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Sample records for high arterial carbon

  1. Porcine radial artery decellularization by high hydrostatic pressure.

    Science.gov (United States)

    Negishi, Jun; Funamoto, Seiichi; Kimura, Tsuyoshi; Nam, Kwangoo; Higami, Tetsuya; Kishida, Akio

    2015-11-01

    Many types of decellularized tissues have been studied and some have been commercially used in clinics. In this study, small-diameter vascular grafts were made using HHP to decellularize porcine radial arteries. One decellularization method, high hydrostatic pressure (HHP), has been used to prepare the decellularized porcine tissues. Low-temperature treatment was effective in preserving collagen and collagen structures in decellularized porcine carotid arteries. The collagen and elastin structures and mechanical properties of HHP-decellularized radial arteries were similar to those of untreated radial arteries. Xenogeneic transplantation (into rats) was performed using HHP-decellularized radial arteries and an untreated porcine radial artery. Two weeks after transplantation into rat carotid arteries, the HHP-decellularized radial arteries were patent and without thrombosis. In addition, the luminal surface of each decellularized artery was covered by recipient endothelial cells and the arterial medium was fully infiltrated with recipient cells.

  2. Volume-targeted ventilation and arterial carbon dioxide in neonates.

    Science.gov (United States)

    Dawson, Catherine; Davies, Mark William

    2005-01-01

    To review the arterial carbon dioxide tensions (PaCO(2)) in newborn infants ventilated using synchronized intermittent mandatory ventilation (SIMV) in volume guarantee mode (using the Dräger Babylog 8000+) with a unit policy targeting tidal volumes of approximately 4 mL/kg. Data on ventilator settings and arterial PaCO(2) levels were collected on all arterial blood gases (ABG; n = 288) from 50 neonates ( 65 mmHg) were determined. The mean (SD) PaCO(2) during the first 48 h was 46.6 (9.0) mmHg. The mean (SD) PaCO(2) on the first blood gas of those infants commenced on volume guarantee from admission was 45.1 (12.5) mmHg. Severe hypo- or hypercapnoea occurred in 8% of infants at the time of their first blood gas measurement, and in levels at the first blood gas measurement and during the first 48 h of life; and avoid severe hypo- or hypercapnoea over 90% of the time.

  3. Discrepancy between Measured Serum Total Carbon Dioxide Content and Bicarbonate Concentration Calculated from Arterial Blood Gases.

    Science.gov (United States)

    Kim, Youngho; Massie, Larry; Murata, Glen H; Tzamaloukas, Antonios H

    2015-12-07

    Large differences between the concentrations of serum total carbon dioxide (TCO2) and blood gas bicarbonate (HCO3 (-)) were observed in two consecutive simultaneously drawn sets of samples of serum and arterial blood gases in a patient who presented with severe carbon dioxide retention and profound acidemia. These differences could not be explained by the effect of the high partial pressure of carbon dioxide on TCO2, by variations in the dissociation constant of the carbonic acid/bicarbonate system or by faults caused by the algorithms of the blood gas apparatus that calculate HCO3 (-). A recalculation using the Henderson-Hasselbach equation revealed arterial blood gas HCO3 (-) values close to the corresponding serum TCO2 values and clarified the diagnosis of the acid-base disorder, which had been placed in doubt by the large differences between the reported TCO2 and HCO3 (-) values. Human error in the calculation of HCO3 (-) was identified as the source of these differences. Recalculation of blood gas HCO3 (-) should be the first step in identifying the source of large differences between serum TCO2 and blood gas HCO3 (-).

