Sample records for pulse oximeter plethysmograph

  1. Delineation of Raw Plethysmograph using Wavelets for Mobile based Pulse Oximeters

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    Soni, Sangeeta


    The non-invasive pulse-oximeter is a crucial parameter in continuous monitoring systems. It plays a vital role from admission of the patient to surgeries with general anaesthesia. The paper proposes the application of wavelet transform to delineate the raw plethysmograph signals obtained from basic portable and mobile-powered electronic hardware. The paper primarily focuses on finding peaks and baseline from noisy infrared and red waveforms which are responsible for calculating heart-rate and oxygen saturation percentages.

  2. Noninvasive assessment of asthma severity using pulse oximeter plethysmograph estimate of pulsus paradoxus physiology

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    Jenkins Cathy A


    Full Text Available Abstract Background Pulsus paradoxus estimated by dynamic change in area under the oximeter plethysmograph waveform (PEP might provide a measure of acute asthma severity. Our primary objective was to determine how well PEP correlates with forced expiratory volume in 1-second (%FEV1 (criterion validity and change of %FEV1 (responsiveness during treatment in pediatric patients with acute asthma exacerbations. Methods We prospectively studied subjects 5 to 17 years of age with asthma exacerbations. PEP, %FEV1, airway resistance and accessory muscle use were recorded at baseline and at 2 and 4 hours after initiation of corticosteroid and bronchodilator treatments. Statistical associations were tested with Pearson or Spearman rank correlations, logistic regression using generalized estimating equations, or Wilcoxon rank sum tests. Results We studied 219 subjects (median age 9 years; male 62%; African-American 56%. Correlation of PEP with %FEV1 demonstrated criterion validity (r = - 0.44, 95% confidence interval [CI], - 0.56 to - 0.30 and responsiveness at 2 hours (r = - 0.31, 95% CI, - 0.50 to - 0.09 and 4 hours (r = - 0.38, 95% CI, - 0.62 to - 0.07. PEP also correlated with airway resistance at baseline (r = 0.28 for ages 5 to 10; r = 0.45 for ages 10 to 17, but not with change over time. PEP was associated with accessory muscle use (OR 1.16, 95% CI, 1.11 to 1.21, P Conclusions PEP demonstrates criterion validity and responsiveness in correlations with %FEV1. PEP correlates with airway resistance at baseline and is associated with accessory muscle use at baseline and at 2 and 4 hours after initiation of treatment. Incorporation of this technology into contemporary pulse oximeters may provide clinicians improved parameters with which to make clinical assessments of asthma severity and response to treatment, particularly in patients who cannot perform spirometry because of young age or severity of illness. It might also allow for earlier recognition


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    Full Text Available Introduction. Pulse oximetry is impaired by hypotention and peripheral vasoconstriction. Digital block may cause to increase tissue perfusion and improve the parameters of pulse oximetry. The purpose of this study was to investigate the effect of digital block on SPa02, lag time and height of plethysmographic wave of pulse oximeter by simulated shock in upper extrimity. Methods. In an experimental study, 34 Paitents under general anesthesia and elective surgery were selected. Lag time and height of pletysmographic wave and SPa02 had been measured in two fingers shocked by cooling, elevation of hand and inflation of cuff; then, compared to opposite middle finger as control. shocked Middle finger were blocked by lidocaine 2% and these parameters were measured in the 15th and 20th minutes after digital block. Data analysis was performed by SPSS using ANOVA. Results. Mean height of plethysmographic wave in blocked finger was signihcontly taller than shocked and control fingers in the 15th minute (respectively, 16.9±6, 10.8 ± 4. 3,10.7 ± 4.3, P < 0.05 and the 20th minute afters digital block (21.1 ± 5.8, 11.8 ± 4.3, 11.2 ± 3.9, P < 0.05. There were not significalt differences between three fingers in lag time and SPa02. Discussion. This study documents effect of digital block, undergoing shock condition in improving the parameters of pulse oximetry.

  4. Pulse Oximeter Plethysmographic Waveform Changes in Awake, Spontaneously Breathing, Hypovolemic Volunteers (United States)


    NOTES 14. ABSTRACT 15. SUBJECT TERMS 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT UU 18. NUMBER OF PAGES 7 19a. NAME OF...Subjects maintained their normal sleep and dietary patterns, refrained from exercise, and abstained from caffeine and other autonomic stimulants such as... stages of LBNP but decreased at 80% and 100% of LBNP tolerance (Fig. 3E). These changes in pulse amplitude and width resulted in a progressive decrease

  5. Estimation of airway obstruction using oximeter plethysmograph waveform data

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    Desmond Renee' A


    Full Text Available Abstract Background Validated measures to assess the severity of airway obstruction in patients with obstructive airway disease are limited. Changes in the pulse oximeter plethysmograph waveform represent fluctuations in arterial flow. Analysis of these fluctuations might be useful clinically if they represent physiologic perturbations resulting from airway obstruction. We tested the hypothesis that the severity of airway obstruction could be estimated using plethysmograph waveform data. Methods Using a closed airway circuit with adjustable inspiratory and expiratory pressure relief valves, airway obstruction was induced in a prospective convenience sample of 31 healthy adult subjects. Maximal change in airway pressure at the mouthpiece was used as a surrogate measure of the degree of obstruction applied. Plethysmograph waveform data and mouthpiece airway pressure were acquired for 60 seconds at increasing levels of inspiratory and expiratory obstruction. At each level of applied obstruction, mean values for maximal change in waveform area under the curve and height as well as maximal change in mouth pressure were calculated for sequential 7.5 second intervals. Correlations of these waveform variables with mouth pressure values were then performed to determine if the magnitude of changes in these variables indicates the severity of airway obstruction. Results There were significant relationships between maximal change in area under the curve (P Conclusion The findings suggest that mathematic interpretation of plethysmograph waveform data may estimate the severity of airway obstruction and be of clinical utility in objective assessment of patients with obstructive airway diseases.

  6. Green Light Pulse Oximeter

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    Scharf, John Edward (Oldsmar, FL)


    A reflectance pulse oximeter that determines oxygen saturation of hemoglobin using two sources of electromagnetic radiation in the green optical region, which provides the maximum reflectance pulsation spectrum. The use of green light allows placement of an oximetry probe at central body sites (e.g., wrist, thigh, abdomen, forehead, scalp, and back). Preferably, the two green light sources alternately emit light at 560 nm and 577 nm, respectively, which gives the biggest difference in hemoglobin extinction coefficients between deoxyhemoglobin, RHb, and oxyhemoglobin, HbO.sub.2.

  7. Where do pulse oximeter probes break? (United States)

    Crede, S; Van der Merwe, G; Hutchinson, J; Woods, D; Karlen, W; Lawn, J


    Pulse oximetry, a non-invasive method for accurate assessment of blood oxygen saturation (SPO2), is an important monitoring tool in health care facilities. However, it is often not available in many low-resource settings, due to expense, overly sophisticated design, a lack of organised procurement systems and inadequate medical device management and maintenance structures. Furthermore medical devices are often fragile and not designed to withstand the conditions of low-resource settings. In order to design a probe, better suited to the needs of health care facilities in low-resource settings this study aimed to document the site and nature of pulse oximeter probe breakages in a range of different probe designs in a low to middle income country. A retrospective review of job cards relating to the assessment and repair of damaged or faulty pulse oximeter probes was conducted at a medical device repair company based in Cape Town, South Africa, specializing in pulse oximeter probe repairs. 1,840 job cards relating to the assessment and repair of pulse oximeter probes were reviewed. 60.2 % of probes sent for assessment were finger-clip probes. For all probes, excluding the neonatal wrap probes, the most common point of failure was the probe wiring (>50 %). The neonatal wrap most commonly failed at the strap (51.5 %). The total cost for quoting on the broken pulse oximeter probes and for the subsequent repair of devices, excluding replacement components, amounted to an estimated ZAR 738,810 (USD $98,508). Improving the probe wiring would increase the life span of pulse oximeter probes. Increasing the life span of probes will make pulse oximetry more affordable and accessible. This is of high priority in low-resource settings where frequent repair or replacement of probes is unaffordable or impossible.

  8. Interference Resilient Sigma Delta-Based Pulse Oximeter. (United States)

    Shokouhian, Mohsen; Morling, Richard; Kale, Izzet


    Ambient light and optical interference can severely affect the performance of pulse oximeters. The deployment of a robust modulation technique to drive the pulse oximeter LEDs can reduce these unwanted effects and increases the resilient of the pulse oximeter against artificial ambient light. The time division modulation technique used in conventional pulse oximeters can not remove the effect of modulated light coming from surrounding environment and this may cause huge measurement error in pulse oximeter readings. This paper presents a novel cross-coupled sigma delta modulator which ensures that measurement accuracy will be more robust in comparison with conventional fixed-frequency oximeter modulation technique especially in the presence of pulsed artificial ambient light. Moreover, this novel modulator gives an extra control over the pulse oximeter power consumption leading to improved power management.

  9. Design of a finger base-type pulse oximeter (United States)

    Lin, Bor-Shyh; Huang, Cheng-Yang; Chen, Chien-Yue; Lin, Jiun-Hung


    A pulse oximeter is a common medical instrument used for noninvasively monitoring arterial oxygen saturation (SpO2). Currently, the fingertip-type pulse oximeter is the prevalent type of pulse oximeter used. However, it is inconvenient for long-term monitoring, such as that under motion. In this study, a wearable and wireless finger base-type pulse oximeter was designed and implemented using the tissue optical simulation technique and the Monte Carlo method. The results revealed that a design involving placing the light source at 135°-165° and placing the detector at 75°-90° or 90°-105° yields the optimal conditions for measuring SpO2. Finally, the wearable and wireless finger base-type pulse oximeter was implemented and compared with the commercial fingertip-type pulse oximeter. The experimental results showed that the proposed optimal finger base-type pulse oximeter design can facilitate precise SpO2 measurement.

  10. Pulse oximeter based mobile biotelemetry application. (United States)

    Işik, Ali Hakan; Güler, Inan


    Quality and features of tele-homecare are improved by information and communication technologies. In this context, a pulse oximeter-based mobile biotelemetry application is developed. With this application, patients can measure own oxygen saturation and heart rate through Bluetooth pulse oximeter at home. Bluetooth virtual serial port protocol is used to send the test results from pulse oximeter to the smart phone. These data are converted into XML type and transmitted to remote web server database via smart phone. In transmission of data, GPRS, WLAN or 3G can be used. The rule based algorithm is used in the decision making process. By default, the threshold value of oxygen saturation is 80; the heart rate threshold values are 40 and 150 respectively. If the patient's heart rate is out of the threshold values or the oxygen saturation is below the threshold value, an emergency SMS is sent to the doctor. By this way, the directing of an ambulance to the patient can be performed by doctor. The doctor for different patients can change these threshold values. The conversion of the result of the evaluated data to SMS XML template is done on the web server. Another important component of the application is web-based monitoring of pulse oximeter data. The web page provides access to of all patient data, so the doctors can follow their patients and send e-mail related to the evaluation of the disease. In addition, patients can follow own data on this page. Eight patients have become part of the procedure. It is believed that developed application will facilitate pulse oximeter-based measurement from anywhere and at anytime.

  11. [Accuracy of a pulse oximeter during hypoxia]. (United States)

    Tachibana, C; Fukada, T; Hasegawa, R; Satoh, K; Furuya, Y; Ohe, Y


    The accuracy of the pulse oximeter was examined in hypoxic patients. We studied 11 cyanotic congenital heart disease patients during surgery, and compared the arterial oxygen saturation determined by both the simultaneous blood gas analysis (CIBA-CORNING 288 BLOOD GAS SYSTEM, SaO2) and by the pulse oximeter (DATEX SATELITE, with finger probe, SpO2). Ninty sets of data on SpO2 and SaO2 were obtained. The bias (SpO2-SaO2) was 1.7 +/- 6.9 (mean +/- SD) %. In cyanotic congenital heart disease patients, SpO2 values were significantly higher than SaO2. Although the reason is unknown, in constantly hypoxic patients, SpO2 values are possibly over-estimated. In particular, pulse oximetry at low levels of saturation (SaO2 below 80%) was not as accurate as at a higher saturation level (SaO2 over 80%). There was a positive correlation between SpO2 and SaO2 (linear regression analysis yields the equation y = 0.68x + 26.0, r = 0.93). In conclusion, the pulse oximeter is useful to monitor oxygen saturation in constantly hypoxic patients, but the values thus obtained should be compared with the values measured directly when hypoxemia is severe.

  12. Pulse oximeter for cyclists in smartphone (United States)

    Martins, L.; Gaidos, O.; dos Santos, I.


    The monitoring of cyclists during physical activity is an important factor to improve their performance. We discuss a new approaches based on smartphone for monitoring physiological signal wirelessly for cyclists, using a pulse oximeter sensor attached to the rider's forehead. This paper presents a wireless pulse Oximeter that was developed with a Nellcor's module, which uses the Standard Host Interface Protocol (SHIP) for communication with the Bluetooth module and sends data for a Smartphone with Android O.S. Then these data are shown in the screen: the heartbeat and saturation percentage. The application was created with App Inventor and the data are sent to Google Maps via Twitter. The results demonstrate the possibility of developing a successful prototype.

  13. Signal-enhancement reflective pulse oximeter with Fresnel lens (United States)

    Chung, Shuang-Chao; Sun, Ching-Cherng


    In this paper, a new reflective pulse oximeter is proposed and demonstrated with implanting a Fresnel lens, which enhances the reflected signal. An optical simulation model incorporated with human skin characteristics is presented to evaluate the capability of the Fresnel lens. In addition, the distance between the light emitting diode and the photodiode is optimized. Compared with the other reflective oximeters, the reflected signal light detected by the photodiode is enhanced to more than 140%.

  14. 78 FR 14097 - Pulse Oximeters-Premarket Notification Submissions [510(k)s]; Guidance for Industry and Food and... (United States)


    ... HUMAN SERVICES Food and Drug Administration Pulse Oximeters--Premarket Notification Submissions... availability of the guidance entitled ``Pulse Oximeters--Premarket Notification Submissions .'' This guidance document pertains to non-invasive pulse oximeters intended for prescription use to measure arterial...

  15. A Prototype of Reflection Pulse Oximeter Designed for Mobile Healthcare. (United States)

    Lu, Zhiyuan; Chen, Xiang; Dong, Zhongfei; Zhao, Zhangyan; Zhang, Xu


    This paper introduces a pulse oximeter prototype designed for mobile healthcare. In this prototype, a reflection pulse oximeter is embedded into the back cover of a smart handheld device to offer the convenient measurement of both heart rate (HR) and SpO2 (estimation of arterial oxygen saturation) for home or mobile applications. Novel and miniaturized circuit modules including a chopper network and a filtering amplifier were designed to overcome the influence of ambient light and interferences that are caused by embedding the sensor into a flat cover. A method based on adaptive trough detection for improved HR and SpO2 estimation is proposed with appropriate simplification for its implementation on mobile devices. A fast and effective photoplethysmogram validation scheme is also proposed. Clinical experiments have been carried out to calibrate and test our oximeter. Our prototype oximeter can achieve comparable performance to a clinical oximeter with no significant difference revealed by paired t -tests ( p = 0.182 for SpO2 measurement and p = 0.496 for HR measurement). The design of this pulse oximeter will facilitate fast and convenient measurement of SpO2 for mobile healthcare.

  16. Development of a Pulse Oximeter Using MSP430 Microcontroller

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    Full Text Available In this paper,we propose and demonstrate the design of a Pulse Oximeter using MSP430FG439 Microcontroller.The Oxygen Saturation and Heart Rate are the two important key parameters for health monitoring of a patients.The proposed system consists of spo₂ Sensor,MSP430FG439 Pulse Oximeter board With LCD Display,PC.The oxygen saturation is calculated by measuring the ratio between the intensities of two different lights.The heart rate is calculated by measuring the elapsed time between the peaks of IR signal.The measured parameters are then transferred to a PC via Zigbee Module and displayed on lcd.

  17. Design of a pulse oximeter for price sensitive emerging markets. (United States)

    Jones, Z; Woods, E; Nielson, D; Mahadevan, S V


    While the global market for medical devices is located primarily in developed countries, price sensitive emerging markets comprise an attractive, underserved segment in which products need a unique set of value propositions to be competitive. A pulse oximeter was designed expressly for emerging markets, and a novel feature set was implemented to reduce the cost of ownership and improve the usability of the device. Innovations included the ability of the device to generate its own electricity, a built in sensor which cuts down on operating costs, and a graphical, symbolic user interface. These features yield an average reduction of over 75% in the device cost of ownership versus comparable pulse oximeters already on the market.

  18. Dapsone Induced Methaemoglobinemia: Early Intraoperative Detection by Pulse Oximeter Desaturation

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    Mahmood Rafiq


    Case signifies the importance of knowledge of any preoperative drug intake and its anaesthetic implications. Also patients on dapsone therapy especially children should be monitored for methaemoglobin levels. Since children with immune thrombocy-topenic purpura are being treated with dapsone these days and many of these patients would be planned for splenectomy, monitoring of preoperative methaemoglobin levels and methaemoglobinemia as a cause of intraoperative pulse oximeter desaturation should be kept in mind.

  19. Novel wearable and wireless ring-type pulse oximeter with multi-detectors. (United States)

    Huang, Cheng-Yang; Chan, Ming-Che; Chen, Chien-Yue; Lin, Bor-Shyh


    The pulse oximeter is a popular instrument to monitor the arterial oxygen saturation (SPO2). Although a fingertip-type pulse oximeter is the mainstream one on the market at present, it is still inconvenient for long-term monitoring, in particular, with respect to motion. Therefore, the development of a wearable pulse oximeter, such as a finger base-type pulse oximeter, can effectively solve the above issue. However, the tissue structure of the finger base is complex, and there is lack of detailed information on the effect of the light source and detector placement on measuring SPO2. In this study, the practicability of a ring-type pulse oximeter with a multi-detector was investigated by optical human tissue simulation. The optimal design of a ring-type pulse oximeter that can provide the best efficiency of measuring SPO2 was discussed. The efficiency of ring-type pulse oximeters with a single detector and a multi-detector was also discussed. Finally, a wearable and wireless ring-type pulse oximeter was also implemented to validate the simulation results and was compared with the commercial fingertip-type pulse oximeter.

  20. Novel Wearable and Wireless Ring-Type Pulse Oximeter with Multi-Detectors

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    Cheng-Yang Huang


    Full Text Available The pulse oximeter is a popular instrument to monitor the arterial oxygen saturation (SPO2. Although a fingertip-type pulse oximeter is the mainstream one on the market at present, it is still inconvenient for long-term monitoring, in particular, with respect to motion. Therefore, the development of a wearable pulse oximeter, such as a finger base-type pulse oximeter, can effectively solve the above issue. However, the tissue structure of the finger base is complex, and there is lack of detailed information on the effect of the light source and detector placement on measuring SPO2. In this study, the practicability of a ring-type pulse oximeter with a multi-detector was investigated by optical human tissue simulation. The optimal design of a ring-type pulse oximeter that can provide the best efficiency of measuring SPO2 was discussed. The efficiency of ring-type pulse oximeters with a single detector and a multi-detector was also discussed. Finally, a wearable and wireless ring-type pulse oximeter was also implemented to validate the simulation results and was compared with the commercial fingertip-type pulse oximeter.

  1. Accuracy of two pulse oximeters at low arterial hemoglobin-oxygen saturation. (United States)

    Carter, B G; Carlin, J B; Tibballs, J; Mead, H; Hochmann, M; Osborne, A


    To evaluate the performance of two pulse oximeters in the measurement of arterial hemoglobin saturation in hypoxemic children. Prospective, repeated-measures observational study. A 16-bed pediatric intensive care unit in a children's tertiary hospital. Sixty-six patients with arterial saturation of Hewlett-Packard pulse oximeter yielding 155 data points (60 with saturations 75% and -0.8% and 8.0% Hewlett-Packard pulse oximeter were -0.5% and 5.1% >75% and 0.4% and 4.6% Hewlett-Packard. Regression coefficients for predicting change in cooximeter value given a change in the Ohmeda pulse oximeter were 0.59 and 0.71 75%, respectively. Similar coefficients for the Hewlett-Packard pulse oximeter were 0.50 and 0.70, respectively. The performance of the Ohmeda pulse oximeter deteriorated below an SpO2 of 75%. The Hewlett-Packard pulse oximeter performed consistently above and below an SpO2 of 75%. The ability of both pulse oximeters to reliably predict change in SaO2 based on change in pulse oximetry was limited. We recommend measurement of PaO2 or SaO2 for important clinical decisions.

  2. Miniaturized pulse oximeter sensor for continuous vital parameter monitoring (United States)

    Fiala, Jens; Reichelt, Stephan; Werber, Armin; Bingger, Philipp; Zappe, Hans; Förster, Katharina; Klemm, Rolf; Heilmann, Claudia; Beyersdorf, Friedhelm


    A miniaturized photoplethysmographic sensor system which utilizes the principle of pulse oximetry is presented. The sensor is designed to be implantable and will permit continuous monitoring of important human vital parameters such as arterial blood oxygen saturation as well as pulse rate and shape over a long-term period in vivo. The system employs light emitting diodes and a photo transistor embedded in a transparent elastic cu. which is directly wrapped around an arterial vessel. This paper highlights the specific challenges in design, instrumentation, and electronics associated with that sensor location. In vitro measurements were performed using an artificial circulation system which allows for regulation of the oxygen saturation and pulsatile pumping of whole blood through a section of a domestic pig's arterial vessel. We discuss our experimental results compared to reference CO-oximeter measurements and determine the empirical calibration curve. These results demonstrate the capabilities of the pulse oximeter implant for measurement of a wide range of oxygen saturation levels and pave the way for a continuous and mobile monitoring of high-risk cardiovascular patients.

  3. Accuracy of pulse oximeters in detecting hypoxemia in patients with chronic thromboembolic pulmonary hypertension.

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    Tomoki Kohyama

    Full Text Available Pulse oximetry is routinely used to continuously and non-invasively monitor arterial oxygen saturation (SaO2. When oxygen saturation by pulse oximeter (SpO2 overestimates SaO2, hypoxemia may be overlooked. We compared the SpO2 - SaO2 differences among three pulse oximeters in patients with chronic thromboembolic pulmonary hypertension (CTEPH who spent their daily lives in a poor oxygen state.This prospective observational study recruited 32 patients with CTEPH undergoing elective cardiac catheterization. As we collected arterial blood samples in the catheter laboratory, SpO2 values were simultaneously recorded. Three pulse oximeters were used on each patient, and SpO2 values were compared with oximetry readings using a blood gas analyzer. To determine the optimal SpO2 value by which to detect hypoxemia (SaO2≦90%, we generated receiver operating characteristic (ROC curves for each pulse oximeter.The root mean square of each pulse oximeter was 1.79 (OLV-3100, 1.64 (N-BS, and 2.50 (Masimo Radical. The mean bias (SpO2 - SaO2 for the 90%-95% saturation range was significantly higher for Masimo Radical (0.19 +/- 1.78% [OLV-3100], 0.18 +/- 1.63% [N-BS], and 1.61 +/- 1.91% [Masimo Radical]; p<0.0001. The optimal SpO2 value to detect hypoxemia (SaO2≦90% was 89% for OLV-3100, 90% for N-BS, and 92% for Masimo Radical.We found that the biases and precision with which to detect hypoxemia differed among the three pulse oximeters. To avoid hypoxemia, the optimal SpO2 should be determined for each pulse oximeter.

  4. Clinical use of new-generation pulse oximeters in the neonatal intensive care unit. (United States)

    Workie, Fegegta A; Rais-Bahrami, K; Short, Billie L


    Continuous monitoring by pulse oximetry is a common practice for preterm and critically ill newborns. A new generation of motion-tolerant pulse oximeters have been designed for improved clinical performance with a substantial reduction in alarm frequency. However, little is known about the differences among these new-generation pulse oximeters in the neonatal intensive care unit (NICU). The purpose of this study is to assess the clinical performance of two new-generation pulse oximeters in the NICU. Two new-generation pulse oximeters were used simultaneously to monitor 36 patients in the NICU. The two devices studied were the Philips FAST and the Masimo SET. Patients were randomly assigned for their digit selection and data were collected only when waveforms were of good quality and/or the pulse oximeter's pulse rate (PR) correlated with the electrocardiogram heart rate (HR). The data for oxygen saturation measurements, number of true and false alarms, and number of dropouts as well as the duration of dropouts for each pulse oximeter were recorded by the primary investigator at 5-minute intervals for a period of 2 hours on each patient. Dropouts are instances when the pulse oximeter alarm sounds due to its inability to identify the arterial pulse and provide an oxygen saturation reading. The mean gestational age for the study group was 32 weeks (rang, 24 to 42 weeks). Repeated-measures analysis of variance indicated no difference between the two devices across all time measurements (p=0.357). In addition, paired t-tests for true alarms and false alarms were not significant, with p-values of 0.151 and 0.869, respectively. There was a difference in the number of data dropouts (pMasimo 38). The duration of dropouts was also significant; the Philips device had three times longer duration of dropouts. Physiologic monitoring in the critical care setting requires accurate data measurements. The two new-generation pulse oximeters, the Philips FAST and Masimo SET, are

  5. A comparison of the failure times of pulse oximeters during blood pressure cuff-induced hypoperfusion in volunteers. (United States)

    Kawagishi, Toshiya; Kanaya, Noriaki; Nakayama, Masayasu; Kurosawa, Saori; Namiki, Akiyoshi


    Important information may not be obtained if the pulse oximetry signal is lost during inflation of a cuff for blood pressure measurement, particularly in patients with hemodynamic instability. In the present study, we compared the failure times of pulse oximeters during cuff-induced hypoperfusion in volunteers. A pulse oximeter sensor was attached to the index finger, and a blood pressure cuff was attached to the same arm of each volunteer. MasimoSET Radical (Masimo), Nellcor N-395 (N-395), Nellcor N-20PA, and Nellcor D-25 were tested. To evaluate the failure time of each pulse oximeter, time to peak of cuff pressure, time to loss of signal, time to recovery of signal, and failure interval were measured. All measurements were performed three times for each pulse oximeter and were averaged. There were no differences in hemodynamic measurements among the groups. Time to loss of signal was longer in Masimo than the other pulse oximeters. Masimo and N-395 showed significantly shorter times to recovery of signal than those of the other two pulse oximeters. Failure interval was in the order of Masimo Masimo did not lose a signal as rapidly as the other oximeters studied. Masimo was similar in performance to the N-395 at providing useful data sooner than conventional technology after a loss of the signal. These observations suggest that data will be more available with fewer false-positive alarms when using the Masimo oximeter followed by the N-395 when compared with conventional oximeters.

  6. Accuracy of the Lifebox pulse oximeter during hypoxia in healthy volunteers. (United States)

    Dubowitz, G; Breyer, K; Lipnick, M; Sall, J W; Feiner, J; Ikeda, K; MacLeod, D B; Bickler, P E


    Pulse oximetry is a standard of care during anaesthesia in high-income countries. However, 70% of operating environments in low- and middle-income countries have no pulse oximeter. The 'Lifebox' oximetry project set out to bridge this gap with an inexpensive oximeter meeting CE (European Conformity) and ISO (International Organization for Standardization) standards. To date, there are no performance-specific accuracy data on this instrument. The aim of this study was to establish whether the Lifebox pulse oximeter provides clinically reliable haemoglobin oxygen saturation (Sp O2 ) readings meeting USA Food and Drug Administration 510(k) standards. Using healthy volunteers, inspired oxygen fraction was adjusted to produce arterial haemoglobin oxygen saturation (Sa O2 ) readings between 71% and 100% measured with a multi-wavelength oximeter. Lifebox accuracy was expressed using bias (Sp O2 - Sa O2 ), precision (SD of the bias) and the root mean square error (Arms). Simultaneous readings of Sa O2 and Sp O2 in 57 subjects showed a mean (SD) bias of -0.41% (2.28%) and Arms 2.31%. The Lifebox pulse oximeter meets current USA Food and Drug Administration standards for accuracy, thus representing an inexpensive solution for patient monitoring without compromising standards.

  7. [Evaluation of circulatory state using pulse oximeter: 2. PI (perfusion index) x PVI (pleth variability index)]. (United States)

    Kaneda, Toru; Suzuki, Toshiyasu


    Pulse oximeter expressed by SpO2 is used for monitoring respiratory state during operation and in ICU. Perfusion index (PI) and pleth variability index (PVI) as new indexes are calculated from pulse oximeter (Masimo SET Radical-7, Masimo Corp., USA, 1998) waveforms. And these indices were used as parameters to evaluate the circulatory state. For PI calculation, the pulsatile infrared signal is indexed against the nonpulsatile infrared signal and expressed as a percentage. It might thus be of future value in assessment of perioperative changes in peripheral perfusion. PVI is a measure of a dynamic change in PI that occurs during complete respiratory cycle. It might be thought that PVI, an index automatically derived from the pulse oximeter waveform analysis, had potentially clinical applications for noninvasive hypovolemia detection and fluid responsiveness monitoring.

  8. Rejection of false saturation data in optical pulse-oximeter (United States)

    Scalise, Lorenzo; Marchionni, Paolo; Carnielli, Virgilio


    Pulse oximetry (PO) is a non-invasive medical device used for monitoring of the arterial oxygen saturation (SaO2) and in particular of haemoglobin oxygenation in blood. Oxygen saturation is commonly used in any setting where the patient blood oxygen saturation is unstable, including Neonatal Intensive Care Unit (NICU). The main factor affecting PO's output data is the presence of voluntary or involuntary motion artifacts or imperfect skin-sensor contact. Various methods have been employed to reject motion artifact but have met with little success. The aim of the present work is to propose a novel measurement procedure for real-time monitoring and validation of the oxygen saturation data as measured in standard pulse oxymeter. The procedure should be able to individuate and reject erroneous saturation data due to incorrect transducer-skin contact or motion artifact. In the case of short sequences of rejected SpO2 data (time durationoximeter (HRSAT) and the SpO2 value. In order to remove the erroneous SpO2 values reported in the rough data in coincidence of motion artifact (top, right), we have implemented a specific algorithm which provides at the output a new sequence of SpO2 data (validated SpO2 data). With the aim to "rescue" SpO2 value rejected by the previously presented algorithm, we have implemented an algorithm able to provide the "most-probable" SpO2 values in the case of single rejected values or in the case of short sequences of invalidated data (oximeter are not validated by the use of our method (corresponding to a total time of 16 hr, 8min and 40s). The use of the proposed algorithm aiming to "rescue" data from short sequences of rejected data (< 8s) allows to increase the validated data of the 2.5%t(equivalent to 8hr, 40 min and 16s), allowing a percent of usable data of the 95.7%. Once implemented in clinic, it could be used to identify the period of the day in which the percent of rejected data increase or correlate this data to clinical procedure

  9. Pulse oximeter improvement with an ADC-DAC feedback loop and a radial reflectance sensor. (United States)

    Thompson, David; Wareing, Austin; Day, Dwight; Warren, Steve


    Pulse oximeter circuitry must meet several design constraints, including the ability to separate a small pulsatile signal component from a large signal baseline. This paper describes pulse oximeter design changes that produced order-of-magnitude improvements in signal quality. The primary changes were (a) the replacement of an analog sample-and-hold-based differentiator circuit with an ADC-DAC feedback loop and (b) the replacement of a side-by-side reflectance sensor design with a radial sensor arrangement that maximizes the pulsatile-to-baseline signal ratio.

  10. Variability in time delay between two models of pulse oximeters for deriving the photoplethysmographic signals. (United States)

    Foo, Jong Yong A; Wilson, Stephen J; Dakin, Carolyn; Williams, Gordon; Harris, Margaret-Anne; Cooper, David


    Pulse oximetry is commonly used as an arterial blood oxygen saturation (SaO2) measure. However, its other serial output, the photoplethysmography (PPG) signal, is not as well studied. Raw PPG signals can be used to estimate cardiovascular measures like pulse transit time (PTT) and possibly heart rate (HR). These timing-related measurements are heavily dependent on the minimal variability in phase delay of the PPG signals. Masimo SET Rad-9 and Novametrix Oxypleth oximeters were investigated for their PPG phase characteristics on nine healthy adults. To facilitate comparison, PPG signals were acquired from fingers on the same hand in a random fashion. Results showed that mean PTT variations acquired from the Masimo oximeter (37.89 ms) were much greater than the Novametrix (5.66 ms). Documented evidence suggests that 1 ms variation in PTT is equivalent to 1 mmHg change in blood pressure. Moreover, the PTT trend derived from the Masimo oximeter can be mistaken as obstructive sleep apnoeas based on the known criteria. HR comparison was evaluated against estimates attained from an electrocardiogram (ECG). Novametrix differed from ECG by 0.71+/-0.58% (pMasimo differed by 4.51+/-3.66% (p>0.05). Modern oximeters can be attractive for their improved SaO2 measurement. However, using raw PPG signals obtained directly from these oximeters for timing-related measurements warrants further investigations.

  11. Simulink based behavioural modelling of a pulse oximeter for deployment in rapid development, prototyping and verification. (United States)

    Shokouhian, M; Morling, R C S; Kale, I


    The pulse oximeter is a well-known device for measuring the level of oxygen in blood. Since their invention, pulse oximeters have been under constant development in both aspects of hardware and software; however there are still unsolved problems that limit their performance [6], [7]. Many fresh algorithms and new design techniques are being suggested every year by industry and academic researchers which claim that they can improve accuracy of measurements [8], [9]. With the lack of an accurate computer-based behavioural model for pulse oximeters, the only way for evaluation of these newly developed systems and algorithms is through hardware implementation which can be both expensive and time consuming. This paper presents an accurate Simulink based behavioural model for a pulse oximeter that can be used by industry and academia alike working in this area, as an exploration as well as productivity enhancement tool during their research and development process. The aim of this paper is to introduce a new computer-based behavioural model which provides a simulation environment from which new ideas can be rapidly evaluated long before the real implementation.

  12. Comparison of the Nellcor N-200 and N-3000 pulse oximeters during simulated postoperative activities

    DEFF Research Database (Denmark)

    Lie, C; Kehlet, H; Rosenberg, J


    Twenty-six healthy volunteers were monitored simultaneously with the Nellcor N-200 and N-3000 pulse oximeters during nonhypoxaemic simulated postoperative activity. The overall number of registered events (hypoxaemic episodes or loss of signal) was fewer with the N-3000 than with the N-200 (8 vs...... to loss of signal were significantly rarer with the N-3000 than with the N-200 (3 vs. 13, p = 0.001). The Nellcor N-3000 oximeter may offer an advantage over the N-200 model when monitoring patients in the postoperative period....

  13. An ultra-low-power pulse oximeter implemented with an energy-efficient transimpedance amplifier. (United States)

    Tavakoli, M; Turicchia, L; Sarpeshkar, R


    Pulse oximeters are ubiquitous in modern medicine to noninvasively measure the percentage of oxygenated hemoglobin in a patient's blood by comparing the transmission characteristics of red and infrared light-emitting diode light through the patient's finger with a photoreceptor. We present an analog single-chip pulse oximeter with 4.8-mW total power dissipation, which is an order of magnitude below our measurements on commercial implementations. The majority of this power reduction is due to the use of a novel logarithmic transimpedance amplifier with inherent contrast sensitivity, distributed amplification, unilateralization, and automatic loop gain control. The transimpedance amplifier, together with a photodiode current source, form a high-performance photoreceptor with characteristics similar to those found in nature, which allows LED power to be reduced. Therefore, our oximeter is well suited for portable medical applications, such as continuous home-care monitoring for elderly or chronic patients, emergency patient transport, remote soldier monitoring, and wireless medical sensing. Furthermore, our design obviates the need for an A-to-D and digital signal processor and leads to a small single-chip solution. We outline how extensions of our work could lead to submilliwatt oximeters.

  14. Use of a prototype pulse oximeter for time series analysis of heart rate variability (United States)

    González, Erika; López, Jehú; Hautefeuille, Mathieu; Velázquez, Víctor; Del Moral, Jésica


    This work presents the development of a low cost pulse oximeter prototype consisting of pulsed red and infrared commercial LEDs and a broad spectral photodetector used to register time series of heart rate and oxygen saturation of blood. This platform, besides providing these values, like any other pulse oximeter, processes the signals to compute a power spectrum analysis of the patient heart rate variability in real time and, additionally, the device allows access to all raw and analyzed data if databases construction is required or another kind of further analysis is desired. Since the prototype is capable of acquiring data for long periods of time, it is suitable for collecting data in real life activities, enabling the development of future wearable applications.

  15. [Evaluation of circulatory state using pulse oximeter: 2. Measurement of total hemoglobin employing pulse CO-oximetry (Masimo Radical-7)]. (United States)

    Miyoshi, Hiroshi; Sumikawa, Koji


    Development of pulse oximeter technology has made it possible to measure total hemoglobin noninvasively. The use of Radical-7 would improve patient care in emergency medicine and chronic internal medicine as well as perioperative medicine, and could reduce the burden of the patient.

  16. Performance Evaluation of New-Generation Pulse Oximeters in the NICU: Observational Study. (United States)

    Nizami, Shermeen; Greenwood, Kim; Barrowman, Nick; Harrold, JoAnn


    This crossover observational study compares the data characteristics and performance of new-generation Nellcor OXIMAX and Masimo SET SmartPod pulse oximeter technologies. The study was conducted independent of either original equipment manufacturer (OEM) across eleven preterm infants in a Neonatal Intensive Care Unit (NICU). The SmartPods were integrated with Dräger Infinity Delta monitors. The Delta monitor measured the heart rate (HR) using an independent electrocardiogram sensor, and the two SmartPods collected arterial oxygen saturation (SpO2) and pulse rate (PR). All patient data were non-Gaussian. Nellcor PR showed a higher correlation with the HR as compared to Masimo PR. The statistically significant difference found in their median values (1% for SpO2, 1 bpm for PR) was deemed clinically insignificant. SpO2 alarms generated by both SmartPods were observed and categorized for performance evaluation. Results for sensitivity, positive predictive value, accuracy and false alarm rates were Nellcor (80.3, 50, 44.5, 50%) and Masimo (72.2, 48.2, 40.6, 51.8%) respectively. These metrics were not statistically significantly different between the two pulse oximeters. Despite claims by OEMs, both pulse oximeters exhibited high false alarm rates, with no statistically or clinically significant difference in performance. These findings have a direct impact on alarm fatigue in the NICU. Performance evaluation studies can also impact medical device purchase decisions made by hospital administrators.

  17. Design and Construction of a Microcontroller-Based Ventilator Synchronized with Pulse Oximeter. (United States)

    Gölcük, Adem; Işık, Hakan; Güler, İnan


    This study aims to introduce a novel device with which mechanical ventilator and pulse oximeter work in synchronization. Serial communication technique was used to enable communication between the pulse oximeter and the ventilator. The SpO2 value and the pulse rate read on the pulse oximeter were transmitted to the mechanical ventilator through transmitter (Tx) and receiver (Rx) lines. The fuzzy-logic-based software developed for the mechanical ventilator interprets these values and calculates the percentage of oxygen (FiO2) and Positive End-Expiratory Pressure (PEEP) to be delivered to the patient. The fuzzy-logic-based software was developed to check the changing medical states of patients and to produce new results (FiO2 ve PEEP) according to each new state. FiO2 and PEEP values delivered from the ventilator to the patient can be calculated in this way without requiring any arterial blood gas analysis. Our experiments and the feedbacks from physicians show that this device makes it possible to obtain more successful results when compared to the current practices.

  18. Investigation of signal processing algorithms for an embedded microcontroller-based wearable pulse oximeter. (United States)

    Johnston, W S; Mendelson, Y


    Despite steady progress in the miniaturization of pulse oximeters over the years, significant challenges remain since advanced signal processing must be implemented efficiently in real-time by a relatively small size wearable device. The goal of this study was to investigate several potential digital signal processing algorithms for computing arterial oxygen saturation (SpO(2)) and heart rate (HR) in a battery-operated wearable reflectance pulse oximeter that is being developed in our laboratory for use by medics and first responders in the field. We found that a differential measurement approach, combined with a low-pass filter (LPF), yielded the most suitable signal processing technique for estimating SpO(2), while a signal derivative approach produced the most accurate HR measurements.

  19. Preliminary clinical investigations of a new noninvasive venous pulse oximeter (United States)

    Chan, Daniel; Smith, Peter R.; Caine, Michael P.; Spyt, Tomasz; Boehm, Maria; Machin, David


    For decades, the monitoring of mixed venous oxygen saturation, SvO2 has been performed invasively using fibre-optic catheters. This procedure is not without risk as complications may arise from catheterisation. The group has devised a new non-invasive venous oximetry method which involves inducing regular modulations of the venous blood volume and associated measurement of those modulations using optical means. A clinical investigation was conducted in Glenfield Hospital, UK to evaluate the sensitivity of the new technique to haemodynamic changes such as Cardiac Output (CO) in intraoperative and postoperative cardiac patients. Preliminary trials on patients recovering from cardiac surgery yielded an average correlation of r = 0.72 between CO at different Intra Aortic Balloon Pump (IABP) augmentation levels and SvO2 measured by the new venous oximeter. In intraoperative patients undergoing off-pump cardiac surgery, SvO2 recorded by the new technique responded to unplanned events such as a cardiac arrest. CONCLUSION: The new venous oximetry technique is a promising technique which responds to haemodynamic changes such as CO and with further development might offer an alternative means of monitoring SvO2 non-invasively.

  20. Effect of lingual gauze swab placement on pulse oximeter readings in anaesthetised dogs and cats. (United States)

    Mair, A; Martinez-Taboada, F; Nitzan, M


    This study aimed to evaluate the effect of lingual gauze swab placement on pulse oximeter readings in anaesthetised dogs and cats. Following anaesthetic induction, the following pulse oximeter probe configurations were performed: no gauze swab (control), placement of a gauze swab between the tongue and the probe, placement of different thicknesses of gauze swab, placement of red cotton fabric, placement of a sheet of white paper and placement of the probe and gauze swab on different locations on the tongue. Oxygen saturation (SpO2) and peripheral perfusion index (PI) were recorded. Placement of a gauze swab between the pulse oximeter probe and the tongue in anaesthetised dogs and cats resulted in significantly higher SpO2 values compared with the control group. In dogs, PI values were significantly higher than the control in all groups except the quarter thickness swab group. In cats, PI was significantly higher in the double thickness swab and white paper groups compared with the control. Cats had significantly higher SpO2 and lower PI values than dogs. The authors propose that increased contact pressure is responsible for significantly higher SpO2 and PI readings with the use of a lingual gauze swab resulting from changes in transmural pressure and arterial compliance. British Veterinary Association.

  1. Design and Evaluation of a Low-Cost Smartphone Pulse Oximeter

    Directory of Open Access Journals (Sweden)

    Christian L. Petersen


    Full Text Available Infectious diseases such as pneumonia take the lives of millions of children in low- and middle-income countries every year. Many of these deaths could be prevented with the availability of robust and low-cost diagnostic tools using integrated sensor technology. Pulse oximetry in particular, offers a unique non-invasive and specific test for an increase in the severity of many infectious diseases such as pneumonia. If pulse oximetry could be delivered on widely available mobile phones, it could become a compelling solution to global health challenges. Many lives could be saved if this technology was disseminated effectively in the affected regions of the world to rescue patients from the fatal consequences of these infectious diseases. We describe the implementation of such an oximeter that interfaces a conventional clinical oximeter finger sensor with a smartphone through the headset jack audio interface, and present a simulator-based systematic verification system to be used for automated validation of the sensor interface on different smartphones and media players. An excellent agreement was found between the simulator and the audio oximeter for both oxygen saturation and heart rate over a wide range of optical transmission levels on 4th and 5th generations of the iPod TouchTM and iPhoneTM devices.

  2. [Noninvasive fetal pulse oximetry sub partu. Experiences with the Ohmeda Biox 3700 and the Baxter Asat 1000 Pulse Oximeter]. (United States)

    Golaszewski, T; Frigo, P; Ulm, M; Lee, A; Gruber, W; Rafolt, D; Heger, G; Golaszewski, S


    In this study oxygen saturation was measured at the presenting part of the fetus during labour. We used two different reflectance sensors together with two different pulse oximeters. The Baxter Asat 100 displayed a 25% lower functional oxygen saturation of haemoglobin (SaO2) compared to the Ohmeda Biox 3700 pulse oximeter. The mean duration of application using the Ohmeda Biox 3700 together with an adapted finger sensor was 36 min (SD +/- 17 min), an effective measurement was achieved for 15 min (SD +/- 9 min). The mean duration of application using the Baxter Asat 100 together with a commercial Baxter reflex sensor was 88 min (SD +/- 96 min), an effective measurement was attained for 73 min (SD +/- 77 min).

  3. Concurrent validity of resting pulse-rate measurements: a comparison of 2 smartphone applications, the polar H7 belt monitor, and a pulse oximeter with bluetooth. (United States)

    Cheatham, Scott W; Kolber, Morey J; Ernst, Michael P


    Pulse rate is commonly measured manually or with commercial wrist or belt monitors. More recently, pulse-rate monitoring has become convenient with the use of mobile technology that allows monitoring through a smartphone camera. This optical technology offers many benefits, although the clinimetric properties have not been extensively studied. Observational study of reliability Setting: University kinesiology laboratory. 30 healthy, recreationally active adults. Concurrent measurement of pulse rate using 2 smartphone applications (fingertip, face-scan,) with the Polar H7 belt and pulse oximeter. Average resting pulse rate for 5 min in 3 positions (supine, sitting, and prone). Concurrent validity in supine and standing was good between the 2 applications and the Polar H7 (intraclass correlation coefficient [ICC] .80-.98) and pulse oximeter (ICC .82-.98). For sitting, the validity was good between the fingertip application, Polar H7 (ICC .97), and pulse oximeter (ICC .97). The face-scan application had moderate validity with the Polar H7 (ICC .74) and pulse oximeter (ICC .69). The minimal detectable change (MDC90) between the fingertip application and Polar H7 ranged from 1.38 to 4.36 beats/min (BPM) and from 0.69 to 2.97 BPM for the pulse oximeter with both positions. The MDC90 between the face-scan application and Polar H7 ranged from 11.88 to 12.83 BPM and from 0.59 to 17.72 BPM for the pulse oximeter. The 95% limits of agreement suggest that the fingertip application may vary between 2.40 and 3.59 BPM with the Polar H7 and between 3.40 and 3.42 BPM with the pulse oximeter. The face-scan application may vary between 3.46 and 3.52 BPM with the Polar H7 and between 2.54 and 3.46 BPM with the pulse oximeter. Pulse-rate measurements may be effective using a fingertip application, belt monitor, and pulse oximeter. The fingertip scanner showed superior results compared with the face scanner, which only demonstrated modest validity compared with the Polar H7 and pulse

  4. Combined pulse-oximeter-NIRS system for biotissue diagnostics (United States)

    Hovhannisyan, Vladimir A.


    Multi-wavelength (670, 805, 848 and 905 nm), multi-detector device for non-invasive measurement of biochemical components concentration in human or animal tissues, combining the methods of conventional pulse-oximetry and near infrared spectroscopy, is developed. The portable and clinically applicable system allows to measure heart pulse rate, oxygen saturation of arterial hemoglobin (pulse-oximetry method) and local absolute concentration of oxyhemoglobin, deoxyhemoglobin and oxidized cytochrome aa3 or other IR absorbed compounds (NIRS method). The system can be applied in monitoring of oxygen availability and utilization by the brain in neonatal and adults, neuro- traumatology, intensive care medicine, transplantation and plastic surgery, in sport, high-altitude and aviation medicine.

  5. A finger-free wrist-worn pulse oximeter for the monitoring of chronic obstructive pulmonary disease (United States)

    Chu, Chang-Sheng; Chuang, Shuang-Chao; Lee, Yeh Wen; Fan, Chih-Hsun; Chung, Lung Pin; Li, Yu-Tang; Chen, Jyh-Chern


    Herein, a finger-free wrist-worn pulse oximeter is presented. This device allows patients to measure blood oxygen level and pulse rate without hindering their normal finger movement. This wrist-worn pulse oximeter is built with a reflectance oximetry sensor, which consists of light emitting diodes and photodiode light detectors located side by side. This reflectance oximetry sensor is covered with an optical element with micro structured surface. This micro structured optical element is designed to modulate photon propagation beneath the skin tissue so that the photoplethysmogram signals of reflected lights or backscattered lights detected by the photodetector are therefore enhanced.

  6. Experimental and clinical evaluation of a noninvasive reflectance pulse oximeter sensor. (United States)

    Takatani, S; Davies, C; Sakakibara, N; Zurick, A; Kraenzler, E; Golding, L R; Noon, G P; Nose, Y; DeBakey, M E


    The objective of this study was to evaluate a new reflectance pulse oximeter sensor. The prototype sensor consists of 8 light-emitting diode (LED) chips (4 at 665 nm and 4 at 820 nm) and a photodiode chip mounted on a single substrate. The 4 LED chips for each wavelength are spaced at 90-degree intervals around the substrate and at an equal radial distance from the photodiode chip. An optical barrier between the photodiode and LED chips prevents a direct coupling effect between them. Near-infrared LEDs (940 nm) in the sensor warm the tissue. The microthermocouple mounted on the sensor surface measures the temperature of the skin-sensor interface and maintains it at a present level by servoregulating the current in the 940-nm LEDs. An animal study and a clinical study were performed. In the animal study, 5 mongrel dogs (weight, 10-20 kg) were anesthetized, mechanically ventilated, and cannulated. In each animal, arterial oxygen saturation (SaO2) was measured continuously by a standard transmission oximeter probe placed on the dog's earlobe and a reflectance oximeter sensor placed on the dog's tongue. In the first phase of the experiment, signals from the reflectance sensor were recorded while the dog was immersed in ice water until its body temperature decreased to 30 degrees C. In the second phase, the animal's body temperature was normal, and the oxygen content of the ventilator was varied to alter the SaO2. In the clinical study, 18 critically ill patients were monitored perioperatively with the prototype reflectance sensor. The first phase of the study investigated the relationship between local skin temperature and the accuracy of oximeter readings with the reflectance sensor. Each measurement was taken at a high saturation level as a function of local skin temperature. The second phase of the study compared measurements of oxygen saturation by a reflectance oximeter (SpO2[r]) with those made by a co-oximeter (SaO2[IL]) and a standard transmission oximeter (Sp

  7. A conversion formula for comparing pulse oximeter desaturation rates obtained with different averaging times.

    Directory of Open Access Journals (Sweden)

    Jan Vagedes

    Full Text Available OBJECTIVE: The number of desaturations determined in recordings of pulse oximeter saturation (SpO2 primarily depends on the time over which values are averaged. As the averaging time in pulse oximeters is not standardized, it varies considerably between centers. To make SpO2 data comparable, it is thus desirable to have a formula that allows conversion between desaturation rates obtained using different averaging times for various desaturation levels and minimal durations. METHODS: Oxygen saturation was measured for 170 hours in 12 preterm infants with a mean number of 65 desaturations <90% per hour of arbitrary duration by using a pulse oximeter in a 2-4 s averaging mode. Using 7 different averaging times between 3 and 16 seconds, the raw red-to-infrared data were reprocessed to determine the number of desaturations (D. The whole procedure was carried out for 7 different minimal desaturation durations (≥ 1, ≥ 5, ≥ 10, ≥ 15, ≥ 20, ≥ 25, ≥ 30 s below SpO2 threshold values of 80%, 85% or 90% to finally reach a conversion formula. The formula was validated by splitting the infants into two groups of six children each and using one group each as a training set and the other one as a test set. RESULTS: Based on the linear relationship found between the logarithm of the desaturation rate and the logarithm of the averaging time, the conversion formula is: D2 = D1 (T2/T1(c, where D2 is the desaturation rate for the desired averaging time T2, and D1 is the desaturation rate for the original averaging time T1, with the exponent c depending on the desaturation threshold and the minimal desaturation duration. The median error when applying this formula was 2.6%. CONCLUSION: This formula enables the conversion of desaturation rates between different averaging times for various desaturation thresholds and minimal desaturation durations.

  8. The effect of subareolar isosulfan blue injection on pulse oximeter readings. (United States)

    Zengel, Baha; Yararbas, Ulkem; Bingolballi, Ozge; Denecli, Ali Galip


    Besides several side effects including anaphylaxis, blue dyes are also known to cause false pulse oximeter readings. We aimed to examine the effects of subareolar isosulfan blue injection on pulse oximeter (SpO2) readings. The study group included 27 patients undergoing SLNB using both radiocolloid and isosulfan blue. Another group of 27 patients constituted the control group. Pulse oximeter readings were compared. SpO2 decline ≥4 % was defined as significant. All but one (96.2 %) of the patients in the study group showed SpO2 declines, compared to only one patient in the control group. Median ± Interqartile Range (IR) SpO2 decrease was 3.0 ± 4.0 % in the study and 0.0 ± 1.0 % in the control group (p < 0.001). There were significant (≥4 %) SpO2 decreases in 13 (48.1 %) patients in the study group. Statistically significant differences were noted between the two groups in all recordings between 15 and 180 min (p < 0.001). Initial time for SpO2 fall and the time to the lowest SpO2 recording were 10.0 ± 10.0 and 40.0 ± 30.0 min respectively. Using subareolar injection, the frequency of false readings is comparable with intraparenchymal injections, and is higher than intradermal injections. Time to peak SpO2 fall, and the recovery period, are delayed in the subareolar technique.

  9. Masimo Rad-57 Pulse CO-Oximeter for noninvasive carboxyhemoglobin measurement. (United States)

    Suner, Selim; McMurdy, John


    Noninvasive methods of body fluid chemical measurement have been expanding. New technologies are enabling the quantification of different compounds in the blood and interstitial tissues. One example of this is the pulse oximeter, which has facilitated the measurement of oxyhemoglobin rapidly and reliably without the requirement of blood-draws. The Masimo Rad-57 Pulse CO-Oximeter expanded the capabilities of pulse-oximetry to include measurements of carboxyhemoglobin and methemoglobin. This innovation has revolutionized the paradigm for detection of patients with CO poisoning. Previously, clinicians relied on historical information and patient signs and symptoms pointing to the possibility of CO exposure or toxicity. Only then would a blood test be ordered to measure carboxyhemoglobin levels. Since the presentation of CO poisoning is nonspecific and overlaps with many other conditions, and since the presence of environmental CO is often unknown, the detection of this condition was only possible in cases where the presence of CO was obvious or where the symptoms were severe. We now know, from studies conducted using the Rad-57, the only US FDA-approved device for noninvasive measurement of SpCO, that there are a significant number of patients who experience CO exposure but are nonsymptomatic. The Rad-57 provides a clinical justification for screening in the healthcare setting to identify patients with significant CO exposure who would otherwise be undetected.

  10. False alarm rates of three third-generation pulse oximeters in PACU, ICU and IABP patients. (United States)

    Lutter, Norbert O; Urankar, Sabine; Kroeber, Steffi


    The objective of this clinical study was to determine alarm rates--in particular the frequency of false positive alarms--of three third-generation pulse oximeters in the postanesthesia care unit (PACU), the intensive care unit (ICU), and in patients with an intra-aortic balloon pump (IABP): Nellcor Symphony N-3000, a Masimo IVY 2000, and Agilent Viridia CMS 2000. All alarms were classified into technical/physiological and false/correct. 235 consecutive ASA physical status I-IV patients after surgery were included into the study. In the PACU false positive alarms were rare: CMS n = 60, N-3000 n = 60, Masimo n = 87. Bland-Altman testing discovered only negligible differences of alarm rates and dropout times. Out of a total of 728 alarms 67.3% were classified as false positive in ICU-patients: 97 alarms by CMS, 176 by N-3000 and 218 by Masimo SET. If IABP was present, CMS indicated a significant smaller number of false positive alarms (n = 35, 7.2%) when compared to Masimo SET (n = 188, 38.9%) and N-3000 (n = 229, 47.4%), consecutively the majority of false positive alarms (76.2%) can be rated as a result of the interference of IABP. Unless IABP (and to a considerably smaller extent cardiac arrhythmia) is present the pulse oximeters do not differ significantly regarding sensitivity and specificity.

  11. Cardiac gating with a pulse oximeter for dual-energy imaging

    Energy Technology Data Exchange (ETDEWEB)

    Shkumat, N A; Siewerdsen, J H [Department of Medical Biophysics, University of Toronto, Toronto, Ontario, M5G 2M9 (Canada); Dhanantwari, A C; Williams, D B [Ontario Cancer Institute, Princess Margaret Hospital, 610 University Ave., Toronto, Ontario, M5G 2M9 (Canada); Paul, N S [Department of Medical Imaging, University Health Network, Toronto, Ontario, M5G 2M9 (Canada); Yorkston, J; Van Metter, R [Carestream Health Inc., Rochester, NY 14650 (United States)], E-mail:


    The development and evaluation of a prototype cardiac gating system for double-shot dual-energy (DE) imaging is described. By acquiring both low- and high-kVp images during the resting phase of the cardiac cycle (diastole), heart misalignment between images can be reduced, thereby decreasing the magnitude of cardiac motion artifacts. For this initial implementation, a fingertip pulse oximeter was employed to measure the peripheral pulse waveform ('plethysmogram'), offering potential logistic, cost and workflow advantages compared to an electrocardiogram. A gating method was developed that accommodates temporal delays due to physiological pulse propagation, oximeter waveform processing and the imaging system (software, filter-wheel, anti-scatter Bucky-grid and flat-panel detector). Modeling the diastolic period allowed the calculation of an implemented delay, t{sub imp}, required to trigger correctly during diastole at any patient heart rate (HR). The model suggests a triggering scheme characterized by two HR regimes, separated by a threshold, HR{sub thresh}. For rates at or below HR{sub thresh}, sufficient time exists to expose on the same heartbeat as the plethysmogram pulse [t{sub imp}(HR) = 0]. Above HR{sub thresh}, a characteristic t{sub imp}(HR) delays exposure to the subsequent heartbeat, accounting for all fixed and variable system delays. Performance was evaluated in terms of accuracy and precision of diastole-trigger coincidence and quantitative evaluation of artifact severity in gated and ungated DE images. Initial implementation indicated 85% accuracy in diastole-trigger coincidence. Through the identification of an improved HR estimation method (modified temporal smoothing of the oximeter waveform), trigger accuracy of 100% could be achieved with improved precision. To quantify the effect of the gating system on DE image quality, human observer tests were conducted to measure the magnitude of cardiac artifact under conditions of successful and

  12. Cardiac gating with a pulse oximeter for dual-energy imaging (United States)

    Shkumat, N. A.; Siewerdsen, J. H.; Dhanantwari, A. C.; Williams, D. B.; Paul, N. S.; Yorkston, J.; Van Metter, R.


