STATUS INCREASES NAUSEA-VOMITING INCIDENCE IN HEMODIALYSIS PATIENTS

    Directory of Open Access Journals (Sweden)

    Cornelia DY Nekada

    2017-08-01

    Full Text Available Background and Objective: Data from Indonesia Basic Health Research (2013 states that the chronic renal failure in Indonesia is increasing, especially in Yogyakarta with the prevalence of chronic renal failure of 0,3%. If the patients of chronic renal failure are in End Stage Renal Disease (ESRD, the kidney needs replacement therapy to help its function. This therapy is called Continuous Renal Replacement Therapy (CRRT or Hemodialysis (HD. Hemodialysis therapy may influence to the imbalance of oxyhemoglobin in the blood. Patients undergoing hemodialysis may experience intradialytic nausea and vomiting. The objective of this study is to identify whether there is a relationship between pre-dialysis oxygenation status through oxygen saturation (SpO2 and respiratory rate (RR examination and the intradialytic nausea-vomiting occurrence. Method: This research is a comparative research with analytical cross sectional design. This research was conducted in hemodialysis room in Public Hospital of Panembahan Senopati Bantul. The subject of the research was taken using total sampling, by paying attention to research ethics. The total research subjects are 183 respondents. The researchers measured the oxygen saturation and patients’ respiratory rate and examined the intradialytic nausea and vomiting complaints. Result: The analysis result of Fisher’s exact in this research shows p value of 0,000 both in bivariate analysis of oxygen saturation to the nausea and vomiting occurrence and in bivariate analysis of the respiratory rate to the nausea and vomiting occurrence. The multivariate analysis employing regression logistic shows that the OR of oxygen saturation is 73,57, this means that the measurement of the abnormal oxygen saturation has the chance of seventy three times more to the nausea and vomiting occurrence, if compared to the patients with normal oxygen saturation. Conclusion and Suggestion: Intradialytic nausea and vomiting is one of the causes

  19. Stabilization of stoichiometric LaTiO{sub 3} thin films grown by pulsed laser deposition

    Energy Technology Data Exchange (ETDEWEB)

    Schmitt, Matthias; Scheiderer, Philipp; Goessmann, Alex; Sing, Michael; Claessen, Ralph [Universitaet Wuerzburg, Physikalisches Institut and Roentgen Center for Complex Material Systems (RCCM), 97074 Wuerzburg (Germany)

    2016-07-01

    Like in the famous oxide heterostructure LaAlO{sub 3}/SrTiO{sub 3} (LAO/STO) a two dimensional electron system is found at the interface between the strongly correlated Mott insulator LaTi{sup 3+}O{sub 3} and the band insulator STO. In contrast to LAO, the stabilization of LaTi{sup 3+}O{sub 3} requires strong reducing growth conditions since the thermodynamically stable bulk phase is the oxygen-rich La{sub 2}Ti{sup 4+}{sub 2}O{sub 7}. Therefore, we have systematically studied the impact of oxidizing and reducing background atmospheres and the influence of the substrate on LaTi{sup 3+}O{sub 3} thin film growth by pulsed laser deposition. In situ x-ray photoelectron spectroscopy of the films prepared on STO exhibit overoxidation probably due to oxygen out-diffusion from the STO substrate, which is reduced for growth on DyScO{sub 3} due to the lower oxygen mobility. In addition, we found that a LAO capping layer of a few unit cells thickness acting like a diffusion barrier for oxygen prevents the LTO film from overoxidation during storage in air.

  20. Impurities of oxygen in silicon

    International Nuclear Information System (INIS)

    Gomes, V.M.S.

    1985-01-01

    The electronic structure of oxygen complex defects in silicon, using molecular cluster model with saturation by watson sphere into the formalism of Xα multiple scattering method is studied. A systematic study of the simulation of perfect silicon crystal and an analysis of the increasing of atom number in the clusters are done to choose the suitable cluster for the calculations. The divacancy in three charge states (Si:V 2 + , Si:V 2 0 , Si:V 2 - ), of the oxygen pair (Si:O 2 ) and the oxygen-vacancy pair (Si:O.V) neighbours in the silicon lattice, is studied. Distortions for the symmetry were included in the Si:V 2 + and Si:O 2 systems. The behavior of defect levels related to the cluster size of Si:V 2 0 and Si:O 2 systems, the insulated oxygen impurity of silicon in interstitial position (Si:O i ), and the complexes involving four oxygen atoms are analysed. (M.C.K.) [pt

  1. Capillary-oxygenation-level-dependent near-infrared spectrometry in frontal lobe of humans

    NARCIS (Netherlands)

    Rasmussen, Peter; Dawson, Ellen A.; Nybo, Lars; van Lieshout, Johannes J.; Secher, Niels H.; Gjedde, Albert

    2007-01-01

    Brain function requires oxygen and maintenance of brain capillary oxygenation is important. We evaluated how faithfully frontal lobe near-infrared spectroscopy (NIRS) follows haemoglobin saturation (SCap) and how calculated mitochondrial oxygen tension (PMitoO2) influences motor performance. Twelve

  2. Oxygen diffusion through soil covers on sulphidic mine tailings

    International Nuclear Information System (INIS)

    Yanful, E.K.

    1993-01-01

    Engineered soil covers are being evaluated under Canada's Mine Environment Neutral Drainage (MEND) program for their effectiveness in preventing and controlling acid generation in sulfidic mill tailings. A critical parameter for predicting the performance of these covers is the diffusion coefficient of gaseous oxygen in the cover materials. Laboratory experiments conducted to determine the effective diffusion coefficient of a candidate cover material, a glacial till from an active mine site, are described. The diffusion coefficient is determined by fitting a semianalytic solution of the one-dimensional, transient diffusion equation to experimental gaseous oxygen concentration versus time graphs. Effective diffusion coefficients determined at high water saturations (85%--95%) were of the order of 8 x 10 -8 m 2 /s. The diffusion coefficients decreased with increase in water saturation as a result of the low diffusivity of gaseous oxygen in water relative to that in air and the low solubility of oxygen in water. Placement of soil covers in high saturation conditions would ensure that the flux of oxygen into tailings underneath such covers is low, resulting in low acid flux. This is confirmed by combined laboratory, field, and modeling studies

  3. Single-cell measurement of red blood cell oxygen affinity.

    Science.gov (United States)

    Di Caprio, Giuseppe; Stokes, Chris; Higgins, John M; Schonbrun, Ethan

    2015-08-11

    Oxygen is transported throughout the body by hemoglobin (Hb) in red blood cells (RBCs). Although the oxygen affinity of blood is well-understood and routinely assessed in patients by pulse oximetry, variability at the single-cell level has not been previously measured. In contrast, single-cell measurements of RBC volume and Hb concentration are taken millions of times per day by clinical hematology analyzers, and they are important factors in determining the health of the hematologic system. To better understand the variability and determinants of oxygen affinity on a cellular level, we have developed a system that quantifies the oxygen saturation, cell volume, and Hb concentration for individual RBCs in high throughput. We find that the variability in single-cell saturation peaks at an oxygen partial pressure of 2.9%, which corresponds to the maximum slope of the oxygen-Hb dissociation curve. In addition, single-cell oxygen affinity is positively correlated with Hb concentration but independent of osmolarity, which suggests variation in the Hb to 2,3-diphosphoglycerate (2-3 DPG) ratio on a cellular level. By quantifying the functional behavior of a cellular population, our system adds a dimension to blood cell analysis and other measurements of single-cell variability.

  4. Calculation of heat exchangers with saturated and underheated superfluid helium (He-2)

    International Nuclear Information System (INIS)

    Belyakov, V.P.; Shaposhnikov, V.A.; Budrik, V.V.; Volkova, N.M.

    1986-01-01

    Calculation technique for heat exchangers with saturated and underheated He-2 under conditions of natural inner convection and forced convection is delivered. The following variants of heat exchangers are considered: inside the bath with saturated He-2 a tube is placed along which subcooled He-2 flow moves with a constant rate; inside the bath with subcooled He-2 a tube is placed both ends of which are in the bath with saturated He-2; inside the bath with saturated He-2 a tube is placed both ends of which are in the bath with subcooled He-2. For all cases examples of calculation and experimental data of heat exchanger tests are presented. The developed methods of calculation of heat exchangers for saturated He-2 and subcooled He-2 make it possible to design and create superfluid helium cryostatting systems

  5. Simultaneous estimation of arterial and venous oxygen saturation using a camera

    Science.gov (United States)

    van Gastel, Mark; Liang, Hangbing; Stuijk, Sander; de Haan, Gerard

    2018-02-01

    Optical monitoring of arterial blood oxygenation, SpO2, using cameras has recently been shown feasible by measuring the relative amplitudes of the remotely sensed PPG waveforms captured at different wavelengths. SvO2 measures the venous blood oxygenation which together with SpO2 provides an indication of tissue oxygen consumption. In contrast to SpO2 it usually still requires a blood sample from a pulmonary artery catheter. In this work we present a method which suggests simultaneous estimation of SpO2 and SvO2 with a camera. Contrary to earlier work, our method does not require external cuffs leading to better usability and improved comfort. Since the arterial blood varies synchronously with the heart rate, all frequencies outside the heart rate band are typically filtered out for SpO2 measurements. For SvO2 estimation, we include intensity variations in the respiratory frequency range since respiration modulates venous blood due to intrathoracic pressure variations in the chest and abdomen. Consequently, under static conditions, the two dominant components in the PPG signals are respiration and pulse. By measuring the amplitude ratios of these components, it seems possible to monitor both SpO2 and SvO2 continuously. We asked healthy subjects to follow an auditory breathing pattern while recording the face and hand. Results show a difference in estimated SpO2 and SvO2 values in the range 5-30 percent for both anatomical locations, which is normal for healthy people. This continuous, non-contact, method shows promise to alert the clinician to a change in patient condition sooner than SpO2 alone.

  6. Determination of oxygen in liquid sodium

    International Nuclear Information System (INIS)

    Torre, M. de la; Lapena, J.; Galindo, F.; Couchoud, M.; Celis, B. de; Lopez-Araquistain, J.L.

    1976-01-01

    The behaviour is analysed of a device for 'in-line' sampling and vacuum distillation. With this procedure 95 results were obtained for the solubility of oxygen in liquid sodium at temperatures between 125 0 and 300 0 C. The correlation between the concentration of oxygen in a saturation state and the corresponding temperature is represented by: 1g C = 6,17 - 2398/T, where C expressed ppm of oxygen by weight and T is the saturation temperature in 0 K. Reference is also made to the first results obtained with the electrochemical oxygen meter and the system for taking and recording data. (author)

  7. Anwendung der extrakorporalen Stoßwellentherapie bei kalzifizierender Periathropathia humeroscapularis, Fersensporn und Epicondylitis humeri - Erfahrungsbericht aus dem Wilhelminenspital

    Directory of Open Access Journals (Sweden)

    Feyertag J

    2004-01-01

    Full Text Available Die Stoßwellentherapie wird bei verschiedenen Indikationen, die unter konservativen Therapien schwer zu schwer zu behandeln sind, eingesetzt. Dazu zählen die kalzifizierenden Schultererkrankungen (Tendinitis calcarea, Epicondylitis humeri (EHR und die plantare Fasciitis mit/ohne plantarem Fersensporn (FSP. Berichtet werden die Ergebnisse von 147 Patienten (102 Frauen/45 Männer, mittleres Alter betrug 57,8 Jahre, die mittels einer einmaligen extrakorporalen Stoßwellentherapie (ESWT (Tend. calc. 82 %, FSP 11 % oder EHR 7 % mittels eines HMT-ReflecTron therapiert wurden. Verabreicht wurden im Mittel 1.800 Stoßwellen. Untersucht wurde die subjektive Verbesserung der Schmerzen anhand einer visuellen Analogskala vor und 6 Wochen nach der Therapie bei allen Patienten. Bei Patienten mit Tendinitis calcarea wurde auch eine Verbesserung der Funktion sowie Veränderungen der Kalzifizierungen untersucht. Bei allen Patienten konnte eine statistisch signifikante Verbesserung der Schmerzen sowie des Bewegungsumfanges beobachtet werden (p 0,0001. Röntgenaufnahmen ergaben eine partielle Verkleinerung der Kalkdepots bei ca. 80 % der Patienten. Aufgrund der geringen Zahl der Patienten fand sich für die EHR keine signifikante Verbesserung der Schmerzsymptomatik. Eine einmalige ESWT kann zu einer deutlichen Verbesserung der Schmerzsymptomatik und zu einer Verbesserung des Bewegungsumfanges führen. Bei 80 % der Patienten mit einer Tendinitis calcarea findet sich weiter eine partielle Verkleinerung der Kalkdepots 6 Wochen nach Therapie.

  8. Effect of oxygen treatment on heart rate after abdominal surgery

    DEFF Research Database (Denmark)

    Rosenberg-Adamsen, S; Lie, C; Bernhard, A

    1999-01-01

    BACKGROUND: Cardiac complications are common during the postoperative period and may be associated with hypoxemia and tachycardia. Preliminary studies in high-risk patients after operation have shown a possible beneficial effect of oxygen therapy on arterial oxygen saturation and heart rate....... METHODS: The authors studied the effect of oxygen therapy on arterial oxygen saturation and heart rate in 100 consecutive unselected patients randomly and double blindly allocated to receive air or oxygen therapy between the first and fourth day after major abdominal surgery. RESULTS: The median arterial...... oxygen saturation rate increased significantly from 96% to 99% (P heart rate decreased significantly from 85 beats/min to 81 beats/min (P heart rate occurred...

  9. Oxygen concentration inside a functioning photosynthetic cell.

    Science.gov (United States)

    Kihara, Shigeharu; Hartzler, Daniel A; Savikhin, Sergei

    2014-05-06

    The excess oxygen concentration in the photosynthetic membranes of functioning oxygenic photosynthetic cells was estimated using classical diffusion theory combined with experimental data on oxygen production rates of cyanobacterial cells. The excess oxygen concentration within the plesiomorphic cyanobacterium Gloeobactor violaceus is only 0.025 μM, or four orders of magnitude lower than the oxygen concentration in air-saturated water. Such a low concentration suggests that the first oxygenic photosynthetic bacteria in solitary form could have evolved ∼2.8 billion years ago without special mechanisms to protect them against reactive oxygen species. These mechanisms instead could have been developed during the following ∼500 million years while the oxygen level in the Earth's atmosphere was slowly rising. Excess oxygen concentrations within individual cells of the apomorphic cyanobacteria Synechocystis and Synechococcus are 0.064 and 0.25 μM, respectively. These numbers suggest that intramembrane and intracellular proteins in isolated oxygenic photosynthetic cells are not subjected to excessively high oxygen levels. The situation is different for closely packed colonies of photosynthetic cells. Calculations show that the excess concentration within colonies that are ∼40 μm or larger in diameter can be comparable to the oxygen concentration in air-saturated water, suggesting that species forming colonies require protection against reactive oxygen species even in the absence of oxygen in the surrounding atmosphere. Copyright © 2014 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  10. Clinical score and arterial oxygen saturation in children with wheezing associated respiratory illness (WARI).

    Science.gov (United States)

    Sritippayawan, S; Deerojanawong, J; Prapphal, N

    2000-10-01

    To determine the correlation between clinical score (based on respiratory rate, chest wall retractions, air entry, wheezing, consciousness and audible wheezing) and arterial oxygen saturation (SaO2: measured by pulse oximetry) as well as the most appropriate total score for predicting hypoxemia (SaO2 WARI). 70 children (1 month-5 years old) hospitalized in the Department of Pediatrics, Chulalongkorn Hospital with the diagnosis of WARI from January 1, 1996 to December 31, 1996 were studied. Half of them were diagnosed to have acute lower respiratory tract infection (LRI) with wheezing while the remainder had reactive airway disease (RAD). Cross sectional, analytical study. In each group of patients, the clinical score and SaO2 were assessed by the same pediatrician throughout the study. The correlation between the clinical signs and SaO2 as well as the cut off point of total score for predicting hypoxemia were analyzed. The sensitivity, specificity and accuracy of that total score in predicting hypoxemia were also calculated. In both groups of patients (acute LRI with wheezing and RAD group), the clinical signs correlated with SaO2 were wheezing (rs = -0.67 and -0.47 respectively) and chest wall retractions (rs = -0.57 and -0.59 respectively). Total score was also correlated with SaO2 (rs = -0.68 and -0.5 respectively). The cut off point of total score in predicting hypoxemia was 4 providing 80 per cent sensitivity in both groups with accuracy 74.3 per cent and 80 per cent respectively. This clinical score may be used to assess the severity of hypoxemia in WARI patients. Wheezing, chest wall retractions and total score correlated well with SaO2. The total score > 4 was most appropriate in predicting hypoxemia in both children with RAD and wheezing associated with LRI.

  11. Considerações sobre a idéia de tempo em Sto. Agostinho, Hume e Kant

    Directory of Open Access Journals (Sweden)

    Marcelo Carbone Carneiro

    2004-08-01

    Full Text Available Discute-se sobre o tempo buscando entendê-lo a partir dos referenciais que o tomam como elaboração subjetiva, ou seja, como não possuindo qualquer realidade fora do sujeito. Entende-se que, na história da Filosofia, esta reflexão inicia-se com a filosofia de Sto. Agostinho e tem seu ápice no pensamento moderno, sobretudo em Hume e Kant. O tempo seria uma construção ou elaboração do espírito, sem existência fora dele (Sto. Agostinho ou uma apreensão empírica regular de relações causais de antes e depois (Hume ou uma intuição pura do espírito (Kant. Pretende-se, com esta análise, evidenciar uma forma clássica de conceber o tempo como elaboração realizada pelo sujeito (subjetiva.

  12. Effect of oxygen clusters on optics, magnetism, and conductivity of (In2O3)0.9(SrO)0.1

    Science.gov (United States)

    Okunev, V. D.; Szymczak, H.; Szymczak, R.; Gierłowski, P.; Glot, A. B.; Bondarchuk, A. N.; Burkhovetski, V. V.

    2016-04-01

    We show that in In2O3-SrO ceramics with disordered structure and oxygen clusters in nanovoids, the band tails of valence and conduction bands form "negative" gap. Two types of magnetism are observed. One of them caused by formation of the "dangling bond+O2- ion" centers has been found in the samples saturated with oxygen. Another type is associated with the presence of dangling bonds in the oxygen-depleted samples. At Tconductivity of the samples. At T<54.8 K, the effects related to magnetic phase transitions in the clusters of crystalline oxygen are observed. The changes in resistance of the samples in the range of T=5-300 K correspond to the Mott's law at a dependence of local activation energy on the phase state of oxygen clusters.

  13. Evaluation of pulse-oximetry oxygen saturation taken through skin protective covering

    Science.gov (United States)

    James, Jyotsna; Tiwari, Lokesh; Upadhyay, Pramod; Sreenivas, Vishnubhatla; Bhambhani, Vikas; Puliyel, Jacob M

    2006-01-01

    Background The hard edges of adult finger clip probes of the pulse oximetry oxygen saturation (POOS) monitor can cause skin damage if used for prolonged periods in a neonate. Covering the skin under the probe with Micropore surgical tape or a gauze piece might prevent such injury. The study was done to see if the protective covering would affect the accuracy of the readings. Methods POOS was studied in 50 full-term neonates in the first week of life. After obtaining consent from their parents the neonates had POOS readings taken directly (standard technique) and through the protective covering. Bland-Altman plots were used to compare the new method with the standard technique. A test of repeatability for each method was also performed. Results The Bland-Altman plots suggest that there is no significant loss of accuracy when readings are taken through the protective covering. The mean difference was 0.06 (SD of 1.39) and 0.04 (SD 1.3) with Micropore and gauze respectively compared to the standard method. The mean difference was 0.22 (SD 0.23) on testing repeatability with the standard method. Conclusion Interposing Micropore or gauze does not significantly affect the accuracy of the POOS reading. The difference between the standard method and the new method was less than the difference seen on testing repeatability of the standard method. PMID:16677394

  14. Photoacoustic Imaging in Oxygen Detection

    Directory of Open Access Journals (Sweden)

    Fei Cao

    2017-12-01

    Full Text Available Oxygen level, including blood oxygen saturation (sO2 and tissue oxygen partial pressure (pO2, are crucial physiological parameters in life science. This paper reviews the importance of these two parameters and the detection methods for them, focusing on the application of photoacoustic imaging in this scenario. sO2 is traditionally detected with optical spectra-based methods, and has recently been proven uniquely efficient by using photoacoustic methods. pO2, on the other hand, is typically detected by PET, MRI, or pure optical approaches, yet with limited spatial resolution, imaging frame rate, or penetration depth. Great potential has also been demonstrated by employing photoacoustic imaging to overcome the existing limitations of the aforementioned techniques.

  15. One hour effects of salbutamol and formoterol on blood pressure, heart rate and oxygen saturation in asthmatics

    Directory of Open Access Journals (Sweden)

    Geraldo Andrade Capuchinho-Júnior

    2008-05-01

    Full Text Available Aim: To analyse systolic (SBP and diastolic blood pressure (DBP, partial oxygen saturation (SpO2 and heart rate (HR disorders for an hour after short and long acting ß2-agonists. Material and methods: Twenty-four severe persistent asthma Pulmonology outpatients at Hospital Universitario Gaffree e Guinle were selected. SBP, DBP, SpO2 and HR values were determined before and after 400 μg of salbutamol and 12 μg of formoterol, on different days, with a minimum interval of 24 hours. Results: All patients showed ventilatory obstruction, as seen by a reduced FEV1/FVC ratio. There was no statistical SBP/DBP/HR difference after bronchodilator agents, but SpO2 increased with salbutamol. Conclusion: A standard dose of salbutamol and formoterol does not cause haemodynamic disorder. Resumo: Objectivo: Analisar os possíveis efeitos do uso de β-2-agonistas, de curta e longa duração, nas pressões arteriais sistólica (PAS e diastólica (PAD, na saturação parcial de oxigénio (SpO2 e na frequência cardíaca (FC, durante o período de uma hora. Material e métodos: Vinte e quatro doentes com asma persistente grave, em tratamento no ambulatório de Pneumologia do Hospital Universitário Gaffrée e Guinle, foram seleccionados para um ensaio clínico sequencial e cruzado. Os valores da PAS, PAD, SpO2 e FC foram registados antes e após o uso de broncodilatadores, salbutamol 400 μg e formoterol 12 μg, em dias diferentes, com intervalo mínimo de 24 horas. Resultados: Todos os doentes apresentaram distúrbio ventilatório obstrutivo, identificado pela redução da relação entre o volume expiratório forçado no primeiro segundo (VEMS e a capacidade vital forçada (CVF. Após o uso de substância broncodilatadora, não houve variação significativa nas PAS e PAD, nem na FC; porém, a SpO2 aumentou com o uso de salbutamol. Conclusão: Não foram observadas

  16. Airborne geophysical survey of the catastrophic landslide at Stože, Log pod Mangrtom, as a test of an innovative approach for landslide mapping in steep alpine terrains

    Directory of Open Access Journals (Sweden)

    I. Baroň

    2013-10-01

    Full Text Available Airborne geophysics is a promising method for investigating landslides. Here we present a case study of multisensor airborne geophysical survey at the catastrophic landslide Stože near Log pod Mangrtom in Slovenia, which was conducted in the framework of the European FP7th Project "SafeLand". Based on the survey itself and achieved results, we discuss applicability, limits, and benefits and costs of the method for investigating landslides in steep alpine terrains. Despite of several operational constraints, the airborne electromagnetic survey of the area well presented the lithological pattern and water saturation. The high resistivity regions mostly indicated drained slope scree and landslide mass, drained and loosened material of the moraine deposit in the tension zone of the landslide with present cracks and cavities. The minima of the resistivity pattern were attributed to the outcrop of marls rich in clay, to water-saturated moraine deposit above impermeable marls in the tension zone, and to water-saturated porous alluvial gravel and landslide scree along the Koritnica River. The magnetic survey proved to be inapplicable for such a small and rough area. The Potassium and Thorium maps, on the other hand, both well identified the regions of tension inside the landslide zone, outcrops of marls and dolomite, clay-rich colluvium, weathered zones along a regional tectonic fault, and alluvial deposits and deposits of debris flows, and the minima of the 137Cs clearly revealed the zones of material removal due to recent mass movements.

  17. Effects of Changes in Arterial Carbon Dioxide and Oxygen Partial Pressures on Cerebral Oximeter Performance.

    Science.gov (United States)

    Schober, Andrew; Feiner, John R; Bickler, Philip E; Rollins, Mark D

    2018-01-01

    Cerebral oximetry (cerebral oxygen saturation; ScO2) is used to noninvasively monitor cerebral oxygenation. ScO2 readings are based on the fraction of reduced and oxidized hemoglobin as an indirect estimate of brain tissue oxygenation and assume a static ratio of arterial to venous intracranial blood. Conditions that alter cerebral blood flow, such as acute changes in PaCO2, may decrease accuracy. We assessed the performance of two commercial cerebral oximeters across a range of oxygen concentrations during normocapnia and hypocapnia. Casmed FORE-SIGHT Elite (CAS Medical Systems, Inc., USA) and Covidien INVOS 5100C (Covidien, USA) oximeter sensors were placed on 12 healthy volunteers. The fractional inspired oxygen tension was varied to achieve seven steady-state levels including hypoxic and hyperoxic PaO2 values. ScO2 and simultaneous arterial and jugular venous blood gas measurements were obtained with both normocapnia and hypocapnia. Oximeter bias was calculated as the difference between the ScO2 and reference saturation using manufacturer-specified weighting ratios from the arterial and venous samples. FORE-SIGHT Elite bias was greater during hypocapnia as compared with normocapnia (4 ± 9% vs. 0 ± 6%; P oxygen saturation and mixed venous oxygen tension, as well as increased oxygen extraction across fractional inspired oxygen tension levels (P oxygen extraction (P < 0.0001). Changes in PaCO2 affect cerebral oximeter accuracy, and increased bias occurs with hypocapnia. Decreased accuracy may represent an incorrect assumption of a static arterial-venous blood fraction. Understanding cerebral oximetry limitations is especially important in patients at risk for hypoxia-induced brain injury, where PaCO2 may be purposefully altered.

  18. Valence band electronic structure and band alignment of LaAlO{sub 3}/SrTiO{sub 3}(111) heterointerfaces

    Energy Technology Data Exchange (ETDEWEB)

    Gabel, J.; Scheiderer, P.; Zapf, M.; Schuetz, P.; Sing, M.; Claessen, R. [Physikalisches Institut and Roentgen Center for Complex Material Systems (RCCM), Universitaet Wuerzburg (Germany); Schlueter, C.; Lee, T.L. [Diamond Light Source, Didcot (United Kingdom)

    2015-07-01

    As in the famous LaAlO{sub 3}(LAO)/SrTiO{sub 3}(STO) (001) a two-dimensional electron system (2DES) also forms at the interface between LAO and STO in (111) orientation. A distinct feature of the (111) interface is its peculiar real space topology. Each bilayer represents a buckled honeycomb lattice similar to graphene which is known theoretically to host various topologically non-trivial states. Bilayer STO in proximity to the interface can be regarded as a three-orbital generalization of graphene with enhanced electron correlations making it a promising candidate for the realization of strongly correlated topological phases. We have investigated the electronic structure of the LAO/STO (111) heterostructure in relation to the oxygen vacancy concentration which we can control by synchrotron light irradiation and oxygen dosing. With hard X-ray photoemission we study the core levels, whereas resonant soft X-ray photoemission is used to probe the interfacial valence band (VB) states. Two VB features are found: a peak at the Fermi level associated with the 2DES and in-gap states at higher binding energies attributed to oxygen vacancies. By varying the oxygen vacancy contribution we can tune the emergence of the VB states and engineer the interfacial band alignment.

  19. Rejection of Erroneous Saturation Data in Optical Pulse Oximetry in Newborn Patients

    Science.gov (United States)

    Scalise, L.; Marchionni, Paolo; Carnielli, Virgilio P.

    2011-08-01

    Pulse oximetry (PO) is extensively used in intensive care unit (ICU); this is mainly due to the fact that it is a non-invasive and real-time monitoring method. PO allows to measure arterial oxygen saturation (SaO2) and in particular hemoglobin oxygenation. Optical PO is typically realized by the use of a clip (to be applied on the ear or on the finger top) containing a couple of monochromatic LED sources and a photodiode. The main drawback with the use of PO is the presence of movement artifacts or disturbance due to optical sources and skin, causing erroneous saturation data. The aim of this work is to present the measurement procedure based on a specially developed algorithm able to reject erroneous oxygen saturation data during long lasting monitoring of patients in ICU and to compare measurement data with reference data provided by EGA. We have collected SaO2 data from a standard PO and used an intensive care unit monitor to collect data. This device was connected to our acquisition system and heart rate (HR) and SaO2 data were acquired and processed by our specially developed algorithm and directly reproduced on the PC screen for use by the clinicians. The algorithm here used for the individuation and rejection of erroneous saturation data is based on the assessment of the difference between the Heart Rate (HR) measured by respectively by the ECG and PO. We have used an emogasanalyzer (EGA) for comparison of the measured data. The study was carried out in a neonatal intensive care unit (NICU), using 817 data coming from 24 patients and the observation time was of about 10000 hours. Results show a reduction in the maximum difference between the SaO2 data measured, simultaneously, on the same patient by the EGA and by the proposed method of 14.20% and of the 4.76% in average over the 817 samples. The measurement method proposed is therefore able to individuate and eliminate the erroneous saturation data due to motion artifacts and reported by the pulse oxymeter

  20. Asthma and hemoglobinopathy: when is supplemental oxygen required?

    Science.gov (United States)

    Joseph, Leon; Brickner-Braun, Inbal; Pinshow, Berry; Goldberg, Shmuel; Miskin, Hagit; Picard, Elie

    2013-10-01

    Asthma is the most common reason for referral to the emergency department in childhood. In severe attacks, supplemental O2 is given when oxygen saturation level is asthma attack. Simultaneously, P(a)O2 was normal. A diagnosis of abnormal hemoglobin with decreased oxygen affinity (hemoglobin Seattle) was made on hemoglobin electrophoresis and genetic analysis. To ascertain when supplemental oxygen was needed, an oxygen dissociation curve was plotted using the tonometer technique, and it was found that an S(p)O2 of 70% is parallel to a P(a)O2 of 60 mmHg. Plotting an oxygen dissociation curve is a simple reproducible method to determine when supplemental oxygen is required for a child with a hemoglobinopathy. © 2013 The Authors. Pediatrics International © 2013 Japan Pediatric Society.

  1. 2,3-diphosphoglycerate and oxygen supply of tissues in cardiosurgical diabetics.

    Science.gov (United States)

    Beder, I; Mataseje, A; Kittova, M; Carsky, J; Fischer, V

    2005-01-01

    The oxygen supply of tissues was studied under haemodilution in cardiosurgical diabetic and non-diabetic patients. There were 30 cardiosurgery patients examined, 9 were patients with diabetes mellitus.and 21 were non-diabetic patients. Venous blood samples were examined preoperatively, intraoperatively and for 10 days after operation. Haemodilution caused a decrease in haematocrit values in both groups, as well as in the erythrocyte count and haemoglobin concentration. Postoperatively, an increase was recorded in haematological values in both groups, the values had not reached the baseline even by 10th day. Increased values of blood oxygen saturation and partial oxygen pressure during the operation returned to baseline in both groups in the postoperative days. Values of p50 did not change in both groups for the period of observation. The obtained data suggest that sufficient oxygen supply to tissues was ensured under haemodilution in cardiosurgery patients in both groups. These results confirm multifactorial dependence of blood oxygen transport to tissues (Tab. 1, Fig. 3, Ref. 13).

  2. Transpeptidase activity of penicillin-binding protein SpoVD in peptidoglycan synthesis conditionally depends on the disulfide reductase StoA.

    Science.gov (United States)

    Bukowska-Faniband, Ewa; Hederstedt, Lars

    2017-07-01

    Endospore cortex peptidoglycan synthesis is not required for bacterial growth but essential for endospore heat resistance. It therefore constitutes an amenable system for research on peptidoglycan biogenesis. The Bacillus subtilis sporulation-specific class B penicillin-binding protein (PBP) SpoVD and many homologous PBPs contain two conserved cysteine residues of unknown function in the transpeptidase domain - one as residue x in the SxN catalytic site motif and the other in a flexible loop near the catalytic site. A disulfide bond between these residues blocks the function of SpoVD in cortex synthesis. With a combination of experiments with purified proteins and B. subtilis mutant cells, it was shown that in active SpoVD the two cysteine residues most probably interact by hydrogen bonding and that this is important for peptidoglycan synthesis in vivo. It was furthermore demonstrated that the sporulation-specific thiol-disulfide oxidoreductase StoA reduces SpoVD and that requirement of StoA for cortex synthesis can be suppressed by two completely different types of structural alterations in SpoVD. It is concluded that StoA plays a critical role mainly during maturation of SpoVD in the forespore outer membrane. The findings advance our understanding of essential PBPs and redox control of extra-cytoplasmic protein disulfides in bacterial cells. © 2017 The Authors. Molecular Microbiology Published by John Wiley & Sons Ltd.

  3. DFT study of oxygen adsorption on Mo{sub 2}C(001) and (201) surfaces at different conditions

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Lihong, E-mail: chenglihong001@126.com [School of Materials and Mechanical & Electrical Engineering, Jiangxi Science and Technology Normal University, Nanchang 330013, Jiangxi (China); Li, Wenkui; Chen, Zhiqin; Ai, Jianping; Zhou, Zehua [School of Materials and Mechanical & Electrical Engineering, Jiangxi Science and Technology Normal University, Nanchang 330013, Jiangxi (China); Liu, Jianwen, E-mail: liujw@nsccsz.gov.cn [National Supercomputing Center in Shenzhen, Shenzhen 518055 (China)

    2017-07-31

    Highlights: • O adsorption manners on Mo{sub 2}C surfaces were calculated by DFT method. • Stable oxygen adsorption states and coverage were identified at given T and p. • O{sub 2} results in full oxidation while H{sub 2}O and CO{sub 2} cause partial oxidation of Mo{sub 2}C surfaces. • Hydrogen could be used to avoid Mo{sub 2}C surface oxidation. - Abstract: Density functional theory (DFT) calculations were performed to investigate oxygen adsorption on Mo{sub 2}C(001) and (201)surfaces at different coverage. The energies and structures of oxygen from lowest to saturated coverages were clearly identified on each surface. Thermodynamics method was introduced to reveal the roles of temperature, pressure as well as oxygen sources (O{sub 2}, H{sub 2}O and CO{sub 2}) on the surface oxygen coverage, which is related to the surface oxidation. On the basis of phase diagram, we can easily identify the stable oxygen coverage at different defined conditions. In addition, it reveals that O{sub 2} is the strongest oxidant, which results in the full coverage of oxygen on both surfaces in a wide range of temperature and pressure. Then, H{sub 2}O and CO{sub 2} are weaker oxidants, which could only cause partial oxidation of Mo{sub 2}C surfaces. These results indicate the facile oxidation of Mo{sub 2}C catalyst. The possible ways to avoid surface oxidation are keeping higher temperature and H{sub 2} pressure in the gas phase.

  4. Induced nano-scale self-formed metal-oxide interlayer in amorphous silicon tin oxide thin film transistors.

    Science.gov (United States)

    Liu, Xianzhe; Xu, Hua; Ning, Honglong; Lu, Kuankuan; Zhang, Hongke; Zhang, Xiaochen; Yao, Rihui; Fang, Zhiqiang; Lu, Xubing; Peng, Junbiao

    2018-03-07

    Amorphous Silicon-Tin-Oxide thin film transistors (a-STO TFTs) with Mo source/drain electrodes were fabricated. The introduction of a ~8 nm MoO x interlayer between Mo electrodes and a-STO improved the electron injection in a-STO TFT. Mo adjacent to the a-STO semiconductor mainly gets oxygen atoms from the oxygen-rich surface of a-STO film to form MoO x interlayer. The self-formed MoO x interlayer acting as an efficient interface modification layer could conduce to the stepwise internal transport barrier formation while blocking Mo atoms diffuse into a-STO layer, which would contribute to the formation of ohmic contact between Mo and a-STO film. It can effectively improve device performance, reduce cost and save energy for the realization of large-area display with high resolution in future.

  5. Agreement between arterial partial pressure of carbon dioxide and saturation of hemoglobin with oxygen values obtained by direct arterial blood measurements versus noninvasive methods in conscious healthy and ill foals.

    Science.gov (United States)

    Wong, David M; Alcott, Cody J; Wang, Chong; Bornkamp, Jennifer L; Young, Jessica L; Sponseller, Brett A

    2011-11-15

    To determine agreement between indirect measurements of end-tidal partial pressure of carbon dioxide (PetCO(2)) and saturation of hemoglobin with oxygen as measured by pulse oximetry (SpO(2)) with direct measurements of PaCO(2) and calculated saturation of hemoglobin with oxygen in arterial blood (SaO(2)) in conscious healthy and ill foals. Validation study. 10 healthy and 21 ill neonatal foals. Arterial blood gas analysis was performed on healthy and ill foals examined at a veterinary teaching hospital to determine direct measurements of PaCO(2) and PaO(2) along with SaO(2). Concurrently, PetCO(2) was measured with a capnograph inserted into a naris, and SpO(2) was measured with a reflectance probe placed at the base of the tail. Paired values were compared by use of Pearson correlation coefficients, and level of agreement was assessed with the Bland-Altman method. Mean ± SD difference between PaCO(2) and PetCO(2) was 0.1 ± 5.0 mm Hg. There was significant strong correlation (r = 0.779) and good agreement between PaCO(2) and PetCO(2). Mean ± SD difference between SaO(2) and SpO(2) was 2.5 ± 3.5%. There was significant moderate correlation (r = 0.499) and acceptable agreement between SaO(2) and SpO(2). Both PetCO(2) obtained by use of nasal capnography and SpO(2) obtained with a reflectance probe are clinically applicable and accurate indirect methods of estimating and monitoring PaCO(2) and SaO(2) in neonatal foals. Indirect methods should not replace periodic direct measurement of corresponding parameters.

  6. Angiotensin-converting enzyme genotype and arterial oxygen saturation at high altitude in Peruvian Quechua.

    Science.gov (United States)

    Bigham, Abigail W; Kiyamu, Melisa; León-Velarde, Fabiola; Parra, Esteban J; Rivera-Ch, Maria; Shriver, Mark D; Brutsaert, Tom D

    2008-01-01

    The I-allele of the angiotensin-converting enzyme (ACE) gene insertion/deletion (I/D) polymorphism has been associated with performance benefits at high altitude (HA). In n = 142 young males and females of largely Quechua origins in Peru, we evaluated 3 specific hypotheses with regard to the HA benefits of the I-allele: (1) the I-allele is associated with higher arterial oxygen saturation (Sa(O(2))) at HA, (2) the I-allele effect depends on the acclimatization state of the subjects, and (3) the putative I-allele effect on Sa(O(2)) is mediated by the isocapnic hypoxic ventilatory response (HVR, l/min(1)/% Sa(O(2))(1)). The subject participants comprised two different study groups including BLA subjects (born at low altitude) who were lifelong sea-level residents transiently exposed to hypobaric hypoxia (<24 h) and BHA subjects (born at HA) who were lifelong residents of HA. To control for the possibility of population stratification, Native American ancestry proportion (NAAP) was estimated as a covariate for each individual using a panel of 70 ancestry-informative molecular markers (AIMS). At HA, resting and exercise Sa(O(2)) was strongly associated with the ACE genotype, p = 0.008 with approximately 4% of the total variance in Sa(O(2)) attributed to ACE genotype. Moreover, I/I individuals maintained approximately 2.3 percentage point higher Sa(O(2)) compared to I/D and D/D. This I-allele effect was evident in both BLA and BHA groups, suggesting that acclimatization state has little influence on the phenotypic expression of the ACE gene. Finally, ACE genotype was not associated with the isocapnic HVR, although HVR had a strong independent effect on Sa(O(2)) (p = 0.001). This suggests that the I-allele effect on Sa(O(2)) is not mediated by the peripheral control of breathing, but rather by some other central cardiopulmonary effect of the ACE gene on the renin-angiotensin-aldosterone system (RAAS).

  7. Overexpression of AtSTO1 leads to improved salt tolerance in Populus tremula × P. alba

    Science.gov (United States)

    Shaneka S. Lawson; Charles H. Michler

    2014-01-01

    One of the major abiotic stress conditions limiting healthy growth of trees is salinity stress. The use of gene manipulation for increased tolerance to abiotic stress has been successful in many plant species. Overexpression of the Arabidopsis SALT TOLERANT1 (STO1) gene leads to increased concentrations of 9-cis-epoxycarotenoid dioxygenase3, a vital...

  8. Postoperative Quality of Life after Total Gastrectomy Compared with Partial Gastrectomy: Longitudinal Evaluation by European Organization for Research and Treatment of Cancer-OG25 and STO22.

    Science.gov (United States)

    Lee, Jeong-Hwan; Lee, Hyuk-Joon; Choi, Yun Suk; Kim, Tae Han; Huh, Yeon-Ju; Suh, Yun-Suhk; Kong, Seong-Ho; Yang, Han-Kwang

    2016-12-01

    The European Organization for Research and Treatment of Cancer quality-of-life questionnaire-OG25 was developed to evaluate the quality of life in patients with stomach and esophageal cancer. The following are included in the OG25 but not in the STO22: odynophagia, choked when swallowing, weight loss, trouble eating with others, trouble swallowing saliva, trouble talking, and trouble with coughing. In this study, we evaluated the quality of life of gastrectomized patients using both, the OG25 and the STO22. A total of 138 patients with partial gastrectomy (PG) (distal gastrectomy=91; pylorus-preserving gastrectomy= 47) and 44 patients with total gastrectomy (TG) were prospectively evaluated. Body weight and scores from the OG25 and STO22 were evaluated preoperatively and at 3 weeks, 3 months, and 6 months after surgery. Patients with TG had significant weight loss compared to patients with PG. At 3 months, TG was associated with worse scores for dysphagia, eating, odynophagia, trouble eating with others, trouble with taste, and weight loss on the OG25. TG was also associated with dysphagia, eating restrictions, and anxiety on the STO22. The OG25 helped differentiate between the groups with respect to weight loss, odynophagia, choked when swallowing, and trouble eating with others. The OG25 scores changed over time and were significantly different. The OG25 is a more sensitive and useful scale than the STO22 for evaluating the quality of life of gastrectomized patients, especially those with total gastrectomy.

  9. Low-cost but accurate radioactive logging for determining gas saturation in a reservior

    International Nuclear Information System (INIS)

    Neuman, C.H.

    1976-01-01

    A method is disclosed for determining gas saturation in a petroleum reservoir using logging signals indirectly related to the abundances of oxygen and carbon nuclei in the reservoir rock. The first step of the invention is to record first and second logs sensitive to the abundance of oxygen and carbon nuclei, respectively, after the region surrounding the well bore is caused to have fluid saturations representative of the bulk of the reservoir. A purposeful change is then made in the fluid saturations in the region surrounding the well bore by injecting a liquid capable of displacing substantially all of the original fluids. The logs are recorded a second time. The displacing fluid is then itself displaced by brine, and a third suite of logs is recorded. The total fluid and oil saturations are then determined from the differences between respective corresponding logs and from known fractional volume oxygen and carbon contents of the reservoir brine and oil and the first injected liquid. Gas saturation is then calculated from differences between total fluid and oil saturation values. It is not necessary that the log responses be independent of the material in the borehole, the casing, the casing cement, or the reservoir rock. It is only necessary that changes in formation fluids content cause proportional changes in log responses. 7 Claims, 4 Figures

  10. Safety in the use of compressed air versus oxygen for the ophthalmic patient.

    Science.gov (United States)

    Rodgers, Laura A; Kulwicki, Anahid

    2002-02-01

    Oxygen, routinely administered during surgery to avoid hypoxia, poses risks including increased likelihood of surgical room fires and predisposition to retinal phototoxicity in patients. Compressed air to supplement ventilation may be safer than oxygen. The purpose of this study was to determine whether hypoxia occurs more frequently when compressed air replaces supplemental oxygen during ophthalmic surgery. A convenience sample of 111 patients was randomly assigned to receive supplemental oxygen (group 1) or compressed air (group 2). Patients with serious cardiac or pulmonary disease were excluded. Blood oxygen levels were monitored during surgery by pulse oximetry. Oxygen was administered to all group 2 patients whose oxygen saturation fell to less than 90% or by more than 5% below baseline. No differences were observed between groups in age, ASA classification, type of surgery, or anesthetic drugs or doses. Minor, but statistically higher oxygen values were observed in group 1. The frequency with which oxygen saturation decreased below 90% or below 5% of baseline was similar in both groups. Supplemental oxygen is not required routinely in selected patients undergoing ophthalmic surgery. By using compressed air, the risk of operating room fires and retinal phototoxicity may be reduced.