  4. Intra-arterial high signals on arterial spin labeling perfusion images predict the occluded internal carotid artery segment

    Energy Technology Data Exchange (ETDEWEB)

    Sogabe, Shu; Satomi, Junichiro; Tada, Yoshiteru; Kanematsu, Yasuhisa; Kuwayama, Kazuyuki; Yagi, Kenji; Yoshioka, Shotaro; Mizobuchi, Yoshifumi; Mure, Hideo; Yamaguchi, Izumi; Kitazato, Keiko T.; Nagahiro, Shinji [Tokushima University Graduate School, Department of Neurosurgery, Tokushima (Japan); Abe, Takashi; Harada, Masafumi [Tokushima University Graduate School, Department of Radiology, Tokushima (Japan); Yamamoto, Nobuaki; Kaji, Ryuji [Tokushima University Graduate School, Department of Clinical Neurosciences, Institute of Biomedical Biosciences, Tokushima (Japan)

    2017-06-15

    Arterial spin labeling (ASL) involves perfusion imaging using the inverted magnetization of arterial water. If the arterial arrival times are longer than the post-labeling delay, labeled spins are visible on ASL images as bright, high intra-arterial signals (IASs); such signals were found within occluded vessels of patients with acute ischemic stroke. The identification of the occluded segment in the internal carotid artery (ICA) is crucial for endovascular treatment. We tested our hypothesis that high IASs on ASL images can predict the occluded segment. Our study included 13 patients with acute ICA occlusion who had undergone angiographic and ASL studies within 48 h of onset. We retrospectively identified the high IAS on ASL images and angiograms and recorded the occluded segment and the number of high IAS-positive slices on ASL images. The ICA segments were classified as cervical (C1), petrous (C2), cavernous (C3), and supraclinoid (C4). Of seven patients with intracranial ICA occlusion, five demonstrated high IASs at C1-C2, suggesting that high IASs could identify stagnant flow proximal to the occluded segment. Among six patients with extracranial ICA occlusion, five presented with high IASs at C3-C4, suggesting that signals could identify the collateral flow via the ophthalmic artery. None had high IASs at C1-C2. The mean number of high IAS-positive slices was significantly higher in patients with intra- than extracranial ICA occlusion. High IASs on ASL images can identify slow stagnant and collateral flow through the ophthalmic artery in patients with acute ICA occlusion and help to predict the occlusion site. (orig.)

  5. High performance carbon-carbon composites

    Indian Academy of Sciences (India)

    Lalit M Manocha

    2003-02-01

    Carbon-carbon composites rank first among ceramic composite materials with a spectrum of properties and applications in various sectors. These composites are made of fibres in various directions and carbonaceous polymers and hydrocarbons as matrix precursors. Their density and properties depend on the type and volume fraction of reinforcement, matrix precursor used and end heat treatment temperature. Composites made with thermosetting resins as matrix precursors possess low densities (1.55–1.75 g/cm3) and well-distributed microporosity whereas those made with pitch as the matrix precursor, after densification exhibit densities of 1.8–2.0 g/cm3 with some mesopores, and those made by the CVD technique with hydrocarbon gases, possess intermediate densities and matrices with close porosities. The former (resin-based) composites exhibit high flexural strength, low toughness and low thermal conductivity, whereas the latter (pitch- and CVD-based) can be made with very high thermal conductivity (400–700 W/MK) in the fibre direction. Carbon-carbon composites are used in a variety of sectors requiring high mechanical properties at elevated temperatures, good frictional properties for brake pads in high speed vehicles or high thermal conductivity for thermal management applications. However, for extended life applications, these composites need to be protected against oxidation either through matrix modification with Si, Zr, Hf etc. or by multilayer oxidation protection coatings consisting of SiC, silica, zircon etc.

  6. High success rate after arterial renal embolisation

    DEFF Research Database (Denmark)

    Thorlund, Mie Gaedt; Egge Wennevik, Gjertrud; Andersen, Margrethe

    2015-01-01

    INTRODUCTION: The objective of this study was to present patients who underwent either elective or acute renal embolisation in a single centre where embolisation was available at all hours. METHODS: The records of all patients who underwent transcatheter arterial embolisation (TAE) at Odense Univ...