    The development and evaluation of a prototype cardiac gating system for double-shot dual-energy (DE) imaging is described. By acquiring both low- and high-kVp images during the resting phase of the cardiac cycle (diastole), heart misalignment between images can be reduced, thereby decreasing the magnitude of cardiac motion artifacts. For this initial implementation, a fingertip pulse oximeter was employed to measure the peripheral pulse waveform ('plethysmogram'), offering potential logistic, cost and workflow advantages compared to an electrocardiogram. A gating method was developed that accommodates temporal delays due to physiological pulse propagation, oximeter waveform processing and the imaging system (software, filter-wheel, anti-scatter Bucky-grid and flat-panel detector). Modeling the diastolic period allowed the calculation of an implemented delay, timp, required to trigger correctly during diastole at any patient heart rate (HR). The model suggests a triggering scheme characterized by two HR regimes, separated by a threshold, HRthresh. For rates at or below HRthresh, sufficient time exists to expose on the same heartbeat as the plethysmogram pulse [timp(HR) = 0]. Above HRthresh, a characteristic timp(HR) delays exposure to the subsequent heartbeat, accounting for all fixed and variable system delays. Performance was evaluated in terms of accuracy and precision of diastole-trigger coincidence and quantitative evaluation of artifact severity in gated and ungated DE images. Initial implementation indicated 85% accuracy in diastole-trigger coincidence. Through the identification of an improved HR estimation method (modified temporal smoothing of the oximeter waveform), trigger accuracy of 100% could be achieved with improved precision. To quantify the effect of the gating system on DE image quality, human observer tests were conducted to measure the magnitude of cardiac artifact under conditions of successful and unsuccessful diastolic gating. Six observers

  13. Ability of the Masimo pulse CO-Oximeter to detect changes in hemoglobin. (United States)

    Colquhoun, Douglas A; Forkin, Katherine T; Durieux, Marcel E; Thiele, Robert H


    The decision to administer blood products is complex and multifactorial. Accurate assessment of the concentration of hemoglobin [Hgb] is a key component of this evaluation. Recently a noninvasive method of continuously measuring hemoglobin (SpHb) has become available with multi-wavelength Pulse CO-Oximetry. The accuracy of this device is well documented, but the trending ability of this monitor has not been previously described. Twenty patients undergoing major thoracic and lumbar spine surgery were recruited. All patients received radial arterial lines. On the contralateral index finger, a R1 25 sensor (Rev E) was applied and connected to a Radical-7 Pulse CO-Oximeter (both Masimo Corp, Irvine, CA). Blood samples were drawn intermittently at the anesthesia provider's discretion and were analyzed by the operating room satellite laboratory CO-Oximeter. The value of Hgb and SpHb at that time point was compared. Trend analysis was performed by the four quadrant plot technique, testing directionality of change, and Critchley's polar plot method testing both directionality and magnitude of the change in values. Eighty-eight samples recorded at times of sufficient signal quality were available for analysis. Four quadrant plot analysis revealed 94% of data within the quadrants associated with the correct direction change, and 90% of data points lay within the analysis bounds proposed by Critchley. Pulse CO-Oximetry offers an acceptable trend monitor in patients undergoing major spine surgery. Future work should explore the ability of this device to detect large changes in hemoglobin, as well as its applicability in additional surgical and non-surgical patient populations.

  14. A Single-Chip CMOS Pulse Oximeter with On-Chip Lock-In Detection

    Directory of Open Access Journals (Sweden)

    Diwei He


    Full Text Available Pulse oximetry is a noninvasive and continuous method for monitoring the blood oxygen saturation level. This paper presents the design and testing of a single-chip pulse oximeter fabricated in a 0.35 µm CMOS process. The chip includes photodiode, transimpedance amplifier, analogue band-pass filters, analogue-to-digital converters, digital signal processor and LED timing control. The experimentally measured AC and DC characteristics of individual circuits including the DC output voltage of the transimpedance amplifier, transimpedance gain of the transimpedance amplifier, and the central frequency and bandwidth of the analogue band-pass filters, show a good match (within 1% with the circuit simulations. With modulated light source and integrated lock-in detection the sensor effectively suppresses the interference from ambient light and 1/f noise. In a breath hold and release experiment the single chip sensor demonstrates consistent and comparable performance to commercial pulse oximetry devices with a mean of 1.2% difference. The single-chip sensor enables a compact and robust design solution that offers a route towards wearable devices for health monitoring.

  15. The effect of nail polish and acrylic nails on pulse oximetry reading using the Lifebox oximeter in Nigeria. (United States)

    Desalu, I; Diakparomre, O I; Salami, A O; Abiola, A O


    AIMS AND OBJECTIVES - Pulse oximetry is mandatory during anaesthesia, sedation and transfer of critically ill patients. The effect of nail polish and acrylic nails on the accuracy of saturation reading is inconsistent. The Lifebox pulse oximeter is reliable and recommended for low and middle income countries. We investigated its accuracy in the presence of 4 nail colours and acrylic nails SUBJECTS AND METHODS Fifty non-smoking volunteers had their fingers numbered from right to left (little finger of right hand =1 and little finger of left hand =10). Alternate fingers were nails painted with clear, red, brown and black nail polish and the 5th finger had acrylic nail applied. The corresponding finger on the other hand acted as control. The oxygen saturation was determined using the Lifebox pulse oximeter. Results All fingers (100%) with clear nail polish, red nail polish and acrylic nails recorded a saturation value. Each of the mean saturation value for clear nail polish, red nail polish and acrylic nails was not significantly different from the control mean (p= 0.378, 0.427 and 0.921). Only 12% and 64% of nails polished black and brown respectively recorded a saturation value. The mean SpO- for black and brown polish were significantly different from their control mean (ppolish resulted in a significant decrease in SpO with the Lifebox oximeter. Dark coloured nail polish should be removed prior to SpO2 determination to ensure that accurate readings can be obtained.

  16. A new fibre optic pulse oximeter probe for monitoring splanchnic organ arterial blood oxygen saturation. (United States)

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


    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.

  17. Pulse oximeter using a gain-modulated avalanche photodiode operated in a pseudo lock-in light detection mode (United States)

    Miyata, Tsuyoshi; Iwata, Tetsuo; Araki, Tsutomu


    We propose a reflection-type pulse oximeter, which employs two pairs of a light-emitting diode (LED) and a gated avalanche photodiode (APD). One LED is a red one with an emission wavelength λ = 635 nm and the other is a near-infrared one with that λ = 945 nm, which are both driven with a pulse mode at a frequency f (=10 kHz). Superposition of a transistor-transistor-logic (TTL) gate pulse on a direct-current (dc) bias, which is set so as not exceeding the breakdown voltage of each APD, makes the APD work in a gain-enhanced operation mode. Each APD is gated at a frequency 2f (=20 kHz) and its output signal is fed into a laboratory-made lock-in amplifier that works in synchronous with the pulse modulation signal of each LED at a frequency f (=10 kHz). A combination of the gated APD and the lock-in like signal detection scheme is useful for the reflection-type pulse oximeter thanks to the capability of detecting a weak signal against a large background (BG) light.

  18. Reliability and concurrent validity of a peripheral pulse oximeter and health-app system for the quantification of heart rate in healthy adults. (United States)

    Losa-Iglesias, Marta Elena; Becerro-de-Bengoa-Vallejo, Ricardo; Becerro-de-Bengoa-Losa, Klark Ricardo


    There are downloadable applications (Apps) for cell phones that can measure heart rate in a simple and painless manner. The aim of this study was to assess the reliability of this type of App for a Smartphone using an Android system, compared to the radial pulse and a portable pulse oximeter. We performed a pilot observational study of diagnostic accuracy, randomized in 46 healthy volunteers. The patients' demographic data and cardiac pulse were collected. Radial pulse was measured by palpation of the radial artery with three fingers at the wrist over the radius; a low-cost portable, liquid crystal display finger pulse oximeter; and a Heart Rate Plus for Samsung Galaxy Note®. This study demonstrated high reliability and consistency between systems with respect to the heart rate parameter of healthy adults using three systems. For all parameters, ICC was > 0.93, indicating excellent reliability. Moreover, CVME values for all parameters were between 1.66-4.06 %. We found significant correlation coefficients and no systematic differences between radial pulse palpation and pulse oximeter and a high precision. Low-cost pulse oximeter and App systems can serve as valid instruments for the assessment of heart rate in healthy adults. © The Author(s) 2014.

  19. Optical noninvasive calculation of hemoglobin components concentrations and fractional oxygen saturation using a ring-scattering pulse oximeter (United States)

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


    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.

  20. A practical ultrasonic plethysmograph (United States)

    Wu, V. C.; Nickell, W. T.; Bhagat, P. K.


    An ultrasonic plethysmograph, which gives improved performance over the standard Whitney Strain Gauge, is described. This instrument monitors dimension changes in human limbs by measuring the transit times of acoustic pulses across two chords of the limb. In the case of a small uniform expansion, the percentage change in limb volume is shown to be proportional to twice the percentage change in either of the measured chords. Measurement of two chords allows correction for possible non-uniform expansion. In addition, measurement of two chords allows an estimate of the absolute cross-sectional area of the limb. The developed instrument incorporates a microprocessor, which performs necessary calculation and control functions. Use of the microprocessor allows the instrument to be self-calibrating. In addition, the device can be easily reprogrammed to incorporate improvements in operating features or computational schemes.

  1. Automatic classification of apnea/hypopnea events through sleep/wake states and severity of SDB from a pulse oximeter. (United States)

    Park, Jong-Uk; Lee, Hyo-Ki; Lee, Junghun; Urtnasan, Erdenebayar; Kim, Hojoong; Lee, Kyoung-Joung


    This study proposes a method of automatically classifying sleep apnea/hypopnea events based on sleep states and the severity of sleep-disordered breathing (SDB) using photoplethysmogram (PPG) and oxygen saturation (SpO2) signals acquired from a pulse oximeter. The PPG was used to classify sleep state, while the severity of SDB was estimated by detecting events of SpO2 oxygen desaturation. Furthermore, we classified sleep apnea/hypopnea events by applying different categorisations according to the severity of SDB based on a support vector machine. The classification results showed sensitivity performances and positivity predictive values of 74.2% and 87.5% for apnea, 87.5% and 63.4% for hypopnea, and 92.4% and 92.8% for apnea + hypopnea, respectively. These results represent better or comparable outcomes compared to those of previous studies. In addition, our classification method reliably detected sleep apnea/hypopnea events in all patient groups without bias in particular patient groups when our algorithm was applied to a variety of patient groups. Therefore, this method has the potential to diagnose SDB more reliably and conveniently using a pulse oximeter.

  2. Onboard tagging for real-time quality assessment of photoplethysmograms acquired by a wireless reflectance pulse oximeter. (United States)

    Li, Kejia; Warren, Steve; Natarajan, Balasubramaniam


    Onboard assessment of photoplethysmogram (PPG) quality could reduce unnecessary data transmission on battery-powered wireless pulse oximeters and improve the viability of the electronic patient records to which these data are stored. These algorithms show promise to increase the intelligence level of former "dumb" medical devices: devices that acquire and forward data but leave data interpretation to the clinician or host system. To this end, the authors have developed a unique onboard feature detection algorithm to assess the quality of PPGs acquired with a custom reflectance mode, wireless pulse oximeter. The algorithm uses a Bayesian hypothesis testing method to analyze four features extracted from raw and decimated PPG data in order to determine whether the original data comprise valid PPG waveforms or whether they are corrupted by motion or other environmental influences. Based on these results, the algorithm further calculates heart rate and blood oxygen saturation from a "compact representation" structure. PPG data were collected from 47 subjects to train the feature detection algorithm and to gauge their performance. A MATLAB interface was also developed to visualize the features extracted, the algorithm flow, and the decision results, where all algorithm-related parameters and decisions were ascertained on the wireless unit prior to transmission. For the data sets acquired here, the algorithm was 99% effective in identifying clean, usable PPGs versus nonsaturated data that did not demonstrate meaningful pulsatile waveshapes, PPGs corrupted by motion artifact, and data affected by signal saturation.

  3. [New use of pulse-oximeter as a prophylactic Stimulator to the wearer and a lifesaving tools for prevention of hypoxic mishaps]. (United States)

    Morioka, Tohru; Terasaki, Hidenori


    Pulse-oximeter has been widely used for the clinical assessment of physical status of a patient and as an alarming tool of hypoxia to medical personnel at the bedside or in the observation center. However, it has never been used for direct stimulation of the wearer. We considered innovation of pulse-oximeter as a prophylactic alarm-oximeter for the wearer. If SPO2 goes down to unfavorable level, the alarm-oximeter starts to send signal through a control box to a stimulator, such as an electrical nerve stimulator, a cold thermal tip, or mechanical device like a vibrator or compressor. The dermal stimulator is usually fixed to the right or left wrist with a Velcro band. The control box is affixed to the wristband by using Velcro. The alarm may be sent to an earphone or speaker with a verbal command like "take a deep breath". Alarm-oximeter will be combined to an oxygen inhaler or mechanical ventilatory assist device, or a drug administration system through electric line or wireless transmitter to start or change its function before the arrival of medical personnel. It will prevent hypoxic mishaps during medical intervention or sleep apnea syndrome. It will be also applicable to stop snoring.

  4. Phantom with Pulsatile Arteries to Investigate the Influence of Blood Vessel Depth on Pulse Oximeter Signal Strength

    Directory of Open Access Journals (Sweden)

    Hunor Santha


    Full Text Available This paper describes a three-layer head phantom with artificial pulsating arteries at five different depths (1.2 mm, 3.7 mm, 6.8 mm, 9.6 mm and 11.8 mm. The structure enables formation of spatially and temporally varying tissue properties similar to those of living tissues. In our experiment, pressure pulses were generated in the arteries by an electronically controlled pump. The physical and optical parameters of the layers and the liquid in the artificial arteries were similar to those of real tissues and blood. The amplitude of the pulsating component of the light returning from the phantom tissues was measured at each artery depth mentioned above. The build-up of the in-house-developed pulse oximeter used for performing the measurements and the physical layout of the measuring head are described. The radiant flux generated by the LED on the measuring head was measured to be 1.8 mW at 910 nm. The backscattered radiant flux was measured, and found to be 0.46 nW (0.26 ppm, 0.55 nW (0.31 ppm, and 0.18 nW (0.10 ppm for the 1.2 mm, 3.7 mm and 6.8 mm arteries, respectively. In the case of the 9.6 mm and 11.8 mm arteries, useful measurement data were not obtained owing to weak signals. We simulated the phantom with the arteries at the above-mentioned five depths and at two additional ones (2.5 mm and 5.3 mm in depth using the Monte Carlo method. The measurement results were verified by the simulation results. We concluded that in case of 11 mm source-detector separation the arteries at a depth of about 2.5 mm generate the strongest pulse oximeter signal level in a tissue system comprising three layers of thicknesses: 1.5 mm (skin, 5.0 mm (skull, and > 50 mm (brain.

  5. The design of software system of pulse oximeter%脉搏式血氧饱和度仪的软件系统的研制

    Institute of Scientific and Technical Information of China (English)

    谭小丹; 陈亚明; 邓亲恺


    本文介绍自行研制的脉搏式血氧饱和度仪的软件系统。该软件系统基于Franklin C语言,运用自动基线调节,可调积分放大,线性回归等方法,使该血氧饱和度仪达到临床监护的要求。%A software system of the pulse oximeter is presented in this paper. Based on Franklin C, this software system includes three main parts, one part is to automatically regulates the base line of signal, the second part is a controlled integral module,and the third part is a digital signal processing module. As the result, the pulse oximeter is satisfactory to clinical monitoring.

  6. Effects of divided attention and operating room noise on perception of pulse oximeter pitch changes: A laboratory study (United States)

    Stevenson, Ryan A.; Fellow, Postdoctoral; Schlesinger, Joseph J.; Physician, Resident; Wallace, Mark T.


    Background Anesthesiology requires performing visually-oriented procedures while monitoring auditory information about a patient’s vital signs. A concern in operating rooms environments is the amount of competing information and the effects that divided attention have on patient monitoring, such as detecting auditory changes in arterial oxygen saturation via pulse oximetry. Methods We measured the impact of visual attentional load and auditory background noise on the ability of anesthesia residents to monitor the pulse oximeter auditory display in a laboratory setting. Accuracies and response times were recorded reflecting anesthesiologists’ abilities to detect changes in oxygen saturation across three levels of visual attention in quiet and with noise. Results Results show that visual attentional load substantially impacts the ability to detect changes in oxygen saturation levels conveyed by auditory cues signaling 99 and 98% saturation. These effects are compounded by auditory noise, with up to a 17% decline in performance. These deficits are seen in the ability to accurately detect a change in oxygen saturation and in speed of response. Conclusions Most anesthesia accidents are initiated by small errors that cascade into serious events. Lack of monitor vigilance and inattention are two of the more commonly cited factors. Reducing such errors is thus a priority for improving patient safety. Specifically, efforts to reduce distractors and lower background noise should be considered during induction and emergence, periods of especially high risk, when anesthesiologists must attend to many tasks and are thus susceptible to error. PMID:23263015

  7. Design of Pulse Oximeter with WiFi Connectivity and Interoperability with Standard HL7 and IEEE 11073-10404:2008

    Directory of Open Access Journals (Sweden)

    Víctor Ochoa


    Full Text Available Given that health is so relevant for global productivity and competitiveness, and that the Information and Communications Technology (ICTs play an important role in all of the productivity factors, this work makes use of the ICTs in health matters proposing the to use a WiFi oximeter. This article describes the operating principles of a Pulse Oximeter (PO which is an opto-electronic non-invasive medical instrument capable of measuring changes in heart rate (HR and SpO2 at the fingertip and its upgrade to the standards; HL7 and IEEE 11073-10404:2008, its design, and its validation against the three existing devices. Variables (SpO2%, Ppm and Temperature were compared, and its performance and impact were discussed the addition of the WiFi technology allows a better communication between devices, causing a greater impact in global competiveness.

  8. High sensitive pulse oximeter-spectrophotometer for laser-optical dosimetry in biology and medicine (United States)

    Asimov, M. M.; Asimov, R. M.; Rubinov, A. N.; Mamilov, S. A.; Plaksiy, Yu. S.


    High sensitive multi channel pulse oxymeter - spectrophotometer for control of the local tissue oxygen saturation is presented. Due to an original method of data storing and processing the accuracy of measurements 3-4 times are increased in compare with similar systems. This system is used for registration of the local changes of arterial blood saturation with oxygen under effect of low intensity laser radiation. It is shown that the photodissociation of oxyhemoglobin in cutaneous blood vessels play a dominant role in the mechanism of biostimulating and therapeutic effect of low intensity laser radiation. The results of experimental investigation in vivo the dependence of arterial oxygen blood saturation on temperature and the wavelength of laser radiation are presented. It is suggested that dosimetry for laser therapy could be base on regulation of local concentration of free oxygen in tissue.

  9. Design and implementation of a sigma delta technology based pulse oximeter's acquisition stage (United States)

    Rossi, E. E.; Peñalva, A.; Schaumburg, F.


    Pulse oximetry is a widely used tool in medical practice for estimating patient's fraction of hemoglobin bonded to oxygen. Conventional oximetry presents limitations when changes in the baseline, or low amplitude of signals involved occur. The aim of this paper is to simultaneously solve these constraints and to simplify the circuitry needed, by using ΣΔ technology. For this purpose, a board for the acquisition of the needed signals was developed, together with a PC managed software which controls it, and displays and processes in real time the information acquired. Also laboratory and field tests where designed and executed to verify the performance of this equipment in adverse situations. A simple, robust and economic instrument was achieved, capable of obtaining signals even in situations where conventional oximetry fails.

  10. Invasive versus noninvasive hemoglobin measurement by pulse CO-Oximeter in neonates admitted to NICU

    Directory of Open Access Journals (Sweden)

    Hetal Vora


    Full Text Available Background Total haemoglobin measurement (tHb is one of the most commonly performed laboratory tests in patients admitted to the neonatal intensive care unit (NICU. Non invasive haemoglobin measurement is possible. In neonates this method can reduce iatrogenic blood loss. Studies performed in adults to compare haemoglobin (Hb obtained with the use of non-invasive Hb monitor and laboratory method has shown a clinically acceptable accuracy of non-invasive Hb measurements.(1 Masimo Rainbow SET, Pulse CO‐oximetry developed by Masimo Corporation leverages 7 wavelengths and advanced signal processing technique to measure total haemoglobin (SpHb values. The haemoglobin values measured through monitor is displayed continuously. This improves quality of care in babies by non invasive way. The monitor measures both pulse oximetry and SpHb with single probe which makes it advantageous (2 Objective. To compare transcutaneously spectroscopically measured hemoglobin values with venous hemoglobin values in neonates admitted to NICU. Study Design Prospective study in healthy preterm and term infants who were hemodynamically stable. Results Recordings were obtained from 76 stable infants (median gestational age at measurement: 36 weeks [range: 34–43 weeks]; median body weight: 1890 g [range: 1095–4360 g]. The spectroscopic haemoglobin values were corrected for inhomogeneous distribution of haemoglobin in the tissue. The venous and spectroscopic haemoglobin values were then compared by using the Bland- Altman method, which gave an error of <5%. Conclusions This is a good relation between the 2 methods for measuring haemoglobin. Larger studies are required to validate this non invasive method in those with conditions that affects the perfusion.

  11. An in vitro quantification of pressures exerted by earlobe pulse oximeter probes following reports of device-related pressure ulcers in ICU patients . (United States)

    Goodell, Teresa T


    The earlobe often is used to monitor perfusion when pulse oximeter signal quality is impaired in the fingers and toes. Prompted by intermittent occurrences of roughly circular earlobe pressure ulcers among patients in intensive care units, a convenience sample of seven calibrated pulse oximeter probes was used to quantify earlobe pressure exerted by these devices in vitro. All were tested twice with an electronic load cell, a strain gauge with a transducer that transforms the measured force into a readable numerical signal. The probe was clipped to the load cell just as it is clipped to the earlobe in the clinical setting. The probes exerted an average of 0.24 lb (SD 0.6) of force over an area of 0.3 square inches, equal to an average of 20.7 mm Hg (SD 0.6) pressure on tissue. This value exceeds some empirically derived values of capillary perfusion pressure. The occurrence of device-related pressure ulcers, as well pressure ulcers on the ears, has been documented, but little is known about device-related earlobe pressure ulcers or the actual pressure exerted by these devices. Additional in vitro studies are needed to quantify the pressures exerted by these and other probes, and future prevalence and incidence studies should include more detailed pressure ulcer location and device use documentation. Until more is known about the possible role of these devices in the development of pressure ulcers, clinicians should be cognizant of their potential for causing pressure ulcers, particularly in patients whose conditions can compromise skin integrity.

  12. An ultrasonic plethysmograph for space flight applications (United States)

    Bhagat, P. K.; Lafferty, J. F.; Bowman, D.; Kadaba, M. P.


    The development of an ultrasonic plethysmograph based on the transit time measurement principle is reported, which meets the space-imposed requirements for evaluating cardiovascular deconditioning. It consists of a pulse generator, pulse receiver amplifier, voltage comparator, synchronous pulse generator, elapsed time counter, and transmit and receive piezoelectric crystals resonant at 2 MHz and of 3 mm diameter. The transit time for an ultrasonic pulse to propagate across a limb cross section is computed in a digital fashion using a 32 MHz clock, and resolution is 0.049 mm with the range being approximately 200 mm. Experimental results regarding dynamic system response were found comparable in both accuracy and sensitivity to those of a Whitney strain gage using a 50 torr venous occlusion.

  13. 基于C8051F120的透射式脉搏血氧仪的设计%Design of transmission pulse oximeter based on C8051F120

    Institute of Scientific and Technical Information of China (English)

    方启超; 周严


    Pulse oximeter plays an important role in clinical practice because of it's continuous, non-invasive, rapid and accurate monitoring for the human arterial oxygen saturation and heart rate. This paper introduces the hardware and software design which based on the Lambert-Beer law, choice the adult finger clip Spo2 probe format the system of microcontroller,complete the detection of the arterial oxygen saturation. Six people use the designed pulse oximeter to measure the oxygen saturation, the test results show that the pulse oximeter has met the design requirements and complete the expected functionality, the results show that the oximeter measurement of the arterial oxygen saturation and pulse rate values accurate,the pulse waveform is available.%脉搏血氧仪具有连续、无创、快速、准确监测人体动脉血氧饱和度和心率的功能,在临床上具有重要作用.以朗伯比尔定律为理论基础,采用成人指夹式血氧探头为传感器,以C8051F120单片机组建微处理器系统,进行了血样检测的软硬件设计,实现了血氧饱和度检测.使用设计的脉搏血氧仪对6名受试者进行血氧测试,结果表明该血氧仪测量的血氧饱和度值和脉率值准确,脉搏波波形可用.

  14. Comparative Study of Pulp Vitality in Primary and Young Permanent Molars in Human Children with Pulse Oximeter and Electric Pulp Tester (United States)

    Sood, PB; Sharma, Arun; Madan, Manish; Shahi, Nishat; Gandhi, Geetanjali


    ABSTRACT Aim and objective: The purpose of this study was to compare the pulp testing methods (pulse oximetry and electric pulp test) in primary and young permanent teeth of children. Materials and methods: The study included a total of 155 children aged 4 to 15 years. Twenty children formed control group I. Study group included all healthy, 85 primary 2nd molars in group II and 85 permanent 1st molars in group III. Fifty children needing endodontics treatment formed test group IV. The readings were recorded as true positive (TP), false positive (FP), true negative (TN), false negative (FN). Based on this, the sensitivity, specificity, positive predictive value and negative predictive value were calculated for each method. The results were statistically analyzed using Chi-square test. Results: On comparing pulse oximetry with electric pulp test ‘p-value’ was found to be 0.487 and 1.00 for groups 1 and 2 respectively and was statistically not significant. Whereas ‘p-value’ for groups 3 and 4 was < 0.0001 and 0.003 respectively and was statistically highly significant. Conclusion: The present study indicates that pulse oximetry can be used as a routine method for assessing the pulp vitality in primary, young permanent and mature permanent teeth. How to cite this article: Shahi P, Sood PB, Sharma A, Madan M, Shahi N, Gandhi G. Comparative Study of Pulp Vitality in Primary and Young Permanent Molars in Human Children with Pulse Oximeter and Electric Pulp Tester. Int J Clin Pediatr Dent 2015;8(2):94-98. PMID:26379374

  15. 基于容积脉搏波的无创连续血压测量系统%A Non-invasive Continuous Blood Pressure Measurement System Based on Plethysmographic Pulse Wave

    Institute of Scientific and Technical Information of China (English)

    梁永波; 陈真诚; 朱健铭; 殷世民


    Objective To develop a non-invasive continuous blood pressure measurement system without the cuff based on plethysmographic pulse wave. Methods A blood pressure estimation equation was established by the stepwise regression analysis on blood pressure and pulse wave transit time which was extracted from a single circle of plethysmographic pulse wave, and then the non-invasive continuous blood pressure measurement was realized. Results Compared blood pressure value with detection by the system and Yu-Yue brand mercury sphygmomanometer from various populations, the results indicated that the two methods exhibit good coherence , and the measurement error is better than the Association for the Advancement of Medical Instrumentation (AAMI) recommendation standard. Conclusion Compared with traditional blood pressure measurement method , the non-invasive continuous blood pressure measurement method is more convenient. It can measure blood pressure continuously without cuff and invasion, and may have promising application in the future.%目的 设计一种基于容积脉搏波的无袖套连续血压测量系统.方法 从单一容积脉搏波中提取脉搏波传导时间,经逐步回归分析与血压建立血压估算方程,实现无创连续血压测量.结果 通过对不同人群血压检测,并与鱼跃牌水银血压计进行对比,结果表明该方法和传统方法具有较好的测试一致性,测量误差优于美国医疗仪器促进协会(AAMI)推荐标准.结论 该方法同传统血压测量方法相比,测量方便,可彻底摆脱缚带,并能实现无创连续测量,具有更广阔的应用前景.

  16. Pulse oximeter accuracy and precision at five different sensor locations in infants and children with cyanotic heart disease

    Directory of Open Access Journals (Sweden)

    Jyotirmoy Das


    Full Text Available Since the invention of pulse oximetry by Takuo Aoyagi in the early 1970s, its use has expanded beyond the perioperative care into neonatal, paediatric and adult intensive care units (ICUs. Pulse oximetry is one of the most important advances in respiratory monitoring as its readings (SpO 2 are used clinically as an indirect estimation of arterial oxygen saturation (SaO 2 . Sensors were placed frequently on the sole, palm, ear lobe or toes in addition to finger. On performing an extensive Medline search using the terms "accuracy of pulse oximetry" and "precision of pulse oximetry", limited data were found in congenital heart disease patients in the immediate post-corrective stage. Also, there are no reports and comparative data of the reliability and precision of pulse oximetry when readings from five different sensor locations (viz. finger, palm, toe, sole and ear are analysed simultaneously. To fill these lacunae of knowledge, we undertook the present study in 50 infants and children with cyanotic heart disease in the immediate post-corrective stage.

  17. 基于iOS平台的脉搏血氧仪设计与实现%Design and implementation of pulse oximeter based on iOS

    Institute of Scientific and Technical Information of China (English)

    张历; 段发阶; 李超


    Oxygen saturation monitoring has very important significance to the human health. In order to achieve oxygen saturation wireless measurement and remote sharing, this essay presents a pulse oximeter system based on iOS. The sys-tem utilizes MCU CC2540 which integrates low-power Bluetooth protocol stack for photoplethysmography signal acquisi-tion and uses Bluetooth protocol stack to upload real-time data to iOS, then uses iOS to calculate the oxygen saturation and pulse rate according to the modified Lambert-Beer law, ultimately the measurement results will be uploaded to the cloud server. Experimental results show that this system has achieved noninvasive oximetry monitoring, pulse wave data storage, measurement results uploading to cloud server and can share measurements.%血氧饱和度的监测对生理健康具有极为重要的意义,为了实现对人体血氧饱和度的无线测量和远程分享,提出了一种基于iOS操作系统的脉搏血氧饱和度测量系统。该系统利用集成了低功耗蓝牙协议栈的单片机CC2540对光电容积脉搏波信号进行采集,使用蓝牙传输协议把数据实时的上传到iOS操作系统,利用iOS操作系统对信号进行数字信号处理,根据修正的朗伯-比尔定律计算出血氧饱和度和脉率,最终把测量结果上传到云端服务器。实验结果表明,该系统可以实现血氧饱和度的无创实时监测、脉搏波数据的存储、测量结果上传云端服务器和分享测量结果的功能。

  18. Infrared parietal colorectal flowmetry: a new application of the pulse oximeter. Is this method useful for general surgeons in preventing anastomotic leakage after colorectal resections?

    Directory of Open Access Journals (Sweden)

    Delfrate R


    Full Text Available Roberto Delfrate,1 Massimo Bricchi,1 Paolo Forti,1 Claude Franceschi2 1Surgery Unit, Figlie Di San Camillo Hospital, Cremona, Italy; 2Vascular Exploration Service, St Joseph Hospital, Paris, France Background: Anastomotic leak is a major complication of colorectal surgery. Among the causes of dehiscence, anastomotic ischemia seems to be fundamental and consequently so is the evaluation of the parietal flow. We proposed a new application of infrared flowmeter for the evaluation of the parietal flow at the stumps after colon resection. Objective: The aim of this study is to assess the feasibility of using an intraoperative intestinal wall flowmeter to assess arterial capillary flow in order to avoid the execution of anastomoses in poorly vascularized segments of bowel, and consequently to reduce the risk of anastomotic leakage.Methods: Retrospective analysis of two groups of patients with different methods of evaluation of colon resection stump vascularization. Ninety-two consecutive patients (Group A underwent surgical colorectal resection for cancer. In this group, we used a pulse-oximetry sensor to assess the parietal flow: once the magnitude of the colon resection was established according to surgical and oncological criteria, the exact location of the resection was adjusted according to the parietal flowmetry curve. This method was compared with 139 consecutive colorectal resections (Group B in which vascularization was assessed by checking the pulsatility of the mesenteric arteries, macroscopic wall resection stump appearance, and bleeding of the wall stump. The main outcome measure was the reduction in anastomotic dehiscence.Results: In Group A no anastomotic leakage occurred (0/92. Conversely, in Group B six anastomotic leaks occurred (6/139. The statistical analysis of the two groups thanks to the Fisher's exact test shows that P<0.05, which is statistically significant.Conclusion: We tested a new application of the pulse oximeter: the

  19. Comparison of arterial pressure and plethysmographic waveform-based dynamic preload variables in assessing fluid responsiveness and dynamic arterial tone in patients undergoing major hepatic resection

    NARCIS (Netherlands)

    Vos, J. J.; Kalmar, A. F.; Struys, M. M. R. F.; Wietasch, J. K. G.; Hendriks, H. G. D.; Scheeren, T. W. L.


    Dynamic preload variables to predict fluid responsiveness are based either on the arterial pressure waveform (APW) or on the plethysmographic waveform (PW). We compared the ability of APW-based variations in stroke volume (SVV) and pulse pressure (PPV) and of PW-based plethysmographic variability in

  20. Comparison of arterial pressure and plethysmographic waveform-based dynamic preload variables in assessing fluid responsiveness and dynamic arterial tone in patients undergoing major hepatic resection

    NARCIS (Netherlands)

    Vos, J. J.; Kalmar, A. F.; Struys, M. M. R. F.; Wietasch, J. K. G.; Hendriks, H. G. D.; Scheeren, T. W. L.

    Dynamic preload variables to predict fluid responsiveness are based either on the arterial pressure waveform (APW) or on the plethysmographic waveform (PW). We compared the ability of APW-based variations in stroke volume (SVV) and pulse pressure (PPV) and of PW-based plethysmographic variability

  1. Comparison of arterial pressure and plethysmographic waveform-based dynamic preload variables in assessing fluid responsiveness and dynamic arterial tone in patients undergoing major hepatic resection

    NARCIS (Netherlands)

    Vos, J. J.; Kalmar, A. F.; Struys, M. M. R. F.; Wietasch, J. K. G.; Hendriks, H. G. D.; Scheeren, T. W. L.


    Dynamic preload variables to predict fluid responsiveness are based either on the arterial pressure waveform (APW) or on the plethysmographic waveform (PW). We compared the ability of APW-based variations in stroke volume (SVV) and pulse pressure (PPV) and of PW-based plethysmographic variability in

  2. Systematic review and meta-analysis of method comparison studies of Masimo pulse co-oximeters (Radical-7™ or Pronto-7™) and HemoCue® absorption spectrometers (B-Hemoglobin or 201+) with laboratory haemoglobin estimation. (United States)

    Hiscock, R; Kumar, D; Simmons, S W


    We assessed agreement in haemoglobin measurement between Masimo pulse co-oximeters (Rad-7™ and Pronto-7™) and HemoCue® photometers (201+ or B-Hemoglobin) with laboratory-based determination and identified 39 relevant studies (2915 patients in Masimo group and 3084 patients in HemoCue group). In the Masimo group, the overall mean difference was -0.03 g/dl (95% prediction interval -0.30 to 0.23) and 95% limits of agreement -3.0 to 2.9 g/dl compared to 0.08 g/dl (95% prediction interval -0.04 to 0.20) and 95% limits of agreement -1.3 to 1.4 g/dl in the HemoCue group. Only B-Hemoglobin exhibited bias (0.53, 95% prediction interval 0.27 to 0.78). The overall standard deviation of difference was larger (1.42 g/dl versus 0.64 g/dl) for Masimo pulse co-oximeters compared to HemoCue photometers. Masimo devices and HemoCue 201+ both provide an unbiased, pooled estimate of laboratory haemoglobin. However, Masimo devices have lower precision and wider 95% limits of agreement than HemoCue devices. Clinicians should carefully consider these limits of agreement before basing transfusion or other clinical decisions on these point-of-care measurements alone.

  3. Low-Cost Embedded Oximeter (United States)

    Laghrouche, M.; Haddab, S.; Lotmani, S.; Mekdoud, K.; Ameur, S.


    Nowadays, many medical devices have been developed for the purposes of diagnosing and treatment. Wearable sensors and systems have evolved to the point that they can be considered ready for clinical application. The use of wearable monitoring devices that allow continuous or intermittent monitoring of physiological signals is critical for the advancement of both the diagnosis as well as treatment of diseases. Patient vital sign monitoring within hospitals requires the use of noninvasive sensors that are hardwired to bedside monitors. This paper describes the initial bench testing of a wireless wearable pulse oximeter. Arterial oxygen saturation in the patient's blood signal was measured with an optical sensor, and then converted to digital data using a microcontroller system. The digital data were then sent to a receiver where it is in 433 MHz FM/FSK transmitter. At the receiver, the digital data were reconverted to analog signal to be monitored and recorded on the PC.

  4. 21 CFR 870.2700 - Oximeter. (United States)


    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Oximeter. 870.2700 Section 870.2700 Food and Drugs... CARDIOVASCULAR DEVICES Cardiovascular Monitoring Devices § 870.2700 Oximeter. (a) Identification. An oximeter is... conjunction with a fiberoptic oximeter catheter. (b) Classification. Class II (performance standards)....

  5. 基于光-频率转换器的高精度数字脉搏血氧仪的设计%Design of Digital Pulse Oximeter with High Resolution Based on Optical-Frequency Converter

    Institute of Scientific and Technical Information of China (English)

    杨涛; 林宛华; 翁羽洁; 杨玲; 吴小玲


    针对目前脉搏血氧仪进口成本高、功耗大、抗干扰差、检测范围小等问题,本文给出了一种低成本低功耗的数字脉搏血氧仪设计方法.采用基于光-频率转换器的高分辨数字探头提高精度和检测范围,移植直流跟踪滤波器去基线漂移提高抗干扰能力,利用上升沿和下降沿检测脉率算法提高检测准确率.本设计在人体小幅运动及手指轻度抖动时,仍能得到稳定的脉搏波形和脉率,通过使用Fluke Index2型血氧模拟仪在不同条件下进行重复实验,发现血氧饱和度为35%~100%时精度为1%、弱灌注量小于等于0.2%时精度达到4%;脉率检测的误差小于1.表明此设计在高精度、大范围、重复性和抗抖动方面均有所改善,适合于家庭、社区等医用监护场合使用.%Due to pulse oximeters have some disadvantages such as high cost of import, high power consumption , poor interference immunization , and small detection range. In this study , we presented a kind of digital pulse oximeter with low cost and power consumption. A digital detector based on light-frequency converter and with high resolution was adopted to improve precision and detection range , A DC tracking filter was used to cancel baseline drift to improve anti-interference ability , and a pulse rate detection algorithm using rising and falling edge was utilized to improve detection accuracy. In this study, stable pulse waveform and pulse rate could still be captured when body moved gently and fingers trembled slightly. After repeating the experiment under different conditions by Fluck Index2 oximeter simulator, we found that the accuracy was l% when oxygen saturation was 35% to 100 % , the accuracy was 4% when low perfusion was smaller than or equal to 0. 2% ; and the pulse rate error is less than 1. In this study , the design had been improved in aspects of high precision, large scale , repetitiveness and anti-jitter. It is suitable for

  6. Software method for extracting photoplethysmography in pulse oximeter%脉搏血氧仪中光电容积脉搏波的软件检出方法

    Institute of Scientific and Technical Information of China (English)

    张虹; 孙卫新; 金捷


    脉搏血氧仪中光电容积脉搏波的正确提取和检出是完成氧饱和度测量任务的主要环节之一. 为了克服传统设计中采用硬件电路完成脉搏波提取和检出时所带来的系统整体设计复杂,稳定性和重复性差等缺点,作者研究了光电容积脉搏波的软件提取和检出方法,为脉搏血氧饱和度检测系统的数字化设计奠定了基础.%Correct extraction of the photoplethysmography is one of the primary procedures to measure the oxygen saturation in the pulse oximeter. In order to overcome the problems of complex system design, instability and bad repetition which are brought about by analog circuits for completing the photoplethysmography extraction in conventional pulse oximetry systems, the author studied the software method to extract the photoplethysmography which will be the basis for digitizing the design of the pulse oximetry systems.

  7. Design of a Pulse Oximeter Used to Low Perfusion and Low Oxygen Saturation%一种可用于低灌注和低血氧测量的脉搏血氧仪的设计

    Institute of Scientific and Technical Information of China (English)

    谭双平; 艾志光; 杨玉星; 谢庆国


    This paper presents a new pulse oximeter used to low perfusion at 0.125%and wide oxygen saturation range from 35%to 100%. In order to acquire the best PPG signals, the variable gain amplifier(VGA) is adopted in hardware. The self-developed auto-correlation modeling method is adopted in software and it can extract pulse wave from low perfusion signals and remove motion artifacts partly.%  设计了一种能在低灌注和低血氧条件下准确测量的脉搏血氧仪,将低灌注检测能力和SpO2的测量范围分别扩展至0.125%和35%~100%。在硬件方面使用数字可控的可变增益放大器来获得最佳的光电容积图信号;在软件方面使用了自主开发的自相关建模法的低灌注SpO2测量算法,能有效从低灌注信号中提取脉搏波信号,且对运动干扰也有一定的抑制能力。

  8. 控制性缺氧条件下国产脉搏血氧饱和度仪的准确度研究%The study of the accuracy of domestic pulse oximeter under controlled hypoxemia

    Institute of Scientific and Technical Information of China (English)

    李璐; 古妙宁; 肖金仿; 刘晓军; 张旖旎; 刘高望; 张雅婷; 解春艳


    目的 研究国产脉搏血氧饱和度仪(pulse oximeter,POM)在健康志愿者控制性缺氧条件下的准确度及特点,为临床安全、有效使用提供依据. 方法 通过吸入氧氮混合气体使健康志愿者处于缺氧状态,相同型号的POM采用Masimo和Nellcor两种脉氧探头同时监测脉搏血氧饱和度(pulse oxygen saturation,SpO2),监测SpO2区间为70%~ 100%,在>95%、92%、85%、78%、70%这5个目标值的区间内记录SpO2数值,并在相应时点抽动脉血行血气分析作对照. 结果 Masimo和Nellcor两种脉氧探头所测的70%~ 100%范围内的SpO2与血气分析所测的动脉血氧饱和度(arterial oxygen saturation,SaO2)相对照,差异都在标准范围内(Arms分别为2.16和2.32),Masimo探头的偏差(SpO2-SaO2)在≥80%和<80%时分别为0.93%和-1.45%,Nellcor探头则分别为0.16%和-1.91%,且两种探头差异有统计学意义(P<0.01). 结论 使用Masimo和Nellcor探头的国产POM均能准确反映不同缺氧程度下的血氧饱和度情况,但两者由于原理的不同而存在差异,Nellcor探头读数普遍低于Masimo探头读数;随着SpO2读数下降,偏差朝着负值逐渐增大,即容易低估SaO2,在SpO2<80%时更加明显.%Objective To study the accuracy and characteristic of domestic pulse oximeter(POM) used in healthy volunteers under controlled hypoxemia,and to provide scientific proof for safe and effective clinical application.Methods Healthy voluntee were made hypoxic by inhaling mix gases of oxygen and nitrogen,and were monitored by two pulse oximeters with Masimo and Nellcor pulse probe,respectively.Monitoring interval of pulse oxygen saturation (SpO2) was 70% to 100%.When it reached around the five target values (>95%,92%,85%,78%,70%),readings of SpO2 were recorded and arterial blood sample were collected at exactly the same time for blood gas analysis.Results Differences of SpO2 detected by Masimo and Nellcor probes

  9. Development of an oximeter for neurology (United States)

    Aleinik, A.; Serikbekova, Z.; Zhukova, N.; Zhukova, I.; Nikitina, M.


    Cerebral desaturation can occur during surgery manipulation, whereas other parameters vary insignificantly. Prolonged intervals of cerebral anoxia can cause serious damage to the nervous system. Commonly used method for measurement of cerebral blood flow uses invasive catheters. Other techniques include single photon emission computed tomography (SPECT), positron emission tomography (PET), magnetic resonance imaging (MRI). Tomographic methods frequently use isotope administration, that may result in anaphylactic reactions to contrast media and associated nerve diseases. Moreover, the high cost and the need for continuous monitoring make it difficult to apply these techniques in clinical practice. Cerebral oximetry is a method for measuring oxygen saturation using infrared spectrometry. Moreover reflection pulse oximetry can detect sudden changes in sympathetic tone. For this purpose the reflectance pulse oximeter for use in neurology is developed. Reflectance oximeter has a definite advantage as it can be used to measure oxygen saturation in any part of the body. Preliminary results indicate that the device has a good resolution and high reliability. Modern applied schematics have improved device characteristics compared with existing ones.

  10. Microprocessor-controlled ultrasonic plethysmograph (United States)

    Bhagat, P. K.; Wu, V. C.


    Safe, nonintrusive microprocessor system times ultrasonic pulses to measure limb cross-sectional area. Simple instrument requires no calibration and does not confine leg movement, making tests relating limb volume to activity level possible. Program considers more realistic geometries of human limb than circular cross-sections and monitors changes in area with great accuracy. Errors due to body temperature changes and timing roundoff are insignificant.

  11. Pulse oximetry recorded from the Phone Oximeter for detection of obstructive sleep apnea events with and without oxygen desaturation in children. (United States)

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


    Obstructive sleep apnea (OSA) disrupts normal ventilation during sleep and can lead to serious health problems in children if left untreated. Polysomnography, the gold standard for OSA diagnosis, is resource intensive and requires a specialized laboratory. Thus, we proposed to use the Phone Oximeter™, a portable device integrating pulse oximetry with a smartphone, to detect OSA events. As a proportion of OSA events occur without oxygen desaturation (defined as SpO2 decreases ≥ 3%), we suggest combining SpO2 and pulse rate variability (PRV) analysis to identify all OSA events and provide a more detailed sleep analysis. We recruited 160 children and recorded pulse oximetry consisting of SpO2 and plethysmography (PPG) using the Phone Oximeter™, alongside standard polysomnography. A sleep technician visually scored all OSA events with and without oxygen desaturation from polysomnography. We divided pulse oximetry signals into 1-min signal segments and extracted several features from SpO2 and PPG analysis in the time and frequency domain. Segments with OSA, especially the ones with oxygen desaturation, presented greater SpO2 variability and modulation reflected in the spectral domain than segments without OSA. Segments with OSA also showed higher heart rate and sympathetic activity through the PRV analysis relative to segments without OSA. PRV analysis was more sensitive than SpO2 analysis for identification of OSA events without oxygen desaturation. Combining SpO2 and PRV analysis enhanced OSA event detection through a multiple logistic regression model. The area under the ROC curve increased from 81% to 87%. Thus, the Phone Oximeter™ might be useful to monitor sleep and identify OSA events with and without oxygen desaturation at home.

  12. Quantitative clinical nonpulsatile and localized visible light oximeter: design of the T-Stat tissue oximeter (United States)

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


    We report the development of a general, quantitative, and localized visible light clinical tissue oximeter, sensitive to both hypoxemia and ischemia. Monitor design and operation were optimized over four instrument generations. A range of clinical probes were developed, including non-contact wands, invasive catheters, and penetrating needles with injection ports. Real-time data were collected (a) from probes, standards, and reference solutions to optimize each component, (b) from ex vivo hemoglobin solutions co-analyzed for StO2% and pO2 during deoxygenation, and (c) from normoxic human subject skin and mucosal tissue surfaces. Results show that (a) differential spectroscopy allows extraction of features with minimization of the effects of scattering, (b) in vitro oximetry produces a hemoglobin saturation binding curve of expected sigmoid shape and values, and (c) that monitoring human tissues allows real-time tissue spectroscopic features to be monitored. Unlike with near-infrared (NIRS) or pulse oximetry (SpO2%) methods, we found non-pulsatile, diffusion-based tissue oximetry (StO2%) to work most reliably for non-contact reflectance monitoring and for invasive catheter- or needle-based monitoring, using blue to orange light (475-600 nm). Measured values were insensitive to motion artifact. Down time was non-existent. We conclude that the T-Stat oximeter design is suitable for the collection of spectroscopic data from human subjects, and that the oximeter may have application in the monitoring of regional hemoglobin oxygen saturation in the capillary tissue spaces of human subjects.

  13. [Application of retinal oximeter in ophthalmology]. (United States)

    Li, Jing; Ma, Jianmin; Wang, Ningli


    Retinal oximeter is a new machine which has been used in the diagnose, treatment and research of several ophthalmic diseases for recent years. It allows ophthalmologists to gain retinal oxygen saturation directly. Therefore, retinal oximeter might be useful for ophthalmologists to understand ophthalmic diseases more deeper and clarify the impact of ischemia on retinal function. It has been reported in the literatures that retinal oximeter has potentially useful diagnostic and therapeutic indications in various eye diseases such as diabetic retinopathy, central retinal vein and artery occlusion, retinitis pigmentosa, glaucomatous optic neuropathy, et al. In this thesis, the application of retinal oximeter in ophthalmology is reviewed.

  14. Impedance plethysmographic observations in thoracic outlet syndrome.

    Directory of Open Access Journals (Sweden)

    Nerurkar S


    Full Text Available Forty patients with symptoms of neuro-vascular compression in the upper extremities were subjected to impedance plethysmographic study using Parulkar′s method. Two patients recorded decreased blood flow (BFI in supine position and were diagnosed as having partial occlusion at subclavian level. Sixteen of the patients recorded decreased BFI on 90 degrees abduction and hyper-abduction. Twelve of these patients had radiological evidence of anomalous cervicle ribs. In remaining four patients extrinsic impression on the subclavian artery due to fibrous deposits was confirmed by arteriography. Remaining 22 patients recorded normal impedance plethysmograms. Impedance plethysmography thus provided a non-invasive modality for confirmation of vascular compression in thoracic outlet syndrome.

  15. 21 CFR 870.2710 - Ear oximeter. (United States)


    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Ear oximeter. 870.2710 Section 870.2710 Food and... CARDIOVASCULAR DEVICES Cardiovascular Monitoring Devices § 870.2710 Ear oximeter. (a) Identification. An ear... ear. The amount of reflected or scattered light as indicated by this device is used to measure...

  16. Pulse oximetry in severe anaemia

    DEFF Research Database (Denmark)

    Ramsing, T; Rosenberg, J


    Measurement of arterial oxygen saturation by pulse oximetry was performed in two patients with acute and chronic anaemia (haemoglobin concentrations: 2.9 mmol/l (4.7 g/dl) and 1.9 mmol/l (3.0 g/dl), respectively) using a Radiometer OXI and a Nellcor N-200 pulse oximeter. The two oximeters read...... alternating different values in the two patients. In conclusion, pulse oximeters are able to give a value for oxygen saturation even at extreme anaemia, and when a high value is given, it possibly reflects arterial oxygen saturation. The value of pulse oximetry in severe anaemia is discussed....

  17. 21 CFR 870.2780 - Hydraulic, pneumatic, or photoelectric plethysmographs. (United States)


    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Hydraulic, pneumatic, or photoelectric... § 870.2780 Hydraulic, pneumatic, or photoelectric plethysmographs. (a) Identification. A hydraulic... using hydraulic, pneumatic, or photoelectric measurement techniques. (b) Classification. Class...

  18. Advanced Pulse Oximetry System for Remote Monitoring and Management

    Directory of Open Access Journals (Sweden)

    Ju Geon Pak


    Full Text Available Pulse oximetry data such as saturation of peripheral oxygen (SpO2 and pulse rate are vital signals for early diagnosis of heart disease. Therefore, various pulse oximeters have been developed continuously. However, some of the existing pulse oximeters are not equipped with communication capabilities, and consequently, the continuous monitoring of patient health is restricted. Moreover, even though certain oximeters have been built as network models, they focus on exchanging only pulse oximetry data, and they do not provide sufficient device management functions. In this paper, we propose an advanced pulse oximetry system for remote monitoring and management. The system consists of a networked pulse oximeter and a personal monitoring server. The proposed pulse oximeter measures a patient’s pulse oximetry data and transmits the data to the personal monitoring server. The personal monitoring server then analyzes the received data and displays the results to the patient. Furthermore, for device management purposes, operational errors that occur in the pulse oximeter are reported to the personal monitoring server, and the system configurations of the pulse oximeter, such as thresholds and measurement targets, are modified by the server. We verify that the proposed pulse oximetry system operates efficiently and that it is appropriate for monitoring and managing a pulse oximeter in real time.

  19. 21 CFR 870.1230 - Fiberoptic oximeter catheter. (United States)


    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Fiberoptic oximeter catheter. 870.1230 Section 870...) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Diagnostic Devices § 870.1230 Fiberoptic oximeter catheter. (a) Identification. A fiberoptic oximeter catheter is a device used to estimate the...

  20. 指脉氧监测协助下提高桡动脉穿刺成功率并减少并发症%Improve the success rate of radial artery puncture and reduce complications with the help of the pulse oximeter

    Institute of Scientific and Technical Information of China (English)

    邵振鸿; 冀琳琳; 金慧燕


    目的:探讨指脉氧监测协助下是否可以提高桡动脉穿刺成功率并减少并发症。方法选取2012年7月至2013年3月桡动脉径路行冠脉介入诊治Allen试验阳性患者96例,Allen试验的同时给予指脉氧监测,记录Allen试验开始前、阳性结果判断时患者指脉氧饱和度分数变化,同时记录Allen试验结束后指脉氧饱和度分数恢复时间、穿刺成功率、穿刺时间、压迫时间以及穿刺血管并发症。结果指脉氧饱和度分数在Allen试验前和阳性结果判断时差异无统计学意义(P>0.05);指脉氧饱和度分数下降分数和恢复时间差异无统计学意义(P>0.05);各组穿刺成功率、穿刺时间、压迫时间和并发症差异无统计学意义(P>0.05)。结论虽然未观测到各项指标的统计学差异,但指脉氧监测可以更加直观的观测到患者的桡动脉和尺动脉侧支血供的通畅情况,提高桡动脉的穿刺成功率并减少并发症。%Objective To explore if the pulse oximeter can help improve the success rate of radial artery puncture and reduce complications.Methods Allen test was positive in 96 patients from July 2012 to March 2013, give pulse oximeter and then record the oxygen saturation saturation before the Allen test; after the Allen test, then record the oxygen saturation saturation, the recovery time, the success rate of puncture, puncture time, oppression time, and complications.Results The pulse oxygen saturation before and afterthe Allen test was not significantly different(P>0.05); the decreased scores and recovery time of oxygen saturation saturation was not significantly different(P>0.05); no significant differences was found in success rate of puncture, puncture time, oppression time, and complications(P>0.05).Conclusion pulse oximeter can be a more intuitive observation to the collateral blood supply of radial artery and ulnar artery, it also improve the success rate of radial artery

  1. Optimal filter bandwidth for pulse oximetry (United States)

    Stuban, Norbert; Niwayama, Masatsugu


    Pulse oximeters contain one or more signal filtering stages between the photodiode and microcontroller. These filters are responsible for removing the noise while retaining the useful frequency components of the signal, thus improving the signal-to-noise ratio. The corner frequencies of these filters affect not only the noise level, but also the shape of the pulse signal. Narrow filter bandwidth effectively suppresses the noise; however, at the same time, it distorts the useful signal components by decreasing the harmonic content. In this paper, we investigated the influence of the filter bandwidth on the accuracy of pulse oximeters. We used a pulse oximeter tester device to produce stable, repetitive pulse waves with digitally adjustable R ratio and heart rate. We built a pulse oximeter and attached it to the tester device. The pulse oximeter digitized the current of its photodiode directly, without any analog signal conditioning. We varied the corner frequency of the low-pass filter in the pulse oximeter in the range of 0.66-15 Hz by software. For the tester device, the R ratio was set to R = 1.00, and the R ratio deviation measured by the pulse oximeter was monitored as a function of the corner frequency of the low-pass filter. The results revealed that lowering the corner frequency of the low-pass filter did not decrease the accuracy of the oxygen level measurements. The lowest possible value of the corner frequency of the low-pass filter is the fundamental frequency of the pulse signal. We concluded that the harmonics of the pulse signal do not contribute to the accuracy of pulse oximetry. The results achieved by the pulse oximeter tester were verified by human experiments, performed on five healthy subjects. The results of the human measurements confirmed that filtering out the harmonics of the pulse signal does not degrade the accuracy of pulse oximetry.

  2. New hybrid reflectance optical pulse oximetry sensor for lower oxygen saturation measurement and for broader clinical application (United States)

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


    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.

  3. The accuracy and response characteristics of a simplified ear oximeter. (United States)

    Chapman, K R; D'Urzo, A; Rebuck, A S


    We evaluated the accuracy and speed of response of a newly available, lightweight, and relatively inexpensive ear oximeter (Biox II oximeter). The instrument was compared with another oximeter (Hewlett-Packard 47201A) under conditions of both steadily maintained and progressively increasing hypoxia induced in normal subjects by rebreathing. The new oximeter (Biox II), which can be operated in either a "normal" or "fast" response mode, as selected by a switch on the front panel, was evaluated in its "normal" mode during steady-state hypoxic conditions and in both "normal" and "fast" modes during progressive hypoxic conditions. The other oximeter (HP 47201A) was operated in its factory preset "normal" mode for all measurements. During steady-state hypoxia the relationship between oximetric arterial oxygen saturation (SaO2) readings (y) and spectrophotometrically measured SaO2 in samples of arterial blood (x) when SaO2 exceeded 65 percent was as follows: for the new oximeter (Biox), y = 0.95x + 3.25 (r = 0.96); and for the other oximeter (HP 47201A), y = 1.03x - 2.31 (r = 0.94). Neither of these relationships differed significantly from the line of identity. During trials of progressive isocapnic hypoxia induced acutely in ten normal subjects, SaO2 was measured continuously by both oximeters. With the new oximeter (Biox) operated in the "normal" mode, the relationship between values for SaO2 from it (y) and the other oximeter (Hewlett-Packard) (x) was y = 0.85x + 12.91 (r = 0.93). When the new oximeter (Biox) was switched to its "fast" response mode, the relationship more closely approximated the line of identity such that y = 1.05x - 5.95 (r = 0.98). The response of the new oximeter (Biox II) to an in vitro step change in saturation followed a complex nonexponential function characterized by small initial changes in output signal with the greatest changes in output occurring during the latter portion of the response period. The 50 percent response times of the new

  4. Evaluation of cardiac modulation in children in response to apnea/hypopnea using the Phone Oximeter(™). (United States)

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


    Individuals with sleep disordered breathing (SDB) can experience changes in automatic cardiac regulation as a result of frequent sleep fragmentation and disturbance in normal respiration and oxygenation that accompany most apnea/hypopnea events. In adults, these changes are reflected in enhanced sympathetic and reduced parasympathetic activity. In this study, we examined the autonomic cardiac regulation in children with and without SDB, through spectral and detrended fluctuation analysis (DFA) of pulse rate variability (PRV). PRV was measured from pulse-to-pulse intervals (PPIs) of the photoplethysmogram (PPG) recorded from 160 children using the Phone Oximeter(™) in the standard setting of overnight polysomnography. Spectral analysis of PRV showed the cardiac parasympathetic index (high frequency, HF) was lower (p Oximeter(™) could be the basis for a new screening tool for assessing PRV in non-clinical environment.

  5. Wearable wireless cerebral oximeter (Conference Presentation) (United States)

    Zhang, Xin; Jiang, Tianzi


    Cerebral oximeters measure continuous cerebral oxygen saturation using near-infrared spectroscopy (NIRS) technology noninvasively. It has been involved into operating room setting to monitor oxygenation within patient's brain when surgeons are concerned that a patient's levels might drop. Recently, cerebral oxygen saturation has also been related with chronic cerebral vascular insufficiency (CCVI). Patients with CCVI would be benefited if there would be a wearable system to measure their cerebral oxygen saturation in need. However, there has yet to be a wearable wireless cerebral oximeter to measure the saturation in 24 hours. So we proposed to develop the wearable wireless cerebral oximeter. The mechanism of the system follows the NIRS technology. Emitted light at wavelengths of 740nm and 860nm are sent from the light source penetrating the skull and cerebrum, and the light detector(s) receives the light not absorbed during the light pathway through the skull and cerebrum. The amount of oxygen absorbed within the brain is the difference between the amount of light sent out and received by the probe, which can be used to calculate the percentage of oxygen saturation. In the system, it has one source and four detectors. The source, located in the middle of forehead, can emit two near infrared light, 740nm and 860nm. Two detectors are arranged in one side in 2 centimeters and 3 centimeters from the source. Their measurements are used to calculate the saturation in the cerebral cortex. The system has included the rechargeable lithium battery and Bluetooth smart wireless micro-computer unit.