  11. A multiplexed electronic architecture for opto-electronic patch sensor to effectively monitor heart rate and oxygen saturation

    Science.gov (United States)

    Yan, Liangwen; Hu, Sijung; Alharbi, Samah; Blanos, Panagiotis

    2018-02-01

    To effectively capture human vital signs, a multi-wavelength optoelectronic patch sensor (MOEPS), together with a schematic architecture of electronics, was developed to overcome the drawbacks of present photoplethysmographic (PPG) sensors. To obtain a better performance of in vivo physiological measurement, the optimal illuminations, i.e., light emitting diodes (LEDs) in the MOEPS, whose wavelength is automatically adjusted to each specific subject, were selected to capture better PPG signals. A multiplexed electronic architecture has been well established to properly drive the MOEPS and effectively capture pulsatile waveforms at rest. The protocol was designed to investigate its performance with the participation of 11 healthy subjects aged between 18 and 30. The signals obtained from green (525nm) and orange (595nm) illuminations were used to extract heart rate (HR) and oxygen saturation (SpO2%). These results were compared with data, simultaneously acquired, from a commercial ECG and a pulse oximeter. Considering the difficulty for current devices to attain the SpO2%, a new computing method, to obtain the value of SpO2%, is proposed depended on the green and orange wavelength illuminations. The values of SpO2% between the MOEPS and the commercial Pulse Oximeter devics showed that the results were in good agreement. The values of HR showed close correlation between commercial devices and the MOEPS (HR: r1=0.994(Green); r2=0.992(Orange); r3=0.975(Red); r4=0.990(IR)).

  12. Calibration-free technique for the measurement of oxygen saturation changes in muscles of marine mammals and its proof of concept

    Science.gov (United States)

    Ortega-Martinez, Antonio; Goenka, Chhavi; Booker, Marloes; Grange, Robert M. H.; Hindle, Allyson G.; Franco, Walfre

    2018-02-01

    Marine mammals possess impressive breath-holding capabilities made possible by physiological adjustments during dives. Studying marine mammals in their natural environment unravels vital information about these physiological adjustments particularly when we can monitor altered dive behavior in response to stressful situations such as human-induced oceanic disturbances, presence of predators and altered prey distributions. An important indicator of physiological status during submergence is the change in oxygen saturation in the muscles and blood of these mammals. In this work, we aim to investigate oxygen storage and consumption in the muscles of free-diving elephant seals when exposed to disturbances such as sonar or predator sounds while they are at sea. Optical oxygen sensors are a mature technology with multiple medical applications that provide a way to measure oxygenation changes in biological tissues in a minimally invasive manner. While these sensors are well calibrated and readily available for humans, they are still inadequate for marine mammals primarily due to a very small number of test candidates and therefore little data is available for validation and calibration. We propose a probe geometry and associated mathematical model for measuring muscle oxygenation in seals based on near infrared diffuse transport with no need for calibration. A prototype based on this concept has been designed and tested on humans and rats. We use the test results to discuss the advantages and limitations of the approach. We also detail the constraints on size, sensor location, electronics, light source properties and detector characteristics posed by the unique biology of seals.

  13. Relationship between intraoperative regional cerebral oxygen saturation trends and cognitive decline after total knee replacement: a post-hoc analysis.

    Science.gov (United States)

    Salazar, Fátima; Doñate, Marta; Boget, Teresa; Bogdanovich, Ana; Basora, Misericordia; Torres, Ferran; Gracia, Isabel; Fàbregas, Neus

    2014-01-01

    Bilateral regional brain oxygen saturation (rSO2) trends, reflecting intraoperative brain oxygen imbalance, could warn of brain dysfunction. Various types of cognitive impairment, such as memory decline, alterations in executive function or subjective complaints, have been described three months after surgery. Our aim was to explore the potential utility of rSO2 values as a warning sign for the development of different types of decline in postoperative psychological function. Observational post-hoc analysis of data for the patient sample (n = 125) of a previously conducted clinical trial in patients over the age of 65 years undergoing total knee replacement under spinal anesthesia. Demographic, hemodynamic and bilateral rSO2 intraoperative values were recorded. An absolute rSO2 value of 20% or >25% below baseline were chosen as relevant cutoffs. Composite function test scores were created from baseline to three months for each patient and adjusted for the mean (SD) score changes for a control group (n = 55). Tests were used to assess visual-motor coordination and executive function (VM-EF) (Wechsler Digit Symbol-Coding and Visual Reproduction, Trail Making Test) and memory (Auditory Verbal Learning, Wechsler Memory Scale); scales were used to assess psychological symptoms. We observed no differences in baseline rSO2 values; rSO2 decreased significantly in all patients during surgery (P Left and right rSO2 values were asymmetric in patients who had memory decline (mean [SD] left-right ratio of 95.03 [8.51] vs 101.29 [6.7] for patients with no changes, P = 0.0012). The mean right-left difference in rSO2 was also significant in these patients (-2.87% [4.73%], lower on the right, P = 0.0034). Detection of a trend to asymmetry in rSO2 values can warn of possible postoperative onset of memory decline. Psychological symptoms and memory decline were common three months after knee replacement in our patients over the age of 65 years.

  14. Cardiac function and oxygen saturation during maximal breath-holding in air and during whole-body surface immersion.

    Science.gov (United States)

    Marabotti, Claudio; Piaggi, Paolo; Menicucci, Danilo; Passera, Mirko; Benassi, Antonio; Bedini, Remo; L'Abbate, Antonio

    2013-09-01

    The magnitude of the oxygen-sparing effect induced by the diving response in humans is still under debate. We wished to compare cardiovascular changes during maximal breath-holding (BH) in air and during whole-body immersion at the surface in a group of BH divers. Twenty-one divers performed a maximal static apnea in air or during whole-body immersion. Dopplerechocardiography, arterial blood pressure and haemoglobin saturation (SaO₂) were obtained at the beginning of, and at 1/3, 2/3 and maximal BH time. BH time was on the average 3.6 ± 0.4 min, with no differences between the two conditions. SaO₂ significantly decreased during BH in both conditions, but was significantly higher during immersion as compared to the dry (P = 0.04). In both conditions, BH induced a significant linear increase in right ventricular diameter (P whole-body immersion, associated with reduced LV ejection fraction and progressive hindrance to diastolic filling. For a similar apnea duration, SaO₂ decreased less during immersed BH, indicating an O₂-sparing effect of diving, suggesting that interruption of apnea was not triggered by a threshold critical value of blood O₂ desaturation.

  15. Interplay between O2 and SnO2: oxygen ionosorption and spectroscopic evidence for adsorbed oxygen.

    Science.gov (United States)

    Gurlo, Alexander

    2006-10-13

    Tin dioxide is the most commonly used material in commercial gas sensors based on semiconducting metal oxides. Despite intensive efforts, the mechanism responsible for gas-sensing effects on SnO(2) is not fully understood. The key step is the understanding of the electronic response of SnO(2) in the presence of background oxygen. For a long time, oxygen interaction with SnO(2) has been treated within the framework of the "ionosorption theory". The adsorbed oxygen species have been regarded as free oxygen ions electrostatically stabilized on the surface (with no local chemical bond formation). A contradiction, however, arises when connecting this scenario to spectroscopic findings. Despite trying for a long time, there has not been any convincing spectroscopic evidence for "ionosorbed" oxygen species. Neither superoxide ions O(2)(-), nor charged atomic oxygen O,(-) nor peroxide ions O(2)(2-) have been observed on SnO(2) under the real working conditions of sensors. Moreover, several findings show that the superoxide ion does not undergo transformations into charged atomic oxygen at the surface, and represents a dead-end form of low-temperature oxygen adsorption on reduced metal oxide.

  16. Near-Infrared Spectroscopic Measurement of the Effect of Leg Dominance on Muscle Oxygen Saturation During Cycling

    Science.gov (United States)

    Ellerby, Gwenn E. C.; Lee, Stuart M. C.; Paunescu, Lelia Adelina; Pereira, Chelsea; Smith, Charles P.; Soller, Babs R.

    2011-01-01

    The effect of leg dominance on the symmetry of the biomechanics during cycling remains uncertain -- asymmetries have been observed in kinematics and kinetics, while symmetries were found in muscle activation. No studies have yet investigated the symmetry of muscle metabolism during cycling. Near-infrared spectroscopy (NIRS) provides a non-invasive method to investigate the metabolic responses of specific muscles during cycling. PURPOSE: To determine whether there was an effect of leg dominance on thigh muscle oxygen saturation (SmO2) during incrementally loaded submaximal cycling using NIRS. METHODS: Eight right leg dominant, untrained subjects (5 men, 3 women; 31+/-2 yrs; 168.6+/-1.0 cm; 67.2+/-1.8 kg, mean +/- SE) volunteered to participate. Spectra were collected bilaterally from the vastus lateralis (VL) during supine rest and cycling. SmO2 was calculated using previously published methods. Subjects pedaled at 65 rpm while resistance to pedaling was increased in 0.5 kp increments from 0.5 kp every 3 min until the subject reached 80% of age-predicted maximal heart rate. SmO2 was averaged over 3 min for each completed stage. A two-way ANOVA was performed to test for leg differences. A priori contrasts were used to compare work levels to rest. RESULTS: VL SmO2 was not different between the dominant and non-dominant legs at rest and during exercise (p=0.57). How SmO2 changed with workload was also not different between legs (p=0.32). SmO2 at 0.5 kp (60.3+/-4.0, p=0.12) and 1.0 kp (59.5+/-4.0, p=0.10) was not different from rest (69.1+/-4.0). SmO2 at 1.5 kp (55.4 4.0, p=0.02), 2.0 kp (55.7+/-5.0, p=0.04), and 2.5 kp (43.4+/-7.9, p=0.01) was significantly lower than rest. CONCLUSION: VL SmO2 during cycling is not different between dominant and non-dominant legs and decreases with moderate workload in untrained cyclists. Assuming blood flow is directed equally to both legs, similar levels of oxygen extraction (as indicated by SmO2) suggests the metabolic load of

  17. Data on the effect of target temperature management at 32–34 °C in cardiac arrest patients considering assessment by regional cerebral oxygen saturation: A multicenter retrospective cohort study

    Directory of Open Access Journals (Sweden)

    Yuka Nakatani

    2018-04-01

    Full Text Available This data article contains raw data and supplementary analyzed data regarding to the article entitled “Effect of target temperature management at 32–34 °C in cardiac arrest patients considering assessment by regional cerebral oxygen saturation: A multicenter retrospective cohort study”. We examined the effectiveness of target temperature management (TTM at 32–34 °C considering degrees of patients’ cerebral injury and cerebral circulation assessed by regional cerebral oxygen saturation (rSO2. The research is a secondary analysis of prospectively collected registry, in which comatose patients who were transferred to 15 hospitals in Japan after out-of-hospital cardiac arrest (OHCA, and we included 431 study patients. Propensity score analysis revealed that TTM at 32–34 °C decreased all-cause mortality in patients with rSO2 41–60%, and increased favorable neurological outcomes in patients with rSO2 41–60% in the original research article. With regard to the balance of covariates of propensity-score matching (PSM and inverse-probability weighting (IPW analyses, some covariates were not well balanced after the analyses between groups. The overlap plots indicate the overlap of densities of the propensity scores are low in group rSO2 41–60% and group rSO2 ≥ 61%. When patients were limited to those who achieved return of spontaneous circulation (ROSC until/on hospitals arrival, TTM still tended to decrease all-cause mortality and increase favorable outcomes in group rSO2 41–60%.

  18. Corrosion behavior of austenitic and ferritic/martensitic steels in oxygen-saturated liquid Pb-Bi eutectic at 450circC and 550circC

    OpenAIRE

    倉田 有司; 二川 正敏; 斎藤 滋

    2005-01-01

    Static corrosion tests of various austenitic and ferritic/martensitic steels were conducted in oxygen-saturated liquid Pb-Bi at 450circC and 550circC for 3000h to study the effects of temperature and alloying elements on corrosion behavior. Oxidation, grain boundary corrosion, dissolution and penetration were observed. The corrosion depth decreases at 450circC with increasing Cr content in steels regardless of ferritic/martensitic or austenitic steels. Appreciable dissolution of Ni and Cr doe...

  19. Assessment of the oxygen consumption in the backfill. Geochemical modelling in a saturated backfill

    International Nuclear Information System (INIS)

    Grandia, Fidel; Domenech, Cristina; Arcos, David; Duro, Lara

    2006-11-01

    The consumption of oxygen in the deep disposal is a major concern due to the ability of this element to corrode the canisters where high level nuclear wastes (HLNW) are disposed. The anoxic conditions initially present in a deep geologic environment are disturbed by the excavation of the repository facilities. After sealing the deposition holes and tunnels using clay-based materials, oxygen remains dissolved in porewater or as a gas phase in the unsaturated pores. The main mechanisms of oxygen depletion that can be considered in the backfill materials are: (1) diffusion into the surrounding rock and (2) kinetic reactions with accessory minerals and organic matter existing in the backfill. In this report, a set of numerical simulations are carried out in one and two dimensions in order to test the effect on the oxygen concentration in the pore water of all these mechanisms. The backfill considered is a 0/70 mixture of MX-80 bentonite and crushed material from the excavation itself. In addition to organic matter, the solid phases with reducing capacity in the backfill are Fe(II)-bearing minerals: pyrite (FeS 2 ) and siderite (FeCO) (as accessory minerals in the bentonite) and Fe-biotite (from the crushed granite). In the simulations, other chemical processes like cation exchange and surface complexation onto clay surfaces, and thermodynamic equilibrium with calcite, gypsum and quartz are considered. Initial composition of porewater is obtained by equilibrating the Forsmark groundwater with the backfill material. The 1D simulation consists of a number of cells with no reactive minerals or organic matter representing granite. The central cell, however, contains oxygen and reactive minerals resembling a backfill. Oxygen is allowed to move only by diffusion. The 2D model simulates the interaction with a backfill of a granitic groundwater flowing through a fracture. Like in the 1D model, the backfill contains oxygen and reactive solids. The results are very similar in

  20. Assessment of the oxygen consumption in the backfill. Geochemical modelling in a saturated backfill

    Energy Technology Data Exchange (ETDEWEB)

    Grandia, Fidel; Domenech, Cristina; Arcos, David; Duro, Lara [Enviros Spain S.L., Barcelona (Spain)

    2006-11-15

    The consumption of oxygen in the deep disposal is a major concern due to the ability of this element to corrode the canisters where high level nuclear wastes (HLNW) are disposed. The anoxic conditions initially present in a deep geologic environment are disturbed by the excavation of the repository facilities. After sealing the deposition holes and tunnels using clay-based materials, oxygen remains dissolved in porewater or as a gas phase in the unsaturated pores. The main mechanisms of oxygen depletion that can be considered in the backfill materials are: (1) diffusion into the surrounding rock and (2) kinetic reactions with accessory minerals and organic matter existing in the backfill. In this report, a set of numerical simulations are carried out in one and two dimensions in order to test the effect on the oxygen concentration in the pore water of all these mechanisms. The backfill considered is a 0/70 mixture of MX-80 bentonite and crushed material from the excavation itself. In addition to organic matter, the solid phases with reducing capacity in the backfill are Fe(II)-bearing minerals: pyrite (FeS{sub 2}) and siderite (FeCO) (as accessory minerals in the bentonite) and Fe-biotite (from the crushed granite). In the simulations, other chemical processes like cation exchange and surface complexation onto clay surfaces, and thermodynamic equilibrium with calcite, gypsum and quartz are considered. Initial composition of porewater is obtained by equilibrating the Forsmark groundwater with the backfill material. The 1D simulation consists of a number of cells with no reactive minerals or organic matter representing granite. The central cell, however, contains oxygen and reactive minerals resembling a backfill. Oxygen is allowed to move only by diffusion. The 2D model simulates the interaction with a backfill of a granitic groundwater flowing through a fracture. Like in the 1D model, the backfill contains oxygen and reactive solids. The results are very similar in

  1. Effect of temperature on the metabolism, behaviour and oxygen requirements of Sparus aurata

    NARCIS (Netherlands)

    Remen, M.; Nederlof, M.A.J.; Folkedal, O.; Thorsheim, G.; Sitjà-Bobadilla, A.; Pérez-Sánchez, J.; Oppedal, F.; Olsen, R.E.

    2015-01-01

    We investigated the effect of temperature on the limiting oxygen saturation (LOS) of gilthead sea bream Sparus aurata. This threshold was defined as the % O2 saturation where fish no longer upheld their routine metabolic rate (RMR, the metabolic rate of fed and active fish) during a progressive

  2. A theoretical model for the effects of reduced hemoglobin-oxygen affinity on tumor oxygenation

    International Nuclear Information System (INIS)

    Kavanagh, Brian D.; Secomb, Timothy W.; Hsu, Richard; Lin, P.-S.; Venitz, Jurgen; Dewhirst, Mark W.

    2002-01-01

    Purpose: To develop a theoretical model for oxygen delivery to tumors, and to use the model to simulate the effects of changing the affinity of hemoglobin for oxygen on tumor oxygenation. Methods and Materials: Hemoglobin affinity is expressed in terms of P 50 , the partial pressure of oxygen (Po 2 ) at half saturation. Effects of changing P 50 on arterial Po 2 are predicted using an effective vessel approach to describe diffusive oxygen transport in the lungs, assuming fixed systemic oxygen demand and fixed blood flow rate. The decline in oxygen content of blood as it flows through normal tissue before entering the tumor region is assumed fixed. The hypoxic fraction of the tumor region is predicted using a three-dimensional simulation of diffusion from a network of vessels whose geometry is derived from observations of tumor microvasculature in the rat. Results: In air-breathing rats, predicted hypoxic fraction decreases with moderate increases in P 50 , but increases with further increases of P 50 , in agreement with previous experimental results. In rats breathing hyperoxic gases, and in humans breathing either normoxic or hyperoxic gases, increased P 50 is predicted to improve tumor oxygenation. Conclusions: The results support the administration of synthetic agents to increase P 50 during radiation treatment of tumors

  3. In vivo imaging of cerebral hemodynamics and tissue scattering in rat brain using a surgical microscope camera system

    Science.gov (United States)

    Nishidate, Izumi; Kanie, Takuya; Mustari, Afrina; Kawauchi, Satoko; Sato, Shunichi; Sato, Manabu; Kokubo, Yasuaki

    2018-02-01

    We investigated a rapid imaging method to monitor the spatial distribution of total hemoglobin concentration (CHbT), the tissue oxygen saturation (StO2), and the scattering power b in the expression of musp=a(lambda)^-b as the scattering parameters in cerebral cortex using a digital red-green-blue camera. In the method, Monte Carlo simulation (MCS) for light transport in brain tissue is used to specify a relation among the RGB-values and the concentration of oxygenated hemoglobin (CHbO), that of deoxygenated hemoglobin (CHbR), and the scattering power b. In the present study, we performed sequential recordings of RGB images of in vivo exposed brain of rats while changing the fraction of inspired oxygen (FiO2), using a surgical microscope camera system. The time courses of CHbO, CHbR, CHbT, and StO2 indicated the well-known physiological responses in cerebral cortex. On the other hand, a fast decrease in the scattering power b was observed immediately after the respiratory arrest, which is similar to the negative deflection of the extracellular DC potential so-called anoxic depolarization. It is said that the DC shift coincident with a rise in extracellular potassium and can evoke cell deformation generated by water movement between intracellular and extracellular compartments, and hence the light scattering by tissue. Therefore, the decrease in the scattering power b after the respiratory arrest is indicative of changes in light scattering by tissue. The results in this study indicate potential of the method to evaluate the pathophysiological conditions and loss of tissue viability in brain tissue.

  4. The human ear canal: investigation of its suitability for monitoring photoplethysmographs and arterial oxygen saturation

    International Nuclear Information System (INIS)

    Budidha, K; Kyriacou, P A

    2014-01-01

    For the last two decades, pulse oximetry has been used as a standard procedure for monitoring arterial oxygen saturation (SpO 2 ). However, SpO 2 measurements made from extremities such as the finger, ear lobe and toes become susceptible to inaccuracies when peripheral perfusion is compromised. To overcome these limitations, the external auditory canal has been proposed as an alternative monitoring site for estimating SpO 2 , on the hypothesis that this central site will be better perfused. Therefore, a dual wavelength optoelectronic probe along with a processing system was developed to investigate the suitability of measuring photoplethysmographic (PPG) signals and SpO 2 in the human auditory canal. A pilot study was carried out in 15 healthy volunteers to validate the feasibility of measuring PPGs and SpO 2  from the ear canal (EC), and comparative studies were performed by acquiring the same signals from the left index finger (LIF) and the right index finger (RIF) in conditions of induced peripheral vasoconstriction (right hand immersion in ice water). Good quality baseline PPG signals with high signal-to-noise ratio were obtained from the EC, the LIF and the RIF sensors. During the ice water immersion, significant differences in the amplitude of the red and infrared PPG signals were observed from the RIF and the LIF sensors. The average drop in amplitude of red and infrared PPG signals from the RIF was 52.7% and 58.3%. Similarly, the LIF PPG signal amplitudes have reduced by 47.52% and 46.8% respectively. In contrast, no significant changes were seen in the red and infrared EC PPG amplitude measurements, which changed by +2.5% and −1.2% respectively. The RIF and LIF pulse oximeters have failed to estimate accurate SpO 2  in seven and four volunteers respectively, while the EC pulse oximeter has only failed in one volunteer. These results suggest that the EC may be a suitable site for reliable monitoring of PPGs and SpO 2 s even in the presence of

  5. Quantification of photocatalytic oxygenation of human blood.

    Science.gov (United States)

    Subrahmanyam, Aryasomayajula; Thangaraj, Paul R; Kanuru, Chandrasekhar; Jayakumar, Albert; Gopal, Jayashree

    2014-04-01

    Photocatalytic oxygenation of human blood is an emerging concept based on the principle of photocatalytic splitting of water into oxygen and hydrogen. This communication reports: (i) a design of a photocatalytic cell (PC) that separates the blood from UV (incident) radiation source, (ii) a pH, temperature and flow controlled circuit designed for quantifying the oxygenation of human blood by photocatalysis and (iii) measuring the current efficacy of ITO/TiO2 nano thin films in oxygenating human blood in a dynamic circuit in real time. The average increase in oxygen saturation was around 5% above baseline compared to control (p<0.0005). We believe this is one of the first attempts to quantify photocatalytic oxygenation of human blood under controlled conditions. Copyright © 2013 IPEM. Published by Elsevier Ltd. All rights reserved.

  6. Tackling the Saturation of Oxygen: The Use of Phosphorus and Sulfur as Proxies within the Neutral Interstellar Medium of Star-forming Galaxies

    Science.gov (United States)

    James, B.; Aloisi, A.

    2018-02-01

    The abundance of oxygen in galaxies is widely used in furthering our understanding of galaxy formation and evolution. Unfortunately, direct measurements of O/H in the neutral gas are extremely difficult to obtain, as the only O I line available within the Hubble Space Telescope (HST) UV wavelength range (1150–3200 Å) is often saturated. As such, proxies for oxygen are needed to indirectly derive O/H via the assumption that solar ratios based on local Milky Way sight lines hold in different environments. In this paper we assess the validity of using two such proxies, P II and S II, within more typical star-forming environments. Using HST-Cosmic Origins Spectrograph (COS) far-UV (FUV) spectra of a sample of nearby star-forming galaxies (SFGs) and the oxygen abundances in their ionized gas, we demonstrate that both P and S are mildly depleted with respect to O and follow a trend, log(P II/S II) = -1.73 +/- 0.18, in excellent agreement with the solar ratio of {log}{({{P}}/{{S}})}ȯ =-1.71 +/- 0.04 over the large range of metallicities (0.03–3.2 Z ⊙) and H I column densities ({log}[N(H I)/cm‑2] =18.44–21.28) spanned by the sample. From literature data we show evidence that both elements individually trace oxygen according to their respective solar ratios across a wide range of environments. Our findings demonst-rate that the solar ratios of {log}{({{P}}/{{O}})}ȯ =-3.28+/- 0.06 and {log}{({{S}}/{{O}})}ȯ =-1.57+/- 0.06 can both be used to derive reliable O/H abundances in the neutral gas of local and high-redshift SFGs. The difference between O/H in the ionized- and neutral gas phases is studied with respect to metallicity and H I content. The observed trends are consistent with galactic outflows and/or star formation inefficiency affecting the most metal-poor galaxies, with the possibility of primordial gas accretion at all metallicities.

  7. Intraoperative optical assessment of photodynamic therapy response of superficial oral squamous cell carcinoma

    Science.gov (United States)

    Rohrbach, Daniel J.; Rigual, Nestor; Arshad, Hassan; Tracy, Erin C.; Cooper, Michelle T.; Shafirstein, Gal; Wilding, Gregory; Merzianu, Mihai; Baumann, Heinz; Henderson, Barbara W.; Sunar, Ulas

    2016-01-01

    This study investigated whether diffuse optical spectroscopy (DOS) measurements could assess clinical response to photodynamic therapy (PDT) in patients with head and neck squamous cell carcinoma (HNSCC). In addition, the correlation between parameters measured with DOS and the crosslinking of signal transducer and activator of transcription 3 (STAT3), a molecular marker for PDT-induced photoreaction, was investigated. Thirteen patients with early stage HNSCC received the photosensitizer 2-[1-hexyloxyethyl]-2-devinylpyropheophorbide-a (HPPH) and DOS measurements were performed before and after PDT in the operating room (OR). In addition, biopsies were acquired after PDT to assess the STAT3 crosslinking. Parameters measured with DOS, including blood volume fraction, blood oxygen saturation (StO2), HPPH concentration (cHPPH), HPPH fluorescence, and blood flow index (BFI), were compared to the pathologic response and the STAT3 crosslinking. The best individual predictor of pathological response was a change in cHPPH (sensitivity=60%, specificity=100%), while discrimination analysis using a two-parameter classifier (change in cHPPH and change in StO2) classified pathological response with 100% sensitivity and 100% specificity. BFI showed the best correlation with the crosslinking of STAT3. These results indicate that DOS-derived parameters can assess the clinical response in the OR, allowing for earlier reintervention if needed.

  8. Phenobarbital and neonatal seizures affect cerebral oxygen metabolism: a near-infrared spectroscopy study.

    Science.gov (United States)

    Sokoloff, Max D; Plegue, Melissa A; Chervin, Ronald D; Barks, John D E; Shellhaas, Renée A

    2015-07-01

    Near-infrared spectroscopy (NIRS) measures oxygen metabolism and is increasingly used for monitoring critically ill neonates. The implications of NIRS-recorded data in this population are poorly understood. We evaluated NIRS monitoring for neonates with seizures. In neonates monitored with video-electroencephalography, NIRS-measured cerebral regional oxygen saturation (rSO2) and systemic O2 saturation were recorded every 5 s. Mean rSO2 was extracted for 1-h blocks before, during, and after phenobarbital doses. For each electrographic seizure, mean rSO2 was extracted for a period of three times the duration of the seizure before and after the ictal pattern, as well as during the seizure. Linear mixed models were developed to assess the impact of phenobarbital administration and of seizures on rSO2 and fractional tissue oxygen extraction. For 20 neonates (estimated gestational age: 39.6 ± 1.5 wk), 61 phenobarbital doses and 40 seizures were analyzed. Cerebral rSO2 rose (P = 0.005), and fractional tissue oxygen extraction declined (P = 0.018) with increasing phenobarbital doses. rSO2 declined during seizures, compared with baseline and postictal phases (baseline 81.2 vs. ictal 77.7 vs. postictal 79.4; P = 0.004). Fractional tissue oxygen extraction was highest during seizures (P = 0.002). Cerebral oxygen metabolism decreases after phenobarbital administration and increases during seizures. These small, but clear, changes in cerebral oxygen metabolism merit assessment for potential clinical impact.

  9. Microbial endogenous response to acute inhibitory impact of antibiotics.

    Science.gov (United States)

    Pala-Ozkok, I; Kor-Bicakci, G; Çokgör, E U; Jonas, D; Orhon, D

    2017-06-13

    Enhanced endogenous respiration was observed as the significant/main response of the aerobic microbial culture under pulse exposure to antibiotics: sulfamethoxazole, tetracycline and erythromycin. Peptone mixture and acetate were selected as organic substrates to compare the effect of complex and simple substrates. Experiments were conducted with microbial cultures acclimated to different sludge ages of 10 and 2 days, to visualize the effect of culture history. Evaluation relied on modeling of oxygen uptake rate profiles, reflecting the effect of all biochemical reactions associated with substrate utilization. Model calibration exhibited significant increase in values of endogenous respiration rate coefficient with all antibiotic doses. Enhancement of endogenous respiration was different with antibiotic type and initial dose. Results showed that both peptone mixture and acetate cultures harbored resistance genes against the tested antibiotics, which suggests that biomass spends cellular maintenance energy for activating the required antibiotic resistance mechanisms to survive, supporting higher endogenous decay rates. [Formula: see text]: maximum growth rate for X H (day -1 ); K S : half saturation constant for growth of X H (mg COD/L); b H : endogenous decay rate for X H (day -1 ); k h : maximum hydrolysis rate for S H1 (day -1 ); K X : hydrolysis half saturation constant for S H1 (mg COD/L); k hx : maximum hydrolysis rate for X S1 (day -1 ); K XX : hydrolysis half saturation constant for X S1 (mg COD/L); k STO : maximum storage rate of PHA by X H (day -1 ); [Formula: see text]: maximum growth rate on PHA for X H (day -1 ); K STO : half saturation constant for storage of PHA by X H (mg COD/L); X H1 : initial active biomass (mg COD/L).

  10. Oxygen Concentration Inside a Functioning Photosynthetic Cell

    OpenAIRE

    Kihara, Shigeharu; Hartzler, Daniel A.; Savikhin, Sergei

    2014-01-01

    The excess oxygen concentration in the photosynthetic membranes of functioning oxygenic photosynthetic cells was estimated using classical diffusion theory combined with experimental data on oxygen production rates of cyanobacterial cells. The excess oxygen concentration within the plesiomorphic cyanobacterium Gloeobactor violaceus is only 0.025 μM, or four orders of magnitude lower than the oxygen concentration in air-saturated water. Such a low concentration suggests that the first oxygenic...

  11. The evaluation of cerebral oxygenation by oximetry in patients with ischaemic stroke.

    Directory of Open Access Journals (Sweden)

    Demet G

    2000-04-01

    Full Text Available AIMS: To evaluate the clinical significance of estimation of the regional cerebral oxygen saturation (rSO2 in the patients with ischaemic stroke by the cerebral oximetry during acute, sub-acute and chronic phases. SUBJECTS AND METHODS: In this prospective study, 24 patients with ischaemic stroke in the middle cerebral artery territory were included. A detailed clinical examination and appropriate laboratory investigations were carried out. The rSO2 was determined by oximetery (INVOS 3100-SD bilaterally on the first, third, seventh, and fifteenth days. The blood pressure, the peripheral capillary oxygen saturation and the arterial blood gas values were noted too. the changes were evaluated along with Glasgow coma scale (GCS using unpaired student t-test and one way ANOVA test. RESULTS: There were significant differences between the rSO2 values in acute, subacute and chronic phases on the side of the lesion (p value < 0.05. The values of oxygen saturation gradually increased throughout the chronic phase. These values showed a positive correlation with GCS, but the results were not significant statistically. The rSO2 values were also significantly higher on the non-lesional side than those on the lesion side in the acute phase (p= 0.0034, the discrepancy disappeared during the sub-acute and chronic phases. CONCLUSION: Cerebral oximetry can be used as a measure to evaluate the cerebral oxygenation during the various phases of ischaemic stroke. It has a potential to serve as a useful marker for detection of cerebral oxygenation imbalances, to judge the effectiveness of the management and for the follow-up of patients with ischaemic stroke.

  12. Singlet oxygen quenching by oxygen in tetraphenyl-porphyrin solutions

    International Nuclear Information System (INIS)

    Dedic, Roman; Korinek, Miloslav; Molnar, Alexander; Svoboda, Antonin; Hala, Jan

    2006-01-01

    Time-resolved measurement of singlet oxygen infrared phosphorescence is a powerful tool for determination of quantum yields and kinetics of its photosensitization. This technique was employed to investigate in detail the previously observed effect of singlet oxygen quenching by oxygen. The question whether the singlet oxygen is quenched by oxygen in ground or in excited state was addressed by study of two complementary dependencies of singlet oxygen lifetimes: on dissolved oxygen concentration and on excitation intensity. Oxygen concentration dependence study of meso-tetra(4-sulphonato)phenylporphyrin (TPPS 4 ) phosphorescence kinetics showed linearity of the dependence of TPPS 4 triplet state rate-constant. Corresponding bimolecular quenching constant of (1.5±0.1)x10 9 l/mol s was obtained. On the other hand, rate constants of singlet oxygen depopulation exhibit nonlinear dependence on oxygen concentration. Comparison of zero oxygen concentration-extrapolated value of singlet oxygen lifetime of (6.5±0.4) μs to (3.7±0.1) μs observed under air-saturated conditions indicates importance of the effect of quenching of singlet oxygen by oxygen. Upward-sloping dependencies of singlet oxygen depopulation rate-constant on excitation intensity evidence that singlet oxygen is predominantly quenched by oxygen in excited singlet state

  13. Carbon Dioxide Fluctuations Are Associated with Changes in Cerebral Oxygenation and Electrical Activity in Infants Born Preterm.

    Science.gov (United States)

    Dix, Laura Marie Louise; Weeke, Lauren Carleen; de Vries, Linda Simone; Groenendaal, Floris; Baerts, Willem; van Bel, Frank; Lemmers, Petra Maria Anna

    2017-08-01

    To evaluate the effects of acute arterial carbon dioxide partial pressure changes on cerebral oxygenation and electrical activity in infants born preterm. This retrospective observational study included ventilated infants born preterm with acute fluctuations of continuous end-tidal CO 2 (etCO 2 ) as a surrogate marker for arterial carbon dioxide partial pressure, during the first 72 hours of life. Regional cerebral oxygen saturation and fractional tissue oxygen extraction were monitored with near-infrared spectroscopy. Brain activity was monitored with 2-channel electroencephalography. Spontaneous activity transients (SATs) rate (SATs/minute) and interval between SATs (in seconds) were calculated. Ten-minute periods were selected for analysis: before, during, and after etCO 2 fluctuations of ≥5  mm Hg. Thirty-eight patients (mean ± SD gestational age of 29 ± 1.8 weeks) were included, with 60 episodes of etCO 2 increase and 70 episodes of etCO 2 decrease. During etCO 2 increases, brain oxygenation increased (regional cerebral oxygen saturation increased, fractional tissue oxygen extraction decreased; P carbon dioxide partial pressure that may be harmful to the neonatal brain. Copyright © 2017 Elsevier Inc. All rights reserved.

  14. Oxygen requirement of separated hybrid catfish eggs

    Science.gov (United States)

    Channel catfish egg masses require hatchery water with over 7.8 ppm dissolved oxygen at 80° F (95% air saturation) to maintain maximum oxygen consumption as they near hatching. This concentration is called the critical oxygen requirement by scientists but for the purpose of this article we will call...

  15. Sulfur Concentration at Sulfide Saturation in Anhydrous Silicate Melts at Crustal Conditions

    Science.gov (United States)

    Liu, Y.; Samaha, N.; Baker, D. R.

    2006-05-01

    The sulfur concentration in silicate melts at sulfide saturation (SCSS) was experimentally investigated in a temperature range from 1250°C to 1450°C and a pressure range from 500 MPa to 1 GPa in a piston-cylinder apparatus. The investigated melt compositions varied from rhyolitic to basaltic. All experiments were saturated with a FeS melt. Temperature was confirmed to have a positive effect on the SCSS and no measurable pressure effect was observed. Oxygen fugacity was controlled to be either near the carbon-carbon monoxide buffer or one log unit above the nickel-nickel oxide buffer, and found to positively affect the SCSS. A series of models were constructed to predict the SCSS as a function of temperature, pressure, melt composition, oxygen fugacity and sulfur fugacity of the system. The coefficients were obtained by the regression of experimental data from this study and from data in the literature. The best model found for the prediction of the SCSS is: ln S (ppm) = 996/T + 9.875 + 0.997 ln MFM + 0.1901 ln fO2 - 0.0722 (P/T) -0.115 ln f S2, where P is in bar, T is in K, and MFM is a compositional parameter describing the melt based upon cation mole fractions: MFM = [Na + K + 2 (Ca + Mg+ Fe2+)]/[Si × (Al + Fe3+)]. This model predicts the SCSS in anhydrous silicate melts from rhyolitic to basaltic compositions at crustal conditions from 1 bar to 1.25 GPa, temperatures from ~1200 to 1400 C, and oxygen fugacities between approximately two log units below the fayalite-quartz-magnetite buffer and one log unit above the nickel-nickel oxide buffer. For cases where the oxygen and sulfur fugacities can not be adequately estimated a simpler model also works acceptably: ln S (ppm) = -5328/T + 8.431 + 1.244 ln MFM - 0.01704(P/T) + ln aFeS, where aFeS is the activity of FeS in the sulfide melt and is well approximated by a value of 1. Additional experiments were performed on other basalts in a temperature range from 1250 C to 1450 C at 1 GPa to test the models. The model

  16. Prognostic value of brachioradialis muscle oxygen saturation index and vascular occlusion test in septic shock patients.

    Science.gov (United States)

    Marín-Corral, J; Claverias, L; Bodí, M; Pascual, S; Dubin, A; Gea, J; Rodriguez, A

    2016-05-01

    To compare rSO2 (muscle oxygen saturation index) static and dynamic variables obtained by NIRS (Near Infrared Spectroscopy) in brachioradialis muscle of septic shock patients and its prognostic implications. Prospective and observational study. Intensive care unit. Septic shock patients and healthy volunteers. The probe of a NIRS device (INVOS 5100) was placed on the brachioradialis muscle during a vascular occlusion test (VOT). Baseline, minimum and maximum rSO2 values, deoxygenation rate (DeOx), reoxygenation slope (ReOx) and delta value. Septic shock patients (n=35) had lower baseline rSO2 (63.8±12.2 vs. 69.3±3.3%, p<0.05), slower DeOx (-0.54±0.31 vs. -0.91±0.35%/s, p=0.001), slower ReOx (2.67±2.17 vs. 9.46±3.5%/s, p<0.001) and lower delta (3.25±5.71 vs. 15.1±3.9%, p<0.001) when compared to healthy subjects (n=20). Among septic shock patients, non-survivors showed lower baseline rSO2 (57.0±9.6 vs. 69.8±11.3%, p=0.001), lower minimum rSO2 (36.0±12.8 vs. 51.3±14.8%, p<0.01) and lower maximum rSO2 values (60.6±10.6 vs. 73.3±11.2%, p<0.01). Baseline rSO2 was a good mortality predictor (AUC 0.79; 95%CI: 0.63-0.94, p<0.01). Dynamic parameters obtained with VOT did not improve the results. Septic shock patients present an important alteration of microcirculation that can be evaluated by NIRS with prognostic implications. Monitoring microvascular reactivity in the brachioradialis muscle using VOT with our device does not seem to improve the prognostic value of baseline rSO2. Copyright © 2015 Elsevier España, S.L.U. and SEMICYUC. All rights reserved.

  17. Temperature effects on hemocyanin oxygen binding in an antarctic cephalopod.

    Science.gov (United States)

    Zielinski, S; Sartoris, F J; Pörtner, H O

    2001-02-01

    The functional relevance of oxygen transport by hemocyanin of the Antarctic octopod Megaleledone senoi and of the eurythermal cuttlefish Sepia officinalis was analyzed by continuous and simultaneous recordings of changes in pH and hemocyanin oxygen saturation in whole blood at various temperatures. These data were compared to literature data on other temperate and cold-water cephalopods (octopods and giant squid). In S. officinalis, the oxygen affinity of hemocyanin changed at deltaP50/degrees C = 0.12 kPa (pH 7.4) with increasing temperatures; this is similar to observations in temperate octopods. In M. senoi, thermal sensitivity was much smaller (delta log P50/delta pH) increased with increasing temperature in both the cuttlefish and the Antarctic octopod. At low PO2 (1.0 kPa) and pH (7.2), the presence of a large venous oxygen reserve (43% saturation) insensitive to pH reflects reduced pH sensitivity and high oxygen affinity in M. senoi hemocyanin at 0 degrees C. In S. officinalis, this reserve was 19% at pH 7.4, 20 degrees C, and 1.7 kPa O2, a level still higher than in squid. These findings suggest that the lower metabolic rate of octopods and cuttlefish compared to squid is reflected in less pH-dependent oxygen transport. Results of the hemocyanin analysis for the Antarctic octopod were similar to those reported for Vampyroteuthis--an extremely high oxygen affinity supporting a very low metabolic rate. In contrast to findings in cold-adapted giant squid, the minimized thermal sensitivity of oxygen transport in Antarctic octopods will reduce metabolic scope and thereby contribute to their stenothermality.

  18. Corrosion of low alloy steel containing 0.5% chromium in supercritical CO2-saturated brine and water-saturated supercritical CO2 environments

    Science.gov (United States)

    Wei, Liang; Gao, Kewei; Li, Qian

    2018-05-01

    The corrosion behavior of P110 low-Cr alloy steel in supercritical CO2-saturated brine (aqueous phase) and water-saturated supercritical CO2 (SC CO2 phase) was investigated. The results show that P110 steel primarily suffered general corrosion in the aqueous phase, while severe localized corrosion occurred in the SC CO2 phase. The formation of corrosion product scale on P110 steel in the aqueous phase divided into three stages: formation of the initial corrosion layer containing amorphous Cr(OH)3, FeCO3 and a small amount of Fe3C; transformation of initial corrosion layer to mixed layer, which consisted of FeCO3 and a small amount of Cr(OH)3 and Fe3C; growth and dissolution of the mixed layer. Finally, only a single mixed layer covered on the steel in the aqueous phase. However, the scale formed in SC CO2 phase consisted of two layers: the inner mixed layer and the dense outer FeCO3 crystalline layer.

  19. The oxygen-conserving potential of the diving response: A kinetic-based analysis.

    Science.gov (United States)

    Costalat, Guillaume; Coquart, Jeremy; Castres, Ingrid; Joulia, Fabrice; Sirost, Olivier; Clua, Eric; Lemaître, Frédéric

    2017-04-01

    We investigated the oxygen-conserving potential of the human diving response by comparing trained breath-hold divers (BHDs) to non-divers (NDs) during simulated dynamic breath-holding (BH). Changes in haemodynamics [heart rate (HR), stroke volume (SV), cardiac output (CO)] and peripheral muscle oxygenation [oxyhaemoglobin ([HbO 2 ]), deoxyhaemoglobin ([HHb]), total haemoglobin ([tHb]), tissue saturation index (TSI)] and peripheral oxygen saturation (SpO 2 ) were continuously recorded during simulated dynamic BH. BHDs showed a breaking point in HR kinetics at mid-BH immediately preceding a more pronounced drop in HR (-0.86 bpm.% -1 ) while HR kinetics in NDs steadily decreased throughout BH (-0.47 bpm.% -1 ). By contrast, SV remained unchanged during BH in both groups (all P > 0.05). Near-infrared spectroscopy (NIRS) results (mean ± SD) expressed as percentage changes from the initial values showed a lower [HHb] increase for BHDs than for NDs at the cessation of BH (+24.0 ± 10.1 vs. +39.2 ± 9.6%, respectively; P kinetic-based approach we used provides further credence to the concept of an "oxygen-conserving breaking point" in the human diving response.