  7. Endotoxemia reduces cerebral perfusion but enhances dynamic cerebrovascular autoregulation at reduced arterial carbon dioxide tension*

    DEFF Research Database (Denmark)

    Brassard, Patrice; Kim, Yu-Sok; van Lieshout, Johannes

    2012-01-01

    OBJECTIVE:: The administration of endotoxin to healthy humans reduces cerebral blood flow but its influence on dynamic cerebral autoregulation remains unknown. We considered that a reduction in arterial carbon dioxide tension would attenuate cerebral perfusion and improve dynamic cerebral......-104] mm Hg; p = .75), but increased cardiac output (8.3 [6.1-9.5] L·min vs. 6.0 [4.5-8.2] L·min; p = .02) through an elevation in heart rate (82 ± 9 beats·min vs. 63 ± 10 beats·min; p arterial carbon dioxide tension (37 ± 5 mm Hg vs. 41 ± 2 mm Hg; p artery mean...... in arterial carbon dioxide tension explains the improved dynamic cerebral autoregulation and the reduced cerebral perfusion encountered in healthy subjects during endotoxemia....

  8. [Digital subtraction angiography with carbon dioxide in severe arterial ischemia and allergy to iodinated compounds].

    Science.gov (United States)

    Calvo Cascallo, J; Mundi Salvadó, N; Cardona Fontanet, M

    1993-01-01

    When in some selected patients, a direct arterial surgery (DAS) procedure or an endoluminal surgery (ES) are required for a chronic arterial ischemia (III or IV degrees), and an arteriography with contrast is absolutely contraindicated (because of severe renal failure without hemodialysis program or a severe congestive heart failure or a hyperthyroidism or a seriously demonstrated hypersensibility against the contrast agents); an angiography by digital subtraction with carbon dioxide (DIVAS-CO2) is indicated. This technique provides good quality images with minimal risks for the patient and an adequate study for ulterior treatment. We report a case of a 67-years-old woman, with diabetes-II, ischemic cardiopathy, arterial hypertension and a demonstrated hypersensibility against the iodide compounds. The patient was admitted because of a chronic ischemia (IV degree) with ischemic ulcerations on some fingers from the left foot. High doses of analgesic drugs were needed. Because the hypersensibility against the iodide compounds, an angiography with CO2 was carried out. The good quality images provided by this technique showed the factibility of a revascularization.

  9. Pulmonary embolism caused by a carbon dioxide blower during off-pump coronary artery bypass grafting.

    Science.gov (United States)

    Hirata, Naoyuki; Kanaya, Noriaki; Yamazaki, Yutaka; Sonoda, Hajime; Namiki, Akiyoshi

    2010-02-01

    We report a rare case of pulmonary embolism (PE) caused by a carbon dioxide (CO2) blower during off-pump coronary artery bypass grafting (OPCAB). When the anastomosis of the right internal thoracic artery to left anterior descending artery was performed, the operator tore the right ventricle outflow track (RVOT) that was adjacent to the left anterior descending artery. Immediately after the anastomosis and repair of the torn RVOT with CO2 blower, the systolic pulmonary artery pressure (PAP) increased from 28 to 64 mmHg, and end-tidal CO2 decreased from 32 to 12 mmHg. Because transesophageal echocardiograph (TEE) showed numerous gas bubbles in the main pulmonary artery, we diagnosed PE caused by invasion of CO2 gas bubbles via the torn RVOT. Although a CO2 blower is useful to enhance visualization of the anastomosis during OPCAB, it should not be used for the venous system because it may cause CO2 embolism.

  10. A comparison of central venous-arterial and mixed venous-arterial carbon dioxide tension gradient in circulatory failure.

    Science.gov (United States)

    Ho, K M; Harding, R; Chamberlain, J

    2007-10-01

    The arterial and mixed venous carbon dioxide tension gradient has been shown to increase when there is a decrease in cardiac output. Monitoring central venous gases is an attractive alternative to monitoring mixed venous gases in circulatory failure because central venous catheterisation is a less invasive procedure than pulmonary artery catheterisation. This study aims to evaluate the agreement between central venous-arterial carbon dioxide (CVA-CO2) and mixed venous-arterial carbon dioxide (SVA-CO2) tension gradients and assess whether CVA-CO2 tension gradient can be used to predict cardiac output in circulatory failure. Samples of arterial, central venous and mixed venous blood were obtained from 16 patients with circulatory failure at different inspired oxygen concentrations and cardiac indexes within 24 hours of study enrolment. CVA-CO2 and SVA-CO2 tension gradient were not interchangeable numerically (bias = 0.14 mmHg, 95% limits of agreement: -3.0 to 3.2 mmHg). CVA-CO2 (Spearman correlation coefficient r = -0.385) and SVA-CO, (r = -0.578) tension gradient were significantly correlated with the cardiac index but the cardiac index only accounted for 21% and 32% of the variability of CVA-CO, and SVA-CO2 tension gradient, respectively. The ability of CVA-CO2 tension gradient (area under the ROC curve = 0.77, 95% confidence interval [CI]: 0.49-0.99; P = 0.08) to predict a low cardiac output state (cardiac index tension gradient appeared to be limited to their negative predictive value to exclude a low cardiac output state when CVA-CO, or SVA-CO, tension gradient was normal (< or =5 mmHg).