    Directory of Open Access Journals (Sweden)

    Ali N. Hamoodi


    Full Text Available In this work the measurement and displays of blood oxygen saturation and pulse rate are investigated practically using computer.The analysis involves the variation in blood oxygen saturation ratio and pulse rate. The results obtained are compared with kontron pulse oximeter 7840 device. The value obtained for the same person pulse rate is approximately equal to that obtained by the konton pulse oximeter 7840 device. The sensor used in this work is the finger clip.The advantages of using computer over kontron pulse oximeter 7840 device is that the data of the patient can be saved in the computer for many years and also it can be display at any time so that the doctor get file contains all data for each patient. 

  7. Plethysmographic measurements of specific airway resistance in young children

    DEFF Research Database (Denmark)

    Bisgaard, Hans; Nielsen, Kim G


    children. This article reviews the method, and proposes a protocol and criteria for quality assurance for assessment of sRaw in preschool children from 2 years of age. sRaw measurements offers a method for clinical monitoring and research during this critical period of growth and development early in life.......Validated methods for lung function measurements in young children are lacking. Plethysmographic measurement of specific airway resistance (sRaw) provides such a method applicable from 2 years of age. sRaw gauges airway resistance from the measurements of the pressure changes driving the airflow...... also been documented by this technique, and sRaw has recently been used in longitudinal studies of young children with chronic pulmonary diseases. Future developments should provide improved algorithms for thermal correction of the respired volumes and adapt the equipment to the special needs of young...

  8. Adjustable fetal phantom for pulse oximetry (United States)

    Stubán, Norbert; Niwayama, Masatsugu


    As the measuring head of a fetal pulse oximeter must be attached to the head of the fetus inside the mother's uterus during labor, testing, and developing of fetal pulse oximeters in real environment have several difficulties. A fetal phantom could enable evaluation of pulse oximeters in a simulated environment without the restrictions and difficultness of medical experiments in the labor room. Based on anatomic data we developed an adjustable fetal head phantom with three different tissue layers and artificial arteries. The phantom consisted of two arteries with an inner diameter of 0.2 and 0.4 mm. An electronically controlled pump produced pulse waves in the arteries. With the phantom we investigated the sensitivity of a custom-designed wireless pulse oximeter at different pulsation intensity and artery diameters. The results showed that the oximeter was capable of identifying 4% and 2% changes in diameter between the diastolic and systolic point in arteries of over 0.2 and 0.4 mm inner diameter, respectively. As the structure of the phantom is based on reported anatomic values, the results predict that the investigated custom-designed wireless pulse oximeter has sufficient sensitivity to detect the pulse waves and to calculate the R rate on the fetal head.

  9. [Evaluation of cerebral oxygenation in newborns with prematurity apnea: new frequency domain NIR oximeter]. (United States)

    Pratesi, S; Donzelli, G


    Near infrared spectroscopy (NIRS) is a non invasive, portable, safe technique for monitoring cerebral oxygenation and haemodynamics. A new frequency-domain tissue oximeter based on a multi-distance measurement protocol is presented. The effects of apneic episodes on cerebral and peripheral arterial oxygen saturation (SatO2) in preterm newborns, as monitored by NIRS and by pulse oximetry, are reported. The study population consist of 5 preterms (26 to 30 weeks of gestational age), in the second week of postnatal age, affected by apnea of prematurity. NIRS and pulse oximetric measurements were made contemporarily for a 40-minutes period for each infant. All monitorized apneic events were associated with bradicardia, and resolved spontaneously or after tactile stimulation. As results: a) there was always cerebral deoxygenation in association with apneic events, b) the mean SatO2 as measured by NIRS was slightly lower than the pulse oximeter readings, c) cerebral SatO2 decreased faster and the absolute value of the cerebral SaO2 decrease was greater than that measured peripherally (mean value of 27 versus 13%), d) increases of cerebral deoxyhemoglobin and total hemoglobin and a decrease of oxyhemoglobin were also observed. These preliminary results show that peripheral oxygen saturation measurements as measured by pulse oximetry could not always reflect brain oxygenation.

  10. A Novel Ring Shaped Photodiode for Reflectance Pulse Oximetry in Wireless Applications

    DEFF Research Database (Denmark)

    Duun, Sune; Haahr, Rasmus Grønbek; Birkelund, Karen;


    We present a pulse oximeter for use in home-care applications in a sticking patch with integrated electronics. The core in the pulse oximeter is a large ring shaped backside silicon pn photodiode placed around a Ledtronics dual LED with wavelengths of 660 nm and 940 nm. The concentric photodiode...

  11. A Piezoelectric Plethysmograph Sensor Based on a Pt Wire Implanted Lead Lanthanum Zirconate Titanate Bulk Ceramic

    Directory of Open Access Journals (Sweden)

    Ernesto Suaste-Gómez


    Full Text Available This work reports on the development of a Lead Lanthanum Zirconate Titanate (PLZT bulk ferroelectric poled ceramic structure as a Piezoelectric Plethysmograph (PZPG sensor. The ceramic was implanted during its fabrication with a platinum (Pt wire which works as an internal electrode. The ceramic was then submitted to an experimental setup in order to validate and determine the Pt-wire mechanical effects. This PZPG sensor was also mounted on a finger splint in order to measure the blood flow that results from the pulsations of blood occurring with each heartbeat. Fingertip pulses were recorded jointly with an ECG signal from a 25 year old male to compare the time shift; the PZPG sensor guarantees the electrical isolation of the patient. The proposed PZPG has several advantages: it can be adjusted for fingertip measurements, but it can easily be extended by means of spare bands, therefore making possible PZPG measurements from different body locations, e.g., forehead, forearm, knee, neck, etc.

  12. Algorithms that eliminate the effects of calibration artefact and trial-imposed offsets of Masimo oximeter in BOOST-NZ trial. (United States)

    Zahari, Marina; Lee, Dominic Savio; Darlow, Brian Alexander


    The displayed readings of Masimo pulse oximeters used in the Benefits Of Oxygen Saturation Targeting (BOOST) II and related trials in very preterm babies were influenced by trial-imposed offsets and an artefact in the calibration software. A study was undertaken to implement new algorithms that eliminate the effects of offsets and artefact. In the BOOST-New Zealand trial, oxygen saturations were averaged and stored every 10 s up to 36 weeks' post-menstrual age. Two-hundred and fifty-seven of 340 babies enrolled in the trial had at least two weeks of stored data. Oxygen saturation distribution patterns corresponding with a +3 % or -3 % offset in the 85-95 % range were identified together with that due to the calibration artefact. Algorithms involving linear and quadratic interpolations were developed, implemented on each baby of the dataset and validated using the data of a UK preterm baby, as recorded from Masimo oximeters with the original software and a non-offset Siemens oximeter. Saturation distributions obtained were compared for both groups. There were a flat region at saturations 85-87 % and a peak at 96 % from the lower saturation target oximeters, and at 93-95 and 84 % respectively from the higher saturation target oximeters. The algorithms lowered the peaks and redistributed the accumulated frequencies to the flat regions and artefact at 87-90 %. The resulting distributions were very close to those obtained from the Siemens oximeter. The artefact and offsets of the Masimo oximeter's software had been addressed to determine the true saturation readings through the use of novel algorithms. The implementation would enable New Zealand data be included in the meta-analysis of BOOST II trials, and be used in neonatal oxygen studies.

  13. A Clinical Tissue Oximeter Using NIR Time-Resolved Spectroscopy. (United States)

    Fujisaka, Shin-ichi; Ozaki, Takeo; Suzuki, Tsuyoshi; Kamada, Tsuyoshi; Kitazawa, Ken; Nishizawa, Mitsunori; Takahashi, Akira; Suzuki, Susumu


    The tNIRS-1, a new clinical tissue oximeter using NIR time-resolved spectroscopy (TRS), has been developed. The tNIRS-1 measures oxygenated, deoxygenated and total hemoglobin and oxygen saturation in living tissues. Two-channel TRS measurements are obtained using pulsed laser diodes (LD) at three wavelengths, multi-pixel photon counters (MPPC) for light detection, and time-to-digital converters (TDC) for time-of-flight photon measurements. Incorporating advanced semiconductor devices helped to make the design of this small-size, low-cost and low-power TRS instrument possible. In order to evaluate the correctness and reproducibility of measurement data obtained with the tNIRS-1, a study using blood phantoms and healthy volunteers was conducted to compare data obtained from a conventional SRS device and data from an earlier TRS system designed for research purposes. The results of the study confirmed the correctness and reproducibility of measurement data obtained with the tNIRS-1. Clinical evaluations conducted in several hospitals demonstrated a high level of usability in clinical situations and confirmed the efficacy of measurement data obtained with the tNIRS-1.

  14. A multichannel time-domain brain oximeter for clinical studies (United States)

    Contini, Davide; Spinelli, Lorenzo; Caffini, Matteo; Cubeddu, Rinaldo; Torricelli, Alessandro


    We developed and optimized a multichannel dual-wavelength time-domain brain oximeter for functional studies in the clinical environment. The system, mounted on a 19"-rack, is interfaced with instrumentation for monitoring physiological parameters and for stimuli presentation.

  15. Distant Measurement of Plethysmographic Signal in Various Lighting Conditions Using Configurable Frame-Rate Camera

    Directory of Open Access Journals (Sweden)

    Przybyło Jaromir


    Full Text Available Videoplethysmography is currently recognized as a promising noninvasive heart rate measurement method advantageous for ubiquitous monitoring of humans in natural living conditions. Although the method is considered for application in several areas including telemedicine, sports and assisted living, its dependence on lighting conditions and camera performance is still not investigated enough. In this paper we report on research of various image acquisition aspects including the lighting spectrum, frame rate and compression. In the experimental part, we recorded five video sequences in various lighting conditions (fluorescent artificial light, dim daylight, infrared light, incandescent light bulb using a programmable frame rate camera and a pulse oximeter as the reference. For a video sequence-based heart rate measurement we implemented a pulse detection algorithm based on the power spectral density, estimated using Welch’s technique. The results showed that lighting conditions and selected video camera settings including compression and the sampling frequency influence the heart rate detection accuracy. The average heart rate error also varies from 0.35 beats per minute (bpm for fluorescent light to 6.6 bpm for dim daylight.

  16. Perfusion index and plethysmographic variability index in patients with interscalene nerve catheters. (United States)

    Sebastiani, Anne; Philippi, Larissa; Boehme, Stefan; Closhen, Dorothea; Schmidtmann, Irene; Scherhag, Anton; Markstaller, Klaus; Engelhard, Kristin; Pestel, Gunther


    Interscalene nerve blocks provide adequate analgesia, but there are no objective criteria for early assessment of correct catheter placement. In the present study, pulse oximetry technology was used to evaluate changes in the perfusion index (PI) in both blocked and unblocked arms, and changes in the plethysmographic variability index (PVI) were evaluated once mechanical ventilation was instituted. The PI and PVI values were assessed using a Radical-7™ finger pulse oximetry device (Masimo Corp., Irvine, CA, USA) in both arms of 30 orthopedic patients who received an interscalene catheter at least 25 min before induction of general anesthesia. Data were evaluated at baseline, on application of local anesthetics; five, ten, and 15 min after onset of interscalene nerve blocks; after induction of general anesthesia; before and after a 500 mL colloid fluid challenge; and five minutes thereafter. In the 25 patients with successful blocks, the difference between the PI values in the blocked arm and the PI values in the contralateral arm increased within five minutes of the application of the local anesthetics (P < 0.05) and increased progressively until 15 min. After induction of general anesthesia, the PI increased in the unblocked arm while it remained relatively constant in the blocked arm, thus reducing the difference in the PI. A fluid challenge resulted in a decrease in PVI values in both arms. The perfusion index increases after successful interscalene nerve blockade and may be used as an indicator for successful block placement in awake patients. The PVI values before and after a fluid challenge can be useful to detect changes in preload, and this can be performed in both blocked and unblocked arms.

  17. Development and Uses of an Eye Oximeter (United States)

    Hillman, Lloyd W.; Smith, Matthew H.; Denninghoff, Kurt


    The eye provides an unique porthole into the physiology of the body. Over the past seven years researchers at The University of Alabama in Huntsville (UAH) and The University of Alabama at Birmingham (UAB) have been developing a new technique for noninvasively measuring oxygen saturation. The program's main thrust is to address the basic scientific and bioengineering issues of a new biomedical instrument—an eye oximeter (EOX). An EOX shines low-power laser light into a subject's eye and scans the beams across the arteries and veins of the retina. The light scattered back out of the eye is collected and analyzed. Performing this measurement at multiple wavelengths allows the oxygen saturation of blood in retinal vessels to be analyzed. Noninvasive optical measurement in the eye offers a new procedure for low-cost diagnosis and treatment. For example, the EOX provides a fast, simple and noninvasive means of detecting early blood loss in trauma victims. The measurement is fast, noninvasive, and presents minimal risk to the patient compared to established techniques that are invasive, high-risk, and expensive. This talk will give an overview and describe the basic scientific and bioengineering issues of the retinal scanning technique used in the EOX and the medical applications and clinical goals.

  18. Impact of study oximeter masking algorithm on titration of oxygen therapy in the Canadian oxygen trial. (United States)

    Schmidt, Barbara; Roberts, Robin S; Whyte, Robin K; Asztalos, Elizabeth V; Poets, Christian; Rabi, Yacov; Solimano, Alfonso; Nelson, Harvey


    To compare oxygen saturations as displayed to caregivers on offset pulse oximeters in the 2 groups of the Canadian Oxygen Trial. In 5 double-blind randomized trials of oxygen saturation targeting, displayed saturations between 88% and 92% were offset by 3% above or below the true values but returned to true values below 84% and above 96%. During the transition, displayed values remained static at 96% in the lower and at 84% in the higher target group during a 3% change in true saturations. In contrast, displayed values changed rapidly from 88% to 84% in the lower and from 92% to 96% in the higher target group during a 1% change in true saturations. We plotted the distributions of median displayed saturations on days with >12 hours of supplemental oxygen in 1075 Canadian Oxygen Trial participants to reconstruct what caregivers observed at the bedside. The oximeter masking algorithm was associated with an increase in both stability and instability of displayed saturations that occurred during the transition between offset and true displayed values at opposite ends of the 2 target ranges. Caregivers maintained saturations at lower displayed values in the higher than in the lower target group. This differential management reduced the separation between the median true saturations in the 2 groups by approximately 3.5%. The design of the oximeter masking algorithm may have contributed to the smaller-than-expected separation between true saturations in the 2 study groups of recent saturation targeting trials in extremely preterm infants. Copyright © 2014 Elsevier Inc. All rights reserved.

  19. Cephalic versus digital plethysmographic variability index measurement: a comparative pilot study in cardiac surgery patients. (United States)

    Fischer, Marc-Olivier; Pellissier, Arnaud; Saplacan, Vladimir; Gérard, Jean-Louis; Hanouz, Jean-Luc; Fellahi, Jean-Luc


    Noninvasive measurement of digital plethysmographic variability index (PVI(digital)) has been proposed to predict fluid responsiveness, with conflicting results. The authors tested the hypothesis that cephalic sites of PVI measurement (namely PVI(ear) and PVI(forehead)) could be more discriminant than PVI(digital) to predict fluid responsiveness after cardiac surgery. A prospective observational study. A cardiac surgical intensive care unit of a university hospital. Fifty adult patients. Investigation before and after fluid challenge. Patients were prospectively included within the first 6-hour postoperative period and investigated before and after fluid challenge. A positive response to fluid challenge was defined as a 15% increase in cardiac index. PVI(digital), PVI(ear), PVI(forehead), and invasive arterial pulse-pressure variation (PPV) measurements were recorded simultaneously, and receiver operating characteristic (ROC) curves were built. Forty-one (82%) patients were responders and 9 (18%) patients were nonresponders to fluid challenge. ROCAUC were 0.74 (95% confidence interval [95% CI]: 0.60-0.86), 0.81 (95% CI: 0.68-0.91), 0.88 (95% CI: 0.75-0.95) and 0.87 (95% CI: 0.75-0.95) for PVI(digital), PVI(ear), PVI(forehead), and PPV, respectively. Significant differences were observed between PVI(forehead) and PVI(digital) (absolute difference in ROCAUC = 0.134 [95% CI: 0.003-0.265], p = 0.045) and between PPV and PVI(digital) (absolute difference in ROCAUC = 0.129 [95% CI: 0.011-0.247], p = 0.033). The percentage of patients within the inconclusive class of response was 46%, 70%, 44%, and 26% for PVI(digital), PVI(ear), PVI(forehead), and PPV, respectively. PVI(forehead) was more discriminant than PVI(digital) and could be a valuable alternative to arterial PPV in predicting fluid responsiveness. Copyright © 2014 Elsevier Inc. All rights reserved.


    NARCIS (Netherlands)



    Transmission pulse oximetry is used for monitoring in many clinical settings. However, for fetal monitoring during labor and in situations with poor peripheral perfusion, transmission pulse oximetry cannot be used. Therefore, we developed a reflectance pulse oximeter, which uses the relative intensi

  1. Quantitative evaluation of ViOptix's tissue oximeter in an ex-vivo animal model (United States)

    Mao, Jimmy J. M.; Xu, Ronald; Lash, Bob; Wright, Leigh


    We evaluate the performance of ODISsey TM Tissue Oximeter (ViOptix, Inc., Fremont, CA) against co-oximeter. Concurrent oxygen saturation measurements were made in three dog limbs surgically removed and perfused with an extracorporeal blood circulation system. Oxygen saturation was adjusted in steps ranging from 95% down to 5% as monitored by the co-oximeter. The co-oximeter was used to measure the oxygen saturation of the whole blood drawn from both the arterial and the venous ports of the limb. The tissue oxygenation measured by the ODISsey TM tissue oximeter was compared with the average of the arterial and the venous blood oxygenation measured by the co-oximeter. Linear correlation was observed between the average oxygenation given by the co-oximeter and the ODISseyTM readings, with a root-mean-square difference of 7.6% and the correlation coefficient of 0.941, calculated from N = 194 data points.

  2. Validation of pulse oximetry for monitoring of hypoxaemic episodes in the late postoperative period

    DEFF Research Database (Denmark)

    Stausholm, K; Rosenberg-Adamsen, S; Edvardsen, L;


    We monitored 12 patients undergoing major abdominal surgery using a pulse oximeter (Nellcor N-200) and a transcutaneous oxygen tension monitor (TINA, Radiometer A/S) on the second or third night after operation. Of the shortest hypoxaemic episodes measured with the pulse oximeter (... duration), 78% also occurred in the transcutaneous oxygen tension measurement. Episodes of longer duration (> or = 1 min duration on the pulse oximeter) were, in 95% of cases, reflected in the transcutaneous oxygen tension measurement also. Thus postoperative episodic desaturations lasting > or = 1 min...

  3. The Effect of Skin Pigmentation on the Accuracy of Pulse Oximetry in Infants with Hypoxemia. (United States)

    Foglia, Elizabeth E; Whyte, Robin K; Chaudhary, Aasma; Mott, Antonio; Chen, Jodi; Propert, Kathleen J; Schmidt, Barbara


    To compare pulse oximetry measurement bias between infants with hypoxemia with either dark skin or light skin with Masimo Radical 7 and Nellcor Oximax. There was no significant difference in systematic bias based on skin pigment for either oximeter.

  4. A comparison of limb plethysmograph systems proposed for use on the Space Shuttle (United States)

    Levitan, B. M.; Montgomery, L. D.; Bhagat, P. K.; Zieglschmid, J. F.


    Comparisons of a Whitney mercury-filled double-stranded strain gauge with two plethysmographs proposed for Shuttle use - an ultrasound and an impedance plethysmograph - were performed on 20 subjects. An occlusive thigh pressure cuff, inflated to 50 mm Hg, caused partial venous occlusion and subsequent blood pooling distal to the cuff. The average maximum volume changes observed in the Whitney/ultrasound test were 2.07% and 3.35%, respectively, and 2.12% and 2.53% for the Whitney/Impedance comparison. Applying the ratio of the maximum volume changes to the gain of each test system caused the impedance and ultrasound volume change determinations to be essentially identical to the Whitney gauge. The three different limb parameters measured result in significant magnitude differences but the three systems track their respective changes identically.

  5. Pulse (United States)

    ... resting for at least 10 minutes. Take the exercise heart rate while you are exercising. ... pulse rate can help determine if the person's heart is pumping. Pulse ... rate gives information about your fitness level and health.

  6. Singing Greeting Card Beeper as a Finger Pulse Sensor (United States)

    Belusic, Gregor; Zupancic, Gregor


    We constructed a robust and low-priced finger pulse sensor from a singing greeting card beeper. The beeper outputs the plethysmographic signal, which is indistinguishable from that of commercial grade sensors. The sensor can be used in school for a number of experiments in human cardiovascular physiology.

  7. Singing Greeting Card Beeper as a Finger Pulse Sensor (United States)

    Belusic, Gregor; Zupancic, Gregor


    We constructed a robust and low-priced finger pulse sensor from a singing greeting card beeper. The beeper outputs the plethysmographic signal, which is indistinguishable from that of commercial grade sensors. The sensor can be used in school for a number of experiments in human cardiovascular physiology.

  8. Clinical evaluation of pulse oximetry monitors on critically ill patients. (United States)

    De Pauw, C; Poelaert, J; Rolly, G; Colardyn, F


    Four pulse oximeters and two pulse oximeter-capnographs were evaluated on accuracy of measuring oxygen saturation and heartrate for the former and oxygen saturation, heartrate, respiratory rate and capnography for the latter. In the first part of the study four pulse oximeters (Criticare Systems Model 501 +, Ohmeda Biox 3700 Pulse Oximeter, Nellcor Model N 100 and Datex Satlite) were simultaneously studied on 10 ventilated ICU patients. Fifty simultaneous measurements were done for heartrate and oxygen saturation and compared to arterial saturations and ECG heartrates. Mean differences from pulse oximeter values versus control arterial and ECG values were within two percent for the four instruments. In the second part two oxicaps (Ohmeda 4700 and Nellcor N 1000) were evaluated with the same control parameters. Thirty measurements on 3 patients were done. As in the first part of the study all results were accurate within two percent of control values. From those data we can conclude that all examined monitors were fairly accurate compared to simultaneous arterial blood gas analysis and ECG monitoring. The oxicap monitors have the advantage of giving continuous information on two very important parameters of patient monitoring: CO2 and saturation.

  9. Retinal oximeter for the blue-green oximetry technique (United States)

    Denninghoff, Kurt R.; Sieluzycka, Katarzyna B.; Hendryx, Jennifer K.; Ririe, Tyson J.; Deluca, Lawrence; Chipman, Russell A.


    Retinal oximetry offers potential for noninvasive assessment of central venous oxyhemoglobin saturation (SO2) via the retinal vessels but requires a calibrated accuracy of +/-3% saturation in order to be clinically useful. Prior oximeter designs have been hampered by poor saturation calibration accuracy. We demonstrate that the blue-green oximetry (BGO) technique can provide accuracy within +/-3% in swine when multiply scattered light from blood within a retinal vessel is isolated. A noninvasive on-axis scanning retinal oximeter (ROx-3) is constructed that generates a multiwavelength image in the range required for BGO. A field stop in the detection pathway is used in conjunction with an anticonfocal bisecting wire to remove specular vessel reflections and isolate multiply backscattered light from the blood column within a retinal vessel. This design is tested on an enucleated swine eye vessel and a retinal vein in a human volunteer with retinal SO2 measurements of ~1 and ~65%, respectively. These saturations, calculated using the calibration line from earlier work, are internally consistent with a standard error of the mean of +/-2% SO2. The absolute measures are well within the expected saturation range for the site (-1 and 63%). This is the first demonstration of noninvasive on-axis BGO retinal oximetry.

  10. Hematoma of the proximal nail fold due to oximeter in a child

    Directory of Open Access Journals (Sweden)

    Patricia Chang


    Full Text Available Boy 4 years old, hospitalized due to hemorrhagic chickenpox and sepsis during his clinical examination besides hemorrhagic crust, vesicles and bullous he has also a cutaneous red lesion localized at the right proximal nail fold of the big toenail (Fig. 1, dermatoscopic view of the lesion (Fig. 2. The diagnosis of hematoma of the proximal nail fold due to oximeter was done. The proximal nail fold hematomas due to oximeter are uncommon dermatoses at this level that are caused for the pressure of the oximeter and it has been seeing in patient in Unit Intensive or Intermediate Unit Care since 2007.

  11. Accuracy of two ear oximeters at rest and during exercise in pulmonary patients. (United States)

    Ries, A L; Farrow, J T; Clausen, J L


    The accuracy of 2 ear oximeters (Hewlett-Packard 47201A and Biox IIA) was evaluated at rest and during exercise in 116 pulmonary patients. Ear oximetry measurements were compared with arterial oxygen saturation (SaO2) measured from simultaneous arterial blood samples. When used according to the manufacturer's instructions for stabilization during exercise testing, both oximeters demonstrated comparable accuracy in estimating arterial blood SaO2 both at rest and during exercise in these patients (95% confidence limits, 2 SEE = +/- 4 to 5%). The oximeters were more accurate in measuring a change in SaO2 from a previous reading (95% confidence limits, 2 SEE = +/- 2.5 to 3.5%). COHgb levels greater than 4% and dark skin pigmentation appeared to decrease the accuracy of ear oximetry measurements. Within the limitations of accuracy, both ear oximeters may be useful for clinical exercise testing in pulmonary patients.

  12. A new air displacement plethysmograph for the determination of Japanese body composition. (United States)

    Miyatake, N; Nonaka, K; Fujii, M


    A new device based on the plethysmographic measurement of body volume, named the BOD POD Body Composition System, was developed for the purpose of estimating body composition. The performance, reliability, validity, and clinical application of this system were evaluated in Japanese subjects. The coefficient variation (CV:%) in same-day tests was 2.48, in three separate-day tests it was 2.27, and for independent operators it was 4.53, respectively. There was a clear correlation between the results from BOD POD and those from dual energy X-ray absorptiometry (DEXA) (r = 0.910, p BOD POD. The findings indicate that the BOD POD is a highly reliable and valid method for determining body fat percentage. This new method has several advantages, e.g. it is quick, simple to operate and may accommodate wide populations.

  13. Respiratory variations in the photoplethysmographic waveform amplitude depend on type of pulse oximetry device. (United States)

    Høiseth, Lars Øivind; Hoff, Ingrid Elise; Hagen, Ove Andreas; Kirkebøen, Knut Arvid; Landsverk, Svein Aslak


    Respiratory variations in the photoplethysmographic waveform amplitude predict fluid responsiveness under certain conditions. Processing of the photoplethysmographic signal may vary between different devices, and may affect respiratory amplitude variations calculated by the standard formula. The aim of the present analysis was to explore agreement between respiratory amplitude variations calculated using photoplethysmographic waveforms available from two different pulse oximeters. Analysis of registrations before and after fluid loads performed before and after open-heart surgery (aortic valve replacement and/or coronary artery bypass grafting) with patients on controlled mechanical ventilation. Photoplethysmographic (Nellcor and Masimo pulse oximeters) and arterial pressure waveforms were recorded. Amplitude variations induced by ventilation were calculated and averaged over ten respiratory cycles. Agreements for absolute values are presented in scatterplots (with least median square regression through the origin, LMSO) and Bland-Altman plots. Agreement for trending presented in a four-quadrant plot. Agreement between respiratory photoplethysmographic amplitude variations from the two pulse oximeters was poor with LMSO ΔPOPNellc = 1.5 × ΔPOPMas and bias ± limits of agreement 7.4 ± 23 %. Concordance rate with a fluid load was 91 %. Agreement between respiratory variations in the photoplethysmographic waveform amplitude calculated from the available signals output by two different pulse oximeters was poor, both evaluated by LMSO and Bland-Altman plot. Respiratory amplitude variations from the available signals output by these two pulse oximeters are not interchangeable.

  14. Physiological monitoring in firefighter ensembles: wearable plethysmographic sensor vest versus standard equipment. (United States)

    Coca, Aitor; Roberge, Raymond J; Williams, W Jon; Landsittel, Douglas P; Powell, Jeffrey B; Palmiero, Andrew


    We evaluated the accuracy of a wearable sensor vest for real-time monitoring of physiological responses to treadmill exercise. Ten subjects in standard firefighter ensembles, treadmill exercising at 50% VO(2) max, had heart rate (HR), respiratory rate (RR), skin temperature (T(sk)), oxygen saturation (SaO(2)), tidal volume (V(T)), and minute ventilation (V(E)) recorded concurrently by a wearable plethysmographic sensor vest and standard laboratory physiological monitoring equipment for comparison. A high degree of correlation was noted for most of the measured variables [HR (r = 0.99), RR (r = 0.98), T(sk) (r = 0.98), V(E) (r = 0.88), and SaO(2) (r = 0.79)]. V(T) (r = 0.60) had a moderate correlation, although a paired differences analysis showed a mean paired difference of -0.03 L. This mean paired difference represents a 1.92% variation for V(T). Data from the wearable sensor vest is comparable to data captured from standard laboratory physiological monitoring equipment on subjects wearing standard firefighter ensembles while exercising at a moderate work rate. This study demonstrates the accuracy of the wearable sensor technology for these physiological parameters under these conditions and suggests that it could be useful for actual field studies of firefighters in traditional firefighting gear.

  15. Calibration of a prototype NIRS oximeter against two commercial devices on a blood-lipid phantom

    DEFF Research Database (Denmark)

    Hyttel-Sorensen, Simon; Kleiser, Stefan; Wolf, Martin


    In a blood-lipid liquid phantom the prototype near-infrared spectroscopy oximeter OxyPrem was calibrated against the INVOS® 5100c adult sensor in respect to values of regional tissue oxygen haemoglobin saturation (rStO2) for possible inclusion in the randomised clinical trial - SafeBoosC. In addi......In a blood-lipid liquid phantom the prototype near-infrared spectroscopy oximeter OxyPrem was calibrated against the INVOS® 5100c adult sensor in respect to values of regional tissue oxygen haemoglobin saturation (rStO2) for possible inclusion in the randomised clinical trial - SafeBoos...

  16. Plethysmographic variability index (PVI) accuracy in predicting fluid responsiveness in anesthetized children. (United States)

    Julien, Florence; Hilly, Julie; Sallah, Tarik B; Skhiri, Alia; Michelet, Daphné; Brasher, Christopher; Varin, Laurent; Nivoche, Yves; Dahmani, Souhayl


    Plethysmographic Variability Index (PVI) has been shown to accurately predict responsiveness to fluid loads in adults. The goal of this study was to evaluate PVI accuracy when predicting fluid responsiveness during noncardiac surgery in children. Children aged 2-10 years scheduled for noncardiac surgery under general anesthesia were included. PVI was assessed concomitantly with stroke volume index (SVI). A response to fluid load was defined by an SVI increase of more than 15%. A 10 ml·kg(-1) normal saline intravenous fluid challenge was administered before surgical incision and after anesthetic induction. After incision, fluid challenges were administered when SVI values decreased by more than 15% or where judged necessary by the anesthesiologist. Statistical analyses include receiving operator characteristics (ROC) analysis and the determination of gray zone method with an error tolerance of 10%. Fifty-four patients were included, 97 fluid challenges administered and 45 responses recorded. Area under the curve of ROC curves was 0.85 [0.77-0.93] and 0.8 [0.7-0.89] for baseline PVI and SVI values, respectively. Corresponding gray zone limits were [10-17%] and [22-31 ml·m(-2)], respectively. PVI values exhibited different gray zone limits for pre-incision and postincision fluid challenges, whereas SVI values were comparable. PVI value percentages in the gray zone were 34% overall and 44% for challenges performed after surgical incision. This study found both PVI and prechallenge SVI to be accurate when used to predict fluid load response during anesthetized noncardiac surgery in children. However, a third of recorded PVI values were inconclusive. © 2013 Blackwell Publishing Ltd.

  17. Finger blood content, light transmission, and pulse oximetry errors. (United States)

    Craft, T M; Lawson, R A; Young, J D


    The changes in light emitting diode current necessary to maintain a constant level of light incident upon a photodetector were measured in 20 volunteers at the two wavelengths employed by pulse oximeters. Three states of finger blood content were assessed; exsanguinated, hyperaemic, and normal. The changes in light emitting diode current with changes in finger blood content were small and are not thought to represent a significant source of error in saturation as measured by pulse oximetry.

  18. Continuous pulse oximetry in the general surgical ward: Nellcor N-200 versus Nellcor N-3000

    DEFF Research Database (Denmark)

    Christensen, M; Lie, C; Rosenberg, J


    Symphony N-3000 with the Nellcor N-200 pulse oximeter, when monitoring patients in the general surgical ward. Twenty-two patients were monitored during unrestricted ward activities for a total of 275 h with a N-3000 and a N-200 pulse oximeter simultaneously. Data were analysed for lack of concordance...... between the two pulse oximeters with respect to frequency of registered hypoxaemic episodes and thus the amount of time spent in the alarm state. The median number of desaturation episodes with the N-200 was 18 (range 0-511) compared with four (range 0-476) with the N-3000 (p ... of drop-outs (loss of signal) was 13 (range 1-46) with the N-200 compared with nine (2-41) with the N-3000 (p = 0.06). The N-200 registered saturation values of 85% or below for 23% of the observation time compared with 6% of the observation time with the N-3000 pulse oximeter (p

  19. Notes on the apparent discordance of pulse oximetry and multi-wavelength haemoglobin photometry

    NARCIS (Netherlands)

    Nijland, R.; Jongsma, H.W.; Nijhuis, J.G.; Oeseburg, Berend; Zijlstra, Willem


    Multi-wavelength photometers, blood gas analysers and pulse oximeters are widely used to measure various oxygen-related quantities. The definitions of these quantities are not always correct. This paper gives insight in the various definitions for oxygen quantities. Furthermore, the possible

  20. Notes on the apparent discordance of pulse oximetry and multi-wavelength haemoglobin photometry

    NARCIS (Netherlands)

    Nijland, Rick; Jongsma, H.W.; Nijhuis, J.G.; Oeseburg, Berend; Zijlstra, Willem


    Multi-wavelength photometers, blood gas analysers and pulse oximeters are widely used to measure various oxygen-related quantities. The definitions of these quantities are not always correct. This paper gives insight in the various definitions for oxygen quantities. Furthermore, the possible influen

  1. The Choroidal Eye Oximeter - An instrument for measuring oxygen saturation of choroidal blood in vivo (United States)

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


    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.

  2. Carbon monoxide analysis: a comparison of two co-oximeters and headspace gas chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Costantino, A.G.; Park, J.; Caplan, Y.H.

    Three methods (lL-182 Co-Oximeter, lL-282 Co-Oximeter, and headspace gas chromatography) for the analysis of carbon monoxide in postmortem blood were studied and compared using a prepared reference standard, Quantra control materials, and 62 postmortem blood specimens. The methods compared favorably with one another. The linear regression equations for the 62 postmortem blood samples (range = 1.0 to 86% saturation) were: lL-282 vs. lL-182, y = 1.11x - 3.10, r = 0.981; lL-182 vs. GC, y = 0.88x + 2.97, r = 0.973; lL-282 vs. GC, y = 1.00x - 1.24, r = 0.986.

  3. Incorporating oximeter analyses to investigate synchronies in heart rate while teaching and learning about race (United States)

    Amat, Arnau; Zapata, Corinna; Alexakos, Konstantinos; Pride, Leah D.; Paylor-Smith, Christian; Hernandez, Matthew


    In this paper, we look closely at two events selected through event-oriented inquiry that were part of a classroom presentation on race. The first event was a provocative discussion about Mark Twain's ( Pudd'nhead Wilson, Harper, New York, 1899) and passing for being White. The other was a discussion on the use of the N-word. Grounded in authentic inquiry, we use ethnographic narrative, cogenerative dialogues, and video and oximeter data analyses as part of a multi-ontological approach for studying emotions. Statistical analysis of oximeter data shows statistically significant heart rate synchrony among two of the coteachers during their presentations, providing evidence of emotional synchrony, resonance, and social and emotional contagion.

  4. Processing of pulse oximeter signals using adaptive filtering and autocorrelation to isolate perfusion and oxygenation components (United States)

    Ibey, Bennett; Subramanian, Hariharan; Ericson, Nance; Xu, Weijian; Wilson, Mark; Cote, Gerard L.


    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.

  5. Monte Carlo modeling of spatially complex wrist tissue for the optimization of optical pulse oximeters (United States)

    Robinson, Mitchell; Butcher, Ryan; Coté, Gerard L.


    Monte Carlo modeling of photon propagation has been used in the examination of particular areas of the body to further enhance the understanding of light propagation through tissue. This work seeks to improve upon the established simulation methods through more accurate representations of the simulated tissues in the wrist as well as the characteristics of the light source. The Monte Carlo simulation program was developed using Matlab. Generation of different tissue domains, such as muscle, vasculature, and bone, was performed in Solidworks, where each domain was saved as a separate .stl file that was read into the program. The light source was altered to give considerations to both viewing angle of the simulated LED as well as the nominal diameter of the source. It is believed that the use of these more accurate models generates results that more closely match those seen in-vivo, and can be used to better guide the design of optical wrist-worn measurement devices.

  6. An analysis on the theory of pulse oximetry by Monte Carlo simulation (United States)

    Fan, Shangchun; Cai, Rui; Xing, Weiwei; Liu, Changting; Chen, Guangfei; Wang, Junfeng


    The pulse oximetry is a kind of electronic instrument that measures the oxygen saturation of arterial blood and pulse rate by non-invasive techniques. It enables prompt recognition of hypoxemia. In a conventional transmittance type pulse oximeter, the absorption of light by oxygenated and reduced hemoglobin is measured at two wavelength 660nm and 940nm. But the accuracy and measuring range of the pulse oximeter can not meet the requirement of clinical application. There are limitations in the theory of pulse oximetry, which is proved by Monte Carlo method. The mean paths are calculated in the Monte Carlo simulation. The results prove that the mean paths are not the same between the different wavelengths.

  7. Next-generation pulse oximetry. Focusing on Masimo's signal extraction technology. (United States)


    Pulse oximeters are used to determine trends in patients' blood oxygen saturation and to warn of dangerous saturation levels. But conventional pulse oximetry has some inherent limitations. For example, it has difficulty monitoring patients who are moving or who have poor perfusion; it is also subject to interference from certain visible and infrared light sources. Over the past several years, a number of companies have developed advanced signal-processing techniques that allow pulse oximeters to overcome many of these limitations. We refer to such new technologies as next-generation pulse oximetry. In this Evaluation, we focus on the first next-generation technology to have reached the market: Masimo Corporation's Signal Extraction Technology (SET). We designed our study of Masimo SET to address the main question that needs to be asked of any next-generation technology: How well does it compare to conventional pulse oximetry? Specifically, how well does it perform when a patient is moving or being moved, when a patient is poorly perfused, or when certain types of light strike the sensor while it is attached to or detached from the patient? We also examined one type of sensor used with this product, comparing it to conventional tape-on sensors for comfort and durability. Several other next-generation pulse-oximeter products have become available since we began this study. We are currently evaluating these products and will publish our findings in the near future. A list of the products, including a brief description of each, is included in this article. Pulse oximeters are used to determine trends in patients' blood oxygen saturation and to warn against dangerous saturation levels. These monitors are often vital in helping to ensure patient safety, especially for critically ill patients, pediatric patients, and neonates. But conventional pulse oximetry has some inherent limitations--most significantly, it has difficulty monitoring patients who are moving or who have

  8. A Novel Photodiode for Reflectance Pulse Oximetry in low-power applications

    DEFF Research Database (Denmark)

    Haahr, Rasmus Grønbek; Duun, Sune; Birkelund, Karen;


    The amount of light collected is crucial for low-power applications of pulse oximetry. In this work a novel ring-shaped backside photodiode has been developed for a wearable reflectance pulse oximeter. The photodiode is proven to work with a dual LED with wavelengths of 660 nm and 940 nm. For the......The amount of light collected is crucial for low-power applications of pulse oximetry. In this work a novel ring-shaped backside photodiode has been developed for a wearable reflectance pulse oximeter. The photodiode is proven to work with a dual LED with wavelengths of 660 nm and 940 nm....... For the purpose of continuously monitoring vital signs of a human, a temperature sensor is integrated onto the chip containing the photodiode. This biomedical multisensor chip is made for integration into "the electronic patch", an autonomous monitoring system for humans....

  9. Reproducibility, interchangeability of measures, time to measure stabilization, and reference values of two tissue oximeters in healthy volunteers (United States)

    Cournoyer, Alexis; Denault, André; Cossette, Sylvie; Fortier, Annik; Daoust, Raoul; Iseppon, Massimiliano; Chauny, Jean-Marc; Notebaert, Eric


    This study aimed to compare two tissue oximeters, the INVOS 5100c and the Equanox 7600, in terms of their reproducibility and the interchangeability of their measures. In a randomized order, three measurements were taken at six different sites on both sides of the body in 53 healthy volunteers. Intraclass correlation coefficients (ICC) and within-subject standard deviation (Sw) were calculated for each device. The ICCs were compared using Fisher r-to-z transformation and the Sw were compared using paired-sample t-tests. We found no difference between the reproducibility of the INVOS {ICC=0.92 [95% confidence interval (CI) 0.90 to 0.93]} and Equanox [ICC=0.90 (95% CI 0.88 to 0.93)] in terms of ICCs (p=0.06). However, the Equanox [Sw=1.96 (95% CI 1.91 to 2.02)] showed a better Sw than the INVOS [Sw=2.11 (95% CI 2.05 to 2.17)] (p=0.019). Also, when compared directly to stable condition, the readings produced by the two oximeters varied considerably [ICC 0.43 (95% CI 0.36 to 0.49)]. When taken individually, both tissue oximeters displayed good reproducibility, the Equanox being slightly better than the INVOS in terms of absolute reproducibility. However, when compared, the oximeters showed poor interdevices agreement. Reference values were also described.

  10. Accuracy of non-invasive measurement of haemoglobin concentration by pulse co-oximetry during steady-state and dynamic conditions in liver surgery

    NARCIS (Netherlands)

    Vos, J. J.; Kalmar, A. F.; Struys, M. M. R. F.; Porte, R. J.; Wietasch, J. K. G.; Scheeren, T. W. L.; Hendriks, H. G. D.


    Background: The Masimo Radical 7 (Masimo Corp., Irvine, CA, USA) pulse co-oximeter calculates haemoglobin concentration (SpHb) non-invasively using transcutaneous spectrophotometry. We compared SpHb with invasive satellite-lab haemoglobin monitoring (Hb(satlab)) during major hepatic resections both

  11. Exposure assessment by physiologic sampling pump--prediction of minute ventilation using a portable respiratory inductive plethysmograph system. (United States)

    Lin, Ming-I; Groves, William A; Freivalds, Andris; Lee, Eun Gyung; Harper, Martin; Slaven, James E; Lee, Larry


    A study was conducted to evaluate a portable respiratory inductive plethysmograph (RIP) as a means to estimate minute ventilation (V(E)) for use in controlling the flow rate of a physiologic sampling pump (PSP). Specific aims were to: (1) evaluate the ability of the portable RIP system to measure V(E) using a direct (individual) fixed-volume calibration method (Direct RIP model), (2) develop and evaluate the performance of indirect (group) regression models for V(E) prediction using output data from the portable RIP and subject demographic characteristics (Indirect RIP model), and (3) compare V(E) estimates from indirect and direct portable RIP calibration with indirect estimation models published previously. Nine subjects (19-44 years) were divided into calibration (n = 6) and test (n = 3) datasets and performed step-tests on three different days while wearing the portable RIP and breathing through a pneumotachometer (reference). Minute ventilation and portable RIP output including heart rate, breathing rate, and a motion index were recorded simultaneously during the 80 minute sessions. Calibration data were used to develop a regression model for V(E) prediction that was subsequently applied to the test dataset. Direct calibration of the portable RIP system produced highly variable estimates of V(E) (R2 = 0.62, average % error = 15 +/- 50) while Indirect RIP model results were highly correlated with the reference (R2 = 0.80-0.88) and estimates of total volume were within 10% of reference values on average. Although developed from a limited dataset, the Indirect RIP model provided an alternative approach to estimation of V(E) and total volume with accuracy comparable to previously published models.

  12. A Pulse Rate Estimation Algorithm Using PPG and Smartphone Camera. (United States)

    Siddiqui, Sarah Ali; Zhang, Yuan; Feng, Zhiquan; Kos, Anton


    The ubiquitous use and advancement in built-in smartphone sensors and the development in big data processing have been beneficial in several fields including healthcare. Among the basic vitals monitoring, pulse rate monitoring is the most important healthcare necessity. A multimedia video stream data acquired by built-in smartphone camera can be used to estimate it. In this paper, an algorithm that uses only smartphone camera as a sensor to estimate pulse rate using PhotoPlethysmograph (PPG) signals is proposed. The results obtained by the proposed algorithm are compared with the actual pulse rate and the maximum error found is 3 beats per minute. The standard deviation in percentage error and percentage accuracy is found to be 0.68 % whereas the average percentage error and percentage accuracy is found to be 1.98 % and 98.02 % respectively.

  13. Pulse Oximetry in the Physics Lab: A Colorful Alternative to Traditional Optics Curricula (United States)

    Kutschera, Ellynne; Dunlap, Justin C.; Byrd, Misti; Norlin, Casey; Widenhorn, Ralf


    We designed a physics laboratory exercise around pulse oximetry, a noninvasive medical technique used to assess a patient's blood oxygen saturation. An alternative to a traditional optics and light lab, this exercise teaches the principles of light absorption, spectroscopy, and the properties of light, while simultaneously studying a common medical device. Pulse oximeters are ubiquitous in clinical environments; many people who have undergone surgery or visited a hospital environment have experienced the use of this device, making it a good candidate for an investigative lab. The experiment elicits the creative process of device development from students as they conduct measurements using a blood analog that reconstructs the principles of pulse oximetry.

  14. Skin blood flow changes in anaesthetized humans: comparison between skin thermal clearance and finger pulse amplitude measurement. (United States)

    Saumet, J L; Leftheriotis, G; Dittmar, A; Delhomme, G; Degoute, C S


    The effect of general anaesthesia on skin blood flow in the left hand, measured by a new non-invasive probe using the thermal clearance method was examined. A mercury silastic gauge was placed around the third left finger and the plethysmographic wave amplitude was recorded to measure changes in finger pulse amplitude. Heart rate (HR), mean arterial blood pressure (MABP) and skin temperature were also recorded. General anaesthesia was induced by droperidol and phenoperidine injection and propanidid infusion in eight female patients. Skin thermal clearance, plethysmographic wave amplitude, HR, MABP and skin temperature were 0.40 +/- 0.02 w X m-1 degree C-1, 9 +/- 1 mm, 98 +/- 5 beats X min-1, 12.50 +/- 0.93 kPa and 33.3 +/- 3.4 degrees C respectively. The minimal value of MABP was 9.58 +/- 1.06 kPa, whereas skin thermal clearance, plethysmographic wave amplitude, HR and skin temperature increased to 0.45 +/- 0.02 w X m-1 degree C-1, 29 +/- 3 mm, 110 +/- 4 beats X min-1 and 34.4 +/- 0.4 degrees C. Changes in skin thermal clearance correlated well with plethysmographic wave amplitude. Statistically significant changes in these two parameters occurred before significant change in HR, MABP or skin temperature. The results show that the new non-invasive probe using the thermal clearance method appears to be a useful device for measuring cutaneous microcirculation in anaesthetized humans, and responds more quickly than change in skin temperature, which is a delayed effect of skin blood flow change. Our results also show that the intensity of cutaneous vasodilatation induced by general anaesthesia did not relate to the vascular tone before anaesthesia.

  15. Pulse oximetry: fundamentals and technology update

    Directory of Open Access Journals (Sweden)

    Nitzan M


    Full Text Available Meir Nitzan,1 Ayal Romem,2 Robert Koppel31Department of Physics/Electro-Optics, Jerusalem College of Technology, Jerusalem, Israel; 2Pulmonary Institute, Shaare Zedek Medical Center, Jerusalem, Israel; 3Neonatal/Perinatal Medicine, Cohen Children's Medical Center of New York/North Shore-LIJ Health System, New Hyde Park, NY, United StatesAbstract: Oxygen saturation in the arterial blood (SaO2 provides information on the adequacy of respiratory function. SaO2 can be assessed noninvasively by pulse oximetry, which is based on photoplethysmographic pulses in two wavelengths, generally in the red and infrared regions. The calibration of the measured photoplethysmographic signals is performed empirically for each type of commercial pulse-oximeter sensor, utilizing in vitro measurement of SaO2 in extracted arterial blood by means of co-oximetry. Due to the discrepancy between the measurement of SaO2 by pulse oximetry and the invasive technique, the former is denoted as SpO2. Manufacturers of pulse oximeters generally claim an accuracy of 2%, evaluated by the standard deviation (SD of the differences between SpO2 and SaO2, measured simultaneously in healthy subjects. However, an SD of 2% reflects an expected error of 4% (two SDs or more in 5% of the examinations, which is in accordance with an error of 3%–4%, reported in clinical studies. This level of accuracy is sufficient for the detection of a significant decline in respiratory function in patients, and pulse oximetry has been accepted as a reliable technique for that purpose. The accuracy of SpO2 measurement is insufficient in several situations, such as critically ill patients receiving supplemental oxygen, and can be hazardous if it leads to elevated values of oxygen partial pressure in blood. In particular, preterm newborns are vulnerable to retinopathy of prematurity induced by high oxygen concentration in the blood. The low accuracy of SpO2 measurement in critically ill patients and newborns

  16. Continuous non-invasive measurement of total hemoglobin concentration during major liver resection by pulse co-oximetry

    NARCIS (Netherlands)

    Vos, Jaap Jan; Scheeren, Thomas; Struys, Michel; Hendriks, H.G.D.


    Background and Goal of Study: The Masimo Radical 7 (V7.6.0.1, Masimo Corp, Irvine, USA) pulse co-oximeter® uses multi-wave length spectrophotometric analysis (sensor R2-25) to calculate total hemoglobin concentration (SpHb). SpHb is monitored continuously and non-invasively, which may reveal advanta

  17. Application of digital signal processing methods for the diagnosis of respiration disorders during sleep with the use of plethysmographic wave analysis (United States)

    Hatlinski, Grzegorz J.; Kornacki, Witold; Kukwa, Andrzej; Dobrowiecka, Bozena; Pikiel, Marek


    This paper proposes non-invasive solution to the problem of sleep apnea diagnosis especially in small children when sudden death syndrome is suspected. Plethysmographic wave analysis and digital signal processing algorithms are applied in order to find the effect invoked by respiratory movements of sleeping patients so as to diagnose the sleep apnea syndrome. The practical results of finding solution to problems mentioned above will be the possibility of algorithms implementation in a portable intelligent measurement system with a non-invasive monitoring of respiratory action. It works without any disturbances of sleep and respiratory movements especially in small children what could make possible in the future when continuous monitoring were applied to prevent sudden death syndrome occurrence.

  18. Pulse on Pulse

    DEFF Research Database (Denmark)

    Schmidt, Ulrik; Carlson, Merete


    Pulse on Pulse” investigates the relation between signifying processes and non-signifying material dynamism in the installation Pulse Room (2006-) by Mexican Canadian artist Rafael Lozano-Hemmer. In Pulse Room the sense of pulse is ambiguous. Biorhythms are transmitted from the pulsing energy...... and pulsating ‘room’. Hence, the visitors in Pulse Room are invited into a complex scenario that continuously oscillates between various aspects of signification (the light bulbs representing individual lives; the pulse itself as the symbolic ‘rhythm of life’) and instants of pure material processuality...... a multilayered sense of time and space that is central to the sensory experience of Pulse Room as a whole. Pulse Room is, at the very same time, an anthropomorfized archive of a past intimacy and an all-encompassing immersive environment modulating continuously in real space-time....

  19. Pulse Oximeters' Quality Assurance%脉搏血氧饱和度仪的质量保证

    Institute of Scientific and Technical Information of China (English)

    胡良勇; 吴洪景



  20. 光电脉搏血氧心率仪电路设计%Circuit Design of Photoelectric Pulse Oximeter

    Institute of Scientific and Technical Information of China (English)

    郑万挺; 陈付毅



  1. Cyclic reconstruction of 4D retinal blood flow with pulse synchronization (United States)

    Schmoll, Tilman; Lasser, Theo; Leitgeb, Rainer A.


    Doppler OCT systems allow nowadays to visualize quantitative and qualitative angiographic maps of retinal tissue. We equipped the instrument with a pulse oximeter and recorded the pulse synchronously with the resonant Doppler flow data. Recombination of tomograms according to the heart beat cycles yields full volumes for each cycle instant. We believe such multi-dimensional functional information and the ability to monitor dynamic processes over time to open exciting perspectives that ultimately contribute to a better understanding of retinal physiology and patho-physiology in-vivo.

  2. Pulse on Pulse

    DEFF Research Database (Denmark)

    Schmidt, Ulrik; Carlson, Merete


    and pulsating ‘room’. Hence, the visitors in Pulse Room are invited into a complex scenario that continuously oscillates between various aspects of signification (the light bulbs representing individual lives; the pulse itself as the symbolic ‘rhythm of life’) and instants of pure material processuality......“Pulse on Pulse” investigates the relation between signifying processes and non-signifying material dynamism in the installation Pulse Room (2006-) by Mexican Canadian artist Rafael Lozano-Hemmer. In Pulse Room the sense of pulse is ambiguous. Biorhythms are transmitted from the pulsing energy...... of the visitor’s beating heart to the blink of a fragile light bulb, thereby transforming each light bulb into a register of individual life. But at the same time the blinking light bulbs together produce a chaotically flickering light environment composed by various layers of repetitive rhythms, a vibrant...

  3. Pulse oximetry in bronchiolitis: is it needed?

    Directory of Open Access Journals (Sweden)

    Hendaus MA


    Full Text Available Mohamed A Hendaus,1,2 Fatima A Jomha,3 Ahmed H Alhammadi,1,2 1Department of Pediatrics, General Pediatrics Division, Hamad Medical Corporation, 2Weill-Cornell Medical College, Doha, Qatar; 3School of Pharmacy, Lebanese International University, Khiara, Lebanon Abstract: Infants admitted to health-care centers with acute bronchiolitis are frequently monitored with a pulse oximeter, a noninvasive method commonly used for measuring oxygen saturation. The decision to hospitalize children with bronchiolitis has been largely influenced by pulse oximetry, despite its questionable diagnostic value in delineating the severity of the illness. Many health-care providers lack the appropriate clinical fundamentals and limitations of pulse oximetry. This deficiency in knowledge might have been linked to changes in the management of bronchiolitis. The aim of this paper is to provide the current evidence on the role of pulse oximetry in bronchiolitis. We discuss the history, fundamentals of operation, and limitations of the apparatus. A search of the Google Scholar, Embase, Medline, and PubMed databases was carried out for published articles covering the use of pulse oximetry in bronchiolitis. Keywords: bronchiolitis, children, monitor, oxygen

  4. A comparison between two NIRS oximeters (INVOS, OxyPrem) using measurement on the arm of adults and head of infants after caesarean section

    DEFF Research Database (Denmark)

    Hyttel-Sorensen, Simon; Hessel, Trine Witzner; la Cour, Amalia;


    Previously the NIRS oximeter OxyPrem was calibrated by comparison to the INVOS in a blood-lipid phantom. The aim of the present study was to test this calibration clinically. During vasculur occlusions in 10 adults and after birth in 25 term infants the relationship was OxyPrem = 1.24 x INVOS - 2...

  5. Validation of a continuous penile blood-flow measurement by pulse-volume-plethysmography. (United States)

    Lavoisier, P; Barbe, R; Gally, M


    Today, in the assessment of cavernous artery blood-flow, the most commonly used technique is Doppler ultrasound velocimetry (continuous, pulsed, color-coded or power), which is often considered as the gold standard. Plethysmographic techniques and radioactive tracers have been widely used for the assessment of global penis flow variations but are not adequate for continuous blood-flow measurement. A new pulse-volume plethysmographic (PVP) device using a water-filled penile cuff was employed to assess continuous blood-flow measurement in the penis. Simultaneously Doppler velocity was recorded and served as a gold standard. A penile water-cuff is connected through a pressure tube to a three-way tap. The pulse-volume changes in the penile water-cuff are measured by means of a latex membrane placed over one of the three-way taps. The displacements of the latex are recorded by a photoplethysmograph. The third tap is connected to a 5 l perfusion bag placed 30 cm above the penis so as to maintain constant pressure in the whole device whatever the penis volume. Twenty-four volunteers were tested. The Doppler velocity signal and pulse volume of cavernous arteries were measured simultaneously after PGE1 intra-cavernous injection. Blood-flow variations were induced by increasing penis artery compression with a second penile water-cuff used as a tourniquet fitted onto the penis root, and the pressure of which could be modified by a water-filled syringe. The amplitude of the plethysmographic pulse-volume signal and the area under the Doppler velocity signal were correlated. The inter-patient (n=24) correlation ranged from 0.455 to 0.904, with a mean correlation of 0.704 and P<0.0001. PVP measurement by a water-filled cuff was validated by ultrasound velocimetry. This new continuous, non-invasive and easy-to-use technique enables physiological and physiopathological flow-measurement during sleep, under visual sexual stimulation (VSS), or following artificial erection

  6. Reduction of motion artifact in pulse oximetry by smoothed pseudo Wigner-Ville distribution

    Directory of Open Access Journals (Sweden)

    Zhang Yuan-ting


    Full Text Available Abstract Background The pulse oximeter, a medical device capable of measuring blood oxygen saturation (SpO2, has been shown to be a valuable device for monitoring patients in critical conditions. In order to incorporate the technique into a wearable device which can be used in ambulatory settings, the influence of motion artifacts on the estimated SpO2 must be reduced. This study investigates the use of the smoothed psuedo Wigner-Ville distribution (SPWVD for the reduction of motion artifacts affecting pulse oximetry. Methods The SPWVD approach is compared with two techniques currently used in this field, i.e. the weighted moving average (WMA and the fast Fourier transform (FFT approaches. SpO2 and pulse rate were estimated from a photoplethysmographic (PPG signal recorded when subject is in a resting position as well as in the act of performing four types of motions: horizontal and vertical movements of the hand, and bending and pressing motions of the finger. For each condition, 24 sets of PPG signals collected from 6 subjects, each of 30 seconds, were studied with reference to the PPG signal recorded simultaneously from the subject's other hand, which was stationary at all times. Results and Discussion The SPWVD approach shows significant improvement (p Conclusion The results suggested that the SPWVD approach could potentially be used to reduce motion artifact on wearable pulse oximeters.