  20. Measurement of brain oxygenation changes using dynamic T1-weighted imaging

    DEFF Research Database (Denmark)

    Haddock, Bryan; Larsson, Henrik B W; Hansen, Adam E

    2013-01-01

    Magnetic resonance imaging (MRI) has proven useful in evaluating oxygenation in several types of tissue and blood. This study evaluates brain tissue oxygenation changes between normoxia and hyperoxia in healthy subjects using dynamic T1 and T2*-weighted imaging sequences. The change in FiO2 induced...... by hyperoxia caused a significant decrease in T1. A model to determine changes in tissue oxygen tension from the T1-weighted MRI signal is presented based on previous findings that T1 is sensitive to oxygen tension whereas T2* is sensitive to blood saturation. The two sequences produce results with different...... regional and temporal dynamics. These differences combined with results from simulations of the T1 signal intensities, indicate an increase in extravascular oxygen tension during hyperoxia. This study concludes that T1 and T2* responses to FiO2 serve as independent biomarkers of oxygen physiology...

  1. Transport of Sr 2+ and SrEDTA 2- in partially-saturated and heterogeneous sediments

    Science.gov (United States)

    Pace, M. N.; Mayes, M. A.; Jardine, P. M.; McKay, L. D.; Yin, X. L.; Mehlhorn, T. L.; Liu, Q.; Gürleyük, H.

    2007-05-01

    Strontium-90 has migrated deep into the unsaturated subsurface beneath leaking storage tanks in the Waste Management Areas (WMA) at the U.S. Department of Energy's (DOE) Hanford Reservation. Faster than expected transport of contaminants in the vadose zone is typically attributed to either physical hydrologic processes such as development of preferential flow pathways, or to geochemical processes such as the formation of stable, anionic complexes with organic chelates, e.g., ethylenediaminetetraacetic acid (EDTA). The goal of this paper is to determine whether hydrological processes in the Hanford sediments can influence the geochemistry of the system and hence control transport of Sr 2+ and SrEDTA 2-. The study used batch isotherms, saturated packed column experiments, and an unsaturated transport experiment in an undisturbed core. Isotherms and repacked column experiments suggested that the SrEDTA 2- complex was unstable in the presence of Hanford sediments, resulting in dissociation and transport of Sr 2+ as a divalent cation. A decrease in sorption with increasing solid:solution ratio for Sr 2+ and SrEDTA 2- suggested mineral dissolution resulted in competition for sorption sites and the formation of stable aqueous complexes. This was confirmed by detection of MgEDTA 2-, MnEDTA 2-, PbEDTA 2-, and unidentified Sr and Ca complexes. Displacement of Sr 2+ through a partially-saturated undisturbed core resulted in less retardation and more irreversible sorption than was observed in the saturated repacked columns, and model results suggested a significant reservoir (49%) of immobile water was present during transport through the heterogeneous layered sediments. The undisturbed core was subsequently disassembled along distinct bedding planes and subjected to sequential extractions. Strontium was unequally distributed between carbonates (49%), ion exchange sites (37%), and the oxide (14%) fraction. An inverse relationship between mass wetness and Sr suggested that

  2. Calculation on the heat of gasification for the saturated liquid of D2

    International Nuclear Information System (INIS)

    Ge Fangfang; China Academy of Engineering Physics, Mianyang; Zhu Zhenghe; Wang Hongbin; Zhou Weimin; Chen Hao; Liu Hongjie

    2005-01-01

    In general, the saturated stream is regarded as the ideal gas for calculating the heat of gasification for the saturated liquid. However, the result of calculation was not consistent with the general law if D 2 was treated as the ideal gas under T c =38.34 K, the critical temperature. Considering the change of the volume from the liquid state to the gas state, this paper implored the Clapeyron differential equation and the equation of vapor-liquid equilibrium, and then obtained the heat of gasification and the entropy from 20 K to 38 K and the saturation curve. The method avoided regarding the saturate gas D 2 as the ideal gas and ignoring the volume change from the liquid state to the gas state, improving the calculation exactitude. (authors)

  3. Near-infrared spectroscopy for detection of vascular compromise in paediatric supracondylar fractures

    International Nuclear Information System (INIS)

    Skowno, Justin J; De Lima, Jonathan; Quick, Tom J; Carpenter, Eleanor C; Gibbons, Paul J; Little, David G

    2014-01-01

    Children suffering supracondylar fractures of the humerus are at risk of vascular compromise, which is currently assessed clinically, although other modalities such as angiography, pulse oximetry, Doppler ultrasound and magnetic resonance angiography have been used. We sought to ascertain whether tissue haemoglobin oxygenation (StO 2 ) measurement could distinguish between patients with and without clinical vascular compromise following supracondylar fractures of the humerus. We prospectively observed StO 2  using near-infrared spectroscopy in 29 paediatric patients with supracondylar fractures requiring operative manipulation. The injured and uninjured volar forearm compartments were monitored immediately before and after fracture reduction. The relationship between StO 2  in the injured and uninjured limb, and the presence of pre-operative vascular compromise was assessed. Seven out of 29 children presented with vascular compromise. Patients with clinical vascular compromise had significantly lower pre-reduction StO 2  (63.5% ± 15%, mean ± standard deviation), compared to those without compromise (80.9% ± 10%). StO 2  normalized following surgery in all children with vascular compromise. These improvements in muscle StO 2  were associated, in all patients, with the clinical return of pulses and resolution of neurological symptoms if present. StO 2  monitoring can identify patients with clinical vascular compromise, can identify the return of adequate perfusion following operative correction of supracondylar fractures, and may be a useful adjunct to clinical assessment. (paper)

  4. Milrinone, a phosphodiesterase III inhibitor, prevents reduction of jugular bulb saturation during rewarming from hypothermic cardiopulmonary bypass.

    Science.gov (United States)

    Iritakenishi, T; Hayashi, Y; Yamanaka, H; Kamibayashi, T; Ueda, K; Mashimo, T

    2012-01-01

    Inadequate cerebral oxygen balance during cardiopulmonary bypass may cause neuropsychological dysfunction. Milrinone, a phosphodiesterase III inhibitor, augments cerebral blood flow by direct vasodilatation. We conducted a prospective, randomized study in patients undergoing cardiac surgery with cardiopulmonary bypass to clarify the clinical efficacy of milrinone in the imbalance of cerebral oxygen supply and demand during the rewarming period of cardiopulmonary bypass. This is a prospective, randomized and placebo-controlled study. After anesthesia, a 5.5 F fiberoptic oximeter catheter was inserted into the right jugular bulb retrogradely for monitoring the jugular venous oxyhemoglobin saturation (SjO(2)). Patients were randomly assigned to two groups, one receiving a continuous infusion of milrinone, 0.5 µg/kg/min during hypothermic cardiopulmonary bypass, and the other receiving saline as control. Milrinone significantly prevented the reduction of the jugular venous oxyhemoglobin saturation at 10 minutes from the start of rewarming compared with the control group, but did not do so from 10 to 20 minutes after rewarming. Milrinone suppresses the reduction of SjO(2) and improves the balance of cerebral oxygen supply and demand during the early rewarming period of hypothermic cardiopulmonary bypass.

  5. Effect of gas-liquid-crystal transitions in oxygen clusters on electric and magnetic activity of localized states in In2O3-SrO ceramic

    Science.gov (United States)

    Okunev, V. D.; Szymczak, R.; Szymczak, H.; Aleshkevych, P.; Glot, A. B.; Bondarchuk, A. N.

    2015-10-01

    It has been shown that the overlap of tails of the density of states of the valence and conduction bands leads to the formation of a "negative" gap in the In2O3-SrO ceramic with disordered structure and oxygen clusters in nanovoids. Two types of magnetism are observed. One of them caused by the formation of (dangling bond + O- 2 center) complexes has been found in samples saturated with oxygen. The other is associated with the presence of dangling bonds in oxygen-depleted samples. At T conductivity of samples. The effects caused by magnetic phase transitions in clusters of crystal oxygen are manifested at T < 54.8 K. The variations of the resistance of samples in the interval T = 5-300 K correspond to Mott's law under the dependence of the local activation energy for electron hopping on the state of oxygen clusters.

  6. Electrochemical quartz crystal microbalance analysis of the oxygen reduction reaction on Pt-based electrodes. Part 2: adsorption of oxygen species and ClO4(-) anions on Pt and Pt-Co alloy in HClO4 solutions.

    Science.gov (United States)

    Omura, J; Yano, H; Tryk, D A; Watanabe, M; Uchida, H

    2014-01-14

    To gain deeper insight into the role of adsorbed oxygenated species in the O2 reduction reaction (ORR) kinetics on platinum and platinum-cobalt alloys for fuel cells, we carried out a series of measurements with the electrochemical quartz crystal microbalance (EQCM) and the rotating disk electrode (RDE) in acid solution. The effects of anion adsorption on the activities for the ORR were first assessed in HClO4 and HF electrolyte solutions at various concentrations. In our previous work (Part 1), we reported that the perchlorate anion adsorbs specifically on bulk-Pt, with a Frumkin-Temkin isotherm, that is, a linear relationship between Δm and log[HClO4]. Here, we find that the specific adsorption on the Pt-skin/Pt3Co alloy was significantly stronger than that on bulk-Pt, in line with its modified electronic properties. The kinetically controlled current density j(k) for the O2 reduction at the Pt-skin/Pt3Co-RDE was about 9 times larger than that of the bulk-Pt-RDE in 0.01 M HClO4 saturated with air, but the j(k) values on Pt-skin/Pt3Co decreased with increasing [HClO4] more steeply than in the case of Pt, due to the blocking of the active sites by the specifically adsorbed ClO4(-). We have detected reversible mass changes for one or more adsorbed oxygen-containing species (Ox = O2, O, OH, H2O) on the Pt-skin/Pt3Co-EQCM and Pt-EQCM in O2-saturated and He-purged 0.01 M HClO4 solutions, in which the specific adsorption of ClO4(-) anions was negligible. The coverages of oxygen species θ(Ox) on the Pt-skin/Pt3Co in the potential range from 0.86 to 0.96 V in the O2-saturated solution were found to be larger than those on pure Pt, providing strong evidence that the higher O2 reduction activity on the Pt3Co is correlated with higher θ(Ox), contrary to the conventional view.

  7. Effect of the surface oxygen groups on methane adsorption on coals

    Energy Technology Data Exchange (ETDEWEB)

    Hao Shixiong [Department of Chemical Engineering, Sichuan University, Chengdu 610065 (China); Department of Chemical Engineering, Sichuan University of Science and Engineering, Zigong 643000 (China); Wen Jie [Department of Chemical Engineering, Sichuan University, Chengdu 610065 (China); Yu Xiaopeng [Department of Chemical Engineering, Sichuan University, Chengdu 610065 (China); Department of Chemical Engineering, Sichuan University of Science and Engineering, Zigong 643000 (China); Chu Wei, E-mail: chuwei1965_scu@yahoo.com [Department of Chemical Engineering, Sichuan University, Chengdu 610065 (China)

    2013-01-01

    Highlights: Black-Right-Pointing-Pointer We modified one coal with H{sub 2}O{sub 2}, (NH{sub 4}){sub 2}S{sub 2}O{sub 8} and HNO{sub 3} respectively, to prepare coal samples with different surface properties. Black-Right-Pointing-Pointer The oxygen groups on coal surface were characterized by XPS. Black-Right-Pointing-Pointer The textures of the coal samples were investigated by N{sub 2} adsorption at 77 K. Black-Right-Pointing-Pointer The adsorption behaviors were measured by volumetric method. Black-Right-Pointing-Pointer There was a negative correlation between methane saturated adsorption capacity and the O{sub total}/C{sub total}. - Abstract: To investigate the influence of surface oxygen groups on methane adsorption on coals, one bituminous coal was modified with H{sub 2}O{sub 2}, (NH{sub 4}){sub 2}S{sub 2}O{sub 8} and HNO{sub 3} respectively, to prepare coal samples with different surface properties. The oxygen groups on coal surface were characterized by X-ray photoelectron spectroscopy (XPS). The textures of the coal samples were investigated by N{sub 2} adsorption at 77 K. Their surface morphologies were analyzed by scanning electron microscopy (SEM). The methane adsorption behaviors of these coal samples were measured at 303 K in pressure range of 0-5.3 MPa by volumetric method. The adsorption data of methane were fitted to the Langmuir model and Dubinin-Astakhov (D-A) model. The fitting results showed that the D-A model fitted the isotherm data better than the Langmuir model. It was observed that there was, in general, a positive correlation between the methane saturated adsorption capacity and the micropore volume of coals while a negative correlation between methane saturated adsorption capacity and the O{sub total}/C{sub total}. The methane adsorption capacity was determined by the coal surface chemistry when the microporosity parameters of two samples were similar. Coal with a higher amount of oxygen surface groups, and consequently with a less

  8. Cerebral and Renal Oxygen Saturation Are Not Compromised in the Presence of Retrograde Blood Flow in either the Ascending or Descending Aorta in Term or Near-Term Infants with Left-Sided Obstructive Lesions

    NARCIS (Netherlands)

    van der Laan, Michelle E.; Mebius, Mirthe J.; Roofthooft, Marcus T. R.; Bos, Arend F.; Berger, Rolf M. F.; Kooi, Elisabeth M. W.

    2017-01-01

    Background: In infants with left-sided obstructive lesions (LSOL), the presence of retrograde blood flow in either the ascending or descending aorta may lead to diminished cerebral and renal blood flow, respectively. Objectives: Our aim was to compare cerebral and renal tissue oxygen saturation

  9. Resistive switching behavior in single crystal SrTiO{sub 3} annealed by laser

    Energy Technology Data Exchange (ETDEWEB)

    Pan, Xinqiang [State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054 (China); Shuai, Yao, E-mail: yshuai@uestc.edu.cn [State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054 (China); Collaboration Innovation Center of Electronic Materials and Devices, University of Electronic Science and Technology of China, Chengdu 610054 (China); Wu, Chuangui, E-mail: cgwu@uestc.edu.cn [State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054 (China); Collaboration Innovation Center of Electronic Materials and Devices, University of Electronic Science and Technology of China, Chengdu 610054 (China); Luo, Wenbo [State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054 (China); Collaboration Innovation Center of Electronic Materials and Devices, University of Electronic Science and Technology of China, Chengdu 610054 (China); Sun, Xiangyu [State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054 (China); Yuan, Ye; Zhou, Shengqiang [Helmholtz-Zentrum Dresden Rossendorf, Institute of Ion Beam Physics and Materials Research, Bautzner Landstrasse 400, D-01328 Dresden (Germany); Ou, Xin [State Key Laboratory of Functional Material for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050 (China); Zhang, Wanli [State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054 (China); Collaboration Innovation Center of Electronic Materials and Devices, University of Electronic Science and Technology of China, Chengdu 610054 (China)

    2016-12-15

    Highlights: • Laser annealing was used to introduce oxygen vacancies into the single crystal SrTiO{sub 3}. • The effect of laser annealing with different fluence on the single crystal SrTiO{sub 3} was systematically studied. • The concentration of oxygen vacancies can be tuned by changing the fluence of laser. • Resistive switching behavior was observed in the sample with relatively high laser fluence after an electro-forming process. - Abstract: Single crystal SrTiO{sub 3} (STO) wafers were annealed by XeCl laser (λ = 308 nm) with different fluences of 0.4 J/cm{sup 2}, 0.6 J/cm{sup 2} and 0.8 J/cm{sup 2}, respectively. Ti/Pt electrodes were sputtered on the surface of STO wafer to form co-planar capacitor-like structures of Pt/Ti/STO/Ti/Pt. Current-Voltage measurements show that the leakage current is enhanced by increasing laser fluence. Resistive switching behavior is only observed in the sample annealed by laser with relatively high fluence after an electro-forming process. The X-ray photoelectron spectroscopy measurements indicate that the amount of oxygen vacancies increases with the increase of laser fluence. This work indicates resistive switching appears when enough oxygen vacancies are generated by the laser, which form conductive filaments under an external electric field.

  10. THERMAL AND OXYGEN CONDITIONS IN CARP PONDS DURING THE SUMMER PERIOD

    Directory of Open Access Journals (Sweden)

    Magdalena Wiśnios

    2015-11-01

    Full Text Available The work presents changes of oxygen indices in carp ponds during the summer season. The basis of the research were regular water tests conducted in two ponds: Mydlniki II intended for carp farming in the second year of fish production cycle and Bocian used for carp farming in the third (final year of breeding. The temperature of pond water in July and August was optimal for development and farming of cyprinid fish and ranged from 16.6 to 30.5 °C. The lowest value of oxygen dissolved in water (6.4 mg·dm-3 was registered in Mydlniki II pond and was higher than the oxygen optimum for carp (5 mg·dm-3. Oxygen saturation in water of fish ponds exceeded the optimum upper limit value (168% on a few dates, however, it posed no lethal threat for fish. In August in Bocian pond oxygen saturation fell within the range of optimal values, creating better conditions for fish development. In the secondary pond (Mydlniki II it was found that oxygen saturation in water on 12 dates was lower than the low optimal value (96%.

  11. Healthy Dental Pulp Oxygen Saturation Rates in Subjects with Homozygous Sickle Cell Anemia: A Cross-Sectional Study Nested in a Cohort.

    Science.gov (United States)

    Souza, Soraia de Fátima Carvalho; Thomaz, Erika Bárbara Abreu Fonseca; Costa, Cyrene Piazera Silva

    2017-12-01

    To compare the percentage of arterial oxygen saturation (SpO 2 ) in healthy teeth with confirmed pulp vitality between individuals with sickle cell anemia (HbSS) and normal hemoglobin A (HbAA). This is a cross-sectional study nested within a cohort. Samples (n = 2543) comprised teeth with intact crowns and pulp vitality confirmed by thermal sensitivity tests and no history of caries, periodontal disease, or dental trauma. A total of 728 teeth of 113 individuals with HbSS and 1815 teeth of 246 individuals with HbAA were evaluated. Data analysis was performed using the χ 2 and Mann-Whitney tests and Spearman correlation analysis (α = 0.05). The study groups were comparable in terms of age, race, and sex (P > .05). Subjects with HbSS exhibited lower median SpO 2 levels in the body and upper teeth, excluding canines, than subjects with HbAA (P  .05). Compared with individuals with HbAA, those with HbSS exhibited lower SpO 2 in maxillary teeth with confirmed pulp vitality, except in the canines. There was no correlation between SpO 2 levels of the body and dental pulp in individuals with HbSS or HbAA. Copyright © 2017 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  12. Carbon dioxide narcosis due to inappropriate oxygen delivery: a case report.

    Science.gov (United States)

    Herren, Thomas; Achermann, Eva; Hegi, Thomas; Reber, Adrian; Stäubli, Max

    2017-07-28

    Oxygen delivery to patients with chronic obstructive pulmonary disease may be challenging because of their potential hypoxic ventilatory drive. However, some oxygen delivery systems such as non-rebreathing face masks with an oxygen reservoir bag require high oxygen flow for adequate oxygenation and to avoid carbon dioxide rebreathing. A 72-year-old Caucasian man with severe chronic obstructive pulmonary disease was admitted to the emergency department because of worsening dyspnea and an oxygen saturation of 81% measured by pulse oximetry. Oxygen was administered using a non-rebreathing mask with an oxygen reservoir bag attached. For fear of removing the hypoxic stimulus to respiration the oxygen flow was inappropriately limited to 4L/minute. The patient developed carbon dioxide narcosis and had to be intubated and mechanically ventilated. Non-rebreathing masks with oxygen reservoir bags must be fed with an oxygen flow exceeding the patient's minute ventilation (>6-10 L/minute.). If not, the amount of oxygen delivered will be too small to effectively increase the arterial oxygen saturation. Moreover, the risk of carbon dioxide rebreathing dramatically increases if the flow of oxygen to a non-rebreathing mask is lower than the minute ventilation, especially in patients with chronic obstructive pulmonary disease and low tidal volumes. Non-rebreathing masks (with oxygen reservoir bags) must be used cautiously by experienced medical staff and with an appropriately high oxygen flow of 10-15 L/minute. Nevertheless, arterial blood gases must be analyzed regularly for early detection of a rise in partial pressure of carbon dioxide in arterial blood in patients with chronic obstructive pulmonary disease and a hypoxic ventilatory drive. These patients are more safely managed using a nasal cannula with an oxygen flow of 1-2L/minute or a simple face mask with an oxygen flow of 5L/minute.

  13. Quasi-two-dimensional electron gas at the interface of γ-Al{sub 2}O{sub 3}/SrTiO{sub 3} heterostructures grown by atomic layer deposition

    Energy Technology Data Exchange (ETDEWEB)

    Ngo, Thong Q.; McDaniel, Martin D.; Ekerdt, John G., E-mail: ekerdt@che.utexas.edu [Department of Chemical Engineering, University of Texas at Austin, Austin, Texas 78712 (United States); Goble, Nicholas J.; Gao, Xuan P. A. [Department of Physics, Case Western Reserve University, Cleveland, Ohio 44106 (United States); Posadas, Agham; Kormondy, Kristy J.; Demkov, Alexander A. [Department of Physics, University of Texas at Austin, Austin, Texas 78712 (United States); Lu, Sirong [School of Engineering for Matter, Transport and Engineering, Arizona State University, Tempe, Arizona 85287 (United States); Jordan-Sweet, Jean [IBM T.J. Watson Research Center, Yorktown Heights, New York 10598 (United States); Smith, David J. [Department of Physics, Arizona State University, Tempe, Arizona 85287 (United States)

    2015-09-21

    We report the formation of a quasi-two-dimensional electron gas (2-DEG) at the interface of γ-Al{sub 2}O{sub 3}/TiO{sub 2}-terminated SrTiO{sub 3} (STO) grown by atomic layer deposition (ALD). The ALD growth of Al{sub 2}O{sub 3} on STO(001) single crystal substrates was performed at temperatures in the range of 200–345 °C. Trimethylaluminum and water were used as co-reactants. In situ reflection high energy electron diffraction, ex situ x-ray diffraction, and ex situ cross-sectional transmission electron microscopy were used to determine the crystallinity of the Al{sub 2}O{sub 3} films. As-deposited Al{sub 2}O{sub 3} films grown above 300 °C were crystalline with the γ-Al{sub 2}O{sub 3} phase. In situ x-ray photoelectron spectroscopy was used to characterize the Al{sub 2}O{sub 3}/STO interface, indicating that a Ti{sup 3+} feature in the Ti 2p spectrum of STO was formed after 2–3 ALD cycles of Al{sub 2}O{sub 3} at 345 °C and even after the exposure to trimethylaluminum alone at 300 and 345 °C. The interface quasi-2-DEG is metallic and exhibits mobility values of ∼4 and 3000 cm{sup 2} V{sup −1} s{sup −1} at room temperature and 15 K, respectively. The interfacial conductivity depended on the thickness of the Al{sub 2}O{sub 3} layer. The Ti{sup 3+} signal originated from the near-interfacial region and vanished after annealing in an oxygen environment.

  14. Saturated Switching Systems

    CERN Document Server

    Benzaouia, Abdellah

    2012-01-01

    Saturated Switching Systems treats the problem of actuator saturation, inherent in all dynamical systems by using two approaches: positive invariance in which the controller is designed to work within a region of non-saturating linear behaviour; and saturation technique which allows saturation but guarantees asymptotic stability. The results obtained are extended from the linear systems in which they were first developed to switching systems with uncertainties, 2D switching systems, switching systems with Markovian jumping and switching systems of the Takagi-Sugeno type. The text represents a thoroughly referenced distillation of results obtained in this field during the last decade. The selected tool for analysis and design of stabilizing controllers is based on multiple Lyapunov functions and linear matrix inequalities. All the results are illustrated with numerical examples and figures many of them being modelled using MATLAB®. Saturated Switching Systems will be of interest to academic researchers in con...

  15. Detection of haemoglobins with abnormal oxygen affinity by single blood gas analysis and 2,3-diphosphoglycerate measurement.

    Science.gov (United States)

    Guerrini, G; Morabito, A; Samaja, M

    2000-10-01

    The aim is to determine if a single measurement of blood 2,3-diphosphoglycerate combined with gas analysis (pH, PCO2, PO2 and saturation) can identify the cause of an altered blood-oxygen affinity: the presence of an abnormal haemoglobin or a red cell disorder. The population (n=94) was divided into healthy controls (A, n=14), carriers of red cell disorders (B, n=72) and carriers of high oxygen affinity haemoglobins (C, n=8). Those variables were measured both in samples equilibrated at selected PCO2 and PO2 and in venous blood. In the univariable approach applied to equilibrated samples, we correctly identified C subjects in 93.6% or 96.8% of the cases depending on the selected variable, the standard P50 (PO2 at which 50% of haemoglobin is oxygenated) or a composite variable calculated from the above measurements. After introducing the haemoglobin concentration as a further discriminating variable, the A and B subjects were correctly identified in 91.9% or 94.2% of the cases, respectively. These figures become 93.0% or 86.1%, and 93.7% or 94.9% of the cases when using direct readings from venous blood, thereby avoiding the blood equilibration step. This test is feasible also in blood samples stored at 4 degrees C for 48 h, or at room temperature for 8 h.

  16. A brief clinical case of monitoring of oxygenator performance and patient-machine interdependency during prolonged veno-venous extracorporeal membrane oxygenation.

    Science.gov (United States)

    Belliato, Mirko; Degani, Antonella; Buffa, Antonino; Sciutti, Fabio; Pagani, Michele; Pellegrini, Carlo; Iotti, Giorgio Antonio

    2017-10-01

    Monitoring veno-venous extracorporeal membrane oxygenation (vvECMO) during 76 days of continuous support in a 42-years old patient with end-stage pulmonary disease, listed for double-lung transplantation. Applying a new monitor (Landing ® , Eurosets, Medolla, Italy) and describing how measured and calculated parameters can be used to understand the variable interdependency between artificial membrane lung (ML) and patient native lung (NL). During vvECMO, in order to understand how the respiratory function is shared between ML and NL, ideally we should obtain data about oxygen transfer and CO 2 removal, both by ML and NL. Measurements for NL can be made on the mechanical ventilator. Measurements for ML are typically made from gas analysis on blood samples drawn from the ECMO system before and after the oxygenator, and therefore are non-continuous. Differently, the Landing monitor provides a continuous measurement of the oxygen transfer from the ML, combined with hemoglobin level, saturation of drained blood and saturation of reinfused blood. Moreover, the Landing monitor provides hemodynamics data about circulation through the ECMO system, with blood flow, pre-oxygenator pressure and post-oxygenator pressure. Of note, measurements include the drain negative pressure, whose monitoring may be particularly useful to prevent hemolysis. Real-time monitoring of vvECMO provides data helpful to understand the complex picture of a patient with severely damaged lungs on one side and an artificial lung on the other side. Data from vvECMO monitoring may help to adapt the settings of both mechanical ventilator and vvECMO. Data about oxygen transfer by the oxygenator are important to evaluate the performance of the device and may help to avoid unnecessary replacements, thus reducing risks and costs.

  17. Tuning the electronic properties of LaAlO3/SrTiO3 interfaces by irradiating the LaAlO3 surface with low-energy cluster ion beams

    Science.gov (United States)

    Ridier, Karl; Aureau, Damien; Bérini, Bruno; Dumont, Yves; Keller, Niels; Vigneron, Jackie; Etcheberry, Arnaud; Domengès, Bernadette; Fouchet, Arnaud

    2018-01-01

    We have investigated the effects of low-energy ion beam irradiations using argon clusters on the chemical and electronic properties of LaAlO3/SrTiO3 (LAO/STO) heterointerfaces by combining x-ray photoelectron spectroscopy (XPS) and electrical transport measurements. Due to its unique features, we demonstrate that a short-time cluster ion irradiation of the LAO surface induces significant modifications in the chemical properties of the buried STO substrate with (1) a lowering of Ti atoms oxidation states (from Ti4 + to Ti3 + and Ti2 +) correlated to the formation of oxygen vacancies at the LAO surface and (2) the creation of new surface states for Sr atoms. Contrary to what is generally observed by using higher energy ion beam techniques, this leads to an increase of the electrical conductivity at the LAO/STO interface. Our XPS data clearly reveal the existence of dynamical processes on the titanium and strontium atoms, which compete with the effect of the cluster ion beam irradiation. These relaxation effects are in part attributed to the diffusion of the ion-induced oxygen vacancies in the entire heterostructure since an increase of the interfacial metallicity is also evidenced far from the irradiated area. This paper highlights the possibility of tuning the electrical properties of LAO/STO interfaces by surface engineering, confirming experimentally the intimate connection between LAO chemistry and electronic properties of LAO/STO interfaces.

  18. 31P nuclear magnetic resonance spectroscopy studies of tumor energy metabolism and its relationship to intracapillary oxyhemoglobin saturation status and tumor hypoxia.

    Science.gov (United States)

    Rofstad, E K; DeMuth, P; Fenton, B M; Sutherland, R M

    1988-10-01

    Relationships between tumor bioenergetic status on the one hand and intracapillary oxyhemoglobin (HbO2) saturation status and fraction of radiobiologically hypoxic cells on the other were studied using two murine sarcoma lines (KHT, RIF-1) and two human ovarian carcinoma xenograft lines (MLS, OWI). Tumor energy metabolism was studied in vivo by 31P nuclear magnetic resonance (NMR) spectroscopy and the resonance area ratio (PCr + NTP beta)/Pi was used as parameter for bioenergetic status. Intracapillary HbO2 saturation status reflects the oxygen supply conditions in tumors and was measured in vitro using a cryospectrophotometric method. The KHT, RIF-1, and MLS lines showed decreasing bioenergetic status, i.e., decreasing PCr and NTP beta resonances and an increasing Pi resonance, with increasing tumor volume, whereas the OWI line showed no changes in these resonances during tumor growth. The volume-dependence of the HbO2 saturation status differed similarly among the tumor lines; HbO2 saturation status decreased with increasing tumor volume for the KHT, RIF-1, and MLS lines and was independent of tumor volume for the OWI line. Moreover, linear correlations were found between bioenergetic status and HbO2 saturation status for individual tumors of the KHT, RIF-1, and MLS lines. These observations together indicated a direct relationship between 31P-NMR spectral parameters and tumor oxygen supply conditions. However, this relationship was not identical for the different tumor lines, suggesting that it was influenced by intrinsic properties of the tumor cells such as rate of respiration and ability to survive under hypoxia. Similarly, there was no correlation between bioenergetic status and fraction of radiobiologically hypoxic cells across the four tumor lines. This indicates that 31P-NMR spectroscopy data have to be supplemented with other data, e.g., rate of oxygen consumption, cell survival time under hypoxic stress, and/or fraction of metabolically active

  19. Stable isotopes of authigenic minerals in variably-saturated fractured tuff

    International Nuclear Information System (INIS)

    Weber, D.S.; Evans, D.D.

    1988-11-01

    Identifying stable isotope variation and mineralogical changes in fractured rock may help establish the history of climatic and geomorphological processes that might affect the isolation properties of a waste repository site. This study examines the use of the stable isotope ratios of oxygen ( 18 O/ 16 O) and carbon ( 13 C/ 12 C) in authigenic minerals as hydrogeochemical tools tracing low-temperature rock-water interaction in variably-saturated fractured stuff. Isotopic compositions of fracture-filling and rock matrix minerals in the Apache Leap tuff, near Superior, Arizona were concordant with geothermal temperatures and in equilibrium with water isotopically similar to present-day meteoric water and groundwater. Oxygen and carbon isotope ratios of fracture-filling, in unsaturated fractured tuff, displayed an isotopic gradient believed to result from near-surface isotopic enrichment due to evaporation rather than the effects of rock-water interaction. Oxygen isotope ratios of rock matrix opal samples exhibited an isotopic gradient believed to result from, leaching and reprecipitation of silica at depth. Methods and results can be used to further define primary flowpaths and the movement of water in variably-saturated fractured rock. 71 refs., 23 figs., 3 tabs

  20. Stable isotopes of authigenic minerals in variably-saturated fractured tuff

    Energy Technology Data Exchange (ETDEWEB)

    Weber, D.S.; Evans, D.D.

    1988-11-01

    Identifying stable isotope variation and mineralogical changes in fractured rock may help establish the history of climatic and geomorphological processes that might affect the isolation properties of a waste repository site. This study examines the use of the stable isotope ratios of oxygen ({sup 18}O/{sup 16}O) and carbon ({sup 13}C/{sup 12}C) in authigenic minerals as hydrogeochemical tools tracing low-temperature rock-water interaction in variably-saturated fractured stuff. Isotopic compositions of fracture-filling and rock matrix minerals in the Apache Leap tuff, near Superior, Arizona were concordant with geothermal temperatures and in equilibrium with water isotopically similar to present-day meteoric water and groundwater. Oxygen and carbon isotope ratios of fracture-filling, in unsaturated fractured tuff, displayed an isotopic gradient believed to result from near-surface isotopic enrichment due to evaporation rather than the effects of rock-water interaction. Oxygen isotope ratios of rock matrix opal samples exhibited an isotopic gradient believed to result from, leaching and reprecipitation of silica at depth. Methods and results can be used to further define primary flowpaths and the movement of water in variably-saturated fractured rock. 71 refs., 23 figs., 3 tabs.

  1. A new through-tubing oil-saturation measurement system

    International Nuclear Information System (INIS)

    Roscoe, B.A.; Adolph, R.A.; Bontemy, Y.; Cheeseborough, J.C. III; Hall, J.S.; McKeon, D.C.; Pittman, D.; Seeman, B.; Thomas, S.R. Jr.

    1991-01-01

    This paper reports on carbon-oxygen logging which is used primarily to estimate oil saturation in cased-hole conditions when the formation water is fresh or unknown. The drawbacks of current techniques are: slow logging speed, large tool diameter, and excessive sensitivity to borehole fluid composition. A new, slim, neutron-induced gamma ray spectroscopy logging system has been developed to overcome some of these limitations. The new logging service is called the Reservoir Saturation (RST) Tool. Initial field tests are being carried out in the Middle East. The RST tool uses multiple detectors to separate the signal contributions from the borehole and the formation. Therefore, even when the borehole fluid composition is unknown, oil saturation can be determined in addition to the borehole oil fraction. This presents the possibility of logging flowing wells, which ensures that reinvasion and crossflow will not affect the results, and eliminates the costs of well preparation

  2. Combining central venous-to-arterial partial pressure of carbon dioxide difference and central venous oxygen saturation to guide resuscitation in septic shock.

    Science.gov (United States)

    Du, Wei; Liu, Da-Wei; Wang, Xiao-Ting; Long, Yun; Chai, Wen-Zhao; Zhou, Xiang; Rui, Xi

    2013-12-01

    Central venous oxygen saturation (Scvo2) is a useful therapeutic target when treating septic shock. We hypothesized that combining Scvo2 and central venous-to-arterial partial pressure of carbon dioxide difference (△Pco2) may provide additional information about survival. We performed a retrospective analysis of 172 patients treated for septic shock. All patients were treated using goal-directed therapy to achieve Scvo2 ≥ 70%. After 6 hours of treatment, we divided patients into 4 groups based on Scvo2 (<70% or ≥ 70%) and △Pco2 (<6 mm Hg or ≥ 6 mm Hg). Overall, 28-day mortality was 35.5%. For patients in whom the Scvo2 target was not achieved at 6 hours, mortality was 50.0%, compared with 29.5% in those in whom Scvo2 exceeded 70% (P = .009). In patients with Scvo2 ≥ 70%, mortality was lower if △Pco2 was <6 mm Hg than if △Pco2 was ≥ 6 mm Hg (56.1% vs 16.1%, respectively; P < .001) and 6-hour lactate clearance was superior (0.01 ± 0.61 vs 0.21 ± 0.31, respectively; P = .016). The combination of Scvo2 and △Pco2 appears to predict outcome in critically ill patients resuscitated from septic shock better than Scvo2 alone. Patients who meet both targets appear to clear lactate more efficiently. © 2013.

  3. Growth and Properties of Oxygen and Ion Doped BISMUTH(2) STRONTIUM(2) Calcium COPPER(2) Oxygen (8+DELTA) Single Crystals

    Science.gov (United States)

    Mitzi, David Brian

    1990-01-01

    A directional solidification method for growing large single crystals in the Bi_2Sr _2CaCu_2O _{8+delta} system is reported. Ion substitutions, with replacement of La for Sr and Y for Ca, as well as oxygen doping in these crystals has been explored. Ion doping results in little change of the superconducting transition for substitution levels below 20-25% (as a result of simultaneous oxygen intercalation), while beyond this level, the Meissner signal broadens and the low temperature Meissner signal decreases. Microprobe analysis and x-ray diffraction performed on these more highly substituted single crystals, provides evidence for inhomogeneity and phase segregation into regions of distinct composition. Annealing unsubstituted crystals in increasing partial pressures of oxygen reversibly depresses the superconducting transition temperature from 90K (as made) to 77K (oxygen pressure annealed) while the Hall concentrations increase from n = 3.1(3) times 10 ^{21} cm^{ -3} (0.34 holes/Cu site) to 4.6(3) times 10^{21} cm^{-3} (0.50 holes/Cu site). Further suppression of T_{c} to 72K is possible by annealing in oxygen pressures up to 100atm. No degradation of the Meissner transition or other indications of inhomogeneity or phase segregation with doping are noted, suggesting that oxygen doped Bi_2Sr _2CaCu_2O _{8+delta} is a suitable system for pursuing doping studies. The decrease in T _{c} with concentration for 0.34 <=q n <=q 0.50 indicates that a high carrier concentration regime exists where T_{c} decreases with n and suggests that this decrease does not arise from material inhomogeneity or other materials problems. The physical properties of these Bi _2Sr_2CaCu _2O_{8+delta} crystals, in this high carrier concentration regime, will be discussed.

  4. Correlation of oxygenation and perfusion sensitive MRI with invasive micro probe measurements in healthy mice brain

    International Nuclear Information System (INIS)

    Sedlacik, Jan; Fiehler, Jens; Reitz, Matthias; Schmidt, Nils O.; Bolar, Divya S.; Adalsteinsson, Elfar

    2015-01-01

    The non-invasive assessment of (patho-)physiological parameters such as, perfusion and oxygenation, is of great importance for the characterization of pathologies e.g., tumors, which may be helpful to better predict treatment response and potential outcome. To better understand the influence of physiological parameters on the investigated oxygenation and perfusion sensitive MRI methods, MRI measurements were correlated with subsequent invasive micro probe measurements during free breathing conditions of air, air+10% CO2 and 100% O2 in healthy mice brain. MRI parameters were the irreversible (R2), reversible (R2') and effective (R2*) transverse relaxation rates, venous blood oxygenation level assessed by quantitative blood oxygenation level dependent (qBOLD) method and cerebral blood flow (CBF) assessed by arterial spin labeling (ASL) using a 7T small animal MRI scanner. One to two days after MRI, tissue perfusion and pO2 were measured by Laser-Doppler flowmetry and fluorescence quenching micro probes, respectively. The tissue pO2 values were converted to blood oxygen saturation by using the Hill equation. The animals were anesthetized by intra peritoneal injection of ketamine-xylazine-acepromazine (10-2-0.3 mg/ml.kg). Results for normal/hypercapnia/hyperoxia conditions were: R2[s and -1] = 20.7/20.4/20.1, R2*[s and -1] = 31.6/29.6/25.9, R2'[s and 1] = 10.9/9.2/5.7, qBOLD venous blood oxygenation level = 0.43/0.51/0.56, CBF[ml.min and -1.100g and -1] = 70.6/105.5/81.8, Laser-Doppler flowmetry[a.u.] = 89.2/120.2/90.6 and pO2[mmHg] = 6.3/32.3/46.7. All parameters were statistically significantly different with P < 0.001 between all breathing conditions. All MRI and the corresponding micro probe measurements were also statistically significantly (P ≤ 0.03) correlated with each other. However, converting the tissue pO2 to blood oxygen saturation = 0.02/0.34/0.63, showed only very limited agreement with the qBOLD venous blood oxygenation level. We found good

  5. Correlation of oxygenation and perfusion sensitive MRI with invasive micro probe measurements in healthy mice brain

    Energy Technology Data Exchange (ETDEWEB)

    Sedlacik, Jan; Fiehler, Jens [University Medical Center Hamburg-Eppendorf, Hamburg (Germany). Neuroradiology; Reitz, Matthias; Schmidt, Nils O. [University Medical Center Hamburg-Eppendorf, Hamburg (Germany). Neurosurgery; Bolar, Divya S. [Massachusetts General Hospital, Athinoula A. Martinos Center for Biomedical Imaging, Charlestown, MA (United States). Radiology; Adalsteinsson, Elfar [Massachusetts Institute of Technology, Cambridge, MA (United States). Electrical Engineering and Computer Science

    2015-05-01

    The non-invasive assessment of (patho-)physiological parameters such as, perfusion and oxygenation, is of great importance for the characterization of pathologies e.g., tumors, which may be helpful to better predict treatment response and potential outcome. To better understand the influence of physiological parameters on the investigated oxygenation and perfusion sensitive MRI methods, MRI measurements were correlated with subsequent invasive micro probe measurements during free breathing conditions of air, air+10% CO2 and 100% O2 in healthy mice brain. MRI parameters were the irreversible (R2), reversible (R2') and effective (R2*) transverse relaxation rates, venous blood oxygenation level assessed by quantitative blood oxygenation level dependent (qBOLD) method and cerebral blood flow (CBF) assessed by arterial spin labeling (ASL) using a 7T small animal MRI scanner. One to two days after MRI, tissue perfusion and pO2 were measured by Laser-Doppler flowmetry and fluorescence quenching micro probes, respectively. The tissue pO2 values were converted to blood oxygen saturation by using the Hill equation. The animals were anesthetized by intra peritoneal injection of ketamine-xylazine-acepromazine (10-2-0.3 mg/ml.kg). Results for normal/hypercapnia/hyperoxia conditions were: R2[s {sup and} -1] = 20.7/20.4/20.1, R2*[s {sup and} -1] = 31.6/29.6/25.9, R2'[s {sup and} 1] = 10.9/9.2/5.7, qBOLD venous blood oxygenation level = 0.43/0.51/0.56, CBF[ml.min {sup and} -1.100g {sup and} -1] = 70.6/105.5/81.8, Laser-Doppler flowmetry[a.u.] = 89.2/120.2/90.6 and pO2[mmHg] = 6.3/32.3/46.7. All parameters were statistically significantly different with P < 0.001 between all breathing conditions. All MRI and the corresponding micro probe measurements were also statistically significantly (P ≤ 0.03) correlated with each other. However, converting the tissue pO2 to blood oxygen saturation = 0.02/0.34/0.63, showed only very limited agreement with the qBOLD venous blood

  6. Oxygen effect on the electrical characteristics of pentacene transistors

    International Nuclear Information System (INIS)

    Hu Yan; Dong Guifang; Hu Yuanchuan; Wang Liduo; Qiu Yong

    2006-01-01

    The effect of oxygen on the electrical characteristics of organic thin film transistors with pentacene as the active layer has been investigated. The saturation currents and mobilities of the transistors increase as the ambient oxygen concentration decreases, which is ascribed to the formation of a charge transfer complex between pentacene and O 2 . The deposition rate of the pentacene layer affects this phenomenon. The transistor with the pentacene layer deposited at a rate of 15 nm min -1 shows higher sensitivity to oxygen concentration than the device with the pentacene layer deposited at 30 nm min -1 . We suggest that when deposited at a lower rate the pentacene film is less compact, leading to easier entrance of oxygen into the charge accumulation region

  7. Studies of non-isothermal flow in saturated and partially saturated porous media

    International Nuclear Information System (INIS)

    Ho, C.K.; Maki, K.S.; Glass, R.J.