  11. High success rate after arterial renal embolisation

    DEFF Research Database (Denmark)

    Thorlund, Mie Gaedt; Wennevik, Gjertrud Egge; Andersen, Margrethe;

    2015-01-01

    INTRODUCTION: The objective of this study was to present patients who underwent either elective or acute renal embolisation in a single centre where embolisation was available at all hours. METHODS: The records of all patients who underwent transcatheter arterial embolisation (TAE) at Odense...... University Hospital from October 2010 to July 2013 were extracted retrospectively and examined to determine the indication for treatment, procedural details and complications. Patients were divided into four groups: renal cancer, trauma, angiomyolipoma (AML) and others. When there was indication...... for embolisation, a renal angiography was performed and followed by embolisation, if possible. The procedure was performed in local analgesia via the common femoral artery and as a super-selective procedure to save as many viable nephrons as possible. The most commonly used embolisation materials were coils...

  12. Estimating Arterial Partial Pressure of Carbon Dioxide in Ventilated Patients: How Valid Are Surrogate Measures?

    Science.gov (United States)

    Nassar, Boulos S; Schmidt, Gregory A

    2017-06-01

    The arterial partial pressure of carbon dioxide (PaCO2) is an important parameter in critically ill, mechanically ventilated patients. To limit invasive procedures or for more continuous monitoring of PaCO2, clinicians often rely on venous blood gases, capnography, or transcutaneous monitoring. Each of these has advantages and limitations. Central venous Pco2 allows accurate estimation of PaCO2, differing from it by an amount described by the Fick principle. As long as cardiac output is relatively normal, central venous Pco2 exceeds the arterial value by approximately 4 mm Hg. In contrast, peripheral venous Pco2 is a poor predictor of PaCO2, and we do not recommend using peripheral venous Pco2 in this manner. Capnography offers measurement of the end-tidal Pco2 (PetCO2), a value that is close to PaCO2 when the lung is healthy. It has the advantage of being noninvasive and continuously available. In mechanically ventilated patients with lung disease, however, PetCO2 often differs from PaCO2, sometimes by a large degree, often seriously underestimating the arterial value. Dependence of PetCO2 on alveolar dead space and ventilator expiratory time limits its value to predict PaCO2. When lung function or ventilator settings change, PetCO2 and PaCO2 can vary in different directions, producing further uncertainty. Transcutaneous Pco2 measurement has become practical and reliable. It is promising for judging steady state values for PaCO2 unless there is overt vasoconstriction of the skin. Moreover, it can be useful in conditions where capnography fails (high-frequency ventilation) or where arterial blood gas analysis is burdensome (clinic or home management of mechanical ventilation).

  13. Disparity between mainstream and sidestream end-tidal carbon dioxide values and arterial carbon dioxide levels.

    Science.gov (United States)