  7. Continuous pulse oximetry in the general surgical ward: Nellcor N-200 versus Nellcor N-3000

    DEFF Research Database (Denmark)

    Christensen, M; Lie, C; Rosenberg, J


    New measurement principles in pulse oximetry have been introduced to decrease the incidence of false movement alarms. Experimental studies have shown that the new Nellcor Symphony N-3000 may reduce the incidence of false alarms when monitoring during different activities. We compared the Nellcor...... working principles of the two generations of oximeters were reflected in the present results derived from a clinical setting. The Nellcor Symphony N-3000 may offer an advantage compared with the Nellcor N-200, because of the reduced frequency of alarms and total time in alarm when monitoring patients...

  8. 视网膜血氧测定仪在眼科的应用进展%Application of retinal oximeter in ophthalmology

    Institute of Scientific and Technical Information of China (English)

    李静; 马建民; 王宁利


    视网膜血氧测定仪是近年来开始用于眼科疾病诊疗和研究的仪器,可以直接检测视网膜的血氧饱和度,有望为眼科医师更深入地了解眼科疾病提供了新的途径和角度,并阐明视网膜缺血对其功能的影响.目前文献已经报道,视网膜血氧测定仪在包括糖尿病性视网膜病变、视网膜中央动静脉阻塞、视网膜色素变性及青光眼性视神经病变等在内的多种眼病的诊断和治疗中有潜在价值.本文就视网膜血氧测定仪在眼科疾病中的应用进展进行综述.%Retinal oximeter is a new machine which has been used in the diagnose, treatment and research of several ophthalmic diseases for recent years.It allows ophthalmologists to gain retinal oxygen saturation directly.Therefore, retinal oximeter might be useful for ophthalmologists to understand ophthalmic diseases more deeper and clarify the impact of ischemia on retinal function.It has been reported in the literatures that retinal oximeter has potentially useful diagnostic and therapeutic indications in various eye diseases such as diabetic retinopathy, central retinal vein and artery occlusion, retinitis pigmentosa, glaucomatous optic neuropathy, et al.In this thesis, the application of retinal oximeter in ophthalmology is reviewed.

  9. Multicenter Study Validating Accuracy of a Continuous Respiratory Rate Measurement Derived From Pulse Oximetry: A Comparison With Capnography (United States)

    Bergese, Sergio D.; Kelley, Scott D.; McIntyre, Robert; Uribe, Alberto A.; Sethi, Rakesh; Watson, James N.; Addison, Paul S.


    BACKGROUND: Intermittent measurement of respiratory rate via observation is routine in many patient care settings. This approach has several inherent limitations that diminish the clinical utility of these measurements because it is intermittent, susceptible to human error, and requires clinical resources. As an alternative, a software application that derives continuous respiratory rate measurement from a standard pulse oximeter has been developed. We sought to determine the performance characteristics of this new technology by comparison with clinician-reviewed capnography waveforms in both healthy subjects and hospitalized patients in a low-acuity care setting. METHODS: Two independent observational studies were conducted to validate the performance of the Medtronic NellcorTM Respiration Rate Software application. One study enrolled 26 healthy volunteer subjects in a clinical laboratory, and a second multicenter study enrolled 53 hospitalized patients. During a 30-minute study period taking place while participants were breathing spontaneously, pulse oximeter and nasal/oral capnography waveforms were collected. Pulse oximeter waveforms were processed to determine respiratory rate via the Medtronic Nellcor Respiration Rate Software. Capnography waveforms reviewed by a clinician were used to determine the reference respiratory rate. RESULTS: A total of 23,243 paired observations between the pulse oximeter-derived respiratory rate and the capnography reference method were collected and examined. The mean reference-based respiratory rate was 15.3 ± 4.3 breaths per minute with a range of 4 to 34 breaths per minute. The Pearson correlation coefficient between the Medtronic Nellcor Respiration Rate Software values and the capnography reference respiratory rate is reported as a linear correlation, R, as 0.92 ± 0.02 (P Medtronic Nellcor Respiration Rate Software was 0.18 breaths per minute with a precision (SD) of 1.65 breaths per minute (healthy volunteers: 0.37 ± 0

  10. Using optical fibers with different modes to improve the signal-to-noise ratio of diffuse correlation spectroscopy flow-oximeter measurements (United States)

    He, Lian; Lin, Yu; Shang, Yu; Shelton, Brent J.; Yu, Guoqiang


    The dual-wavelength diffuse correlation spectroscopy (DCS) flow-oximeter is an emerging technique enabling simultaneous measurements of blood flow and blood oxygenation changes in deep tissues. High signal-to-noise ratio (SNR) is crucial when applying DCS technologies in the study of human tissues where the detected signals are usually very weak. In this study, single-mode, few-mode, and multimode fibers are compared to explore the possibility of improving the SNR of DCS flow-oximeter measurements. Experiments on liquid phantom solutions and in vivo muscle tissues show only slight improvements in flow measurements when using the few-mode fiber compared with using the single-mode fiber. However, light intensities detected by the few-mode and multimode fibers are increased, leading to significant SNR improvements in detections of phantom optical property and tissue blood oxygenation. The outcomes from this study provide useful guidance for the selection of optical fibers to improve DCS flow-oximeter measurements.

  11. Motion artefact reduction of the photoplethysmographic signal in pulse transit time measurement. (United States)

    Foo, J Y A; Wilson, S J; Williams, G R; Harris, M; Cooper, D M


    Motion artefact is a common occurrence that contaminates photoplethysmographic (PPG) measurements. To extract timing information from signals during artefact is challenging. PPG signal is very sensitive to artefacts and can be used in applications like, pulse transit time (PTT) as part of the polysomnographic studies. A correlation cancellation or signal processing approach is implemented with the adaptive cancelling filter concept and a triaxial accelerometry. PPG signals obtained from a Masimo (Reference) pulse oximeter is used as reference to compare with the reconstructed PPG signals. Different hands are used for each PPG source, one stationary while the other involves typical movements during sleep. A second Masimo pulse oximeter is used to register intensity of timing errors on commercial PPG signals. 108 PTT measurements are recorded in three different movements with PTT estimates from unprocessed PPG signals showing 35.51+/-27.42%, Masimo 50.02+/-29.40% and reconstructed 4.32+/-3.59% difference against those from the Reference PPG. The triaxial accelerometry can be used to detect the presence of artefact on PPG signals. This is useful in PTT measurements when signal contaminated with artefacts are required for further analysis, especially after and during arousals in sleep. The suggested filtering model can then reconstruct these corrupted PPG signals.


    Directory of Open Access Journals (Sweden)

    ShahForum,Chatterjee Rajib, PatelPrashant C, Kunkulol Rahul R


    Full Text Available Background: Congenital heart diseases which are dependent on the ductusarteriosus to maintain adequate oxygenation or systemic blood flow are termed as a critical congenital heart disease (CCHD. Delay in the diagnosis of CCHD is the major cause leading to morbidity and mortality in newborn infants. Clinical evaluation is likely to miss the diagnosis in first few hours of hospital stay after birth due to absence of signs and symptoms of CCHD. In the absence of clinical findings during early neonatal period, the best parameter that can be assessed is the detection of hypoxemia by pulse oximetry screening. Objectives: To record the value of Pulse Oximetry within 24 hours of birth and evaluate Pulse Oximetry as screening tool for early diagnosis of CCHD. &Methods: Longitudinal descriptive study was conducted on total 700 intramural neonates, satisfying the inclusion and exclusion criteria, who were evaluated within 24 hours of birth with currently available pulse oximeter, after the Institutional Ethical Committee approval. The study was conducted over a period of 4 months. Part-A: Neonatal Case Record, Part-B: Pulse Oximetry Screening Record, Part-C: Clinical Examination Record, Part-D: Echocardiography Record. Results and Conclusion: Total 700 neonates were screened by pulse oximeter with consecutive sampling method. 4 (0.57% subjects were detected to have positive screen and the diagnosis was confirmed by echocardiography. Study revealed that Pulse Oximetry Screening can be an important primary screening tool in routine neonatal care for early detection of Critical Congenital Heart Diseases particularly in rural setup

  13. Eight-channel time-resolved tissue oximeter for functional muscle studies (United States)

    Cubeddu, Rinaldo; Biscotti, Giovanni; Pifferi, Antonio; Taroni, Paola; Torricelli, Alessandro; Ferrari, Marco; Quaresima, Valentina


    A portable instrument for tissue oximetry based on time-resolved reflectance spectroscopy was developed. The output pulses of 2 laser diodes (683 and 785 nm, 80 MHz pulse repetition rate, 1 mW average power, 100 ps FWHM) are delayed and coupled into a multimode graded-index fiber (50/125 μm and injected into the tissue. The reflectance photons are collected by 8 independent 1 mm fibers and detected by a 16-anode photomultiplier. A time-correlated single photon counting PC board is used for the parallel acquisition of the curves. Simultaneous estimate of the transport scattering and absorption coefficients is achieved by best fitting of time-resolved reflectance curves with a standard model of Diffusion Theory. The performances of the system were tested on phantoms in terms of stability, reproducibility among channels, and accuracy in the determination of the optical properties. Preliminary in vivo measurements were performed on healthy volunteers to monitor spatial changes in calf (medical and lateral gastrocnemius) oxygen hemoglobin saturation and blood volume during dynamic plantar flexion exercise.

  14. Development of a neural network screening aid for diagnosing lower limb peripheral vascular disease from photoelectric plethysmography pulse waveforms. (United States)

    Allen, J; Murray, A


    An artificial neural network (ANN) was trained to classify photoelectric plethysmographic (PPG) pulse waveforms for the diagnosis of lower limb peripheral vascular disease (PVD). PPG pulses from the lower limbs, and pre- and post-exercise Doppler ultrasound ankle to brachial systolic blood pressure ratio measurements were obtained from patients referred to a vascular investigation laboratory. A single PPG pulse from the big toe of each leg was processed and normalized, and used as input data to the ANN. The ANN outputs represented the diagnostic classifications (normal, significant PVD and major PVD) and the ANN was trained with the ankle to brachial pressure indices (ABPI). The ANN structure consisted of an input layer (50 neuron units from the PPG pulse input), a single hidden layer (15 neurons) and an output layer (3 neurons for the PVD diagnoses). The back-propagation learning algorithm was used to train the ANN for 500 epochs with a PPG training set of pulses from 100 legs. Test data for network assessment comprised pulses from a further 50 legs (20 normal and 30 PVD, of which 15 were categorized as having major disease). A network sensitivity of 93% and specificity of 85% was achieved with respect to the Doppler ABPI standard, giving a diagnostic accuracy of 90%. The results of this study indicate that a neural network can be trained to distinguish between PPG pulses from normal and diseased lower limb arteries. The simplicity of PPG measurement and neural network classification holds promise for the screening of lower limb arterial PVD.

  15. Noninvasive Assessment of the Effect of Position and Exercise on Pulse Arrival to Peripheral Vascular Beds in Healthy Volunteers (United States)

    Obata, Yurie; Ong, Qi J.; Magruder, J. T.; Grichkevitch, Helen; Berkowitz, Dan E.; Nyhan, Daniel; Steppan, Jochen; Barodka, Viachaslau


    Background: The effects of position and exercise on pulse wave distribution across a healthy, compliant arterial tree are not fully understood. We studied the effects of exercise and position on the pattern of pulse arrival times (PATs) in healthy volunteers. Moreover, we compared the pulse arrival time ratios to the respective distance ratios between different locations. Methods: Thirteen young healthy volunteers were studied, using an electrocardiogram and plethysmograph to simultaneously record pulse wave arrival at the ear lobe, index finger and big toe. We compared the differences in PAT between each location at rest and post-exercise in the supine, sitting, and standing position. We also compared the PAT ratio (toe/ear, toe/finger, and finger/ear) to the corresponding pulse path distance ratios. Results: PAT was shortest at the ear then finger and longest at the toe regardless of position or exercise status. PATs were shorter post-exercise compared to rest. When transitioning from a standing to sitting or supine position, PAT to the ear decreased, while the PAT to the toe increased, and PAT to the finger didn't significantly change. PAT ratios were significantly smaller than predicted by the path distance ratios regardless of position or exercise status. Conclusions: Exercise makes PATs shorter. Standing position decrease PAT to the toe and increase to the ear. We conclude that PAT and PAT ratio represent the arterial vascular tree properties as surely as pulse transit time and pulse wave velocity. PMID:28220077

  16. Erratum to: Extracranial contamination in the INVOS 5100C versus the FORE-SIGHT ELITE cerebral oximeter: a prospective observational crossover study in volunteers. (United States)

    Greenberg, Steven; Murphy, Glenn; Shear, Torin; Patel, Aashka; Simpson, Andrew; Szokol, Joseph; Avram, Michael J; Vender, Jeffery


    In the article entitled: "Extracranial contamination in the INVOS 5100C versus the FORE-SIGHT ELITE cerebral oximeter: a prospective observational crossover study in volunteers" published in the January 2016 issue of theJournal, Can J Anesth 2016; 63: 24-30, in the second column of page 29, the second to last sentence of the first paragraph should read: "Another study by Sorenson et al. examined 15 healthy males under different physiologic conditions". The publisher apologizes most sincerely for this error.

  17. Arterial input function of an optical tracer for dynamic contrast enhanced imaging can be determined from pulse oximetry oxygen saturation measurements (United States)

    Elliott, Jonathan T.; Wright, Eric A.; Tichauer, Kenneth M.; Diop, Mamadou; Morrison, Laura B.; Pogue, Brian W.; Lee, Ting-Yim; St. Lawrence, Keith


    In many cases, kinetic modeling requires that the arterial input function (AIF)—the time-dependent arterial concentration of a tracer—be characterized. A straightforward method to measure the AIF of red and near-infrared optical dyes (e.g., indocyanine green) using a pulse oximeter is presented. The method is motivated by the ubiquity of pulse oximeters used in both preclinical and clinical applications, as well as the gap in currently available technologies to measure AIFs in small animals. The method is based on quantifying the interference that is observed in the derived arterial oxygen saturation (SaO2) following a bolus injection of a light-absorbing dye. In other words, the change in SaO2 can be converted into dye concentration knowing the chromophore-specific extinction coefficients, the true arterial oxygen saturation, and total hemoglobin concentration. A simple error analysis was performed to highlight potential limitations of the approach, and a validation of the method was conducted in rabbits by comparing the pulse oximetry method with the AIF acquired using a pulse dye densitometer. Considering that determining the AIF is required for performing quantitative tracer kinetics, this method provides a flexible tool for measuring the arterial dye concentration that could be used in a variety of applications.

  18. 双波长视网膜血氧测量系统%Dual-wavelength Retinal Oximeter

    Institute of Scientific and Technical Information of China (English)

    先永利; 戴云; 高椿明; 杜睿


    In order to measure retinal oxygen saturation, a dual-wavelength retinal oximeter based on commercial fundus camera was designed. The system made the retinal image of the commercial fundus camera second imaging, and simultaneously collected dual-wavelength images that respectively represented the same absorption coefficient wavelength images and the different one of oxygenated hemoglobin and de-oxygenated hemoglobin. The retinal oxygen saturation was finally measured after image registration, vessel segmentation and calculation of optic density ratio of the two images. The means oxygen saturation of artery and venules in health human for repeated measurements were 92.85% and 56.75%, respectively.The mean standard deviation was 2.41% for arterioles and 3.63% for venules.The data demonstrate that the system is reliable and reproducible. The system can obtain retinal structural imaging, which provides a useful tool for research of life sciences and diagnosis of retinal-related diseases.%为了测量视网膜血氧饱和度,本文设计一种以商业眼底相机为平台的双波长视网膜血氧测量系统。该系统将商业眼底相机输出的视网膜像进行二次成像,同时采集含氧血红蛋白和还原血红蛋白的等吸收波段和非等吸收波段图像。对获取的双波长图像进行图像配准、血管分割、光密度比计算等一系列运算,最终完成视网膜血管血氧饱和度的测量。对健康人眼进行重复性测量,动脉和静脉的血氧饱和度平均值分别是92.85%和56.75%,标准差的平均值分别为2.41%和3.63%,表明系统的准确性和重复性较好。本系统在获取视网膜结构图像的同时获得视网膜血管功能信息,可以为生命科学相关研究、眼底相关疾病的诊断提供有力工具。

  19. Neonatal pulse oximetry screening improves detecting of critical congenital heart disease

    Institute of Scientific and Technical Information of China (English)

    MA Xiao-jing; HUANG Guo-ying


    Objective Life-threatening critical congenital heart disease (cCHD) is often not detected in the neonatal period.Unrecognized cCHD results in high morbidity and mortality rates.As a non-invasive,convenient,quick and accurate measuring method,pulse oximetry is considered to be a promising strategy to screen for cCHD in neonates.This article is a review on the neonatal pulse oximetry screening for cCHD.Data sources Articles on neonatal pulse oximetry screening for cCHD were accessed from PubMed,using keywords including congenital heart defects,neonatal screening and oximetry.Study selection Original articles and critical reviews selected were relevant to the review's theme.Results The factors in the course of implementation,including threshold for positive pulse-oximetry screening results,the pulse oximeters used,timing of the screening,and the measuring position,influence the accuracy of the screening.It is recommended that the screening is completed on the second day of life,before hospital discharge.Motion-tolerant pulse oximeters,which can also be applied to measure the saturation in low-perfusion conditions,should be used.The probe should be put on both the right hand and on one foot.Thresholds of <95% in either limb or a difference of >3% between the limbs as a positive result may be appropriate.It should be emphasized that pulse-oximetry screening cannot be used as the only way to detect cCHD,clinical examination is also important in this situation.Cost-benefit analysis in the United Kingdom revealed it was plausible to use pulse oximetry as an adjunct to clinical examination.However,it is still controversial as to whether pulse oximetry can be used as a routine screening method for cCHD in neonates.Conclusions Neonatal pulse oximetry screening improves detection of cCHD.Further studies should be carried out before it becomes one of the routine newborn screening programs.

  20. A Ring-shaped photodiode designed for use in a reflectance pulse oximetry sensor in wireless health monitoring applications

    DEFF Research Database (Denmark)

    Duun, Sune; Haahr, Rasmus Grønbek; Birkelund, Karen


    We report a photodiode for use in a reflectance pulse oximeter for use in autonomous and low-power homecare applications. The novelty of the reflectance pulse oximeter is a large ring shaped backside silicon pn photodiode. The ring-shaped photodiode gives optimal gathering of light and thereby en...... is demonstrated to work in a laboratory setup with a Ledtronics dual LED with wavelengths of 660 and 940 nm. Using this setup photoplethysmograms which clearly show the cardiovascular cycle have been recorded. The sensor is shown to work very well with low currents of less than 10 mA....... a radius of 3.68 mm and a width of 0.78 mm giving an area of 18 mm2. The capacitance of the photodiode is measured to 34.5 nF. The quantum efficiency of the photodiode is measured to 55% and 62% at 660 nm and 940 nm, respectively. It is acceptable for this prototype but can be improved. The sensor also has...

  1. Pulse rate variability compared with Heart Rate Variability in children with and without sleep disordered breathing. (United States)

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


    Heart Rate Variability (HRV), the variation of time intervals between heartbeats, is one of the most promising and widely used quantitative markers of autonomic activity. Traditionally, HRV is measured as the series of instantaneous cycle intervals obtained from the electrocardiogram (ECG). In this study, we investigated the estimation of variation in heart rate from a photoplethysmography (PPG) signal, called pulse rate variability (PRV), and assessed its accuracy as an estimate of HRV in children with and without sleep disordered breathing (SDB). We recorded raw PPGs from 72 children using the Phone Oximeter, an oximeter connected to a mobile phone. Full polysomnography including ECG was simultaneously recorded for each subject. We used correlation and Bland-Altman analysis for comparing the parameters of HRV and PRV between two groups of children. Significant correlation (r > 0.90, p < 0.05) and close agreement were found between HRV and PRV for mean intervals, standard deviation of intervals (SDNN) and the root-mean square of the difference of successive intervals (RMSSD). However Bland-Altman analysis showed a large divergence for LF/HF ratio parameter. In addition, children with SDB had depressed SDNN and RMSSD and elevated LF/HF in comparison to children without SDB. In conclusion, PRV provides the accurate estimate of HRV in time domain analysis but does not reflect precise estimation for parameters in frequency domain.

  2. 高血压病人的光电容积脉搏波的频域分析%Frequency Domain Analysis of Pulse Oximeter Signal of Hypertension patients

    Institute of Scientific and Technical Information of China (English)

    孟兆辉; 白净; 王苏中; 崔树起



  3. 一种血氧仪的模糊控制算法及实现%A fuzzy control algorithm and implementation of non-invasive pulse oximeter

    Institute of Scientific and Technical Information of China (English)

    王小栋; 胡平平



  4. Tracking Pulse Oximeter Findings Before, During and After Titration of Mandibular Advancement Devices (MAD) for Patients With Mild to Moderate Obstructive Sleep Apnea (OSA) (United States)


    Electroencephalogram Electro-oculogram Epworth sleepiness scale Functional outcomes of sleep questionnaire International Classification of Sleep Disorders... Classification of Sleep Disorders (ICSD). Definitions for conditions and codes for clinical practice have been established, and recommendations for...oxygen saturation during all 21 stages of sleep . Successful CP AP therapy improves the quality of life and decreases excessive sleepiness and

  5. Feasibility and accuracy of nasal alar pulse oximetry. (United States)

    Morey, T E; Rice, M J; Vasilopoulos, T; Dennis, D M; Melker, R J


    The nasal ala is an attractive site for pulse oximetry because of perfusion by branches of the external and internal carotid arteries. We evaluated the accuracy of a novel pulse oximetry sensor custom designed for the nasal ala. After IRB approval, healthy non-smoking subjects [n=12; aged 28 (23-41) yr; 6M/6F] breathed hypoxic mixtures of fresh gas by a facemask to achieve oxyhaemoglobin saturations of 70-100% measured by traditional co-oximetry from radial artery samples. Concurrent alar and finger pulse oximetry values were measured using probes designed for these sites. Data were analysed using the Bland-Altman method for multiple observations per subject. Bias, precision, and accuracy root mean square error (ARMS) over a range of 70-100% were significantly better for the alar probe compared with a standard finger probe. The mean bias for the alar and finger probes was 0.73% and 1.90% (Palar and finger probes, respectively. The within/between-subject variation for the alar and finger probes were 1.14/1.57% and 1.87/1.47%, respectively. The limits of agreement were 3.96/-2.50% and 5.48/-1.68% for the alar and finger probes, respectively. Nasal alar pulse oximetry is feasible and demonstrates accurate pulse oximetry values over a range of 70-100%. The alar probe demonstrated greater accuracy compared with a conventional finger pulse oximeter. © The Author [2014]. Published by Oxford University Press on behalf of the British Journal of Anaesthesia. All rights reserved. For Permissions, please email:

  6. Pulse Voltammetry. (United States)

    Osteryoung, Janet


    Discusses the nature of pulse voltammetry, indicating that its widespread use arises from good sensitivity and detection limits and from ease of application and low cost. Provides analytical and mechanistic applications of the procedure. (JN)

  7. Algorithm Research on Parameters Control of Non-invasive Oximeter Circuit%血氧仪电路参数调整算法研究

    Institute of Scientific and Technical Information of China (English)

    张帅; 胡平平


    In order to improve the hypoperfusion measurement accuracy and disturbance resistance performance of non-invas-ive oximeter, based on the previous monitor techniques study on low-cost and low power consumption non-invasive oximeter, we use PID algorithm to detect whether the finger has been inserted and adjust the luminosity of the LEDs, background light offset, DC offset and the final magnification to optimize the magnification capacity and dynamic range of our new circuit. Our experiments have shown that the algorithm for finger detection is quite effective and we can acquire better sampling data than other methods.%为改进血氧饱和度仪低灌注测量精度和测量性能及提高抗干扰性能,在以往低成本低功耗无创血氧监测技术方面的研究工作的基础之上,研究利用PID算法实现手指插入检测并通过调整发光管亮度、背景光偏移量和直流偏移量及末级放大倍数以最大限度的发挥新电路的放大能力和动态范围。实验表明该算法能准确检测出手指是否插入并能获得较好的采样信号。

  8. Knowledge of pulse oximetry among medical and nursing staff

    Directory of Open Access Journals (Sweden)

    Dimitrios Kosmidis


    Full Text Available The pulse oximetry is a widely used non invasive method for monitoring the arterial oxygenation. The doctors and the nurses are persons which are in charge for right interpretation of measurements, receiving suitable interventions for the management of patients. Aim: To assess nurses' and doctors' knowledge of pulse oximetry and identify training needs. Material and method: Participants in this study were 376 doctors and nurses from critical and general care settings in seven hospitals in Greece. The data collection was done through a self-administered questionnaire. Frequency of use, critical care experience, and opinions about education needs were included in demographic data. The knowledge test consisted of a 15 item, multiple-choice questionnaire, designed by researchers based on international bibliography. Results: A 70,7% of participants, use pulse oximeter often and 66,3% consider that is very useful in daily clinical practice. 83,7% didn't have some type of past education while more than 81,4% believes that they need further education. The average score for all (on a 15-point scale was 8,5. Ιn particular, the average score for each team had as follows: 10,5±2,7 for the specialized doctors, 9,6±3,1 for residents, 7,8±3,3 for the nurses and 7,4±3,4 for the nurse assistants. Low percentages of right answers were observed mainly in the questions about principles on which the pulse oximetry are based, clinical application and limitations, as well as normal ranges. Conclusion: The comprehension of pulse oximetry is insufficient, mainly in the nursing staff while totally is observed the need for further education.

  9. Pulse plating

    CERN Document Server

    Hansal, Wolfgang E G; Green, Todd; Leisner, Peter; Reichenbach, Andreas


    The electrodeposition of metals using pulsed current has achieved practical importance in recent years. Although it has long been known that changes in potential, with or without polarity reversal, can significantly affect the deposition process, the practical application of this has been slow to be adopted. This can largely be explained in terms of the complex relationship between the current regime and its effect on the electrodeposition process. In order to harness these effects, an understanding of the anodic and cathodic electrochemical processes is necessary, together with the effects of polarity reversal and the rate of such reversals. In this new monograph, the basics of metal electrodeposition from solution are laid out in great detail in seven distinct chapters. With this knowledge, the reader is able to predict how a given pulse train profile can be adopted to achieve a desired outcome. Equally important is the choice of a suitable rectifier and the ancillary control circuits to enable pulse platin...

  10. 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 (United States)

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


    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.


    Directory of Open Access Journals (Sweden)

    Dimitar Kosturkov


    Full Text Available Purpose: To conduct pulse oximetry (PO and electric pulp test (EPT on intact frontal teeth in clinically healthy patients aged between 18 and 25 years who do not have periodontal disease. Material/Methods: To achieve the aim 1058 teeth of 31 patients were studied. The following inclusion criteria for the study were set: 1. Age – 18-25 years. 2. Clinically healthy patient, who does not have any systemic diseases, do not take any medicine systematically. 3. Intact frontal teeth – without carious lesions, restorations or root canal treatment. 4. Lack of periodontal disease. Research was conducted with a pulse oximeter Contec™ - CMS60D and a custom made probe holder. Results: Average values obtained by pulse oximetry in upper jaw vary between 83% and 85%. In lower jaw – between 82% and 85%. 99% is the maximum and 48% is the minimum registered value. The average value of the measurement of all the teeth is 84%. The average saturation measured on the small finger of the right hand of the patient is 98%. The average value of EPT for all teeth is 4 μA. The maximum measured value is 20 μA, and the minimum - 1 μA. Conclusions: 1. Adequate study of the pulp includes two complementary methods – electric pulp test (evaluation of innervation and pulse oximetry (assessment of pulp microcirculation. 2. Teeth that are larger in size have larger values of PO and EPT, which is in direct relation to the size of their pulp chamber. 3. The total saturation, measured in the little finger of the right hand is greater than the one of the teeth.

  12. Pulsed thermoelectricity (United States)

    Apostol, M.; Nedelcu, M.


    A special mechanism of thermoelectric transport is described, consisting of pulses of charge carriers which "fly" periodically through the external circuit from the hot end of the sample to the cold end, with a determined duration of the "on" and "off" times of the electric contacts, while maintaining continuously the thermal contacts. It is shown that such a "resonant" ideal thermogenerator may work cyclically, with the same efficiency quotient as the ideal efficiency quotient of the thermoelectric devices operated in the usual stationary transport regime but the electric flow and power are increased, as a consequence of the concentration of the charge carriers on pulses of small spatial extent. The process is reversible, in the sense that it can be operated either as a thermoelectric generator or as an electrothermal cooler.

  13. The use of micro pulse oximetery as a new detector of tissue perfusion in solid organ transplantation. (United States)

    Rasekhi, Alireza; Sharifian, Maryam; Kazemi, Koroush; Hosseini, Seyed Ali Malek


    Vascular complications are a frequent cause of transplant failure; angiography, duplex sonography, computerized tomography (CT) scan, CT-angiography and microdialysis are the methods that were suggested for the detection of arterial obstruction after transplantation. In this study, we suggest a new method. Eight healthy adult dogs were included in the trial. All cases were operated by the same surgeon and the liver, pancreas, spleen, kidney and bowel tissue were exposed. The probes of the device, which were designed for this study, were inserted on the organ parenchyma. The device, a neonatal pulse oximeter, has two probes that were fixed by a holder in front of each other; the distance between the probes was changeable via a spring. The pulse and the oxygen saturation of the tissue were measured initially. Following this, by inducing ischemia with vessel clamping, the pulse and the oxygen saturation were measured again. The collected data were analyzed under the supervision of a statistician. In the liver and spleen, we could not detect a clear pulse wave and oxygenation. On the other hand, in the pancreas, kidney and bowel, we detected a clear curve of oxygenation and pulse in all cases. Obstruction caused significant changes: the pulse was not detected and the oxygenation decreased significantly. Our study suggests that with early diagnosis, the surgeons can detect arterial occlusion immediately and early intervention may decrease parenchymal damage. This study is the first experience in this field, and these findings need to be validated with further studies.

  14. The use of micro pulse oximetery as a new detector of tissue perfusion in solid organ transplantation

    Directory of Open Access Journals (Sweden)

    Alireza Rasekhi


    Full Text Available Vascular complications are a frequent cause of transplant failure; angiography, duplex sonography, computerized tomography (CT scan, CT-angiography and microdialysis are the methods that were suggested for the detection of arterial obstruction after transplantation. In this study, we suggest a new method. Eight healthy adult dogs were included in the trial. All cases were operated by the same surgeon and the liver, pancreas, spleen, kidney and bowel tissue were exposed. The probes of the device, which were designed for this study, were inserted on the organ parenchyma. The device, a neonatal pulse oximeter, has two probes that were fixed by a holder in front of each other; the distance between the probes was changeable via a spring. The pulse and the oxygen saturation of the tissue were measured initially. Following this, by inducing ischemia with vessel clamping, the pulse and the oxygen saturation were measured again. The collected data were analyzed under the supervision of a statistician. In the liver and spleen, we could not detect a clear pulse wave and oxygenation. On the other hand, in the pancreas, kidney and bowel, we detected a clear curve of oxygenation and pulse in all cases. Obstruction caused significant changes: the pulse was not detected and the oxygenation decreased significantly. Our study suggests that with early diagnosis, the surgeons can detect arterial occlusion immediately and early intervention may decrease parenchymal damage. This study is the first experience in this field, and these findings need to be validated with further studies.

  15. Lung cancer symptoms and pulse oximetry in the prognostic assessment of patients with lung cancer

    Directory of Open Access Journals (Sweden)

    Harada Cecilia M


    Full Text Available Abstract Background Medical oncologists continue to use performance status as a proxy for quality of life (QOL measures, as completion of QOL instruments is perceived as time consuming, may measure aspects of QOL not affected by cancer therapy, and interpretation may be unclear. The pulse oximeter is widely used in clinical practice to predict cardiopulmonary morbidity after lung resection in cancer patients, but little is known on its role outside the surgical setting. We evaluated whether the Lung Cancer Symptom Scale and pulse oximetry may contribute to the evaluation of lung cancer patients who received standard anticancer therapy. Methods We enrolled forty-one consecutive, newly diagnosed, patients with locally advanced or metastatic lung cancer in this study. We developed a survival model with the variables gender, age, histology, clinical stage, Karnofsky performance status, wasting, LCSS symptom scores, average symptom burden index, and pulse oximetry (SpO2. Results Patient and observer-rated scores were correlated, except for the fatigue subscale. The median SpO2 was 95% (range: 86 to 98, was unrelated to symptom scores, and was weakly correlated with observer cough scores. In a multivariate survival model, SpO2 > 90% and patient scores on the LCSS appetite and fatigue subscales were independent predictors of survival. Conclusion LCSS fatigue and appetite rating, and pulse oximetry should be studied further as prognostic factors in lung cancer patients.

  16. PULSE COLUMN (United States)

    Grimmett, E.S.


    This patent covers a continuous countercurrent liquidsolids contactor column having a number of contactor states each comprising a perforated plate, a layer of balls, and a downcomer tube; a liquid-pulsing piston; and a solids discharger formed of a conical section at the bottom of the column, and a tubular extension on the lowest downcomer terminating in the conical section. Between the conical section and the downcomer extension is formed a small annular opening, through which solids fall coming through the perforated plate of the lowest contactor stage. This annular opening is small enough that the pressure drop thereacross is greater than the pressure drop upward through the lowest contactor stage. (AEC)

  17. The Comparison of Pulse Oximetry and Cardiac Catheterization in Managing the Treatment of Children with Congenital Heart Disease

    Directory of Open Access Journals (Sweden)

    R Abbasi


    Full Text Available Bachground & aim: Pulse oximetry and cardiac catheterization are concerned in the treatment of children with congenital heart disease. Diagnosis of arterial oxygen saturation in patients with congenital heart disease (CHD can be used to assess and manage their effecacy. The purpose of this study was to compare pulse oximetry and cardiac catheterizations in treatment manage of children with congenital heart disease. Methods: In the present cross sectional study, 110 patients with cyanic and non syani heart disease were studied undergoing right and left heart catheterization by pulse oximetry of index finger and simultaneously, oxygen saturation was measured by cardiac catheterization. Data were analyzed with SPSS software by using Pearson correlation and linear regression. Results: A significant correlation was seen between arterial oxygen saturation measured by pulse oximetry and arterial oxygen saturation (p<0.0001 as well as heart rate, electrocardiogram and pulse oximetry (p<0.0001 respectively. Furthermore, the presence of cyanosis (p=0.001, digital clubbing of the fingers ((p=0.001, low oxygen saturation in the superior vena cava and right atrium (p=0.002 can reduce the accuracy of pulse oximetry for detection of arterial oxygen saturation. The mean right atrial pressure can effect on accuracy of pulse oximetry to detect heartbeat (p=0.034. Maximum sensitivity and specificity for detection of pulse oximetry oxygen saturation was 88 % and 88 heart rate per minute. Conclusion: Pulse oximetric is a useful tool for estimating the arterial oxygen saturation and heart rate in children with congenital heart disease (CHD and is a non-invasive method in comparison with cardiac catheterization. Key words: Pulse oximeter, Congenital Heart Disease, Cardiac Catheterization

  18. A PC-Based Pulse Oximetry Monitor for Four Patients%微机化多床位脉搏血氧饱和度监测仪

    Institute of Scientific and Technical Information of China (English)

    刘国忠; 李萍


    微机多床位脉搏血氧饱和度监测仪具有系统结构简单、灵活、存储容量大、功能强、性能价格比高等特点,且易实现多机通讯。介绍了监测仪的硬件系统组成原理及软件模块功能。%Pulse oximeters are used in many departments of a hospital. The pc-based pulse oximetry monitor for many patients has the features of simplicity, flexbility, large memory,powerful function, high ratio of performance to price, and it is easy to communicate with mul-timonitors. The principles of hardware system and the function of software block of the monitor are introduced too in this paper.

  19. Smartphone-based Continuous Blood Pressure Measurement Using Pulse Transit Time. (United States)

    Gholamhosseini, Hamid; Meintjes, Andries; Baig, Mirza; Linden, Maria


    The increasing availability of low cost and easy to use personalized medical monitoring devices has opened the door for new and innovative methods of health monitoring to emerge. Cuff-less and continuous methods of measuring blood pressure are particularly attractive as blood pressure is one of the most important measurements of long term cardiovascular health. Current methods of noninvasive blood pressure measurement are based on inflation and deflation of a cuff with some effects on arteries where blood pressure is being measured. This inflation can also cause patient discomfort and alter the measurement results. In this work, a mobile application was developed to collate the PhotoPlethysmoGramm (PPG) waveform provided by a pulse oximeter and the electrocardiogram (ECG) for calculating the pulse transit time. This information is then indirectly related to the user's systolic blood pressure. The developed application successfully connects to the PPG and ECG monitoring devices using Bluetooth wireless connection and stores the data onto an online server. The pulse transit time is estimated in real time and the user's systolic blood pressure can be estimated after the system has been calibrated. The synchronization between the two devices was found to pose a challenge to this method of continuous blood pressure monitoring. However, the implemented continuous blood pressure monitoring system effectively serves as a proof of concept. This combined with the massive benefits that an accurate and robust continuous blood pressure monitoring system would provide indicates that it is certainly worthwhile to further develop this system.

  20. Excimer Laser Pulse Compress With Pulse Feedback

    Institute of Scientific and Technical Information of China (English)


    <正>To attain a shorter laser pulse, a compressing technique called pulse feedback was developed from the saturation gain switch applied to the amplification in a discharge pumping excimer laser cavity. It can

  1. Pulsed Optics (United States)

    Hirlimann, C.

    Optics is the field of physics which comprises knowledge on the interaction between light and matter. When the superposition principle can be applied to electromagnetic waves or when the properties of matter do not depend on the intensity of light, one speaks of linear optics. This situation occurs with regular light sources such as light bulbs, low-intensity light-emitting diodes and the sun. With such low-intensity sources the reaction of matter to light can be characterized by a set of parameters such as the index of refraction, the absorption and reflection coefficients and the orientation of the medium with respect to the polarization of the light. These parameters depend only on the nature of the medium. The situation changed dramatically after the development of lasers in the early sixties, which allowed the generation of light intensities larger than a kilowatt per square centimeter. Actual large-scale short-pulse lasers can generate peak powers in the petawatt regime. In that large-intensity regime the optical parameters of a material become functions of the intensity of the impinging light. In 1818 Fresnel wrote a letter to the French Academy of Sciences in which he noted that the proportionality between the vibration of the light and the subsequent vibration of matter was only true because no high intensities were available. The intensity dependence of the material response is what usually defines nonlinear optics.

  2. Programmable pulse generator

    CERN Document Server

    Xue Zhi Hua; Duan Xiao Hui


    The author introduces the design of programmable pulse generator that is based on a micro-controller and controlled by RS232 interface of personal computer. The whole system has good stability. The pulse generator can produce TTL pulse and analog pulse. The pulse frequency can be selected by EPLD. The voltage amplitude and pulse width of analog pulse can be adjusted by analog switches and digitally-controlled potentiometers. The software development tools of computer is National Instruments LabView5.1. The front panel of this virtual instrumentation is intuitive and easy-to-use. Parameters can be selected and changed conveniently by knob and slide

  3. The accuracy of pulse oximetry in emergency department patients with severe sepsis and septic shock: a retrospective cohort study

    Directory of Open Access Journals (Sweden)

    Lord Jason A


    Full Text Available Abstract Background Pulse oximetry is routinely used to continuously and noninvasively monitor arterial oxygen saturation (SaO2 in critically ill patients. Although pulse oximeter oxygen saturation (SpO2 has been studied in several patient populations, including the critically ill, its accuracy has never been studied in emergency department (ED patients with severe sepsis and septic shock. Sepsis results in characteristic microcirculatory derangements that could theoretically affect pulse oximeter accuracy. The purposes of the present study were twofold: 1 to determine the accuracy of pulse oximetry relative to SaO2 obtained from ABG in ED patients with severe sepsis and septic shock, and 2 to assess the impact of specific physiologic factors on this accuracy. Methods This analysis consisted of a retrospective cohort of 88 consecutive ED patients with severe sepsis who had a simultaneous arterial blood gas and an SpO2 value recorded. Adult ICU patients that were admitted from any Calgary Health Region adult ED with a pre-specified, sepsis-related admission diagnosis between October 1, 2005 and September 30, 2006, were identified. Accuracy (SpO2 - SaO2 was analyzed by the method of Bland and Altman. The effects of hypoxemia, acidosis, hyperlactatemia, anemia, and the use of vasoactive drugs on bias were determined. Results The cohort consisted of 88 subjects, with a mean age of 57 years (19 - 89. The mean difference (SpO2 - SaO2 was 2.75% and the standard deviation of the differences was 3.1%. Subgroup analysis demonstrated that hypoxemia (SaO2 2 was in the 90-93% range the SaO2 was Conclusions Pulse oximetry overestimates ABG-determined SaO2 by a mean of 2.75% in emergency department patients with severe sepsis and septic shock. This overestimation is exacerbated by the presence of hypoxemia. When SaO2 needs to be determined with a high degree of accuracy arterial blood gases are recommended.

  4. Detection of pulpal blood flow in vivo with pulse oximetry in dogs

    Directory of Open Access Journals (Sweden)

    Jessica eRiehl


    Full Text Available Objective: The aim of the present study was to investigate the ability of pulse oximetry to detect blood flow within the canine tooth of dogs. Materials and methods: Dogs aged 18-138 months presenting for oral treatment and meeting the inclusion criteria underwent pulse oximetry evaluation of at least one canine tooth. Oxygen saturation (SpO2 and pulse rate values were acquired from vital canine teeth of 38 clinical patients (representing 40 total teeth with a hand-held pulse oximeter and compared to a control area. SpO2 values from the tooth and control area were recorded every 5 seconds for three 60-second intervals. The sensors were repositioned after each 60-second interval. Results: The vital teeth consistently recorded SpO2 values significantly lower than the control area. The mean vital tooth SpO2 was 85.9% (median = 87%; SD = 8.6 and the mean control area SpO2 was 97.7% (median = 98%; SD = 1.8. An age-related significant difference was noted in vital tooth SpO2 values.Conclusions: In conclusion, the present data supports the possible use of pulse oximetry to detect blood flow in canine teeth. However, there was no significant correlation between SpO2 values in the vital tooth and in the control areas. Additionally, the results were not definitive and validation of the modality with additional studies of non-vital canine teeth is needed before clinical use can be recommended.

  5. Monitoring respiration in wheezy preschool children by pulse oximetry plethysmogram analysis. (United States)

    Wertheim, David; Olden, Cathy; Symes, Liz; Rabe, Heike; Seddon, Paul


    The aim of this study was to investigate whether respiratory information can be derived from pulse oximetry plethysmogram (pleth) recordings in acutely wheezy preschool children. A digital pulse oximeter was connected via 'Bluetooth' to a notebook computer in order to acquire pleth data. Low pass filtering and frequency analysis were used to derive respiratory rate from the pleth trace; the ratio of heart rate to respiratory rate (HR/RR) was also calculated. Recordings were obtained during acute wheezy episodes in 18 children of median age 31 months and follow-up recordings from 16 of the children were obtained when they were wheeze-free. For the acutely wheezy children, frequency analysis of the pleth waveform was within 10 breaths/min of clinical assessment in 25 of 29 recordings in 15 children. For the follow-up measurements, frequency analysis of the pleth waveform showed similarly good agreement in recordings on 15 of the 16 children. Respiratory rate was higher (p < 0.001), and HR/RR ratio was lower (p = 0.03) during acute wheeze than at follow-up. This study suggests that respiratory rate can be derived from pleth traces in wheezy preschool children.

  6. Measuring arterial oxygenation in a high altitude field environment: comparing portable pulse oximetry with blood gas analysis. (United States)

    Ross, Elliot M; Matteucci, Michael J; Shepherd, Matthew; Barker, Matthew; Orr, Lance


    High altitude environments present unique medical treatment challenges. Medical providers often use small portable pulse oximetry devices to help guide their clinical decision making. A significant body of high altitude research is based on the use of these devices to monitor hypoxia, yet there is a paucity of evidence that these devices are accurate in these environments. We studied whether these devices perform accurately and reliably under true mountain conditions. Healthy unacclimatized active-duty military volunteers participating in mountain warfare training at 2100 m (6900 feet) above sea level were evaluated with several different pulse oximetry devices while in a cold weather, high altitude field environment and then had arterial blood gases (ABG) drawn using an i-STAT for comparison. The pulse oximeter readings were compared with the gold standard ABG readings. A total of 49 individuals completed the study. There was no statistically significant difference between any of the devices and the gold standard of ABG. The best performing device was the PalmSAT (PS) 8000SM finger probe with a mean difference of 2.17% and SD of 2.56 (95% CI, 1.42% to 2.92%). In decreasing order of performance were the PS 8000AA finger probe (mean ± SD, 2.54% ± 2.68%; 95% CI, 1.76% to 3.32%), the PS 8000Q ear probe (2.47% ± 4.36%; 95% CI, 1.21% to 3.75%), the Nonin Onyx 9500 (3.29% ± 3.12%; 95% CI, 2.39% to 4.20%), and finally the PS 8000R forehead reflectance sensor (5.15% ± 2.97%; 95% CI, 4.28% to 6.01%). Based on the results of this study, results of the newer portable pulse oximeters appear to be closely correlated to that of the ABG measurements when tested in true mountain conditions. Copyright © 2013 Wilderness Medical Society. Published by Elsevier Inc. All rights reserved.

  7. Radial pulse (image) (United States)

    ... heart. The arteries are the vessels with the "pulse", a rhythmic pushing of the blood in the ... a refilling of the heart chamber. To determine heart rate, one feels the beats at a pulse point ...

  8. Wrist pulse (image) (United States)

    To measure the pulse at the wrist, place the index and middle finger over the underside of the opposite wrist, below the base ... firmly with flat fingers until you feel the pulse in the radial artery.

  9. 手指血氧仪在慢性阻塞性肺疾病患者护理中的应用%Application on the finger oximeter in the nursing of patients with chronic obstructive pulmonary disease

    Institute of Scientific and Technical Information of China (English)



    Objective:To investigate the application value of finger oximeter in the nursing of patients with chronic obstructive pulmonary disease. Methods:72 patients with chronic obstructive pulmonary disease in our hospital from January 2013 to June 2014 were selected,and they were randomly divided into control group(conventional nursing intervention group)and observation group(intervention guided by the finger oximeter group). Then the sleep quality,life quality and emotional state of two groups before the nursing intervention and at different time after the nursing intervention were respectively evaluated and compared. Results:The sleep quality,life quality and emotional state score results of observation group at different time after the nursing intervention were all significantly better than those of control group,all P 〈 0. 05,the evaluation results of two groups at different time after the nursing intervention had significant differences. Conclusion:The application value of finger oximeter in the nursing of patients with chronic obstructive pulmonary disease is higher,and it is helpful for the effective improvement of comprehensive state.%目的:探讨手指血氧仪在慢性阻塞性肺疾病患者护理中的应用价值。方法:选取2013年1月~2014年6月我院72例慢性阻塞性肺疾病患者,将其随机等分为对照组(常规护理干预组)和观察组(手指血氧仪指导干预组)。比较两组患者护理干预前及护理干预后不同时间的睡眠质量、生存质量及情绪状态。结果:观察组护理干预后不同时间的睡眠质量、生存质量及情绪状态评分结果优于对照组,两组比较有统计学意义(P 〈0.05)。结论:手指血氧仪在慢性阻塞性肺疾病患者护理中的应用价值较高,有助于改善患者综合状态。

  10. Pulse-Width Jitter Measurement for Laser Diode Pulses

    Institute of Scientific and Technical Information of China (English)

    TANG Jun-Hua; WANG Yun-Cai


    @@ Theoretical analysis and experimental measurement of pulse-width jitter of diode laser pulses are presented. The expression of pulse power spectra with all amplitude jitter, timing jitter and pulse-width jitter is deduced.

  11. Design and Implementation of photoelectric pulse oximetry%光电脉搏血氧仪的设计与实现

    Institute of Scientific and Technical Information of China (English)

    刘俊微; 庞春颖; 徐伯鸾


    血氧饱和度作为供氧状态的一个重要指标,是医护人员对疾病进行预防、诊治的重要依据之一。针对当前脉搏血氧仪功耗大、稳定性差、成本与仪器精度不可兼得等缺陷,设计中给出了一种性价比高、低功耗、可进行无线传输的光电脉搏血氧仪设计方案。系统采用指夹式光电血氧探头对血氧信号进行采集,以S TM32芯片为控制核心,对采集到的信号进行分析、处理与结果显示,实现了对血氧饱和度便携、实时、连续的检测。最终设计通过使用Fluke公司生产的Index2型血氧模拟仪进行多次测试,结果表明当血氧饱和度处于60%~80%时精度为2%,80%~99%时精度为1%,脉率检测误差为±1 bpm,达到了医疗仪器的标准要求,使得本设计具有较好的使用价值。%Oxygen saturation as an important indicator of the state of oxygen is a significant basis to the health care workers on disease prevention,diagnosis and treatment.Due to the defects of the current pulse oximeter such as power consumption,poor stability,the balance between price and instrument accuracy,a cost-effective,low-power and wire-less transmission photoelectric pulse oximeter is designed.The system used oximeter finger clip to acquire the oxygen signal and took the STM32 chip as its CPU,then the collected signal is analyzed,processed and displayed on the screen,the detection of blood oxygen saturation portable real-time continuous is realized.After repeating the experi-ment under different conditions by Fluck Index2 oximeter simulator,the extensive experimental results demonstrate that the accuracy is 2%when oxygen saturation is between 60%to 80%and the accuracy is 1%when oxygen satura-tion is between 80%to 99%,the pulse rate error is less than 1 bpm.The results show that the design has reached the standard requirements for medical equipment,which makes the design has good value in use.

  12. A review of signal processing used in the implementation of the pulse oximetry photoplethysmographic fluid responsiveness parameter. (United States)

    Addison, Paul S


    ΔPOP is a physiological parameter derived from the respiration-induced change in the pulse oximetry plethysmographic (POP) waveform or "pleth." It has been proposed as a proxy for pulse pressure variation used in the determination of the response to intravascular volume expansion in hypovolemic patients. Many studies have now reported on the parameter, and many research groups have constructed algorithms for its computation from the first principles where the implementation details have been described. This review focuses on the signal processing aspects of ΔPOP, as reported in the literature, and aims to provide a comprehensive summary of the wide-ranging algorithmic strategies that have been attempted in its computation. A search was conducted for articles concerning the use of ΔPOP as a fluid responsiveness parameter. In particular, articles concerning the correlation between ΔPOP and pulse pressure variation were targeted. Comments and replies to comments by the authors in which signal processing aspects were discussed were also included in the review. The parameter is first defined, and a history of the early work surrounding pleth-based fluid responsiveness parameters is presented. This is followed by an overview of the signal processing methods used in the reported studies, including details of exclusion criteria, manual filtering (preprocessing), gain change issues, acquisition details, selection of registration periods, averaging methods, physiological influences on the pleth, and comments by the investigators themselves. It is concluded that to develop a robust, fully automated ΔPOP algorithm for use in the clinical environment, more rigorous signal processing is required. Specifically, signals should be evaluated over significant periods of time, with emphasis on the quality and temporal relevance of the information.

  13. 新型反射式体外循环血氧饱和度监测仪的设计%The design of a new reflecting oximeter for extracorporeal circulation in heart surgery

    Institute of Scientific and Technical Information of China (English)

    李景文; 龙村; 张保洲; 郎亚军; 黄兵


    A reflecting oximeter,based on the principle that blood optical absorption(or reflection)intensity is in fixed relation with blood oxygen saturation,measures the blood oxygen saturation under extracorporeal circulation in heart surgery. It consists of a converter,a driver and a central processor module,as well as a liquid-crystal display module.A one-to-three optical-fiber cable connects the reflecting probe,the central background processing system and the digital display system.It successfully resolves the problems in sensitivity and stability of the oximeter.It has such advantages as simple in structure,low in costs,and reliable in performance,etc.%反射式血氧饱和度监测仪利用血液对光辐射吸收(或反射)强度成固定测量关系的原理反映心外科体外循环下的血氧饱和度.由转换器、驱动器、中央处理模块及液晶显示模块组成.由一分三光缆连接反射探头、核心后处理系统及数字显示系统.它成功地解决了饱和度监测仪的灵敏度和稳定性的问题;具有结构简单、成本低廉、性能可靠等优点.

  14. Design and feasibility of a novel self-designed reflecting oximeter%自行设计新型反射式血氧饱和度监测仪设计与应用的可信性

    Institute of Scientific and Technical Information of China (English)

    李景文; 龙村; 张保洲; 朗亚军; 黄兵


    BACKGROUND: The blood oxygen saturation is an important physiological parameter of human hfe; it can be affected by multiple factors due to the imbalance of oxygen supply and consumption, and consequently, the normal physical metabolism is affected. The existing manufacturing techniques are complex and are used with higher demands. OBJECTIVE: To investigate the accuracy of the novel reflecting oximeter designed on the basis of reflecting principle in monitoring the variance of blood oxygen saturation with the change of its concentration. DESIGN: To introduce the structure, working principle and design of the reflecting oximeter and make comparative study with adult rabbits as the subjects. SETTING: Cardiopolmonary Bypass Department of Cardiovascular disease hospital of the Chinese Academy of MedicalSciences. MATERIALS: The study was performed at the Departments of Anesthesiology and Cardiopulmonary Bypass of the Cardiovascular Disease Hospital,Chinese Academy of Medical Sciences from August to October in 2001.Ten adult rabbits were selected. METHODS: The oximeter consists of a converter, a driver, a central processing mould and liquid-crystal monitor. It is characterized by the onethree optical cable connected with reflecting probe, postcentral management system and digital displayer. This oxmeter was developed basing on the basis of fixed relationship between blood oxygen saturation and radiant absorbency (or reflecting). In this study,cardiovascular-pulmonary bypass was established on rabbits that were then exposed to oxygen and NO mixture supply of different concentrations,and then the corresponding blood oxygen saturations were determined with the new oximeter and compared with series-wound Baite saturation meter and blood-gas analysis. MAIN OUTCOME MEASURES: The blood oxygen saturation at different concentrations determined with the reflecting oximeter and Baite saturation meter. RESULTS: At the same oxygen concentration, the blood oxygen saturation determined

  15. The Study on the Adaptive Filtering Method for Eliminating the Motion Artifact in Pulse Oximetry Measurement%脉搏血氧饱和度检测中自适应滤波消除 运动伪差的方法研究

    Institute of Scientific and Technical Information of China (English)

    张虹; 孙卫新; 金捷


    Objective  The method of eliminating the motion artif ac t in the pulse oximetry measurement was studied in order to improve the performa nce character of the pulse oximeter. Methods  The noise paramete r was constructed by using light beat in the pulse oximetry system and the LMS(Lea st Mean Square) adaptive filter was used to eliminate the effect of motion artif act. Results  The algorithm of eliminating the motion artifact i n the pulse oximeter was developed. It can successfully extract the normal Photopl ethysmographic signal from the motion artifact in calculating oxygen saturation. Conclusion  This calculating method is simple and can be proces se d in real time, and its result is reliable. It establishes the fundament for fur ther decreasing the noise of pulse oximeter.%目的 研究脉搏血氧饱和度检测系统中运动伪差的消除方法, 以提高脉搏血氧仪检测性能。方法 通过脉搏血氧仪中的双光束构造噪声 参考信号,利用最小均方自适应滤波法消除运动伪差干扰的影响。结果  建立了脉搏血氧饱和度检测中消除运动伪差的计算方法,可成功地从运动伪差中提取正常光 电容积脉搏波信号作为计算氧饱和度的依据。结论 该计算方法简单,可 用于实时处理,且测量结果可靠,为进一步抑制脉搏血氧仪噪声奠定了基础。

  16. PulseSoar

    Energy Technology Data Exchange (ETDEWEB)

    Carter, P.; Peglow, S.


    This paper is an introduction to the PulseSoar concept. PulseSoar is a hypervelocity airplane that uses existing airport facilities and current technologies to fly at the very edge of space. It will be shown that PulseSoar can fly between any two points on the globe in less than two hours with fuel efficiency exceeding current state of the art commercial airliners. In addition, it will be shown that PulseSoar avoids environmental issues concerning the ozone layer and sonic booms because of its unique flight profile. All of this can be achieved with current technology. PulseSoar does not require the development of enabling technology. It is a concept which can be demonstrated today. The importance of this idea goes beyond the technical significance`s of PulseSoar in terms of feasibility and performance. PulseSoar could provide a crucial economic advantage to America`s largest export market: commercial aircraft. PulseSoar is a breakthrough concept for addressing the emerging markets of long range and high speed aircraft. Application of PulseSoar to commercial transport could provide the US Aerospace industry a substantial lead in offering high speed/long range aircraft to the world`s airlines. The rapid emergence of a US developed high speed aircraft could also be important to our competitiveness in the Pacific Rim and South American economies. A quick and inexpensive demonstration vehicle is proposed to bang the concept to reality within two years. This discussion will address all the major technical subjects encompassed by PulseSoar and identifies several near-term, and low risk, applications which may be further explored with the initial demonstration vehicle. What is PulseSoar? PulseSoar could enable high speed, high altitude and long range flight without many of the difficulties encountered by traditional hypersonic vehicles.

  17. Pulse Tube Refrigerator (United States)

    Matsubara, Yoichi

    The pulse tube refrigerator is one of the regenerative cycle refrigerators such as Stirling cycle or Gifford-McMahon cycle which gives the cooling temperature below 150 K down to liquid helium temperature. In 1963, W. E. Gifford invented a simple refrigeration cycle which is composed of compressor, regenerator and simple tube named as pulse tube which gives a similar function of the expander in Stirling or Gifford-McMahon cycle. The thermodynamically performance of this pulse tube refrigerator is inferior to that of other regenerative cycles. In 1984, however, Mikulin and coworkers made a significant advance in pulse tube configuration called as orifice pulse tube. After this, several modifications of the pulse tube hot end configuration have been developed. With those modifications, the thermodynamic performance of the pulse tube refrigerator became the same order to that of Stirling and Gifford-McMahon refrigerator. This article reviews the brief history of the pulse tube refrigerator development in the view point of its thermodynamically efficiency. Simplified theories of the energy flow in the pulse tube have also been described.

  18. Ultrashort Laser Pulse Phenomena

    CERN Document Server

    Diels, Jean-Claude


    Ultrashort Laser Pulse Phenomena, 2e serves as an introduction to the phenomena of ultra short laser pulses and describes how this technology can be used to examine problems in areas such as electromagnetism, optics, and quantum mechanics. Ultrashort Laser Pulse Phenomena combines theoretical backgrounds and experimental techniques and will serve as a manual on designing and constructing femtosecond (""faster than electronics"") systems or experiments from scratch. Beyond the simple optical system, the various sources of ultrashort pulses are presented, again with emphasis on the basic

  19. Oxygen Saturation Reference Value by Percutaneous Pulse Oximetry in Asymptomatic Newborn Babies in Nigeria: A Cross-Sectional Study

    Directory of Open Access Journals (Sweden)

    Obumneme Ezeanosike


    Full Text Available About 1/4 of all neonatal deaths in Nigeria are caused by birth asphyxia. Normal values of oxygen saturation vary according to regional altitudes. They are important for the screening of cyanotic congenital heart diseases and during newborn resuscitation. There is a dearth of such information in Nigeria. We determined reference values for oxygen saturation by pulse oximetry (SpO2 in asymptomatic newborns aged ≤7 days in Enugu at an altitude of 180 m. The study was cross-sectional. Neonates weighing ≥1500 g at birth were enrolled consecutively. Pre-and post-ductal oxygen saturation was measured using a Datex-Ohmeda Tuffsat® pulse oximeter with neonatal probes. Five hundred and fourteen babies comprising of 24 (4.4% preterm and 490 (95.3% term neonates were studied. The mean pre-ductal SpO2 of all babies was 96.1% ± 1.4% and higher than mean post-ductal SpO2 of 95.9% ± 1.4% (p = 0.022. The mean pre-ductal SpO2 were 96.1% ± 1.5% and 96.1% ± 1.3%, (p = 1.000 for males and females, respectively. The mean pre-ductal SpO2 values were higher than the mean post-ductal SpO2 for the corresponding post-natal ages.