    1993-01-01

    Physical and numerical experiments have been performed to investigate the behavior of nonisothermal flow in two-dimensional saturated and partially saturated porous media. The physical experiments were performed to identify non-isothermal flow fields and temperature distributions in fully saturated, half-saturated, and residually saturated two-dimensional porous media with bottom heating and top cooling. Two counter-rotating liquid-phase convective cells were observed to develop in the saturated regions of all three cases. Gas-phase convection was also evidenced in the unsaturated regions of the partially saturated experiments. TOUGH2 numerical simulations of the saturated case were found to be strongly dependent on the assumed boundary conditions of the physical system. Models including heat losses through the boundaries of the test cell produced temperature and flow fields that were in better agreement with the observed temperature and flow fields than models that assumed insulated boundary conditions. A sensitivity analysis also showed that a reduction of the bulk permeability of the porous media in the numerical simulations depressed the effects of convection, flattening the temperature profiles across the test cell

  8. A high-resolution non-invasive approach to quantify oxygen transport across the capillary fringe and within the underlying groundwater.

    Science.gov (United States)

    Haberer, Christina M; Rolle, Massimo; Liu, Sanheng; Cirpka, Olaf A; Grathwohl, Peter

    2011-03-25

    Oxygen transport across the capillary fringe is relevant for many biogeochemical processes. We present a non-invasive technique, based on optode technology, to measure high-resolution concentration profiles of oxygen across the unsaturated/saturated interface. By conducting a series of quasi two-dimensional flow-through laboratory experiments, we show that vertical hydrodynamic dispersion in the water-saturated part of the capillary fringe is the process limiting the mass transfer of oxygen. A number of experimental conditions were tested in order to investigate the influence of grain size and horizontal flow velocity on transverse vertical dispersion in the capillary fringe. In the same setup, analogous experiments were simultaneously carried out in the fully water-saturated zone, therefore allowing a direct comparison with oxygen transfer across the capillary fringe. The outcomes of the experiments under various conditions show that oxygen transport in the two zones of interest (i.e., the unsaturated/saturated interface and the saturated zone) is characterized by very similar transverse dispersion coefficients. An influence of the capillary fringe morphology on oxygen transport has not been observed. These results may be explained by the narrow grain size distribution used in the experiments, leading to a steep decline in water saturation at the unsaturated/saturated interface and to the absence of trapped gas in this transition zone. We also modeled flow (applying the van Genuchten and the Brooks-Corey relationships) and two-dimensional transport across the capillary fringe, obtaining simulated profiles of equivalent aqueous oxygen concentration that were in good agreement with the observations. Copyright © 2010 Elsevier B.V. All rights reserved.

  9. Intramyocardial oxygen transport by quantitative diffuse reflectance spectroscopy in calves

    Science.gov (United States)

    Lindbergh, Tobias; Larsson, Marcus; Szabó, Zoltán; Casimir-Ahn, Henrik; Strömberg, Tomas

    2010-03-01

    Intramyocardial oxygen transport was assessed during open-chest surgery in calves by diffuse reflectance spectroscopy using a small intramuscular fiber-optic probe. The sum of hemo- and myoglobin tissue fraction and oxygen saturation, the tissue fraction and oxidation of cytochrome aa3, and the tissue fraction of methemoglobin were estimated using a calibrated empirical light transport model. Increasing the oxygen content in the inhaled gas, 21%-50%-100%, in five calves (group A) gave an increasing oxygen saturation of 19+/-4%, 24+/-5%, and 28+/-8% (panimals increased with LVAD pump speed (p<0.001, ANOVA) and with oxygen content in inhaled gas (p<0.001, ANOVA). The cytochrome aa3 oxidation level was above 96% in both group A and group B calves, including the two cases involving cardiac arrest. In conclusion, the estimated tissue fractions and oxygenation/oxidation levels of the myocardial chromophores during respiratory and hemodynamic provocations were in agreement with previously presented results, demonstrating the potential of the method.

  10. Design of a tissue oxygenation monitor and verification on human skin

    Science.gov (United States)

    Liu, Hongyuan; Kohl-Bareis, Matthias; Huang, Xiabing

    2011-07-01

    We report the design of a tissue oxygen and temperature monitor. The non-invasive, fibre based device monitors tissue haemoglobin (Hb) and oxygen saturation (SO2) and is based on white-light reflectance spectroscopy.Visible light with wavelengths in the 500 - 650nm range is utilized. The spectroscopic algorithm takes into account the tissue scattering and melanin absorption for the calculation of tissue haemoglobin concentration and oxygen saturation. The monitor can probe superficial layers of tissue with a high spatial resolution (mm3) and a high temporal resolution (40 Hz). It provides an accurate measurement with the accuracy of SO2 at 2 % and high reliability with less than 2 % variation of continuous SO2 measurement over 12 hours. It can also form a modular system when used in conjunction with a laser Doppler monitor, enabling simultaneous measurements of Hb, SO2 and blood flow. We found experimentally that the influence of the source-detector separation on the haemoglobin parameters is small. This finding is discussed by Monte Carlo simulations for the depth sensitivity profile. The influence of probe pressure and the skin pigmentation on the measurement parameters are assessed before in vivo experimental data is presented. The combination with laser Doppler flowmetry demonstrates the importance of a measurement of both the haemoglobin and the blood flow parameters for a full description of blood tissue perfusion. This is discussed in experimental data on human skin during cuff occlusion and after hyperemisation by a pharmacological cream. Strong correlation is observed between tissue oxygen (Hb and SO2) and blood flow measurements.

  11. Hypoxemia Episodes during Day and Night and Their Impact on Oxygen Saturation Targeting in Mechanically Ventilated Preterm Infants.

    Science.gov (United States)

    Jain, Deepak; D'Ugard, Carmen; Bello, Jose; Bancalari, Eduardo; Claure, Nelson

    2018-01-01

    Hypoxemia episodes (HE) occur frequently in ventilated preterm infants and hinder the achievement of arterial oxygen saturation (SpO2) targets. These episodes may increase the risk for retinopathy of prematurity and neurodevelopmental disability. There are no data on the variation in HE and SpO2 targeting between day and night. The aim of this study was to evaluate the difference between day and night on the frequency and severity of HE and achievement of SpO2 targets. Twenty-four mechanically ventilated preterm infants with ≥4 episodes of SpO2 day (9 a.m. to 5 p.m.) were compared to the night (9 p.m. to 5 a.m.) for the frequency of HE and proportion of time within and outside the target SpO2 range (90-95%). The frequency of severe HE (SpO2 night compared to the day (1.6 ± 1.0 vs. 2.4 ± 1.3 episodes/h, p = 0.008, and 0.53 ± 0.35 vs. 0.90 ± 0.54 episodes/h, p = 0.018). There was no difference in mean episode duration. The frequency and duration of mild HE (SpO2 night compared to the day (5.9 ± 2.7 vs. 7.1 ± 2.5 episodes/h, p = 0.003, and 72 ± 15 vs. 87 ± 25 s, p = 0.01, respectively). The proportion of time in severe hypoxemia (SpO2 95%) was greater, during the night compared to the day. The mean FiO2 did not differ between day and night. In this group of infants with frequent HE, nighttime was associated with fewer episodes when compared to daytime. This is likely due to less handling and sensory stimulation during the night. The increase in time spent with hyperoxemia during the night is likely to be due to more tolerance of high SpO2 with less proactive weaning of FiO2. © 2017 S. Karger AG, Basel.

  12. Cerebral and Renal Oxygen Saturation Are Not Compromised in the Presence of Retrograde Blood Flow in either the Ascending or Descending Aorta in Term or Near-Term Infants with Left-Sided Obstructive Lesions.

    Science.gov (United States)

    van der Laan, Michelle E; Mebius, Mirthe J; Roofthooft, Marcus T R; Bos, Arend F; Berger, Rolf M F; Kooi, Elisabeth M W

    2017-01-01

    In infants with left-sided obstructive lesions (LSOL), the presence of retrograde blood flow in either the ascending or descending aorta may lead to diminished cerebral and renal blood flow, respectively. Our aim was to compare cerebral and renal tissue oxygen saturation (rSO2) between infants with LSOL with antegrade and retrograde blood flow in the ascending aorta and with and without diastolic backflow in the descending aorta. Based on 2 echocardiograms, the study group was categorized according to the direction of blood flow in the ascending and descending aorta. We measured cerebral and renal rSO2 using near-infrared spectroscopy and calculated fractional tissue oxygen extraction (FTOE). Nineteen infants with LSOL, admitted to the NICU between 0 and 28 days after birth, were included. Infants with antegrade blood flow (n = 12) and infants with retrograde blood flow in the ascending aorta (n = 7) had similar cerebral rSO2 and FTOE during both echocardiograms. Only during the first echocardiogram, infants with retrograde blood flow in the ascending aorta had lower renal FTOE (0.14 vs. 0.32, p = 0.04) and tended to have higher renal rSO2 (80 vs. 65%, p = 0.09). The presence of diastolic backflow in the descending aorta was not associated with cerebral or renal rSO2 and FTOE during the first (n = 8) as well as the second echocardiogram (n = 10). Retrograde blood flow in the ascending aorta was not associated with cerebral oxygenation, while diastolic backflow in the descending aorta was not associated with renal oxygenation in infants with LSOL. © 2017 S. Karger AG, Basel.

  13. Effect of oxygen at low and high light intensities on the growth of Neochloris oleoabundans

    NARCIS (Netherlands)

    Sousa, C.A.; Compadre, A.; Vermuë, M.H.; Wijffels, R.H.

    2013-01-01

    The effect of partial oxygen pressure on growth of Neochloris oleoabundans was studied at near-saturating light intensity in a fully-controlled photobioreactor. At the partial oxygen pressures tested (PO2=0.24; 0.42; 0.63; 0.84 bar), the specific growth rate was 1.36; 1.16; 0.93 and 0.68 day-1,

  14. Effect of oxygen partial pressure on the density of antiphase boundaries in Fe3O4 thin films on Si(100)

    Science.gov (United States)

    Singh, Suraj Kumar; Husain, Sajid; Kumar, Ankit; Chaudhary, Sujeet

    2018-02-01

    Polycrystalline Fe3O4 thin films were grown on Si(100) substrate by reactive DC sputtering at different oxygen partial pressures PO2 for controlling the growth associated density of antiphase boundaries (APBs). The micro-Raman analyses were performed to study the structural and electronic properties in these films. The growth linked changes in the APBs density are probed by electron-phonon coupling strength (λ) and isothermal magnetization measurements. The estimated values of λ are found to vary from 0.39 to 0.56 with the increase in PO2 from 2.2 × 10-5 to 3.0 × 10-5 Torr, respectively. The saturation magnetization (saturation field) values are found to increase (decrease) from 394 (5.9) to 439 (3.0) emu/cm3 (kOe) with the increase in PO2 . The sharp Verwey transition (∼120 K), low saturation field, high saturation magnetization and low value of λ (comparable to the bulk value ∼0.51) clearly affirm the negligible amount of APBs in the high oxygen partial pressure deposited thin films.

  15. Effects of beach-chair position and induced hypotension on cerebral oxygen saturation in patients undergoing arthroscopic shoulder surgery.

    Science.gov (United States)

    Lee, Jae Hoon; Min, Kyeong Tae; Chun, Yong-Min; Kim, Eun Jung; Choi, Seung Ho

    2011-07-01

    We investigated the effects of the beach-chair position and induced hypotension on regional cerebral oxygen saturation (rSO(2)) in patients undergoing arthroscopic shoulder surgery by using near-infrared spectroscopy. Twenty-eight patients scheduled for arthroscopic shoulder surgery were enrolled prospectively. After induction of anesthesia, mechanical ventilation was controlled to maintain Paco(2) at 35 to 40 mm Hg. Anesthesia was maintained with sevoflurane and remifentanil. After radial artery cannulation, mean arterial pressure (MAP) was measured at the external auditory meatus level and maintained between 60 and 65 mm Hg. The rSO(2) was measured by use of near-infrared spectroscopy. MAP and rSO(2) were recorded at the following times: before induction (T(0)), immediately after induction (T(1) [baseline]), after beach-chair position (T(2)), immediately after induced hypotension (T(3)), 1 hour after induced hypotension (T(4)), and after supine position at the end of surgery (T(5)). Cerebral desaturation was defined as a reduction in rSO(2) to less than 80% of baseline value for 15 seconds or greater. A total of 27 patients were evaluated until the end of this study. The MAP at T(2) was significantly lower than that at T(1). The MAP values at T(3) and T(4) were significantly lower than those at T(1) and T(2). The rSO(2) at T(2) was significantly lower than that at T(1). Unlike the pattern of change in the MAP, there was no additional decrease in rSO(2) at T(3) and T(4). There were 2 patients who had an episode of cerebral desaturation. The beach-chair position combined with induced hypotension significantly decreases rSO(2) in patients undergoing shoulder arthroscopic surgery under general anesthesia. Level IV, study of nonconsecutive patients without consistently applied reference gold standard. Copyright © 2011 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.

  16. Evaluación de parámetros fisiológicos en función de la saturación de oxigeno muscular en mujeres con sobrepeso y obesidad. [Evaluation physiological parameters depending on muscle oxygen saturation in overweight and obesity].

    Directory of Open Access Journals (Sweden)

    Aldo Alfonso Vasquez-Bonilla

    2017-01-01

    Full Text Available El objetivo de este estudio fue evaluar parámetros fisiológicos para comparar y correlacionar en función de la saturación de oxigeno muscular y hemoglobina total medida con espectroscopia de infrarrojo cercano no invasivo. La muestra (n=17 mujeres se dividieron en 2 grupos: sobrepeso/obesidad y normopeso, se valoró la composición corporal, parámetros fisiológicos, saturación de oxigeno muscular e indicie de esfuerzo percibido durante la prueba de esfuerzo incremental máxima en un cicloergometro en base a cuatro zonas metabólicas establecidas: fatmax, umbral aeróbico, umbral anaeróbico y zona de consumo máximo de oxígeno. Los resultados se analizaron utilizando el método estadístico Anova de un factor y la correlación de pearsón. Los resultados encontrados en el grupo normopeso la saturación de oxigeno muscular tiene correlación positiva alta con el vo2max durante la zona fatmax y umbral aeróbico (r=0,72- p=0,04 (r=0,77 – p=0,02, la frecuencia cardíaca de entrenamiento (r= -0,87 – p=0,01 tiene correlación negativa muy alta en la zona umbral anaeróbico, en el grupo sobrepeso obesidad no se encontró ninguna correlación. En conclusión las mujeres con normopeso la saturación de oxigeno muscular medida con espectroscopia de infrarrojo cercano no invasivo puede ser un buen parámetro fisiológico para programar ejercicio en la zonas fatmax, umbral aeróbico y umbral anaeróbico, pero en las mujeres con sobrepeso y obesidad se necesitan más estudios. Abstract The objective of this study was to compare physiological parameters and correlate function of muscle oxygen saturation and total hemoglobin measured with near-infrared spectroscopy noninvasive. The sample (n = 17 women were divided into 2 groups: overweight / obese and normal weight, was measured body composition, physiological parameters, saturation of muscle oxygen and index of perceived exertion during testing maximum incremental exercise on a cycle ergometer

  17. Dependence of nitrite oxidation on nitrite and oxygen in low-oxygen seawater

    Science.gov (United States)

    Sun, Xin; Ji, Qixing; Jayakumar, Amal; Ward, Bess B.

    2017-08-01

    Nitrite oxidation is an essential step in transformations of fixed nitrogen. The physiology of nitrite oxidizing bacteria (NOB) implies that the rates of nitrite oxidation should be controlled by concentration of their substrate, nitrite, and the terminal electron acceptor, oxygen. The sensitivities of nitrite oxidation to oxygen and nitrite concentrations were investigated using 15N tracer incubations in the Eastern Tropical North Pacific. Nitrite stimulated nitrite oxidation under low in situ nitrite conditions, following Michaelis-Menten kinetics, indicating that nitrite was the limiting substrate. The nitrite half-saturation constant (Ks = 0.254 ± 0.161 μM) was 1-3 orders of magnitude lower than in cultivated NOB, indicating higher affinity of marine NOB for nitrite. The highest rates of nitrite oxidation were measured in the oxygen depleted zone (ODZ), and were partially inhibited by additions of oxygen. This oxygen sensitivity suggests that ODZ specialist NOB, adapted to low-oxygen conditions, are responsible for apparently anaerobic nitrite oxidation.

  18. Ventilation onset prior to umbilical cord clamping (physiological-based cord clamping improves systemic and cerebral oxygenation in preterm lambs.

    Directory of Open Access Journals (Sweden)

    Graeme R Polglase

    Full Text Available As measurement of arterial oxygen saturation (SpO2 is common in the delivery room, target SpO2 ranges allow clinicians to titrate oxygen therapy for preterm infants in order to achieve saturation levels similar to those seen in normal term infants in the first minutes of life. However, the influence of the onset of ventilation and the timing of cord clamping on systemic and cerebral oxygenation is not known.We investigated whether the initiation of ventilation, prior to, or after umbilical cord clamping, altered systemic and cerebral oxygenation in preterm lambs.Systemic and cerebral blood-flows, pressures and peripheral SpO2 and regional cerebral tissue oxygenation (SctO2 were measured continuously in apnoeic preterm lambs (126±1 day gestation. Positive pressure ventilation was initiated either 1 prior to umbilical cord clamping, or 2 after umbilical cord clamping. Lambs were monitored intensively prior to intervention, and for 10 minutes following umbilical cord clamping.Clamping the umbilical cord prior to ventilation resulted in a rapid decrease in SpO2 and SctO2, and an increase in arterial pressure, cerebral blood flow and cerebral oxygen extraction. Ventilation restored oxygenation and haemodynamics by 5-6 minutes. No such disturbances in peripheral or cerebral oxygenation and haemodynamics were observed when ventilation was initiated prior to cord clamping.The establishment of ventilation prior to umbilical cord clamping facilitated a smooth transition to systemic and cerebral oxygenation following birth. SpO2 nomograms may need to be re-evaluated to reflect physiological management of preterm infants in the delivery room.

  19. Barley seed radiosensitivity following post-hydration in oxygen-, nitrogen- and nitrous oxide-saturated water, 1; Influence of caffeine and t-butyl alcohol

    Energy Technology Data Exchange (ETDEWEB)

    Singh, S.P.; Kesavan, P.C. (Jawaharlal Nehru Univ., New Delhi (India). School of Life Sciences)

    1990-06-01

    Dry ({approx}3.5 and 4.0 per cent moisture content) barley seeds were exposed to 350 Gy of {sup 60}Co-{gamma}-rays in vacuo and post-hydrated at 4degC for 8 h in O{sub 2}-, N{sub 2}-, or N{sub 2}O-saturated water. The effect of caffeine and t-butyl alcohol (t-BuOH) dissolved in the post-hydration medium on the magnitude of damage developing under these three different gaseous circumstances was studied. The post-irradiation damage and its modification by caffeine and t-BuOH was assessed in terms of 8-day-old seedling injury, peroxidase activity and total peroxides in the 8-day-old seedlings. Post-irradiation O{sub 2}-saturated hydration caused maximal 8-day-old seedling injury, and increased peroxidase activity with concomitant reduction in total peroxides. Both caffeine and t-BuOH afforded significant radioprotection against post-irradiation O{sub 2}-dependent damage. Post-irradiation N{sub 2}O-saturated hydration was even more significantly radioprotective than the N{sub 2}-saturated post-hydration. Under these circumstances, t-BuOH exerted no effect whatsoever on the N{sub 2}- and N{sub 2}O-mediated post-irradiation damage. Caffeine, on the other hand, significantly potentiated these two components of damage. A brief consideration of the physicochemical events which possibly account for the observed effects is presented. (author).

  20. On the Least-Squares Fitting of Slater-Type Orbitals with Gaussians: Reproduction of the STO-NG Fits Using Microsoft Excel and Maple

    Science.gov (United States)

    Pye, Cory C.; Mercer, Colin J.

    2012-01-01

    The symbolic algebra program Maple and the spreadsheet Microsoft Excel were used in an attempt to reproduce the Gaussian fits to a Slater-type orbital, required to construct the popular STO-NG basis sets. The successes and pitfalls encountered in such an approach are chronicled. (Contains 1 table and 3 figures.)

  1. Physiological closed-loop control in intelligent oxygen therapy: A review.

    Science.gov (United States)

    Sanchez-Morillo, Daniel; Olaby, Osama; Fernandez-Granero, Miguel Angel; Leon-Jimenez, Antonio

    2017-07-01

    Oxygen therapy has become a standard care for the treatment of patients with chronic obstructive pulmonary disease and other hypoxemic chronic lung diseases. In current systems, manually continuous adjustment of O 2 flow rate is a time-consuming task, often unsuccessful, that requires experienced staff. The primary aim of this systematic review is to collate and report on the principles, algorithms and accuracy of autonomous physiological close-loop controlled oxygen devices as well to present recommendations for future research and studies in this area. A literature search was performed on medical database MEDLINE, engineering database IEEE-Xplore and wide-raging scientific databases Scopus and Web of Science. A narrative synthesis of the results was carried out. A summary of the findings of this review suggests that when compared to the conventional manual practice, the closed-loop controllers maintain higher saturation levels, spend less time below the target saturation, and save oxygen resources. Nonetheless, despite of their potential, autonomous oxygen therapy devices are scarce in real clinical applications. Robustness of control algorithms, fail-safe mechanisms, limited reliability of sensors, usability issues and the need for standardized evaluating methods of assessing risks can be among the reasons for this lack of matureness and need to be addressed before the wide spreading of a new generation of automatic oxygen devices. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. Temperature dependence of sulfide and sulfate solubility in olivine-saturated basaltic magmas

    Science.gov (United States)

    Beermann, O.; Botcharnikov, R. E.; Holtz, F.; Diedrich, O.; Nowak, M.

    2011-12-01

    The sulfur concentration at pyrrhotite- and anhydrite-saturation in primitive hydrous basaltic melt of the 2001-2002 eruption of Mt. Etna was determined at 200 MPa, T = 1050-1250 °C and at log fO 2 from FMQ to FMQ+2.2 (FMQ is Fayalite-Magnetite-Quartz oxygen buffer). At 1050 °C Au sample containers were used. A double-capsule technique, using a single crystal olivine sample container closed with an olivine piston, embedded in a sealed Au 80Pd 20 capsule, was developed to perform experiments in S-bearing hydrous basaltic systems at T > 1050 °C. Pyrrhotite is found to be a stable phase coexisting with melt at FMQ-FMQ+0.3, whereas anhydrite is stable at FMQ+1.4-FMQ+2.2. The S concentration in the melt increases almost linearly from 0.12 ± 0.01 to 0.39 ± 0.02 wt.% S at FeS-saturation and from 0.74 ± 0.01 to 1.08 ± 0.04 wt.% S at anhydrite-saturation with T ranging from 1050-1250 °C. The relationships between S concentration at pyrrhotite and/or anhydrite saturation, MgO content of the olivine-saturated melt, T, and log fO 2 observed in this study and from previous data are used to develop an empirical model for estimating the magmatic T and fO 2 from the S and MgO concentrations of H 2O-bearing olivine-saturated basaltic melts. The model can also be used to determine maximum S concentrations, if fO 2 and MgO content of the melt are known. The application of the model to compositions of melt inclusions in olivines from Mt. Etna indicates that the most primitive magmas trapped in inclusions might have been stored at log fO 2 slightly higher than FMQ+1 and at T = 1100-1150 °C, whereas more evolved melts could have been trapped at T ⩽ 1100 °C. These values are in a good agreement with the estimates obtained by other independent methods reported in the literature.

  3. Stochastic semi-nonparametric frontier estimation of electricity distribution networks: Application of the StoNED method in the Finnish regulatory model

    International Nuclear Information System (INIS)

    Kuosmanen, Timo

    2012-01-01

    Electricity distribution network is a prime example of a natural local monopoly. In many countries, electricity distribution is regulated by the government. Many regulators apply frontier estimation techniques such as data envelopment analysis (DEA) or stochastic frontier analysis (SFA) as an integral part of their regulatory framework. While more advanced methods that combine nonparametric frontier with stochastic error term are known in the literature, in practice, regulators continue to apply simplistic methods. This paper reports the main results of the project commissioned by the Finnish regulator for further development of the cost frontier estimation in their regulatory framework. The key objectives of the project were to integrate a stochastic SFA-style noise term to the nonparametric, axiomatic DEA-style cost frontier, and to take the heterogeneity of firms and their operating environments better into account. To achieve these objectives, a new method called stochastic nonparametric envelopment of data (StoNED) was examined. Based on the insights and experiences gained in the empirical analysis using the real data of the regulated networks, the Finnish regulator adopted the StoNED method in use from 2012 onwards.

  4. Alveolar gas exchange and tissue oxygenation during incremental treadmill exercise, and their associations with blood O2 carrying capacity

    Directory of Open Access Journals (Sweden)

    Antti-Pekka E. Rissanen

    2012-07-01

    Full Text Available The magnitude and timing of oxygenation responses in highly active leg muscle, less active arm muscle, and cerebral tissue, have not been studied with simultaneous alveolar gas exchange measurement during incremental treadmill exercise. Nor is it known, if blood O2 carrying capacity affects the tissue-specific oxygenation responses. Thus, we investigated alveolar gas exchange and tissue (m. vastus lateralis, m. biceps brachii, cerebral cortex oxygenation during incremental treadmill exercise until volitional fatigue, and their associations with blood O2 carrying capacity in 22 healthy men. Alveolar gas exchange was measured, and near-infrared spectroscopy (NIRS was used to monitor relative concentration changes in oxy- (Δ[O2Hb], deoxy- (Δ[HHb] and total hemoglobin (Δ[tHb], and tissue saturation index (TSI. NIRS inflection points (NIP, reflecting changes in tissue-specific oxygenation, were determined and their coincidence with ventilatory thresholds (anaerobic threshold (AT, respiratory compensation point (RC; V-slope method was examined. Blood O2 carrying capacity (total hemoglobin mass (tHb-mass was determined with the CO-rebreathing method. In all tissues, NIPs coincided with AT, whereas RC was followed by NIPs. High tHb-mass associated with leg muscle deoxygenation at peak exercise (e.g., Δ[HHb] from baseline walking to peak exercise vs. tHb-mass: r = 0.64, p < 0.01, but not with arm muscle- or cerebral deoxygenation. In conclusion, regional tissue oxygenation was characterized by inflection points, and tissue oxygenation in relation to alveolar gas exchange during incremental treadmill exercise resembled previous findings made during incremental cycling. It was also found out, that O2 delivery to less active m. biceps brachii may be limited by an accelerated increase in ventilation at high running intensities. In addition, high capacity for blood O2 carrying was associated with a high level of m. vastus lateralis deoxygenation at peak

  5. Oxygen status during haemodialysis. The Cord-Group

    DEFF Research Database (Denmark)

    Nielsen, A L; Jensen, H Æ; Hegbrant, J

    1995-01-01

    Hypoxia during haemodialysis, mainly acetate, has been reported several times. In our study we have monitored oxygen status during 258 bicarbonate haemodialyses. A significant drop below 80 mmHg in mean oxygen tension occurred. Mean oxygen saturation reflected this drop but did not reach levels...... below 90%. The mean oxygen concentration was on the whole critical low, though slightly increasing during each haemodialysis session due to ultrafiltration. It is concluded that both hypoxia and hypoxaemia do occur during bicarbonate haemodialysis. To a group of patients generally having limited cardiac...... reserves, a poor oxygen status is a potentially serious complication to haemodialysis. Monitoring oxygen status is thus advisable....

  6. Oxygen titration after resuscitation from out-of-hospital cardiac arrest: a multi-centre, randomised controlled pilot study (the EXACT pilot trial).

    Science.gov (United States)

    Bray, Janet E; Hein, Cindy; Smith, Karen; Stephenson, Michael; Grantham, Hugh; Finn, Judith; Stub, Dion; Cameron, Peter

    2018-04-20

    Recent studies suggest the administration of 100% oxygen to hyperoxic levels following return-of-spontaneous-circulation (ROSC) post-cardiac arrest may be harmful. However, the feasibility and safety of oxygen titration in the prehospital setting is unknown. We conducted a multi-centre, phase-2 study testing whether prehospital titration of oxygen results in an equivalent number of patients arriving at hospital with oxygen saturations SpO2 ≥ 94%. We enrolled unconscious adults with: sustained ROSC; initial shockable rhythm; an advanced airway; and an SpO2 ≥ 95%. Initially (Sept 2015-March 2016) patients were randomised 1:1 to either 2 litres/minute (L/min) oxygen (titrated) or >10 L/min oxygen (control) via a bag-valve reservoir. However, one site experienced a high number of desaturations (SpO2 titrated arm and this arm was changed (April 2016) to an initial reduction of oxygen to 4 L/min then, if tolerated, to 2 L/min, and the desaturation limit was decreased to titrated (n = 37: 2L/min = 20 and 2-4 L/min = 17) oxygen or control (n = 24). Patients allocated to titrated oxygen were more likely to desaturate compared to controls ((SpO2 titrated: 90% vs. control: 100%) and all patients had a SpO2 ≥ 90%. One patient (control) re-arrested. Survival to hospital discharge was similar. Oxygen titration post-ROSC is feasible in the prehospital environment, but incremental titration commencing at 4L/min oxygen flow may be needed to maintain an oxygen saturation >90% (NCT02499042). Copyright © 2018. Published by Elsevier B.V.

  7. Comparison of the OxyMask and Venturi mask in the delivery of supplemental oxygen: Pilot study in oxygen-dependent patients

    Science.gov (United States)

    Beecroft, Jaime M; Hanly, Patrick J

    2006-01-01

    BACKGROUND: The OxyMask (Southmedic Inc, Canada) is a new face mask for oxygen delivery that uses a small ‘diffuser’ to concentrate and direct oxygen toward the mouth and nose. The authors hypothesized that this unique design would enable the OxyMask to deliver oxygen more efficiently than a Venturi mask (Hudson RCI, USA) in patients with chronic hypoxemia. METHODS: Oxygen-dependent patients with chronic, stable respiratory disease were recruited to compare the OxyMask and Venturi mask in a randomized, single-blind, cross-over design. Baseline blood oxygen saturation (SaO2) was established breathing room air, followed in a random order by supplemental oxygen through the OxyMask or Venturi mask. Oxygen delivery was titrated to maintain SaO2 4% to 5% and 8% to 9% above baseline for two separate 30 min periods of stable breathing. Oxygen flow rate, partial pressure of inspired and expired oxygen (PO2) and carbon dioxide (PCO2), minute ventilation, heart rate, nasal and oral breathing, SaO2 and transcutaneous PCO2 were collected continuously. The study was repeated following alterations to the OxyMask design, which improved clearance of carbon dioxide. RESULTS: Thirteen patients, aged 28 to 79 years, were studied initially using the original OxyMask. Oxygen flow rate was lower, inspired PO2 was higher and expired PO2 was lower while using the OxyMask. Minute ventilation and inspired and expired PCO2 were significantly higher while using the OxyMask, whereas transcutaneous PCO2, heart rate and the ratio of nasal to oral breathing did not change significantly throughout the study. Following modification of the OxyMask, 13 additional patients, aged 18 to 79 years, were studied using the same protocol. The modified OxyMask provided a higher inspired PO2 at a lower flow rate, without evidence of carbon dioxide retention. CONCLUSIONS: Oxygen is delivered safely and more efficiently by the OxyMask than by the Venturi mask in stable oxygen-dependent patients. PMID:16896425

  8. Effects of whole body UV-irradiation on oxygen delivery from the erythrocyte

    International Nuclear Information System (INIS)

    Humpeler, E.; Mairbaeurl, H.; Hoenigsmann, H.

    1982-01-01

    In 16 healthy caucasian volunteers (mean age: 22.2 years) the influence of whole body UV-irradiation on the oxygen transport properties of erythrocytes was investigated. Four hours after irradiation with UV (using the minimal erythema dose, MED) no variation of haemoglobin concentration, hematocrit, mean corpuscular haemoglobin concentration, pH or standard bicarbonate could be found, whereas inorganic plasma phosphate (Psub(i)), calcium, the intraerythrocytic 2,3-diphosphoglycerate (2,3-DPG), the activity of erythrocytic phosphofructokinase (PFK) and pyruvatekinase (PK) increased significantly. The half saturation tension of oxygen (P 50 -value) tended to increase. The increase of Psub(i) causes - via a stimulation of the glycolytic pathway - an increase in 2,3-DPG concentration and thus results in a shift of the oxygen dissociation curve. It is therefore possible to enhance tissue oxygenation by whole body UV-irradiation. (orig.)

  9. Khater method for nonlinear Sharma Tasso-Olever (STO) equation of fractional order

    Science.gov (United States)

    Bibi, Sadaf; Mohyud-Din, Syed Tauseef; Khan, Umar; Ahmed, Naveed

    In this work, we have implemented a direct method, known as Khater method to establish exact solutions of nonlinear partial differential equations of fractional order. Number of solutions provided by this method is greater than other traditional methods. Exact solutions of nonlinear fractional order Sharma Tasso-Olever (STO) equation are expressed in terms of kink, travelling wave, periodic and solitary wave solutions. Modified Riemann-Liouville derivative and Fractional complex transform have been used for compatibility with fractional order sense. Solutions have been graphically simulated for understanding the physical aspects and importance of the method. A comparative discussion between our established results and the results obtained by existing ones is also presented. Our results clearly reveal that the proposed method is an effective, powerful and straightforward technique to work out new solutions of various types of differential equations of non-integer order in the fields of applied sciences and engineering.

  10. MR Imaging-derived Oxygen-Hemoglobin Dissociation Curves and Fetal-Placental Oxygen-Hemoglobin Affinities.

    Science.gov (United States)

    Avni, Reut; Golani, Ofra; Akselrod-Ballin, Ayelet; Cohen, Yonni; Biton, Inbal; Garbow, Joel R; Neeman, Michal

    2016-07-01

    Purpose To generate magnetic resonance (MR) imaging-derived, oxygen-hemoglobin dissociation curves and to map fetal-placental oxygen-hemoglobin affinity in pregnant mice noninvasively by combining blood oxygen level-dependent (BOLD) T2* and oxygen-weighted T1 contrast mechanisms under different respiration challenges. Materials and Methods All procedures were approved by the Weizmann Institutional Animal Care and Use Committee. Pregnant mice were analyzed with MR imaging at 9.4 T on embryonic days 14.5 (eight dams and 58 fetuses; imprinting control region ICR strain) and 17.5 (21 dams and 158 fetuses) under respiration challenges ranging from hyperoxia to hypoxia (10 levels of oxygenation, 100%-10%; total imaging time, 100 minutes). A shorter protocol with normoxia to hyperoxia was also performed (five levels of oxygenation, 20%-100%; total imaging time, 60 minutes). Fast spin-echo anatomic images were obtained, followed by sequential acquisition of three-dimensional gradient-echo T2*- and T1-weighted images. Automated registration was applied to align regions of interest of the entire placenta, fetal liver, and maternal liver. Results were compared by using a two-tailed unpaired Student t test. R1 and R2* values were derived for each tissue. MR imaging-based oxygen-hemoglobin dissociation curves were constructed by nonlinear least square fitting of 1 minus the change in R2*divided by R2*at baseline as a function of R1 to a sigmoid-shaped curve. The apparent P50 (oxygen tension at which hemoglobin is 50% saturated) value was derived from the curves, calculated as the R1 scaled value (x) at which the change in R2* divided by R2*at baseline scaled (y) equals 0.5. Results The apparent P50 values were significantly lower in fetal liver than in maternal liver for both gestation stages (day 14.5: 21% ± 5 [P = .04] and day 17.5: 41% ± 7 [P hemoglobin dissociation curves with a shorter protocol that excluded the hypoxic periods was demonstrated. Conclusion MR imaging

  11. Correlation between near-infrared spectroscopy and magnetic resonance imaging of rat brain oxygenation modulation

    International Nuclear Information System (INIS)

    Chen Yu; Tailor, Dharmesh R; Intes, Xavier; Chance, Britton

    2003-01-01

    We measure the tissue oxygen and haemoglobin concentrations in the rat brain during modulation of inhaled oxygen concentration (FiO 2 ), using non-invasive frequency domain near-infrared oximetry. The rise in oxygenated haemoglobin concentration and the decline in deoxygenated haemoglobin concentration are demonstrated in correspondence with the modulation of FiO 2 , which is changed from 20% to 100% in increments of 20%. Furthermore, the tissue oxygenation saturation also shows the corresponding trend and changes ranging from approximately 70% to 90%. The relative changes in deoxygenated haemoglobin concentration are compared to the blood-oxygenation-level-dependent (BOLD) MRI signal recorded during a similar FiO 2 protocol. A linear relationship with high correlation coefficient between the relative changes in the BOLD MRI signal and the NIRS signal is observed

  12. Correlation between near-infrared spectroscopy and magnetic resonance imaging of rat brain oxygenation modulation

    Energy Technology Data Exchange (ETDEWEB)

    Chen Yu [Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, PA (United States); Tailor, Dharmesh R [Department of Bioengineering, University of Pennsylvania, Philadelphia, PA (United States); Intes, Xavier [Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, PA (United States); Chance, Britton [Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, PA (United States)

    2003-02-21

    We measure the tissue oxygen and haemoglobin concentrations in the rat brain during modulation of inhaled oxygen concentration (FiO{sub 2}), using non-invasive frequency domain near-infrared oximetry. The rise in oxygenated haemoglobin concentration and the decline in deoxygenated haemoglobin concentration are demonstrated in correspondence with the modulation of FiO{sub 2}, which is changed from 20% to 100% in increments of 20%. Furthermore, the tissue oxygenation saturation also shows the corresponding trend and changes ranging from approximately 70% to 90%. The relative changes in deoxygenated haemoglobin concentration are compared to the blood-oxygenation-level-dependent (BOLD) MRI signal recorded during a similar FiO{sub 2} protocol. A linear relationship with high correlation coefficient between the relative changes in the BOLD MRI signal and the NIRS signal is observed.

  13. Gluon saturation in a saturated environment

    International Nuclear Information System (INIS)

    Kopeliovich, B. Z.; Potashnikova, I. K.; Schmidt, Ivan

    2011-01-01

    A bootstrap equation for self-quenched gluon shadowing leads to a reduced magnitude of broadening for partons propagating through a nucleus. Saturation of small-x gluons in a nucleus, which has the form of transverse momentum broadening of projectile gluons in pA collisions in the nuclear rest frame, leads to a modification of the parton distribution functions in the beam compared with pp collisions. In nucleus-nucleus collisions all participating nucleons acquire enhanced gluon density at small x, which boosts further the saturation scale. Solution of the reciprocity equations for central collisions of two heavy nuclei demonstrate a significant, up to several times, enhancement of Q sA 2 , in AA compared with pA collisions.

  14. Characterization of hemodynamics and oxygenation in the renal cortex of rats

    Science.gov (United States)

    Grosenick, Dirk; Wabnitz, Heidrun; Macdonald, Rainer; Niendorf, Thoralf; Cantow, Kathleen; Flemming, Bert; Arakelyan, Karen; Seeliger, Erdmann

    2015-03-01

    We have performed a pre-clinical study on 13 rats to investigate the potential of near-infrared spectroscopy for quantification of hemoglobin concentration and oxygen saturation of hemoglobin in the renal cortex of small animals. These measurements were combined with laser-Doppler fluxmetry and a fluorescence quenching technique for quantification of tissue oxygen tension. Hemoglobin concentration and oxygen saturation were determined from experimental data by a Monte Carlo model. The methods were applied to investigate and compare temporal changes during several types of interventions such as arterial and venous occlusions, as well as hyperoxia, hypoxia and hypercapnia induced by different mixtures of the inspired gas.

  15. Interplay of crystal fractionation, sulfide saturation and oxygen fugacity on the iron isotope composition of arc lavas: An example from the Marianas

    Science.gov (United States)

    Williams, H. M.; Prytulak, J.; Woodhead, J. D.; Kelley, K. A.; Brounce, M.; Plank, T.

    2018-04-01

    Subduction zone systems are central to a multitude of processes from the evolution of the continental crust to the concentration of metals into economically viable deposits. The interplay between oxygen fugacity, sulfur saturation, fluid exsolution and fractionating mineral assemblages that gives rise to typical arc magma chemical signatures is, however, still poorly understood and novel geochemical approaches are required to make further progress. Here we examine a well-characterized suite of arc lavas from the Marianas (W. Pacific) for their stable Fe isotope composition. In agreement with previous work and mass balance considerations, contributions from sediments and/or fluids are shown to have negligible effect on Fe isotopes. Instead, we focus on disentangling processes occurring during basalt through dacite differentiation using a sample suite from the island of Anatahan. Anatahan whole rock Fe isotope compositions (δ57Fe) range from -0.05 ± 0.05 to 0.17 ± 0.03 (2 S.D.)‰. A fractionation model is constructed, where three distinct stages of differentiation are required to satisfy the combined major and trace element and isotopic observations. In particular, the sequestration of isotopically heavy Fe into magnetite and isotopically light Fe into sulfide melts yields important constraints. The data require that lavas are first undersaturated with respect to crystalline or molten sulfide, followed by the crystallisation of magnetite, which then triggers late sulfide saturation. The model demonstrates that the final stage of removal of liquid or crystalline sulfide can effectively sequester Cu (and presumably other chalcophiles) and that late stage exsolution of magmatic fluids or brines may not be required to do this, although these processes are not mutually exclusive. Finally, the new Fe isotope data are combined with previous Tl-Mo-V stable isotope determinations on the same samples. Importantly, the multi-valent transition metal stable isotope systems of

  16. 3-D Numerical Investigation on Oxygen Transfer in a Horizontal Venturi Flow with Two Holes

    Directory of Open Access Journals (Sweden)

    Zegao Yin

    2018-02-01

    Full Text Available In order to investigate the dissolved oxygen increase caused by air suction in a horizontal Venturi flow with two holes, a 3-D computational fluid dynamics model was used to explore the water and bubble mixture flow, coupled with a dissolved oxygen transfer model. A series of experiments were conducted to validate the mathematical model. A relative saturation coefficient correlation was examined factoring in dissolved oxygen concentration at the inlet, water velocity at the inlet, the hole’s diameter, contraction ratio at throat section, and the downstream length of Venturi pipe. It was found that the relative saturation coefficient increases with increasing dissolved oxygen concentration at the inlet and downstream length of Venturi pipe respectively. However, it increases with decreasing water velocity at the inlet and contraction ratio at the throat section to some extent. The hole’s diameter plays a complex role in the relative saturation coefficient. The dimensional analysis method and the least square method were used to deduce a simple formula for the relative saturation coefficient, and this was consistent with related data.