    Pekdemir, Murat; Cinar, Orhan; Yilmaz, Serkan; Yaka, Elif; Yuksel, Melih

    2013-07-01

    Measuring and monitoring end-tidal carbon dioxide (PETCO2) is an important aspect of caring for critically ill patients. The 2 methods used for PETCO2 measurement are the mainstream and sidestream methods. To assess the agreement between PETCO2 measurements performed by mainstream and sidestream methods with the PaCO2 values. This was a prospective observational study. A total of 114 subjects were enrolled in the study. PETCO2 measurements using mainstream and sidestream methods were performed simultaneously with the arterial blood sampling in subjects who were observed in the emergency department and required arterial blood gas analysis. Agreement between the PETCO2 measurements and the PaCO2 values obtained from arterial blood gas analysis were evaluated using the Bland-Altman method. Sixty subjects (52.6%) were female, and the mean age was 60.9 years (95% CI 58.3-63.6). The mean PaCO2 was 35.16 mm Hg (95% CI 33.81-36.51), the mainstream PETCO2 was 22.11 (95% CI 21.05-23.18), and the sidestream PETCO2 was 25.48 (95% CI 24.22-26.75). Bland-Altman analysis showed an average difference between mainstream PETCO2 and PaCO2 values of 13 mm Hg (95% limits of agreement -0.6 to 25.5) and moderate correlation (r = 0.55, P < .001). The average difference between the sidestream PETCO2 and PaCO2 values was 9.7 mm Hg (95% limits of agreement -5.4 to 24.7) and poor correlation (r = 0.41, P < .001). PETCO2 values obtained by mainstream and sidestream methods were found to be significantly lower than the PaCO2 values. There was essentially no agreement between the measurements obtained by 2 different methods and the PaCO2 values.

  14. A CASE REPORT ON HIGH ORIGIN OF RADIAL ARTERY

    Directory of Open Access Journals (Sweden)

    Vaishali Bondage

    2014-09-01

    Full Text Available Background: The use of radial artery (RA as an access to heart and for other procedures and surgeries make it significant. The context and purpose: The RA is a common access port for coronary angiography (CAG, percutaneous coronary intervention (PCI, and coronary artery bypass graft Surgery (CABG, RA cannulation, along with others. Results: In this case report, we want to present a case of unilateral high origin of RA arising as branch of brachial artery in the proximal 1/3rd of arm. Conclusions, brief summary and potential implications: Misdiagnosis, complications during medical procedures and increased possibility of injury are the most common dangers of having a superficial RA.

  15. Sugar-sweetened carbonated beverage consumption and coronary artery calcification in asymptomatic men and women.

    Science.gov (United States)

    Chun, Sohyun; Choi, Yuni; Chang, Yoosoo; Cho, Juhee; Zhang, Yiyi; Rampal, Sanjay; Zhao, Di; Ahn, Jiin; Suh, Byung-Seong; Pastor-Barriuso, Roberto; Lima, Joao A C; Chung, Eun Chul; Shin, Hocheol; Guallar, Eliseo; Ryu, Seungho

    2016-07-01

    Sugar-sweetened carbonated beverage consumption has been linked to obesity, metabolic syndrome, type 2 diabetes, and clinically manifest coronary heart disease, but its association with subclinical coronary heart disease remains unclear. We investigated the relationship between sugar-sweetened carbonated beverage consumption and coronary artery calcium (CAC) in a large study of asymptomatic men and women. This was a cross-sectional study of 22,210 adult men and women who underwent a comprehensive health screening examination between 2011 and 2013 (median age 40 years). Sugar-sweetened carbonated beverage consumption was assessed using a validated food frequency questionnaire, and CAC was measured by cardiac computed tomography. Multivariable-adjusted CAC score ratios and 95% CIs were estimated from robust Tobit regression models for the natural logarithm (CAC score +1). The prevalence of detectable CAC (CAC score >0) was 11.7% (n = 2,604). After adjustment for age; sex; center; year of screening examination; education level; physical activity; smoking; alcohol intake; family history of cardiovascular disease; history of hypertension; history of hypercholesterolemia; and intake of total energy, fruits, vegetables, and red and processed meats, only the highest category of sugar-sweetened carbonated beverage consumption was associated with an increased CAC score compared with the lowest consumption category. The multivariable-adjusted CAC ratio comparing participants who consumed ≥5 sugar-sweetened carbonated beverages per week with nondrinkers was 1.70 (95% CI, 1.03-2.81). This association did not differ by clinical subgroup, including participants at low cardiovascular risk. Our findings suggest that high levels of sugar-sweetened carbonated beverage consumption are associated with a higher prevalence and degree of CAC in asymptomatic adults without a history of cardiovascular disease, cancer, or diabetes. Copyright © 2016 Elsevier Inc. All rights reserved.