  20. Neural networks and wavelet analysis in the computer interpretation of pulse oximetry data

    Energy Technology Data Exchange (ETDEWEB)

    Dowla, F.U.; Skokowski, P.G.; Leach, R.R. Jr.


    Pulse oximeters determine the oxygen saturation level of blood by measuring the light absorption of arterial blood. The sensor consists of red and infrared light sources and photodetectors. A method based on neural networks and wavelet analysis is developed for improved saturation estimation in the presence of sensor motion. Spectral and correlation functions of the dual channel oximetry data are used by a backpropagation neural network to characterize the type of motion. Amplitude ratios of red to infrared signals as a function of time scale are obtained from the multiresolution wavelet decomposition of the two-channel data. Motion class and amplitude ratios are then combined to obtain a short-time estimate of the oxygen saturation level. A final estimate of oxygen saturation is obtained by applying a 15 s smoothing filter on the short-time measurements based on 3.5 s windows sampled every 1.75 s. The design employs two backpropagation neural networks. The first neural network determines the motion characteristics and the second network determines the saturation estimate. Our approach utilizes waveform analysis in contrast to the standard algorithms that are based on the successful detection of peaks and troughs in the signal. The proposed algorithm is numerically efficient and has stable characteristics with a reduced false alarm rate with a small loss in detection. The method can be rapidly developed on a digital signal processing platform.

  1. Pulsed Plasma Electron Sources (United States)

    Krasik, Yakov


    Pulsed (˜10-7 s) electron beams with high current density (>10^2 A/cm^2) are generated in diodes with electric field of E > 10^6 V/cm. The source of electrons in these diodes is explosive emission plasma, which limits pulse duration; in the case E Hadas and Ya. E. Krasik, Europhysics Lett. 82, 55001 (2008).


    Cowper, G.


    A device is described for automatica1ly recording pulse annplitude distribution received from a counter. The novelty of the device consists of the over-all arrangement of conventional circuit elements to provide an easy to read permanent record of the pulse amplitude distribution during a certain time period. In the device a pulse analyzer separates the pulses according to annplitude into several channels. A scaler in each channel counts the pulses and operates a pen marker positioned over a drivable recorder sheet. Since the scalers in each channel have the sanne capacity, the control circuitry permits counting of the incoming pulses until one scaler reaches capacity, whereupon the input is removed and an internal oscillator supplies the necessary pulses to fill up the other scalers. Movement of the chart sheet is initiated wben the first scaler reaches capacity to thereby give a series of marks at spacings proportional to the time required to fill the remaining scalers, and accessory equipment marks calibration points on the recorder sheet to facilitate direct reading of the number of external pulses supplied to each scaler.

  3. Accuracy of non-invasive continuous total hemoglobin measurement by Pulse CO-Oximetry in severe traumatized and surgical bleeding patients. (United States)

    Baulig, Werner; Seifert, Burkhardt; Spahn, Donat R; Theusinger, Oliver M


    The Masimo Radical-7 Pulse CO-Oximeter (Masimo Corp., USA) non-invasively computes hemoglobin concentration (SpHb). SpHb was compared to Co-Oximeter readings (CoOxHb) of arterial samples in surgery patients of the emergency department. Forty-six patients were enrolled. The Masimo R1 25L (revision F and G) adult adhesive sensor was attached to the ring finger of the arterially cannulated hand. Before start, every 30 min during surgery and in the case of severe bleeding SpHb and CoOxHb values were documented. SpHb and post hoc adjusted SpHb (AdSpHb) values were analyzed. Linear regression analysis and Bland-Altman plot for agreement were performed. The detection failure rate of SpHb was 24.5 %. CoOxHb and SpHb showed a strong correlation (r = +0.81), but agreement was moderate [bias (LOA) of -0.6 (-3.0; +1.9)] g/dl. Positive and negative predicted value was 0.49 and 0.69. Exclusion of changes of CoOxHb values ≤1 g/dl resulted in a positive and negative predictive value of 0.66 and 1.00. Post hoc adjustment of the SpHb (AdSpHb) improved linear correlation of CoOxHb and AdSpHb [r = +0.90 (p values and predicted decreases of CoOxHb only if changes of SpHb ≤ 1.0 g/dl were excluded. The detection failure rate of SpHb was high. At present, additional refinements of the current technology are necessary to further improve performance of non-invasive hemoglobin measurement in the clinical setting.

  4. Pulsed electron beam precharger

    Energy Technology Data Exchange (ETDEWEB)

    Finney, W.C. (ed.); Shelton, W.N.


    Florida State University is investigating the concept of pulsed electron beams for fly ash precipitation. This report describes the results and data on three of the subtasks of this project and preliminary work only on the remaining five subtasks. Described are the modification of precharger for pulsed and DC energization of anode; installation of the Q/A measurement system; and modification and installation of pulsed power supply to provide both pulsed and DC energization of the anode. The other tasks include: measurement of the removal efficiency for monodisperse simulated fly ash particles; measurement of particle charge; optimization of pulse energization schedule for maximum removal efficiency; practical assessment of results; and measurement of the removal efficiency for polydisperse test particles. 15 figs., 1 tab. (CK)

  5. Pulse Distortion in Saturated Fiber Optical Parametric Chirped Pulse Amplification

    DEFF Research Database (Denmark)

    Lali-Dastjerdi, Zohreh; Da Ros, Francesco; Rottwitt, Karsten


    Fiber optical parametric chirped pulse amplification is experimentally compared for different chirped pulses in the picosecond regime. The amplified chirped pulses show distortion appearing as pedestals after recompression when the amplifier is operated in saturation.......Fiber optical parametric chirped pulse amplification is experimentally compared for different chirped pulses in the picosecond regime. The amplified chirped pulses show distortion appearing as pedestals after recompression when the amplifier is operated in saturation....

  6. Research and Development of the Portable Multiparameter Monitor--Pulse Oximeter%便携式多参数监护仪的研制与开发——脉搏血氧测量仪

    Institute of Scientific and Technical Information of China (English)

    罗剑; 雷勇; 涂国强; 侯海军


    便携式多参数监护仪在医院、急救和家庭监护系统中扮演着越来越重要的角色.系统以Intel XScale处理器的嵌入式平台作为数据处理和显示平台,脉搏信号的采集端通过无线射频集成芯片nRF905与嵌入式平台实现数据通信.在硬件上实现了光传感器的双光束时序控制、数据采集和无线通信,在嵌入式平台上运用了数字信号处理算法和计算脉率、血氧饱和度的算法,有效地克服了测量信号的噪声干扰.

  7. 动脉血气及脉搏氧饱和度监测在内科胸腔镜术中的应用%The value of arterial blood gas analysis and pulse oximeter in medical thoracoscopy

    Institute of Scientific and Technical Information of China (English)

    刘国梁; 薛立福


    目的研究动脉血气及脉搏氧饱和度监测在开放式胸腔镜术中的应用价值.方法前瞻性监测15例接受开放式胸腔镜术患者术前、术中、术后的呼吸、血压、心率、ECG、动脉血气、肺功能指标,并分析术中脉搏氧饱度变化及其与动脉血气指标的相关性及与手术并发症的关系.结果 15例患者术前、术中、术后呼吸、脉搏、心率、血压、血气指标(pH值、PaO2、SaO2、PaCO2)皆无明显变化,无显著统计学差异(P>0.05);15例患者中有10例术中出现一过性ECG变化.出现ECG变化者术中30min BE高于未发生者,差异均有显著统计学意义(P<0.05);心脏并发症的发生与术中VC<1.0L、FEV1<0.5L高度相关(P<0.05).结论内科胸腔镜术中心脏并发症的发生与患者术中肺功能减低有关,单独监测动脉血气分析及脉搏氧饱和度对于预防内科胸腔镜术中心脏并发症的价值有限,必需结合肺功能指标进行评估.

  8. 硬脊膜外间隙阻滞对脉搏氧饱和度仪测定时间的影响%The Effect of Epidural Blockade on Pulse Oximeter Detection Time

    Institute of Scientific and Technical Information of China (English)



    目的研究观察颈胸段和腰骶段硬脊膜外间隙阻滞对脉搏氧饱和度仪测定时间(PODT)的影响.方法选择33例ASA Ⅰ级和年龄16~40岁拟在硬脊膜外间隙阻滞下施择期外科手术的患者,根据硬脊膜外间隙阻滞的部位将患者分成两组:Ⅰ组,颈胸段硬脊膜外间隙阻滞(n=16);Ⅱ组,腰骶段硬脊膜外间隙阻滞组(n=7).应用Datex脉搏氧饱和度仪测定SpO2,Ⅰ组和Ⅱ组患者的探头分别放置在食指或食趾.PODT的测定方法是在患者尽力摒气后吸入100%O2,在硬脊膜外间隙阻滞开始前5分钟和硬脊膜外间隙阻滞5、10、15、20、30和40分钟时分别测定PODT.结果在整个测定过程中,两组患者循环功能稳定.在硬脊膜外间隙阻滞之后,所有患者的PODT逐渐缩短,并在30分钟后基本趋于稳定.与对照值相比较,两组患者在硬脊膜外间隙阻滞后各测定时间的PODT均明显缩短(P<0.01).结论硬脊膜外间隙阻滞后PODT明显缩短.PODT可作为成功硬脊膜外阻滞的一个敏感指标.

  9. R&D of a Pulse Oximeter Based on WPAN%基于WPAN的脉搏血氧饱和度检测仪的研究与实现

    Institute of Scientific and Technical Information of China (English)

    徐久强; 赵海; 孙佩刚; 尹震宇



  10. Significance of Lag Time of Pulse Oximeter Response During Anesthesia Induction in Children%脉搏氧饱和度仪反应迟滞时间在小儿麻醉诱导中的作用

    Institute of Scientific and Technical Information of China (English)



    目的研究脉搏氧饱和度仪反应迟滞时间在小儿麻醉诱导中的作用.方法将80例择期整形外科手术的小儿随机平均分成Ⅰ组和Ⅱ组.静脉麻醉诱导前小儿用Mapleson D环路自主预吸氧2min.在麻醉诱导后的无通气期,观察SpO2降至99%、95%和90%(仅Ⅰ组)的时间.Ⅰ组和Ⅱ组小儿分别在SpO2降低至90%和95%时给氧.结果SpO2降至99%和95%所需的时间在两组之间无明显差别.由于脉搏氧饱和度仪的反应迟滞时间,再建人工呼吸后小儿的SpO2在5~30秒内仍然继续下降,并达其最低值.SpO2在Ⅰ组和Ⅱ组降至的最低值分别为(78.09±L 65)%和(90.71±0.43).结论在应用脉搏氧饱和度仪监测时,在小儿预氧后的无通气期,一旦发现SpO2≤95%,应立即给氧人工通气,以免发生低氧血症.

  11. Analysis on Factors Influencing Measurement Precision of State-of-the-Art Pulse Oximeters%脉搏血氧饱和度测量精度的影响因素分析

    Institute of Scientific and Technical Information of China (English)

    蒲莉娜; 潘颂欣; 林宛华; 张元亭



  12. 一种低功耗脉搏血氧饱和度测量系统的设计%Development of a low-power pulse oximeter system

    Institute of Scientific and Technical Information of China (English)

    戴明; 王琪; 吴万庆



  13. Development of a reflective hypothenar pulse oximeter and its calibration in human hypoxia experiment%反射式小鱼际脉搏血氧计的研制及人体实验校准

    Institute of Scientific and Technical Information of China (English)

    郭涛; 曹征涛; 吕沙里; 帅万钧; 俞梦孙



  14. 脉搏血氧饱和度监测仪的原理及计量性能检测%The Principle and Examination of Measure Performance of Pulse Oximeter

    Institute of Scientific and Technical Information of China (English)




  15. 肝脏部分切除术患者脉搏血氧计连续无创检测血红蛋白的评价%Evaluation of pulse CO-Oximeter in patients undergoing hepatic resection

    Institute of Scientific and Technical Information of China (English)

    方岩; 牛犇; 缪佳敏; 陈鹤翔; 梅伟; 田玉科


    目的 比较脉搏血氧计连续无创法和血气分析法检测血红蛋白(Hb)的一致性.方法 对69名择期全麻肝脏部分切除术患者,在术中同时采用连续无创法和血气分析法检测Hb,共获得164对数据.采用配对t检验,Bland-Altman分析方法和多元线性回归分析评估2种测量方法的一致性及可能的影响因素.结果 连续无创法与血气分析法分别测得Hb (g/dL)为-12.7±1.9 vs 11.6±1.9(P <0.05);Bland-Altman方法分析2种测量方法的偏倚值为(1.1±2.8) g/dL;95%一致性界限为(-1.7 ~3.9)g/dL;多元线性回归分析提示使偏倚值发生明显变化(P<0.05)的变量包括有创Hb浓度(tHb)、平均动脉压(MAP)和灌注指数(PI).结论 Masimo Radical-7脉搏血氧计倾向于高估Hb,其准确性易受外界因素的影响;但术中维持稳定的血流动力学能够保持其检测误差的稳定,因而在肝脏部分切除术中对指导输血仍具有一定的参考意义.

  16. 可穿戴式血氧传感器的设计和定标方法研究%The Development of a Wearable Pulse Oximeter Sensor And Study of the Calibration Method

    Institute of Scientific and Technical Information of China (English)

    吴小玲; 蔡桂艳



  17. RF Pulsed Heating

    Energy Technology Data Exchange (ETDEWEB)

    Pritzkau, David P.


    RF pulsed heating is a process by which a metal is heated from magnetic fields on its surface due to high-power pulsed RF. When the thermal stresses induced are larger than the elastic limit, microcracks and surface roughening will occur due to cyclic fatigue. Pulsed heating limits the maximum magnetic field on the surface and through it the maximum achievable accelerating gradient in a normal conducting accelerator structure. An experiment using circularly cylindrical cavities operating in the TE{sub 011} mode at a resonant frequency of 11.424 GHz is designed to study pulsed heating on OFE copper, a material commonly used in normal conducting accelerator structures. The high-power pulsed RF is supplied by an X-band klystron capable of outputting 50 MW, 1.5 {micro}s pulses. The test pieces of the cavity are designed to be removable to allow testing of different materials with different surface preparations. A diagnostic tool is developed to measure the temperature rise in the cavity utilizing the dynamic Q change of the resonant mode due to heating. The diagnostic consists of simultaneously exciting a TE{sub 012} mode to steady-state in the cavity at 18 GHz and measuring the change in reflected power as the cavity is heated from high-power pulsed RF. Two experimental runs were completed. One run was executed at a calculated temperature rise of 120 K for 56 x 10{sup 6} pulses. The second run was executed at a calculated temperature rise of 82 K for 86 x 10{sup 6} pulses. Scanning electron microscope pictures show extensive damage occurring in the region of maximum temperature rise on the surface of the test pieces.

  18. Efficient Pulsed Quadrupole

    CERN Document Server

    Petzenhauser, I.; Spiller, P.; Tenholt, C.


    In order to raise the focusing gradient in case of bunched beam lines, a pulsed quadrupole was designed. The transfer channels between synchrotrons as well as the final focusing for the target line are possible applications. The quadrupole is running in a pulsed mode, which means an immense saving of energy by avoiding standby operation. Still the high gradients demand high currents. Hence a circuit had to be developed which is able to recover a significant amount of the pulsing energy for following shots. The basic design of the electrical circuit of the quadrupole is introduced. Furthermore more energy efficient circuits are presented and the limits of adaptability are considered.

  19. Pulse joining cartridges

    Energy Technology Data Exchange (ETDEWEB)

    Golovashchenko, Sergey Fedorovich; Bonnen, John Joseph Francis


    A pulsed joining tool includes a tool body that defines a cavity that receives an inner tubular member and an outer tubular member and a pulse joining cartridge. The tubular members are nested together with the cartridge being disposed around the outer tubular member. The cartridge includes a conductor, such as a wire or foil, that extends around the outer tubular member and is insulated to separate a supply segment from a return segment. A source of stored electrical energy is discharged through the conductor to join the tubular members with an electromagnetic force pulse.

  20. DogPulse

    DEFF Research Database (Denmark)

    Skovgaard, Christoffer; Thomsen, Josephine Raun; Verdezoto, Nervo;


    This paper presents DogPulse, an ambient awareness system to support the coordination of dog walking among family members at home. DogPulse augments a dog collar and leash set to activate an ambient shape-changing lamp and visualize the last time the dog was taken for a walk. The lamp gradually...... changes its form and pulsates its lights in order to keep the family members aware of the dog walking activity. We report the iterative prototyping of DogPulse, its implementation and its preliminary evaluation. Based on our initial findings, we present the limitations and lessons learned as well...

  1. Pulse measurement apparatus and method (United States)

    Marciante, John R.; Donaldson, William R.; Roides, Richard G.


    An embodiment of the invention is directed to a pulse measuring system that measures a characteristic of an input pulse under test, particularly the pulse shape of a single-shot, nano-second duration, high shape-contrast optical or electrical pulse. An exemplary system includes a multi-stage, passive pulse replicator, wherein each successive stage introduces a fixed time delay to the input pulse under test, a repetitively-gated electronic sampling apparatus that acquires the pulse train including an entire waveform of each replica pulse, a processor that temporally aligns the replicated pulses, and an averager that temporally averages the replicated pulses to generate the pulse shape of the pulse under test. An embodiment of the invention is directed to a method for measuring an optical or an electrical pulse shape. The method includes the steps of passively replicating the pulse under test with a known time delay, temporally stacking the pulses, and temporally averaging the stacked pulses. An embodiment of the invention is directed to a method for increasing the dynamic range of a pulse measurement by a repetitively-gated electronic sampling device having a rated dynamic range capability, beyond the rated dynamic range of the sampling device; e.g., enhancing the dynamic range of an oscilloscope. The embodied technique can improve the SNR from about 300:1 to 1000:1. A dynamic range enhancement of four to seven bits may be achieved.

  2. Pulse subtraction Doppler (United States)

    Mahue, Veronique; Mari, Jean Martial; Eckersley, Robert J.; Caro, Colin G.; Tang, Meng-Xing


    Recent advances have demonstrated the feasibility of molecular imaging using targeted microbubbles and ultrasound. One technical challenge is to selectively detect attached bubbles from those freely flowing bubbles and surrounding tissue. Pulse Inversion Doppler is an imaging technique enabling the selective detection of both static and moving ultrasound contrast agents: linear scatterers generate a single band Doppler spectrum, while non-linear scatterers generate a double band spectrum, one being uniquely correlated with the presence of contrast agents and non-linear tissue signals. We demonstrate that similar spectrums, and thus the same discrimination, can be obtained through a Doppler implementation of Pulse Subtraction. This is achieved by reconstructing a virtual echo using the echo generated from a short pulse transmission. Moreover by subtracting from this virtual echo the one generated from a longer pulse transmission, it is possible to fully suppress the echo from linear scatterers, while for non-linear scatterers, a signal will remain, allowing classical agent detection. Simulations of a single moving microbubble and a moving linear scatterer subject to these pulses show that when the virtual echo and the long pulse echo are used to perform pulsed Doppler, the power Doppler spectrum allows separation of linear and non-linear moving scattering. Similar results are obtained on experimental data acquired on a flow containing either microbubble contrast agents or linear blood mimicking fluid. This new Doppler method constitutes an alternative to Pulse Inversion Doppler and preliminary results suggest that similar dual band spectrums could be obtained by the combination of any non-linear detection technique with Doppler demodulation.

  3. Pulsed spallation Neutron Sources

    Energy Technology Data Exchange (ETDEWEB)

    Carpenter, J.M. [Argonne National Lab., IL (United States)


    This paper reviews the early history of pulsed spallation neutron source development at Argonne and provides an overview of existing sources world wide. A number of proposals for machines more powerful than currently exist are under development, which are briefly described. The author reviews the status of the Intense Pulsed Neutron Source, its instrumentation, and its user program, and provides a few examples of applications in fundamental condensed matter physics, materials science and technology.

  4. Four pulse recoupling (United States)

    Khaneja, Navin; Kumar, Ashutosh


    The paper describes a family of novel recoupling pulse sequences in magic angle spinning (MAS) solid state NMR, called four pulse recoupling. These pulse sequences can be employed for both homonuclear and heteronuclear recoupling experiments and are robust to dispersion in chemical shifts and rf-inhomogeneity. The homonuclear pulse sequence consists of a building block (π/2) 0 °(3π/2) ϕ°(π/2) 180 ° + ϕ°(3π/2) 180 ° where ϕ = π/n (ϕ° = 180°/n) , and n is number of blocks in a two rotor period. The heteronuclear recoupling pulse sequence consists of a building block (π/2) 0 °(3π/2) ϕ1 °(π/2) 180 ° +ϕ1 °(3π/2) 180 ° and (π/2) 0 °(3π/2) ϕ2 °(π/2) 180 ° +ϕ2 °(3π/2) 180 ° on channel I and S, where ϕ1 = 3π/2n, ϕ2 = π2/n and n is number of blocks in a two rotor period. The recoupling pulse sequences mix the y magnetization. We show that four pulse recoupling is more broadband compared to three pulse recoupling [1]. Experimental quantification of this method is shown for 13Cα-13CO, homonuclear recoupling in a sample of Glycine and 15N-13Cα, heteronuclear recoupling in Alanine. Application of this method is demonstrated on a sample of tripeptide N-formyl-[U-13C,15N]-Met-Leu-Phe-OH (MLF).

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

    Directory of Open Access Journals (Sweden)

    SH Tarig


    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

  6. Hepatopulmonary syndrome in patients with chronic liver disease: role of pulse oximetry

    Directory of Open Access Journals (Sweden)

    Olschewski Manfred


    Full Text Available Abstract Background Hepatopulmonary syndrome (HPS is a rare complication of liver diseases of different etiologies and may indicate a poor prognosis. Therefore, a simple non-invasive screening method to detect HPS would be highly desirable. In this study pulse oximetry was evaluated to identify patients with HPS. Methods In 316 consecutive patients with liver cirrhosis (n = 245, chronic hepatitis (n = 69 or non-cirrhotic portal hypertension (n = 2 arterial oxygen saturation (SaO2 was determined using a pulse oximeter. In patients with SaO2 ≤92% in supine position and/or a decrease of ≥4% after change from supine to upright position further diagnostic procedures were performed, including contrast-enhanced echocardiography and perfusion lung scan. Results Seventeen patients (5.4% had a pathological SaO2. Four patients (1.3% had HPS. HPS patients had a significant lower mean SaO2 in supine (89.7%, SD 5.4 vs. 96.0%, SD 2.3; p = 0.003 and upright position (84.3%, SD 5.0 vs. 96.0%, SD 2.4; p = 0.001 and had a lower mean PaO2 (56.2 mm Hg, SD 15.2 vs. 71.2 mm Hg, SD 20.2; p = 0.02 as compared to patients without HPS. The mean ΔSaO2 (difference between supine and upright position was 5.50 (SD 7 in HPS patients compared to non-HPS patients who showed no change (p = 0.001. There was a strong correlation between shunt volume and the SaO2 values (R = -0.94. Conclusion Arterial SaO2 determination in supine and upright position is a useful non-invasive screening test for HPS and correlates well with the intrapulmonary shunt volume.

  7. Optimal spacing between transmitting and receiving optical fibres in reflectance pulse oximetry

    Energy Technology Data Exchange (ETDEWEB)

    Hickey, M; Kyriacou, P A [School of Engineering and Mathematical Sciences, City University, Northampton Square, London, EC1V 0HB (United Kingdom)


    Splanchnic ischaemia can ultimately lead to cellular hypoxia and necrosis, and may well contribute to the development of multiple organ failures and increased mortality. Therefore, it is of utmost importance to monitor abdominal organ blood oxygen saturation (SpO{sub 2}). Pulse oximetry has been widely accepted as a reliable method for monitoring oxygen saturation of arterial blood. Animal studies have also shown it to be effective in the monitoring of blood oxygen saturation in the splanchnic region. However, commercially available pulse oximeter probes are not suitable for the continuous assessment of SpO{sub 2} in the splanchnic region. Therefore, there is a need for a new sensor technology that will allow the continuous measurement of SpO{sub 2} in the splanchnic area pre-operatively, operatively and post-operatively. For this purpose, a new fibre optic sensor and processing system utilising the principle of reflectance pulse oximetry has been developed. The accuracy in the estimation of SpO{sub 2} in pulse oximetry depends on the quality and amplitude of the photoplethysmographic (PPG) signal and for this reason an experimental procedure was carried out to examine the effect of the source-detector separation distance on the acquired PPG signals, and to ultimately select an optimal separation for the final design of the fibre-optic probe. PPG signals were obtained from the finger for different separation distances between the emitting and detecting fibres. Good quality PPG signals with large amplitudes and high signal-to-noise ratio were detected in the range of 3mm to 6mm. At separation distances between 1mm and 2mm, PPG signals were erratic with no resemblance to a conventional PPG signal. At separation distances greater than 6mm, the amplitudes of PPG signals were very small and not appropriate for processing. This investigation indicates the suitability of optical fibres as a new pulse oximetry sensor for estimating blood oxygen saturation (SpO{sub 2}) in

  8. High voltage pulse generator (United States)

    Fasching, George E.


    An improved high-voltage pulse generator has been provided which is especially useful in ultrasonic testing of rock core samples. An N number of capacitors are charged in parallel to V volts and at the proper instance are coupled in series to produce a high-voltage pulse of N times V volts. Rapid switching of the capacitors from the paralleled charging configuration to the series discharging configuration is accomplished by using silicon-controlled rectifiers which are chain self-triggered following the initial triggering of a first one of the rectifiers connected between the first and second of the plurality of charging capacitors. A timing and triggering circuit is provided to properly synchronize triggering pulses to the first SCR at a time when the charging voltage is not being applied to the parallel-connected charging capacitors. Alternate circuits are provided for controlling the application of the charging voltage from a charging circuit to be applied to the parallel capacitors which provides a selection of at least two different intervals in which the charging voltage is turned "off" to allow the SCR's connecting the capacitors in series to turn "off" before recharging begins. The high-voltage pulse-generating circuit including the N capacitors and corresponding SCR's which connect the capacitors in series when triggered "on" further includes diodes and series-connected inductors between the parallel-connected charging capacitors which allow sufficiently fast charging of the capacitors for a high pulse repetition rate and yet allow considerable control of the decay time of the high-voltage pulses from the pulse-generating circuit.

  9. Discharge pulse phenomenology (United States)

    Frederickson, A. R.


    A model was developed which places radiation induced discharge pulse results into a unified conceptual framework. Only two phenomena are required to interpret all space and laboratory results: (1) radiation produces large electrostatic fields inside insulators via the trapping of a net space charge density; and (2) the electrostatic fields initiate discharge streamer plasmas similar to those investigated in high voltage electrical insulation materials; these streamer plasmas generate the pulsing phenomena. The apparent variability and diversity of results seen is an inherent feature of the plasma streamer mechanism acting in the electric fields which is created by irradiation of the dielectrics. The implications of the model are extensive and lead to constraints over what can be done about spacecraft pulsing.

  10. Pulsed ELDOR detected NMR (United States)

    Schosseler, P.; Wacker, Th.; Schweiger, A.


    A pulsed EPR method for the determination of small hyperfine interactions in disordered systems is described. A selective preparation pulse of frequency ω mw(1) excites allowed and forbidden transitions, thereby burning spectral holes into the EPR line. The positions of the holes caused by the excitation of forbidden transitions correspond to the nuclear transition frequencies of the spin system. A selective detection pulse of frequency ω mw(2) creates an FID with integrated intensity proportional to the magnetization at frequency ω mw(2). The entire hole pattern is obtained by recording the integrated intensity of the FID while varying the frequency difference Δω mw=ω mw(1)-ω mw(2) step by step.

  11. Herophilus on pulse

    Directory of Open Access Journals (Sweden)

    Afonasin, Eugene


    Full Text Available The first detailed study of the pulse (sphygmology is associated in antiquity with Herophilus (the end of the 4th century BCE, an Alexandrian physician, renowned for his anatomical discoveries. The scholars also attribute to him a discovery of a portable and adjustable water-clock, used for measuring ‘natural’ and ‘unnatural’ pulse and, accordingly, temperature of the patient. In the article we translate the principal ancient evidences and comment upon them. We study both the practical aspects of ancient sphygmology and the theoretical speculations associated with it. Ancient theory of proportion and musical harmony allowed to build a classification of the pulses, but the medical experience did not fit well in the Procrustean bed of this rather simple theory.

  12. Pulsed Artificial Electrojet Generation (United States)

    Papadopoulos, K.


    Traditional techniques for generating low frequency signals in the ULF/ELF range (.1-100 Hz) and rely on ground based Horizontal Electric Dipole (HED) antennas. It is, furthermore, well known that a Vertical Electric Dipole (VED) is by more than 50 dB more efficient than a HED with the same dipole current moment. However, the prohibitively long length of VED antennas in the ELF/ULF range coupled with voltage limitations due to corona discharge in the atmosphere make them totally impracticable. In this paper we discuss a novel concept, inspired by the physics of the equatorial electrojet, that allows for the conversion of a ground based HED to a VED in the E-region of the equatorial ionosphere with current moment comparable to the driving HED. The paper focuses in locations near the dip-equator, where the earth's magnetic is in predominantly in the horizontal direction. The horizontal electric field associated with a pulsed HED drives a large Hall current in the ionospheric E-region, resulting in a vertical current. It is shown that the pulsed vertical current in the altitude range 80-130 km, driven by a horizontal electric field of, approximately, .1 mV/m at 100 km altitude, is of the order of kA. This results in a pulsed VED larger than 106 A-m. Such a pulsed VED will drive ELF/ULF pulses with amplitude in excess of .1 nT at a lateral range larger than few hundred kilometers. This is by three orders of magnitude larger than the one expected by a HED with comparable current moment. The paper will conclude with the description of a sneak-through technique that allows for creating pulsed electric fields in the ionosphere much larger than expected from steady state oscillatory HED antennas.

  13. Two pulse recoupling (United States)

    Khaneja, Navin; Kumar, Ashutosh


    The paper describes a family of novel recoupling pulse sequences in magic angle spinning (MAS) solid state NMR, called two pulse recoupling. These pulse sequences can be employed for both homonuclear and heteronuclear recoupling experiments and are robust to dispersion in chemical shifts and rf-inhomogeneity. The homonuclear pulse sequence consists of a building block (π)ϕ(π) - ϕ where ϕ =π/4n, and n is number of blocks in a rotor period. The recoupling block is made robust to rf-inhomogeneity by extending it to (π)ϕ(π) - ϕ(π) π + ϕ(π) π - ϕ . The heteronuclear recoupling pulse sequence consists of a building block (π)ϕ1(π)-ϕ1 and (π)ϕ2(π)-ϕ2 on channel I and S, where ϕ1 = 3π/8n, ϕ2 = π/8n and n is number of blocks in a rotor period. The recoupling block is made robust to rf-inhomogeneity by extending it to (π)ϕ1(π)-ϕ1(π) π +ϕ1(π) π -ϕ1 and (π)ϕ2(π)-ϕ2(π) π +ϕ2(π) π -ϕ2 on two channels respectively. The recoupling pulse sequences mix the z magnetization. Experimental quantification of this method is shown for 13Cα-13CO homonuclear recoupling in a sample of Glycine and 15N-13Cα heteronuclear recoupling in Alanine. Application of this method is demonstrated on a sample of tripeptide N-formyl-[U-13C,15N]-Met-Leu-Phe-OH (MLF). Compared to R-sequences (Levitt, 2002), these sequences are more robust to rf-inhomogeneity and give better sensitivity, as shown in Fig. 3.

  14. Pulse Doppler radar

    CERN Document Server

    Alabaster, Clive


    This book is a practitioner's guide to all aspects of pulse Doppler radar. It concentrates on airborne military radar systems since they are the most used, most complex, and most interesting of the pulse Doppler radars; however, ground-based and non-military systems are also included. It covers the fundamental science, signal processing, hardware issues, systems design and case studies of typical systems. It will be a useful resource for engineers of all types (hardware, software and systems), academics, post-graduate students, scientists in radar and radar electronic warfare sectors and milit

  15. Pulsed Electron Holography

    CERN Document Server

    Germann, Matthias; Escher, Conrad; Fink, Hans-Werner


    A technique of pulsed low-energy electron holography is introduced that allows for recording highly resolved holograms within reduced exposure times. Therefore, stacks of holograms are accumulated in a pulsed mode with individual acquisition times as short as 50 {\\mu}s. Subsequently, these holograms are aligned and finally superimposed. The resulting holographic record reveals previously latent high-order interference fringes and thereby pushing interference resolution into the sub-nanometer regime. In view of the non-damaging character of low-energy electrons, the method is of particular interest for structural analysis of fragile biomolecules.

  16. Analysis of pulsatile retinal movements by spectral-domain low-coherence interferometry: influence of age and glaucoma on the pulse wave.

    Directory of Open Access Journals (Sweden)

    Carolyne Dion

    Full Text Available Recent studies have shown that ocular hemodynamics and eye tissue biomechanical properties play an important role in the pathophysiology of glaucoma. Nevertheless, better, non-invasive methods to assess these characteristics in vivo are essential for a thorough understanding of degenerative mechanisms. Here, we propose to measure ocular tissue movements induced by cardiac pulsations and study the ocular pulse waveform as an indicator of tissue compliance. Using a novel, low-cost and non-invasive device based on spectral-domain low coherence interferometry (SD-LCI, we demonstrate the potential of this technique to differentiate ocular hemodynamic and biomechanical properties. We measured the axial movement of the retina driven by the pulsatile ocular blood flow in 11 young healthy individuals, 12 older healthy individuals and 15 older treated glaucoma patients using our custom-made SD-OCT apparatus. The cardiac pulse was simultaneously measured through the use of an oximeter to allow comparison. Spectral components up to the second harmonic were obtained and analyzed. For the different cohorts, we computed a few parameters that characterize the three groups of individuals by analyzing the movement of the retinal tissue at two locations, using this simple, low-cost interferometric device. Our pilot study indicates that spectral analysis of the fundus pulsation has potential for the study of ocular biomechanical and vascular properties, as well as for the study of ocular disease.

  17. SNMR pulse sequence phase cycling (United States)

    Walsh, David O; Grunewald, Elliot D


    Technologies applicable to SNMR pulse sequence phase cycling are disclosed, including SNMR acquisition apparatus and methods, SNMR processing apparatus and methods, and combinations thereof. SNMR acquisition may include transmitting two or more SNMR pulse sequences and applying a phase shift to a pulse in at least one of the pulse sequences, according to any of a variety cycling techniques. SNMR processing may include combining SNMR from a plurality of pulse sequences comprising pulses of different phases, so that desired signals are preserved and indesired signals are canceled.

  18. Pulse distortion in single-mode fibers. 3: Chirped pulses. (United States)

    Marcuse, D


    The theory of pulse distortion in single-mode fibers is extended to include laser sources that suffer a linear wavelength sweep (chirp) during the duration of the pulse. The transmitted pulse is expressed as a Fourier integral whose spectral function is given by an analytical expression in closed form. The rms width of the transmitted pulse is also expressed in closed form. Numerical examples illustrate the influence of the chirp on the shape and rms width of the pulse. A somewhat paradoxical situation exists. A given input pulse can be made arbitrarily short by a sufficiently large amount of chirping, and, after a given fiber length, this chirped pulse returns to its original width. But at this particular distance an unchirped pulse would be only [equiation] times longer. Thus chirping can improve the rate of data transmission by only 40%.

  19. Solid-state pulse forming module with adjustable pulse duration (United States)

    Wang, Langning; Liu, Jinliang; Qiu, Yongfeng; Chu, Xu; Zhang, Qingmeng


    A new solid-state pulse forming module is described in this paper. The pulse forming module is fabricated on a glass ceramic substrate, with the dimension of 250 mm × 95 mm × 4 mm. By changing the copper strips used in the pulse forming modules, the pulse duration of the obtained pulsed can range from 80 ns to 140 ns. Both the simulation and tests show that the pulse forming module has a good pulse forming ability. Under a high voltage in microsecond's time, the new pulse forming modules can hold off a voltage up to 25 kV higher than that of the previous study. In addition, future optimization for the field enhancement near the thin electrode edge has been proposed and simulated.

  20. Ultrafast optomechanical pulse picking (United States)

    Lilienfein, Nikolai; Holzberger, Simon; Pupeza, Ioachim


    State-of-the-art optical switches for coupling pulses into and/or out of resonators are based on either the electro-optic or the acousto-optic effect in transmissive elements. In high-power applications, the damage threshold and other nonlinear and thermal effects in these elements impede further improvements in pulse energy, duration, and average power. We propose a new optomechanical switching concept which is based solely on reflective elements and is suitable for switching times down to the ten-nanosecond range. To this end, an isolated section of a beam path is moved in a system comprising mirrors rotating at a high angular velocity and stationary imaging mirrors, without affecting the propagation of the beam thereafter. We discuss three variants of the concept and exemplify practical parameters for its application in regenerative amplifiers and stack-and-dump enhancement cavities. We find that optomechanical pulse picking has the potential to achieve switching rates of up to a few tens of kilohertz while supporting pulse energies of up to several joules.

  1. Pulsed electric fields (United States)

    The concept of pulsed electric fields (PEF) was first proposed in 1967 to change the behavior or microorganisms. The electric field phenomenon was identified as membrane rupture theory in the 1980s. Increasing the membrane permeability led to the application of PEF assisted extraction of cellular co...

  2. Pulsed inductive HF laser

    Energy Technology Data Exchange (ETDEWEB)

    Razhev, A M; Kargapol' tsev, E S [Institute of Laser Physics, Siberian Branch, Russian Academy of Sciences, Novosibirsk (Russian Federation); Churkin, D S; Demchuk, S V [Novosibirsk State University, Novosibirsk (Russian Federation)


    We report the results of experimentally investigated dependences of temporal, spectral and spatial characteristics of an inductive HF-laser generation on the pump conditions. Gas mixtures H{sub 2} – F{sub 2}(NF{sub 3} or SF6{sub 6}) and He(Ne) – H{sub 2} – F{sub 2}(NF{sub 3} or SF{sub 6}) were used as active media. The FWHM pulse duration reached 0.42 μs. This value corresponded to a pulsed power of 45 kW. For the first time, the emission spectrum of an inductive HF laser was investigated, which consisted of seven groups of bands with centres around the wavelengths of 2732, 2736, 2739, 2835, 2837, 2893 and 2913 nm. The cross section profile of the laser beam was a ring with a diameter of about 20 mm and width of about 5 mm. Parameters of laser operation in the repetitively pulsed regime were sufficiently stable. The amplitude instability of light pulses was no greater than 5% – 6%. (lasers)

  3. Downhole pulse tube refrigerators

    Energy Technology Data Exchange (ETDEWEB)

    Swift, G.; Gardner, D. [Los Alamos National Lab., NM (United States). Condensed Matter and Thermal Physics Group


    This report summarizes a preliminary design study to explore the plausibility of using pulse tube refrigeration to cool instruments in a hot down-hole environment. The original motivation was to maintain Dave Reagor`s high-temperature superconducting electronics at 75 K, but the study has evolved to include three target design criteria: cooling at 30 C in a 300 C environment, cooling at 75 K in a 50 C environment, cooling at both 75 K and 30 C in a 250 C environment. These specific temperatures were chosen arbitrarily, as representative of what is possible. The primary goals are low cost, reliability, and small package diameter. Pulse-tube refrigeration is a rapidly growing sub-field of cryogenic refrigeration. The pulse tube refrigerator has recently become the simplest, cheapest, most rugged and reliable low-power cryocooler. The authors expect this technology will be applicable downhole because of the ratio of hot to cold temperatures (in absolute units, such as Kelvin) of interest in deep drilling is comparable to the ratios routinely achieved with cryogenic pulse-tube refrigerators.

  4. Sequentially pulsed traveling wave accelerator (United States)

    Caporaso, George J.; Nelson, Scott D.; Poole, Brian R.


    A sequentially pulsed traveling wave compact accelerator having two or more pulse forming lines each with a switch for producing a short acceleration pulse along a short length of a beam tube, and a trigger mechanism for sequentially triggering the switches so that a traveling axial electric field is produced along the beam tube in synchronism with an axially traversing pulsed beam of charged particles to serially impart energy to the particle beam.

  5. Bacterial inactivation using pulsed light


    Elmnasser, Noura; Ritz, Magali; Leroi, Francoise; Orange, Nicole; Bakhrouf, Amina; Federighi, Michel


    Pulsed light is a new method intended for the decontamination of food surfaces using short, high frequency pulses of an intense broad spectrum. The effects of broad spectrum pulsed light on the survival of Listeria monocytogenes Scott A, Listeria monocytogenes CNL, Pseudomonas fluorescens MF37 and Photobacterium phosphoreum SF680 populations on agar and in a liquid medium were investigated during this study. The sterilisation system generated 1.5 J cm(-2) per pulse with eight lamps for 300 mu...


    A shaped pulse of intense thermal radiation, corresponding to the pulses from nuclear weapons, is obtained by the output of a QM carbon arc. A flywheel driven by a DC motor actuated a venetian blind shutter placed between a mirror and the target to control the flux. The combination produced reasonably good simulation and reproduction of the generalized field pulse.

  7. Noisy homoclinic pulse dynamics (United States)

    Eaves, T. S.; Balmforth, Neil J.


    The effect of stochastic perturbations on nearly homoclinic pulse trains is considered for three model systems: a Duffing oscillator, the Lorenz-like Shimizu-Morioka model, and a co-dimension-three normal form. Using the Duffing model as an example, it is demonstrated that the main effect of noise does not originate from the neighbourhood of the fixed point, as is commonly assumed, but due to the perturbation of the trajectory outside that region. Singular perturbation theory is used to quantify this noise effect and is applied to construct maps of pulse spacing for the Shimizu-Morioka and normal form models. The dynamics of these stochastic maps is then explored to examine how noise influences the sequence of bifurcations that take place adjacent to homoclinic connections in Lorenz-like and Shilnikov-type flows.

  8. Computationally intelligent pulsed photoacoustics (United States)

    Lukić, Mladena; Ćojbašić, Žarko; Rabasović, Mihailo D.; Markushev, Dragan D.


    In this paper, the application of computational intelligence in pulsed photoacoustics is discussed. Feedforward multilayer perception networks are applied for real-time simultaneous determination of the laser beam spatial profile and vibrational-to-translational relaxation time of the polyatomic molecules in gases. Networks are trained and tested with theoretical data adjusted for a given experimental set-up. Genetic optimization has been used for calculation of the same parameters, fitting the photoacoustic signals with a different number of generations. Observed benefits from the application of computational intelligence in pulsed photoacoustics and advantages over previously developed methods are discussed, such as real-time operation, high precision and the possibility of finding solutions in a wide range of parameters, similar to in experimental conditions. In addition, the applicability for practical uses, such as the real-time in situ measurements of atmospheric pollutants, along with possible further developments of obtained results, is argued.

  9. Micro pulse laser radar (United States)

    Spinhirne, James D. (Inventor)


    An eye safe, compact, solid state lidar for profiling atmospheric cloud and aerosol scattering is disclosed. The transmitter of the micro pulse lidar is a diode pumped micro-J pulse energy, high repetition rate Nd:YLF laser. Eye safety is obtained through beam expansion. The receiver employs a photon counting solid state Geiger mode avalanche photodiode detector. Data acquisition is by a single card multichannel scaler. Daytime background induced quantum noise is controlled by a narrow receiver field-of-view and a narrow bandwidth temperature controlled interference filter. Dynamic range of the signal is limited to optical geometric signal compression. Signal simulations and initial atmospheric measurements indicate that micropulse lider systems are capable of detecting and profiling all significant cloud and aerosol scattering through the troposphere and into the stratosphere. The intended applications are scientific studies and environmental monitoring which require full time, unattended measurements of the cloud and aerosol height structure.

  10. Magnetic Pulse Welding Technology

    Directory of Open Access Journals (Sweden)

    Ahmad K. Jassim


    Full Text Available In this paper, the benefits of using Magnetic Pulse machine which is belong to Non-conventional machine instead of conventional machine. Magnetic Pulse Technology is used for joining dissimilar metals, and for forming and cutting metals. It is a non contact technique. Magnetic field is used to generate impact magnetic pressure for welding and forming the work piece by converted the electrical energy to mechanical energy. It is enable us to design previously not possible by welding dissimilar materials and allowing to welds light and stronger materials together. It can be used to weld metallic with non metallic materials to created mechanical lock on ceramics, polymers, rubbers and composites. It is green process; there is no heat, no radiation, no gas, no smoke and sparks, therefore the emissions are negligible.

  11. Measurement of pulse lengthening with pulse energy increase in picosecond Nd:YAG laser pulses

    Energy Technology Data Exchange (ETDEWEB)

    Cutolo, A.; Zeni, L.; Berardi, V.; Bruzzese, R.; Solimeno, S.; Spinelli, N.


    Taking advantage of a new technique, we have monitored the relative variations of time duration and mode size as a function of the pulse energy for 30-ps-long Nd:YAG laser pulses. In particular, by carrying out a statistical analysis, we have observed that the pulse time duration is an increasing function of the pulse energy, according to the theoretical modeling of passively mode-locked lasers. The measurements can be easily extended to the femtosecond regime.

  12. Twitter's visual pulse


    Hare, Jonathon; Samangooei, Sina; Dupplaw, David; Lewis, Paul H.


    Millions of images are tweeted every day, yet very little research has looked at the non-textual aspect of social media communication. In this work we have developed a system to analyse streams of image data. In particular we explore trends in similar, related, evolving or even duplicated visual artefacts in the mass of tweeted image data — in short, we explore the visual pulse of Twitter.

  13. Pulse Portraiture: Pulsar timing (United States)

    Pennucci, Timothy T.; Demorest, Paul B.; Ransom, Scott M.


    Pulse Portraiture is a wideband pulsar timing code written in python. It uses an extension of the FFTFIT algorithm (Taylor 1992) to simultaneously measure a phase (TOA) and dispersion measure (DM). The code includes a Gaussian-component-based portrait modeling routine. The code uses the python interface to the pulsar data analysis package PSRCHIVE (ascl:1105.014) and also requires the non-linear least-squares minimization package lmfit (ascl:1606.014).


    Directory of Open Access Journals (Sweden)

    I. A. Bokun


    Full Text Available The structure of pulsed layer is proposed which can be suggested as a state of particulates that is blown by intermittent gas flow with speed which has the force to start material moving. Layer during one cycle is in a suspension, falling down and immobile state resulting in changes of particles arrangement as well as ways of gas flowing through layer. Moreover, it allows carrying out effective interphase heat exchange even adamant real granulation.The process of formation of impact flows is considered aw well as their influence on formation of air bubbles in pulsed layer. At startup of air blast the balance between the force of hydro-dynamic resistance is broken, on one side, and forces of gravity, particles inertia and their links with walls on the other side. The layer is transferred in the state of pulsed pseudo-fluidization, and presents gas-disperse mixture, inside of which impulse of pressure increasing is spreading to all sides as pressure waves (compression. These waves are the sources of impact flows’ formation, the force of which is two times more than during the stationary flow.The waves of pressure are divided into weak and strong ones depending on movement velocity within gas-disperse system. Weak waves are moving with a sound speed and strong ones in active phase of pulsed layer are moving over the speed of sound limit within gas-disperse system. The peculiarity of strong wave is that parameters of system (pressure, density and others are changing in discrete steps.The article describes the regime of layer’s falling down in the passive stage of cycle, which begins after finishing of gas impulse action. And suspension layer of moving up granular material is transferred in the state of falling resulting in change of the layer structure.

  15. Downhole pulse radar (United States)

    Chang, Hsi-Tien


    A borehole logging tool generates a fast rise-time, short duration, high peak-power radar pulse having broad energy distribution between 30 MHz and 300 MHz through a directional transmitting and receiving antennas having barium titanate in the electromagnetically active region to reduce the wavelength to within an order of magnitude of the diameter of the antenna. Radar returns from geological discontinuities are sampled for transmission uphole. 7 figs.

  16. Ptychographic ultrafast pulse reconstruction

    CERN Document Server

    Spangenberg, D; Brügmann, M H; Feurer, T


    We demonstrate a new ultrafast pulse reconstruction modality which is somewhat reminiscent of frequency resolved optical gating but uses a modified setup and a conceptually different reconstruction algorithm that is derived from ptychography. Even though it is a second order correlation scheme it shows no time ambiguity. Moreover, the number of spectra to record is considerably smaller than in most other related schemes which, together with a robust algorithm, leads to extremely fast convergence of the reconstruction.

  17. PULSE Pilot Certification Results

    Directory of Open Access Journals (Sweden)

    Pamela Pape-Lindstrom


    Full Text Available The pilot certification process is an ambitious, nationwide endeavor designed to motivate important changes in life sciences education that are in line with the recommendations of the 2011 Vision and Change Report: A Call to Action (American Association for the Advancement of Science [AAAS], 2011.  It is the goal of the certification process to acknowledge departments that have progressed towards full implementation of the tenets of Vision and Change and to motivate departments that have not begun to adopt the recommendations to consider doing so.  More than 70 life science departments applied to be part of the pilot certification process, funded by a National Science Foundation grant, and eight were selected based on initial evidence of transformed and innovative educational practices.  The programs chosen represent a wide variety of schools, including two-year colleges, liberal-arts institutions, regional comprehensive colleges, research universities and minority serving institutions.  Outcomes from this pilot were released June 1, 2015 (, with all eight programs being recognized as having progressed along a continuum of change.  Five levels of achievement were defined as PULSE Pilot Progression Levels.  Of the eight departments in the pilot, one achieved “PULSE Progression Level III: Accomplished”.  Six departments achieved “PULSE Progression Level II: Developing” and one pilot department achieved “PULSE Progression Level I: Beginning”.  All of the schools have made significant movement towards the recommendations of Vision and Change relative to a traditional life sciences curriculum.  Overall, the response from the eight pilot schools has been positive. 

  18. Petawatt pulsed-power accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Stygar, William A. (Albuquerque, NM); Cuneo, Michael E. (Albuquerque, NM); Headley, Daniel I. (Albuquerque, NM); Ives, Harry C. (Albuquerque, NM); Ives, legal representative; Berry Cottrell (Albuquerque, NM); Leeper, Ramon J. (Albuquerque, NM); Mazarakis, Michael G. (Albuquerque, NM); Olson, Craig L. (Albuquerque, NM); Porter, John L. (Sandia Park, NM); Wagoner; Tim C. (Albuquerque, NM)


    A petawatt pulsed-power accelerator can be driven by various types of electrical-pulse generators, including conventional Marx generators and linear-transformer drivers. The pulsed-power accelerator can be configured to drive an electrical load from one- or two-sides. Various types of loads can be driven; for example, the accelerator can be used to drive a high-current z-pinch load. When driven by slow-pulse generators (e.g., conventional Marx generators), the accelerator comprises an oil section comprising at least one pulse-generator level having a plurality of pulse generators; a water section comprising a pulse-forming circuit for each pulse generator and a level of monolithic triplate radial-transmission-line impedance transformers, that have variable impedance profiles, for each pulse-generator level; and a vacuum section comprising triplate magnetically insulated transmission lines that feed an electrical load. When driven by LTD generators or other fast-pulse generators, the need for the pulse-forming circuits in the water section can be eliminated.

  19. Pulse Distributing Manifold; Pulse Distributing Manifold

    Energy Technology Data Exchange (ETDEWEB)

    Schutting, Eberhard [Technische Univ. Graz (Austria); Sams, Theodor [AVL List GmbH, Graz (Austria); Glensvig, Michael [Forschungsgesellschaft mbH, Graz (AT). Kompetenzzentrum ' ' Das virtuelle Fahrzeug' ' (VIF)


    The Pulse Distributing Manifold is a new charge exchange method for turbocharged diesel engines with exhaust gas recirculation (EGR). The method is characterized in that the EGR mass flow is not diverted from the exhaust gas mass flow continuously, but over time broken into sub-streams. The temporal interruption is achieved by two phase-shifted outlet valves which are connected via separate manifolds only with the turbocharger or only with the EGR path. The time points of valve opening are chosen such that the turbocharger and the aftertreatment process of exhaust gas is perfused by high-energy exhaust gas of the blowdown phase while cooler and less energy-rich exhaust gas of the exhaust period is used for the exhaust gas recirculation. This increases the enthalpy for the turbocharger and the temperature for the exhaust gas treatment, while the cooling efficiency at the EGR cooler is reduced. The elimination of the continuous EGR valve has a positive effect on pumping losses. The principle functioning and the potential of this system could be demonstrated by means of a concept study using one-dimensional simulations. Without disadvantages in fuel consumption for the considered commercial vehicle engine, a reduction the EGR cooler performance by 15 % and an increase in exhaust temperature of 35 K could be achieved. The presented charge exchange method was developed, evaluated and patented within the scope of the research program 'K2-mobility' of the project partners AVL (Mainz, Federal Republic of Germany) and University of Technology Graz (Austria). The research project 'K2-Mobility' is supported by the competence center 'The virtual vehicle' Forschungsgesellschaft mbH (Graz, Austria).

  20. A History of Mild Traumatic Brain Injury affects Peripheral Pulse Oximetry during Normobaric Hypoxia

    Directory of Open Access Journals (Sweden)

    Leonard Temme


    Full Text Available Introduction: Physiological and emotional stressors increase symptoms of concussion in recently injured individuals and both forms of stress induce symptoms in people recovering from mild traumatic brain injury (mTBI but who are asymptomatic when not stressed or are at rest. Methods: Healthy asymptomatic adults (25.0 ± 5.1 years with a history of mTBI (n = 36 and matched healthy controls (n = 36 with no mTBI history were exposed to three levels of normobaric hypoxic stress generated with the Reduced Oxygen Breathing Device (ROBD (Environics, Inc., Tollande, CT, which reduced the percent oxygen by mixing sea level air with nitrogen. The ROBD reduced the percent oxygen in the breathable air from the normal 21% to 15.5% O2, 14% O2, and 13% O2. Under these conditions: (a a standard pulse oximeter recorded peripheral oxygen saturation (SpO2 and pulse rate (beats per minute, and (b the FIT (PMI, Inc., Rockville, MD recorded saccadic velocity and pupillary response dynamics to a brief light flash. Results: For all three hypoxic stress conditions the mTBI group had significantly higher SpO2 during the final minute of exposure than did the controls F(2.17,151.8 = 5.29, p < .001, η2 = .852 and the rate of SpO2 change over time was significantly shallower for the mTBI than for the controls F(2.3,161.3 = 2.863, p < .001, η2 = .569, Greenhouse-Geisser corrected. Overall, mTBI had lower pulse rate but the difference was only significant for the 14% O2 condition. FIT oculomotor measures were not sensitive to group differences. When exposed to mild or moderate normobaric hypoxic stress (15% O2: (1 SpO2 differences emerged between the mTBI and matched healthy controls, (2 heart rate trended lower in the mTBI group, and (3 FIT measures were not sensitive to group differences. Conclusion: A relatively minor hypoxic challenge can reveal measurable differences in SpO2 and heart rate in otherwise asymptomatic individuals with a history of mTBI.

  1. High-speed pulse-shape generator, pulse multiplexer (United States)

    Burkhart, Scott C.


    The invention combines arbitrary amplitude high-speed pulses for precision pulse shaping for the National Ignition Facility (NIF). The circuitry combines arbitrary height pulses which are generated by replicating scaled versions of a trigger pulse and summing them delayed in time on a pulse line. The combined electrical pulses are connected to an electro-optic modulator which modulates a laser beam. The circuit can also be adapted to combine multiple channels of high speed data into a single train of electrical pulses which generates the optical pulses for very high speed optical communication. The invention has application in laser pulse shaping for inertial confinement fusion, in optical data links for computers, telecommunications, and in laser pulse shaping for atomic excitation studies. The invention can be used to effect at least a 10.times. increase in all fiber communication lines. It allows a greatly increased data transfer rate between high-performance computers. The invention is inexpensive enough to bring high-speed video and data services to homes through a super modem.

  2. Coiled transmission line pulse generators

    Energy Technology Data Exchange (ETDEWEB)

    McDonald, Kenneth Fox (Columbia, MO)


    Methods and apparatus are provided for fabricating and constructing solid dielectric "Coiled Transmission Line" pulse generators in radial or axial coiled geometries. The pour and cure fabrication process enables a wide variety of geometries and form factors. The volume between the conductors is filled with liquid blends of monomers, polymers, oligomers, and/or cross-linkers and dielectric powders; and then cured to form high field strength and high dielectric constant solid dielectric transmission lines that intrinsically produce ideal rectangular high voltage pulses when charged and switched into matched impedance loads. Voltage levels may be increased by Marx and/or Blumlein principles incorporating spark gap or, preferentially, solid state switches (such as optically triggered thyristors) which produce reliable, high repetition rate operation. Moreover, these Marxed pulse generators can be DC charged and do not require additional pulse forming circuitry, pulse forming lines, transformers, or an a high voltage spark gap output switch. The apparatus accommodates a wide range of voltages, impedances, pulse durations, pulse repetition rates, and duty cycles. The resulting mobile or flight platform friendly cylindrical geometric configuration is much more compact, light-weight, and robust than conventional linear geometries, or pulse generators constructed from conventional components. Installing additional circuitry may accommodate optional pulse shape improvements. The Coiled Transmission Lines can also be connected in parallel to decrease the impedance, or in series to increase the pulse length.

  3. Pulsed differential pumping system

    Energy Technology Data Exchange (ETDEWEB)

    Antipov, G.N.; Bagautdinov, F.A.; Rybalov, S.V.


    A pulsed differential pumping system is described for extracting an electron beam from a shaping region at a pressure of 10/sup -5/ torr into a volume with a pressure of 10-100 torr. A fast valve is used with appropriate geometrical parameters to reduce the length of the outlet channel considerable while increasing its diameter. Test results are given. The pumping system has two sections which communicate one with the other and with the volume at the elevated pressure which is produced by gasdynamic nozzles.

  4. Pulse Field Gel Electrophoresis. (United States)

    Sharma-Kuinkel, Batu K; Rude, Thomas H; Fowler, Vance G


    Pulse Field Gel Electrophoresis (PFGE) is a powerful genotyping technique used for the separation of large DNA molecules (entire genomic DNA) after digesting it with unique restriction enzymes and applying to a gel matrix under the electric field that periodically changes direction. PFGE is a variation of agarose gel electrophoresis that permits analysis of bacterial DNA fragments over an order of magnitude larger than that with conventional restriction enzyme analysis. It provides a good representation of the entire bacterial chromosome in a single gel with a highly reproducible restriction profile, providing clearly distinct and well-resolved DNA fragments.