  17. Effect of oxygen fugacity on OH dissolution in olivine under peridotite-saturated conditions: An experimental study at 1.5-7 GPa and 1100-1300 °C

    Science.gov (United States)

    Yang, Xiaozhi

    2016-01-01

    The dissolution of OH in olivine by experimental studies at simulated conditions has attracted increasing interest over the past three decades, and the influence of pressure, temperature and composition has been relatively well constrained. Oxygen fugacity is highly heterogeneous in the upper mantle, on both temporal and spatial scales, and is an important parameter in characterizing many chemical and physical processes in the mantle. However, less attention has been devoted to the effect of oxygen fugacity on OH dissolution in olivine, and the only few available reports on this topic have led to significant inconsistency and debate. In this study, the correlation between oxygen fugacity and OH solubility in Fe-bearing olivine has been systematically investigated by conducting experiments at 1.5-7 GPa and 1100-1300 °C and under peridotite- and fluid-saturated conditions, with natural gem-quality olivine single crystals and fresh peridotite xenoliths as starting materials and with oxygen fugacity controlled by the Fe-FeO, Ni-NiO and Fe2O3-Fe3O4 oxygen buffer pairs. The water concentrations were determined by polarized analyses using a Fourier-transform infrared spectroscopy. The results show that, at all the experimental conditions, the OH bands at both high frequency (∼3650-3450 cm-1) and low frequency (∼3450-3100 cm-1) are prominent. The intensity of OH bands at ∼3355 and 3325 cm-1 increases positively with oxygen fugacity, suggesting a dominant role of Fe3+ in their incorporation. Under otherwise identical conditions, the water content is gradually enhanced with increasing pressure, temperature or oxygen fugacity. The effect of oxygen fugacity on the enhancement of OH solubility appears not sensitive to temperature (1100-1300 °C) at a given pressure, but becomes progressively stronger with increasing pressure from 1.5 to 7 GPa given the temperature. Relative to oxygen fugacity buffers, the OH solubility is on average increased by ∼50% between Fe-FeO and

  18. Charge modulated interfacial conductivity in SrTiO3-based oxide heterostructures

    DEFF Research Database (Denmark)

    Chen, Yunzhong; Stamate, Eugen; Pryds, Nini

    2011-01-01

    When depositing amorphous SrTiO3 (STO) films on crystalline STO substrates by pulsed laser deposition, metallic interfaces are observed, though both materials are band-gap insulators. The interfacial conductivity exhibits strong dependence on oxygen pressure during film growth, which is closely...

  19. Optimizing oxygenation and intubation conditions during awake fibre-optic intubation using a high-flow nasal oxygen-delivery system.

    Science.gov (United States)

    Badiger, S; John, M; Fearnley, R A; Ahmad, I

    2015-10-01

    Awake fibre-optic intubation is a widely practised technique for anticipated difficult airway management. Despite the administration of supplemental oxygen during the procedure, patients are still at risk of hypoxia because of the effects of sedation, local anaesthesia, procedural complications, and the presence of co-morbidities. Traditionally used oxygen-delivery devices are low flow, and most do not have a sufficient reservoir or allow adequate fresh gas flow to meet the patient's peak inspiratory flow rate, nor provide an adequate fractional inspired oxygen concentration to prevent desaturation should complications arise. A prospective observational study was conducted using a high-flow humidified transnasal oxygen-delivery system during awake fibre-optic intubation in 50 patients with anticipated difficult airways. There were no episodes of desaturation or hypercapnia using the high-flow system, and in all patients the oxygen saturation improved above baseline values, despite one instance of apnoea resulting from over-sedation. All patients reported a comfortable experience using the device. The high-flow nasal oxygen-delivery system improves oxygenation saturation, decreases the risk of desaturation during the procedure, and potentially, optimizes conditions for awake fibre-optic intubation. The soft nasal cannulae uniquely allow continuous oxygenation and simultaneous passage of the fibrescope and tracheal tube. The safety of the procedure may be increased, because any obstruction, hypoventilation, or periods of apnoea that may arise may be tolerated for longer, allowing more time to achieve ventilation in an optimally oxygenated patient. © The Author 2015. Published by Oxford University Press on behalf of the British Journal of Anaesthesia. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  20. Oxygen concentrators performance with nitrous oxide at 50:50 volume

    Directory of Open Access Journals (Sweden)

    Jorge Ronaldo Moll

    2014-06-01

    Full Text Available Background and objectives: Few investigations have addressed the safety of oxygen from concentrators for use in anesthesia in association with nitrous oxide. This study evaluated the percent of oxygen from a concentrator in association with nitrous oxide in a semi-closed rebreathing circuit. Methods: Adult patients undergoing low risk surgery were randomly allocated into two groups, receiving a fresh gas flow of oxygen from concentrators (O293 or of oxygen from concentrators and nitrous oxide (O293N2O. The fraction of inspired oxygen and the percentage of oxygen from fresh gas flow were measured every 10 min. The ratio of FiO2/oxygen concentration delivered was compared at various time intervals and between the groups. Results: Thirty patients were studied in each group. There was no difference in oxygen from concentrators over time for both groups, but there was a significant improvement in the FiO2 (p < 0.001 for O293 group while a significant decline (p < 0.001 for O293N2O. The FiO2/oxygen ratio varied in both groups, reaching a plateau in the O293 group. Pulse oximetry did not fall below 98.5% in either group. Conclusion: The FiO2 in the mixture of O293 and nitrous oxide fell during the observation period although oxygen saturation was higher than 98.5% throughout the study. Concentrators can be considered a stable source of oxygen for use during short anesthetic procedures, either pure or in association with nitrous oxide at 50:50 volume.

  1. Frontal lobe oxygenation is maintained during hypotension following propofol-fentanyl anesthesia

    DEFF Research Database (Denmark)

    Nissen, P.; Lieshout, J.J. van; Nielsen, H.B.

    2009-01-01

    Near-infrared spectroscopy (NIRS) assesses cerebral oxygen saturation (Sco2) as a balance between cerebral oxygen delivery and consumption. In 71 patients, we evaluated whether marked reduction in mean arterial pressure (MAP) during propofol-fentanyl anesthesia induction affects frontal lobe Sco2....... The NIRS-determined arm muscle oxygenation (Smo2), heart rate (HR), and cardiac output (CO) were monitored, endtidal carbon dioxide tension was controlled at 3.5 to 4.5 kPa, and central blood volume was maintained. Before anesthesia, the median (range) MAP, HR, and CO were 93 mm Hg (61-126 mm Hg), 76 beats......, the median (range) NIRS-determined Smo2 also decreased (73% [54%-94%] to 71% [52%-87%]), whereas Sco2 increased from 67% (46%-93%) to 74% (48%-95%) (P anesthesia induction, variables recovered and remained at preanesthetic levels during surgery. The findings...

  2. Oxygen effect in the radiolysis of triton X-100 aqueous solution

    International Nuclear Information System (INIS)

    Perkowski, J.; Mayer, J.

    1994-01-01

    Experiments with Triton X-100 as a model surfactant were performed under steady-state conditions, using deoxygenated solutions as well as those saturated with N 2 O, O 2 or N 2 O/O 2 mixtures. The Triton x-100 decomposition yield was dependent on the O 2 content of the irradiated system. Oxygen promoted surfactant decomposition in aqueous solution containing only Triton X-100. (author) 13 refs.; 1 tab

  3. Under general anesthesia arginine vasopressin prevents hypotension but impairs cerebral oxygenation during arthroscopic shoulder surgery in the beach chair position.

    Science.gov (United States)

    Cho, Soo Y; Kim, Seok J; Jeong, Cheol W; Jeong, Chang Y; Chung, Sung S; Lee, JongUn; Yoo, Kyung Y

    2013-12-01

    Patients undergoing surgery in the beach chair position (BCP) are at a risk of cerebral ischemia. We evaluated the effect of arginine vasopressin (AVP) on hemodynamics and cerebral oxygenation during surgery in the BCP. Thirty patients undergoing shoulder surgery in BCP under propofol-remifentanil anesthesia were randomly allocated either to receive IV AVP 0.07 U/kg (AVP group, N = 15) or an equal volume of saline (control group, N = 15) 2 minutes before taking BCP. Mean arterial blood pressure (MAP), heart rate (HR), jugular venous bulb oxygen saturation (SjvO2), and regional cerebral tissue oxygen saturation (SctO2) were measured after induction of anesthesia and before (presitting in supine position) and after patients took BCP. AVP itself given before the positioning increased MAP and decreased SjvO2 and SctO2 (P 20% SctO2 decrease from presitting value) (80% vs 13%; P = 0.0003) was higher in the AVP group. The incidence of jugular desaturation (SjvO2 shoulder surgery under general anesthesia. However, it was associated with regional cerebral but not jugular venous oxygen desaturation on upright positioning.

  4. Oxygen sensitive polymeric nanocapsules for optical dissolved oxygen sensors

    Science.gov (United States)

    Sun, Zhijuan; Cai, Chenxin; Guo, Fei; Ye, Changhuai; Luo, Yingwu; Ye, Shuming; Luo, Jianchao; Zhu, Fan; Jiang, Chunyue

    2018-04-01

    Immobilization of the oxygen-sensitive probes (OSPs) in the host matrix greatly impacts the performance and long-term usage of the optical dissolved oxygen (DO) sensors. In this work, fluorescent dyes, as the OSPs, were encapsulated with a crosslinked fluorinated polymer shell by interfacial confined reversible addition fragmentation chain transfer miniemulsion polymerization to fabricate oxygen sensitive polymeric nanocapsules (NCs). The location of fluorescent dyes and the fluorescent properties of the NCs were fully characterized by fourier transform infrared spectrometer, x-ray photoelectron spectrometer and fluorescent spectrum. Dye-encapsulated capacity can be precisely tuned from 0 to 1.3 wt% without self-quenching of the fluorescent dye. The crosslinked fluorinated polymer shell is not only extremely high gas permeability, but also prevents the fluorescent dyes from leakage in aqueous as well as in various organic solvents, such as ethanol, acetone and tetrahydrofuran (THF). An optical DO sensor based on the oxygen sensitive NCs was fabricated, showing high sensitivity, short response time, full reversibility, and long-term operational stability of online monitoring DO. The sensitivity of the optical DO sensor is 7.02 (the ratio of the response value in fully deoxygenated and saturated oxygenated water) in the range 0.96-14.16 mg l-1 and the response time is about 14.3 s. The sensor’s work curve was fit well using the modified Stern-Volmer equation by two-site model, and its response values are hardly affected by pH ranging from 2 to 12 and keep constant during continuous measurement for 3 months. It is believed that the oxygen sensitive polymeric NCs-based optical DO sensor could be particularly useful in long-term online DO monitoring in both aqueous and organic solvent systems.

  5. Spontaneous calcium waves in Bergman glia increase with age and hypoxia and may reduce tissue oxygen

    OpenAIRE

    Mathiesen, Claus; Brazhe, Alexey; Thomsen, Kirsten; Lauritzen, Martin

    2012-01-01

    Glial calcium (Ca2+) waves constitute a means to spread signals between glial cells and to neighboring neurons and blood vessels. These waves occur spontaneously in Bergmann glia (BG) of the mouse cerebellar cortex in vivo. Here, we tested three hypotheses: (1) aging and reduced blood oxygen saturation alters wave activity; (2) glial Ca2+ waves change cerebral oxygen metabolism; and (3) neuronal and glial wave activity is correlated. We used two-photon microscopy in the cerebellar cortexes of...

  6. Sulfur concentration at sulfide saturation (SCSS) in magmatic silicate melts

    Science.gov (United States)

    Liu, Yanan; Samaha, Naji-Tom; Baker, Don R.

    2007-04-01

    The sulfur concentration in silicate melts at sulfide saturation (SCSS) was experimentally investigated in a temperature range from 1150 to 1450 °C and a pressure range from 500 MPa to 1 GPa in a piston-cylinder apparatus. The investigated melt compositions varied from rhyolitic to basaltic and water concentrations varied from 0 to ˜9 wt%. All experiments were saturated with FeS melt or pyrrhotite crystals. Temperature was confirmed to have a positive effect on the SCSS. Experimental oxygen fugacities were either near the carbon-carbon monoxide buffer or one log unit above the nickel-nickel oxide buffer, and found to positively affect the SCSS. Combining our results with data from the literature we constructed a model to predict the SCSS in melts ranging in composition from komatiitic to rhyolitic, with water concentrations from 0 to 9 wt%, at pressures from 1 bar to 9 GPa and oxygen fugacities between ˜2 log units below the fayalite-magnetite-quartz buffer to ˜2 log units above it. The coefficients were obtained by multiple linear regression of experimental data and the best model found for the prediction of the SCSS is: ln(Sinppm)=11.35251-{4454.6}/{T}-0.03190{P}/{T}+0.71006ln(MFM)-1.98063[(MFM)(XO)]+0.21867ln(XO)+0.36192lnX where P is in bar, T is in K, MFM is a compositional parameter describing the melt based upon cation mole fractions: MFM={Na+K+2(Ca+Mg+Fe)}/{Si×(Al+Fe)}, XO is the mole fraction of water in the melt, and X is the mole fraction of FeO in the melt. This model was independently tested against experiments performed on anhydrous and hydrous melts in the temperature range from 800 to 1800 °C and 1-9 GPa. The model typically predicts the measured values of the natural log of the SCSS (in ppm) for komatiitic to rhyolitic (˜42 to ˜74 wt% SiO 2) melts to within 5% relative, but is less accurate for high-silica (>76 wt% SiO 2) rhyolites, especially those with molar ratios of iron to sulfur below 2. We demonstrate how this model can be used with

  7. A general model to calculate the spin-lattice (T1) relaxation time of blood, accounting for haematocrit, oxygen saturation and magnetic field strength.

    Science.gov (United States)

    Hales, Patrick W; Kirkham, Fenella J; Clark, Christopher A

    2016-02-01

    Many MRI techniques require prior knowledge of the T1-relaxation time of blood (T1bl). An assumed/fixed value is often used; however, T1bl is sensitive to magnetic field (B0), haematocrit (Hct), and oxygen saturation (Y). We aimed to combine data from previous in vitro measurements into a mathematical model, to estimate T1bl as a function of B0, Hct, and Y. The model was shown to predict T1bl from in vivo studies with a good accuracy (± 87 ms). This model allows for improved estimation of T1bl between 1.5-7.0 T while accounting for variations in Hct and Y, leading to improved accuracy of MRI-derived perfusion measurements. © The Author(s) 2015.

  8. Pulse Oximetry for the Detection of Obstructive Sleep Apnea Syndrome: Can the Memory Capacity of Oxygen Saturation Influence Their Diagnostic Accuracy?

    Directory of Open Access Journals (Sweden)

    Carlos A. Nigro

    2011-01-01

    Full Text Available Objective. To assess the diagnostic ability of WristOx 3100 using its three different recording settings in patients with suspected obstructive sleep apnea syndrome (OSAS. Methods. All participants (135 performed the oximetry (three oximeters WristOx 3100 and polysomnography (PSG simultaneously in the sleep laboratory. Both recordings were interpreted blindly. Each oximeter was set to one of three different recording settings (memory capabilities 0.25, 0.5, and 1 Hz. The software (nVision 5.1 calculated the adjusted O2 desaturation index-mean number of O2 desaturation per hour of analyzed recording ≥2, 3, and 4% (ADI2, 3, and 4. The ADI2, 3, and 4 cutoff points that better discriminated between subjects with or without OSAS arose from the receiver-operator characteristics (ROCs curve analysis. OSAS was defined as a respiratory disturbance index (RDI ≥ 5. Results. 101 patients were included (77 men, mean age 52, median RDI 22.6, median BMI 27.4 kg/m2. The area under the ROCs curves (AUC-ROCs of ADI2, 3, and 4 with different data storage rates were similar (AUC-ROCs with data storage rates of 0.25/0.5/1 Hz: ADI2: 0.958/0.948/0.965, ADI3: 0.961/0.95/0.966, and ADI4: 0.957/0.949/0.963, P NS. Conclusions. The ability of WristOx 3100 to detect patients with OSAS was not affected by the data storage rate of the oxygen saturation signal. Both memory capacity of 0.25, 0.5, or 1 Hz showed a similar performance for the diagnosis of OSAS.

  9. Photoacoustic microscopy of cerebral hemodynamic and oxygen-metabolic responses to anesthetics

    Science.gov (United States)

    Cao, Rui; Li, Jun; Ning, Bo; Sun, Naidi; Wang, Tianxiong; Zuo, Zhiyi; Hu, Song

    2017-02-01

    General anesthetics are known to have profound effects on cerebral hemodynamics and neuronal activities. However, it remains a challenge to directly assess anesthetics-induced hemodynamic and oxygen-metabolic changes from the true baseline under wakefulness at the microscopic level, due to the lack of an enabling technology for high-resolution functional imaging of the awake mouse brain. To address this challenge, we have developed head-restrained photoacoustic microscopy (PAM), which enables simultaneous imaging of the cerebrovascular anatomy, total concentration and oxygen saturation of hemoglobin (CHb and sO2), and blood flow in awake mice. From these hemodynamic measurements, two important metabolic parameters, oxygen extraction fraction (OEF) and the cerebral metabolic rate of oxygen (CMRO2), can be derived. Side-by-side comparison of the mouse brain under wakefulness and anesthesia revealed multifaceted cerebral responses to isoflurane, a volatile anesthetic widely used in preclinical research and clinical practice. Key observations include elevated cerebral blood flow (CBF) and reduced oxygen extraction and metabolism.

  10. All-fiber Yb-doped fiber laser passively mode-locking by monolayer MoS2 saturable absorber

    Science.gov (United States)

    Zhang, Yue; Zhu, Jianqi; Li, Pingxue; Wang, Xiaoxiao; Yu, Hua; Xiao, Kun; Li, Chunyong; Zhang, Guangyu

    2018-04-01

    We report on an all-fiber passively mode-locked ytterbium-doped (Yb-doped) fiber laser with monolayer molybdenum disulfide (ML-MoS2) saturable absorber (SA) by three-temperature zone chemical vapor deposition (CVD) method. The modulation depth, saturation fluence, and non-saturable loss of this ML-MoS2 are measured to be 3.6%, 204.8 μJ/cm2 and 6.3%, respectively. Based on this ML-MoS2SA, a passively mode-locked Yb-doped fiber laser has been achieved at 979 nm with pulse duration of 13 ps and repetition rate of 16.51 MHz. A mode-locked fiber laser at 1037 nm is also realized with a pulse duration of 475 ps and repetition rate of 26.5 MHz. To the best of our knowledge, this is the first report that the ML-MoS2 SA is used in an all-fiber Yb-doped mode-locked fiber laser at 980 nm. Our work further points the excellent saturable absorption ability of ML-MoS2 in ultrafast photonic applications.

  11. Heart Rate and Oxygen Saturation Change Patterns During 6-min Walk Test in Subjects With Chronic Thromboembolic Pulmonary Hypertension.

    Science.gov (United States)

    Inagaki, Takeshi; Terada, Jiro; Yahaba, Misuzu; Kawata, Naoko; Jujo, Takayuki; Nagashima, Kengo; Sakao, Seiichiro; Tanabe, Nobuhiro; Tatsumi, Koichiro

    2017-12-26

    The 6-min walk test (6MWT) is commonly performed to assess functional status in patients with chronic thromboembolic pulmonary hypertension. However, changes in heart rate and oxygen saturation ( S pO 2 ) patterns during 6MWT in patients with chronic thromboembolic pulmonary hypertension remain unclear. Thirty-one subjects with chronic thromboembolic pulmonary hypertension were retrospectively evaluated to examine the relationships between the change in heart rate (Δheart rate), heart rate acceleration time, slope of heart rate acceleration, heart rate recovery during the first minute after 6MWT (HRR1), change in S pO 2 (Δ S pO 2 ), S pO 2 reduction time, and S pO 2 recovery time during 6MWT, and the severity of pulmonary hemodynamics assessed by right heart catheterization and echocardiography. Subjects with severe chronic thromboembolic pulmonary hypertension had significantly longer heart rate acceleration time (144.9 ± 63.9 s vs 96.0 ± 42.5 s, P = .033), lower Δheart rate (47.4 ± 16.9 vs 61.8 ± 13.6 beats, P = .02), and lower HRR1 (13.3 ± 9.0 beats vs 27.1 ± 9.2 beats, P pulmonary hypertension. Subjects with severe chronic thromboembolic pulmonary hypertension also had significantly longer S pO 2 reduction time (178.3 ± 70.3 s vs 134.3 ± 58.4 s, P = .03) and S pO 2 recovery time (107.6 ± 35.3 s vs 69.8 ± 32.7 s, P = .004) than did subjects with mild chronic thromboembolic pulmonary hypertension. Multivariate linear regression analysis showed only mean pulmonary arterial pressure independently was associated with heart rate acceleration time and slope of heart rate acceleration. Heart rate and S pO 2 change patterns during 6MWT is predominantly associated with pulmonary hemodynamics in subjects with chronic thromboembolic pulmonary hypertension. Evaluating heart rate and S pO 2 change patterns during 6MWT may serve a safe and convenient way to follow the change in pulmonary hemodynamics. Copyright © 2017 by Daedalus Enterprises.

  12. Solubility of C-O-H volatiles in graphite-saturated martian basalts and application to martian atmospheric evolution

    Science.gov (United States)

    Stanley, B. D.; Hirschmann, M. M.; Withers, A. C.

    2012-12-01

    The modern martian atmosphere is thin, leading to surface conditions too cold to support liquid water. Yet, there is evidence of liquid surface water early in martian history that is commonly thought to require a thick CO2 atmosphere. Our previous work follows the analysis developed by Holloway and co-workers (Holloway et al. 1992; Holloway 1998), which predicts a linear relationship between CO2 and oxygen fugacity (fO2) in graphite-saturated silicate melts. At low oxygen fugacity, the solubility of CO2 in silicate melts is therefore very low. Such low calculated solubilities under reducing conditions lead to small fluxes of CO2 associated with martian magmatism, and therefore production of a thick volcanogenic CO2 atmosphere could require a prohibitively large volume of mantle-derived magma. The key assumption in these previous calculations is that the carbonate ion is the chief soluble C-O-H species. The results of the calculations would not be affected appreciably if molecular CO2, rather than carbonate ion, were an important species, but could be entirely different if there were other appreciable C-species such as CO, carbonyl (C=O) complexes, carbide (Si-C), or CH4. Clearly, graphite-saturated experiments are required to explore how much volcanogenic C may be degassed by reduced martian lavas. A series of piston-cylinder experiments were performed on synthetic martian starting materials over a range of oxygen fugacities (IW+2.3 to IW-0.9), and at pressures of 1-3 GPa and temperatures of 1340-1600 °C in Pt-graphite double capsules. CO2 contents in experimental glasses were determined using Fourier transform infrared spectroscopy (FTIR) and range from 0.0026-0.50 wt%. CO2 solubilities change by one order of magnitude with an order of magnitude change in oxygen fugacity, as predicted by previous work. Secondary ion mass spectrometry (SIMS) determinations of C contents in glasses range from 0.0131-0.2626 wt%. C contents determined by SIMS are consistently higher

  13. Nitrogen mineralization in forestry-drained peatland soils in the Stołowe Mountains National Park (Central Sudetes Mts

    Directory of Open Access Journals (Sweden)

    Glina Bartłomiej

    2016-06-01

    Full Text Available The aim of this work was to determine the intensity of nitrogen mineralization in forestry drained ombrotrophic peatland soils in the Stołowe Mountains National Park, SW Poland. Additionally discussion about the shallow organic soils classification according to Polish Soil Classification (2011 is presented. For the study three research transects were established on forestry drained ombrotrophic peatlands in the Stołowe Mountains. Each of the transect consisted of four (site A and B or five (site C sampling plots. Sampling was conducted in the year 2012. The soil samples for the basic soil properties analysis were sampled in April, whereas undisturbed soil samples were collected in stainless steel rings (100 cm3 every 10 cm in April (spring, July (summer and October (autumn to show the seasonal dynamics of nitrogen mineralization. Statistical analysis showed that the content of N-NH4 was mainly determined by actual soil moisture and precipitation rate, whereas the content of N-NO3 was positively correlated with air temperature. Among investigated peatlands the highest concentrations of mineral nitrogen forms was observed in the Długie Mokradło bog, situated on the Skalniak Plateau-summit. Additionally, the results obtained showed that implementation of new subtype: shallow fibric peat soils (in Polish: gleby torfowe fibrowe płytkie within the type of peat soils (in polish: gleby torfowe should be considered during developing of the next update of Polish Soil Classification.

  14. Relationship Between Cerebral Oxygenation and Hemodynamic and Oxygen Transport Parameters in Surgery for Acquired Heart Diseases

    Directory of Open Access Journals (Sweden)

    A. I. Lenkin

    2012-01-01

    Full Text Available Objective: to evaluate the relationship between cerebral oxygenation and hemodynamic and oxygen transport parameters in surgical correction of concomitant acquired heart diseases. Subjects and methods. Informed consent was received from 40 patients who required surgery because of concomitant (two or more acquired heart defects. During procedure, perioperative monitoring of oxygen transport and cerebral oxygenation was performed with the aid of PiCCO2 monitor (Pulsion Medical Systems, Germany and a Fore-Sight cerebral oximeter (CASMED, USA. Anesthesia was maintained with propofol and fen-tanyl, by monitoring the depth of anesthesia. Early postoperative intensive therapy was based on the protocol for early targeted correction of hemodynamic disorders. Oxygen transport and cerebral oxygenation parameters were estimated intraopera-tively and within 24 postoperative hours. A statistical analysis including evaluation of Spearman correlations was performed with the aid of SPSS 15.0. Results. During perfusion, there was a relationship between cerebral oximetry values and hemat-ocrit levels, and oxygen partial pressure in the venous blood. Furthermore, a negative correlation between cerebral oximetry values and blood lactate levels was found 30 minutes after initiation of extracorporeal circulation (EC. During the study, there was a positive correlation between cerebral oxygenation and values of cardiac index, central venous saturation, and oxygen delivery index. There was a negative relationship between cerebral oxygenation and extravascular lung water at the beginning of surgery and a correlation between cerebral oximetry values and oxygenation index by the end of the first 24 postoperative hours. Conclusion. The cerebral oxygenation values correlate -with the main determinants of oxygen transport during EC and after cardiac surgical procedures. Cerebral oximetry may be used in early targeted therapy for the surgical correction of acquired combined

  15. 'Multi-associations': predisposed to misinterpretation of peripheral tissue oxygenation and circulation in neonates.

    Science.gov (United States)

    Pichler, Gerhard; Pocivalnik, Mirjam; Riedl, Regina; Pichler-Stachl, Elisabeth; Morris, Nicholas; Zotter, Heinz; Müller, Wilhelm; Urlesberger, Berndt

    2011-08-01

    Interpretation of peripheral circulation in ill neonates is crucial but difficult. The aim was to analyse parameters potentially influencing peripheral oxygenation and circulation. In a prospective observational cohort study in 116 cardio-circulatory stable neonates, peripheral muscle near-infrared spectroscopy (NIRS) with venous occlusion was performed. Tissue oxygenation index (TOI), mixed venous oxygenation (SvO(2)), fractional oxygen extraction (FOE), fractional tissue oxygen extraction (FTOE), haemoglobin flow (Hbflow), oxygen delivery (DO(2)), oxygen consumption (VO(2)), and vascular resistance (VR) were assessed. Correlation coefficients between NIRS parameters and demographic parameters (gestational age, birth weight, age, actual weight, diameter of calf, subcutaneous adipose tissue), monitoring parameters (heart rate, arterial oxygen saturation (SaO(2)), mean blood pressure (MAP), core/peripheral temperature, central/peripheral capillary refill time) and laboratory parameters (haemoglobin concentration (Hb-blood), pCO(2)) were calculated. All demographic parameters except for Hbflow and DO(2) correlated with NIRS parameters. Heart rate correlated with TOI, SvO(2), VO(2) and VR. SaO(2) correlated with FOE/FTOE. MAP correlated with Hbflow, DO(2), VO(2) and VR. Core temperature correlated with FTOE. Peripheral temperature correlated with all NIRS parameters except VO(2). Hb-blood correlated with FOE and VR. pCO(2) levels correlated with TOI and SvO(2). The presence of multiple interdependent factors associated with peripheral oxygenation and circulation highlights the difficulty in interpreting NIRS data. Nevertheless, these findings have to be taken into account when analysing peripheral oxygenation and circulation data.

  16. Oxygen Effects in Anaerobic Digestion

    Directory of Open Access Journals (Sweden)

    Deshai Botheju

    2009-10-01

    Full Text Available Interaction of free oxygen in bio-gasification is a sparsely studied area, apart from the common argument of oxygen being toxic and inhibitory for anaerobic micro-cultures. Some studies have, however, revealed increased solubilisation of organic matter in the presence of some free oxygen in anaerobic digestion. This article analyses these counterbalancing phenomena with a mathematical modelling approach using the widely accepted biochemical model ADM 1. Aerobic oxidation of soluble carbon and inhibition of obligatory anaerobic organisms are modelled using standard saturation type kinetics. Biomass dependent first order hydrolysis kinetics is used to relate the increased hydrolysis rate with oxygen induced increase in biomass growth. The amended model, ADM 1-Ox (oxygen, has 25 state variables and 22 biochemical processes, presented in matrix form. The computer aided simulation tool AQUASIM 2.1 is used to simulate the developed model. Simulation predictions are evaluated against experimental data obtained using a laboratory batch test array comprising miniature anaerobic bio-reactors of 100 ml total volume each, operated under different initial air headspaces giving rise to the different oxygen loading conditions. The reactors were initially fed with a glucose solution and incubated at 35 Celsius, for 563 hours. Under the oxygen load conditions of 22, 44 and 88 mg/L, the ADM1-Ox model simulations predicted the experimental methane potentials quite adequately. Both the experimental data and the simulations suggest a linear reduction of methane potential with respect to the increase in oxygen load within this range.

  17. Description of saturation curves and boiling process of dry air

    Directory of Open Access Journals (Sweden)

    Vestfálová Magda

    2018-01-01

    Full Text Available Air is a mixture of gases forming the gas wrap of Earth. It is formed by dry air, moisture and other pollutants. Dry air is a substance whose thermodynamic properties in gaseous state, as well as the thermodynamic properties of its main constituents in gaseous state, are generally known and described in detail in the literature. The liquid air is a bluish liquid and is industrially used to produce oxygen, nitrogen, argon and helium by distillation. The transition between the gaseous and liquid state (the condensation process, resp. boiling process, is usually displayed in the basic thermodynamic diagrams using the saturation curves. The saturation curves of all pure substances are of a similar shape. However, since the dry air is a mixture, the shapes of its saturation curves are modified relative to the shapes corresponding to the pure substances. This paper deals with the description of the dry air saturation curves as a mixture, i.e. with a description of the process of phase change of dry air (boiling process. The dry air saturation curves are constructed in the basic thermodynamic charts based on the values obtained from the literature. On the basis of diagrams, data appearing in various publications are interpreted and put into context with boiling process of dry air.

  18. An algorithm for sensing venous oxygenation using ultrasound-modulated light enhanced by microbubbles

    Science.gov (United States)

    Honeysett, Jack E.; Stride, Eleanor; Deng, Jing; Leung, Terence S.

    2012-02-01

    Near-infrared spectroscopy (NIRS) can provide an estimate of the mean oxygen saturation in tissue. This technique is limited by optical scattering, which reduces the spatial resolution of the measurement, and by absorption, which makes the measurement insensitive to oxygenation changes in larger deep blood vessels relative to that in the superficial tissue. Acousto-optic (AO) techniques which combine focused ultrasound (US) with diffuse light have been shown to improve the spatial resolution as a result of US-modulation of the light signal, however this technique still suffers from low signal-to-noise when detecting a signal from regions of high optical absorption. Combining an US contrast agent with this hybrid technique has been proposed to amplify an AO signal. Microbubbles are a clinical contrast agent used in diagnostic US for their ability to resonate in a sound field: in this work we also make use of their optical scattering properties (modelled using Mie theory). A perturbation Monte Carlo (pMC) model of light transport in a highly absorbing blood vessel containing microbubbles surrounded by tissue is used to calculate the AO signal detected on the top surface of the tissue. An algorithm based on the modified Beer-Lambert law is derived which expresses intravenous oxygen saturation in terms of an AO signal. This is used to determine the oxygen saturation in the blood vessel from a dual wavelength microbubble-contrast AO measurement. Applying this algorithm to the simulation data shows that the venous oxygen saturation is accurately recovered, and this measurement is robust to changes in the oxygenation of the superficial tissue layer.

  19. Electric conductivity for laboratory and field monitoring of induced partial saturation (IPS) in sands

    Science.gov (United States)

    Kazemiroodsari, Hadi

    Liquefaction is loss of shear strength in fully saturated loose sands caused by build-up of excess pore water pressure, during moderate to large earthquakes, leading to catastrophic failures of structures. Currently used liquefaction mitigation measures are often costly and cannot be applied at sites with existing structures. An innovative, practical, and cost effective liquefaction mitigation technique titled "Induced Partial Saturation" (IPS) was developed by researchers at Northeastern University. The IPS technique is based on injection of sodium percarbonate solution into fully saturated liquefaction susceptible sand. Sodium percarbonate dissolves in water and breaks down into sodium and carbonate ions and hydrogen peroxide which generates oxygen gas bubbles. Oxygen gas bubbles become trapped in sand pores and therefore decrease the degree of saturation of the sand, increase the compressibility of the soil, thus reduce its potential for liquefaction. The implementation of IPS required the development and validation of a monitoring and evaluation technique that would help ensure that the sands are indeed partially saturated. This dissertation focuses on this aspect of the IPS research. The monitoring system developed was based on using electric conductivity fundamentals and probes to detect the transport of chemical solution, calculate degree of saturation of sand, and determine the final zone of partial saturation created by IPS. To understand the fundamentals of electric conductivity, laboratory bench-top tests were conducted using electric conductivity probes and small specimens of Ottawa sand. Bench-top tests were used to study rate of generation of gas bubbles due to reaction of sodium percarbonate solution in sand, and to confirm a theory based on which degree of saturation were calculated. In addition to bench-top tests, electric conductivity probes were used in a relatively large sand specimen prepared in a specially manufactured glass tank. IPS was

  20. Oxygen nonstoichiometry and defects in Mn-doped Gd2Ti2O7+x

    International Nuclear Information System (INIS)

    Porat, O.; Tuller, H.L.

    1996-01-01

    The oxygen nonstoichiometry in Mn-doped Gd 2 Ti 2 O 7 , Gd 2 (Ti 0.975 Mn 0.025 ) 2 O 7+x , was measured electrochemically, as a function of temperature and oxygen partial pressure, with the aid of an oxygen titration cell. The analysis of the data shows that the defect equilibrium can be described by considering the dominant point defects to be neutral oxygen interstitials, doubly charged oxygen vacancies, and trivalent and quadrivalent Mn ions substituted in the Ti sites. The enthalpies for the formation of neutral oxygen interstitials and trivalent Mn are determined

  1. Analysis of γ-ray irradiated pasteurized agaricus (Agaricus blazei Murill) by ESR in oxygen-free atmosphere

    International Nuclear Information System (INIS)

    Kemeya, Hiromi; Ukai, Mitsuko

    2007-01-01

    Agaricus (Agaricus blazei Murill) is one of a popular crude drug in Japan and East Asia countries. The crude drugs originating from natural raw products are easy to be contaminated by microorganism. Radiation method has been introduced as the sterilization technology for crude drugs. ESR has been used for the detection of radicals in irradiated drugs. Using ESR, we detected radical species in Agaricus before and after the gamma ray pasteurization. The ESR spectrum consists of a broad sextet centered at g=2.0, a singlet at same g-value and a singlet at g=4.0. We found that relaxation times of radicals in Agaricus varied by the presence of oxygen. Upon substitution of air by Ar, i.e., the absent of oxygen in the ESR sample tube, the T 1 value became 10 times larger than the presence of oxygen. Accordingly, the progressive saturation curve indicates more immediate saturation under the Ar than air atmosphere. Radicals, produced by the γ-ray irradiation to Agaricus, are very sensitive to oxygen. We concluded that ESR spectrum of irradiated Agaricus sample in the absence of oxygen is useful for the detection of dose level of γ-ray irradiation. (author)

  2. The evaluation of fat saturation fast spin-echo T2W1 for patients with acute spinal trauma

    International Nuclear Information System (INIS)

    Kim, Sung Gyu; Lee, Chang Jun; Lee, Myung Joon; Kang, Ik Won; Yoo, Jeong Hyun

    2002-01-01

    To determine the usefulness of fat saturation fast spin-echo T2W1 for patients with mild acute trauma of the spine. Between July 1998 and June 2002, 36 patients with acute spinal trauma underwent MRI within four months of injury. One, whose clinal symptoms indicated neurological paralysis, was excluded form our study. A superconductive 1.0-T MRI scanner was used, and conventional T1W1, T2W1, and additional fat-saturation fast spin-echo T2W1 were performed. Two radiologists compared conventional T2-weighted sagittal imaging and fat-saturation T2-weighted sagittal imaging in terms of the extension of increased high signal intensities in soft tissue and vertebral bodies, bone marrow signal change, disk herniation, and signal change of the disk. The detection rate of focal high signal intensities in soft tissue and bone marrow was significantly higher at fat-saturation fast spin-echo T2W1 than at conventional T2W1. Fat-saturation fast spin-echo T2W1 is useful for the evaluation of patients with mild acute spinal trauma without neurological impairment

  3. Monitoring Cerebral and Renal Oxygenation Status during Neonatal Digestive Surgeries Using Near Infrared Spectroscopy

    Directory of Open Access Journals (Sweden)

    Jonathan Beck

    2017-06-01

    Full Text Available BackgroundDepending on the initial pathology, hypovolemia, intra-abdominal hypertension, and sepsis are often encountered in neonatal digestive surgery. Accurate newborn monitoring during and after surgery is essential to adapt resuscitation protocols. Near infrared spectroscopy (NIRS is non-invasive and can detect hypoperfusion which indicates a low circulatory blood flow, regardless of the cause.ObjectiveEvaluating changes in cerebral and renal regional oxygen saturation during neonatal digestive surgeries, conducted according to normal practices, with commonly used monitoring parameters. Analyzing retrospectively the inter-relationships between NIRS values and mean arterial pressure (MAP values as well as pre-ductal SpO2.MethodsProspective, descriptive, monocentric study. All neonates referred for surgery were included. NIRS allows the measurement of cerebral and renal oxygenation fluctuations, as well as calculating difference in intraoperative and postoperative values.ResultsNineteen patients were included. Cerebral regional oxygen saturation (C rSO2 values were stable while renal regional oxygen saturation (R rSO2 values tended to decrease with time during surgery. Indeed, 72% of rSO2 decline episodes occurred after the first 30 min of surgery, without any significant statistical differences for the next 90 min of surgery. After surgery, the lowest average C and R rSO2 values were evidenced during the first 6 h, with 60% of C rSO2 and R rSO2 anomalies occurring in that time frame. There was no significant statistical difference observed in the following 18 h. There was a significant correlation between R rSO2 and SpO2 values (p < 0.01, but not with C rSO2 values. There was no correlation with the MAP either for the C rSO2 values or R rSO2 ones.ConclusionNIRS is a promising non-invasive bedside tool to monitor cerebral and tissue perfusion, analyzing tissue microcirculation. NIRS has its interest to guide neonatal digestive

  4. Roughness development in the depth profiling with 500 eV O2+ beam with the combination of oxygen flooding and sample rotation

    International Nuclear Information System (INIS)

    Gui, D.; Xing, Z.X.; Huang, Y.H.; Mo, Z.Q.; Hua, Y.N.; Zhao, S.P.; Cha, L.Z.

    2008-01-01

    Roughness development is one of the most often addressed issues in the secondary ion mass spectrometry (SIMS) ultra-shallow depth profiling. The effect of oxygen flooding pressure on the roughness development has been investigated under the bombardment of 500 eV O 2 + beam with simultaneous sample rotation. Oxygen flooding had two competing effects on the surface roughening, i.e., enhancement of initiating roughening and suppression of roughening development, which were suggested to be described by the onset depth z on and transient width w tr of surface roughening. Both z on and w tr decreased as oxygen flooding pressure increased. As the result, surface roughening was most pronounced at the intermediate pressure from 4.4E-5 Pa to 5.8E-5 Pa. The surface roughening is negligible while without flooding or with flooding at the saturated pressure. No flooding is preferable for depth profiling ultra-shallow B implantation because of the better B profile shape and short analysis time

  5. Automated oxygen titration and weaning with FreeO2 in patients with acute exacerbation of COPD: a pilot randomized trial

    Directory of Open Access Journals (Sweden)

    Lellouche F

    2016-08-01

    Full Text Available François Lellouche,1 Pierre-Alexandre Bouchard,1 Maude Roberge,1 Serge Simard,1,2 Erwan L’Her,1,3 François Maltais,1 Yves Lacasse1 1Research Centre, 2Biostatistics Department, Quebec Heart and Lung Institute, Laval University, 3Emergency Medicine, Hôtel-Dieu de Lévis, Laval University, Quebec City, QC, Canada Introduction: We developed a device (FreeO2 that automatically adjusts the oxygen flow rates based on patients’ needs, in order to limit hyperoxia and hypoxemia and to automatically wean them from oxygen. Objective: The aim of this study was to evaluate the feasibility of using FreeO2 in patients hospitalized in the respiratory ward for an acute exacerbation of COPD. Methods: We conducted a randomized controlled trial comparing FreeO2 vs manual oxygen titration in the respiratory ward of a university hospital. We measured the perception of appropriateness of oxygen titration and monitoring in both groups by nurses and attending physicians using a Likert scale. We evaluated the time in the target range of oxygen saturation (SpO2 as defined for each patient by the attending physician, the time with severe desaturation (SpO2 <85%, and the time with hyperoxia (SpO2 >5% above the target. We also recorded length of stay, intensive care unit admissions, and readmission rate. Fifty patients were randomized (25 patients in both groups; mean age: 72±8 years; mean forced expiratory volume in 1 second: 1.00±0.49 L; and mean initial O2 flow 2.0±1.0 L/min. Results: Nurses and attending physicians felt that oxygen titration and monitoring were equally appropriate with both O2 administration systems. The percentage of time within the SpO2 target was significantly higher with FreeO2, and the time with severe desaturation and hyperoxia was significantly reduced with FreeO2. Time from study inclusion to hospital discharge was 5.8±4.4 days with FreeO2 and 8.4±6.0 days with usual oxygen administration (P=0.051. Conclusion: FreeO2 was deemed as an

  6. Au-MnO{sub 2}/MWNT and Au-ZnO/MWNT as oxygen reduction reaction electrocatalyst for polymer electrolyte membrane fuel cell

    Energy Technology Data Exchange (ETDEWEB)

    Imran Jafri, Razack; Sujatha, N.; Ramaprabhu, S. [Alternative Energy and Nanotechnology Laboratory (AENL), Nano Functional Materials Technology Centre (NFMTC), Department of Physics, Indian Institute of Technology Madras, Chennai (India); Rajalakshmi, N. [Center for Fuel Cell Technology (ARCI), Madavakkam, Chennai (India)

    2009-08-15

    Bi-functional catalysts based on Au supported on oxide based nanomaterials for use in fuel cells were evaluated by electrochemical methods for oxygen reduction reaction (ORR) in Polymer Electrolyte Membrane Fuel Cell (PEMFC). Metal oxide coated multi walled carbon nanotubes (MWNTs) (MnO{sub 2}/MWNT and ZnO/MWNT) were prepared by reduction of potassium permanganate and oxidation of Zn powder on MWNT surface respectively. Au-MnO{sub 2}/MWNT and Au-ZnO/MWNT were prepared by chemical reduction of chloroauric acid on MnO{sub 2}/MWNT and ZnO/MWNT. The samples were characterized and linear sweep voltammetric studies were performed in N{sub 2} saturated, O{sub 2} saturated and methanol containing 1 M KOH solution and the results have been discussed. A single fuel cell was also constructed using Au-MnO{sub 2}/MWNT and Au-ZnO/MWNT as ORR electrocatalysts. A maximum power density of 45 mW/cm{sup 2} and 56 mW/cm{sup 2} was obtained with Au-MnO{sub 2}/MWNT and Au-ZnO/MWNT respectively. Additionally, the methanol tolerance of these electrocatalysts has been investigated and results have been discussed. (author)

  7. Oxygen redistribution in (UCe)Osub(2-x)

    International Nuclear Information System (INIS)

    Guedeney, Philippe.