  16. Assessment of carbon monoxide values in smokers: a comparison of carbon monoxide in expired air and carboxyhaemoglobin in arterial blood

    DEFF Research Database (Denmark)

    Andersson, Mette F; Møller, Ann M

    2010-01-01

    Smoking increases perioperative complications. Carbon monoxide concentrations can estimate patients' smoking status and might be relevant in preoperative risk assessment. In smokers, we compared measurements of carbon monoxide in expired air (COexp) with measurements of carboxyhaemoglobin (COHb) ......) in arterial blood. The objectives were to determine the level of correlation and to determine whether the methods showed agreement and evaluate them as diagnostic tests in discriminating between heavy and light smokers....

  17. High surface area, high permeability carbon monoliths

    Energy Technology Data Exchange (ETDEWEB)

    Lagasse, R.R.; Schroeder, J.L. [Sandia National Labs., Albuquerque, NM (United States). Organic Materials Processing Dept.

    1994-12-31

    The goal of this work is to prepare carbon monoliths having precisely tailored pore size distribution. Prior studies have demonstrated that poly(acrylonitrile) can be processed into a precursor having tailored macropore structure. Since the macropores were preserved during pyrolysis, this synthetic process provided a route to porous carbon having macropores with size =0.1 to 10{mu}m. No micropores of size <2 nm could be detected in the carbon, however, by nitrogen adsorption. In the present work, the authors have processed a different polymer, poly(vinylidene chloride) into a macroporous precursor, Pyrolysis produced carbon monoliths having macropores derived from the polymer precursor as well as extensive microporosity produced during the pyrolysis of the polymer. One of these carbons had BET surface area of 1,050 m{sup 2}/g and about 1.2 cc/g total pore volume, with about 1/3 of the total pore volume in micropores and the remainder in 1{mu}m macropores. No mesopores in the intermediate size range could be detected by nitrogen adsorption. Carbon materials having high surface area as well as micron size pores have potential applications as electrodes for double layer supercapacitors containing liquid electrolyte, or as efficient media for performing chemical separations.

  18. Heart and Artery Damage and High Blood Pressure

    Science.gov (United States)

    ... Artery Disease Venous Thromboembolism Aortic Aneurysm More How High Blood Pressure Can Lead to a Heart Attack Updated:Dec ... sheet This content was last reviewed October 2016. High Blood Pressure • Home • Get the Facts About HBP • Know Your ...

  19. High resolution ultrasound and arterial wall changes in early atherosclerosis

    Science.gov (United States)

    Renton, Sophie Caroline

    Non-invasive vascular testing evolved initially to meet the needs of the surgeon to identify haemodynamically significant lesions. However, with refinement of techniques and the development of high resolution ultrasound, it has become possible to detect early lesions and to measure the thickness of die arterial wall with an accuracy of 0.2mm. Such measurements have epidemiological and prognostic potential. They may allow the study of progression (or regression) of atherosclerotic disease before symptoms develop. The aim of this thesis was to assess the value of arterial wall measurements of intima-media thickness and compliance of the common carotid artery in the prediction of early atherosclerotic disease. Four different anatomical patterns of carotid bulb morphology have been identified, according to the position of the bulb origin in relation to the flow divider. It has been demonstrated that bulb morphology influences the site of early plaque formation. The presence of plaque at the carotid and femoral bifurcations was found to be associated with increased intima-media thickening of the common carotid artery. Histological analysis of common carotid arteries taken at post-mortem showed that this diffuse intima-media thickening is the result of deposition of cholesterol crystals, medial atrophy, fatty and fibrous change, and accumulation of necrotic debris, the features characteristic of plaques, even though discrete plaques rarely occur at this site. Subsequently, a number of clinical studies were undertaken which demonstrated that the intima-media thickness is increased in diabetics, hypopituitary patients and claudicants as compared to controls. It was found that the intima-media thickness of the common carotid artery could be used to predict the presence of bifurcation plaques and macrovascular disease. The work of this thesis has demonstrated that high resolution ultrasound is a powerful technique for die study of the arterial wall and should be tested in