  5. A Pulsed Sphere Tutorial

    Energy Technology Data Exchange (ETDEWEB)

    Cullen, Dermott E. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)


    Here I attempt to explain what physically happens when we pulse an object with neutrons, specifically what we expect the time dependent behavior of the neutron population to look like. Emphasis is on the time dependent emission of both prompt and delayed neutrons. I also describe how the TART Monte Carlo transport code models this situation; see the appendix for a complete description of the model used by TART. I will also show that, as we expect, MCNP and MERCURY, produce similar results using the same delayed neutron model (again, see the appendix).

  6. Angular momentum of sound pulses. (United States)

    Lekner, John


    Three-dimensionally localized acoustic pulses in an isotropic fluid medium necessarily have transverse components of momentum density. Those with an azimuthal component of momentum density can carry angular momentum. The component of total pulse angular momentum along the direction of the total momentum is an invariant (constant in time and independent of choice of origin). The pulse energy, momentum and angular momentum are evaluated analytically for a family of localized solutions of the wave equation. In the limit where the pulses have many oscillations within their spatial extent ([Formula: see text], where k is the wavenumber and a determines the size of a pulse), the energy, momentum and angular momentum are consistent with a multiphonon representation of the pulse, each phonon having energy [Formula: see text], momentum [Formula: see text] and angular momentum [Formula: see text] (with integer m).

  7. Bipolar pulse forming line (United States)

    Rhodes, Mark A.


    A bipolar pulse forming transmission line module for linear induction accelerators having first, second, third, fourth, and fifth planar conductors which form an interleaved stack with dielectric layers between the conductors. Each conductor has a first end, and a second end adjacent an acceleration axis. The first and second planar conductors are connected to each other at the second ends, the fourth and fifth planar conductors are connected to each other at the second ends, and the first and fifth planar conductors are connected to each other at the first ends via a shorting plate adjacent the first ends. The third planar conductor is electrically connectable to a high voltage source, and an internal switch functions to short a high voltage from the first end of the third planar conductor to the first end of the fourth planar conductor to produce a bipolar pulse at the acceleration axis with a zero net time integral. Improved access to the switch is enabled by an aperture through the shorting plate and the proximity of the aperture to the switch.

  8. Heat driven pulse pump (United States)

    Benner, Steve M (Inventor); Martins, Mario S. (Inventor)


    A heat driven pulse pump includes a chamber having an inlet port, an outlet port, two check valves, a wick, and a heater. The chamber may include a plurality of grooves inside wall of the chamber. When heated within the chamber, a liquid to be pumped vaporizes and creates pressure head that expels the liquid through the outlet port. As liquid separating means, the wick, disposed within the chamber, is to allow, when saturated with the liquid, the passage of only liquid being forced by the pressure head in the chamber, preventing the vapor from exiting from the chamber through the outlet port. A plurality of grooves along the inside surface wall of the chamber can sustain the liquid, which is amount enough to produce vapor for the pressure head in the chamber. With only two simple moving parts, two check valves, the heat driven pulse pump can effectively function over the long lifetimes without maintenance or replacement. For continuous flow of the liquid to be pumped a plurality of pumps may be connected in parallel.

  9. Assembly delay line pulse generators

    CERN Document Server


    Assembly of six of the ten delay line pulse generators that will power the ten kicker magnet modules. One modulator part contains two pulse generators. Capacitors, inductances, and voltage dividers are in the oil tank on the left. Triggered high-pressure spark gap switches are on the platforms on the right. High voltage pulse cables to the kicker magnet emerge under the spark gaps. In the centre background are the assembled master gaps.

  10. Multi pulse control of entanglement

    CERN Document Server

    Uchiyama, C; Uchiyama, Chikako; Aihara, Masaki


    We study the effectiveness of multi pulse control to suppress the degradation of entanglement. Based on a linearly interacting spin-boson model, we show that the multi pulse application recovers the decay of concurrence when an entangled pair of spins interacts with a reservoir that has the non-Markovian nature. We present the effectiveness of multi pulse control for both the common bath case and the individual bath case.

  11. Method of optical self-mixing for pulse wave transit time in comparison with other methods and correlation with blood pressure (United States)

    Meigas, Kalju; Lass, Jaanus; Kattai, Rain; Karai, Deniss; Kaik, Juri


    This paper is a part of research to develop convenient method for continuous monitoring of arterial blood pressure by non-invasive and non-oscillometric way. A simple optical method, using self-mixing in a diode laser, is used for detection of skin surface vibrations near the artery. These vibrations, which can reveal the pulsate propagation of blood pressure waves along the vasculature, are used for pulse wave registration. The registration of the Pulse Wave Transit Time (PWTT) is based on computing the time delay in different regions of the human body using an ECG as a reference signal. In this study, the comparison of method of optical self-mixing with other methods as photoplethysmographic (PPG) and bioimpedance (BI) for PWTT is done. Also correlation of PWTT, obtained with different methods, with arterial blood pressure is calculated. In our study, we used a group of volunteers (34 persons) who made the bicycle exercise test. The test consisted of cycling sessions of increasing workloads during which the HR changed from 60 to 180 beats per minute. In addition, a blood pressure (NIBP) was registered with standard sphygmomanometer once per minute during the test and all NIBP measurement values were synchronized to other signals to find exact time moments where the systolic blood pressure was detected (Korotkoff sounds starting point). Computer later interpolated the blood pressure signal in order to get individual value for every heart cycle. The other signals were measured continuously during all tests. At the end of every session, a recovery period was included until person's NIBP and heart rate (HR) normalized. As a result of our study it turned out that time intervals that were calculated from plethysmographic (PPG) waveforms were in the best correlation with systolic blood pressure. The diastolic pressure does not correlate with any of the parameters representing PWTT. The pulse wave signals measured by laser and piezoelectric transducer are very similar

  12. Analysis of Pulse Modulated Control Systems (Ⅲ) Stability of Systems with Pulse Frequency Modulation and Systems with Combined Pulse Frequency and Pulse Width Modulation




    Sufficient conditions for finite pulse stability of interconnected systems with combined pulse frequency and pulse width modulation are developed in this paper using a direct method. The stability criteria established provide upper bounds on the number of pulses emitted by each modulator. The results are also applicable to those systems which contain a finite number of pulse frequency modulators and a finite number of combined pulse frequency and pulse width modulators

  13. Population inversion by chirped pulses

    Energy Technology Data Exchange (ETDEWEB)

    Lu Tianshi [Department of Mathematics and Statistics, Wichita State University, Wichita, Kansas 67260-0033 (United States)


    In this paper, we analyze the condition for complete population inversion by a chirped pulse over a finite duration. The nonadiabatic transition probability is mapped in the two-dimensional parameter space of coupling strength and detuning amplitude. Asymptotic forms of the probability are derived by the interference of nonadiabatic transitions for sinusoidal and triangular pulses. The qualitative difference between the maps for the two types of pulses is accounted for. The map is used for the design of stable inversion pulses under specific accuracy thresholds.

  14. Double pulse laser wakefield accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Changbum [Department of Physics, Pohang University of Science and Technology, Pohang 790-784 (Korea, Republic of)], E-mail:; Kim, Jin-Cheol B. [Department of Physics, Pohang University of Science and Technology, Pohang 790-784 (Korea, Republic of); Kim, Kukhee [National Fusion Reserch Center, Daejeon 305-333 (Korea, Republic of); Ko, In Soo [Department of Physics, Pohang University of Science and Technology, Pohang 790-784 (Korea, Republic of); Suk, Hyyong [Center for Advanced Accelerators, Korea Electrotechnology Research Institute, Changwon 641-120 (Korea, Republic of)


    Two-dimensional simulation studies are performed for modified laser wakefield acceleration. After one laser pulse, another identical laser pulse is sent to the plasma to amplify the wake wave resonantly. The simulation results show that the number of injected electrons is bigger than that of the single pulse case and the beam energy is higher as well. In addition, increase of the transverse amplitude is noticed in the wake wave after the second laser pulse. This shows that the transverse motion of the wake wave enhances the wave breaking for strong injection and acceleration of electron beams.

  15. Research on Human Movement with Noninvasive Tissue Oximeter Using Near Infrared Spectroscopy%用近红外组织血氧参数无损监测仪进行运动人体研究

    Institute of Scientific and Technical Information of China (English)

    林红; 习玉宝; 於辉


    利用我国自主生产的近红外组织血氧参数无损监测仪对8名中长跑运动员在功率自行车上作等级递增负荷运动时,大腿股四头肌组织中肌氧含量的变化进行监测与分析,同时测量运动员的血乳酸浓度、血容量和心率的变化。结果显示肌氧含量与运动负荷、血乳酸、血容量、心率密切相关(p<0.01)。对一人经过多次测定肌氧含量和血乳酸浓度,结果呈规律性的下降和上升,每次之间数值的横向比对,没有明显变化。由此表明,可以根据运动时骨骼肌中肌氧含量的变化来判断受试者所能承受的运动强度和在对应强度下所对应的血乳酸浓度以及肌氧下降的拐点所对应的血乳酸上升的拐点。通过调查,了解NIRS 技术在运动领域中的研究及应用的现状,分析存在的主要问题和今后的研究趋向。目的在于使大家通过对NIRS技术的不断了解,认识到我国自主生产的近红外组织血氧参数无损监测仪所测的肌氧含量指标,作为测定运动氧代谢能力是一项敏感的、无损的、实时可靠的指标,与传统有创的、离体的、繁琐的检测手段相比较具有不可替代的优势。%The present paper discusses how to monitor and analyze the relative change in muscle oxygen content in quadriceps tis-sue,and measures and records the change in blood lactate acid concentration,blood volume and heart rate when eight players who are good at middle-distance races perform grade incremental intensity exercise on cycle ergometer by using noninvasive tissue oximeter with near infrared spectroscopy produced by China independently.The results show that muscle oxygen content has a close relationship(p<0. 01)with exercise load,blood lactic acid,blood volume and heart rate.When determined muscle oxygen content and blood lactate acid concentration was determined for many times to the same person,the test proved regular falling

  16. Theoretical Studies of the Output Pulse with Variation of the Pumping Pulse for RF Excited CO2 Pulsed Waveguide Laser

    Institute of Scientific and Technical Information of China (English)

    A Rauf; ZHOU Wei; XIN Jian-guo


    The behavior of a RF-excited waveguide CO2 laser in the pulse regime is studied theoretically. The output pulse evolution is studied by applying three types of pulses namely the square, sine and the triangular ones as the excitation pulses. The frequency dependence behavior of the output pulse is also presented.

  17. Pulse-shaping strategies in short-pulse fiber amplifiers

    Energy Technology Data Exchange (ETDEWEB)

    Schimpf, Damian Nikolaus


    Ultrashort pulse lasers are an important tool in scientific and industrial applications. However, many applications are demanding higher average powers from these ultrashort pulse sources. This can be achieved by combining direct diode pumping with novel gain media designs. In particular, ultrashort pulse fiber lasers are now delivering average powers in the kW range. However, the design of fiber lasers, producing pulses with high peak-powers, is challenging due to the impact of nonlinear effects. To significantly reduce these detrimental effects in ultrashort pulse fiber amplifers, the combination of chirped pulse amplification (CPA) and large mode area fibers is employed. Using these methods, the pulse energy of fiber lasers has been steadily increasing for the past few years. Recently, a fiber-based CPA-system has been demonstrated which produces pulse energies of around 1 mJ. However, both the stretching and the enlargement of the mode area are limited, and therefore, the impact of nonlinearity is still noticed in systems employing such devices. The aim of this thesis is the analysis of CPA-systems operated beyond the conventional nonlinear limit, which corresponds to accumulated nonlinear phase-shifts around 1 rad. This includes a detailed discussion of the influence of the nonlinear effect self-phase modulation on the output pulse of CPA-systems. An analytical model is presented. Emphasis is placed on the design of novel concepts to control the impact of self-phase modulation. Pulse-shaping is regarded as a powerful tool to accomplish this goal. Novel methods to control the impact of SPM are experimentally demonstrated. The design of these concepts is based on the theoretical findings. Both amplitude- and phase-shaping are studied. Model-based phase-shaping is implemented in a state-of-the-art fiber CPA-system. The influence of the polarization state is also highlighted. Additionally, existing techniques and recent advances are put into context. (orig.)

  18. Pulsed plasma arc cladding

    Institute of Scientific and Technical Information of China (English)

    龙; 白钢; 李振民; 张赋升; 杨思乾


    A prototype of Pulsed Plasma Arc Cladding system was developed, in which single power source supplies both transferred plasma arc (TPA) and non-transferred plasma arc (N-TPA). Both plasmas work in turn in a high frequency controlled by an IGBT connecting nozzle and workpiece. The working frequency of IGBT ranges from 50 ~ 7000Hz, in which the plasmas can work in turn smoothly. Higher than 500 Hz of working frequency is suggested for promotion of cladding quality and protection of IGBT. Drag phenomenon of TPA intensifies as the frequency goes up, which tends to increase the current proportion of TPA and suppress N-TPA. The occupation ratio of IGBT can be regulated from 5% ~ 95%, which balances the power supplies of both plasmas. An occupation ratio higher than 50% gives adequate proportion of arc current for N-TPA to preheat powder.

  19. Nanofabrication with Pulsed Lasers

    Directory of Open Access Journals (Sweden)

    Kabashin AV


    Full Text Available Abstract An overview of pulsed laser-assisted methods for nanofabrication, which are currently developed in our Institute (LP3, is presented. The methods compass a variety of possibilities for material nanostructuring offered by laser–matter interactions and imply either the nanostructuring of the laser-illuminated surface itself, as in cases of direct laser ablation or laser plasma-assisted treatment of semiconductors to form light-absorbing and light-emitting nano-architectures, as well as periodic nanoarrays, or laser-assisted production of nanoclusters and their controlled growth in gaseous or liquid medium to form nanostructured films or colloidal nanoparticles. Nanomaterials synthesized by laser-assisted methods have a variety of unique properties, not reproducible by any other route, and are of importance for photovoltaics, optoelectronics, biological sensing, imaging and therapeutics.

  20. Nanosecond Pulse Technique (United States)


    tunnel diodes, to ferrites, etc.) and to the need for the review of the methods of formation and converting the pulses, to a considerable degree...4n3l) 0 1 + 4n 21)2 + (4n2l) (.84) _ 4 nf tl 5 (I - 4n12/) 2 - (4nil)’ (1.85) " ( - 2o) l - 4’n2% 2 I3 (I + 4n =2/)2 + ( 41a2 )’ -arg + 4ni,21. + j4na,tJ...recirculator is borrowed from the article of Yu. I. Neymark, Yu. K. Maklakov and L. P. Yelkins [105]. ENDFOOTNOTE. DOC = 88076720 PAGE d a) t l I t S6) t�t

  1. Nanofabrication with pulsed lasers. (United States)

    Kabashin, Av; Delaporte, Ph; Pereira, A; Grojo, D; Torres, R; Sarnet, Th; Sentis, M


    An overview of pulsed laser-assisted methods for nanofabrication, which are currently developed in our Institute (LP3), is presented. The methods compass a variety of possibilities for material nanostructuring offered by laser-matter interactions and imply either the nanostructuring of the laser-illuminated surface itself, as in cases of direct laser ablation or laser plasma-assisted treatment of semiconductors to form light-absorbing and light-emitting nano-architectures, as well as periodic nanoarrays, or laser-assisted production of nanoclusters and their controlled growth in gaseous or liquid medium to form nanostructured films or colloidal nanoparticles. Nanomaterials synthesized by laser-assisted methods have a variety of unique properties, not reproducible by any other route, and are of importance for photovoltaics, optoelectronics, biological sensing, imaging and therapeutics.

  2. Pulsed plasma electron sourcesa) (United States)

    Krasik, Ya. E.; Yarmolich, D.; Gleizer, J. Z.; Vekselman, V.; Hadas, Y.; Gurovich, V. Tz.; Felsteiner, J.


    There is a continuous interest in research of electron sources which can be used for generation of uniform electron beams produced at E ≤105 V/cm and duration ≤10-5 s. In this review, several types of plasma electron sources will be considered, namely, passive (metal ceramic, velvet and carbon fiber with and without CsI coating, and multicapillary and multislot cathodes) and active (ferroelectric and hollow anodes) plasma sources. The operation of passive sources is governed by the formation of flashover plasma whose parameters depend on the amplitude and rise time of the accelerating electric field. In the case of ferroelectric and hollow-anode plasma sources the plasma parameters are controlled by the driving pulse and discharge current, respectively. Using different time- and space-resolved electrical, optical, spectroscopical, Thomson scattering and x-ray diagnostics, the parameters of the plasma and generated electron beam were characterized.

  3. Micro pulse lidar (United States)

    Spinhirne, James D.


    An eye safe, compact, solid state lidar for profiling atmospheric cloud and aerosol scattering has been demonstrated. The transmitter of the micropulse lidar is a diode pumped micro-J pulse energy, high repetition rate Nd:YLF laser. Eye safety is obtained through beam expansion. The receiver employs a photon counting solid state Geiger mode avalanche photodiode detector. Data acquisition is by a single card multichannel scaler. Daytime background induced quantum noise is controlled by a narrow receiver field-of-view and a narrow bandwidth temperature controlled interference filter. Dynamic range of the signal is limited by optical geometric signal compression. Signal simulations and initial atmospheric measurements indicate that systems built on the micropulse lidar concept are capable of detecting and profiling all significant cloud and aerosol scattering through the troposphere and into the stratosphere. The intended applications are scientific studies and environmental monitoring which require full time, unattended measurements of the cloud and aerosol height structure.

  4. Capacitor discharge pulse analysis.

    Energy Technology Data Exchange (ETDEWEB)

    Baker, Michael Sean; Griffiths, Stewart K.; Tanner, Danelle Mary


    Capacitors used in firing sets and other high discharge current applications are discharge tested to verify performance of the capacitor against the application requirements. Parameters such as capacitance, inductance, rise time, pulse width, peak current and current reversal must be verified to ensure that the capacitor will meet the application needs. This report summarizes an analysis performed on the discharge current data to extract these parameters by fitting a second-order system model to the discharge data and using this fit to determine the resulting performance metrics. Details of the theory and implementation are presented. Using the best-fit second-order system model to extract these metrics results in less sensitivity to noise in the measured data and allows for direct extraction of the total series resistance, inductance, and capacitance.

  5. Template Reproduction of GRB Pulse Light Curves (United States)

    Hakkila, Jon E.; Preece, R. D.; Loredo, T. J.; Wolpert, R. L.; Broadbent, M. E.


    A study of well-isolated pulses in gamma ray burst light curves indicates that simple models having smooth and monotonic pulse rises and decays are inadequate. Departures from the Norris et al. (2005) pulse shape are in the form of a wave-like pre-peak residual that is mirrored and stretched following the peak. Pulse shape departures are present in GRB pulses of all durations, but placement of the departures relative to pulse peaks correlates with asymmetry. This establishes an additional link between temporal structure and spectral evolution, as pulse asymmetry is related to initial hardness while pulse duration indicates the rate of hard-to-soft pulse evolution.

  6. Research agenda shrimp pulse fishery

    NARCIS (Netherlands)

    Marlen, van B.; Rasenberg, M.M.M.; Verschueren, B.; Polet, H.


    In the recent decennia, many developments have taken place to improve the selectivity of the shrimp fishing gears. Recently, the development of a pulse gear for catching shrimps has taken up again as an opportunity to decrease discards, inspired by developments in the flatfish pulse fishery.

  7. Pulse oximetry for perioperative monitoring

    DEFF Research Database (Denmark)

    Pedersen, Tom; Møller, Ann Merete; Hovhannisyan, Karen


    Pulse oximetry is extensively used in the perioperative period and might improve patient outcomes by enabling an early diagnosis and, consequently, correction of perioperative events that might cause postoperative complications or even death. Only a few randomized clinical trials of pulse oximetry...

  8. A Single-Pulse Integrator

    DEFF Research Database (Denmark)

    Miller, Arne


    A single-pulse integrator is described. It gives a relative measure of the integral of the output signal from a coil monitor on the Risø 10 MeV linear accelerator, and displays the value on a digital voltmeter. The reproduccibility is found to be better than ±1% for an accelerated pulse charge...

  9. NMR in pulsed magnetic field

    KAUST Repository

    Abou-Hamad, Edy


    Nuclear magnetic resonance (NMR) experiments in pulsed magnetic fields up to 30.4 T focused on 1H and 93Nb nuclei are reported. Here we discuss the advantage and limitation of pulsed field NMR and why this technique is able to become a promising research tool. © 2011 Elsevier Inc. All Rights Reserved.

  10. Dexamethasone pulse therapy in pemphigus

    NARCIS (Netherlands)

    Toth, GG; van de Meer, JB; Jonkman, MF


    Pulse therapy with high-dose glucocorticoids was introduced 20 years ago as a treatment modality for autoimmune disease and transplant rejection. The most popular dermatological indication for pulse therapy is severe pemphigus. We reviewed the sequelae of 14 patients with pemphigus who were treated

  11. Pulse oximetry for perioperative monitoring

    DEFF Research Database (Denmark)

    Pedersen, Tom; Nicholson, Amanda; Hovhannisyan, Karen


    . Results indicated that hypoxaemia was reduced in the pulse oximetry group, both in the operating theatre and in the recovery room. During observation in the recovery room, the incidence of hypoxaemia in the pulse oximetry group was 1.5 to three times less. Postoperative cognitive function was independent...... postoperative complications or even death. Only a few randomized clinical trials of pulse oximetry during anaesthesia and in the recovery room have been performed that describe perioperative hypoxaemic events, postoperative cardiopulmonary complications and cognitive dysfunction. OBJECTIVES: To study the use...... checked the reference lists of trials and review articles. The original search was performed in January 2005, and a previous update was performed in May 2009. SELECTION CRITERIA: We included all controlled trials that randomly assigned participants to pulse oximetry or no pulse oximetry during...

  12. Neurostimulation using subnanosecond electric pulses (United States)

    Xiao, Shu; Pakhomov, Andrei; Guo, Fei; Polisetty, Swetha; Schoenbach, Karl H.


    We have for the first time recorded action potentials in rat hippocampus neurons when they were stimulated by subnanosecond electric pulses. The preliminary results show that applying a series of pulses allowed the accumulation of depolarization before activating the voltage gated channels. The depolarization only occurred when the electric pulses were applied. It is unclear whether the depolarization is caused by the charge accumulation across the membrane or the cation influx due to the membrane permeabilization. We have also conducted an electromagnetic simulation of delivering subnanosecond pulses to tissues using an impulse radiating antenna. The results show that the pulses can be confined in the deep region in the brain but the amplitude is reduced significantly due to the attenuation of the tissues. A partially lossy dielectric lens may be used to reverse the decreasing trend of the electric field.

  13. Pre-earthquake Magnetic Pulses

    CERN Document Server

    Scoville, John; Freund, Friedemann


    A semiconductor model of rocks is shown to describe unipolar magnetic pulses, a phenomenon that has been observed prior to earthquakes. These pulses are observable because their extremely long wavelength allows them to pass through the Earth's crust. Interestingly, the source of these pulses may be triangulated to pinpoint locations where stress is building deep within the crust. We couple a semiconductor drift-diffusion model to a magnetic field in order to describe the electromagnetic effects associated with electrical currents flowing within rocks. The resulting system of equations is solved numerically and it is seen that a volume of rock may act as a diode that produces transient currents when it switches bias. These unidirectional currents are expected to produce transient unipolar magnetic pulses similar in form, amplitude, and duration to those observed before earthquakes, and this suggests that the pulses could be the result of geophysical semiconductor processes.

  14. Pulse shaping using a spatial light modulator

    CSIR Research Space (South Africa)

    Botha, N


    Full Text Available Femtosecond pulse shaping can be done by different kinds of pulse shapers, such as liquid crystal spatial light modulators (LC SLM), acousto optic modulators (AOM) and deformable and movable mirrors. A few applications where pulse shaping...

  15. Pulse source requirements for OTDM systems

    DEFF Research Database (Denmark)

    Clausen, Anders; Poulsen, Henrik Nørskov; Oxenløwe, Leif Katsuo


    A simulation model for investigating the impact of incoherent crosstalk due to pulse tail overlapping is proposed. Requirements to pulse width and pulse tail extinction ratio introducing a maximum of 1 dB penalty is extracted....

  16. An Eye Oximeter for Combat Casualty Care (United States)


    hemodilution in pigs. Chest 1992: 101:1121-1124. 12. Connors F. Speroff T, Dawson N, et al: The effectiveness of right heart catheterization in the...Med. 1992:10:538. 8. Hospital Inputient Charges. Baltimore, Md: Healthcare Knowledge Resources: 1993:238. 9. Connors F, Speroff T. Dawson N. et al...Baltimore, MD, 1993, pp 238-9. 9. Connors AF, Speroff T, Dawson N, et al. The effectiveness of right heart catheterization in the initial care of

  17. An Eye Oximeter for Combat Casualty Care (United States)


    81 4 Introduction Exsanguination is the most immediate life threatening danger for the field casualty during wartime. Indeed, 60% of...intramuscular pre- anesthetic ketamine 600 mg and xylazine 100 mg. The swine were placed in the supine position, intubated endotracheally and placed on a...preanesthetic ketamine 600 mg and xylazine 100 mg. The swine were placed Study Protocol. The animal was exsanguinated in the supine position, intubated

  18. Bomb pulse biology

    Energy Technology Data Exchange (ETDEWEB)

    Falso, Miranda J. Sarachine [Center for Accelerator Mass Spectrometry, Mail Stop L-397, Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, CA 94551 (United States); Buchholz, Bruce A., E-mail: [Center for Accelerator Mass Spectrometry, Mail Stop L-397, Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, CA 94551 (United States)


    The past decade has seen an explosion in use of the {sup 14}C bomb pulse to do fundamental cell biology. Studies in the 1960s used decay counting to measure tissue turnover when the atmospheric {sup 14}C/C concentration was changing rapidly. Today bulk tissue measurements are of marginal interest since most of the carbon in the tissue resides in proteins, lipids and carbohydrates that turn over rapidly. Specific cell types with specialized functions are the focus of cell turnover investigations. Tissue samples need to be fresh or frozen. Fixed or preserved samples contain petroleum-derived carbon that has not been successfully removed. Cell or nuclear surface markers are used to sort specific cell types, typically by fluorescence-activated cell sorting (FACS). Specific biomolecules need to be isolated with high purity and accelerator mass spectrometry (AMS) measurements must accommodate samples that generally contain less than 40 {mu}g of carbon. Furthermore, all separations must not add carbon to the sample. Independent means such as UV absorbance must be used to confirm molecule purity. Approaches for separating specific proteins and DNA and combating contamination of undesired molecules are described.

  19. Pulsed electron beam precharger

    Energy Technology Data Exchange (ETDEWEB)

    Finney, W.C. (ed.); Shelton, W.N.


    Electrostatic collection of a high resistivity aerosol using the Electron Beam Precipitator (EBP) collecting section was demonstrated during this reporting period (Quarter Five). Collection efficiency experiments were designed to confirm and extend some of the work performed under the previous contract. The reason for doing this was to attempt to improve upon the collection efficiency of the precipitator alone when testing with a very high resistivity, moderate-to-high concentration dust load. From the collector shakedown runs, a set of suitable operational parameters were determined for the downstream electrostatic collecting sections of the Electron Beam Precipitator wind tunnel. These parameters, along with those for the MINACC electron beam, will generally be held constant while the numerous precharging parameters are varied to produce an optimum particle charge. The electrostatic collector experiments were part of a larger, comprehensive investigation on electron beam precharging of high resistivity aerosol particles performed during the period covered by Quarters Five, Six, and Seven. This body of work used the same experimental apparatus and procedures and the experimental run period lasted nearly continuously for six months. A summary of the Quarter Five work is presented in the following paragraphs. Section II-A of TPR 5 contains a report on the continuing effort which was expended on the modification and upgrade of the pulsed power supply and the monitoring systems prior to the initiation of the electron beam precharging experimental work.

  20. Magnetic Alignment of Pulsed Solenoids Using the Pulsed Wire Method

    Energy Technology Data Exchange (ETDEWEB)

    Arbelaez, D.; Madur, A.; Lipton, T.M.; Waldron, W.L.; Kwan, J.W.


    A unique application of the pulsed-wire measurement method has been implemented for alignment of 2.5 T pulsed solenoid magnets. The magnetic axis measurement has been shown to have a resolution of better than 25 {micro}m. The accuracy of the technique allows for the identification of inherent field errors due to, for example, the winding layer transitions and the current leads. The alignment system is developed for the induction accelerator NDCX-II under construction at LBNL, an upgraded Neutralized Drift Compression experiment for research on warm dense matter and heavy ion fusion. Precise alignment is essential for NDCX-II, since the ion beam has a large energy spread associated with the rapid pulse compression such that misalignments lead to corkscrew deformation of the beam and reduced intensity at focus. The ability to align the magnetic axis of the pulsed solenoids to within 100 pm of the induction cell axis has been demonstrated.

  1. Causality effects on accelerating light pulses

    National Research Council Canada - National Science Library

    Kaminer, Ido; Lumer, Yaakov; Segev, Mordechai; Christodoulides, Demetrios N


    .... We explore the effects of causality, and find that, whereas decelerating pulses can asymptotically reach zero group velocity, pulses that accelerate towards infinite group velocity inevitably break...

  2. Pulsed ultrasonic stir welding method (United States)

    Ding, R. Jeffrey (Inventor)


    A method of performing ultrasonic stir welding uses a welding head assembly to include a plate and a rod passing through the plate. The rod is rotatable about a longitudinal axis thereof. In the method, the rod is rotated about its longitudinal axis during a welding operation. During the welding operation, a series of on-off ultrasonic pulses are applied to the rod such that they propagate parallel to the rod's longitudinal axis. At least a pulse rate associated with the on-off ultrasonic pulses is controlled.

  3. Hyper dispersion pulse compressor for chirped pulse amplification systems (United States)

    Barty, Christopher P. J.


    A grating pulse compressor configuration is introduced for increasing the optical dispersion for a given footprint and to make practical the application for chirped pulse amplification (CPA) to quasi-narrow bandwidth materials, such as Nd:YAG. The grating configurations often use cascaded pairs of gratings to increase angular dispersion an order of magnitude or more. Increased angular dispersion allows for decreased grating separation and a smaller compressor footprint.

  4. Admittance plethysmographic evaluation of undulatory massage for the edematous limb. (United States)

    Yamazaki, Z; Fujimori, Y; Wada, T; Togawa, T; Yamakoshi, K; Shimazu, H


    A new apparatus, called Hadomer has been developed for the treatment of peripheral lymphedema and venous disorder. It has cuffs with 5 rooms, through which the air pressure moves from periphery to proximal point, just like surging waves. The peripheral stagnant lymph and venous blood are displaced toward the heart by this pneumatic massage. Hadomer has been applied to more than 400 patients with the edematous limbs, with satisfactory results, such as decrease of swelling, pain and induration. These clinical results have been also confirmed by electrical admittance plethysmography which is useful to measure noninvasively the edematous volume and the blood flow. The admittance of the edematous limbs is high and after massaging with Hadomer it approaches normal range. The blood flow in the diseased limbs is less than the healthy one and it is observed better after pneumatically massaging.

  5. Pulse-to-pulse Diagnostics at High Reprate (United States)

    Green, Bertram; Kovalev, Sergey; Golz, Torsten; Stojanovich, Nikola; Fisher, Alan; Kampfrath, Tobias; Gensch, Michael


    Femtosecond level diagnostic and control of sub-picosecond electron bunches is an important topic in modern accelerator research. At the same time new linear electron accelerators based on quasi-CW SRF technology will be the drivers of many future 4th Generation lightsources such as X-ray free electron lasers. A high duty cycle, high stability and online pulse to pulse diagnostic at these new accelerators are crucial ingredients to the success of these large scale facilities. A novel THz based online monitor concept is presented that has the potential to give access to pulse to pulse information on bunch form, arrival time and energy at high repetition rate and down to sub pC charges. We furthermore show experimentally that pulse to pulse arrival time measurements can be used to perform pump-probe experiments with a temporal resolution in the few-fs regime and an exceptional dynamic range. Our scheme has been tested at the superradiant test facility TELBE, but can be readily transferred to other SRF accelerator driven photon sources, such as X-FELs.

  6. Pulsed light and pulsed electric field for foods and eggs. (United States)

    Dunn, J


    Two new technologies for use in the food industry are described. The first method discussed uses intense pulse of light. This pulsed light (PureBright) process uses short duration flashes of broad spectrum "white" light to kill all exposed microorganisms, including vegetative bacteria, microbial and fungal spores, viruses, and protozoan oocysts. Each pulse, or flash, of light lasts only a few hundred millionths of a second (i.e., a few hundred microseconds). The intensity of each flash of light is about 20,000 times the intensity of sunlight at the earth's surface. The flashes are typically applied at a rate of about one to tens of flashes per second. For most applications, a few flashes applied in a fraction of a second provide an effective treatment. High microbial kill can be achieved, for example, on the surfaces of packaging materials, on packaging and processing equipment, foods, and medical devices as well as on many other surfaces. In addition, some bulk materials such as water and air that allow penetration of the light can be sterilized. The results of tests to measure the effects of pulsed light on Salmonella enteritiditis on eggs are presented. The second method discussed uses multiple, short duration, high intensity electric field pulses to kill vegetative microorganisms in pumpable products. This pulsed electric field (or CoolPure) process can be applied at modest temperatures at which no appreciable thermal damage occurs and the original taste, color, texture, and functionality of products can be retained.

  7. Treatment of Persistent Facial Postinflammatory Hyperpigmentation With Novel Pulse-in-Pulse Mode Intense Pulsed Light. (United States)

    Park, Ji-Hye; Kim, Jung-In; Kim, Won-Serk


    Postinflammatory hyperpigmentation (PIH) is an acquired hypermelanosis induced by various causes including inflammatory dermatoses, injury, or cosmetic procedures, such as lasers or chemical peels, and it tends to affect dark-skinned people with greater frequency and severity. There are a variety of treatment options for PIH, including topical agents, chemical peels, laser, and light therapy. However, the results are not up to expectation. The purpose of this study was to examine the clinical efficacy and safety of novel pulse-in-pulse mode intense pulsed light (IPL) for the treatment of persistent facial PIH in Korean patients. Twenty-five Korean female patients (Fitzpatrick skin types III-V) with persistent facial PIH were enrolled in the study. The patients were treated with novel pulse-in-pulse mode IPL for 4 sessions at 1-week interval and 4 sessions at 2-week intervals. Treatment efficacy and patient satisfaction were evaluated using photographs and questionnaires. After 2 months of all treatments, 23 patients (92%) had more than 50% improvement and 22 patients (88%) were satisfied with the treatments. No adverse effects or aggravations were reported. The pulse-in-pulse mode IPL treatment is effective and safe for persistent facial PIH in dark-skinned patients.

  8. Intense pulsed neutron source (United States)

    The IPNS Progress Report 10th Anniversary Edition is being published in recognition of the first ten years of successful IPNS operation. To emphasize the significance of this milestone, we wanted this report to stand apart from the previous IPNS Progress Reports, and the best way to do this, we thought, was to make the design and organization of the report significantly different. In their articles, authors were asked to emphasize not only advances made since IPNS began operating but also the groundwork that was laid at its predecessor facilities - Argonne's ZING-P and ZING-P' prototype pulsed neutron sources and CP-5 reactor. Each article stands as a separate chapter in the report, since each represents a particular instrument or class of instruments, system, technique, or area of research. In some cases, contributions were similar to review articles in scientific journals, complete with extensive lists of references. Ten-year cumulative lists of members of IPNS committees and of scientists who have visited or done experiments at IPNS were assembled. A list of published and 'in press' articles in journals, books, and conference proceedings, resulting from work done at IPNS during the past ten years, was compiled. And archival photographs of people and activities during the ten-year history of IPNS were located and were used liberally throughout the report. The titles of the chapters in this report are: accelerator; computer; radiation effects; powder; stress; single crystal; superconductivity; amorphous; small angle; reflection; quasielastic; inelastic; inelastic magnetic; deep inelastic; user program; the future; and publications.

  9. Next generation Chirped Pulse Amplification

    Energy Technology Data Exchange (ETDEWEB)

    Nees, J.; Biswal, S.; Mourou, G. [Univ. Michigan, Center for Ultrafast Optical Science, Ann Arbor, MI (United States); Nishimura, Akihiko; Takuma, Hiroshi


    The limiting factors of Chirped Pulse Amplification (CPA) are discussed and experimental results of CPA in Yb:glass regenerative amplifier are given. Scaling of Yb:glass to the petawatt level is briefly discussed. (author)

  10. Rapidly pulsed helium droplet source

    Energy Technology Data Exchange (ETDEWEB)

    Pentlehner, Dominik; Riechers, Ricarda; Dick, Bernhard; Slenczka, Alkwin [Institute for Physical and Theoretical Chemistry, University of Regensburg, 93053 Regensburg (Germany); Even, Uzi; Lavie, Nachum; Brown, Raviv; Luria, Kfir [Sackler Faculty of Exact Sciences, School of Chemistry, Tel Aviv University, Ramat Aviv, 69978 Tel Aviv (Israel)


    A pulsed valve connected to a closed-cycle cryostat was optimized for producing helium droplets. The pulsed droplet beam appeared with a bimodal size distribution. The leading part of the pulse consists of droplets suitable for doping with molecules. The average size of this part can be varied between 10{sup 4} and 10{sup 6} helium atoms, and the width of the distribution is smaller as compared to a continuous-flow droplet source. The system has been tested in a single pulse mode and at repetition rates of up to 500 Hz with almost constant intensity. The droplet density was found to be increased by more than an order of magnitude as compared to a continuous-flow droplet source.

  11. Low-noise pulse conditioner (United States)

    Bird, D.A.


    A low-noise pulse conditioner is provided for driving electronic digital processing circuitry directly from differentially induced input pulses. The circuit uses a unique differential-to-peak detector circuit to generate a dynamic reference signal proportional to the input peak voltage. The input pulses are compared with the reference signal in an input network which operates in full differential mode with only a passive input filter. This reduces the introduction of circuit-induced noise, or jitter, generated in ground referenced input elements normally used in pulse conditioning circuits, especially speed transducer processing circuits. This circuit may be used for conditioning the sensor signal from the Fidler coil in a gas centrifuge for separation of isotopic gaseous mixtures.

  12. Pulse tube refrigerator; Parusukan reitoki

    Energy Technology Data Exchange (ETDEWEB)

    Hozumi, Yoshikazu [University of Tsukuba, Tsukuba (Japan); Shiraishi, Masao [Hiroshima University, Hiroshima (Japan)


    In the cryogenic field, high temperature superconductivity and research and development of the peripheral technology are popular. Refrigerating machine development of the very low temperature is also one of the results. Research and development are mainly advanced as a refrigerating machine of the center for the aerospace plane installation. There is special and small very low temperature refrigerating machine called 'the pulse tube refrigerating machine' of which the practical application is also recently being attempted for the semiconductor cooling using high temperature superconductivity. At present, the basic research of elucidation of refrigeration phenomenon of pulse tube refrigerating machine and development of high-performance pulse tube refrigerating machine is carried out by experiment in the Ministry of International Trade and Industry Mechanical Engineering Lab., Agency of Industrial Sci. and Technology and numerical simulation in Chiyoda Corp. In this report, the pulse tube refrigerating machine is introduced, and the application in the chemical engineering field is considered. (NEDO)

  13. Pulsed ultrasonic stir welding system (United States)

    Ding, R. Jeffrey (Inventor)


    An ultrasonic stir welding system includes a welding head assembly having a plate and a rod passing through the plate. The rod is rotatable about a longitudinal axis thereof. During a welding operation, ultrasonic pulses are applied to the rod as it rotates about its longitudinal axis. The ultrasonic pulses are applied in such a way that they propagate parallel to the longitudinal axis of the rod.

  14. Optical pulses, lasers, measuring techniques

    CERN Document Server

    Früngel, Frank B A


    High Speed Pulse Technology: Volume II: Optical Pulses - Lasers - Measuring Techniques focuses on the theoretical and engineering problems that result from the capacitor discharge technique.This book is organized into three main topics: light flash production from a capacitive energy storage; signal transmission and ranging systems by capacitor discharges and lasers; and impulse measuring technique. This text specifically discusses the air spark under atmospheric conditions, industrial equipment for laser flashing, and claims for light transmitting system. The application of light impulse sign

  15. Pulsed feedback defers cellular differentiation.

    Directory of Open Access Journals (Sweden)

    Joe H Levine


    Full Text Available Environmental signals induce diverse cellular differentiation programs. In certain systems, cells defer differentiation for extended time periods after the signal appears, proliferating through multiple rounds of cell division before committing to a new fate. How can cells set a deferral time much longer than the cell cycle? Here we study Bacillus subtilis cells that respond to sudden nutrient limitation with multiple rounds of growth and division before differentiating into spores. A well-characterized genetic circuit controls the concentration and phosphorylation of the master regulator Spo0A, which rises to a critical concentration to initiate sporulation. However, it remains unclear how this circuit enables cells to defer sporulation for multiple cell cycles. Using quantitative time-lapse fluorescence microscopy of Spo0A dynamics in individual cells, we observed pulses of Spo0A phosphorylation at a characteristic cell cycle phase. Pulse amplitudes grew systematically and cell-autonomously over multiple cell cycles leading up to sporulation. This pulse growth required a key positive feedback loop involving the sporulation kinases, without which the deferral of sporulation became ultrasensitive to kinase expression. Thus, deferral is controlled by a pulsed positive feedback loop in which kinase expression is activated by pulses of Spo0A phosphorylation. This pulsed positive feedback architecture provides a more robust mechanism for setting deferral times than constitutive kinase expression. Finally, using mathematical modeling, we show how pulsing and time delays together enable "polyphasic" positive feedback, in which different parts of a feedback loop are active at different times. Polyphasic feedback can enable more accurate tuning of long deferral times. Together, these results suggest that Bacillus subtilis uses a pulsed positive feedback loop to implement a "timer" that operates over timescales much longer than a cell cycle.

  16. Artistic Representation with Pulsed Holography (United States)

    Ishii, S.


    This thesis describes artistic representation through pulsed holography. One of the prevalent practical problems in making holograms is object movement. Any movement of the object or film, including movement caused by acoustic vibration, has the same fatal results. One way of reducing the chance of movement is by ensuring that the exposure is very quick; using a pulsed laser can fulfill this objective. The attractiveness of using pulsed laser is based on the variety of materials or objects that can be recorded (e.g., liquid material or instantaneous scene of a moving object). One of the most interesting points about pulsed holograms is that some reconstructed images present us with completely different views of the real world. For example, the holographic image of liquid material does not appear fluid; it looks like a piece of hard glass that would produce a sharp sound upon tapping. In everyday life, we are unfamiliar with such an instantaneous scene. On the other hand, soft-textured materials such as a feather or wool differ from liquids when observed through holography. Using a pulsed hologram, we can sense the soft touch of the object or material with the help of realistic three-dimensional (3-D) images. The images allow us to realize the sense of touch in a way that resembles touching real objects. I had the opportunity to use a pulsed ruby laser soon after I started to work in the field of holography in 1979. Since then, I have made pulsed holograms of activities, including pouring water, breaking eggs, blowing soap bubbles, and scattering feathers and popcorn. I have also created holographic art with materials and objects, such as silk fiber, fabric, balloons, glass, flowers, and even the human body. Whenever I create art, I like to present the spectator with a new experience in perception. Therefore, I would like to introduce my experimental artwork through those pulsed holograms.

  17. High Voltage Pulse Testing Survey. (United States)


    Cryogenic 23 E. Liquids 26 F. Solids 28 1. Polyethylene 28 2. Cross-Linked Polyethylene ( XLPE ) 29 3. Polyimide and Polyvenylchloride (PVC) 31 VI Benefits 35 A...Strength of XLPE Cables 29 vii * 4" I PROGRAM OBJECTIVES The Pulse Test Survey summarizes government, industry, and technical reports on high voltage pulse...system of silicone oil on a XLPE (cross-linked polyethylene) spacer tends to lower the impulse breakdown by approximately 10 percent. The negative impulse

  18. Development of Pulse Oxygen Saturation Measurement System Based on FPGA%基于FPGA的脉搏血氧饱和度检测系统设计

    Institute of Scientific and Technical Information of China (English)

    游海峰; 谢勤岚


    Oxygen saturation is an important parameter to measure human blood oxygen carrying capacity, and also an important physiological indexes in the common clinical diagnosis and family care. Based on the infrared spectrum method in blood oxygen saturation measurement, a pulse oxygen aturation measurement system is designed. The system which consists of the FPGA platform, the RSJ048CAS finger chip pulse oximeter sensor, control and display module, can monitor the oxygen saturation timely, continuously and non-invasively. The experimental results show that in a quiet state the system can realize the measurement of the oxygen saturation not less than 94%.%血氧饱和度是衡量人体血液携带氧能力的重要参数,也是临床诊断和家庭保健中重要的生理指标.根据红外光谱法血氧饱和度测量原理,设计了一种血氧饱和度测量系统.系统以FPGA为开发平台,包括RSJ048CAS指夹式脉搏血氧探头、AD采集模块、信号调理模块、控制显示模块等模块,它可以实时、连续和无创地进行血氧饱和度检测.实验结果表明,在安静状态下,该系统可实现测得的血氧饱和度不低于94%.

  19. Millijoule pulse energy picosecond fiber chirped-pulse amplification system

    Institute of Scientific and Technical Information of China (English)

    Zhi Yang; Xiaohong Hu; Yishan Wang; Wei Zhang; Wei Zhao


    @@ The efficient generation of a 1.17-mJ laser pul8e with 360 ps duration using an ytterbium (Yb)-doped fiber amplifier chain seeded by a homemade mode-locked fiber laser is demonstrated experimentally.A specially designed figure-of-eight fiber laser acts as the seed source of a chirped-pulse amplification (CPA) system and generates mode-locked pulse8 with hundreds of picosecond widths.Two kinds of large-mode-area (LMA) double-clad Yb-doped fibers are employed to construct the pre-amplifier and main amplifier, All of the adopted instruments help avoid severe nonlinearity in fibers to raise sub-nanosecond pulse energy with acceptable signal-to-noise ratio (SNR).The output spectrum of this fiber-based CPA system shows that amplified spontaneous emission (ASE) is suppressed to better than 30 dB, and the onset of stimulated Raman scattering is excluded.%The efficient generation of a 1.17-mJ laser pulse with 360 ps duration using an ytterbium (Yb)-doped fiber amplifier chain seeded by a homemade mode-locked fiber laser is demonstrated experimentally. A specially designed figure-of-eight fiber laser acts as the seed source of a chirped-pulse amplification (CPA) system and generates mode-locked pulses with hundreds of picosecond widths. Two kinds of large-mode-area (LMA) double-clad Yb-doped fibers are employed to construct the pre-amplifier and main amplifier. All of the adopted instruments help avoid severe nonlinearity in fibers to raise sub-nanosecond pulse energy with acceptable signal-to-noise ratio (SNR). The output spectrum of this fiber-based CPA system shows that amplified spontaneous emission (ASE) is suppressed to better than 30 dB, and the onset of stimulated Raman scattering is excluded.

  20. Square pulse linear transformer driver

    Directory of Open Access Journals (Sweden)

    A. A. Kim


    Full Text Available The linear transformer driver (LTD technological approach can result in relatively compact devices that can deliver fast, high current, and high-voltage pulses straight out of the LTD cavity without any complicated pulse forming and pulse compression network. Through multistage inductively insulated voltage adders, the output pulse, increased in voltage amplitude, can be applied directly to the load. The usual LTD architecture [A. A. Kim, M. G. Mazarakis, V. A. Sinebryukhov, B. M. Kovalchuk, V. A. Vizir, S. N Volkov, F. Bayol, A. N. Bastrikov, V. G. Durakov, S. V. Frolov, V. M. Alexeenko, D. H. McDaniel, W. E. Fowler, K. LeCheen, C. Olson, W. A. Stygar, K. W. Struve, J. Porter, and R. M. Gilgenbach, Phys. Rev. ST Accel. Beams 12, 050402 (2009PRABFM1098-440210.1103/PhysRevSTAB.12.050402; M. G. Mazarakis, W. E. Fowler, A. A. Kim, V. A. Sinebryukhov, S. T. Rogowski, R. A. Sharpe, D. H. McDaniel, C. L. Olson, J. L. Porter, K. W. Struve, W. A. Stygar, and J. R. Woodworth, Phys. Rev. ST Accel. Beams 12, 050401 (2009PRABFM1098-440210.1103/PhysRevSTAB.12.050401] provides sine shaped output pulses that may not be well suited for some applications like z-pinch drivers, flash radiography, high power microwaves, etc. A more suitable power pulse would have a flat or trapezoidal (rising or falling top. In this paper, we present the design and first test results of an LTD cavity that generates such a type of output pulse by including within its circular array a number of third harmonic bricks in addition to the main bricks. A voltage adder made out of a square pulse cavity linear array will produce the same shape output pulses provided that the timing of each cavity is synchronized with the propagation of the electromagnetic pulse.

  1. High-Altitude Electromagnetic Pulse (HEMP) Testing (United States)


    Electromagnetic Pulse Horizontal Electromagnetic Pulse Advanced Fast Electromagnetic Pulse Nuclear Weapons Effect Testing and Environments 16. SECURITY...TOP 01-2-620A 9 July 2015 G-1 APPENDIX G. ABBREVIATIONS. AFEMP Advanced Fast Electromagnetic ... Electromagnetic Pulse A burst of electromagnetic radiation from a nuclear explosion or a suddenly fluctuating magnetic field. The resulting electric and

  2. Intense ultrashort terahertz pulses: generation and applications

    Energy Technology Data Exchange (ETDEWEB)

    Hoffmann, Matthias C [Max Planck Research Department for Structural Dynamics, University of Hamburg, CFEL, 22607 Hamburg (Germany); Fueloep, Jozsef Andras, E-mail:, E-mail: [Department of Experimental Physics, University of Pecs, Ifjusag u. 6, 7624 Pecs (Hungary)


    Ultrashort terahertz pulses derived from femtosecond table-top sources have become a valuable tool for time-resolved spectroscopy during the last two decades. Until recently, the pulse energies and field strengths of these pulses have been generally too low to allow for the use as pump pulses or the study of nonlinear effects in the terahertz range. In this review article we will describe methods of generation of intense single cycle terahertz pulses with emphasis on optical rectification using the tilted-pulse-front pumping technique. We will also discuss some applications of these intense pulses in the emerging field of nonlinear terahertz spectroscopy. (topical review)

  3. Pulse compression and prepulse suppression apparatus (United States)

    Dane, C.B.; Hackel, L.A.; George, E.V.; Miller, J.L.; Krupke, W.F.


    A pulse compression and prepulse suppression apparatus (10) for time compressing the output of a laser (14). A pump pulse (46) is separated from a seed pulse (48) by a first polarized beam splitter (20) according to the orientation of a half wave plate (18). The seed pulse (48) is directed into an SBS oscillator (44) by two plane mirrors (22, 26) and a corner mirror (24), the corner mirror (24) being movable to adjust timing. The pump pulse (46) is directed into an SBS amplifier 34 wherein SBS occurs. The seed pulse (48), having been propagated from the SBS oscillator (44), is then directed through the SBS amplifier (34) wherein it sweeps the energy of the pump pulse (46) out of the SBS amplifier (34) and is simultaneously compressed, and the time compressed pump pulse (46) is emitted as a pulse output (52). A second polarized beam splitter (38) directs any undepleted pump pulse 58 away from the SBS oscillator (44).

  4. Consecutive Bright Pulses in the Vela Pulsar

    CERN Document Server

    Palfreyman, Jim L; Dickey, John M; Young, Timothy G; Hotan, Claire E; 10.1088/2041-8205/735/1/L17


    We report on the discovery of consecutive bright radio pulses from the Vela pulsar, a new phenomenon that may lead to a greater understanding of the pulsar emission mechanism. This results from a total of 345 hr worth of observations of the Vela pulsar using the University of Tasmania's 26 m radio telescope to study the frequency and statistics of abnormally bright pulses and sub-pulses. The bright pulses show a tendency to appear consecutively. The observations found two groups of six consecutive bright pulses and many groups of two to five bright pulses in a row. The strong radio emission process that produces the six bright pulses lasts between 0.4 and 0.6 s. The numbers of bright pulses in sequence far exceed what would be expected if individual bright pulses were independent random events. Consecutive bright pulses must be generated by an emission process that is long lived relative to the rotation period of the neutron star.

  5. 指甲油对不同品牌监测仪测定健康志愿者脉搏血氧饱和度的影响%Effects of nail polish on measurement of pulse oxygen saturation by different brands of monitors in healthy volunteers

    Institute of Scientific and Technical Information of China (English)

    陈洁; 徐鑫; 汪小海; 马正良; 顾小萍; 吉文亮


    (SpO2) by different brands of monitors in healthy volunteers.Methods Twenty healthy female volunteers were enrolled in the study.Nine fingers of each volunteer were chosen randomly,8 nails were painted 8 different colors (transparent color,red,yellow,green,blue,purple,black,white),respectively,and the left 1 nail served as blank control.SpO2 and pulse rate (PR) were measured using TuffSat Handheld Oximeter (GE) and MP70 (Philip) and PM-9800 (Mindray) monitors.SpO2 of the 9 nails monitored and the response time for SpO2 and PR were recorded.Results (1) Compared with blank control,when MP70 monitor was used,no significant change was found in each color-induced effect on the value of SpO2 obtained (P > 0.05),and blue prolonged the response time for PR and SpO2 (P < 0.05) ;When PM-9800 monitor was used,black could decrease the value of SpO2 measured (P < 0.05),and no significant change was found in each color-induced effect on the response time for SpO2 and PR (P > 0.05) ; when TuffSat Handheld Oximeter was used,green and blue could decrease the value of SpO2 monitored,and the value of SpO2 obtained was significantly lower when blue was used (P < 0.05).Black,blue,purple and white could sequentially prolong the response time for PR (P < 0.05),and no significant change was found in each color-induced effect on the response time for SpO2 (P > 0.05).(2) For green and blue nail polish,the value of SpO2 measured with TuffSat Handheld Oximeter was significantly lower than that measured with MP70 and PM-9800 monitors(P < 0.05) ; for red,yellow and green nail polish,the response time for PR obtained with TuffSat Handheld Oximeter was significantly shorter than that obtained with MP70 and PM-9800 monitors (P <0.05) ; for blank control group and 8 colors of nail polish,the response time for SpO2 measured with TuffSat Handheld Oximeter was significantly shorter than that measured with MP70 and PM-9800 monitors (P < 0.05).For black nail polish,the value of SpO2

  6. High-voltage, short-risetime pulse generator based on a ferrite pulse sharpener

    Energy Technology Data Exchange (ETDEWEB)

    Seddon, N.; Thornton, E.


    A high-voltage, short-risetime pulse generator is described. The generator consists of a Marx bank, which produces an initial high-voltage pulse, and a ferrite pulse sharpener that reduces the risetime of the pulse. The generator delivers 70-kV, 350-ps risetime pulses into a 50-..cap omega.. load.

  7. The coherent artifact in modern pulse measurements

    CERN Document Server

    Ratner, Justin; Wong, Tsz Chun; Bartels, Randy; Trebino, Rick


    We simulate multi-shot intensity-and-phase measurements of unstable ultrashort-pulse trains using frequency-resolved-optical-gating (FROG) and spectral phase interferometry for direct electric-field reconstruction (SPIDER). Both techniques fail to reveal the pulse structure. FROG yields the average pulse duration and suggests the instability by exhibiting disagreement between measured and retrieved traces. SPIDER under-estimates the average pulse duration but retrieves the correct average pulse spectral phase. An analytical calculation confirms this behavior.

  8. Wide Range SET Pulse Measurement (United States)

    Shuler, Robert L.; Chen, Li


    A method for measuring a wide range of SET pulses is demonstrated. Use of dynamic logic, faster than ordinary CMOS, allows capture of short pulses. A weighted binning of SET lengths allows measurement of a wide range of pulse lengths with compact circuitry. A pulse-length-conservative pulse combiner tree routes SETs from combinational logic to the measurement circuit, allowing SET measurements in circuits that cannot easily be arranged in long chains. The method is applied to add-multiplex combinational logic, and to an array of NFET routing switches, at .35 micron. Pulses are captured in a chain of Domino Logic AND gates. Propagation through the chain is frozen on the trailing edge by dropping low the second "enable" input to the AND gates. Capacitive loading is increased in the latter stages to create an approximately logarithmic weighted binning, so that a broad range of pulse lengths can be captured with a 10 stage capture chain. Simulations show pulses can be captured which are 1/5th the length of those typically captured with leading edge triggered latch methods, and less than the length of those captured with a trailing edge latch method. After capture, the pulse pattern is transferred to an SEU protected shift register for readout. 64 instances of each of two types of logic are used as targets. One is a full adder with a 4 to 1 mux on its inputs. The other is a 4 x 4 NFET routing matrix. The outputs are passed through buffered XNOR comparators to identify pulses, which are merged in a buffered not-nand (OR) tree designed to avoid pulse absorption as much as possible. The output from each of the two test circuits are input into separate pulse measurement circuits. Test inputs were provided so that the circuit could be bench tested and calibrated. A third SET measurement circuit with no inputs was used to judge the contribution from direct hits on the measurement circuit. Heavy ions were used with an LET range from 12 to 176. At LET of 21 and below, the very

  9. The pulsing CPSD method for subcritical assemblies with pulsed sources

    CERN Document Server

    Ballester, D; Ballester, Daniel; Munoz-Cobo, Jose L.


    Stochastic neutron transport theory is applied to the derivation of the two-neutron-detectors cross power spectral density for subcritical assemblies when external pulsed sources are used. A general relationship between the two-detector probability generating functions of the kernel and the source is obtained considering the contribution to detectors statistics of both the pulsed source and the intrinsic neutron source. An expansion in alpha-eigenvalues is derived for the final solution, which permits to take into account the effect of higher harmonics in subcritical systems. Further, expressions corresponding to the fundamental mode approximation are compared with recent results from experiments performed under the MUSE-4 European research project.

  10. High field rf superconductivity: to pulse or not to pulse

    Energy Technology Data Exchange (ETDEWEB)

    Campisi, I.E.


    Experimental data on the behavior of superconductors under the application of rf fields of amplitude comparable to their critical fields are sporadic and not always consistent. In many cases the field level at which breakdown in superconducting rf cavities should be expected has not been clearly established. Tests conducted with very short (approx. 1 rf pulses indicate that in this mode of operation fields close to the critical values can be consistently reached in superconducting cavities without breakdown. The advantages and disadvantages of the pulsed method are discussed compared to those of the more standard continuous wave (cw) systems. 60 references.

  11. Development of pulsed positron beam line with compact pulsing system

    Energy Technology Data Exchange (ETDEWEB)

    Maekawa, Masaki, E-mail: [Advanced Science Research Center, Japan Atomic Energy Agency, 1233 Watanuki, Takasaki, Gunma 370-1292 (Japan); Kawasuso, Atsuo [Advanced Science Research Center, Japan Atomic Energy Agency, 1233 Watanuki, Takasaki, Gunma 370-1292 (Japan)


    We have developed a pulsed slow positron beam with a pulse width of less than 200 ps and a period of 25 ns. The beam apparatus is composed of a Munich-type pre-buncher, a chopper and a buncher. Instead of the conventional RF cavity, a simple double-cylinder electrode is used for the buncher. The beam will be used for positron lifetime measurements. The time resolution of the whole system including lifetime measurement circuits is 250 ps, which is adequate for studying semiconductors and metals.