    1983-01-01

    Redistribution of oxygen has been investigated in (Usub(0,7)Cesub(0,3))Osub(2-x) mixed oxide subjected to a temperature gradient in laboratory experiments, in order to apply the results to the nuclear fuel (UPu)Osub(2-x). Cylindrical sintered oxide specimens were exposed to temperature up to 1300 0 C with a longitudinal thermal gradient of about 400 0 C/cm. The most interesting feature of the experimental set-up is a solid-state electrochemical gauge (ThO 2 - Y 2 O 3 ), placed in the cold part of the sample which allows a continuous measurement of the oxygen activity. The experiments showed a fast oxygen migration down the thermal gradient. The calculations performed with a model based on solid-state thermodiffusion are in good agreement with experimental results. The heat of transport Q measured for bare samples reaches (7.2+-0.5)-kcal/mole. When the sample is coated with a tight fitting metallic cladding, an extra term Qe has to be added to the heat of transport Qe. This was interpreted as an electrotransport phenomena. On the same basis, calculations applied to radial oxygen redistribution in (UPu)Osub(2-x) seem to be adequate at least during the first stage of irradiation, taking Q=(20+-5)kcal/mole [fr

  8. Variation of saturation effect in the ionospheric F2 critical frequency at low latitude

    Science.gov (United States)

    Ikubanni, S. O.; Adeniyi, J. O.

    2013-08-01

    Saturation in the dependence of foF2 on solar flux is a phenomenon more pronounced in the equatorial ionization anomaly region. The phenomenon was observed in the relationship between the F2 critical frequency (foF2) and any solar indices. Using a two-segmented regression fit on data from an African low latitude station (Geographical Latitude 12.4°N; Geomagnetic latitude 3.5°N), saturation features from the dependence of foF2 on solar radio flux (F10.7) was studied. Diurnal and seasonal variation were studied for the first time in this low latitude region of the African sector. Significant variations were observed, especially in the solstices. It was observed that saturation effect is closely related to the hourly F2 critical frequency and these results were compared with those from Asian, Australian and the American sectors. The diurnal and seasonal variations find their explanations in the photo-ionization process, the fountain effect, and the pre-reversal enhancement while the seasonal variation was attributed to both the ion drift and thermospheric circulation. Future work with larger volume of data is expected to validate the observations from this study.

  9. The evaluation of fat saturation fast spin-echo T2WI for patients with acute spinal trauma

    International Nuclear Information System (INIS)

    Kim, Sung Gyu; Lee, Chang Jun; Lee, Myung Joon; Kang, Ik Won; Yoo, Jeong Hyun

    2002-01-01

    To determine the usefulness of fat saturation fast spin-echo T2WI for patients with mild acute trauma of the spine. Between July 1998 and June 2002, 36 patients with acute spinal trauma underwent MRI within four months of injury. One, whose clinal symptoms indicated neurological paralysis, was excluded form our study. A superconductive 1.0-T MRI scanner was used, and conventional T1W1, T2W1, and additional fat-saturation fast spin-echo T2W1 were performed. Two radiologists compared conventional T2-weighted sagittal imaging and fat-saturation T2-weighted sagittal imaging in terms of the extension of increased high signal intensities in soft tissue and vertebral bodies, bone marrow signal change, disk herniation, and signal change of the disk. The detection rate of focal high signal intensities in soft tissue and bone marrow was significantly higher at fat-saturation fast spin-echo T2W1 is useful the evaluation of patients with mild acute spinal trauma without neurological impairment

  10. ANESTHETIC INDUCTION AND RECOVERY PARAMETERS IN BEARDED DRAGONS (POGONA VITTICEPS): COMPARISON OF ISOFLURANE DELIVERED IN 100% OXYGEN VERSUS 21% OXYGEN.

    Science.gov (United States)

    O, Odette; Churgin, Sarah M; Sladky, Kurt K; Smith, Lesley J

    2015-09-01

    Inland bearded dragons (Pogona vitticeps, n=6) were anesthetized for 1 hr using isoflurane in either 100% oxygen or 21% oxygen (FI 21; medical-grade room air). Parameters of anesthetic depth were recorded throughout both induction and recovery by an observer blinded to the fraction of inspired oxygen (FiO2), including the loss and return of withdrawal and righting reflexes, muscle tone, ability to intubate or extubate, and return to spontaneous respiration. Physiologic data were recorded every 5 min throughout the anesthetic procedures, including heart rate, body temperature, end-tidal CO2, hemoglobin oxygen saturation (SpO2), and percent expired isoflurane. Lizards were subjected to application of a noxious stimulus (needle stick) at 0, 30, and 60 min, and responses recorded. Following a minimum 7-day washout period, the experiment was repeated with each lizard subjected to the other protocol in a randomized, complete crossover design. The only statistically significant difference was a lower mean SpO2 in the group inspiring 21% oxygen (P<0.0020). No statistically significant differences were detected in any parameters during induction or recovery; however, all values were uniformly shorter for the FI 21 group, indicating a possible clinically significant difference. A larger sample size may have detected statistically significant differences. Further studies are needed to evaluate these effects in other reptile species and with the concurrent use of injectable anesthetic and analgesic drugs.

  11. The kinetics of oxygen and SO2 consumption by red wines. What do they tell about oxidation mechanisms and about changes in wine composition?

    Science.gov (United States)

    Carrascón, Vanesa; Vallverdú-Queralt, Anna; Meudec, Emmanuelle; Sommerer, Nicolas; Fernandez-Zurbano, Purificación; Ferreira, Vicente

    2018-02-15

    This work seeks to understand the kinetics of O 2 and SO 2 consumption of air-saturated red wine as a function of its chemical composition, and to describe the chemical changes suffered during the process in relation to the kinetics. Oxygen Consumption Rates (OCRs) are faster with higher copper and epigallocatechin contents and with higher absorbance at 620nm and slower with higher levels of gallic acid and catechin terminal units in tannins. Acetaldehyde Reactive Polyphenols (ARPs) may be key elements determining OCRs. It is confirmed that SO 2 is poorly consumed in the first saturation. Phenylalanine, methionine and maybe, cysteine, seem to be consumed instead. A low SO 2 consumption is favoured by low levels of SO 2 , by a low availability of free SO 2 caused by a high anthocyanin/tannin ratio, and by a polyphenolic profile poor in epigallocatechin and rich in catechin-rich tannins. Wines consuming SO 2 efficiently consume more epigallocatechin, prodelphinidins and procyanidins. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Oxygen pressure-tuned epitaxy and magnetic properties of magnetite thin films

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Junran [Jiangsu Provincial Key Laboratory of Advanced Photonic and Electronic Materials, Jiangsu Provincial Key Laboratory for Nanotechnology, Collaborative Innovation Center of Advanced Microstructures, School of Electronic Science and Engineering, Nanjing University, Nanjing 210093 (China); Liu, Wenqing [York-Nanjing Joint Centre (YNJC) for Spintronics and Nanoengineering, Department of Electronics, The University of York, YO10 3DD (United Kingdom); Zhang, Minhao; Zhang, Xiaoqian; Niu, Wei; Gao, Ming [Jiangsu Provincial Key Laboratory of Advanced Photonic and Electronic Materials, Jiangsu Provincial Key Laboratory for Nanotechnology, Collaborative Innovation Center of Advanced Microstructures, School of Electronic Science and Engineering, Nanjing University, Nanjing 210093 (China); Wang, Xuefeng, E-mail: xfwang@nju.edu.cn [Jiangsu Provincial Key Laboratory of Advanced Photonic and Electronic Materials, Jiangsu Provincial Key Laboratory for Nanotechnology, Collaborative Innovation Center of Advanced Microstructures, School of Electronic Science and Engineering, Nanjing University, Nanjing 210093 (China); Du, Jun [School of Physics, Nanjing University, Nanjing 210093 (China); Zhang, Rong [Jiangsu Provincial Key Laboratory of Advanced Photonic and Electronic Materials, Jiangsu Provincial Key Laboratory for Nanotechnology, Collaborative Innovation Center of Advanced Microstructures, School of Electronic Science and Engineering, Nanjing University, Nanjing 210093 (China); Xu, Yongbing, E-mail: ybxu@nju.edu.cn [Jiangsu Provincial Key Laboratory of Advanced Photonic and Electronic Materials, Jiangsu Provincial Key Laboratory for Nanotechnology, Collaborative Innovation Center of Advanced Microstructures, School of Electronic Science and Engineering, Nanjing University, Nanjing 210093 (China); York-Nanjing Joint Centre (YNJC) for Spintronics and Nanoengineering, Department of Electronics, The University of York, YO10 3DD (United Kingdom)

    2017-06-15

    Highlights: • Quasi-2D Fe{sub 3}O{sub 4} films were obtained by PLD. • RHEED under different oxygen pressure were observed. • Influence of oxygen pressure on Fe{sub 3}O{sub 4} films were investigated. • Epitaxy and magnetic properties were tuned by oxygen pressure. • The ratio of Fe{sup 2+}/Fe{sup 3+} fitted by XPS is the tuned factor of M{sub s}. - Abstract: Quasi-two-dimensional magnetite epitaxial thin films have been synthesized by pulsed laser deposition technique at various oxygen pressures. The saturation magnetizations of the magnetite films were found to decrease from 425 emu/cm{sup 3}, which is close to the bulk value, to 175 emu/cm{sup 3} as the growth atmospheres varying from high vacuum (∼1 × 10{sup −8} mbar) to oxygen pressure of 1 × 10{sup −3} mbar. The ratio of the Fe{sup 3+} to Fe{sup 2+} increases from 2 to 2.7 as oxygen pressure increasing shown by XPS fitting, which weakens the net magnetic moment generated by Fe{sup 2+} at octahedral sites as the spins of the Fe{sup 3+} ions at octahedral and tetrahedral sites are aligned in antiparallel. The results offer direct experimental evidence of the influence to the Fe{sup 3+}/Fe{sup 2+} ratio and the magnetic moment in magnetite epitaxy films by oxygen pressure, which is significant for spintronic applications.

  13. Oxygen potentials, oxygen diffusion coefficients and defect equilibria of nonstoichiometric (U,Pu)O{sub 2±x}

    Energy Technology Data Exchange (ETDEWEB)

    Kato, Masato, E-mail: kato.masato@jaea.go.jp [Fukushima Fuels and Materials Department, Japan Atomic Energy Agency, 4002 Narita-chou, O-arai machi, Ibaraki 311-1919 (Japan); Fast Reactor Fuel Cycle Technology Development Division, Japan Atomic Energy Agency, 4-33 Muramatsu Tokai-mura, Ibaraki 319-1194 (Japan); Watanabe, Masashi [Fukushima Fuels and Materials Department, Japan Atomic Energy Agency, 4002 Narita-chou, O-arai machi, Ibaraki 311-1919 (Japan); Fast Reactor Fuel Cycle Technology Development Division, Japan Atomic Energy Agency, 4-33 Muramatsu Tokai-mura, Ibaraki 319-1194 (Japan); Matsumoto, Taku; Hirooka, Shun; Akashi, Masatoshi [Fast Reactor Fuel Cycle Technology Development Division, Japan Atomic Energy Agency, 4-33 Muramatsu Tokai-mura, Ibaraki 319-1194 (Japan)

    2017-04-15

    Oxygen potential of (U,Pu)O{sub 2±x} was evaluated based on defect chemistry using an updated experimental data set. The relationship between oxygen partial pressure and deviation x in (U,Pu)O{sub 2±x} was analyzed, and equilibrium constants of defect formation were determined as functions of Pu content and temperature. Brouwer's diagrams were constructed using the determined equilibrium constants, and a relational equation to determine O/M ratio was derived as functions of O/M ratio, Pu content and temperature. In addition, relationship between oxygen potential and oxygen diffusion coefficients were described. - Highlights: •Brouwer’s diagrams for (U,Pu)O2 were constructed using the updated oxygen potential experimental data set. •Equilibrium constants of defect formation were determined as functions of Pu content and temperature. •Oxygen potential, oxygen diffusion coefficients, point defect concentration were described as functions of O/M ratio, Pu content and temperature.

  14. Experimental comparison among hydrocarbon and oxygenated compounds for their elimination by three-way automotive catalysts

    International Nuclear Information System (INIS)

    Bart, J.M.; Prigent, M.F.

    1992-01-01

    Many hydrocarbon species are present in automotive exhaust gases, and three-way Pt-Rh catalysts are commonly used for their elimination. However, most published work on individual hydrocarbon conversion concerns their oxidation in simulated exhaust gases with excess oxygen. This paper reports that this study was therefore undertaken to determine the reactivity of saturated alkanes, olefins, acetylene, aromatics, alcohols or various other oxygenated compounds in steady state conditions with synthetic exhaust gases near stoichiometry. In a first series of measurements, conversion rates were determined as a function of temperature at stoichiometry. The partial pressure effect of O 2 , NO and H 2 O was then determined at constant temperature in the region of catalyst light-off. NO and mainly O 2 were shown to have a negative effect on the first terms of saturated alkane conversion under lean conditions. Water vapor has a positive effect in rich conditions (without SO 2 ), but is more pronounced for Pt-Rh than for a Pt catalyst. Finally, the role played by SO 2 in hydrocarbon conversion was evaluated

  15. Effects of carbon dioxide insufflation on regional cerebral oxygenation during laparoscopic surgery in children: a prospective study.

    Science.gov (United States)

    Tuna, Ayca Tas; Akkoyun, Ibrahim; Darcin, Sevtap; Palabiyik, Onur

    2016-01-01

    Laparoscopic surgery has become a popular surgical tool when compared to traditional open surgery. There are limited data on pediatric patients regarding whether pneumoperitoneum affects cerebral oxygenation although end-tidal CO2 concentration remains normal. Therefore, this study was designed to evaluate the changes of cerebral oxygen saturation using near-infrared spectroscope during laparoscopic surgery in children. The study comprised forty children who were scheduled for laparoscopic (Group L, n=20) or open (Group O, n=20) appendectomy. Hemodynamic variables, right and left regional cerebral oxygen saturation (RrSO2 and LrSO2), fraction of inspired oxygen, end-tidal carbon dioxide pressure (PETCO2), peak inspiratory pressure (Ppeak), respiratory minute volume, inspiratory and end-tidal concentrations of sevoflurane and body temperature were recorded. All parameters were recorded after anesthesia induction and before start of surgery (T0, baseline), 15min after start of surgery (T1), 30min after start of surgery (T2), 45min after start of surgery (T3), 60min after start of surgery (T4) and end of the surgery (T5). There were progressive decreases in both RrSO2 and LrSO2 levels in both groups, which were not statistically significant at T1, T2, T3, T4. The RrSO2 levels of Group L at T5 were significantly lower than that of Group O. One patient in Group L had an rSO2 value <80% of the baseline value. Carbon dioxide insufflation during pneumoperitoneum in pediatric patients may not affect cerebral oxygenation under laparoscopic surgery. Copyright © 2015 Sociedade Brasileira de Anestesiologia. Published by Elsevier Editora Ltda. All rights reserved.

  16. [Effects of carbon dioxide insufflation on regional cerebral oxygenation during laparoscopic surgery in children: a prospective study].

    Science.gov (United States)

    Tuna, Ayca Tas; Akkoyun, Ibrahim; Darcin, Sevtap; Palabiyik, Onur

    2016-01-01

    Laparoscopic surgery has become a popular surgical tool when compared to traditional open surgery. There are limited data on pediatric patients regarding whether pneumoperitoneum affects cerebral oxygenation although end-tidal CO2 concentration remains normal. Therefore, this study was designed to evaluate the changes of cerebral oxygen saturation using near-infrared spectroscope during laparoscopic surgery in children. The study comprised forty children who were scheduled for laparoscopic (Group L, n=20) or open (Group O, n=20) appendectomy. Hemodynamic variables, right and left regional cerebral oxygen saturation (RrSO2 and LrSO2), fraction of inspired oxygen, end-tidal carbon dioxide pressure (PETCO2), peak inspiratory pressure (Ppeak), respiratory minute volume, inspiratory and end-tidal concentrations of sevoflurane and body temperature were recorded. All parameters were recorded after anesthesia induction and before start of surgery (T0, baseline), 15min after start of surgery (T1), 30min after start of surgery (T2), 45min after start of surgery (T3), 60min after start of surgery (T4) and end of the surgery (T5). There were progressive decreases in both RrSO2 and LrSO2 levels in both groups, which were not statistically significant at T1, T2, T3, T4. The RrSO2 levels of Group L at T5 were significantly lower than that of Group O. One patient in Group L had an rSO2 value <80% of the baseline value. Carbon dioxide insufflation during pneumoperitoneum in pediatric patients may not affect cerebral oxygenation under laparoscopic surgery. Copyright © 2015 Sociedade Brasileira de Anestesiologia. Publicado por Elsevier Editora Ltda. All rights reserved.

  17. NIRS Study of the Effects of Computerized Brain Training Games for Cognitive Rehabilitation of Major Depressive Disorder Patients in Remission: A Pilot Study.

    Science.gov (United States)

    Payzieva, Shaira; Maxmudova, D

    2014-01-01

    We used functional Near-Infrared Spectroscopy (fNIRS) to estimate brain activity in Major Depressive Disorder (MDD) patients (in remission), while they played a computerized brain training games for cognitive rehabilitation. MDD is characterized by marked deterioration in affect as well as significant impairment in cognitive function. It was found, that depressed patients showed long-lasting impaired cognitive performance on cognitive demanding tasks despite significant improvement in the depression symptoms. Previous studies have shown that video games can improve cognitive functions. But assessment was made only with cognitive tests. The main objective of this research was to study the effects of brain training games on cognitive functions of MDD patients in remission with objective instrumental NIRS method. Tissue oxygen saturation (StO2) and absolute concentrations of oxyhemoglobin ([O2Hb]), deoxyhemoglobin ([HHb]) and total hemoglobin ([tHb]) were measured by functional near-infrared spectroscopy (fNIRS) - Oxyprem (BORL, Zurich, Switzerland). Preliminary results are discussed.

  18. Hierarchical saturation of soil carbon pools near a natural CO2 spring

    NARCIS (Netherlands)

    Kool, D.M.; Chung, H.; Tate, K.R.; Ross, D.J.; Newton, P.C.D.; Six, J.

    2007-01-01

    Soil has been identified as a possible carbon (C) sink to mitigate increasing atmospheric CO2 concentration. However, several recent studies have suggested that the potential of soil to sequester C is limited and that soil may become saturated with C under increasing CO2 levels. To test this concept

  19. A sensitivity analysis on seismic tomography data with respect to CO2 saturation of a CO2 geological sequestration field

    Science.gov (United States)

    Park, Chanho; Nguyen, Phung K. T.; Nam, Myung Jin; Kim, Jongwook

    2013-04-01

    Monitoring CO2 migration and storage in geological formations is important not only for the stability of geological sequestration of CO2 but also for efficient management of CO2 injection. Especially, geophysical methods can make in situ observation of CO2 to assess the potential leakage of CO2 and to improve reservoir description as well to monitor development of geologic discontinuity (i.e., fault, crack, joint, etc.). Geophysical monitoring can be based on wireline logging or surface surveys for well-scale monitoring (high resolution and nallow area of investigation) or basin-scale monitoring (low resolution and wide area of investigation). In the meantime, crosswell tomography can make reservoir-scale monitoring to bridge the resolution gap between well logs and surface measurements. This study focuses on reservoir-scale monitoring based on crosswell seismic tomography aiming describe details of reservoir structure and monitoring migration of reservoir fluid (water and CO2). For the monitoring, we first make a sensitivity analysis on crosswell seismic tomography data with respect to CO2 saturation. For the sensitivity analysis, Rock Physics Models (RPMs) are constructed by calculating the values of density and P and S-wave velocities of a virtual CO2 injection reservoir. Since the seismic velocity of the reservoir accordingly changes as CO2 saturation changes when the CO2 saturation is less than about 20%, while when the CO2 saturation is larger than 20%, the seismic velocity is insensitive to the change, sensitivity analysis is mainly made when CO2 saturation is less than 20%. For precise simulation of seismic tomography responses for constructed RPMs, we developed a time-domain 2D elastic modeling based on finite difference method with a staggered grid employing a boundary condition of a convolutional perfectly matched layer. We further make comparison between sensitivities of seismic tomography and surface measurements for RPMs to analysis resolution

  20. Large, non-saturating magnetoresistance in WTe2.

    Science.gov (United States)

    Ali, Mazhar N; Xiong, Jun; Flynn, Steven; Tao, Jing; Gibson, Quinn D; Schoop, Leslie M; Liang, Tian; Haldolaarachchige, Neel; Hirschberger, Max; Ong, N P; Cava, R J

    2014-10-09

    Magnetoresistance is the change in a material's electrical resistance in response to an applied magnetic field. Materials with large magnetoresistance have found use as magnetic sensors, in magnetic memory, and in hard drives at room temperature, and their rarity has motivated many fundamental studies in materials physics at low temperatures. Here we report the observation of an extremely large positive magnetoresistance at low temperatures in the non-magnetic layered transition-metal dichalcogenide WTe2: 452,700 per cent at 4.5 kelvins in a magnetic field of 14.7 teslas, and 13 million per cent at 0.53 kelvins in a magnetic field of 60 teslas. In contrast with other materials, there is no saturation of the magnetoresistance value even at very high applied fields. Determination of the origin and consequences of this effect, and the fabrication of thin films, nanostructures and devices based on the extremely large positive magnetoresistance of WTe2, will represent a significant new direction in the study of magnetoresistivity.

  1. Oxygen supplementation in anesthetized brown bears (Ursus arctos)-how low can you go?

    Science.gov (United States)

    Fahlman, Åsa; Arnemo, Jon M; Pringle, John; Nyman, Görel

    2014-07-01

    Hypoxemia is anticipated during wildlife anesthesia and thus should be prevented. We evaluated the efficacy of low flow rates of supplemental oxygen for improvement of arterial oxygenation in anesthetized brown bears (Ursus arctos). The study included 32 free-ranging brown bears (yearlings, subadults, and adults; body mass 12-250 kg) that were darted with medetomidine-zolazepam-tiletamine (MZT) from a helicopter in Sweden. During anesthesia, oxygen was administered intranasally from portable oxygen cylinders at different flow rates (0.5-3 L/min). Arterial blood samples were collected before (pre-O2), during, and after oxygen therapy and immediately processed with a portable analyzer. Rectal temperature, respiratory rate, heart rate, and pulse oximetry-derived hemoglobin oxygen saturation were recorded. Intranasal oxygen supplementation at the evaluated flow rates significantly increased the partial pressure of arterial oxygen (PaO2) from pre-O2 values of 9.1 ± 1.3 (6.3-10.9) kPa to 20.4 ± 6.8 (11.1-38.7) kPa during oxygen therapy. When oxygen therapy was discontinued, the PaO2 decreased to values not significantly different from the pre-O2 values. In relation to the body mass of the bears, the following oxygen flow rates are recommended: 0.5 L/min to bears bears 51-100 kg, 2 L/min to bears 101-200 kg, and 3 L/min to bears 201-250 kg. In conclusion, low flow rates of intranasal oxygen were sufficient to improve arterial oxygenation in brown bears anesthetized with MZT. Because hypoxemia quickly recurred when oxygen was discontinued, oxygen supplementation should be provided continuously throughout anesthesia.

  2. 'Multi-associations': predisposed to misinterpretation of peripheral tissue oxygenation and circulation in neonates

    International Nuclear Information System (INIS)

    Pichler, Gerhard; Pocivalnik, Mirjam; Pichler-Stachl, Elisabeth; Morris, Nicholas; Zotter, Heinz; Müller, Wilhelm; Urlesberger, Berndt; Riedl, Regina

    2011-01-01

    Interpretation of peripheral circulation in ill neonates is crucial but difficult. The aim was to analyse parameters potentially influencing peripheral oxygenation and circulation. In a prospective observational cohort study in 116 cardio-circulatory stable neonates, peripheral muscle near-infrared spectroscopy (NIRS) with venous occlusion was performed. Tissue oxygenation index (TOI), mixed venous oxygenation (SvO 2 ), fractional oxygen extraction (FOE), fractional tissue oxygen extraction (FTOE), haemoglobin flow (Hbflow), oxygen delivery (DO 2 ), oxygen consumption (VO 2 ), and vascular resistance (VR) were assessed. Correlation coefficients between NIRS parameters and demographic parameters (gestational age, birth weight, age, actual weight, diameter of calf, subcutaneous adipose tissue), monitoring parameters (heart rate, arterial oxygen saturation (SaO 2 ), mean blood pressure (MAP), core/peripheral temperature, central/peripheral capillary refill time) and laboratory parameters (haemoglobin concentration (Hb-blood), pCO 2 ) were calculated. All demographic parameters except for Hbflow and DO 2 correlated with NIRS parameters. Heart rate correlated with TOI, SvO 2 , VO 2 and VR. SaO 2 correlated with FOE/FTOE. MAP correlated with Hbflow, DO 2 , VO 2 and VR. Core temperature correlated with FTOE. Peripheral temperature correlated with all NIRS parameters except VO 2 . Hb-blood correlated with FOE and VR. pCO 2 levels correlated with TOI and SvO 2 . The presence of multiple interdependent factors associated with peripheral oxygenation and circulation highlights the difficulty in interpreting NIRS data. Nevertheless, these findings have to be taken into account when analysing peripheral oxygenation and circulation data

  3. The effects of swimming exercise and dissolved oxygen on growth performance, fin condition and precocious maturation of early-rearing Atlantic salmon Salmo salar

    Science.gov (United States)

    Atlantic salmon fry were stocked into twelve circular 0.5 m3 tanks in a flow-through system and exposed to either high (1.5-2 body-lengths per second, or BL/s) or low (less than 0.5 BL/s) swimming speeding and high (100% saturation) or low (70% saturation) dissolved oxygen (DO) while being raised fr...

  4. TH-AB-209-05: Validating Hemoglobin Saturation and Dissolved Oxygen in Tumors Using Photoacoustic Computed Tomographic Spectroscopic Imaging

    Energy Technology Data Exchange (ETDEWEB)

    Burnett, J; Sick, J; Liu, B [Purdue University, West Lafayette, IN (United States); Cao, N [University of Washington Medical Center, Seattle, WA (United States); Nakshatri, H; Mendonca, M [Indiana University - Purdue University Indianapolis, Indianapolis, IN (United States); Stantz, K [Purdue University, West Lafayette, IN (United States); Indiana University - Purdue University Indianapolis, Indianapolis, IN (United States)

    2016-06-15

    Purpose: Photoacoustic computed tomographic spectroscopy (PCT-S) provides intra-tumor measurements of oxygenation with high spatial resolution (0.2mm) and temporal fidelity (1–2 minutes) without the need for exogenous agents or ionizing radiation, thus providing a unique in vivo assay to measure SaO{sub 2} and investigate acute and chronic forms of hypoxia. The goal of this study is to validate in vivo SaO{sub 2} levels within tail artery of mice and the relationship between SaO{sub 2} and pO{sub 2} within subcutaneous breast tumors using PCT-S imaging, pulse oximetry and an OxyLite probe. Methods: A closed circuit phantom was fabricated to control blood oxygenation levels, where SaO{sub 2} was measured using a co-oximeter and pO{sub 2} using an Oxylite probe. Next, SaO{sub 2} levels within the tail arteries of mice (n=3) were measured using PCT-S and pulse oximetry while breathing high-to-low oxygen levels (6-cycles). Finally, PCT-S was used to measure SaO{sub 2} levels in MCF-7, MCF-7-VEGF165, and MDA-MB-231 xenograft breast tumors and compared to Oxylite pO{sub 2} levels values. Results: SaO{sub 2} and pO{sub 2} data obtained from the calibration phantom was fit to Hill’s equation: aO{sub 2} levels between 88 and 52% demonstrated a linear relationship (r2=0.96) and a 3.2% uncertainty between PCT-S values relative to pulse oximetry. Scatter plots of localized PCT-S measured SaO2 and Oxylite pO{sub 2} levels in MCF-7/MCF-7-VEGF165 and MDA-MD-231 breast tumors were fit to Hill’s equation: P50=17.2 and 20.7mmHg, and n=1.76 and 1.63. These results are consistent with sigmoidal form of Hill’s equation, where the lower P{sub 50} value is indicative of an acidic tumor microenvironment. Conclusion: The results demonstrate photoacoustic imaging can be used to measure SaO{sub 2} cycling and intra-tumor oxygenation, and provides a powerful in vivo assay to investigate the role of hypoxia in radiation, anti-angiogenic, and immunotherapies.

  5. Každodenní život městských protestantských komunit pozdního 18. století. Brno a nové Město na Moravě

    Czech Academy of Sciences Publication Activity Database

    Bolom-Kotari, Sixtus

    2014-01-01

    Roč. 33, č. 1 (2014), s. 269-298 ISSN 0231-7443 Institutional support: RVO:67985963 Keywords : 1781 * Brno * Nové Město na Moravě * Edict of Tolerance * Enlightenment * Protestantism Subject RIV: AB - History

  6. Oxygen isotope fractionation in the CaCO3-DIC-H2O system

    Science.gov (United States)

    Devriendt, Laurent S.; Watkins, James M.; McGregor, Helen V.

    2017-10-01

    The oxygen isotope ratio (δ18O) of inorganic and biogenic carbonates is widely used to reconstruct past environments. However, the oxygen isotope exchange between CaCO3 and H2O rarely reaches equilibrium and kinetic isotope effects (KIE) commonly complicate paleoclimate reconstructions. We present a comprehensive model of kinetic and equilibrium oxygen isotope fractionation between CaCO3 and water (αc/w) that accounts for fractionation between both (a) CaCO3 and the CO32- pool (α c / CO32-) , and (b) CO32- and water (α CO32- / w) , as a function of temperature, pH, salinity, calcite saturation state (Ω), the residence time of the dissolved inorganic carbon (DIC) in solution, and the activity of the enzyme carbonic anhydrase. The model results suggest that: (1) The equilibrium αc/w is only approached in solutions with low Ω (i.e. close to 1) and low ionic strength such as in the cave system of Devils Hole, Nevada. (2) The sensitivity of αc/w to the solution pH and/or the mineral growth rate depends on the level of isotopic equilibration between the CO32- pool and water. When the CO32- pool approaches isotopic equilibrium with water, small negative pH and/or growth rate effects on αc/w of about 1-2‰ occur where these parameters covary with Ω. In contrast, isotopic disequilibrium between CO32- and water leads to strong (>2‰) positive or negative pH and growth rate effects on α CO32-/ w (and αc/w) due to the isotopic imprint of oxygen atoms derived from HCO3-, CO2, H2O and/or OH-. (3) The temperature sensitivity of αc/w originates from the negative effect of temperature on α CO32-/ w and is expected to deviate from the commonly accepted value (-0.22 ± 0.02‰/°C between 0 and 30 °C; Kim and O'Neil, 1997) when the CO32- pool is not in isotopic equilibrium with water. (4) The model suggests that the δ18O of planktic and benthic foraminifers reflects a quantitative precipitation of DIC in isotopic equilibrium with a high-pH calcifying fluid, leading

  7. Nasal Cannula Apneic Oxygenation Prevents Desaturation During Endotracheal Intubation: An Integrative Literature Review

    Directory of Open Access Journals (Sweden)

    Bill R. Christian

    2018-02-01

    Full Text Available Patients requiring emergency airway management may be at greater risk of acute hypoxemic events because of underlying lung pathology, high metabolic demands, insufficient respiratory drive, obesity, or the inability to protect their airway against aspiration. Emergency tracheal intubation is often required before complete information needed to assess the risk of procedural hypoxia is acquired (i.e., arterial blood gas level, hemoglobin value, or chest radiograph. During pre-oxygenation, administering high-flow nasal oxygen in addition to a non-rebreather face mask can significantly boost the effective inspired oxygen. Similarly, with the apnea created by rapid sequence intubation (RSI procedures, the same high-flow nasal cannula can help maintain or increase oxygen saturation during efforts to secure the tube (oral intubation. Thus, the use of nasal oxygen during pre-oxygenation and continued during apnea can prevent hypoxia before and during intubation, extending safe apnea time, and improve first-pass success attempts. We conducted a literature review of nasal-cannula apneic oxygenation during intubation, focusing on two components: oxygen saturation during intubation, and oxygen desaturation time. We performed an electronic literature search from 1980 to November 2017, using PubMed, Elsevier, ScienceDirect, and EBSCO. We identified 14 studies that pointed toward the benefits of using nasal cannula during emergency intubation.

  8. Involvement of dietary saturated fats, from all sources or of dairy origin only, in insulin resistance and type 2 diabetes.

    Science.gov (United States)

    Morio, Béatrice; Fardet, Anthony; Legrand, Philippe; Lecerf, Jean-Michel

    2016-01-01

    Reducing the consumption of saturated fatty acids to a level as low as possible is a European public health recommendation to reduce the risk of cardiovascular disease. The association between dietary intake of saturated fatty acids and development and management of type 2 diabetes mellitus (T2DM), however, is a matter of debate. A literature search was performed to identify prospective studies and clinical trials in humans that explored the association between dietary intake of saturated fatty acids and risk of insulin resistance and T2DM. Furthermore, to assess whether specific foods, and not just the saturated fatty acid content of the food matrix, can have differential effects on human health, the relationship between consumption of full-fat dairy products, a main source of dietary saturated fatty acids, and risk of insulin resistance and T2DM was studied. There is no evidence that dietary saturated fatty acids from varied food sources affect the risk of insulin resistance or T2DM, nor is intake of full-fat dairy products associated with this risk. These findings strongly suggest that future studies on the effects of dietary saturated fatty acids should take into account the complexity of the food matrix. Furthermore, communication on saturated fats and their health effects should be prudent and well informed. © The Author(s) 2015. Published by Oxford University Press on behalf of the International Life Sciences Institute. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  9. Anestesia regional y saturación de oxígeno posoperatorio en el paciente geriátrico

    Directory of Open Access Journals (Sweden)

    Alfonso R León

    2001-06-01

    Full Text Available Numerosos estudios plantean la necesidad de suministrar oxígeno suplementario a pacientes geriátricos en el período posoperatorio (PO, después de anestesia regional como profilaxis de hipoxemia. Teniendo en cuenta lo anterior, se decidió comprobar cómo se comporta la saturación de oxígeno (STO2 en el PO en los pacientes geriátricos que se asistieron con el uso de esta técnica. Previa autorización del consejo científico se seleccionaron al azar 50 pacientes ASA I-II-II (F = 30, K = 20 intervenidos de hemiabdomen inferior y miembros inferiores. Preoperatoriamente se registraron variables demográficas, antecedentes patológicos personales (APP y (STO2. Se realizó anestesia subaracnoidea (SA o peridural (PE. En el PO se realizaron 6 mediciones de la STO2 (cada 10 min durante 1 h a la salida del salón de operaciones. Se procesaron estadísticamente los resultados (comparación de medias. Edad promedio 76 ± 6 años, anestesia PE 20, SA 30, Hb media 10,5 g/L STO2 preoperatorio 94 % ± 1,5. Mediciones en el PO 1ra. 95 % ± 1,8; 2da. 94 % ± 1,3; 3ra. 93 % ± 2,1; 4ta. 95 % ± 1,9; 5ta. 94 % ± 1,5; 6ta. 93 % ± 1,7. No se hallaron diferencias estadísticamente significativas entre estas mediciones, ni en relación con la SOT2 preoperatorias con el uso de esta técnica anestésica en la población geriátricaMany studies state the need to administer supplementary oxygen to elderly patients in the postoperative period (POP after regional anesthesia as a prophylaxis of hipoxemia. Bearing in mind the above mentioned, we decided to confirm the behaviour of oxygen saturation (O2S in the POP of these aged patients that were assisted with this technique. Having cosulted the Scientifc Council, we proceed to a random selection of 50 ASA I-II-III patients (F = 30, K = 20 that underwent an operation of inferior hemiabdomen and lower limbs. Demographic variables, personal pathologic histories (PPH and 02S were obtained before the operation

  10. Electron mobility and saturation of ion yield in 2,2,4,4-tetramethylpentane

    International Nuclear Information System (INIS)

    Poffenberger, P.R.; Astbury, A.; Fincke-Keeler, M.; Keeler, R.K.; Li, Y.; Robertson, L.P.; Rosvick, M.; Schenk, P.; Oram, C.; Sobie, R.

    1993-01-01

    The electron drift mobility μ and zero field free ion yield G fi 0 have been measured for liquid 2,2,4,4-tetramethylpentane using a waveform analysis. The saturation of the ion yield for highly ionizing radiation has also been investigated and parameterized using the Birks' equation. The results obtained are μ=26.3±0.8 cm 2 /V s, G fi 0 =0.743±0.029 electrons/100 eV, and a Birks' factor ranging from kB=0.222±0.014 cm/MeV at 604 V/cm to kB=0.141±0.021 cm/MeV at 3625 V/cm. (orig.)

  11. Oxygen stoichiometry and its influence on superconductivity in Bi2Sr2CaCu2O8+x

    International Nuclear Information System (INIS)

    Krishnaraj, P.; Lelovic, M.; Eror, N.G.; Balachandran, U.

    1994-01-01

    Bi 2 Sr 2 CaCu 2 O 8+x (2212) was synthesized from freeze-dried precursors. The oxygen content of 2212 was determined as a function of temperature and oxygen partial pressure and the variation of Tc with oxygen content was determined. It was found that 2212 without excess oxygen (x = 0) is superconducting. This points to the role of the (Bi-O) ∞ layers as a source for holes in 2212. Four probe resistivity measurements were also performed on 2212. The nature of oxygen intercalation and oxygen removal in 2212 was studied by thermogravimetry and resistivity. It was also found that samples of 2212 with the same oxygen content had different T c 's depending on thermal history. This difference in T c is thought to arise from oxygen occupying different sites in the lattice while maintaining the same total oxygen content

  12. Theoretical study of the interaction of N2 with water molecules. (H2O)/sub n/:N2, n = 1--8

    International Nuclear Information System (INIS)

    Curtiss, L.A.; Eisgruber, C.L.

    1984-01-01

    Ab initio molecular orbital calculations including correlation energy have been carried out on the interaction of a single H 2 O molecule with N 2 . The potential energy surface for H 2 O:N 2 is found to have a minimum corresponding to a HOH xxx N 2 structure with a weak ( -1 ) hydrogen bond. A second, less stable, configuration corresponding to a H 2 O xxx N 2 structure with N 2 bonded side on to the oxygen of H 2 O was found to be either a minimum or a saddle point in the potential energy surface depending on the level of calculation. The minimal STO-3G basis set was used to investigate the interaction of up to eight H 2 O molecules with N 2 . Two types of clusters, one containing only HOH xxx N 2 interactions and the other containing both HOH xxxN 2 and H 2 O xxx N 2 interactions, were investigated for [N 2 :(H 2 O)/sub n/, n = 2--8

  13. CO2 saturated water as two-phase flow for fouling control in reverse electrodialysis.

    Science.gov (United States)

    Moreno, J; de Hart, N; Saakes, M; Nijmeijer, K

    2017-11-15

    When natural feed waters are used in the operation of a reverse electrodialysis (RED) stack, severe fouling on the ion exchange membranes and spacers occurs. Fouling of the RED stack has a strong influence on the gross power density output; which can decrease up to 50%. Moreover, an increase in the pressure loss occurs between the feed water inlet and outlet, increasing the pumping energy and thus decreasing the net power density that can be obtained. In this work, we extensively investigated the use of CO 2 saturated water as two-phase flow cleaning for fouling mitigation in RED using natural feed waters. Experiments were performed in the REDstack research facility located at the Afsluitdijk (the Netherlands) using natural feed waters for a period of 60 days. Two different gas combinations were experimentally investigated, water/air sparging and water/CO 2 (saturated) injection. Air is an inert gas mixture and induces air sparging in the stack. In the case of CO 2 , nucleation, i.e. the spontaneous formation of bubbles, occurs at the spacer filaments due to depressurization of CO 2 saturated water, inducing cleaning. Results showed that stacks equipped with CO 2 saturated water can produce an average net power density of 0.18 W/m 2 under real fouling conditions with minimal pre-treatment and at a low outside temperature of only 8 °C, whereas the stacks equipped with air sparging could only produce an average net power density of 0.04 W/m 2 . Electrochemical impedance spectroscopy measurements showed that the stacks equipped with air sparging increased in stack resistance due to the presence of stagnant bubbles remaining in the stack after every air injection. Furthermore, the introduction of CO 2 gas in the feed water introduces a pH decrease in the system (carbonated solution) adding an additional cleaning effect in the system, thus avoiding the use of environmentally unwanted cleaning chemicals. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All

  14. Tunable photovoltaic effect and solar cell performance of self-doped perovskite SrTiO3

    Directory of Open Access Journals (Sweden)

    K. X. Jin

    2012-12-01

    Full Text Available We report on the tunable photovoltaic effect of self-doped single-crystal SrTiO3 (STO, a prototypical perovskite-structured complex oxide, and evaluate its performance in Schottky junction solar cells. The photovaltaic characteristics of vacuum-reduced STO single crystals are dictated by a thin surface layer with electrons donated by oxygen vacancies. Under UV illumination, a photovoltage of 1.1 V is observed in the as-received STO single crystal, while the sample reduced at 750 °C presents the highest incident photon to carrier conversion efficiency. Furthermore, in the STO/Pt Schottky junction, a power conversion efficiency of 0.88% was achieved under standard AM 1.5 illumination at room temperature. This work establishes STO as a high-mobility photovoltaic semiconductor with potential of integration in self-powered oxide electronics.

  15. Superconductivity induced by oxygen doping in Y{sub 2}O{sub 2}Bi

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Xiyue; Deng, Shuiquan [State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter (FJIRSM), Chinese Academy of Sciences (CAS), Fuzhou (China); Gordon, Elijah E. [Department of Chemistry, North Carolina State University, Raleigh, NC (United States); Whangbo, Myung-Hwan [State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter (FJIRSM), Chinese Academy of Sciences (CAS), Fuzhou (China); Department of Chemistry, North Carolina State University, Raleigh, NC (United States)

    2017-08-14

    When doped with oxygen, the layered Y{sub 2}O{sub 2}Bi phase becomes a superconductor. This finding raises questions about the sites for doped oxygen, the mechanism of superconductivity, and practical guidelines for discovering new superconductors. We probed these questions in terms of first-principles calculations for undoped and O-doped Y{sub 2}O{sub 2}Bi. The preferred sites for doped O atoms are the centers of Bi{sub 4} squares in the Bi square net. Several Bi 6p x/y bands of Y{sub 2}O{sub 2}Bi are raised in energy by oxygen doping because the 2p x/y orbitals of the doped oxygen make antibonding possible with the 6p x/y orbitals of surrounding Bi atoms. Consequently, the condition necessary for the ''flat/steep'' band model for superconductivity is satisfied in O-doped Y{sub 2}O{sub 2}Bi. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

  16. Investigation of photoplethysmographic signals and blood oxygen saturation values on healthy volunteers during cuff-induced hypoperfusion using a multimode PPG/SpO₂ sensor.

    Science.gov (United States)

    Shafique, M; Kyriacou, P A; Pal, S K

    2012-06-01

    Photoplethysmography (PPG) is a technique widely used to monitor volumetric blood changes induced by cardiac pulsations. Pulse oximetry uses the technique of PPG to estimate arterial oxygen saturation values (SpO₂). In poorly perfused tissues, SpO₂ readings may be compromised due to the poor quality of the PPG signals. A multimode finger PPG probe that operates simultaneously in reflectance, transmittance and a combined mode called "transreflectance" was developed, in an effort to improve the quality of the PPG signals in states of hypoperfusion. Experiments on 20 volunteers were conducted to evaluate the performance of the multimode PPG sensor and compare the results with a commercial transmittance pulse oximeter. A brachial blood pressure cuff was used to induce artificial hypoperfusion. Results showed that the amplitude of the transreflectance AC PPG signals were significantly different (p signals obtained from the other two conventional PPG sensors (reflectance and transmittance). At induced brachial pressures between 90 and 135 mmHg, the reflectance finger pulse oximeter failed 25 times (failure rate 42.2 %) to estimate SpO₂ values, whereas the transmittance pulse oximeter failed 8 times (failure rate 15.5 %). The transreflectance pulse oximeter failed only 3 times (failure rate 6.8 %) and the commercial pulse oximeter failed 17 times (failure rate 29.4 %).

  17. The adsorption of NO on an oxygen pre-covered Pt(1 1 1) surface: in situ high-resolution XPS combined with molecular beam studies

    Science.gov (United States)

    Zhu, J. F.; Kinne, M.; Fuhrmann, T.; Tränkenschuh, B.; Denecke, R.; Steinrück, H.-P.

    2003-12-01

    Adsorption of NO on a Pt(1 1 1) surface pre-covered with a p(2 × 2) atomic oxygen layer has been studied in situ by high-resolution X-ray photoelectron spectroscopy and temperature-programmed XPS using third-generation synchrotron radiation at BESSY II, Berlin, combined with molecular beam techniques and ex situ by low energy electron diffraction and temperature-programmed desorption. O 1s XP spectra reveal that an ordered p(2 × 2)-O layer dramatically changes the adsorption behavior of NO as compared to the clean surface. The atomic oxygen occupies fcc hollow sites, and therefore blocks NO adsorption on these sites, which are energetically preferred on clean Pt(1 1 1). As a consequence, NO populates on-top sites at low coverage. At 110 K for higher coverages, NO can additionally adsorb on hcp hollow sites, thereby inducing a shift of the O 1s binding energy of atomic oxygen towards lower energies by about 0.25 eV. The bond strength of the hcp hollow NO species to the substrate is weakened by the presence of atomic oxygen. A sharp p(2 × 2) LEED pattern is observed for NO adsorption on the oxygen pre-covered surface, up to saturation coverage. The total saturation coverage of NO on Pt(1 1 1) pre-covered with varying amounts of oxygen (below 0.25 ML) decreases linearly with the coverage of oxygen. The initial sticking coefficient of NO is reduced from 0.96 on clean Pt(1 1 1) to 0.88 on a p(2 × 2) oxygen pre-covered surface.

  18. Processing of pulse oximeter signals using adaptive filtering and autocorrelation to isolate perfusion and oxygenation components

    Science.gov (United States)

    Ibey, Bennett; Subramanian, Hariharan; Ericson, Nance; Xu, Weijian; Wilson, Mark; Cote, Gerard L.

    2005-03-01

    A blood perfusion and oxygenation sensor has been developed for in situ monitoring of transplanted organs. In processing in situ data, motion artifacts due to increased perfusion can create invalid oxygenation saturation values. In order to remove the unwanted artifacts from the pulsatile signal, adaptive filtering was employed using a third wavelength source centered at 810nm as a reference signal. The 810 nm source resides approximately at the isosbestic point in the hemoglobin absorption curve where the absorbance of light is nearly equal for oxygenated and deoxygenated hemoglobin. Using an autocorrelation based algorithm oxygenation saturation values can be obtained without the need for large sampling data sets allowing for near real-time processing. This technique has been shown to be more reliable than traditional techniques and proven to adequately improve the measurement of oxygenation values in varying perfusion states.

  19. Localized vs. delocalized character of charge carriers in LaAlO3/SrTiO3 heterostructure

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Kejin; Schlappa, Justine; Strocov, Vladimir; Frison, Ruggero; Patthey, Luc; Schmitt, Thorsten [Paul Scherrer Institut, CH-5232 Villigen PSI (Switzerland); Radovic, Milan [Laboratory for Synchrotron and Neutron Spectroscopy, Ecole Polytechnique Federale de Lausanne, CH-1015 Lausanne (Switzerland); Paul Scherrer Institut, CH-5232 Villigen PSI (Switzerland); Mesot, Joel [Paul Scherrer Institut, CH-5232 Villigen PSI (Switzerland); Laboratory for Synchrotron and Neutron Spectroscopy, Ecole Polytechnique Federale de Lausanne, CH-1015 Lausanne (Switzerland)

    2011-07-01

    Oxide heterostructures have been attracting great attention due to extraordinary phenomena occurring at the interface and their potential application for device design. A particularly fascinating system is the two-dimensional conductive interface between the band insulators LaAlO{sub 3} (LAO) and SrTiO{sub 3} (STO), which can be even driven to magnetic and superconducting phases at low temperatures. Resonant inelastic X-ray scattering at Ti L-edges is particularly suitable to address the electronic structure of its interface since the Ti{sup 3+} states clearly display strong dd excitations while Ti{sup 4+} states exhibit only elastic emission in the low energy loss regime. Our studies on LAO/STO superlattices prepared by pulsed laser deposition unambiguously reveal the presence of both localized and delocalized Ti 3d carriers generated during the building of the LAO/STO interfaces. Systematic studies on samples before and after annealing under O{sub 2} atmosphere and high temperature show that the dual character carriers can be either induced by electron transfer due to the polar-discontinuity or by oxygen vacancies defects. Oxygen vacancies and electronic reconstruction are equivalent in balancing the built-up electric potential.

  20. SIMS study of oxygen diffusion in monoclinic HfO2

    Science.gov (United States)

    Mueller, Michael P.; De Souza, Roger A.

    2018-01-01

    The diffusion of oxygen in dense ceramics of monoclinic HfO2 was studied by means of (18O/16O) isotope exchange annealing and subsequent determination of isotope depth profiles by Secondary Ion Mass Spectrometry. Anneals were performed in the temperature range of 573 ≤T /K ≤ 973 at an oxygen partial pressure of p O2=200 mbar . All measured isotope profiles exhibited two features: the first feature, closer to the surface, was attributed mainly to slow oxygen diffusion in an impurity silicate phase; the second feature, deeper in the sample, was attributed to oxygen diffusion in bulk monoclinic HfO2 . The activation enthalpy of oxygen tracer diffusion in bulk HfO2 was found to be ΔHD∗≈0.5 eV .

  1. Atomic oxygen-MoS sub 2 chemical interactions

    Energy Technology Data Exchange (ETDEWEB)

    Cross, J.B.; Martin, J.A. (Los Alamos National Lab., NM (USA)); Pope, L.E. (Sandia National Labs., Albuquerque, NM (USA)); Koontz, S.L. (National Aeronautics and Space Administration, Johnson Space Center, Houston, TX (USA))

    1990-10-01

    The present study shows that an O-atom translation energy of 1.5 eV, SO{sub 2} is generated and outgases from an anhydrous MoS{sub 2} surface with an initial reactivity nearly 50% that of kapton. The reaction of atomic oxygen with MoS{sub 2} has little or no translational energy barrier, i.e. thermally generated atomic oxygen reacts as readily as that having 1.5 eV of translational energy. For MoS{sub 2} films sputter-deposited at 50-70deg C, friction measurements showed a high initial friction coefficient (up to 0.25) for MoS{sub 2} surfaces exposed to atomic oxygen, which dropped to the normal low values after several cycles of operation in air and ultrahigh vacuum. For MoS{sub 2} films deposited at 200deg C, the friction coefficient was not affected by the O-atom exposure. (orig.).

  2. Cell respiration under hypoxia: facts and artefacts in mitochondrial oxygen kinetics.

    Science.gov (United States)

    Scandurra, Francesca M; Gnaiger, Erich

    2010-01-01

    When oxygen supply to tissues is limiting, mitochondrial respiration and ATP production are compromised. To assess the bioenergetic consequences under normoxia and hypoxia, quantitative evaluation of mitochondrial oxygen kinetics is required. Using high-resolution respirometry, the "apparent K (m)" for oxygen or p (50) of respiration in 32D cells was determined at 0.05 +/- 0.01 kPa (0.4 mmHg, 0.5 microM, 0.25% air saturation). Close agreement with p (50) of isolated mitochondria indicates that intracellular gradients are small in small cells at routine activity. At intracellular p (O2) respiration is limited by >2% with a p (50) of 0.05 kPa. Over-estimation of p (50) at 0.4 kPa (3 mmHg) would imply significant (>17%) oxygen limitation of respiration under intracellular normoxia. Based on a critical review, we conclude that p (50) ranges from 0.01 to 0.10 kPa in mitochondria and small cells in the absence of inhibitors of cytochrome c oxidase, whereas experimental artefacts explain the controversial >200-fold range of p (50) in the literature on mitochondrial oxygen kinetics.

  3. New STO(II-3Gmag family basis sets for the calculations of the molecules magnetic properties

    Directory of Open Access Journals (Sweden)

    Karina Kapusta

    2015-10-01

    Full Text Available An efficient approach for construction of physically justified STO(II-3Gmag family basis sets for calculation of molecules magnetic properties has been proposed. The procedure of construction based upon the taken into account the second order of perturbation theory in the magnetic field case. Analytical form of correction functions has been obtained using the closed representation of the Green functions by the solution of nonhomogeneous Schrödinger equation for the model problem of "one-electron atom in the external uniform magnetic field". Their performance has been evaluated for the DFT level calculations carried out with a number of functionals. The test calculations of magnetic susceptibility and 1H nuclear magnetic shielding tensors demonstrated a good agreement of the calculated values with the experimental data.

  4. Singlet oxygen produced by quasi-continuous photo-excitation of hypericin in dimethyl-sulfoxide

    Energy Technology Data Exchange (ETDEWEB)

    Varchola, J.; Želonková, K. [Department of Biophysics, Faculty of Science, P. J. Šafárik University, Jesenná 5, 041 54 Košice (Slovakia); Chorvat Jr, D. [International Laser Centre, Ilkovicova 3, 841 05 Bratislava (Slovakia); Jancura, D. [Department of Biophysics, Faculty of Science, P. J. Šafárik University, Jesenná 5, 041 54 Košice (Slovakia); Center for Interdisciplinary Biosciences, Faculty of Science, P. J. Šafárik University, Jesenná 5, 041 54 Košice (Slovakia); Miskovsky, P. [Department of Biophysics, Faculty of Science, P. J. Šafárik University, Jesenná 5, 041 54 Košice (Slovakia); International Laser Centre, Ilkovicova 3, 841 05 Bratislava (Slovakia); Center for Interdisciplinary Biosciences, Faculty of Science, P. J. Šafárik University, Jesenná 5, 041 54 Košice (Slovakia); and others

    2016-09-15

    Singlet oxygen (O{sub 2}({sup 1}Δ{sub g})) production by photo-excited hypericin (Hyp) dissolved in dimethyl-sulfoxide (DMSO) was studied by means of time-resolved phosphorescence measurements. In order to minimize photo-bleaching, the samples were excited in quasi-continuous mode using long-pulse (35 μs) laser excitation. The measured lifetime of singlet oxygen is τ{sub Δ}=5.5±0.3 μs. This result helps to resolve the discrepancy existing in the literature concerning singlet oxygen lifetime in DMSO. The obtained quantum yield of singlet oxygen photosensitized by Hyp in air-saturated DMSO is Φ{sub Δ}=0.4±0.03. The rate constant for Hyp triplet state depopulation in reaction with ground state molecular oxygen is measured to be k{sub q}=1.6±0.3×10{sup 9} M{sup −1} s{sup −1}.

  5. A Novel β-Globin Chain Hemoglobin Variant, Hb Allentown [β137(H15)Val→Trp (GTG>TGG) HBB: c.412_413delinsTG, p.Val138Trp], Associated with Low Oxygen Saturation, Intermittent Aplastic Crises and Splenomegaly.

    Science.gov (United States)

    Collier, Anderson B; Coon, Lea M; Monteleone, Philip; Umaru, Samuel; Swanson, Kenneth C; Hoyer, James D; Oliveira, Jennifer L

    2016-01-01

    Hemoglobin (Hb) variants may be associated with low oxygen saturation and exacerbated episodes of anemia from common stressors such as viral infections. These attributes frequently cause increased clinical concern and unnecessary and expensive testing if not considered early in the evaluation of the patient. Some clinically significant Hb variants result in a normal Hb electrophoresis result, which can be method-dependent. Herein we describe a patient with low oxygen saturation and a history of hemolytic anemia who was subsequently found to carry a novel, unstable β-globin variant that we have named Hb Allentown [β137(H15)Val→Trp (GTG>TGG) HBB: c.412_413delinsTG, p.Val138Trp] for the place of identification of the variant. Hb Allentown is formed by a rare double nucleotide substitution within the same codon. Additionally, positive identification of rare Hb variants characterized by a single method is discouraged, as the Hb variant was misclassified as Hb S-South End or β6(A3)Glu→Val;β132(H10)Lys→Asn (HBB: c.[20A > T;399A > C]) by the initial laboratory.

  6. Effects of carbogen plus fractionated irradiation on KHT tumor oxygenation

    International Nuclear Information System (INIS)

    Fenton, Bruce M.

    1997-01-01

    Background and purpose: Numerous studies have demonstrated improvements in the oxygenation of tumor cells following both irradiation and carbogen breathing. The current studies were initiated to measure the combined effects of carbogen inhalation plus single and multi-dose irradiation on tumor oxygen availability, to better define the underlying physiological relationships. Materials and methods: Using KHT murine sarcomas, radiation was delivered to the tumor-bearing legs of non-anesthetized mice. Tumors were quick-frozen prior to or following single or multifraction irradiation and carbogen breathing, and intravascular HbO 2 saturation profiles were determined cryospectrophotometrically. Results: HbO 2 levels for blood vessels located near the tumor surface initially decreased following 10 Gy irradiation, then increased and remained elevated. Interior HbO 2 levels remained unchanged. Following 2.5 Gy, HbO 2 changes were minimal. At 24 h following 10 Gy, HbO 2 levels were significantly increased compared to non-irradiated controls, and carbogen breathing produced no additional benefit. At 24 h following five fractions of 2 Gy, HbO 2 levels throughout the tumor volume were significantly higher in carbogen breathing animals than in air breathing controls. Conclusions: Although peripheral blood vessels demonstrated substantial improvements in oxygenation following irradiation, oxygen availability nearer the tumor center remained at very low levels. The utility of carbogen in enhancing tumor oxygen availability was maintained following five clinically relevant fractions. At higher doses, radiation-induced enhancements in HbO 2 levels overshadowed the carbogen effect. For either air or carbogen breathing, a decrease in the percentage of vessels with very low oxygen content did not appear to be a major factor in the reoxygenation of the KHT tumor

  7. Ammonium and nitrite oxidation at nanomolar oxygen concentrations in oxygen minimum zone waters.

    Science.gov (United States)

    Bristow, Laura A; Dalsgaard, Tage; Tiano, Laura; Mills, Daniel B; Bertagnolli, Anthony D; Wright, Jody J; Hallam, Steven J; Ulloa, Osvaldo; Canfield, Donald E; Revsbech, Niels Peter; Thamdrup, Bo

    2016-09-20

    A major percentage of fixed nitrogen (N) loss in the oceans occurs within nitrite-rich oxygen minimum zones (OMZs) via denitrification and anammox. It remains unclear to what extent ammonium and nitrite oxidation co-occur, either supplying or competing for substrates involved in nitrogen loss in the OMZ core. Assessment of the oxygen (O2) sensitivity of these processes down to the O2 concentrations present in the OMZ core (Chile at manipulated O2 levels between 5 nmol⋅L(-1) and 20 μmol⋅L(-1) Rates of both processes were detectable in the low nanomolar range (5-33 nmol⋅L(-1) O2), but demonstrated a strong dependence on O2 concentrations with apparent half-saturation constants (Kms) of 333 ± 130 nmol⋅L(-1) O2 for ammonium oxidation and 778 ± 168 nmol⋅L(-1) O2 for nitrite oxidation assuming one-component Michaelis-Menten kinetics. Nitrite oxidation rates, however, were better described with a two-component Michaelis-Menten model, indicating a high-affinity component with a Km of just a few nanomolar. As the communities of ammonium and nitrite oxidizers were similar to other OMZs, these kinetics should apply across OMZ systems. The high O2 affinities imply that ammonium and nitrite oxidation can occur within the OMZ core whenever O2 is supplied, for example, by episodic intrusions. These processes therefore compete with anammox and denitrification for ammonium and nitrite, thereby exerting an important control over nitrogen loss.

  8. Six-minute walking distance and decrease in oxygen saturation during the six-minute walk test in pediatric pulmonary arterial hypertension

    NARCIS (Netherlands)

    Douwes, Johannes M.; Hegeman, Anneke K.; van der Krieke-van der Horst, Merel; Roofthooft, Marcus T. R.; Hillege, Hans L.; Berger, Rolf M. F.

    2016-01-01

    Objective: To investigate the prognostic value of the 6-minute walking distance (6-MWD), transcutaneous saturation (tcSO2) and heart rate (HR) obtained during the 6-minute walk test (6-MWT) in pediatric pulmonary arterial hypertension (PAH). Methods: This was an observational study with forty-seven

  9. Oxygen-Partial-Pressure Sensor for Aircraft Oxygen Mask

    Science.gov (United States)

    Kelly, Mark; Pettit, Donald

    2003-01-01

    A device that generates an alarm when the partial pressure of oxygen decreases to less than a preset level has been developed to help prevent hypoxia in a pilot or other crewmember of a military or other high-performance aircraft. Loss of oxygen partial pressure can be caused by poor fit of the mask or failure of a hose or other component of an oxygen distribution system. The deleterious physical and mental effects of hypoxia cause the loss of a military aircraft and crew every few years. The device is installed in the crewmember s oxygen mask and is powered via communication wiring already present in all such oxygen masks. The device (see figure) includes an electrochemical sensor, the output potential of which is proportional to the partial pressure of oxygen. The output of the sensor is amplified and fed to the input of a comparator circuit. A reference potential that corresponds to the amplified sensor output at the alarm oxygen-partial-pressure level is fed to the second input of the comparator. When the sensed partial pressure of oxygen falls below the minimum acceptable level, the output of the comparator goes from the low state (a few millivolts) to the high state (near the supply potential, which is typically 6.8 V for microphone power). The switching of the comparator output to the high state triggers a tactile alarm in the form of a vibration in the mask, generated by a small 1.3-Vdc pager motor spinning an eccentric mass at a rate between 8,000 and 10,000 rpm. The sensation of the mask vibrating against the crewmember s nose is very effective at alerting the crewmember, who may already be groggy from hypoxia and is immersed in an environment that is saturated with visual cues and sounds. Indeed, the sensation is one of rudeness, but such rudeness could be what is needed to stimulate the crewmember to take corrective action in a life-threatening situation.

  10. Effect of oxygen vacancy and dopant concentration on the magnetic properties of high spin Co2+ doped TiO2 nanoparticles

    International Nuclear Information System (INIS)

    Choudhury, B.; Choudhury, A.; Maidul Islam, A.K.M.; Alagarsamy, P.; Mukherjee, M.

    2011-01-01

    Co doped TiO 2 nanoparticles have been synthesized by a simple sol-gel route taking 7.5, 9.5 and 10.5 mol% of cobalt concentration. Formation of nanoparticles is confirmed by XRD and TEM. Increase in d-spacing occurs for (0 0 4) and (2 0 0) peak with increase in impurity content. Valence states of Co and its presence in the doped material is confirmed by XPS and EDX. The entire vacuum annealed samples show weak ferromagnetism. Increased magnetization is found for 9.5 mol% but this value again decreases for 10.5 mol% due to antiferromagnetic interactions. A blocking temperature of 37.9 K is obtained, which shows shifting to high temperature as the dopant concentration is increased. The air annealed sample shows only paramagnetic behavior. Temperature dependent magnetic measurements for the air annealed sample shows antiferromagnetic behavior with a Curie-Weiss temperature of -16 K. Here we report that oxygen vacancy and cobalt aggregates are a key factor for inducing ferromagnetism-superparamagnetism in the vacuum annealed sample. Appearance of negative Curie-Weiss temperature reveals the presence of antiferromagnetic Co 3 O 4 , which is the oxidation result of metallic Co or cobalt clusters present on the host TiO 2 . - Research highlights: → Oxygen vacancy induces ferromagnetism in cobalt doped anatase TiO2 nanoparticles. → On air annealing the sample loses ferromagnetism giving rise to paramagnetism. → Saturation magnetization decreases at higher doping concentration. → Blocking of magnetic moment occurs due to the presence of cobalt clusters.

  11. Reactions of oxygen and hydrogen with liquid sodium - a critical survey

    International Nuclear Information System (INIS)

    Ullmann, H.

    1982-01-01

    The fundamentals of solvation chemistry are presented with appropriate components formulated. Methods of investigation and kinetics of the reactions are described. The hydrogen equilibrium pressure and saturation solubilities are described. The chemical equilibrium between O and H in solution is presented with detailed tabulation of the saturation solutions of oxygen, hydrogen and hydroxide in liquid sodium. Agreements and differences with the literature are presented

  12. Comparison the Effects of Shallow and Deep Endotracheal Tube Suctioning on Respiratory Rate, Arterial Blood Oxygen Saturation and Number of Suctioning in Patients Hospitalized in the Intensive Care Unit: A Randomized Controlled Trial

    Directory of Open Access Journals (Sweden)

    Mohammad Abbasinia

    2014-09-01

    Full Text Available Introduction: Endotracheal tube suctioning is essential for improve oxygenation in the patients undergoing mechanical ventilation. There are two types of shallow and deep endotracheal tube suctioning. This study aimed to evaluate the effect of shallow and deep suctioning methods on respiratory rate (RR, arterial blood oxygen saturation (SpO2 and number of suctioning in patients hospitalized in the intensive care units of Al-Zahra Hospital, Isfahan, Iran. Methods: In this randomized controlled trial, 74 patients who hospitalized in the intensive care units of Isfahan Al-Zahra Hospital were randomly allocated to the shallow and deep suctioning groups. RR and SpO2 were measured immediately before, immediately after, 1 and 3 minute after each suctioning. Number of suctioning was also noted in each groups. Data were analyzed using repeated measures analysis of variance (RMANOVA, chi-square and independent t-tests. Results: RR was significantly increased and SpO2 was significantly decreased after each suctioning in the both groups. However, these changes were not significant between the two groups. The numbers of suctioning was significantly higher in the shallow suctioning group than in the deep suctioning group. Conclusion: Shallow and deep suctioning had a similar effect on RR and SpO2. However, shallow suctioning caused further manipulation of patient’s trachea than deep suctioning method. Therefore, it seems that deep endotracheal tube suctioning method can be used to clean the airway with lesser manipulation of the trachea.

  13. Comparison the effects of shallow and deep endotracheal tube suctioning on respiratory rate, arterial blood oxygen saturation and number of suctioning in patients hospitalized in the intensive care unit: a randomized controlled trial.

    Science.gov (United States)

    Abbasinia, Mohammad; Irajpour, Alireza; Babaii, Atye; Shamali, Mehdi; Vahdatnezhad, Jahanbakhsh

    2014-09-01

    Endotracheal tube suctioning is essential for improve oxygenation in the patients undergoing mechanical ventilation. There are two types of shallow and deep endotracheal tube suctioning. This study aimed to evaluate the effect of shallow and deep suctioning methods on respiratory rate (RR), arterial blood oxygen saturation (SpO2) and number of suctioning in patients hospitalized in the intensive care units of Al-Zahra Hospital, Isfahan, Iran. In this randomized controlled trial, 74 patients who hospitalized in the intensive care units of Isfahan Al-Zahra Hospital were randomly allocated to the shallow and deep suctioning groups. RR and SpO2 were measured immediately before, immediately after, 1 and 3 minute after each suctioning. Number of suctioning was also noted in each groups. Data were analyzed using repeated measures analysis of variance (RMANOVA), chi-square and independent t-tests. RR was significantly increased and SpO2 was significantly decreased after each suctioning in the both groups. However, these changes were not significant between the two groups. The numbers of suctioning was significantly higher in the shallow suctioning group than in the deep suctioning group. Conclusion : Shallow and deep suctioning had a similar effect on RR and SpO2. However, shallow suctioning caused further manipulation of patient's trachea than deep suctioning method. Therefore, it seems that deep endotracheal tube suctioning method can be used to clean the airway with lesser manipulation of the trachea.

  14. Probing adsorption phenomena on a single crystal Pt-alloy surface under oxygen reduction reaction conditions

    DEFF Research Database (Denmark)

    Bondarenko, Alexander S.; Stephens, Ifan E.L.; Bech, Lone

    2012-01-01

    The adsorption dynamics of *OH and *O species at Pt(111) and Cu/Pt(111) near-surface alloy (NSA) surfaces in oxygen-free and O2-saturated 0.1M HClO4 was investigated. Subsurface Cu modifies the electronic structure at the Pt(111) surface resulting in weaker bonding to adsorbates like *OH, *H or *O....... This provides a basis for the high oxygen reduction activity of the NSA, as predicted by density functional theory calculations. The shift in *OH adsorption of around 0.16V towards more positive potentials can be clearly monitored in absence of O2 and under the oxygen reduction reaction (ORR) conditions...... for the Cu/Pt(111) NSA. In both cases, for Pt(111) and NSA, the *OH(*O) adsorption dynamics is very similar in the absence of oxygen and under ORR conditions. Therefore, theoretical assumptions about the coverage of adsorbates in the absence of oxygen can be reasonably extrapolated to the situation when...

  15. Measurement of electrical impedance of a Berea sandstone core during the displacement of saturated brine by oil and CO2 injections

    Science.gov (United States)

    Liu, Yu; Xue, Ziqiu; Park, Hyuck; Kiyama, Tamotsu; Zhang, Yi; Nishizawa, Osamu; Chae, Kwang-seok

    2015-12-01

    Complex electrical impedance measurements were performed on a brine-saturated Berea sandstone core while oil and CO2 were injected at different pressures and temperatures. The saturations of brine, oil, and CO2 in the core were simultaneously estimated using an X-ray computed tomography scanner. The formation factor of this Berea core and the resistivity indexes versus the brine saturations were calculated using Archie's law. The experimental results found different flow patterns of oil under different pressures and temperatures. Fingers were observed for the first experiment at 10 MPa and 40 °C. The fingers were restrained as the viscosity ratio of oil and water changed in the second (10 MPa and 25 °C) and third (5 MPa and 25 °C) experiments. The resistivity index showed an exponential increase with a decrease in brine saturation. The saturation exponent varied from 1.4 to 4.0 at different pressure and temperature conditions. During the oil injection procedure, the electrical impedance increased with oil saturation and was significantly affected by different oil distributions; therefore, the impedance varied whether the finger was remarkable or not, even if the oil saturation remained constant. During the CO2 injection steps, the impedance showed almost no change with CO2 saturation because the brine in the pores became immobile after the oil injection.

  16. In-Situ X-ray Tomography Study of Cement Exposed to CO2 Saturated Brine

    DEFF Research Database (Denmark)

    Chavez Panduro, E. A.; Torsæter, M.; Gawel, K.

    2017-01-01

    For successful CO2 storage in underground reservoirs, the potential problem of CO2 leakage needs to be addressed. A profoundly improved understanding of the behavior of fractured cement under realistic subsurface conditions including elevated temperature, high pressure and the presence of CO2...... saturated brine is required. Here, we report in situ X-ray micro computed tomography (μ-CT) studies visualizing the microstructural changes upon exposure of cured Portland cement with an artificially engineered leakage path (cavity) to CO2 saturated brine at high pressure. Carbonation of the bulk cement......, self-healing of the leakage path in the cement specimen, and leaching of CaCO3 were thus directly observed. The precipitation of CaCO3, which is of key importance as a possible healing mechanism of fractured cement, was found to be enhanced in confined regions having limited access to CO2...

  17. Solid-gate control of insulator to 2D metal transition at SrTiO3 surface

    Science.gov (United States)

    Schulman, Alejandro; Stoliar, Pablo; Kitoh, Ai; Rozenberg, Marcelo; Inoue, Isao H.

    As miniaturization of the semiconductor transistor approaches its limit, semiconductor industries are facing a major challenge to extend information processing beyond what can be attainable by conventional Si-based transistors. Innovative combinations of new materials and new processing platforms are desired. Recent discovery of the 2D electron gas (2DEG) at the surface of SrTiO3 (STO) and its electrostatic control, have carried it to the top of promising materials to be utilized in innovative devices. We report an electrostatic control of the carrier density of the 2DEG formed at the channel of bilayer-gated STO field-effect devices. By applying a gate electric field at room temperature, its highly insulating channel exhibits a transition to metallic one. This transition is accompanied by non-monotonic voltage-gain transfer characteristic with both negative and positive slope regions and unexpected enhancement of the sheet carrier density. We will introduce a numerical model to rationalize the observed features in terms of the established physics of field-effect transistors and the physics of percolation. Furthermore, we have found a clear signature of a Kondo effect that arises due to the interaction between the dilute 2DEG and localized Ti 3d orbitals originated by oxygen vacancies near the channel. On leave from CIC nanoGUNE, Spain.

  18. Saturação venosa central e mista de oxigênio no choque séptico: existe diferença clinicamente relevante? Central and mixed venous oxygen saturation in septic shock: is there a clinically relevant difference?

    Directory of Open Access Journals (Sweden)

    Flavia Ribeiro Machado

    2008-12-01

    Full Text Available INTRODUÇÃO: A medida da saturação venosa central de oxigênio (SvcO2 tem sido proposta como alternativa a saturação venosa mista (SvO2, com grau de concordância variável nos dados atualmente disponíveis. Esse estudo objetivou avaliar as possíveis diferenças entre a SvO2 e a SvcO2 ou saturação venosa atrial de oxigênio (SvaO2, com ênfase na interferência do débito cardíaco, e o impacto delas no manejo clínico do paciente séptico. MÉTODOS: Estudo prospectivo observacional em pacientes com choque séptico monitorizados com cateter de artéria pulmonar. Foi obtido sangue simultaneamente para determinação da SvcO2, SvO2 e SvaO2. Realizado testes de correlação linear (significativos se pINTRODUCTION: Central venous oxygen saturation (SvcO2 has been proposed as an alternative for mixed venous oxygen saturation (SvO2, with a variable level of acceptance according to available data. This study aimed to evaluate possible differences between SvO2 and SvcO2 or atrial venous saturation (SvaO2, with emphasis on the role of cardiac output and their impact on clinical management of the septic patient. METHODS: This is an observational, prospective study of patients with septic shock monitored by pulmonary artery catheter. Blood was obtained simultaneously for SvcO2, SvO2 and SvaO2 determination. Linear correlation (significant if p<0.05 and agreement analysis (Bland-Altman were performed with samples and subgroups according to cardiac output. Moreover, agreement about clinical management based on these samples was evaluated. RESULTS: Sixty one measurements from 23 patients were obtained, median age of 65.0 (49.0-75.0 years and mean APACHE II of 27.7±6.3. Mean values of SvO2, SvcO2 and SvaO2 were 72.20±8.26%, 74.61±7.60% and 74.64±8.47%. Linear correlation test showed a weak correlation between SvO2 and SvcO2 (r=0.61, p<0.0001 and also between SvO2 and SvaO2 (r=0.70, p<0.0001. Agreements between SvcO2/SvO2 and SvaO2/SvO2 were -2.40

  19. Fabrication of a saturable absorber WS2 and its mode locking in solid-state laser

    Science.gov (United States)

    Zhang, Chun-Yu; Zhang, Ling; Tang, Xiao-Ying; Yang, Ying-Ying

    2018-04-01

    We report on a passively mode-locked Nd : LuVO4 laser using a type saturable absorber of tungsten disulfide (WS2) fabricated by chemical vapor deposition method. At the pump power of 3.3 W, 1.18-W average output power of continuous-wave mode-locked laser with optical conversion efficiency of 36% was achieved. To the best of our knowledge, this is the highest output power of passively mode-locked solid-state laser based on WS2. The repetition rate of passively mode-locked pulse was 80 MHz with the pulse energy of 14.8 nJ. Our experimental results show that WS2 is an excellent type of saturable absorber.

  20. [Thomas Ditt: „Stoßtruppfakultät Breslau“. Rechtswissenschaft im „Grenzland Schlesien“ 1933-1945. (Beiträge zur Rechtsgeschichte des 20. Jahrhunderts ; 67). Mohr Siebeck. Tübingen 2011] / Marju Luts-Sootak

    Index Scriptorium Estoniae

    Luts-Sootak, Marju, 1966-

    2013-01-01

    Arvustus: Thomas Ditt. „Stoßtruppfakultät Breslau“. Rechtswissenschaft im „Grenzland Schlesien“ 1933-1945. (Beiträge zur Rechtsgeschichte des 20. Jahrhunderts, Bd. 67.) Mohr Siebeck. Tübingen 2011

  1. VS2DRTI: Simulating Heat and Reactive Solute Transport in Variably Saturated Porous Media.

    Science.gov (United States)

    Healy, Richard W; Haile, Sosina S; Parkhurst, David L; Charlton, Scott R

    2018-01-29

    Variably saturated groundwater flow, heat transport, and solute transport are important processes in environmental phenomena, such as the natural evolution of water chemistry of aquifers and streams, the storage of radioactive waste in a geologic repository, the contamination of water resources from acid-rock drainage, and the geologic sequestration of carbon dioxide. Up to now, our ability to simulate these processes simultaneously with fully coupled reactive transport models has been limited to complex and often difficult-to-use models. To address the need for a simple and easy-to-use model, the VS2DRTI software package has been developed for simulating water flow, heat transport, and reactive solute transport through variably saturated porous media. The underlying numerical model, VS2DRT, was created by coupling the flow and transport capabilities of the VS2DT and VS2DH models with the equilibrium and kinetic reaction capabilities of PhreeqcRM. Flow capabilities include two-dimensional, constant-density, variably saturated flow; transport capabilities include both heat and multicomponent solute transport; and the reaction capabilities are a complete implementation of geochemical reactions of PHREEQC. The graphical user interface includes a preprocessor for building simulations and a postprocessor for visual display of simulation results. To demonstrate the simulation of multiple processes, the model is applied to a hypothetical example of injection of heated waste water to an aquifer with temperature-dependent cation exchange. VS2DRTI is freely available public domain software. © 2018, National Ground Water Association.

  2. Measurement of oxygen chemical diffusion in PuO2-x and analysis of oxygen diffusion in PuO2-x and (Pu,U)O2-x

    International Nuclear Information System (INIS)

    Kato, Masato; Uchida, Teppei; Sunaoshi, Takeo

    2013-01-01

    Oxygen chemical diffusion in PuO 2-x was investigated in the temperature range of 1473-1873 K by thermogravimetry as functions of oxygen-to-metal (O/M) ratios and temperatures. The oxygen chemical diffusion coefficients, D were determined assuming that the reduction curves were dominated by a diffusion process. The O/M ratio and Pu content dependence on the chemical diffusion coefficients were evaluated. The chemical diffusion coefficient had its minimum value at around O/M=1.98 and decreased with increasing Pu content in (U,Pu)O 2-x . The self-diffusion coefficients were evaluated. A model for describing the relationship among O/M ratio, oxygen chemical diffusion, and self-diffusion was proposed based on defect chemistry. (copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  3. Oxygen titration strategies in chronic neonatal lung disease.

    Science.gov (United States)

    Primhak, Robert

    2010-09-01

    The history of oxygen therapy in neonatology has been littered with error. Controversies remain in a number of areas of oxygen therapy, including targets and strategies in supplemental oxygen therapy in Chronic Neonatal Lung Disease (CNLD). This article reviews some of these controversies, and makes some recommendations based on the available evidence. In graduates of neonatal units who are left with CNLD, oxygen saturation should be kept above 93-95%, with levels below 90% being avoided as far as possible. Titration of oxygen should be done using oximetry recordings which include periods of different activities. Weaning of oxygen supplementation should only be done based on satisfactory recordings during a trial of a lower flow. There is insufficient evidence to say whether weaning for increasing hours a day or stepwise weaning to a continuous lower flow is a better method. Copyright 2010 Elsevier Ltd. All rights reserved.

  4. Modification of pure oxygen absorption equipment for concurrent stripping of carbon dioxide

    Science.gov (United States)

    Watten, B.J.; Sibrell, P.L.; Montgomery, G.A.; Tsukuda, S.M.

    2004-01-01

    The high solubility of carbon dioxide precludes significant desorption within commercial oxygen absorption equipment. This operating characteristic of the equipment limits its application in recirculating water culture systems despite its ability to significantly increase allowable fish loading rates (kg/(L min)). Carbon dioxide (DC) is typically removed by air stripping. This process requires a significant energy input for forced air movement, air heating in cold climates and water pumping. We developed a modification for a spray tower that provides for carbon dioxide desorption as well as oxygen absorption. Elimination of the air-stripping step reduces pumping costs while allowing dissolved nitrogen to drop below saturation concentrations. This latter response provides for an improvement in oxygen absorption efficiency within the spray tower. DC desorption is achieved by directing head-space gases from the spray tower (O2, N2, CO2) through a sealed packed tower scrubber receiving a 2 N NaOH solution. Carbon dioxide is selectively removed from the gas stream, by chemical reaction, forming the product Na 2CO3. Scrubber off-gas, lean with regard to carbon dioxide but still rich with oxygen, is redirected through the spray tower for further stripping of DC and absorption of oxygen. Make-up NaOH is metered into the scrubbing solution sump on an as needed basis as directed by a feedback control loop programmed to maintain a scrubbing solution pH of 11.4-11.8. The spent NaOH solution is collected, then regenerated for reuse, in a batch process that requires relatively inexpensive hydrated lime (Ca(OH)2). A by-product of the regeneration step is an alkaline filter cake, which may have use in bio-solids stabilization. Given the enhanced gas transfer rates possible with chemical reaction, the required NaOH solution flow rate through the scrubber represents a fraction of the spray tower water flow rate. Further, isolation of the water being treated from the atmosphere (1

  5. Correlation of results obtained by in-vivo optical spectroscopy with measured blood oxygen saturation using a positive linear regression fit

    Science.gov (United States)

    McCormick, Patrick W.; Lewis, Gary D.; Dujovny, Manuel; Ausman, James I.; Stewart, Mick; Widman, Ronald A.

    1992-05-01

    Near infrared light generated by specialized instrumentation was passed through artificially oxygenated human blood during simultaneous sampling by a co-oximeter. Characteristic absorption spectra were analyzed to calculate the ratio of oxygenated to reduced hemoglobin. A positive linear regression fit between diffuse transmission oximetry and measured blood oxygenation over the range 23% to 99% (r2 equals .98, p signal was observed in the patient over time. The procedure was able to be performed clinically without difficulty; rSO2 values recorded continuously demonstrate the usefulness of the technique. Using the same instrumentation, arterial input and cerebral response functions, generated by IV tracer bolus, were deconvoluted to measure mean cerebral transit time. Date collected over time provided a sensitive index of changes in cerebral blood flow as a result of therapeutic maneuvers.

  6. Spontaneous calcium waves in Bergman glia increase with age and hypoxia and may reduce tissue oxygen

    DEFF Research Database (Denmark)

    Mathiesen, Claus; Brazhe, Alexey; Thomsen, Kirsten Joan

    2013-01-01

    Glial calcium (Ca(2+)) waves constitute a means to spread signals between glial cells and to neighboring neurons and blood vessels. These waves occur spontaneously in Bergmann glia (BG) of the mouse cerebellar cortex in vivo. Here, we tested three hypotheses: (1) aging and reduced blood oxygen sa...... activity during aging, as well as low resting brain oxygen tension, suggests a relationship between glial waves, brain energy homeostasis, and pathology.......Glial calcium (Ca(2+)) waves constitute a means to spread signals between glial cells and to neighboring neurons and blood vessels. These waves occur spontaneously in Bergmann glia (BG) of the mouse cerebellar cortex in vivo. Here, we tested three hypotheses: (1) aging and reduced blood oxygen...... saturation alters wave activity; (2) glial Ca(2+) waves change cerebral oxygen metabolism; and (3) neuronal and glial wave activity is correlated. We used two-photon microscopy in the cerebellar cortexes of adult (8- to 15-week-old) and aging (48- to 80-week-old) ketamine-anesthetized mice after bolus...

  7. Investigation on orientation, epitaxial growth and microstructure of a-axis-, c-axis-, (103)/(110)- and (113)-oriented YBa2Cu3O7-δ films prepared on (001), (110) and (111) SrTiO3 single crystal substrates by spray atomizing and coprecipitating laser chemical vapor deposition

    Science.gov (United States)

    Zhao, Pei; Wang, Ying; Huang, Zhi liang; Mao, Yangwu; Xu, Yuan Lai

    2015-04-01

    a-axis-, c-axis-, (103)/(110)- and (113)-oriented YBa2Cu3O7-δ (YBCO) films were pareared by spray atomizing and coprecipitating laser chemical vapor deposition. The surface of the a-axis-oriented YBCO film consisted of rectangular needle-like grains whose in-plane epitaxial growth relationship was YBCO [100] // STO [001] (YBCO [001] // STO [100]), and that of the c-axis-oriented YBCO film consisted of dense flat surface with epitaxial growth relationship of YBCO [001] // STO [001] (YBCO [100] //STO [100]). For the (103)/(110)-oriented and (113)-oriented YBCO film, they showed wedge-shaped and triangle-shaped grains, with corresponding in-plane epitaxial growth relationship of YBCO [110] // STO [110] (YBCO [010] // STO [010]) and YBCO [100] // STO [100] (YBCO [113] // STO [111], respectively.

  8. Initial oxidation behavior of Ni{sub 3}Al (210) surface induced by supersonic oxygen molecular beam at room temperature

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Ya, E-mail: XU.Ya@nims.go.jp [Hydrogen Materials Unit, National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047 (Japan); Sakurai, Junya [Hydrogen Materials Unit, National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047 (Japan); Teraoka, Yuden; Yoshigoe, Akitaka [Quantum Beam Science Center, Japan Atomic Energy Research Agency, 1-1-1 Kouto, Sayo-cho, Hyogo 679-5148 (Japan); Demura, Masahiko; Hirano, Toshiyuki [Hydrogen Materials Unit, National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047 (Japan)

    2017-01-01

    Graphical abstract: - Highlights: • Initial oxidation of Ni{sub 3}Al (210) induced by O{sub 2} beam was investigated. • This was done using real-time synchrotron radiation XPS. • Both the Al and the Ni atoms on the surface were oxidized. • Oxidation of Al progressed much faster than that of Ni. - Abstract: The initial oxidation behavior of a clean Ni{sub 3}Al (210) surface was studied at 300 K using a supersonic O{sub 2} molecular beam (O{sub 2} SSMB) having an O{sub 2} translational energy of 2.3 eV, and real-time photoemission spectroscopy performed with high-brilliance synchrotron radiation. The evolution behaviors of the O 1s, Ni 2p, Al 2p, and Ni 3p spectra were examined during irradiation with the O{sub 2} SSMB. The spectral analysis revealed that both the Al atoms and the Ni atoms on the surface were oxidized; however, the oxidation of Al progressed much faster than that of Ni. The oxidation of Al began to occur and AlO{sub x} was formed at an oxygen coverage of 0.26 monolayer (ML) (1 ML was defined as the atomic density of the Ni{sub 3}Al (210) surface) and saturated at an oxygen coverage of 2.5 ML. In contrast, the oxidation of Ni commenced a little late at an oxygen coverage of 1.6 ML and slowly progressed to saturation, which occurred at an oxygen coverage of 4.89 ML.

  9. Three-Dimensional Near Infrared Imaging of Pathophysiological Changes Within the Breast

    Science.gov (United States)

    2008-03-01

    StO2: Oxygenation Saturatin (in %); H20: Waiter content (in %); a: Scattering Amplitude; b: Scattering Power Typically in these cases of noisy...estimated from Fig. 2(a) for the NN/NM ratio involved. The deviation in run-time that occurs in practice is likely due to the cost of memory management

  10. Oxidation of monovacancies in graphene by oxygen molecules

    KAUST Repository

    Kaloni, Thaneshwor P.; Cheng, Yingchun; Faccio, R.; Schwingenschlö gl, Udo

    2011-01-01

    We study the oxidation of monovacancies in graphene by oxygen molecules using first principles calculations. In particular, we address the local magnetic moments which develop at monovacancies and show that they remain intact when a molecule is adsorbed such that the dangling carbon bonds are not fully saturated. However, the lowest energy configuration does not maintain dangling bonds and is found to be semiconducting. Our data can explain the experimentally observed behavior of graphene under exposure to an oxygen plasma.