  12. Pre-earthquake magnetic pulses

    Directory of Open Access Journals (Sweden)

    J. Scoville


    Full Text Available A semiconductor model of rocks is shown to describe unipolar magnetic pulses, a phenomenon that has been observed prior to earthquakes. These pulses are generated deep in the Earth's crust, in and around the Hypocentral volume, days or even weeks before Earthquakes. They are observable at the surface because their extremely long wavelength allows them to pass through kilometers of rock. Interestingly, the source of these pulses may be triangulated to pinpoint locations where stresses are building deep within the crust. We couple a semiconductor drift-diffusion model to a magnetic field in order to describe the electromagnetic effects associated with electrical currents flowing within rocks. The resulting system of equations is solved numerically and it is seen that a volume of rock may act as a diode that produces transient currents when it switches bias. These unidirectional currents are expected to produce transient unipolar magnetic pulses similar in form, amplitude, and duration to those observed before earthquakes, and this suggests that the pulses could be the result of geophysical semiconductor processes.

  13. Pulsed discharge production Ar* metastables (United States)

    Han, Jiande; Heaven, Michael C.; Emmons, Daniel; Perram, Glen P.; Weeks, David E.; Bailey, William F.


    The production of relatively high densities of Ar* metastables (>1012 cm-3) in Ar/He mixtures, at total pressures close to 1 atm, is essential for the efficient operation of an optically pumped Ar* laser. We have used emission spectroscopy and diode laser absorption spectroscopy measurements to observe the production and decay of Ar* in a parallel plate pulsed discharge. With discharge pulses of 1 μs duration we find that metastable production is dominated by processes occurring within the first 100 ns of the gas break-down. Application of multiple, closely spaced discharge pulses yields insights concerning conditions that favor metastable production. This information has been combined with time-resolved measurements of voltage and current. The experimental results and preliminary modeling of the discharge kinetics are presented.

  14. Zeptosecond $\\gamma$-ray pulses

    CERN Document Server

    Klaiber, Michael; Keitel, Christoph H


    High-order harmonic generation (HHG) in the relativistic regime is employed to obtain zeptosecond pulses of $\\gamma$-rays. The harmonics are generated from atomic systems in counterpropagating strong attosecond laser pulse trains of linear polarization. In this setup recollisions of the ionized electrons can be achieved in the highly relativistic regime via a reversal of the commonly deteriorating drift and without instability of the electron dynamics such as in a standing laser wave. As a result, coherent attosecond $\\gamma$-rays in the 10 MeV energy range as well as coherent zeptosecond $\\gamma$-ray pulses of MeV photon energy for time-resolved nuclear spectroscopy become feasible.

  15. Dynamic parabolic pulse generation using temporal shaping of wavelength to time mapped pulses. (United States)

    Nguyen, Dat; Piracha, Mohammad Umar; Mandridis, Dimitrios; Delfyett, Peter J


    Self-phase modulation in fiber amplifiers can significantly degrade the quality of compressed pulses in chirped pulse amplification systems. Parabolic pulses with linear frequency chirp are suitable for suppressing nonlinearities, and to achieve high peak power pulses after compression. In this paper, we present an active time domain technique to generate parabolic pulses for chirped pulse amplification applications. Pulses from a mode-locked laser are temporally stretched and launched into an amplitude modulator, where the drive voltage is designed using the spectral shape of the input pulse and the transfer function of the modulator, resulting in the generation of parabolic pulses. Experimental results of pulse shaping with a pulse train from a mode-locked laser are presented, with a residual error of less than 5%. Moreover, an extinction ratio of 27 dB is achieved, which is ideal for chirped pulse amplification applications.

  16. Liquid micro pulsed plasma thruster

    Directory of Open Access Journals (Sweden)

    Szelecka Agnieszka


    Full Text Available A new type of pulsed plasma thruster (PPT for small satellite propulsion is investigated, of which the most innovative aspect is the use of a non-volatile liquid propellant. The thruster is based on an open capillary design. The thruster achieved a thrust-to-power ratio above 45 μN/W, which constitutes a 5-fold improvement over the water-propelled pulsed plasma thruster, and which is also slightly above the performance of a similarly sized PPT with a solid propellant.

  17. Pulse compressor with aberration correction

    Energy Technology Data Exchange (ETDEWEB)

    Mankos, Marian [Electron Optica, Inc., Palo Alto, CA (United States)


    In this SBIR project, Electron Optica, Inc. (EOI) is developing an electron mirror-based pulse compressor attachment to new and retrofitted dynamic transmission electron microscopes (DTEMs) and ultrafast electron diffraction (UED) cameras for improving the temporal resolution of these instruments from the characteristic range of a few picoseconds to a few nanoseconds and beyond, into the sub-100 femtosecond range. The improvement will enable electron microscopes and diffraction cameras to better resolve the dynamics of reactions in the areas of solid state physics, chemistry, and biology. EOI’s pulse compressor technology utilizes the combination of electron mirror optics and a magnetic beam separator to compress the electron pulse. The design exploits the symmetry inherent in reversing the electron trajectory in the mirror in order to compress the temporally broadened beam. This system also simultaneously corrects the chromatic and spherical aberration of the objective lens for improved spatial resolution. This correction will be found valuable as the source size is reduced with laser-triggered point source emitters. With such emitters, it might be possible to significantly reduce the illuminated area and carry out ultrafast diffraction experiments from small regions of the sample, e.g. from individual grains or nanoparticles. During phase I, EOI drafted a set of candidate pulse compressor architectures and evaluated the trade-offs between temporal resolution and electron bunch size to achieve the optimum design for two particular applications with market potential: increasing the temporal and spatial resolution of UEDs, and increasing the temporal and spatial resolution of DTEMs. Specialized software packages that have been developed by MEBS, Ltd. were used to calculate the electron optical properties of the key pulse compressor components: namely, the magnetic prism, the electron mirror, and the electron lenses. In the final step, these results were folded

  18. High-speed pulse techniques

    CERN Document Server

    Coekin, J A


    High-Speed Pulse Techniques covers the many aspects of technique in digital electronics and encompass some of the more fundamental factors that apply to all digital systems. The book describes the nature of pulse signals and their deliberate or inadvertent processing in networks, transmission lines and transformers, and then examines the characteristics and transient performance of semiconductor devices and integrated circuits. Some of the problems associated with the assembly of these into viable systems operating at ultra high speed are also looked at. The book examines the transients and w

  19. Neuromuscular disruption with ultrashort electrical pulses (United States)

    Pakhomov, Andrei; Kolb, Juergen F.; Joshi, Ravindra P.; Schoenbach, Karl H.; Dayton, Thomas; Comeaux, James; Ashmore, John; Beason, Charles


    Experimental studies on single cells have shown that application of pulsed voltages, with submicrosecond pulse duration and an electric field on the order of 10 kV/cm, causes sudden alterations in the intracellular free calcium concentration, followed by immobilization of the cell. In order to examine electrical stimulation and incapacitation with such ultrashort pulses, experiments on anesthetized rats have been performed. The effect of single, 450 nanosecond monopolar pulses have been compared with that of single pulses with multi-microsecond duration (TASER pulses). Two conditions were explored: 1. the ability to elicit a muscle twitch, and, 2. the ability to suppress voluntary movement by using nanosecond pulses. The second condition is relevant for neuromuscular incapacitation. The preliminary results indicate that for stimulation microsecond pulses are advantageous over nanosecond pulses, whereas for incapacitation, the opposite seems to apply. The stimulation effects seem to scale with electrical charge, whereas the disruption effects don't follow a simple scaling law. The increase in intensity (time of incapacitation) for a given pulse duration, is increasing with electrical energy, but is more efficient for nanosecond than for microsecond pulses. This indicates different cellular mechanisms for incapacitation, most likely subcellular processes, which have been shown to become increasingly important when the pulse duration is shortened into the nanosecond range. If further studies can confirm these initial results, consequences of reduced pulse duration are a reduction in weight and volume of the pulse delivery system, and likely, because of the lower required energy for neuromuscular incapacitation, reduced safety risks.

  20. Control of high power pulse extracted from the maximally compressed pulse in a nonlinear optical fiber

    CERN Document Server

    Yang, Guangye; Jia, Suotang; Mihalache, Dumitru


    We address the possibility to control high power pulses extracted from the maximally compressed pulse in a nonlinear optical fiber by adjusting the initial excitation parameters. The numerical results show that the power, location and splitting order number of the maximally compressed pulse and the transmission features of high power pulses extracted from the maximally compressed pulse can be manipulated through adjusting the modulation amplitude, width, and phase of the initial Gaussian-type perturbation pulse on a continuous wave background.

  1. Pulse Delay and Speed-up of Ultra Fast Pulses in an Absorbing Quantum Well Medium

    DEFF Research Database (Denmark)

    Hansen, Per Lunnemann; Poel, Mike van der; Yvind, Kresten;


    Slow down and speed-up of 180 fs pulses in an absorbing semiconductor beyond the exisitng models is observed. Cascading gainand absorbing sections give us significant temporal pulse shifting at almost constant output pulse energy.......Slow down and speed-up of 180 fs pulses in an absorbing semiconductor beyond the exisitng models is observed. Cascading gainand absorbing sections give us significant temporal pulse shifting at almost constant output pulse energy....

  2. Dynamic Characterization of Fiber Optical Chirped Pulse Amplification for Sub-ps Pulses

    DEFF Research Database (Denmark)

    Cristofori, Valentina; Lali-Dastjerdi, Zohreh; Rishøj, Lars Søgaard


    We investigate experimentally the propagation of sub-picosecond pulses in fiber optical parametric chirped pulse amplifiers, showing a significant broadening of the pulses from 450 fs up to 720 fs due to dispersion and self-phase modulation.......We investigate experimentally the propagation of sub-picosecond pulses in fiber optical parametric chirped pulse amplifiers, showing a significant broadening of the pulses from 450 fs up to 720 fs due to dispersion and self-phase modulation....

  3. 35 Volt, 180 Ampere Pulse Generator with Droop Control for Pulsing Xenon Arcs

    DEFF Research Database (Denmark)

    Hviid, T.; Nielsen, S. O.


    The pulse generator described works as a combined switch and series current regulator and allows the shape of the current pulse to be adjusted at each optical wavelength to produce a flat pulse of monochromatic light.......The pulse generator described works as a combined switch and series current regulator and allows the shape of the current pulse to be adjusted at each optical wavelength to produce a flat pulse of monochromatic light....

  4. Generation of pulsed ion beams by an inductive storage pulsed power generator (United States)

    Katsuki, Sunao; Akiyama, Hidenori; Maeda, Sadao


    A pulsed power generator by an inductive energy storage system is extremely compact and light in comparison with a conventional pulsed power generator, which consists of a Marx bank and a water pulse forming line. A compact and light pulse power generator is applied to the generation of pulsed ion beams. A thin copper fuse is used an an opening switch, which is necessary in the inductive storage pulsed power generator. A magnetically insulated diode is used for the generation of ion beams. The pulsed ion beams are successfully generated by the inductive storage pulsed power generator for the first time.

  5. Cylindrically Polarized Nondiffracting Optical Pulses

    CERN Document Server

    Ornigotti, Marco; Szameit, Alexander


    We extend the concept of radially and azimuthally polarized optical beams to the polychromatic domain by introducing cylindrically polarized nondiffracting optical pulses. In particular, we discuss in detail the case of cylindrically polarized X-waves, both in the paraxial and nonparaxial regime. The explicit expressions for the electric and magnetic fields of cylindrically polarized X-waves is also reported.

  6. Nonparametric estimation of ultrasound pulses

    DEFF Research Database (Denmark)

    Jensen, Jørgen Arendt; Leeman, Sidney


    An algorithm for nonparametric estimation of 1D ultrasound pulses in echo sequences from human tissues is derived. The technique is a variation of the homomorphic filtering technique using the real cepstrum, and the underlying basis of the method is explained. The algorithm exploits a priori...

  7. Wave equations for pulse propagation (United States)

    Shore, B. W.


    Theoretical discussions of the propagation of pulses of laser radiation through atomic or molecular vapor rely on a number of traditional approximations for idealizing the radiation and the molecules, and for quantifying their mutual interaction by various equations of propagation (for the radiation) and excitation (for the molecules). In treating short-pulse phenomena it is essential to consider coherent excitation phenomena of the sort that is manifest in Rabi oscillations of atomic or molecular populations. Such processes are not adequately treated by rate equations for excitation nor by rate equations for radiation. As part of a more comprehensive treatment of the coupled equations that describe propagation of short pulses, this memo presents background discussion of the equations that describe the field. This memo discusses the origin, in Maxwell's equations, of the wave equation used in the description of pulse propagation. It notes the separation into lamellar and solenoidal (or longitudinal and transverse) and positive and negative frequency parts. It mentions the possibility of separating the polarization field into linear and nonlinear parts, in order to define a susceptibility or index of refraction and, from these, a phase and group velocity.

  8. All about Heart Rate (Pulse) (United States)

    ... get a picture of your health. Learn more: Blood Pressure Vs. Heart Rate Target Heart Rate Arrhythmias (abnormal heart rhythms) This ... Healthy 6 What are the Symptoms of High Blood Pressure? 7 All About Heart Rate (Pulse) 8 Warning Signs of a Heart Attack ...

  9. Atomic collisions involving pulsed positrons

    DEFF Research Database (Denmark)

    Merrison, J. P.; Bluhme, H.; Field, D.


    Conventional slow positron beams have been widely and profitably used to study atomic collisions and have been instrumental in understanding the dynamics of ionization. The next generation of positron atomic collision studies are possible with the use of charged particle traps. Not only can large...... of accelerators for producing intense positron pulses will be discussed in the context of atomic physics experiments....

  10. Ptychographic reconstruction of attosecond pulses

    CERN Document Server

    Lucchini, M; Ludwig, A; Gallmann, L; Keller, U; Feurer, T


    We demonstrate a new attosecond pulse reconstruction modality which uses an algorithm that is derived from ptychography. In contrast to other methods, energy and delay sampling are not correlated, and as a result, the number of electron spectra to record is considerably smaller. Together with the robust algorithm, this leads to a more precise and fast convergence of the reconstruction.

  11. CSR Pulsed Switching Power Supplies

    Institute of Scientific and Technical Information of China (English)


    In 2001, CSR power supply system made a great progress. Three prototypes were designed for CSR quadruple and correct magnet. Three different companies provided the three prototypes, but the same circuit-chopper were employed. The simplified diagram is showed in Fig.1. All pulsed switching power supply prototypes were tested successfully before the end of 2001.

  12. Temporal resolution beyond the average pulse duration in shaped noisy-pulse transient absorption spectroscopy. (United States)

    Meyer, Kristina; Müller, Niklas; Liu, Zuoye; Pfeifer, Thomas


    In time-resolved spectroscopy, it is a widespread belief that the temporal resolution is determined by the laser pulse duration. Recently, it was observed and shown that partially coherent laser pulses as they are provided by free-electron-laser (FEL) sources offer an alternative route to reach a temporal resolution below the average pulse duration. Here, we demonstrate the generation of partially coherent light in the laboratory like we observe it at FELs. We present the successful implementation of such statistically fluctuating pulses by using the pulse-shaping technique. These pulses exhibit an average pulse duration about 10 times larger than their bandwidth limit. The shaped pulses are then applied to transient-absorption measurements in the dye IR144. Despite the noisy characteristics of the laser pulses, features in the measured absorption spectra occurring on time scales much faster than the average pulse duration are resolved, thus proving the universality of the described noisy-pulse concept.

  13. Cryosurgery with pulsed electric fields. (United States)

    Daniels, Charlotte S; Rubinsky, Boris


    This study explores the hypothesis that combining the minimally invasive surgical techniques of cryosurgery and pulsed electric fields will eliminate some of the major disadvantages of these techniques while retaining their advantages. Cryosurgery, tissue ablation by freezing, is a well-established minimally invasive surgical technique. One disadvantage of cryosurgery concerns the mechanism of cell death; cells at high subzero temperature on the outer rim of the frozen lesion can survive. Pulsed electric fields (PEF) are another minimally invasive surgical technique in which high strength and very rapid electric pulses are delivered across cells to permeabilize the cell membrane for applications such as gene delivery, electrochemotherapy and irreversible electroporation. The very short time scale of the electric pulses is disadvantageous because it does not facilitate real time control over the procedure. We hypothesize that applying the electric pulses during the cryosurgical procedure in such a way that the electric field vector is parallel to the heat flux vector will have the effect of confining the electric fields to the frozen/cold region of tissue, thereby ablating the cells that survive freezing while facilitating controlled use of the PEF in the cold confined region. A finite element analysis of the electric field and heat conduction equations during simultaneous tissue treatment with cryosurgery and PEF (cryosurgery/PEF) was used to study the effect of tissue freezing on electric fields. The study yielded motivating results. Because of decreased electrical conductivity in the frozen/cooled tissue, it experienced temperature induced magnified electric fields in comparison to PEF delivered to the unfrozen tissue control. This suggests that freezing/cooling confines and magnifies the electric fields to those regions; a targeting capability unattainable in traditional PEF. This analysis shows how temperature induced magnified and focused PEFs could be used to

  14. Cryosurgery with pulsed electric fields.

    Directory of Open Access Journals (Sweden)

    Charlotte S Daniels

    Full Text Available This study explores the hypothesis that combining the minimally invasive surgical techniques of cryosurgery and pulsed electric fields will eliminate some of the major disadvantages of these techniques while retaining their advantages. Cryosurgery, tissue ablation by freezing, is a well-established minimally invasive surgical technique. One disadvantage of cryosurgery concerns the mechanism of cell death; cells at high subzero temperature on the outer rim of the frozen lesion can survive. Pulsed electric fields (PEF are another minimally invasive surgical technique in which high strength and very rapid electric pulses are delivered across cells to permeabilize the cell membrane for applications such as gene delivery, electrochemotherapy and irreversible electroporation. The very short time scale of the electric pulses is disadvantageous because it does not facilitate real time control over the procedure. We hypothesize that applying the electric pulses during the cryosurgical procedure in such a way that the electric field vector is parallel to the heat flux vector will have the effect of confining the electric fields to the frozen/cold region of tissue, thereby ablating the cells that survive freezing while facilitating controlled use of the PEF in the cold confined region. A finite element analysis of the electric field and heat conduction equations during simultaneous tissue treatment with cryosurgery and PEF (cryosurgery/PEF was used to study the effect of tissue freezing on electric fields. The study yielded motivating results. Because of decreased electrical conductivity in the frozen/cooled tissue, it experienced temperature induced magnified electric fields in comparison to PEF delivered to the unfrozen tissue control. This suggests that freezing/cooling confines and magnifies the electric fields to those regions; a targeting capability unattainable in traditional PEF. This analysis shows how temperature induced magnified and focused

  15. Cryosurgery with Pulsed Electric Fields (United States)

    Daniels, Charlotte S.; Rubinsky, Boris


    This study explores the hypothesis that combining the minimally invasive surgical techniques of cryosurgery and pulsed electric fields will eliminate some of the major disadvantages of these techniques while retaining their advantages. Cryosurgery, tissue ablation by freezing, is a well-established minimally invasive surgical technique. One disadvantage of cryosurgery concerns the mechanism of cell death; cells at high subzero temperature on the outer rim of the frozen lesion can survive. Pulsed electric fields (PEF) are another minimally invasive surgical technique in which high strength and very rapid electric pulses are delivered across cells to permeabilize the cell membrane for applications such as gene delivery, electrochemotherapy and irreversible electroporation. The very short time scale of the electric pulses is disadvantageous because it does not facilitate real time control over the procedure. We hypothesize that applying the electric pulses during the cryosurgical procedure in such a way that the electric field vector is parallel to the heat flux vector will have the effect of confining the electric fields to the frozen/cold region of tissue, thereby ablating the cells that survive freezing while facilitating controlled use of the PEF in the cold confined region. A finite element analysis of the electric field and heat conduction equations during simultaneous tissue treatment with cryosurgery and PEF (cryosurgery/PEF) was used to study the effect of tissue freezing on electric fields. The study yielded motivating results. Because of decreased electrical conductivity in the frozen/cooled tissue, it experienced temperature induced magnified electric fields in comparison to PEF delivered to the unfrozen tissue control. This suggests that freezing/cooling confines and magnifies the electric fields to those regions; a targeting capability unattainable in traditional PEF. This analysis shows how temperature induced magnified and focused PEFs could be used to

  16. Wave equations for pulse propagation

    Energy Technology Data Exchange (ETDEWEB)

    Shore, B.W.


    Theoretical discussions of the propagation of pulses of laser radiation through atomic or molecular vapor rely on a number of traditional approximations for idealizing the radiation and the molecules, and for quantifying their mutual interaction by various equations of propagation (for the radiation) and excitation (for the molecules). In treating short-pulse phenomena it is essential to consider coherent excitation phenomena of the sort that is manifest in Rabi oscillations of atomic or molecular populations. Such processes are not adequately treated by rate equations for excitation nor by rate equations for radiation. As part of a more comprehensive treatment of the coupled equations that describe propagation of short pulses, this memo presents background discussion of the equations that describe the field. This memo discusses the origin, in Maxwell's equations, of the wave equation used in the description of pulse propagation. It notes the separation into lamellar and solenoidal (or longitudinal and transverse) and positive and negative frequency parts. It mentions the possibility of separating the polarization field into linear and nonlinear parts, in order to define a susceptibility or index of refraction and, from these, a phase and group velocity. The memo discusses various ways of characterizing the polarization characteristics of plane waves, that is, of parameterizing a transverse unit vector, such as the Jones vector, the Stokes vector, and the Poincare sphere. It discusses the connection between macroscopically defined quantities, such as the intensity or, more generally, the Stokes parameters, and microscopic field amplitudes. The material presented here is a portion of a more extensive treatment of propagation to be presented separately. The equations presented here have been described in various books and articles. They are collected here as a summary and review of theory needed when treating pulse propagation.

  17. Pulse frequency classification based on BP neural network

    Institute of Scientific and Technical Information of China (English)

    WANG Rui; WANG Xu; YANG Dan; FU Rong


    In Traditional Chinese Medicine (TCM), it is an important parameter of the clinic disease diagnosis to analysis the pulse frequency. This article accords to pulse eight major essentials to identify pulse type of the pulse frequency classification based on back-propagation neural networks (BPNN). The pulse frequency classification includes slow pulse, moderate pulse, rapid pulse etc. By feature parameter of the pulse frequency analysis research and establish to identify system of pulse frequency features. The pulse signal from detecting system extracts period, frequency etc feature parameter to compare with standard feature value of pulse type. The result shows that identify-rate attains 92.5% above.

  18. Developing classification indices for Chinese pulse diagnosis

    CERN Document Server

    Shu, Jian-Jun


    Aim: To develop classification criteria for Chinese pulse diagnosis and to objectify the ancient diagnostic technique. Methods: Chinese pulse curves are treated as wave signals. Multidimensional variable analysis is performed to provide the best curve fit between the recorded Chinese pulse waveforms and the collective Gamma density functions. Results: Chinese pulses can be recognized quantitatively by the newly-developed four classification indices, that is, the wave length, the relative phase difference, the rate parameter, and the peak ratio. The new quantitative classification not only reduces the dependency of pulse diagnosis on Chinese physician's experience, but also is able to interpret pathological wrist-pulse waveforms more precisely. Conclusions: Traditionally, Chinese physicians use fingertips to feel the wrist-pulses of patients in order to determine their health conditions. The qualitative theory of the Chinese pulse diagnosis is based on the experience of Chinese physicians for thousands of year...

  19. Dispersion compensation in chirped pulse amplification systems (United States)

    Bayramian, Andrew James; Molander, William A.


    A chirped pulse amplification system includes a laser source providing an input laser pulse along an optical path. The input laser pulse is characterized by a first temporal duration. The system also includes a multi-pass pulse stretcher disposed along the optical path. The multi-pass pulse stretcher includes a first set of mirrors operable to receive input light in a first plane and output light in a second plane parallel to the first plane and a first diffraction grating. The pulse stretcher also includes a second set of mirrors operable to receive light diffracted from the first diffraction grating and a second diffraction grating. The pulse stretcher further includes a reflective element operable to reflect light diffracted from the second diffraction grating. The system further includes an amplifier, a pulse compressor, and a passive dispersion compensator disposed along the optical path.

  20. Linear transformer driver for pulse generation (United States)

    Kim, Alexander A; Mazarakis, Michael G; Sinebryukhov, Vadim A; Volkov, Sergey N; Kondratiev, Sergey S; Alexeenko, Vitaly M; Bayol, Frederic; Demol, Gauthier; Stygar, William A


    A linear transformer driver includes at least one ferrite ring positioned to accept a load. The linear transformer driver also includes a first power delivery module that includes a first charge storage devices and a first switch. The first power delivery module sends a first energy in the form of a first pulse to the load. The linear transformer driver also includes a second power delivery module including a second charge storage device and a second switch. The second power delivery module sends a second energy in the form of a second pulse to the load. The second pulse has a frequency that is approximately three times the frequency of the first pulse. The at least one ferrite ring is positioned to force the first pulse and the second pulse to the load by temporarily isolating the first pulse and the second pulse from an electrical ground.

  1. Exact Solutions to Short Pulse Equation

    Institute of Scientific and Technical Information of China (English)

    FU Zun-Tao; ZHENG Ming-Hua; LIU Shi-Kuo


    In this paper, dependent and independent variable transformations are introduced to solve the short pulse equation. It is shown that different kinds of solutions can be obtained to the short pulse equation.

  2. Digital Communication Using Chaotic Pulse Generators

    CERN Document Server

    Rulkov, N F; Tsimring, L S; Volkovskii, A R; Abarbanel, Henry D I; Larson, L; Yao, K


    Utilization of chaotic signals for covert communications remains a very promising practical application. Multiple studies indicated that the major shortcoming of recently proposed chaos-based communication schemes is their susceptibility to noise and distortions in communication channels. In this talk we discuss a new approach to communication with chaotic signals, which demonstrates good performance in the presence of channel distortions. This communication scheme is based upon chaotic signals in the form of pulse trains where intervals between the pulses are determined by chaotic dynamics of a pulse generator. The pulse train with chaotic interpulse intervals is used as a carrier. Binary information is modulated onto this carrier by the pulse position modulation method, such that each pulse is either left unchanged or delayed by a certain time, depending on whether ``0'' or ``1'' is transmitted. By synchronizing the receiver to the chaotic pulse train we can anticipate the timing of pulses corresponding to ...

  3. Linear transformer driver for pulse generation

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Alexander A; Mazarakis, Michael G; Sinebryukhov, Vadim A; Volkov, Sergey N; Kondratiev, Sergey S; Alexeenko, Vitaly M; Bayol, Frederic; Demol, Gauthier; Stygar, William A


    A linear transformer driver includes at least one ferrite ring positioned to accept a load. The linear transformer driver also includes a first power delivery module that includes a first charge storage devices and a first switch. The first power delivery module sends a first energy in the form of a first pulse to the load. The linear transformer driver also includes a second power delivery module including a second charge storage device and a second switch. The second power delivery module sends a second energy in the form of a second pulse to the load. The second pulse has a frequency that is approximately three times the frequency of the first pulse. The at least one ferrite ring is positioned to force the first pulse and the second pulse to the load by temporarily isolating the first pulse and the second pulse from an electrical ground.

  4. Treatment Pulse Application for Magnetic Stimulation

    Directory of Open Access Journals (Sweden)

    Sun-Seob Choi


    Full Text Available Treatment and diagnosis can be made in difficult areas simply by changing the output pulse form of the magnetic stimulation device. However, there is a limitation in the range of treatments and diagnoses of a conventional sinusoidal stimulation treatment pulse because the intensity, width, and form of the pulse must be changed according to the lesion type. This paper reports a multidischarge method, where the stimulation coils were driven in sequence via multiple switching control. The limitation of the existing simple sinusoidal pulse form could be overcome by changing the intensity, width, and form of the pulse. In this study, a new sequential discharge method was proposed to freely alter the pulse width. The output characteristics of the stimulation treatment pulse were examined according to the trigger signal delay applied to the switch at each stage by applying a range of superposition pulses to the magnetic simulation device, which is widely used in industry and medicine.

  5. Exawatt-Zettawatt Pulse Generation and Applications


    Mourou, G. A.; Fisch, N. J.; Malkin, V. M.; Toroker, Z.; Khazanov, E. A.; Sergeev, A. M.; TAJIMA, T.


    A new amplification method, weaving the three basic compression techniques, Chirped Pulse Amplification (CPA), Optical Parametric Chirped Pulse Amplification (OPCPA) and Plasma Compression by Backward Raman Amplification (BRA) in plasma, is proposed. It is called C3 for Cascaded Conversion Compression. It has the capability to compress with good efficiency kilojoule to megajoule, nanosecond laser pulses into femtosecond pulses, to produce exawatt and beyond peak power. In the future, C3 could...

  6. High Power Picosecond Laser Pulse Recirculation

    Energy Technology Data Exchange (ETDEWEB)

    Shverdin, M Y; Jovanovic, I; Semenov, V A; Betts, S M; Brown, C; Gibson, D J; Shuttlesworth, R M; Hartemann, F V; Siders, C W; Barty, C P


    We demonstrate a nonlinear crystal-based short pulse recirculation cavity for trapping the second harmonic of an incident high power laser pulse. This scheme aims to increase the efficiency and flux of Compton-scattering based light sources. We demonstrate up to 36x average power enhancement of frequency doubled sub-millijoule picosecond pulses, and 17x average power enhancement of 177 mJ, 10 ps, 10 Hz pulses.

  7. High-power picosecond laser pulse recirculation. (United States)

    Shverdin, M Y; Jovanovic, I; Semenov, V A; Betts, S M; Brown, C; Gibson, D J; Shuttlesworth, R M; Hartemann, F V; Siders, C W; Barty, C P J


    We demonstrate a nonlinear crystal-based short pulse recirculation cavity for trapping the second harmonic of an incident high-power laser pulse. This scheme aims to increase the efficiency and flux of Compton-scattering-based light sources. We demonstrate up to 40x average power enhancement of frequency-doubled submillijoule picosecond pulses, and 17x average power enhancement of 177 mJ, 10 ps, 10 Hz pulses.

  8. Nonlinear optics with stationary pulses of light


    Andre, A.; Bajcsy, M.; Zibrov, A. S.; Lukin, M. D.


    We show that the recently demonstrated technique for generating stationary pulses of light [Nature {\\bf 426}, 638 (2003)] can be extended to localize optical pulses in all three spatial dimensions in a resonant atomic medium. This method can be used to dramatically enhance the nonlinear interaction between weak optical pulses. In particular, we show that an efficient Kerr-like interaction between two pulses can be implemented as a sequence of several purely linear optical processes. The resul...

  9. Chirped Pulse Microwave Spectroscopy in Pulsed Uniform Supersonic Flows (United States)

    Abeysekera, Chamara; Oldham, James; Prozument, Kirill; Joalland, Baptiste; Park, Barratt; Field, Robert W.; Sims, Ian; Suits, Arthur; Zack, Lindsay


    We present preliminary results describing the development of a new instrument that combines two powerful techniques: Chirped Pulse-Fourier Transform MicroWave (CP-FTMW) spectroscopy and pulsed uniform supersonic flows. It promises a nearly universal detection method that can deliver quantitative isomer, conformer, and vibrational level specific detection, characterization of unstable reaction products and intermediates and perform unique spectroscopic, kinetics and dynamics measurements. We have constructed a new high-power K_a-band, 26-40 GHz, chirped pulse spectrometer with sub-MHz resolution, analogous to the revolutionary CP-FTMW spectroscopic technique developed in the Pate group at University of Virginia. In order to study smaller molecules, the E-band, 60-90 GHz, CP capability was added to our spectrometer. A novel strategy for generating uniform supersonic flow through a Laval nozzle is introduced. High throughput pulsed piezo-valve is used to produce cold (30 K) uniform flow with large volumes of 150 cm^3 and densities of 1014 molecules/cm3 with modest pumping facilities. The uniform flow conditions for a variety of noble gases extend as far as 20 cm from the Laval nozzle and a single compound turbo-molecular pump maintains the operating pressure. Two competing design considerations are critical to the performance of the system: a low temperature flow is needed to maximize the population difference between rotational levels, and high gas number densities are needed to ensure rapid cooling to achieve the uniform flow conditions. At the same time, collision times shorter than the chirp duration will give inaccurate intensities and reduced signal levels due to collisional dephasing of free induction decay. Details of the instrument and future directions and challenges will be discussed.

  10. Third Harmonic Imaging using a Pulse Inversion

    DEFF Research Database (Denmark)

    Rasmussen, Joachim; Du, Yigang; Jensen, Jørgen Arendt


    The pulse inversion (PI) technique can be utilized to separate and enhance harmonic components of a waveform for tissue harmonic imaging. While most ultrasound systems can perform pulse inversion, only few image the 3rd harmonic component. PI pulse subtraction can isolate and enhance the 3rd...

  11. Pulse crop diseases in the Pacific Northwest (United States)

    The United Nations declared that 2016 is the International Year of Pulses (IYP). This UN declaration of IYP will certainly increase awareness of pulses and likely position pulses as a primary source of protein and other essential nutrients for human diets. The US Pacific Northwest region (Idaho, Or...

  12. Hg-Arc Lamp, Pulse Excitation. (United States)


    References 1. "Pulsed Mercury Capillary Lamps .,"P. Dal Pozzo, R. Polloni, and 0. Svelto , J. Appi. Phys. 6, 342 (1975). * 2. "Pulsed High-Pressure Mercury...Capillary Lamps .. ,P. Dal Pozzo, R. Polloni, * and 0. Svelto , J. Appi. Phys. 6, 381 (1975). 3. "Characteristics of the Radiation Pulses of Very-High

  13. A self-consistent Maltsev pulse model (United States)

    Buneman, O.


    A self-consistent model for an electron pulse propagating through a plasma is presented. In this model, the charge imbalance between plasma ions, plasma electrons and pulse electrons creates the travelling potential well in which the pulse electrons are trapped.

  14. High speed, high current pulsed driver circuit

    Energy Technology Data Exchange (ETDEWEB)

    Carlen, Christopher R.


    Various technologies presented herein relate to driving a LED such that the LED emits short duration pulses of light. This is accomplished by driving the LED with short duration, high amplitude current pulses. When the LED is driven by short duration, high amplitude current pulses, the LED emits light at a greater amplitude compared to when the LED is driven by continuous wave current.

  15. Nonspreading Light Pulses in Photonic Crystals


    Staliunas, K.; Serrat, C.; Herrero, R; Cojocaru, C.; Trull, J.


    We investigate propagation of light pulses in photonic crystals in the vicinity of the zero-diffraction point. We show that Gaussian pulses due to nonzero width of their spectrum spread weakly in space and time during the propagation. We also find the family of nonspreading pulses, propagating invariantly in the vicinity of the zero diffraction point of photonic crystals.

  16. Double pulse Thomson scattering system at RTP

    NARCIS (Netherlands)

    Beurskens, M. N. A.; Barth, C. J.; Chu, C.C.; Donne, A. J. H.; Herranz, J. A.; Cardozo, N. J. L.; van der Meiden, H. J.; Pijper, F.J.


    In this article a double pulse multiposition Thomson scattering diagnostic, under construction at RTP, is discussed. Light from a double pulsed ruby laser (pulse separation: 10-800 mu s, max. 2x12.5 J) is scattered by the free electrons of the tokamak plasma and relayed to a Littrow polychromator fo

  17. <3> OMEGA pulse-forming network

    CERN Multimedia


    Adjustement of the 3 W pulse-forming network of the SPS beam dumping system. When charged at 60 kV, this PFN gives 10 kA, 25 ms current pulses, with oscillations, superimposed on the pulse flat top, of an amplitude of +/- 1 Ka.

  18. Perceptions of European stakeholders of pulse fishing

    NARCIS (Netherlands)

    Kraan, M.L.; Trapman, B.K.; Rasenberg, M.M.M.


    This research project examines the concerns and questions of European stakeholders about pulse fishing, in order to assess to what extent the knowledge agenda on pulse fishing covers these issues. To get a first impression of the concerns about pulse fishing, and to get an idea of the stakeholders t

  19. A Study of New Pulse Auscultation System

    Directory of Open Access Journals (Sweden)

    Ying-Yun Chen


    Full Text Available This study presents a new type of pulse auscultation system, which uses a condenser microphone to measure pulse sound waves on the wrist, captures the microphone signal for filtering, amplifies the useful signal and outputs it to an oscilloscope in analog form for waveform display and storage and delivers it to a computer to perform a Fast Fourier Transform (FFT and convert the pulse sound waveform into a heartbeat frequency. Furthermore, it also uses an audio signal amplifier to deliver the pulse sound by speaker. The study observed the principles of Traditional Chinese Medicine’s pulsing techniques, where pulse signals at places called “cun”, “guan” and “chi” of the left hand were measured during lifting (100 g, searching (125 g and pressing (150 g actions. Because the system collects the vibration sound caused by the pulse, the sensor itself is not affected by the applied pressure, unlike current pulse piezoelectric sensing instruments, therefore, under any kind of pulsing pressure, it displays pulse changes and waveforms with the same accuracy. We provide an acquired pulse and waveform signal suitable for Chinese Medicine practitioners’ objective pulse diagnosis, thus providing a scientific basis for this Traditional Chinese Medicine practice. This study also presents a novel circuit design using an active filtering method. An operational amplifier with its differential features eliminates the interference from external signals, including the instant high-frequency noise. In addition, the system has the advantages of simple circuitry, cheap cost and high precision.

  20. Isolated sub-10 attosecond pulse generation by a 6-fs driving pulse and a 5-fs subharmonic controlling pulse

    Directory of Open Access Journals (Sweden)

    Yunhui Wang


    Full Text Available We theoretically study high-order harmonic generation by quantum path control in a special two-color laser field, which is synthesized by a 6 fs/800 nm fundamental pulse and a weaker 5 fs/1600 nm subharmonic controlling pulse. Single quantum path is selected without optimizing any carrier phase, which not only broadens the harmonic bandwidth to 400 eV, but also enhances the harmonic conversion efficiency in comparison with the short-plus-long scheme, which is based on 5 fs/800 nm driving pulse and 6 fs/1600 nm control pulse. An isolated 8-attosecond pulse is produced with currently available ultrafast laser sources.

  1. Generation of few-cycle terawatt light pulses using optical parametric chirped pulse amplification

    NARCIS (Netherlands)

    Witte, S.; Zinkstok, R.T.; Hogervorst, W.; Eikema, K.S.E.


    We demonstrate the generation of 9.8 +/- 0.3 fs laser pulses with a peak power exceeding one terawatt at 30 Hz repetition rate, using optical parametric chirped pulse amplification. The amplifier is pumped by 140 mJ, 60 ps pulses at 532 nm, and amplifies seed pulses from a Ti: Sapphire oscillator to

  2. A Method for Distinguishing Attosecond Single Pulse from Attosecond Pulse Train

    Institute of Scientific and Technical Information of China (English)

    HUO Yi-Ping; ZENG Zhi-Nan; LI Ru-Xin; XU Zhi-Zhan


    @@ The driving laser field assisted attosecond soft-extreme-ultraviolet (XUV) photo-ionization was used successfully to measure the duration of the attosecond pulse based on the cross-correlation method. However, this method in principle cannot distinguish a single attosecond pulse from the attosecond pulse train. We propose a technique for directly distinguishing attosecond single pulse from attosecond pulse train based on the photo-ionization of atoms by attosecond XUV pulse in the presence of a two-colour strong laser pulse.

  3. CW seeded optical parametric amplifier providing wavelength and pulse duration tunable nearly transform limited pulses. (United States)

    Hädrich, S; Gottschall, T; Rothhardt, J; Limpert, J; Tünnermann, A


    An optical parametric amplifier that delivers nearly transform limited pulses is presented. The center wavelength of these pulses can be tuned between 993 nm and 1070 nm and, at the same time, the pulse duration is varied between 206 fs and 650 fs. At the shortest pulse duration the pulse energy was increased up to 7.2 microJ at 50 kHz repetition rate. Variation of the wavelength is achieved by applying a tunable cw seed while the pulse duration can be varied via altering the pump pulse duration. This scheme offers superior flexibility and scaling possibilities.

  4. Development of high-voltage pulse-slicer unit with variable pulse duration for pulse radiolysis system (United States)

    Upadhyay, J.; Sharma, M. L.; Navathe, C. P.; Toley, M. A.; Shinde, S. J.; Nadkarni, S. A.; Sarkar, S. K.


    A high-voltage pulse-slicer unit with variable pulse duration has been developed and integrated with a 7 MeV linear electron accelerator (LINAC) for pulse radiolysis investigation. The pulse-slicer unit provides switching voltage from 1 kV to 10 kV with rise time better than 5 ns. Two MOSFET based 10 kV switches were configured in differential mode to get variable duration pulses. The high-voltage pulse has been applied to the deflecting plates of the LINAC for slicing of electron beam of 2 μs duration. The duration of the electron beam has been varied from 30 ns to 2 μs with the optimized pulse amplitude of 7 kV to get corresponding radiation doses from 6 Gy to 167 Gy.

  5. Unsplit bipolar pulse forming line (United States)

    Rhodes, Mark A.


    A bipolar pulse forming transmission line module and system for linear induction accelerators having first, second, third, and fourth planar conductors which form a sequentially arranged interleaved stack having opposing first and second ends, with dielectric layers between the conductors. The first and second planar conductors are connected to each other at the first end, and the first and fourth planar conductors are connected to each other at the second end via a shorting plate. The third planar conductor is electrically connectable to a high voltage source, and an internal switch functions to short at the first end a high voltage from the third planar conductor to the fourth planar conductor to produce a bipolar pulse at the acceleration axis with a zero net time integral. Improved access to the switch is enabled by an aperture through the shorting plate and the proximity of the aperture to the switch.

  6. Pulsed Power Driven Fusion Energy

    Energy Technology Data Exchange (ETDEWEB)



    Pulsed power is a robust and inexpensive technology for obtaining high powers. Considerable progress has been made on developing light ion beams as a means of transporting this power to inertial fusion capsules. However, further progress is hampered by the lack of an adequate ion source. Alternatively, z-pinches can efficiently convert pulsed power into thermal radiation, which can be used to drive an inertial fusion capsule. However, a z-pinch driven fusion explosion will destroy a portion of the transmission line that delivers the electrical power to the z-pinch. They investigate several options for providing standoff for z-pinch driven fusion. Recyclable Transmission Lines (RTLs) appear to be the most promising approach.

  7. Acoustic emission linear pulse holography (United States)

    Collins, H.D.; Busse, L.J.; Lemon, D.K.


    This device relates to the concept of and means for performing Acoustic Emission Linear Pulse Holography, which combines the advantages of linear holographic imaging and Acoustic Emission into a single non-destructive inspection system. This unique system produces a chronological, linear holographic image of a flaw by utilizing the acoustic energy emitted during crack growth. The innovation is the concept of utilizing the crack-generated acoustic emission energy to generate a chronological series of images of a growing crack by applying linear, pulse holographic processing to the acoustic emission data. The process is implemented by placing on a structure an array of piezoelectric sensors (typically 16 or 32 of them) near the defect location. A reference sensor is placed between the defect and the array.

  8. Pulsed DEMO design assessment studies

    CERN Document Server

    Todd, T N


    Now that ITER is under construction, interest is increasing in the specification and design of the successor machine, a Demonstration Power Plant (DEMO), which in Europe is coordinated by the EFDA Power Plant Physics and Technology programme. This paper summarises the work carried out for EFDA in 2011-2012 on design issues pertinent to a pulsed version of DEMO, intended to be implemented with little or no extrapolation of technology available today. The work was carried out by the Euratom Fusion Associations CCFE, CEA, CRPP, ENEA and KIT, and in addition to a review of recent relevant literature addressed systems code analyses (pulse length vs. size), erosion of plasma facing components, thermomechanical fatigue in the blanket and first wall, a range of energy storage issues, and fatigue life improvements in Nb3Sn CICC superconductors.

  9. Pulse amplitude modulated chlorophyll fluorometer

    Energy Technology Data Exchange (ETDEWEB)

    Greenbaum, Elias; Wu, Jie


    Chlorophyll fluorometry may be used for detecting toxins in a sample because of changes in micro algae. A portable lab on a chip ("LOAC") based chlorophyll fluorometer may be used for toxin detection and environmental monitoring. In particular, the system may include a microfluidic pulse amplitude modulated ("PAM") chlorophyll fluorometer. The LOAC PAM chlorophyll fluorometer may analyze microalgae and cyanobacteria that grow naturally in source drinking water.

  10. Ultrashort-pulse laser calligraphy

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Weijia; Kazansky, Peter G. [Optoelectronics Research Centre, University of Southampton, SO17 1BJ (United Kingdom); Shimotsuma, Yasuhiko; Sakakura, Masaaki; Miura, Kiyotaka; Hirao, Kazuyuki [Department of Material Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Nishikyo-ku, Kyoto 615-8510 (Japan)


    Control of structural modifications inside silica glass by changing the front tilt of an ultrashort pulse is demonstrated, achieving a calligraphic style of laser writing. The phenomena of anisotropic bubble formation at the boundary of an irradiated region and modification transition from microscopic bubbles formation to self-assembled form birefringence are observed, and the physical mechanisms are discussed. The results provide the comprehensive evidence that the light beam with centrosymmetric intensity distribution can produce noncentrosymmetric material modifications.

  11. Ultrashort-pulse laser calligraphy (United States)

    Yang, Weijia; Kazansky, Peter G.; Shimotsuma, Yasuhiko; Sakakura, Masaaki; Miura, Kiyotaka; Hirao, Kazuyuki


    Control of structural modifications inside silica glass by changing the front tilt of an ultrashort pulse is demonstrated, achieving a calligraphic style of laser writing. The phenomena of anisotropic bubble formation at the boundary of an irradiated region and modification transition from microscopic bubbles formation to self-assembled form birefringence are observed, and the physical mechanisms are discussed. The results provide the comprehensive evidence that the light beam with centrosymmetric intensity distribution can produce noncentrosymmetric material modifications.

  12. a Portable Pulsed Neutron Generator (United States)

    Skoulakis, A.; Androulakis, G. C.; Clark, E. L.; Hassan, S. M.; Lee, P.; Chatzakis, J.; Bakarezos, M.; Dimitriou, V.; Petridis, C.; Papadogiannis, N. A.; Tatarakis, M.


    The design and construction of a pulsed plasma focus device to be used as a portable neutron source for material analysis such as explosive detection using gamma spectroscopy is presented. The device is capable of operating at a repetitive rate of a few Hz. When deuterium gas is used, up to 105 neutrons per shot are expected to be produced with a temporal pulse width of a few tens of nanoseconds. The pulsed operation of the device and its portable size are its main advantage in comparison with the existing continuous neutron sources. Parts of the device include the electrical charging unit, the capacitor bank, the spark switch (spark gap), the trigger unit and the vacuum-fuel chamber / anode-cathode. Numerical simulations are used for the simulation of the electrical characteristics of the device including the scaling of the capacitor bank energies with total current, the pinch current, and the scaling of neutron yields with energies and currents. The MCNPX code is used to simulate the moderation of the produced neutrons in a simplified geometry and subsequently, the interaction of thermal neutrons with a test target and the corresponding prompt γ-ray generation.

  13. Complicated Laser Pulse Generation With Pulse Stacking for D-D ICF

    Institute of Scientific and Technical Information of China (English)

    GAO; Zhi-xing; WANG; Lei-jian; LU; Ze; ZHANG; Hai-feng


    <正>For direct drive fusion, a pre-distorted pulse with the complicated temporal shape is necessary. It is generally accepted that the pulse for shock ignition should begin with a low energy pre-pulse spike (picket) followed by a long (about 10 ns) low intensity foot pulse, which ramps up to an intermediate pedestal (compression pulse) and ends with a short high intensity spike.

  14. Efficient High-Energy Pulse-Train Generation Using a 2 n-Pulse Michelson Interferometer. (United States)

    Siders, C W; Siders, J L; Taylor, A J; Park, S G; Weiner, A M


    We demonstrate a novel, Michelson-based, ultrafast multiplexer with a throughput approaching 100% for a polarization-multiplexed train and 50% for a linearly polarized train, which is compatible with a high-energy pulse train and shaped-pulse generation. The interpulse spacings in the resultant 2(n)-pulse train can be adjusted continuously from multinanoseconds through zero. Using this interferometer, we also demonstrate generation of a 16-pulse train of terahertz pulses.

  15. Method for Generating a Compressed Optical Pulse

    DEFF Research Database (Denmark)


    There is presented a method of for generating a compressed optical pulse (112) comprising emitting from a wavelength tunable microcavity laser system (102), comprising an optical cavity (104) with a mechanically adjustable cavity length (L), a primary optical pulse (111) having a primary temporal...... width (Tl) while adjusting the optical cavity length (L) so that said primary optical pulse comprises temporally separated photons of different wavelengths, and transmitting said pulse through a dispersive medium (114), so as to generate a compressed optical pulse (112) with a secondary temporal width...

  16. Optimal pseudorandom pulse position modulation ladar waveforms. (United States)

    Fluckiger, David U; Boland, Brian F; Marcus, Eran


    An algorithm for generating optimal pseudorandom pulse position modulation (PRPPM) waveforms for ladar ranging is presented. Bistatic ladar systems using Geiger-mode avalanche photodiodes require detection of several pulses in order to generate sufficient target statistics to satisfy some detection decision rule. For targets with large initial range uncertainty, it becomes convenient to transmit a pulse train with large ambiguity range. One solution is to employ a PRPPM waveform. An optimal PRPPM waveform will have minimal sidelobes: equivalent to 1 or 0 counts after the pulse correlation filter (compression). This can be accomplished by generating PRPPM pulse trains with optimal or minimal sidelobe autocorrelation.

  17. Progress in time transfer by laser pulses (United States)

    Li, Xin; Yang, Fu-Min


    Time transfer by laser pulses is based on the propagation of light pulses between satellite and ground clocks or between remote clocks on earth. It will realize the synchronization of these clocks with high accuracy and stability. Several experiments of the time transfer by laser pulses had been successfully carried out in some countries. These experiments validate the feasibility of the synchronization of clocks by laser pulses. The paper describes the results of these experiments. The time comparison by laser pulses between atomic clocks on aircraft and ground ones in the United States, and the LASSO and T2L2 projects in France are introduced in detail.

  18. Ion Acceleration by Short Chirped Laser Pulses

    Directory of Open Access Journals (Sweden)

    Jian-Xing Li


    Full Text Available Direct laser acceleration of ions by short frequency chirped laser pulses is investigated theoretically. We demonstrate that intense beams of ions with a kinetic energy broadening of about 1% can be generated. The chirping of the laser pulse allows the particles to gain kinetic energies of hundreds of MeVs, which is required for hadron cancer therapy, from pulses of energies in the order of 100 J. It is shown that few-cycle chirped pulses can accelerate ions more efficiently than long ones, i.e., higher ion kinetic energies are reached with the same amount of total electromagnetic pulse energy.

  19. Ion Acceleration by Short Chirped Laser Pulses

    CERN Document Server

    Li, Jian-Xing; Keitel, Christoph H; Harman, Zoltán


    Direct laser acceleration of ions by short frequency-chirped laser pulses is investigated theoretically. We demonstrate that intense beams of ions with a kinetic energy broadening of about 1 % can be generated. The chirping of the laser pulse allows the particles to gain kinetic energies of hundreds of MeVs, which is required for hadron cancer therapy, from pulses of energies of the order of 100 J. It is shown that few-cycle chirped pulses can accelerate ions more efficiently than long ones, i.e. higher ion kinetic energies are reached with the same amount of total electromagnetic pulse energy.

  20. Nutritional and health benefits of pulses. (United States)

    Mudryj, Adriana N; Yu, Nancy; Aukema, Harold M


    Pulses (beans, peas, and lentils) have been consumed for at least 10 000 years and are among the most extensively used foods in the world. A wide variety of pulses can be grown globally, making them important both economically as well as nutritionally. Pulses provide protein and fibre, as well as a significant source of vitamins and minerals, such as iron, zinc, folate, and magnesium, and consuming half a cup of beans or peas per day can enhance diet quality by increasing intakes of these nutrients. In addition, the phytochemicals, saponins, and tannins found in pulses possess antioxidant and anti-carcinogenic effects, indicating that pulses may have significant anti-cancer effects. Pulse consumption also improves serum lipid profiles and positively affects several other cardiovascular disease risk factors, such as blood pressure, platelet activity, and inflammation. Pulses are high in fibre and have a low glycemic index, making them particularly beneficial to people with diabetes by assisting in maintaining healthy blood glucose and insulin levels. Emerging research examining the effect of pulse components on HIV and consumption patterns with aging populations indicates that pulses may have further effects on health. In conclusion, including pulses in the diet is a healthy way to meet dietary recommendations and is associated with reduced risk of several chronic diseases. Long-term randomized controlled trials are needed to demonstrate the direct effects of pulses on these diseases.

  1. The Pulse Line Ion Accelerator Concept

    Energy Technology Data Exchange (ETDEWEB)

    Briggs, Richard J.


    The Pulse Line Ion Accelerator concept was motivated by the desire for an inexpensive way to accelerate intense short pulse heavy ion beams to regimes of interest for studies of High Energy Density Physics and Warm Dense Matter. A pulse power driver applied at one end of a helical pulse line creates a traveling wave pulse that accelerates and axially confines the heavy ion beam pulse. Acceleration scenarios with constant parameter helical lines are described which result in output energies of a single stage much larger than the several hundred kilovolt peak voltages on the line, with a goal of 3-5 MeV/meter acceleration gradients. The concept might be described crudely as an ''air core'' induction linac where the PFN is integrated into the beam line so the accelerating voltage pulse can move along with the ions to get voltage multiplication.

  2. Pulse detonation engines and components thereof (United States)

    Tangirala, Venkat Eswarlu (Inventor); Rasheed, Adam (Inventor); Vandervort, Christian Lee (Inventor); Dean, Anthony John (Inventor)


    A pulse detonation engine comprises a primary air inlet; a primary air plenum located in fluid communication with the primary air inlet; a secondary air inlet; a secondary air plenum located in fluid communication with the secondary air inlet, wherein the secondary air plenum is substantially isolated from the primary air plenum; a pulse detonation combustor comprising a pulse detonation chamber, wherein the pulse detonation chamber is located downstream of and in fluid communication with the primary air plenum; a coaxial liner surrounding the pulse detonation combustor defining a cooling plenum, wherein the cooling plenum is in fluid communication with the secondary air plenum; an axial turbine assembly located downstream of and in fluid communication with the pulse detonation combustor and the cooling plenum; and a housing encasing the primary air plenum, the secondary air plenum, the pulse detonation combustor, the coaxial liner, and the axial turbine assembly.

  3. Plasma response to transient high voltage pulses

    Indian Academy of Sciences (India)

    S Kar; S Mukherjee


    This review reports on plasma response to transient high voltage pulses in a low pressure unmagnetized plasma. Mainly, the experiments are reviewed, when a disc electrode (metallic and dielectric) is biased pulsed negative or positive. The main aim is to review the electron loss in plasmas and particle balance during the negative pulse electrode biasing, when the applied pulse width is less than the ion plasma period. Though the applied pulse width is less than the ion plasma period, ion rarefaction waves are excited. The solitary electron holes are reviewed for positive pulsed bias to the electrode. Also the excitation of waves (solitary electron and ion holes) is reviewed for a metallic electrode covered by a dielectric material. The wave excitation during and after the pulse withdrawal, excitation and propagation characteristics of various electrostatic plasma waves are reviewed here.

  4. Phytochemicals for health, the role of pulses. (United States)

    Rochfort, Simone; Panozzo, Joe


    Pulses are the seeds of legumes that are used for human consumption and include peas, beans, lentils, chickpeas, and fava beans. Pulses are an important source of macronutrients, containing almost twice the amount of protein compared to cereal grains. In addition to being a source of macronutrients and minerals, pulses also contain plant secondary metabolites that are increasingly being recognised for their potential benefits for human health. The best-studied legume is the soybean, traditionally regarded as an oilseed crop rather than a pulse. The potential health benefits of soy, particularly with respect to isoflavone content, have been the subject of much research and the focus of several reviews. By comparison, less is known about pulses. This review investigates the health potential of pulses, examining the bioactivity of pulse isoflavones, phytosterols, resistant starch, bioactive carbohydrates, alkaloids and saponins. The evidence for health properties is considered, as is the effect of processing and cooking on these potentially beneficial phytochemicals.

  5. Slow light pulse propagation in dispersive media

    DEFF Research Database (Denmark)

    Nielsen, Torben Roland; Mørk, Jesper; Lavrinenko, Andrei


    -difference-time-domain Maxwell-Bloch simulations and compared to analytic results. For long pulses the group index (transmission) for the combined system is significantly enhanced (reduced) relative to slow light based on purely material or waveguide dispersion. Shorter pulses are strongly distorted and depending on parameters......We present a theoretical and numerical analysis of pulse propagation in a semiconductor photonic crystal waveguide with embedded quantum dots in a regime where the pulse is subjected to both waveguide and material dispersion. The group index and the transmission are investigated by finite...... broadening or break-up of the pulse may be observed. The transition from linear to nonlinear pulse propagation is quantified in terms of the spectral width of the pulse. To cite this article: T.R. Nielsen et al., C. R. Physique 10 (2009). (C) 2009 Academie des sciences. Published by Elsevier Masson SAS. All...

  6. Pulse-Flow Microencapsulation System (United States)

    Morrison, Dennis R.


    The pulse-flow microencapsulation system (PFMS) is an automated system that continuously produces a stream of liquid-filled microcapsules for delivery of therapeutic agents to target tissues. Prior microencapsulation systems have relied on batch processes that involve transfer of batches between different apparatuses for different stages of production followed by sampling for acquisition of quality-control data, including measurements of size. In contrast, the PFMS is a single, microprocessor-controlled system that performs all processing steps, including acquisition of quality-control data. The quality-control data can be used as real-time feedback to ensure the production of large quantities of uniform microcapsules.

  7. High-Precision Pulse Generator (United States)

    Katz, Richard; Kleyner, Igor


    A document discusses a pulse generator with subnanosecond resolution implemented with a low-cost field-programmable gate array (FPGA) at low power levels. The method used exploits the fast carry chains of certain FPGAs. Prototypes have been built and tested in both Actel AX and Xilinx Virtex 4 technologies. In-flight calibration or control can be performed by using a similar and related technique as a time interval measurement circuit by measuring a period of the stable oscillator, as the delays through the fast carry chains will vary as a result of manufacturing variances as well as the result of environmental conditions (voltage, aging, temperature, and radiation).

  8. High-power pulsed lasers

    Energy Technology Data Exchange (ETDEWEB)

    Holzrichter, J.F.


    The ideas that led to the successful construction and operation of large multibeam fusion lasers at the Lawrence Livermore Laboratory are reviewed. These lasers are based on the use of Nd:glass laser materials. However, most of the concepts are applicable to any laser being designed for fusion experimentation. This report is a summary of lectures given by the author at the 20th Scottish University Summer School in Physics, on Laser Plasma Interaction. This report includes basic concepts of the laser plasma system, a discussion of lasers that are useful for short-pulse, high-power operation, laser design constraints, optical diagnostics, and system organization.

  9. FPGA based pulsed NQR spectrometer (United States)

    Hemnani, Preeti; Rajarajan, A. K.; Joshi, Gopal; Motiwala, Paresh D.; Ravindranath, S. V. G.


    An NQR spectrometer for the frequency range of 1 MHz to 5 MHZ has been designed constructed and tested using an FPGA module. Consisting of four modules viz. Transmitter, Probe, Receiver and computer controlled (FPGA & Software) module containing frequency synthesizer, pulse programmer, mixer, detection and display, the instrument is capable of exciting nuclei with a power of 200W and can detect signal of a few microvolts in strength. 14N signal from NaNO2 has been observed with the expected signal strength.

  10. Generation of few-cycle terawatt light pulses using optical parametric chirped pulse amplification. (United States)

    Witte, S; Zinkstok, R; Hogervorst, W; Eikema, K


    We demonstrate the generation of 9.8+/-0.3 fs laser pulses with a peak power exceeding one terawatt at 30 Hz repetition rate, using optical parametric chirped pulse amplification. The amplifier is pumped by 140 mJ, 60 ps pulses at 532 nm, and amplifies seed pulses from a Ti:Sapphire oscillator to 23 mJ/pulse, resulting in 10.5 mJ/pulse after compression while amplified fluorescence is kept below 1%. We employ grating-based stretching and compression in combination with an LCD phase-shaper, allowing compression close to the Fourier limit of 9.3 fs.

  11. Upconversion chirped pulse amplification of ultrashort pulses using a multimode Tm:ZBLAN fiber

    Energy Technology Data Exchange (ETDEWEB)

    Yang, L.M.; Sosnowski, T.; Stock, M.L.; Norris, T.B.; Squier, J.; Mourou, G. [Univ. of Michigan, Ann Arbor, MI (United States). Center for Ultrafast Optical Science; Dennis, M.L.; Duling, I.N. III [Naval Research Lab., Washington, DC (United States)


    Microjoule pulse energies are achieved from a single stage upconversion fiber amplifier for the first time in this demonstration of chirped pulse amplification using a multimode TM:ZBLAN fiber. A Ti:sapphire laser system provides the seed pulse for the upconversion fiber amplifier which produces subpicosecond pulse trains with energies as great as 16 {micro}J at repetition rate of 4.4 kHz. The compressed, pulse peak power is more than 1 MW, and the pulse is characterized both temporally and spatially.

  12. Effects of pulse-to-pulse residual species on discharges in repetitively pulsed discharges through packed bed reactors (United States)

    Kruszelnicki, Juliusz; Engeling, Kenneth W.; Foster, John E.; Kushner, Mark J.


    Atmospheric pressure dielectric barrier discharges (DBDs) sustained in packed bed reactors (PBRs) are being investigated for conversion of toxic and waste gases, and CO2 removal. These discharges are repetitively pulsed having varying flow rates and internal geometries, which results in species from the prior pulse still being in the discharge zone at the time the following discharge pulse occurs. A non-negligible residual plasma density remains, which effectively acts as preionization. This residual charge changes the discharge properties of subsequent pulses, and may impact important PBR properties such as chemical selectivity. Similarly, the residual neutral reactive species produced during earlier pulses will impact the reaction rates on subsequent pulses. We report on results of a computational investigation of a 2D PBR using the plasma hydrodynamics simulator nonPDPSIM. Results will be discussed for air flowing though an array of dielectric rods at atmospheric pressure. The effects of inter-pulse residual species on PBR discharges will be quantified. Means of controlling the presence of residual species in the reactor through gas flow rate, pulse repetition, pulse width and geometry will be described. Comparisons will be made to experiments. Work supported by US DOE Office of Fusion Energy Science and the National Science Foundation.

  13. Magnetization reversal in ultrashort magnetic field pulses

    CERN Document Server

    Bauer, M; Fassbender, J; Hillebrands, B


    We report the switching properties of a thin magnetic film subject to an ultrashort, laterally localized magnetic field pulse, obtained by numerical investigations. The magnetization distribution in the film is calculated on a grid assuming Stoner-like coherent rotation within the grid square size. Perpendicularly and in-plane magnetized films exhibit a magnetization reversal due to a 4 ps magnetic field pulse. Outside the central region the pulse duration is short compared to the precession period. In this area the evolution of the magnetization during the field pulse does not depend strongly on magnetic damping and/or pulse shape. However, the final magnetization distribution is affected by the magnetic damping. Although the pulse duration is short compared to the precession period, the time needed for the relaxation of the magnetization to the equilibrium state is rather large. The influence of the different magnetic anisotropy contributions and the magnetic damping parameter enters into the magnetization ...

  14. Thermoluminescence measurement technique using millisecond temperature pulses. (United States)

    Manfred, Michael E; Gabriel, Nicholas T; Yukihara, Eduardo G; Talghader, Joseph J


    A measurement technique, pulsed thermoluminescence, is described which uses short thermal pulses to excite trapped carriers leading to radiative recombination. The pulses are obtained using microstructures with approximately 500 micros thermal time constants. The technique has many of the advantages of pulsed optically stimulated luminescence without the need for optical sources and filters to isolate the luminescent signal. Charge carrier traps in alpha-Al(2)O(3):C particles on microheaters were filled using 205 nm light. Temperature pulses of 10 and 50 ms were applied to the heaters and compared with a standard thermoluminescence curve taken at a ramp rate of 5 K s(-1). This produced curves of intensity verses temperature similar to standard thermoluminescence except shifted to higher temperatures. The luminescence of single particles was read multiple times with negligible loss of population. The lower limit of the duration of useful pulses appears to be limited by particle size and thermal contact between the particle and heater.

  15. Binary-phase compression of stretched pulses (United States)

    Lozovoy, Vadim V.; Nairat, Muath; Dantus, Marcos


    Pulse stretching and compression are essential for the energy scale-up of ultrafast lasers. Here, we consider a radical approach using spectral binary phases, containing only two values (0 and π) for stretching and compressing laser pulses. We numerically explore different strategies and present results for pulse compression of factors up to a million back to the transform limit and experimentally obtain results for pulse compression of a factor of one hundred, in close agreement with numerical calculations. Imperfections resulting from binary-phase compression are addressed by considering cross-polarized wave generation filtering, and show that this approach leads to compressed pulses with contrast ratios greater than ten orders of magnitude. This new concept of binary-phase stretching and compression, if implemented in a multi-layer optic, could eliminate the need for traditional pulse stretchers and more importantly expensive compressors.

  16. The nonparaxial property of chirped pulsed beam

    Institute of Scientific and Technical Information of China (English)

    Daquan Lu(陆大全); Wei Hu(胡巍); Yizhou Zheng(郑一周); Zhenjun Yang(杨振军)


    The nonparaxial property of the chirped pulsed beam is analyzed both quantitatively and qualitatively.Through the qualitative investigation of the paraxial approximation condition, we show there are chirpinduced changes in the nonparaxial propagation of the chirped pulsed beam. A quantitative nonparaxial correction was developed by use of the perturbational technic and the Fourier transform for a few-cycle chirped pulsed beam with relative small chirp parameter. It was shown that the nonparaxial corrections were enhanced near the leading or trailing edge of pulse depending on weather the chirp parameter is positive or negative. An example for pulsed Gaussian beam driven by a chirped Gaussian pulse is shown in the numerical result to confirm our analysis.

  17. Pulse profile stability of the Crab pulsar

    CERN Document Server

    Jain, Chetana


    We present an X-ray timing analysis of the Crab pulsar, PSR B0531+21, using the archival RXTE data. We have investigated the stability of the Crab pulse profile, in soft (2-20 keV) and hard (30-100 keV) X-ray energies, over the last decade of RXTE operation. The analysis includes measurement of the separation between the two pulse peaks; and intensity and the widths of the two peaks. We did not find any significant time dependency in the pulse shape. The two peaks are stable in phase, intensity and widths, for the last ten years. The first pulse is relatively stronger at soft X-rays. The first pulse peak is narrower than the second peak, in both, soft- and hard X-ray energies. Both the peaks show a slow rise and a steeper fall. The ratio of the pulsed photons in the two peaks is also constant in time.

  18. Ionization of atoms by chirped attosecond pulses

    Institute of Scientific and Technical Information of China (English)

    Tan Fang; Peng Liang-You; Gong Qi-Huang


    We investigate the ionization dynamics of atoms by chirped attosecond pulses using the strong field approximation method. The pulse parameters are carefully chosen in the regime where the strong field approximation method is valid. We analyse the effects of the chirp of attosecond pulses on the energy distributions and the corresponding left-right asymmetry of the ionized electrons. For a single chirped attosecond pulse, the ionized electrons can be redistributed and the left-right asymmetry shows oscillations because of the introduction of the chirp. For time-delayed double attosecond pulses at different intensities with the weaker one chirped, exchanging the order of the two pulses shows a relative shift of the energy spectra, which can be explained by the different effective time delays of different frequency components because of the chirp.

  19. Conditions for effects of radiation pulsing

    CERN Document Server

    Trinkaus, H


    The possibility of pulsing effects on radiation damage is due to differences in the delay times of relevant defect reactions and/or to the non-linear dependence of such reactions on defect production rates. Thus, significant pulsing effects require (1) proper relationships of the internal time scales of defect production and reaction to the time scales of pulsing and (2) sufficiently large pulsing induced fluctuations in relevant microstructural variables. We show that the first condition, which we quantify by a 'relative dynamic bias', is indeed fulfilled in wide ranges of the main irradiation parameters. The second condition, quantified by an 'absolute dynamic bias', is, however, found to restrict the parameter ranges of possible pulsing effects substantially. For planned spallation neutron sources and similar accelerator driven systems facilities we find, for instance, that, in the temperature range of interest, the defect yield of one pulse (controlling the absolute dynamic bias) is much too small to allo...

  20. Chaotic carrier pulse position modulation communication system and method (United States)

    Abarbanel, Henry D. I.; Larson, Lawrence E.; Rulkov, Nikolai F.; Sushchik, Mikhail M.; Tsimring, Lev S.; Volkovskii, Alexander R.


    A chaotic carrier pulse position modulation communication system and method is disclosed. The system includes a transmitter and receiver having matched chaotic pulse regenerators. The chaotic pulse regenerator in the receiver produces a synchronized replica of a chaotic pulse train generated by the regenerator in the transmitter. The pulse train from the transmitter can therefore act as a carrier signal. Data is encoded by the transmitter through selectively altering the interpulse timing between pulses in the chaotic pulse train. The altered pulse train is transmitted as a pulse signal. The receiver can detect whether a particular interpulse interval in the pulse signal has been altered by reference to the synchronized replica it generates, and can therefore detect the data transmitted by the receiver. Preferably, the receiver predicts the earliest moment in time it can expect a next pulse after observation of at least two consecutive pulses. It then decodes the pulse signal beginning at a short time before expected arrival of a pulse.

  1. Near-fault ground motions with prominent acceleration pulses: pulse characteristics and ductility demand

    Institute of Scientific and Technical Information of China (English)

    Mai Tong; Vladimir Rzhevsky; Dai Junwu; George C Lee; Qi Jincheng; Qi Xiaozhai


    Major earthquakes of last 15 years (e.g., Northridge 1994, Kobe 1995 and Chi-Chi 1999) have shown that many near-fault ground motions possess prominent acceleration pulses. Some of the prominent ground acceleration pulses are related to large ground velocity pulses, others are caused by mechanisms that are totally different from those causing the velocity pulses or fling steps. Various efforts to model acceleration pulses have been reported in the literature. In this paper, research results from a recent study of acceleration pulse prominent ground motions and an analysis of structural damage induced by acceleration pulses are summarized. The main results of the study include: (1) temporal characteristics of acceleration pulses; (2) ductility demand spectrum of simple acceleration pulses with respect to equivalent classes of dynamic systems and pulse characteristic parameters; and (3) estimation of fundamental period change under the excitation of strong acceleration pulses. By using the acceleration pulse induced linear acceleration spectrum and the ductility demand spectrum,a simple procedure has been developed to estimate the ductility demand and the fundamental period change of a reinforced concrete (RC) structure under the impact of a strong acceleration pulse.

  2. Pulsed UV and VUV excilamps (United States)

    Tarasenko, Victor F.; Erofeev, Mikhail V.; Kostyrja, Igor D.; Lomaev, Mikhail I.; Rybka, Dmitri V.


    Emission characteristics of a nanosecond discharge in nitrogen, inert gases and its halogenides without preionization of the gap from an auxiliary source have been investigated. A volume discharge, initiated by an avalanche electron beam (VDIAEB) was realized at pressures up to 12 atm. It has been shown that at VDIAEB excitation no less than 90% energy in the 120-850 nm range is emitted by Xe, Kr, Ar dimers. Xenon spectra in the range 120-850 nm and time-amplitude characteristics have been recorded and analyzed for various excitation regimes. In xenon at pressure of 1.2 atm, the energy of spontaneous radiation in the full solid angle was ~ 45 mJ/cm3, and the FWHM of a radiation pulse was ~ 110 ns. The spontaneous radiation power rise in xenon was observed at pressures up to 12 atm. Pulsed power densities of radiation of inert gases halogenides excited by VDIAEB was ~ 4.5 kW/cm2 at efficiency up to 5.5 %.

  3. Calorimeter for pulsed energy sources

    Energy Technology Data Exchange (ETDEWEB)

    Pearce, J.W.; Edmonds, P.H.


    A common problem in plasma physics experiments is the measurement of the energy deposited on a water-cooled plate by a pulsed energy source. Examples of this are neutral-beam-line defining plate and targets and tokamak water-cooled limiters. One method of measuring this energy is to integrate the product of the temperature rise ( and the flow rate (F) of the coolant over the interval between the pulses. The two input parameters and F are derived from a differential thermopile and a turbine flow meter, respectively. A simple digital readout circuit displays the deposited energy in a light-emitting diode display. The circuit uses a commercially available, dual-slope analog-to-digital converter (ADC) in a novel configuration that multiplies and F directly. Calibration of the readout circuit is quick and simple, and short-term accuracies of 5% are easily obtained. Over longer periods the accuracy becomes degraded, primarily by thermal drifts in the thermopile amplifier and in the thermopile connections and the wiring. This offset must be compensated for by a simple adjustment before each experimental run. This readout circuit has been used successfully on the Impurity Study Experiment (ISX-B) neutral beam lines and is most convenient for deposited energy measurements in applications in which computerized data acquisition is not available.

  4. Interferência da coloração de esmaltes de unha e do tempo na oximetria de pulso em voluntários sadios Interference of nail polish colors and time on pulse oximetry in healthy volunteers

    Directory of Open Access Journals (Sweden)

    Mara Harumi Miyake


    Full Text Available INTRODUÇÃO: A oximetria de pulso é um método não invasivo de mensuração da saturação periférica da oxiemoglobina (SpO2. É freqüentemente utilizado em unidades de emergência, de terapia intensiva e em centro cirúrgico. A leitura da oximetria de pulso tem acurácia limitada na presença de metaemoglobina, carboxiemoglobina, anemia, vasoconstrição periférica, esmalte de unha, luz fluorescente e movimentação. OBJETIVO: Avaliar a interferência da coloração de esmalte de unha e do tempo sobre a SpO2 em indivíduos sadios. MÉTODO: Participaram do estudo 61 voluntárias sadias, com idades entre 18 e 32 anos. Foi avaliada SpO2 nas seguintes colorações de esmaltes: base (dedo mínimo, rosa claro (dedo anular, rosa claro com cintilante (dedo médio e vermelha (polegar. O indicador não recebeu esmalte. Foi analisado o tempo para cada coloração de esmalte, a cada minuto até completar cinco minutos. RESULTADOS: Quando comparadas as medidas da SpO2 com o controle, as colorações base (p = 0,56, rosa claro (p = 0,56 e rosa claro com cintilante (p = 0,37 não apresentaram diferença estatisticamente significante. A SpO2 apresentou variação significante na cor vermelha (p BACKGROUND: Pulse oximetry is a noninvasive method to measure the saturation of peripheral oxyhaemoglobin (SpO2. It's usually used in emergency, intensive care and operating room units. Pulse oximeter readings have limited accuracy in the presence of methemoglobin, carboxyhemoglobin, anaemia, peripheral vasoconstriction, nail polish, fluorescent light, and motion. OBJECTIVES: To evaluate the interferences of the color of nail polishes and time on SpO2 in healthy individuals. METHODS: Sixty-one healthy female volunteers, ages ranging from 18 to 32 years. The nail polish colors used to evaluate SpO2 were: base coat on the little finger, light pink on the ring finger, sparkling light pink on the medium finger and red on the thumb. The index finger was used as control

  5. Pulse compression by use of deformable mirrors. (United States)

    Zeek, E; Maginnis, K; Backus, S; Russek, U; Murnane, M; Mourou, G; Kapteyn, H; Vdovin, G


    An electrostatically deformable, gold-coated, silicon nitride membrane mirror was used as a phase modulator to compress pulses from 92 to 15 fs. Both an iterative genetic algorithm and single-step dispersion compensation based on frequency-resolved optical gating calibration of the mirror were used to compress pulses to within 10% of the transform limit. Frequency-resolved optical gating was used to characterize the pulses and to test the range of the deformable-mirror-based compressor.

  6. New pulse modulator with low switching frequency

    Directory of Open Access Journals (Sweden)

    Golub V. S.


    Full Text Available The author presents an integrating pulse modulator (analog signal converter with the pulse frequency and duration modulation similar to sigma-delta modulation (with low switching frequency, without quantization. The modulator is characterized by the absence of the quantization noise inherent in sigma-delta modulator, and a low switching frequency, unlike the pulse-frequency modulator. The modulator is recommended, in particular, to convert signals at the input of the class D power amplifier.


    Energy Technology Data Exchange (ETDEWEB)

    Robert States


    Non steady impingement heat transfer is measured. Impingement heating consumes 130 T-BTU/Yr in paper drying, but is only 25% thermally efficient. Pulse impingement is experimentally shown to enhance heat transfer by 2.8, and may deliver thermal efficiencies near 85%. Experimental results uncovered heat transfer deviations from steady theory and from previous investigators, indicating the need for further study and a better theoretical framework. The pulse burner is described, and its roll in pulse impingement is analyzed.

  8. One laser pulse generates two photoacoustic signals


    Gao, Fei; Feng, Xiaohua; Bai, Linyi; Zhang, Ruochong; Liu, Siyu; Ding, Ran; Kishor, Rahul; Zhao, Yanli; Zheng, Yuanjin


    Photoacoustic sensing and imaging techniques have been studied widely to explore optical absorption contrast based on nanosecond laser illumination. In this paper, we report a long laser pulse induced dual photoacoustic (LDPA) nonlinear effect, which originates from unsatisfied stress and thermal confinements. Being different from conventional short laser pulse illumination, the proposed method utilizes a long square-profile laser pulse to induce dual photoacoustic signals. Without satisfying...

  9. Subthreshold pair production in short laser pulses


    Nousch, T.; Seipt, D.; Kampfer, B.; Titov, A. I.


    The $e^+e^-$ pair production by a probe photon traversing a linearly polarized laser pulse is treated as generalized nonlinear Breit-Wheeler process. For short laser pulses with very few oscillations of the electromagnetic field we find below the perturbative weak-field threshold $\\sqrt{s} = 2m$ a similar enhancement of the pair production rate as for circular polarization. The strong subthreshold enhancement is traced back to the finite bandwidth of the laser pulse. A folding model is develo...

  10. Picosecond Pulse Laser Microstructuring of silicon

    Institute of Scientific and Technical Information of China (English)

    赵明; 尹钢; 朱京涛; 赵利


    We report the experimental results of picosecond pulse laser microstructuring (pulse duration 35ps, wavelength 1.06μm, repetition rate 10Hz) of silicon using the direct focusing technique. Arrays of sharp conical spikes located below the initial surface have been formed by cumulative picosecond pulsed laser irradiation of silicon in SF6. Irradiation of silicon surface in air, N2, or vacuum creates ripple-like patterns, but does not create the sharp conical spikes.

  11. Multiple-beam pulse shaping and preamplification

    Energy Technology Data Exchange (ETDEWEB)

    Wilcox, R.B.; VanWonterghem, B.W.; Burkhart, S.C.; Davin, J.M.


    Glass fusion laser systems typically use a master oscillator-power amplifier (MOPA) architecture, where control of the optical pulse temporal and spatial parameters is accomplished mainly in the master oscillator and low power optics. The pulses from this low power ``front end`` are amplified in the power amplifier, which modifies the pulse shape temporally and spatially. Nonlinear frequency conversion crystals following the amplifier further change the pulse before it reaches the target. To effectively control the optical pulse on target for different types of experiments, and compensate for nonlinearity in the preceding optics, the front end system must be versatile enough to easily control many pulse parameters over a large range. The front end pulse generation system described in this article represents a new approach to this problem. The proposed National Ignition Facility (NIF) has 192 beamlines, each of which requires an input pulse of up to 12 Joules in around 4 ns equivalent square pulse length. Considerations of laser architecture for supplying each of these beamlines from a central oscillator system were crucial in the design of the front end. Previous lasers have used bulk optics to split a single oscillator signal and report beams to multiple amplifier chains. A key idea in the current design is to replace bulk optic transport with fibers, eliminating large opto-mechanical subsystems. Another important concept is convenient pulse forming using low voltage integrated optic modulators. The integrated optic and fiber optic concepts resulted in the current pulse generation designs for NEF. An important advantage is that each of the beamlines can have an independently controlled temporal pulse shape, which provides for precise balance of instantaneous power on target.

  12. Investigation of pulsed voltage limiters characteristics

    Directory of Open Access Journals (Sweden)

    Karimov A. V.


    Full Text Available A new method for measuring the voltage limit is offered. It has been designed to measure high-power pulsed current of voltage limiters. The error of this method is half as much as the error of the known method of direct measurement. The investigation of dependence of power capability of single-crystal and double-crystal voltage limiters and of the pulsed operation time on pulse duration.

  13. Pulsed Single Frequency MOPA Laser Project (United States)

    National Aeronautics and Space Administration — Latest advances in semiconductor optoelectronics makes it possible to develop compact light weight robust sources of coherent optical pulses, demanded for numerous...

  14. Ultrashort Laser Pulses in Biology and Medicine

    CERN Document Server

    Braun, Markus; Zinth, Wolfgang


    Sources of ultrashort laser pulses are nowadays commercially available and have entered many areas of research and development. This book gives an overview of biological and medical applications of these laser pulses. The briefness of these laser pulses permits the tracing of the fastest processes in photo-active bio-systems, which is one focus of the book. The other focus is applications that rely on the high peak intensity of ultrashort laser pulses. Examples covered span non-linear imaging techniques, optical tomography, and laser surgery.

  15. Directed cell movement in pulsed electric fields. (United States)

    Franke, K; Gruler, H


    Human granulocytes exposed to pulsed electric guiding fields were investigated. The trajectories were determined from digitized pictures (phase contrast). The basic results are: (i) No directed response was induced by pulsed electric guiding fields having a zero averaged field. (ii) A directed response was induced by pulsed electric guiding fields having a non-zero averaged field. (iii) The directed response was enhanced for pulse sequences having a repetition time of 8 s. (iv) The lag-time between signal recognition and cellular response was 8-10 s. The results are discussed in the framework of a self-ignition model.

  16. Subthreshold pair production in short laser pulses

    CERN Document Server

    Nousch, T; Kampfer, B; Titov, A I


    The $e^+e^-$ pair production by a probe photon traversing a linearly polarized laser pulse is treated as generalized nonlinear Breit-Wheeler process. For short laser pulses with very few oscillations of the electromagnetic field we find below the perturbative weak-field threshold $\\sqrt{s} = 2m$ a similar enhancement of the pair production rate as for circular polarization. The strong subthreshold enhancement is traced back to the finite bandwidth of the laser pulse. A folding model is developed which accounts for the interplay of the frequency spectrum and the intensity distribution in the course of the pulse.

  17. Pulse front control with adaptive optics (United States)

    Sun, B.; Salter, P. S.; Booth, M. J.


    The focusing of ultrashort laser pulses is extremely important for processes including microscopy, laser fabrication and fundamental science. Adaptive optic elements, such as liquid crystal spatial light modulators or membrane deformable mirrors, are routinely used for the correction of aberrations in these systems, leading to improved resolution and efficiency. Here, we demonstrate that adaptive elements used with ultrashort pulses should not be considered simply in terms of wavefront modification, but that changes to the incident pulse front can also occur. We experimentally show how adaptive elements may be used to engineer pulse fronts with spatial resolution.

  18. MEDEA II two-pulse generator development (United States)

    Bieniosek, F. M.; Honig, J.; Theby, E. A.


    This article discusses improvements in the efficiency, output power, and operational flexibility of MEDEA II, a double-pulse electron beam accelerator at McDonnell Douglas Research Laboratories. A modified charging circuit, based on the triple-resonance pulse transformer concept, was implemented on both of MEDEA II's two stages. The output switches were modified to increase maximum output voltages, and a new, second output switch with asymmetric breakdown characteristics was developed. To avoid degradation of the second-pulse output waveform at the diode, a keep-alive circuit was installed. The effects of diode closure on double-pulse operation are also discussed.

  19. Light Pulses to Photomultipliers from Extended Scintillators

    CERN Document Server

    Boemi, D; CERN. Geneva; Costa, S; Insolia, A; Panebianco, S; Potenza, R; Randazzo, N; Reito, S; Romanski, J; Russo, G V; Tuvé, C


    Light pulses received by photomultipliers coupled to scintillators are investigated in the cases of long scintillator slats or rods as well as large disc-shaped ones and compared with pulses from point-like scintillators. Results of experimental tests for the disc-shaped configuration performed with the single photon counting technique are presented and compared with numerical calculations. The calculations were done describing light pulse shape by means of a quite new general analytical method based on virtual light paths and images from geometrical optics. The associated electric pulses from the photomultipliers are then discussed and their dependence from source-photocathode distance are put in light.

  20. A Pulsed Spectrometer Designed for Feedback NQR (United States)

    Schiano, J. L.; Ginsberg, M. D.


    A pulsed NQR spectrometer specifically designed to facilitate real-time tuning of pulse sequence parameters is described. A modular approach based on the interconnection of several rack-mounted blocks provides easy access to all spectrometer signals and simplifies the task of modifying the spectrometer design. We also present experimental data that demonstrates the ability of the spectrometer to increase the signal to noise ratio of NQR measurements by automatically adjusting the pulse width in the strong off-resonant comb pulse sequence.

  1. Group velocity and pulse lengthening of mismatched laser pulses in plasma channels

    Energy Technology Data Exchange (ETDEWEB)

    Schroeder, Carl; Benedetti, Carlo; Esarey, Eric; van Tilborg, Jeroen; Leemans, Wim


    Analytic solutions are presented to the non-paraxial wave equation describing an ultra-short, low-power, laser pulse propagating in aplasma channel. Expressions for the laser pulse centroid motion and laser group velocity are derived, valid for matched and mismatchedpropagation in a parabolic plasma channel, as well as in vacuum, for an arbitrary Laguerre-Gaussian laser mode. The group velocity of amismatched laser pulse, for which the laser spot size is strongly oscillating, is found to be independent of propagation distance andsignificantly less than that of a matched pulse. Laser pulse lengthening of a mismatched pulse owing to laser mode slippage isexamined and found to dominate over that due to dispersive pulse spreading for sufficiently long pulses. Analytic results are shown tobe in excellent agreement with numerical solutions of the full Maxwell equations coupled to the plasma response. Implications for plasmachannel diagnostics are discussed.

  2. Generation of laser pulse trains for tests of multi-pulse laser wakefield acceleration (United States)

    Shalloo, R. J.; Corner, L.; Arran, C.; Cowley, J.; Cheung, G.; Thornton, C.; Walczak, R.; Hooker, S. M.


    In multi-pulse laser wakefield acceleration (MP-LWFA) a plasma wave is driven by a train of low-energy laser pulses separated by the plasma period, an approach which offers a route to driving plasma accelerators with high efficiency and at high pulse repetition rates using emerging technologies such as fibre and thin-disk lasers. Whilst these laser technologies are in development, proof-of-principle tests of MP-LWFA require a pulse train to be generated from a single, high-energy ultrafast pulse. Here we demonstrate the generation of trains of up to 7 pulses with pulse separations in the range 150-170 fs from single 40 fs pulses produced by a Ti:sapphire laser.

  3. A Mutual Pulse Injection-Seeding Scheme for Optical Short Pulse Generation

    Institute of Scientific and Technical Information of China (English)

    D.; N.; Wang


    A mutual pulse injection-seeding scheme is developed to produce wavelength tunable optical short pulse generation. The sidemode suppression ratio obtained is more than 31 dB over the wavelength-tuning rang of 18 nm.

  4. Generation of laser pulse trains for tests of multi-pulse laser wakefield acceleration

    Energy Technology Data Exchange (ETDEWEB)

    Shalloo, R.J., E-mail:; Corner, L.; Arran, C.; Cowley, J.; Cheung, G.; Thornton, C.; Walczak, R.; Hooker, S.M.


    In multi-pulse laser wakefield acceleration (MP-LWFA) a plasma wave is driven by a train of low-energy laser pulses separated by the plasma period, an approach which offers a route to driving plasma accelerators with high efficiency and at high pulse repetition rates using emerging technologies such as fibre and thin-disk lasers. Whilst these laser technologies are in development, proof-of-principle tests of MP-LWFA require a pulse train to be generated from a single, high-energy ultrafast pulse. Here we demonstrate the generation of trains of up to 7 pulses with pulse separations in the range 150–170 fs from single 40 fs pulses produced by a Ti:sapphire laser.

  5. Generalized Short Pulse Equation for Propagation of Few-Cycle Pulses in Metamaterials

    CERN Document Server

    Pietrzyk, Monika E


    We show that propagation of ultrashort (few-cycle) pulses in nonlinear Drude metamaterials with both electric and magnetic Kerr nonlinearities is described by coupled generalized Short Pulse Equations. The resulting system of equations generalizes to the case of metamaterials both the Short Pulse Equation and its vector generalizations which describe the few-cycle pulses in dielectric optical fibers beyond the slowly varying envelope approximation leading to the nonlinear Schroedinger equation.

  6. Efficient chirped-pulse amplification of sub-20 fs laser pulses

    Energy Technology Data Exchange (ETDEWEB)

    Matsuoka, Shinichi; Yamakawa, Koichi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment


    We have developed a model for ultrabroadband and ultrashort pulse amplification including the effects of a pulse shaper for regenerative pulse shaping, gain narrowing and gain saturation in the amplifiers. Thin solid etalons are used to control both gain narrowing and gain saturation during amplification. This model has been used to design an optimized Ti:sapphire amplifier system for producing efficiently pulses of < 20-fs duration with approaching peak and average powers of 100 TW and 20 W. (author)

  7. Fiber Optical Parametric Chirped Pulse Amplification of Sub-Picosecond Pulses

    DEFF Research Database (Denmark)

    Cristofori, Valentina; Lali-Dastjerdi, Zohreh; Da Ros, Francesco


    We demonstrate experimentally, for the first time to our knowledge, fiber optical parametric chirped pulse amplification of 400-fs pulses. The 400-fs signal is stretched, amplified by 26 dB and compressed back to 500 fs.......We demonstrate experimentally, for the first time to our knowledge, fiber optical parametric chirped pulse amplification of 400-fs pulses. The 400-fs signal is stretched, amplified by 26 dB and compressed back to 500 fs....

  8. Pulse Consumption, Satiety, and Weight Management1 (United States)

    McCrory, Megan A.; Hamaker, Bruce R.; Lovejoy, Jennifer C.; Eichelsdoerfer, Petra E.


    The prevalence of obesity has reached epidemic proportions, making finding effective solutions to reduce obesity a public health priority. One part of the solution could be for individuals to increase consumption of nonoilseed pulses (dry beans, peas, chickpeas, and lentils), because they have nutritional attributes thought to benefit weight control, including slowly digestible carbohydrates, high fiber and protein contents, and moderate energy density. Observational studies consistently show an inverse relationship between pulse consumption and BMI or risk for obesity, but many do not control for potentially confounding dietary and other lifestyle factors. Short-term (≤1 d) experimental studies using meals controlled for energy, but not those controlled for available carbohydrate, show that pulse consumption increases satiety over 2–4 h, suggesting that at least part of the effect of pulses on satiety is mediated by available carbohydrate amount or composition. Randomized controlled trials generally support a beneficial effect of pulses on weight loss when pulse consumption is coupled with energy restriction, but not without energy restriction. However, few randomized trials have been conducted and most were short term (3–8 wk for whole pulses and 4–12 wk for pulse extracts). Overall, there is some indication of a beneficial effect of pulses on short-term satiety and weight loss during intentional energy restriction, but more studies are needed in this area, particularly those that are longer term (≥1 y), investigate the optimal amount of pulses to consume for weight control, and include behavioral elements to help overcome barriers to pulse consumption. PMID:22043448

  9. Standardization of Rocket Engine Pulse Time Parameters (United States)

    Larin, Max E.; Lumpkin, Forrest E.; Rauer, Scott J.


    Plumes of bipropellant thrusters are a source of contamination. Small bipropellant thrusters are often used for spacecraft attitude control and orbit correction. Such thrusters typically operate in a pulse mode, at various pulse lengths. Quantifying their contamination effects onto spacecraft external surfaces is especially important for long-term complex-geometry vehicles, e.g. International Space Station. Plume contamination tests indicated the presence of liquid phase contaminant in the form of droplets. Their origin is attributed to incomplete combustion. Most of liquid-phase contaminant is generated during the startup and shutdown (unsteady) periods of thruster pulse. These periods are relatively short (typically 10-50 ms), and the amount of contaminant is determined by the thruster design (propellant valve response, combustion chamber size, thruster mass flow rate, film cooling percentage, dribble volume, etc.) and combustion process organization. Steady-state period of pulse is characterized by much lower contamination rates, but may be lengthy enough to significantly conh'ibute to the overall contamination effect. Because there was no standard methodology for thruster pulse time division, plume contamination tests were conducted at various pulse durations, and their results do not allow quantifying contaminant amounts from each portion of the pulse. At present, the ISS plume contamination model uses an assumption that all thrusters operate in a pulse mode with the pulse length being 100 ms. This assumption may lead to a large difference between the actual amounts of contaminant produced by the thruster and the model predictions. This paper suggests a way to standardize thruster startup and shutdown period definitions, and shows the usefulness of this approach to better quantify thruster plume contamination. Use of the suggested thruster pulse time-division technique will ensure methodological consistency of future thruster plume contamination test programs

  10. Terahertz pulsed imaging in vivo (United States)

    Pickwell-MacPherson, E.


    Terahertz (1012 Hz) pulsed imaging is a totally non-destructive and non-ionising imaging modality and thus potential applications in medicine are being investigated. In this paper we present results using our hand-held terahertz probe that has been designed for in vivo use. In particular, we use the terahertz probe to perform reflection geometry in vivo measurements of human skin. The hand-held terahertz probe gives more flexibility than a typical flat-bed imaging system, but it also results in noisier data and requires existing processing methods to be improved. We describe the requirements and limitations of system geometry, data acquisition rate, image resolution and penetration depth and explain how various factors are dependent on each other. We show how some of the physical limitations can be overcome using novel data processing methods.

  11. Academic Training - Pulsed SC Magnets

    CERN Multimedia

    Françoise Benz


    2005-2006 ACADEMIC TRAINING PROGRAMME LECTURE SERIES 2, 3, June 29, 30, 31 May, 1, 2 June 11:00-12:00 - Auditorium, bldg 500 Pulsed SC Magnets by M. Wilson Lecture 1. Introduction to Superconducting Materials Type 1,2 and high temperature superconductors; their critical temperature, field & current density. Persistent screening currents and the critical state model. Lecture 2. Magnetization and AC Loss How screening currents cause irreversible magnetization and hysteresis loops. Field errors caused by screening currents. Flux jumping. The general formulation of ac loss in terms of magnetization. AC losses caused by screening currents. Lecture 3. Twisted Wires and Cables Filamentary composite wires and the losses caused by coupling currents between filaments, the need for twisting. Why we need cables and how the coupling currents in cables contribute more ac loss. Field errors caused by coupling currents. Lecture 4. AC Losses in Magnets, Cooling and Measurement Summary of all loss mech...

  12. RANCHERO explosive pulsed power experiments

    CERN Document Server

    Goforth, J H; Armijo, E V; Atchison, W L; Bartos, Yu; Clark, D A; Day, R D; Deninger, W J; Faehl, R J; Fowler, C M; García, F P; García, O F; Herrera, D H; Herrera, T J; Keinigs, R K; King, J C; Lindemuth, I R; López, E; Martínez, E C; Martínez, D; McGuire, J A; Morgan, D; Oona, H; Oro, D M; Parker, J V; Randolph, R B; Reinovsky, R E; Rodríguez, G; Stokes, J L; Sena, F C; Tabaka, L J; Tasker, D G; Taylor, A J; Torres, D T; Anderson, H D; Broste, W B; Johnson, J B; Kirbie, H C


    The authors are developing the RANCHERO high explosive pulsed power (HEPP) system to power cylindrically imploding solid-density liners for hydrodynamics experiments. Their near-term goal is to conduct experiments in the regime pertinent to the Atlas capacitor bank. That is, they will attempt to implode liners of ~50 g mass at velocities approaching 15 km/sec. The basic building block of the HEPP system is a coaxial generator with a 304.8 mm diameter stator, and an initial armature diameter of 152 mm. The armature is expanded by a high explosive (HE) charge detonated simultaneously along its axis. The authors have reported a variety of experiments conducted with generator modules 43 cm long and have presented an initial design for hydrodynamic liner experiments. In this paper, they give a synopsis of their first system test, and a status report on the development of a generator module that is 1.4 m long. (6 refs).

  13. The Body as a Pulse

    Directory of Open Access Journals (Sweden)

    Flavia Liberman


    Full Text Available The body is the focus of many studies and interventions. Some paradigms conceptualize the body only in relation to its motor-sensory characteristics, while others prioritize its psychological dimensions. With the aim of contributing towards formulating other perspectives within this field, some aspects of Stanley Keleman and Regina Favre's conceptualization of the body are presented here. Starting from clinical situations during seminar groups, we can take the body to be a multifaceted multimedia pulse that is continually [de]constructed through encounters. Together with the author's clinical experiences as an occupational therapist and teacher or undergraduates, these conceptualizations serve as a guide to clinical practice that is thought out, constructed and balanced by the body, using body approaches to promote encounters molded by affections and events, in an attempt to create bodies capable of sustaining the lived intensity of experiences, and which enable self-observation, closeness to other people and production of singularities.

  14. Aerospace applications of pulsed plasmas (United States)

    Starikovskiy, Andrey


    The use of a thermal equilibrium plasma for combustion control dates back more than a hundred years to the advent of internal combustion (IC) engines and spark ignition systems. The same principles are still applied today to achieve high efficiency in various applications. Recently, the potential use of nonequilibrium plasma for ignition and combustion control has garnered increasing interest due to the possibility of plasma-assisted approaches for ignition and flame stabilization. During the past decade, significant progress has been made toward understanding the mechanisms of plasma chemistry interactions, energy redistribution and the nonequilibrium initiation of combustion. In addition, a wide variety of fuels have been examined using various types of discharge plasmas. Plasma application has been shown to provide additional combustion control, which is necessary for ultra-lean flames, high-speed flows, cold low-pressure conditions of high-altitude gas turbine engine (GTE) relight, detonation initiation in pulsed detonation engines (PDE) and distributed ignition control in homogeneous charge-compression ignition (HCCI) engines, among others. The present paper describes the current understanding of the nonequilibrium excitation of combustible mixtures by electrical discharges and plasma-assisted ignition and combustion. Nonequilibrium plasma demonstrates an ability to control ultra-lean, ultra-fast, low-temperature flames and appears to be an extremely promising technology for a wide range of applications, including aviation GTEs, piston engines, ramjets, scramjets and detonation initiation for pulsed detonation engines. To use nonequilibrium plasma for ignition and combustion in real energetic systems, one must understand the mechanisms of plasma-assisted ignition and combustion and be able to numerically simulate the discharge and combustion processes under various conditions.

  15. Pulsed Plasma Thruster plume analysis

    Energy Technology Data Exchange (ETDEWEB)

    Parker, K. [Washington Univ., Aerospace and Energetics Research Program, Seattle, WA (United States)


    Micro-Pulsed Plasma Thrusters ({mu}PPTs) are a promising method for precision attitude control for small spacecraft in formation flying. They create an ionized plasma plume, which may interfere with other spacecraft in the formation. To characterize the ions in the plume, a diagnostic has been built that couples a drift tube with an energy analyzer. The drift tube provides time of flight measurements to determine the exhaust velocity, and the energy analyzer discriminates the ion energies. The energy analyzer measures the current on a collector plate downstream of four grids that repel electrons and ions below a specified energy. The first grid lowers the density of the plasma, therefore increasing Debye length. The second and fourth grids have a negative potential applied to them so they repel the electrons, while the third grid's voltage can be varied to repel lower energy ions. The ion energies can be computed by differentiating the data. Combining the information of the ion energies and their velocities identifies the ion masses in the PPT plume. The PPT used for this diagnostic is the micro-PPT developed for the Dawgstar satellite. This PPT uses 5.2 Joules per pulse and has a 2.3 cm{sup 2} propellant area, a 1.3 cm electrode length, and an estimated thrust of 85 {mu}N [C. Rayburn et al., AIAA-2000-3256]. This paper will describe the development and design of the time of flight/gridded energy analyzer diagnostic and present recent experimental results. (Author)

  16. 脉搏血氧仪在经桡动脉入径行经皮冠状动脉介入治疗术后桡动脉压迫止血中的应用%Pulse oximeter in guidance of hemostasis after transradial coronary intervention

    Institute of Scientific and Technical Information of China (English)

    吕学祥; 金志刚; 何望安; 许应杰


    目的 观察经桡动脉入径行经皮冠状动脉介入治疗(percutaneous coronary intervention,PCI)术后患者急性桡动脉闭塞(radial artery occlusion,RAO)的发生率,并探讨脉搏血氧仪监测在桡动脉压迫止血中的作用.方法 选择2013年3月至2014年8月于华润武钢总医院心内科病房经桡动脉入径行PCI的患者502例,将术后常规使用桡动脉压迫器加压止血患者作为常规组(250例),在桡动脉压迫止血同时使用脉搏血氧仪监测血氧饱和度患者作为监测组(252例).所有患者72 h内通过多普勒超声确诊有无RAO.结果 所有患者中经超声检测证实发生急性RAOt4例(2.8%),其中常规组13例(5.2%),监测组1例(0.4%),差异有统计学意义(P<0.01).监测组中2例提前将桡动脉压迫器中气囊减压放气时,穿刺处出血,再次加压后脉搏血氧仪监测显示动脉血氧饱和度低下(<95%),退出监测组,进行直接纱布加压包扎止血,术后经超声检测未发生急性RAO.结论 使用脉搏血氧仪监测下的压迫止血方法能显著降低RAO的发生率.

  17. Evaluation of accuracy of DS-100A probe under Nellcor measurement mode in pulse oximeter%脉搏血氧饱和度仪Nellcor模式DS-100A探头临床应用的准确度评价

    Institute of Scientific and Technical Information of China (English)

    刘晓军; 肖金仿; 侯晓敏; 王海棠; 刘高望; 唐建军


    目的:评价3种国产脉搏血氧饱和度仪Nellcor测量模式探头DS-100A的准确度.方法:当由标准监护仪测得的SpO2分别为100%(T1状态)、92%(T2状态)、85%(T3状态)、78%(T4状态)、70%(B状态)时,记录5个相应状态10例成年健康志愿者分别由Lendeavour 12(结果为L组)、iTM(结果为I组)与PeneView T1(结果为P组)3种患者监护仪DS-1 00A探头监测的SpO2数值,同时监测动脉血氧饱和度值(SaO2),计算SpO2与SaO2的差值,评价3组仪器探头测量SpO2的准确度.结果:当SpO2在70%~100%范围内时,L、I、P组的SpO2准确度均在标准范围内;I组准确度最高,其次为L、P组.对5个状态的3组SpO2值进行两两比较发现,B状态时,P组SpO2值明显高于L组(P<0.05).结论:3种型号脉搏血氧饱和度仪Nellcor模式DS-100A探头所测得的SpO2值都是准确有效的,iTM型号的准确度最高.

  18. Laser system using ultra-short laser pulses (United States)

    Dantus, Marcos; Lozovoy, Vadim V.; Comstock, Matthew


    A laser system using ultrashort laser pulses is provided. In another aspect of the present invention, the system includes a laser, pulse shaper and detection device. A further aspect of the present invention employs a femtosecond laser and binary pulse shaping (BPS). Still another aspect of the present invention uses a laser beam pulse, a pulse shaper and a SHG crystal.

  19. Maximum likelihood estimation of the attenuated ultrasound pulse

    DEFF Research Database (Denmark)

    Rasmussen, Klaus Bolding


    The attenuated ultrasound pulse is divided into two parts: a stationary basic pulse and a nonstationary attenuation pulse. A standard ARMA model is used for the basic pulse, and a nonstandard ARMA model is derived for the attenuation pulse. The maximum likelihood estimator of the attenuated...

  20. Optimization of the LCLS Single Pulse Shutter

    Energy Technology Data Exchange (ETDEWEB)

    Adera, Solomon; /Georgia Tech., Atlanta /SLAC


    A mechanical shutter which operates on demand is used to isolate a single pulse from a 120 Hz X-ray source. This is accomplished with a mechanical shutter which is triggered on demand with frequencies ranging from 0 to 10 Hz. The single pulse shutter is an iron blade that oscillates on a pivot in response to a force generated by a pair of pulsed electromagnets (current driven teeter-totter). To isolate an individual pulse from the X-ray beam, the motion of the mechanical shutter should be synchronized in such a way that it allows a single pulse to pass through the aperture and blocks the other incoming pulses. Two consecutive pulses are only {approx} 8 ms apart and the shutter is required to complete one full cycle such that no two pulses pass through the opening. Also the opening of the shutter blade needs to be at least 4 mm so that a 1 mm diameter rms Gaussian beam can pass through without modulation. However, the 4 mm opening is difficult to obtain due to blade rebound and oscillation of the blade after colliding with the electromagnet. The purpose of this project is to minimize and/or totally eliminate the rebound of the shutter blade in pursuit of maximizing the aperture while keeping the open window interval < {approx}12 ms.

  1. Pulsed electric field inactivation in a microreactor

    NARCIS (Netherlands)

    Fox, M.B.


    Pulsed electric fields (PEF) is a novel, non-thermal pasteurization method which uses short, high electric field pulses to inactivate microorganisms. The advantage of a pasteurization method like PEF compared to regular heat pasteurization is that the taste, flavour, texture and nutritional value ar

  2. Repetitively Pulsed Backward-Wave Oscillator Investigations (United States)


    and the FE phase by applying a’ Y pulsed electric field , Fig. 1. Sawyer-Tower circuit for displaying (4) partial reversal of P. inside the temper- a pulsed electric field to switch the material atures up to the Curie temperature. Tests on into the PE or APE phase. With this combina- a

  3. Fast Heat Pulse Propagation by Turbulence Spreading

    DEFF Research Database (Denmark)

    Naulin, Volker; Juul Rasmussen, Jens; Mantica, Paola


    The propagation of a cold pulse initiated by edge cooling in JET is compared to propagation of the heat wave originating from a modulation of the heating source roughly at mid radius. It is found that the propagation of the cold pulse is by far faster than what could be predicted on the basis of ...

  4. Field mapping of ballistic pressure pulse sources

    Directory of Open Access Journals (Sweden)

    Rad Abtin Jamshidi


    Full Text Available Ballistic pressure pulse sources are used since late 1990s for the extracorporeal treatment of chronic Enthesitis. Newly indications are found in trigger-point-therapy for the treatment of musculoskeletal disorders. In both applications excellent results without relevant side effects were found in clinical trials. The technical principle of pressure pulse source is based on the same techniques used in air guns. A projectile is accelerated by pressurized air and hits the applicator with high kinetic energy. By this a compression wave travels through the material and induces a fast (4..5μs, almost singular pressure pulse of 2..10 MPa, which is followed by an equally short rarefaction phase of about the same amplitude. It is assumed that the pressure pulse accounts for the biomedical effects of the device. The slower inertial motion of the waveguide is damped by elastic stoppers, but still can be measured several micro seconds after the initial pressure pulse. In order to characterize the pressure pulse devices, field mapping is performed on several radial pressure pulse sources using the fiber optic hydrophone and a polyvinylidenfluorid (PVDF piezoelectric hydrophone. It could be shown that the current standard (IEC 61846 is not appropriate for characterization of ballistic pressure pulse sources.

  5. Collaboration among sectors to increase pulse consumption. (United States)

    Curran, Julianne; McLachlan, Milla; Black, Richard; Widders, Irv; Manary, Mark


    The United Nations declaration of 2016 as the International Year of Pulses (IYP) provided an unprecedented opportunity to showcase pulses on the global stage for their contribution to affordable nutrition, health, and sustainability. Despite the IYP's successes in stakeholder engagement, continuing to foster and strengthen partnerships and collaborations is necessary to meet the IYP goals of increased pulse production and consumption for human benefit. Shifting consumer behavior to increase pulse consumption emerged during IYP meetings as a shared priority for all stakeholders. Focusing on this shared priority provides an opportunity to strengthen collaboration among all stakeholder groups for research, education, marketing, and ingredient/food production. Although the IYP officially closed at the end of 2016, the pulse community has an opportunity to continue building successful collaborations. The future research agenda can foster increased pulse production and consumption to address global nutrition, health, and sustainability challenges, provided that it is developed with multisectorial perspectives and cross-disciplinary collaborations. But, most importantly, the research agenda for pulses must be centered more deliberately on the end consumer and how to drive shifts in behavior toward increased pulse consumption, as this is the common shared priority around which all stakeholders can rally.

  6. Generation of Single-Cycle Light Pulses

    Energy Technology Data Exchange (ETDEWEB)

    Stuart, B C; Jovanovic, I; Armstrong, J P; Pyke, B; Crane, J K; Shuttlesworth, R


    Most optical pulses, even at the 10-femtosecond timescale, consist of several oscillations of the electric field. By producing and amplifying an ultra-broadband continuum, single cycle (e 3 fs) or shorter optical pulses may be generated. This requires a very challenging pulse-compression with sub-femtosecond accuracy. Production of these single-cycle pulses will lead to new generations of experiments in the areas of coherent control of chemical excitations and reactions, 0.1-fs high-order harmonic (XUV) generation for probing of materials and fast processes, and selective 3-D micron-scale material removal and modification. We activated the first stage of a planned three-stage optical parametric amplifier (OPA) that would ultimately produce sub-3 fs pulses. Active control with a learning algorithm was implemented to optimize the continuum generated in an argon-filled capillary and to control and optimize the final compressed pulse temporal shape. A collaboration was initiated to coherently control the population of different states upon dissociation of Rb{sub 2}. Except for one final optic, a pulse compressor and diagnostics were constructed to produce and characterize pulses in the 5-fs range from the first OPA stage.

  7. Giant half-cycle attosecond pulses

    CERN Document Server

    Wu, H -C


    Half-cycle picosecond pulses have been produced from thin photo-conductors, when applying an electric field across the surface and switching on conduction by a short laser pulse. Then the transverse current in the wafer plane emits half-cycle pulses in normal direction, and pulses of 500 fs duration and 1e6 V/m peak electric field have been observed. Here we show that single half-cycle pulses of 50 as duration and up to 1e13 V/m can be produced when irradiating a double foil target by intense few-cycle laser pulses. Focused onto an ultra-thin foil, all electrons are blown out, forming a uniform sheet of relativistic electrons. A second layer, placed at some distance behind, reflects the drive beam, but lets electrons pass straight. Under oblique incidence, beam reflection provides the transverse current, which emits intense half-cycle pulses. Such a pulse may completely ionize even heavier atoms. New types of attosecond pump-probe experiments will become possible.

  8. High reliability low jitter pulse generator (United States)

    Savage, Mark E.; Stoltzfus, Brian S.


    A method and concomitant apparatus for generating pulses comprising providing a laser light source, disposing a voltage electrode between ground electrodes, generating laser sparks using the laser light source via laser spark gaps between the voltage electrode and the ground electrodes, and outputting pulses via one or more insulated ground connectors connected to the voltage electrode.

  9. Pulsed laser deposition: metal versus oxide ablation

    NARCIS (Netherlands)

    Doeswijk, L.M.; Rijnders, G.; Blank, D.H.A.


    We present experimental results of pulsed laser interaction with metal (Ni, Fe, Nb) and oxide (TiO2, SrTiO3, BaTiO3) targets. The influence of the laser fluence and the number of laser pulses on the resulting target morphology are discussed. Although different responses for metal and oxide targets t

  10. Design of a Compact Pulsed Power Accelerator

    Institute of Scientific and Technical Information of China (English)


    A 100 kA/60 ns compact pulsed power accelerator was designed to study the influence to the X-pinch by the load. It is composed of a Marx generator, a combined pulse forming (PFL), a gas-filled V/N field distortion switch, a transfer line,

  11. Slow-light pulses in moving media


    Fiurasek, J.; Leonhardt, U.; Parentani, R.


    Slow light in moving media reaches a paradoxical regime when the flow speed of the medium approaches the group velocity of light. Pulses can penetrate a region where a counter-propagating flow exceeds the group velocity. When the counter-flow slows down pulses are reflected.

  12. Fast Heat Pulse Propagation by Turbulence Spreading

    DEFF Research Database (Denmark)

    Naulin, Volker; Juul Rasmussen, Jens; Mantica, Paola


    The propagation of a cold pulse initiated by edge cooling in JET is compared to propagation of the heat wave originating from a modulation of the heating source roughly at mid radius. It is found that the propagation of the cold pulse is by far faster than what could be predicted on the basis of ...

  13. Nasal pulse oximetry overestimates oxygen saturation

    DEFF Research Database (Denmark)

    Rosenberg, J; Pedersen, M H


    Ten surgical patients were monitored with nasal and finger pulse oximetry (Nellcor N-200) for five study periods with alternating mouth and nasal breathing and switching of cables and sensors. Nasal pulse oximetry was found to overestimate arterial oxygen saturation by 4.7 (SD 1.4%) (bias...

  14. Improving Pulsar Timing Precision with Single Pulses

    CERN Document Server

    Kerr, Matthew


    The measurement error of pulse times of arrival (TOAs) in the high S/N limit is dominated by the quasi-random variation of a pulsar's emission profile from rotation to rotation. Like measurement noise, this noise is only reduced as the square root of observing time, posing a major challenge to future pulsar timing campaigns with large aperture telescopes, e.g. the Five-hundred-metre Aperture Spherical Telescope and the Square Kilometre Array. We propose a new method of pulsar timing that attempts to approximate the pulse-to-pulse variability with a small family of 'basis' pulses. If pulsar data are integrated over many rotations, this basis can be used to measure sub-pulse structure. Or, if high-time resolution data are available, the basis can be used to 'tag' single pulses and produce an optimal timing template. With realistic simulations, we show that these applications can dramatically reduce the effect of pulse-to-pulse variability on TOAs. Using high-time resolution data taken from the bright PSR J0835-...

  15. Improving Stability of Pulse Modulator Technology

    Institute of Scientific and Technical Information of China (English)

    ZHANG; Li-feng; ZHU; Zhi-bin; LIU; Bao-jie; YANG; Sheng


    In high voltage pulse modulator,the RD loop and the primary winding of the pulse transformer is parallel,and the negative peak loop and the PFN is parallel.When the modulator is running,the resistor temperature of RD loops and the resistor temperature of reverse peak loop are too high,exceeding 100℃.It can work normally,

  16. Quantum-mechanical analysis of pulse reconstruction for a narrow bandwidth attosecond x-ray pulse

    Institute of Scientific and Technical Information of China (English)

    Ge Yu-Cheng


    The photoelectron energy spectra(PESs)excited by narrow bandwidth attosecond x-ray pulses in the presence of a few-cycle laser are quantum-mechanically calculated.Transfer equations are used to reconstruct the detailed temporal structure of an attosecond x-ray pulse directly from a measured PES.Theoretical analysis shows that the temporal uncertainties of the pulse reconstruction depend on the x-ray bandwidth.The procedure of pulse reconstruction is direct and simple without making any previous pulse assumption,data fitting analysis and time-resolved measurement of PESs.The temporal measurement range is half of a laser optical cycle.

  17. Cavity Optical Pulse Extraction: ultra-short pulse generation as seeded Hawking radiation. (United States)

    Eilenberger, Falk; Kabakova, Irina V; de Sterke, C Martijn; Eggleton, Benjamin J; Pertsch, Thomas


    We show that light trapped in an optical cavity can be extracted from that cavity in an ultrashort burst by means of a trigger pulse. We find a simple analytic description of this process and show that while the extracted pulse inherits its pulse length from that of the trigger pulse, its wavelength can be completely different. Cavity Optical Pulse Extraction is thus well suited for the development of ultrashort laser sources in new wavelength ranges. We discuss similarities between this process and the generation of Hawking radiation at the optical analogue of an event horizon with extremely high Hawking temperature. Our analytic predictions are confirmed by thorough numerical simulations.

  18. Pulse chirp increasing pulse compression followed by positive resonant radiation in fibers

    CERN Document Server

    McLenaghan, Joanna


    Pulse self-compression followed by the generation of resonant radiation is a well known phenomenon in non-linear optics. Resonant radiation is important as it allows for efficient and tunable wavelength conversion. We vary the chirp of the initial pulse and find in simulations and experiments that a small positive chirp enhances the pulse compression and strongly increases the generation of resonant radiation. This result corroborates previously published simulation results indicating an improved degree of pulse compression for a small positive chirp [1]. It also demonstrates how pulse evolution can be studied without cutting back the fiber.

  19. Coherent ultrashort pulse generation from incoherent light by pulse trapping in birefringent fibers. (United States)

    Shiraki, Eiji; Nishizawa, Norihiko


    We investigated the nonlinear fiber phenomena of pulse trapping and amplification between incoherent light and an ultrashort soliton pulse in birefringent fibers both experimentally and numerically. Using the phenomena in a 1.4 km-long low-birefringence fiber, a coherent, nearly transform-limited, sech2-shaped, ultrashort pulse was generated from incoherent light from a super-luminescent diode. The average pulse energy and pulse width were 121 pJ and 640 fs, respectively. The estimated gain of this system was as large as 62 dB.

  20. A Compact Nanosecond-Pulse Shaping System Based on Pulse Stacking in Fibres

    Institute of Scientific and Technical Information of China (English)

    SUI Zhan; LIN Hong-Huan; WANG Jian-Jun; ZHAO Hong-Ming; LI Ming-Zhong; QIAN Lie-Jia; ZHU He-Yuan; FAN Dian-Yuan


    @@ We demonstrate a compact pulse shaping system based on temporal stacking of pulses in fibres, by which synchronized pulses of ultrashort and nanosecond lasers can be obtained. The system may generate shape-controllable pulses with a fast rise time and high-resolution within a time window of ~2.2 ns by adjusting variable optical attenuators in the 32 fibre channels independently. With the help of optical amplifiers, the system delivers mJ-level pulses with a signal-to-noise ratio of~35 dB.