  11. Oxidation of monovacancies in graphene by oxygen molecules

    KAUST Repository

    Kaloni, Thaneshwor P.

    2011-10-14

    We study the oxidation of monovacancies in graphene by oxygen molecules using first principles calculations. In particular, we address the local magnetic moments which develop at monovacancies and show that they remain intact when a molecule is adsorbed such that the dangling carbon bonds are not fully saturated. However, the lowest energy configuration does not maintain dangling bonds and is found to be semiconducting. Our data can explain the experimentally observed behavior of graphene under exposure to an oxygen plasma.

  12. Evaluation of Optimum Moisture Content for Composting of Beef Manure and Bedding Material Mixtures Using Oxygen Uptake Measurement

    Directory of Open Access Journals (Sweden)

    Eunjong Kim

    2016-05-01

    Full Text Available Moisture content influences physiological characteristics of microbes and physical structure of solid matrices during composting of animal manure. If moisture content is maintained at a proper level, aerobic microorganisms show more active oxygen consumption during composting due to increased microbial activity. In this study, optimum moisture levels for composting of two bedding materials (sawdust, rice hull and two different mixtures of bedding and beef manure (BS, Beef cattle manure+sawdust; BR, Beef cattle manure+rice hull were determined based on oxygen uptake rate measured by a pressure sensor method. A broad range of oxygen uptake rates (0.3 to 33.3 mg O2/g VS d were monitored as a function of moisture level and composting feedstock type. The maximum oxygen consumption of each material was observed near the saturated condition, which ranged from 75% to 98% of water holding capacity. The optimum moisture content of BS and BR were 70% and 57% on a wet basis, respectively. Although BS’s optimum moisture content was near saturated state, its free air space kept a favorable level (above 30% for aerobic composting due to the sawdust’s coarse particle size and bulking effect.

  13. Evaluation of Optimum Moisture Content for Composting of Beef Manure and Bedding Material Mixtures Using Oxygen Uptake Measurement.

    Science.gov (United States)

    Kim, Eunjong; Lee, Dong-Hyun; Won, Seunggun; Ahn, Heekwon

    2016-05-01

    Moisture content influences physiological characteristics of microbes and physical structure of solid matrices during composting of animal manure. If moisture content is maintained at a proper level, aerobic microorganisms show more active oxygen consumption during composting due to increased microbial activity. In this study, optimum moisture levels for composting of two bedding materials (sawdust, rice hull) and two different mixtures of bedding and beef manure (BS, Beef cattle manure+sawdust; BR, Beef cattle manure+rice hull) were determined based on oxygen uptake rate measured by a pressure sensor method. A broad range of oxygen uptake rates (0.3 to 33.3 mg O2/g VS d) were monitored as a function of moisture level and composting feedstock type. The maximum oxygen consumption of each material was observed near the saturated condition, which ranged from 75% to 98% of water holding capacity. The optimum moisture content of BS and BR were 70% and 57% on a wet basis, respectively. Although BS's optimum moisture content was near saturated state, its free air space kept a favorable level (above 30%) for aerobic composting due to the sawdust's coarse particle size and bulking effect.

  14. Misalignment of disposable pulse oximeter probes results in false saturation readings that influence anesthetic management.

    Science.gov (United States)

    Guan, Zhonghui; Baker, Keith; Sandberg, Warren S

    2009-11-01

    We report a small case series in which misaligned disposable pulse oximeter sensors gave falsely low saturation readings. In each instance, the sensor performed well during preinduction oxygen administration and the early part of the case, most notably by producing a plethysmographic trace rated as high quality by the oximeter software. The reported pulse oximeter oxygen saturation eventually decreased to concerning levels in each instance, but the anesthesiologists, relying on the reported high-quality signal, initially sought other causes for apparent hypoxia. They undertook maneuvers and diagnostic procedures later deemed unnecessary. When the malpositioned sensors were discovered and repositioned, the apparent hypoxia was quickly relieved in each case. We then undertook a survey of disposable oximeter sensors as patients entered the recovery room, and discovered malposition of more than 1 cm in approximately 20% of all sensors, without apparent consequence. We conclude that the technology is quite robust, but that the diagnosis of apparent hypoxia should include a quick check of oximeter position early on.

  15. Carrier density modulation by structural distortions at modified LaAlO3/SrTiO3 interfaces

    International Nuclear Information System (INIS)

    Schoofs, Frank; Vickers, Mary E; Egilmez, Mehmet; Fix, Thomas; Kleibeuker, Josée E; MacManus-Driscoll, Judith L; Blamire, Mark G; Carpenter, Michael A

    2013-01-01

    In order to study the fundamental conduction mechanism of LaAlO 3 /SrTiO 3 (LAO/STO) interfaces, heterostructures were modified with a single unit cell interface layer of either an isovalent titanate ATiO 3 (A = Ca, Sr, Sn, Ba) or a rare earth modified Sr 0.5 RE 0.5 TiO 3 (RE = La, Nd, Sm, Dy) between the LAO and the STO. A strong coupling between the lattice strain induced in the LAO layer by the interfacial layers and the sheet carrier density in the STO substrate is observed. The observed crystal distortion of the LAO is large and it is suggested that it couples into the sub-surface STO, causing oxygen octahedral rotation and deformation. We propose that the ‘structural reconstruction’ which occurs in the STO surface as a result of the stress in the LAO is the enabling trigger for two-dimensional conduction at the LAO/STO interface by locally changing the band structure and releasing trapped carriers. (paper)

  16. Simulation and experiment for oxygen-enriched combustion engine using liquid oxygen to solidify CO2

    Science.gov (United States)

    Liu, Yongfeng; Jia, Xiaoshe; Pei, Pucheng; Lu, Yong; Yi, Li; Shi, Yan

    2016-01-01

    For capturing and recycling of CO2 in the internal combustion engine, Rankle cycle engine can reduce the exhaust pollutants effectively under the condition of ensuring the engine thermal efficiency by using the techniques of spraying water in the cylinder and optimizing the ignition advance angle. However, due to the water spray nozzle need to be installed on the cylinder, which increases the cylinder head design difficulty and makes the combustion conditions become more complicated. In this paper, a new method is presented to carry out the closing inlet and exhaust system for internal combustion engines. The proposed new method uses liquid oxygen to solidify part of cooled CO2 from exhaust system into dry ice and the liquid oxygen turns into gas oxygen which is sent to inlet system. The other part of CO2 is sent to inlet system and mixed with oxygen, which can reduce the oxygen-enriched combustion detonation tendency and make combustion stable. Computing grid of the IP52FMI single-cylinder four-stroke gasoline-engine is established according to the actual shape of the combustion chamber using KIVA-3V program. The effects of exhaust gas recirculation (EGR) rate are analyzed on the temperatures, the pressures and the instantaneous heat release rates when the EGR rate is more than 8%. The possibility of enclosing intake and exhaust system for engine is verified. The carbon dioxide trapping device is designed and the IP52FMI engine is transformed and the CO2 capture experiment is carried out. The experimental results show that when the EGR rate is 36% for the optimum EGR rate. When the liquid oxygen of 35.80-437.40 g is imported into the device and last 1-20 min, respectively, 21.50-701.30 g dry ice is obtained. This research proposes a new design method which can capture CO2 for vehicular internal combustion engine.

  17. Soil aquifer treatment of artificial wastewater under saturated conditions

    KAUST Repository

    Essandoh, H. M K

    2011-05-01

    A 2000 mm long saturated laboratory soil column was used to simulate soil aquifer treatment under saturated conditions to assess the removal of chemical and biochemical oxygen demand (COD and BOD), dissolved organic carbon (DOC), nitrogen and phosphate, using high strength artificial wastewater. The removal rates were determined under a combination of constant hydraulic loading rates (HLR) and variable COD concentrations as well as variable HLR under a constant COD. Within the range of COD concentrations considered (42 mg L-1-135 mg L-1) it was found that at fixed hydraulic loading rate, a decrease in the influent concentrations of dissolved organic carbon (DOC), biochemical oxygen demand (BOD), total nitrogen and phosphate improved their removal efficiencies. At the high COD concentrations applied residence times influenced the redox conditions in the soil column. Long residence times were detrimental to the removal process for COD, BOD and DOC as anoxic processes and sulphate reduction played an important role as electron acceptors. It was found that total COD mass loading within the range of 911 mg d-1-1780 mg d-1 applied as low COD wastewater infiltrated coupled with short residence times would provide better effluent quality than the same mass applied as a COD with higher concentration at long residence times. The opposite was true for organic nitrogen where relatively high concentrations coupled with long residence time gave better removal efficiency. © 2011.

  18. Experimental and modeling investigations of solubility and saturated liquid densities and viscosities for binary systems (methane +, ethane +, and carbon dioxide + 2-propanol)

    International Nuclear Information System (INIS)

    Nourozieh, Hossein; Kariznovi, Mohammad; Abedi, Jalal

    2013-01-01

    Highlights: • Solubilities of CH 4 , C 2 H 6 , and CO 2 in 2-propanol and saturated density and viscosity. • Solubility of C 2 H 6 in 2-propanol is higher than CH 4 and CO 2 . • Dissolution of CO 2 increases liquid density and reduces liquid viscosity. • Liquid density and viscosity reduces with dissolution of CH 4 and C 2 H 6 . • Solubilities and saturated liquid densities were predicted with SRK and PR EOS. -- Abstract: Solubilities of methane, ethane, and carbon dioxide in 2-propanol have been measured at the temperatures (303 and 323) K and at the pressures up to 6 MPa using an in-house designed PVT apparatus. The saturated liquid properties, density and viscosity, were also measured in each experiment. Prior to the phase equilibrium measurements, the density and viscosity of pure 2-propanol were measured at the temperatures (303 and 323) K over the pressure range (0.1 to 10) MPa. The dissolution of carbon dioxide in 2-propanol caused a decline in the viscosity of saturated liquid phase while an increase in the density of gas-expanded liquid was observed. The viscosity-pressure trends for methane- and ethane-saturated liquid viscosities were similar to carbon dioxide, but the saturated liquid densities decreased with the dissolution of methane and ethane in 2-propanol. Solubility increased with pressure and decreased with temperature for all compressed gases (methane, ethane and carbon dioxide). The experimental data were well correlated using Soave–Redlich–Kwong and Peng–Robinson equations of state. The solubilities and saturated liquid densities were well represented with both equations of state, and there is no superior equation of state for the modeling of the phase compositions and saturated liquid densities

  19. Low FEV1, smoking history, and obesity are factors associated with oxygen saturation decrease in an adult population cohort

    Directory of Open Access Journals (Sweden)

    Vold ML

    2014-10-01

    Full Text Available Monica Linea Vold,1,3 Ulf Aasebø,1,2 Hasse Melbye3 1Department of Respiratory Medicine, University Hospital of North Norway, 2Department of Clinical Medicine, 3Department of Community Medicine, University of Tromsø, Tromsø, Norway Background: Worsening of pulmonary diseases is associated with a decrease in oxygen saturation (SpO2. Such a decrease in SpO2 and associated factors has not been previously evaluated in a general adult population. Aim: We sought to describe SpO2 in a sample of adults, at baseline and after 6.3 years, to determine whether factors predicting low SpO2 in a cross-sectional study were also associated with a decrease in SpO2 in this cohort. Methods: As part of the Tromsø Study, 2,822 participants were examined with pulse oximetry in Tromsø 5 (2001/2002 and Tromsø 6 (2007/2008. Low SpO2 by pulse oximetry was defined as an SpO2 ≤95%, and SpO2 decrease was defined as a ≥2% decrease from baseline to below 96%. Results: A total of 139 (4.9% subjects had a decrease in SpO2. Forced expiratory volume in 1 second (FEV1 <50% of the predicted value and current smoking with a history of ≥10 pack-years were the baseline characteristics most strongly associated with an SpO2 decrease in multivariable logistic regression (odds ratio 3.55 [95% confidence interval (CI 1.60–7.89] and 2.48 [95% CI 1.48–4.15], respectively. Male sex, age, former smoking with a history of ≥10 pack-years, body mass index ≥30 kg/m2, and C-reactive protein ≥5 mg/L were also significantly associated with an SpO2 decrease. A significant decrease in FEV1 and a new diagnosis of asthma or chronic obstructive pulmonary disease during the observation period most strongly predicted a fall in SpO2. A lower SpO2 decrease was observed in those who quit smoking and those who lost weight, but these tendencies were not statistically significant. Conclusion: A decrease in SpO2 was most strongly associated with severe airflow limitation and a history of

  20. 31P-NMR measurements of ATP, ADP, 2,3-diphosphoglycerate and Mg2+ in human erythrocytes.

    Science.gov (United States)

    Petersen, A; Kristensen, S R; Jacobsen, J P; Hørder, M

    1990-08-17

    Absolute 31P-NMR measurements of ATP, ADP and 2,3-diphosphoglycerate (2,3-DPG) in oxygenated and partly deoxygenated human erythrocytes, compared to measurements by standard assays after acid extraction, show that ATP is only 65% NMR visible, ADP measured by NMR is unexpectedly 400% higher than the enzymatic measurement and 2,3-DPG is fully NMR visible, regardless of the degree of oxygenation. These results show that binding to hemoglobin is unlikely to cause the decreased visibility of ATP in human erythrocytes as deoxyhemoglobin binds the phosphorylated metabolites more tightly than oxyhemoglobin. The high ADP visibility is unexplained. The levels of free Mg2+ [( Mg2+]free) in human erythrocytes are 225 mumol/l at an oxygen saturation of 98.6% and instead of the expected increase, the level decreased to 196 mumol/l at an oxygen saturation of 38.1% based on the separation between the alpha- and beta-ATP peaks. [Mg2+]free in the erythrocytes decreased to 104 mumol/l at a high 2,3-DPG concentration of 25.4 mmol/l red blood cells (RBC) and a normal ATP concentration of 2.05 mmol/l RBC. By increasing the ATP concentration to 3.57 mmol/l RBC, and with a high 2,3-DPG concentration of 24.7 mmol/l RBC, the 31P-NMR measured [Mg2+]free decreased to 61 mumol/l. These results indicate, that the 31P-NMR determined [Mg2+]free in human erythrocytes, based solely on the separation of the alpha- and beta-ATP peaks, does not give a true measure of intracellular free Mg2+ changes with different oxygen saturation levels. Furthermore the measurement is influenced by the concentration of the Mg2+ binding metabolites ATP and 2,3-DPG. Failure to take these factors into account when interpreting 31P-NMR data from human erythrocytes may explain some discrepancies in the literature regarding [Mg2+]free.

  1. The effects of halide ions on the radiation-induced decoloration of azo and anthraquinone dyes in N2O-saturated aqueous solutions

    International Nuclear Information System (INIS)

    Suzuki, Nobutake; Tokunaga, Okihiro; Washino, Masamitsu

    1978-01-01

    The radiation-induced decoloration of azo and anthraquinone dyes was studied in N 2 O-saturated aqueous solutions containing halide ions. In the N 2 O-saturated solutions, the decoloration yield, G(-Dye), increased markedly upon the addition of Br - and I - , which are efficient scavengers of the OH radical. In the nitrogen-saturated solutions, however, the G(-Dye) decreased upon the addition of Br - and I - . Such an increase in the G(-Dye) upon the addition of Br - and I - in the N 2 O-saturated solutions is mainly attributable to the attacks of the halide radical anions, Br 2 - and I 2 - , on the ring structure of the dyes. On the other hand, the G(-Dye) was not changed upon the addition of Cl - in the N 2 O-saturated solution. This may be attributable to the very slow rate of the formation of Cl 2 - in a neutral solution. (auth.)

  2. Determination of rate constants for the oxygen reduction reaction

    Energy Technology Data Exchange (ETDEWEB)

    Racz, A.; Walter, T.; Stimming, U. [Munich Technical Univ., Garching (Germany). Dept. of Physics

    2008-07-01

    The oxygen reduction reaction (ORR) in fuel cells is a complex and fundamental electrochemical reaction. However, greater insight is needed into this multi-electron reaction in order to develop efficient and innovative catalysts. The rotating ring disc electrode (RRDE) is a useful tool for studying reaction intermediates of the ORR and to better understand the reaction pathway. Carbon materials such as carbon nanofilaments-platelets (CNF-PL) have high electrical conductivity and may be considered for fuel cells. In particular Pt and RuSe{sub x}, deposited on CNF-PL materials could act as efficient catalysts in fuel cells. This study used the RRDE to evaluate the oxygen reduction kinetics of these catalysts in oxygen-saturated, diluted sulphuric acid at room temperature. Kinetic data and hydrogen peroxide formation were determined by depositing a thin-film of the catalyst on the Au disc. The values for the constants k1, k2 and k3 were obtained using diagnostic criteria and expressions to calculate the rate constants of the cathodic oxygen reduction reaction for RuSe on new carbon supports. A potential dependency of the constants k1 and k2 for RuSe{sub x}/CNF-PL was observed. The transition of the Tafel slopes for this catalyst was obtained. 4 refs., 1 fig.

  3. Oxygen sensors for Heavy Liquid Metal coolants: Calibration and assessment of the minimum reading temperature

    Energy Technology Data Exchange (ETDEWEB)

    Bassini, S., E-mail: serena.bassini@enea.it; Antonelli, A.; Di Piazza, I.; Tarantino, M.

    2017-04-01

    Oxygen sensors for Heavy Liquid Metals (HLMs) such as lead and LBE (lead-bismuth eutectic) will be essential devices in future Lead Fast Reactor (LFR) and Accelerator Driven System (ADS). Potentiometric sensors based on solid electrolytes were developed in recent years to this purpose. Internal reference electrodes such as Pt-air and Bi/Bi{sub 2}O{sub 3} liquid metal/metal-oxide are among the most used but they both have a weak point: Pt-air sensor has a high minimum reading temperature around 400 °C whereas Bi/Bi{sub 2}O{sub 3} suffers from internal stresses induced by Bi volume variations with temperature, which may lead to the sensor failure in the long-term. The present work describes the performance of standard Pt-air and Bi/Bi{sub 2}O{sub 3} sensors and compares them with recent Cu/Cu{sub 2}O sensor. Sensors with Yttria Partially Stabilized Zirconia (YPSZ) electrolyte were calibrated in oxygen-saturated HLM between 160 and 550 °C and the electric potential compared to the theoretical one to define the accuracy and the minimum reading temperature. Standard Pt-air sensor were also tested using Yttria Totally Stabilized Zirconia (YTSZ) to assess the effect of a different electrolyte on the minimum reading temperature. The performance of Pt-air and Cu/Cu{sub 2}O sensors with YPSZ electrolyte were then tested together in low-oxygen HLM between 200 and 450 °C. The results showed that Pt-air, Bi/Bi{sub 2}O{sub 3} and Cu/Cu{sub 2}O sensors with YPSZ measured oxygen in HLMs down to 400 °C, 290 °C and 200 °C respectively. When the YTSZ electrolyte was used in place of the YPSZ, the Pt-air sensor measured correctly down to at least 350 °C thanks to the superior ionic conductivity of the YTSZ. When Cu/Cu{sub 2}O and Pt-air sensors were tested together in the same low-oxygen HLM between 200 and 450 °C, Cu/Cu{sub 2}O sensor worked predictably in the whole temperature range whereas Pt-air sensor exhibited a correct output only above 400 °C. - Highlights: •Oxygen

  4. Threshold of carbonate saturation state determined by CO2 control experiment

    Directory of Open Access Journals (Sweden)

    A. Negishi

    2012-04-01

    Full Text Available Acidification of the oceans by increasing anthropogenic CO2 emissions will cause a decrease in biogenic calcification and an increase in carbonate dissolution. Previous studies have suggested that carbonate dissolution will occur in polar regions and in the deep sea where saturation state with respect to carbonate minerals (Ω will be a (aragonite saturation state value of >1. This is probably related to the dissolution of reef carbonate (Mg-calcite, which is more soluble than aragonite. However, the threshold of Ω for the dissolution of natural sediments has not been clearly determined. We designed an experimental dissolution system with conditions mimicking those of a natural coral reef, and measured the dissolution rates of aragonite in corals, and of Mg-calcite excreted by other marine organisms, under conditions of Ωa > 1, with controlled seawater pCO2. The experimental data show that dissolution of bulk carbonate sediments sampled from a coral reef occurs at Ωa values of 3.7 to 3.8. Mg-calcite derived from foraminifera and coralline algae dissolves at Ωa values between 3.0 and 3.2, and coralline aragonite starts to dissolve when Ωa = 1.0. We show that nocturnal carbonate dissolution of coral reefs occurs mainly by the dissolution of foraminiferans and coralline algae in reef sediments.

  5. Adult and newborn rat inner retinal oxygenation during carbogen and 100% oxygen breathing. Comparison using magnetic resonance imaging delta Po2 mapping.

    Science.gov (United States)

    Berkowitz, B A

    1996-09-01

    To test the hypothesis that breathing carbogen (95% O2-5% CO2) oxygenates the inner retina better than breathing 100% oxygen using an magnetic resonance imaging (MRI) method that noninvasively measures inner retinal oxygenation in normal adult and newborn rats. Urethane-anesthetized adult and newborn (day 18) rats were studied. Sequential images were acquired in room air combined with either 100% oxygen or carbogen breathing. Normalized vitreous signal intensity changes were converted to oxygen tension changes (delta PO2) either on a pixel-by-pixel basis or in specific regions of interest. Systemic levels of hyperoxia during carbogen or 100% oxygen breathing were not significantly different (P > 0.05). In the adult rat, a significant difference (P = 0.017) was found in the preretinal vitreous delta PO2 during the breathing of either carbogen (130 +/- 9 mm Hg, mean +/- SEM; n = 5) or 100% oxygen (88 +/- 16 mm Hg; n = 5). Agreement was found between the MRI-determined delta PO2 values and literature oxygen microelectrodes data. In the newborn rat, significant differences (P delta PO2 were found during carbogen (164 +/- 23 mm Hg; n = 3) and oxygen breathing (91 +/- 8 mm Hg; n = 3). MRI delta PO2 mapping demonstrated for the first time that in the normal adult and newborn rat eye, carbogen breathing oxygenates the inner retina better than 100% oxygen breathing.

  6. Thermophysical properties and oxygen transport in (Thx,Pu1-x)O2.

    Science.gov (United States)

    Galvin, C O T; Cooper, M W D; Rushton, M J D; Grimes, R W

    2016-10-31

    Using Molecular Dynamics, this paper investigates the thermophysical properties and oxygen transport of (Th x ,Pu 1-x )O 2 (0 ≤ x ≤ 1) between 300-3500 K. In particular, the superionic transition is investigated and viewed via the thermal dependence of lattice parameter, linear thermal expansion coefficient, enthalpy and specific heat at constant pressure. Oxygen diffusivity and activation enthalpy are also investigated. Below the superionic temperature an increase of oxygen diffusivity for certain compositions of (Th x ,Pu 1-x )O 2 compared to the pure end members is predicted. Oxygen defect formation enthalpies are also examined, as they underpin the superionic transition temperature and the increase in oxygen diffusivity. The increase in oxygen diffusivity for (Th x ,Pu 1-x )O 2 is explained in terms of lower oxygen defect formation enthalpies for (Th x ,Pu 1-x )O 2 than PuO 2 and ThO 2 , while links are drawn between the superionic transition temperature and oxygen Frenkel disorder.

  7. Measuring the microwave response of superconducting Nb:STO and Ti at mK temperatures using superconducting resonators

    Energy Technology Data Exchange (ETDEWEB)

    Thiemann, Markus; Beutel, Manfred; Dressel, Martin; Scheffler, Marc [1. Physikalisches Institut, Universitaet Stuttgart (Germany); Fillis-Tsirakis, Evangelos; Boschker, Hans; Mannhart, Jochen [Max Planck Institute for Solid State Research, Stuttgart (Germany)

    2016-07-01

    Niobium doped SrTiO{sub 3} is a superconductor, with the lowest charge carrier density among all superconductors. It shows a dome in the transition temperature as a function of doping concentration with a maximum T{sub c} ∼ 0.3 K. The superconducting dome may originate from the different bands being occupied depending on the doping level. The low energy scales of the system, as indicated by the low T{sub c} are within the GHz-regime. Therefore microwave measurements are a powerful technique to reveal the electronic properties of these superconductors. We preformed microwave measurements on Nb:STO of different doping levels in a dilution refrigerator, using superconducting stripline resonators. Measurements were done in a temperature and frequency range from 40-400 mK and 1-20 GHz, covering the normal and superconducting states. For comparison we also measured the temperature dependence of the surface impedance of superconducting titanium (T{sub c} ∼ 0.5 K), which can be well described by the Mattis-Bardeen equations with a ratio (2Δ)/(k{sub B}T{sub c}) = 3.56. Therefore titanium is an ideal reference sample representing a conventional BCS-superconductor.

  8. Evidence of ventricular contamination of the optical signal in preterm neonates with post hemorrhagic ventricle dilation

    Science.gov (United States)

    Kishimoto, J.; Diop, M.; McLachlan, P.; de Ribaupierre, S.; Lee, D. S. C.; St. Lawrence, K.

    2015-03-01

    Dilation of the cerebral ventricles is a common condition in preterm neonates with intraventricular hemorrhage (IVH). This post hemorrhagic ventricle dilation (PHVD) can lead to lifelong neurological impairment through ischemic injury due to increased intracranial pressure (ICP). Interventions, such as ventricular tapping to remove cerebrospinal fluid (CSF), are used to prevent injury, but determining the optimal time for treatment is difficult as clinical signs of increased ICP lack sensitivity. There is a growing interest in using near-infrared spectroscopy (NIRS) because of its ability to monitor cerebral oxygen saturation (StO2) at the bedside. However, the accuracy of NIRS may be affected by signal contamination from enlarged ventricles, especially if there are blood breakdown products (bbp) in CSF following IVH. To investigate this, serial NIR spectra from the head and from CSF samples were acquired over a month from seven IVH patients undergoing treatment for PHVD. Over time, the visual appearance of the CSF samples progressed from dark brown ("tea color") to clear yellow, reflecting the reduction in bbp concentration as confirmed by the stronger absorption around 760 nm at the earlier time points. All CSF samples contained strong absorption at 960 nm due to water. More importantly the same trend in these absorption features was observed in the in vivo spectra, and Monte Carlo simulations confirmed the potential for signal contamination from enlarged ventricles. These findings highlight the challenges of accurately measuring StO2 in this patient population and the necessity of using a hyperspectral NIRS system to resolve the additional chromophores.

  9. Growth and properties of oxygen doped Bi2Sr2CaCu2O8+δ single crystals

    International Nuclear Information System (INIS)

    Kapitulnik, A.; Mitzi, D.B.

    1990-01-01

    This paper reports results on oxygen doped single crystals in the Bi 2 Sr 2 CaCu 2 O 8+δ system grown by a directional solidification method. Annealing of as made crystals in increasing partial pressure of oxygen reversibly depresses the superconducting transition temperature from 90K (as made) to 77K (oxygen pressure annealed). Magnetic and photoemission properties of these crystals will be discussed

  10. Comparison of actual oxygen delivery kinetics to those predicted by mathematical modeling following stage 1 palliation just prior to superior cavopulmonary anastomosis.

    Science.gov (United States)

    Yuki, Koichi; DiNardo, James A

    2015-02-01

    Optimizing systemic oxygen delivery (DO2) and hemodynamics in children with hypoplastic left heart syndrome (HLHS) is a clinical challenge. Mathematical modeling of the HLHS circulation has been used to determine the relationship between oxygen kinetic parameters and DO2 and to determine how DO2 might be optimized. The model demonstrates that neither arterial oxygen saturation (SaO2) nor mixed venous oxygen saturation (SvO2) alone accurately predicts DO2. Oxygen delivery kinetics predicted by previously described mathematical modeling were compared with actual patients' hemodynamic data. We sought to determine which patient derived parameters correlated best with DO2. Patients with HLHS who underwent cardiac catheterization prior to surgery to create a superior cavopulmonary anastomosis from 2007 to 2011 were identified. Hemodynamic data obtained were compared with the data derived from the mathematical model. Correlations between SaO2, SvO2, SaO2-SvO2, SaO2/(SaO2-SvO2), pulmonary-to-systemic blood flow ratio (Qp/Qs), and DO2 were evaluated using both linear and nonlinear analyses, and R(2) was calculated. Patients' data fit most aspects of the mathematical model. DO2 had the best correlation with SaO2/(SaO2-SvO2; R(2) = 0.8755) followed by SaO2 -SvO2 (R(2) = 0.8063), while SaO2 or SvO2 alone did not demonstrate a significant correlation as predicated by the mathematical model (R(2) = 0.09564 and 0.4831, respectively). SaO2/(SaO2 -SvO2) would be useful clinically to track changes in DO2 that occur with changes in patient condition or with interventions. © 2014 John Wiley & Sons Ltd.

  11. Eigenspectra optoacoustic tomography achieves quantitative blood oxygenation imaging deep in tissues

    Science.gov (United States)

    Tzoumas, Stratis; Nunes, Antonio; Olefir, Ivan; Stangl, Stefan; Symvoulidis, Panagiotis; Glasl, Sarah; Bayer, Christine; Multhoff, Gabriele; Ntziachristos, Vasilis

    2016-06-01

    Light propagating in tissue attains a spectrum that varies with location due to wavelength-dependent fluence attenuation, an effect that causes spectral corruption. Spectral corruption has limited the quantification accuracy of optical and optoacoustic spectroscopic methods, and impeded the goal of imaging blood oxygen saturation (sO2) deep in tissues; a critical goal for the assessment of oxygenation in physiological processes and disease. Here we describe light fluence in the spectral domain and introduce eigenspectra multispectral optoacoustic tomography (eMSOT) to account for wavelength-dependent light attenuation, and estimate blood sO2 within deep tissue. We validate eMSOT in simulations, phantoms and animal measurements and spatially resolve sO2 in muscle and tumours, validating our measurements with histology data. eMSOT shows substantial sO2 accuracy enhancement over previous optoacoustic methods, potentially serving as a valuable tool for imaging tissue pathophysiology.

  12. Eigenspectra optoacoustic tomography achieves quantitative blood oxygenation imaging deep in tissues.

    Science.gov (United States)

    Tzoumas, Stratis; Nunes, Antonio; Olefir, Ivan; Stangl, Stefan; Symvoulidis, Panagiotis; Glasl, Sarah; Bayer, Christine; Multhoff, Gabriele; Ntziachristos, Vasilis

    2016-06-30

    Light propagating in tissue attains a spectrum that varies with location due to wavelength-dependent fluence attenuation, an effect that causes spectral corruption. Spectral corruption has limited the quantification accuracy of optical and optoacoustic spectroscopic methods, and impeded the goal of imaging blood oxygen saturation (sO2) deep in tissues; a critical goal for the assessment of oxygenation in physiological processes and disease. Here we describe light fluence in the spectral domain and introduce eigenspectra multispectral optoacoustic tomography (eMSOT) to account for wavelength-dependent light attenuation, and estimate blood sO2 within deep tissue. We validate eMSOT in simulations, phantoms and animal measurements and spatially resolve sO2 in muscle and tumours, validating our measurements with histology data. eMSOT shows substantial sO2 accuracy enhancement over previous optoacoustic methods, potentially serving as a valuable tool for imaging tissue pathophysiology.

  13. Oxidative degradation of alternative gasoline oxygenates in aqueous solution by ultrasonic irradiation: Mechanistic study

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Duk Kyung, E-mail: dkim@aum.edu [Department of Physical Science, Auburn University Montgomery, Montgomery, AL 36117 (United States); O' Shea, Kevin E., E-mail: osheak@fiu.edu [Department of Chemistry and Biochemistry, Florida International University, University Park, Miami, FL 33199 (United States); Cooper, William J. [Department of Civil and Environmental Engineering, Urban Water Research Center, University of California Irvine, Irvine, CA 92697-2175 (United States)

    2012-07-15

    Widespread pollution has been associated with gasoline oxygenates of branched ethers methyl tert-butyl ether (MTBE), di-isopropyl ether (DIPE), ethyl tert-butyl ether (ETBE), and tert-amyl ether (TAME) which enter groundwater. The contaminated plume develops rapidly and treatment for the removal/destruction of these ethers is difficult when using conventional methods. Degradation of MTBE, with biological methods and advanced oxidation processes, are rather well known; however, fewer studies have been reported for degradation of alternative oxygenates. Degradation of alternative gasoline oxygenates (DIPE, ETBE, and TAME) by ultrasonic irradiation in aqueous oxygen saturation was investigated to elucidate degradation pathways. Detailed degradation mechanisms are proposed for each gasoline oxygenate. The common major degradation pathways are proposed to involve abstraction of {alpha}-hydrogen atoms by hydroxyl radicals generated during ultrasound cavitation and low temperature pyrolytic degradation of ETBE and TAME. Even some of the products from {beta}-H abstraction overlap with those from high temperature pyrolysis, the effect of {beta}-H abstraction was not shown clearly from product study because of possible 1,5 H-transfer inside cavitating bubbles. Formation of hydrogen peroxide and organic peroxides was also determined during sonolysis. These data provide a better understanding of the degradation pathways of gasoline oxygenates by sonolysis in aqueous solutions. The approach may also serve as a model for others interested in the details of sonolysis. - Highlights: Black-Right-Pointing-Pointer Gasoline oxygenates (ETBE, TAME, DIPE) were completely degraded after 6 hours under ultrasonic irradiation in O{sub 2} saturation. Black-Right-Pointing-Pointer The major degradation pathways were proposed to involve abstraction of {alpha}-hydrogen atoms by hydroxyl radicals and low temperature pyrolytic degradation. Black-Right-Pointing-Pointer The effect of {beta

  14. Even mild respiratory distress alters tissue oxygenation significantly in preterm infants during neonatal transition

    International Nuclear Information System (INIS)

    Schwaberger, Bernhard; Pichler, Gerhard; Binder, Corinna; Pocivalnik, Mirjam; Urlesberger, Berndt; Avian, Alexander

    2014-01-01

    Near-infrared spectroscopy (NIRS) enables continuous non-invasive measurements of regional oxygen saturation (rSO 2 ). The aim was to evaluate the dynamics of rSO 2 of the brain, preductal and postductal tissues during postnatal transition in preterm infants with and without respiratory support (RS). This single-centre study was designed as an exploratory prospective observational study. Fifty one preterm infants (≥ 30 + 0 and < 37 + 0 weeks) delivered by caesarean section were included. RS using a T-Piece-Resuscitator and supplemental oxygen were given according to guidelines. NIRS measurements were carried out by using Invos Monitor (Covidien; USA) for the first 15 min of life. Three NIRS transducers were attached on the forehead (rSO 2 brain), the right forearm (rSO 2 arm) and the left lower leg (rSO 2 leg). Two groups were compared based on need for RS: normal transition (NT) and RS group. Results: In NT group rSO 2 brain increased over time and was significantly higher than rSO 2 arm, whereas in RS group rSO 2 brain and rSO 2 arm increased without significant differences. Courses of rSO 2 arm and rSO 2 leg increased over time and showed a converging pattern with initially lower values of rSO 2 leg in NT group and a diverging pattern with lower levels of rSO 2 leg in RS group. Overall, rSO 2 levels were higher in NT compared to RS group. Conclusion: Our findings indicate that the decreased rSO 2 levels in RS group compared to NT group are not only caused by lower arterial oxygen saturation levels, but also by a compromised perfusion even in infants with only mild respiratory distress. (paper)

  15. Asymmetry of quadriceps muscle oxygenation during elite short-track speed skating.

    Science.gov (United States)

    Hesford, Catherine Mary; Laing, Stewart J; Cardinale, Marco; Cooper, Chris E

    2012-03-01

    It has been suggested that, because of the low sitting position in short-track speed skating, muscle blood flow is restricted, leading to decreases in tissue oxygenation. Therefore, wearable wireless-enabled near-infrared spectroscopy (NIRS) technology was used to monitor changes in quadriceps muscle blood volume and oxygenation during a 500-m race simulation in short-track speed skaters. Six elite skaters, all of Olympic standard (age = 23 ± 1.8 yr, height = 1.8 ± 0.1 m, mass = 80.1 ± 5.7 kg, midthigh skinfold thickness = 7 ± 2 mm), were studied. Subjects completed a 500-m race simulation time trial (TT). Whole-body oxygen consumption was simultaneously measured with muscle oxygenation in right and left vastus lateralis as measured by NIRS. Mean time for race completion was 44.8 ± 0.4 s. VO2 peaked 20 s into the race. In contrast, muscle tissue oxygen saturation (TSI%) decreased and plateaued after 8 s. Linear regression analysis showed that right leg TSI% remained constant throughout the rest of the TT (slope value = 0.01), whereas left leg TSI% increased steadily (slope value = 0.16), leading to a significant asymmetry (P skating has implications for training and performance.

  16. Tm-doped fiber laser mode-locking with MoS2-polyvinyl alcohol saturable absorber

    Science.gov (United States)

    Cao, Liming; Li, Xing; Zhang, Rui; Wu, Duanduan; Dai, Shixun; Peng, Jian; Weng, Jian; Nie, Qiuhua

    2018-03-01

    We have designed an all-fiber passive mode-locking thulium-doped fiber laser that uses molybdenum disulfide (MoS2) as a saturable absorber (SA) material. A free-standing few-layer MoS2-polyvinyl alcohol (PVA) film is fabricated by liquid phase exfoliation (LPE) and is then transferred onto the end face of a fiber connector. The excellent saturable absorption of the fabricated MoS2-based SA allows the laser to output soliton pulses at a pump power of 500 mW. Fundamental frequency mode-locking is realized at a repetition frequency of 13.9 MHz. The central wavelength is 1926 nm, the 3 dB spectral bandwidth is 2.86 nm and the pulse duration is 1.51 ps. Additionally, third-order harmonic mode-locking of the laser is also achieved. The pulse duration is 1.33 ps, which is slightly narrower than the fundamental frequency mode-locking bandwidth. The experimental results demonstrate that the few-layer MoS2-PVA SA is promising for use in 2 μm laser systems.

  17. Using one filter stage of unsaturated/saturated vertical flow filters for nitrogen removal and footprint reduction of constructed wetlands.

    Science.gov (United States)

    Morvannou, Ania; Troesch, Stéphane; Esser, Dirk; Forquet, Nicolas; Petitjean, Alain; Molle, Pascal

    2017-07-01

    French vertical flow constructed wetlands (VFCW) treating raw wastewater have been developed successfully over the last 30 years. Nevertheless, the two-stage VFCWs require a total filtration area of 2-2.5 m 2 /P.E. Therefore, implementing a one-stage system in which treatment performances reach standard requirements is of interest. Biho-Filter ® is one of the solutions developed in France by Epur Nature. Biho-Filter ® is a vertical flow system with an unsaturated layer at the top and a saturated layer at the bottom. The aim of this study was to assess this new configuration and to optimize its design and operating conditions. The hydraulic functioning and pollutant removal efficiency of three different Biho-Filter ® plants commissioned between 2011 and 2012 were studied. Outlet concentrations of the most efficient Biho-Filter ® configuration are 70 mg/L, 15 mg/L, 15 mg/L and 25 mg/L for chemical oxygen demand (COD), 5-day biological oxygen demand (BOD 5 ), total suspended solids (TSS) and total Kjeldahl nitrogen (TKN), respectively. Up to 60% of total nitrogen is removed. Nitrification efficiency is mainly influenced by the height of the unsaturated zone and the recirculation rate. The optimum recirculation rate was found to be 100%. Denitrification in the saturated zone works at best with an influent COD/NO 3 -N ratio at the inflet of this zone larger than 2 and a hydraulic retention time longer than 0.75 days.

  18. Development of Selective Excitation Methods in Nuclear Magnetic Resonance: Investigation of Hemoglobin Oxygenation in Erythrocytes Using Proton and Phosphorus -31 Nuclear Magnetic Resonance

    Science.gov (United States)

    Fetler, Bayard Keith

    1993-01-01

    Nuclear magnetic resonance (NMR) offers a potential method for making measurements of the percent oxygenation of hemoglobin (Hb) in living tissue non-invasively. As a demonstration of the feasibility of such measurements, we measured the percent oxygenation of Hb in red blood cells (erythrocytes) using resonances in the proton-NMR (^1H-NMR) spectrum which are characteristic of oxyhemoglobin (oxy-Hb) and deoxyhemoglobin (deoxy-Hb), and are due to the unique magnetic properties of these molecules. To perform these measurements, we developed a new NMR method of selectively exciting signals in a region of interest with uniform phase and amplitude, while suppressing the signal of the water resonance. With this method, we are able to make exact calculations distinguishing between uniform phase excitation produced at large flip-angles using the non-linear properties of the Bloch equations, and uniform phase excitation produced at small flip-angles using asymmetric pulse excitation functions. We measured the percent oxygenation of three characteristic ^1H-NMR resonances of Hb: two from deoxy-Hb, originating from the N_delta H protons of histidine residue F8, which occur at different frequencies for the alpha and beta chains of Hb; and one from oxy-Hb, originating from the gamma_2 -CH_3 protons of valine residue E11. We performed experiments both on fresh erythrocytes and on erythrocytes depleted of 2,3-diphosphoglycerate (2,3-DPG), and found that oxygen is more tightly bound to Hb in the former case. In both fresh and 2,3-DPG-depleted samples, we found that: (i) from the deoxy-Hb marker resonances, there is a small but significant difference in the oxygen saturation between the alpha and beta chains; (ii) the decrease in the areas of the deoxy-Hb marker resonances correlates well with the increase in the percent oxygenation of Hb as measured optically; (iii) the area of the oxy-Hb marker resonance may be up to ~15% less than the optically measured Hb saturation. We are

  19. Oxygen potential of Th1-yUyO2+x

    International Nuclear Information System (INIS)

    Schram, R.P.C.; Cordfunke, E.H.P.

    1996-03-01

    Oxygen potentials of UO 2 -ThO 2 solid solutions (Th 1-y U y O 2+x ) were retrieved from literature and stored in a database. For each datapoint the oxygen pressure p O 2 the nonstoichiometry x, the temperature T and the uranium concentration y was specified. The data were analyzed using a defect model, which includes electronic disorder, point defects and cluster formation. In addition, the thermochemical representation of Lindemer and Besmann for UO 2+x was extended for the analysis of the Th 1-y U y O 2+x data. The solid solution is regarded as an ideal ternary mixture of UO 2 , ThO 2 and a hypothetical compound U a O b . The thermodynamic properties of this compound U a O b were determined in two oxygen pressure ranges of the database. In both the defect model and thermochemical approach ThO 2 is treated as an inert compound that does not participate in any of the chemical equilibria describing the oxygen potential. (orig.)

  20. Oxygen uptake during the γ-irradiation of fatty acids

    International Nuclear Information System (INIS)

    Metwally, M.M.K.; Moore, J.S.

    1987-01-01

    The radiation-induced oxidation of saturated and unsaturated fatty acids in aqueous solutions has been estimated by measurement of the continuous uptake of oxygen using an oxygen electrode. Chain reactions, initiated by HO radicals, are easily identified to be occurring in the case of unsaturated fatty acids. Other mild oxidation agents, namely (SCN)2 -anion radicals, Br 2 - anion radicals and N 3 -anion radicals, are also found to be capable of oxidizing the polyunsaturated fatty acids. Evidence is presented the O 2- anion radicals may also initiate peroxidation. The oxidation of the polyunsaturated fatty acids is dependent on dose rate, fatty acid concentration, temperature and the presence of antioxidant and other protective agents. Kinetic studies of the reaction of (SCN)2 - anion radicals and Br 2 - anion radicals with linoleic and linolenic acids have been carried out using pulse radiolysis. The bimolecular rate constants for both radical species with the lipids are approx 10 7 mol-? 1 dm 3 s -1 , below their critical micelle concentrations, and decrease at higher concentrations due to micelle formation. (author)