  20. Novel use of carbon dioxide arteriography in renal artery pseudoaneurysm in patients with poor renal function

    Science.gov (United States)

    Said, Mohammed A; McGuire, Barry B; Liu, Joceline S; Resnick, Scott A; Nadler, Robert B

    2014-01-01

    Renal artery pseudoaneurysm (RAP) is a rare complication of partial nephrectomy, but is usually effectively managed with renal vessel embolisation. We report a particularly challenging case of a patient with chronic kidney disease (CKD) who developed a RAP following a laparoscopic heminephrectomy and was treated using superselective renal vessel coil embolisation with carbon dioxide (CO2) as the primary contrast agent for arteriographic localisation of the RAP and feeder artery. To the best our knowledge we report the first utilisation of CO2 arteriography in the definitive diagnosis and treatment of RAP following heminephrectomy in a patient with severe CKD. PMID:25498109

  1. Level of arterial ligation in rectal cancer surgery: Low tie preferred over high tie. A review

    NARCIS (Netherlands)

    M.M. Lange (Marilyne); M. Buunen (Mark); C.J.H. van de Velde (Cornelis)

    2008-01-01

    textabstractConsensus does not exist on the level of arterial ligation in rectal cancer surgery. From oncologic considerations, many surgeons apply high tie arterial ligation (level of inferior mesenteric artery). Other strategies include ligation at the level of the superior rectal artery, just cau

  2. Effect of High-Calcium Diet on Coronary Artery Disease in Ossabaw Miniature Swine With Metabolic Syndrome.

    Science.gov (United States)

    Phillips-Eakley, Alyssa K; McKenney-Drake, Mikaela L; Bahls, Martin; Newcomer, Sean C; Radcliffe, John S; Wastney, Meryl E; Van Alstine, William G; Jackson, George; Alloosh, Mouhamad; Martin, Berdine R; Sturek, Michael; Weaver, Connie M

    2015-08-13

    Calcium is a shortfall essential nutrient that has been a mainstay of osteoporosis management. Recent and limited findings have prompted concern about the contribution of calcium supplementation to cardiovascular risk. A proposed mechanism is through the acceleration of coronary artery calcification. Determining causality between calcium intake and coronary artery calcification has been hindered by a lack of sensitive methodology to monitor early vascular calcium accumulation. The primary study aim was to assess the impact of high calcium intake on coronary artery calcification using innovative calcium tracer kinetic modeling in Ossabaw swine with diet-induced metabolic syndrome. Secondary end points (in vitro wire myography, histopathology, intravascular ultrasound) assessed coronary disease. Pigs (n=24; aged ≈15 months) were fed an atherogenic diet with adequate calcium (0.33% by weight) or high calcium (1.90% from calcium carbonate or dairy) for 6 months. Following 5 months of feeding, all pigs were dosed intravenously with (41)Ca, a rare isotope that can be measured in serum and tissues at a sensitivity of 10(-18) mol/L by accelerator mass spectrometry. Kinetic modeling evaluated early coronary artery calcification using (41)Ca values measured in serial blood samples (collected over 27 days) and coronary artery samples obtained at sacrifice. Serum disappearance of (41)Ca and total coronary artery (41)Ca accumulation did not differ among groups. Secondary end points demonstrated no treatment differences in coronary artery disease or function. There was no detectable effect of high calcium diets (from dairy or calcium carbonate) on coronary artery calcium deposition in metabolic syndrome swine. © 2015 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley Blackwell.

  3. Carbon-Carbon High Melt Coating for Nozzle Extensions Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The High Melt Coating system is applied to a carbon-carbon structure and embeds HfC, ZrB2 in the outer layers. ACC High Melt builds on the time tested base material...

  4. Bilateral Carotid Artery Dissection after High Impact Road Traffic Accident

    Directory of Open Access Journals (Sweden)

    Michael Kelly

    2008-11-01

    Full Text Available A 58 year old man was involved in a high impact road traffic incident and was admitted for observation. Asymptomatic for the first 24 hours, he collapsed with symptoms and signs consistent with a cerebrovascular accident. Computed tomography angiogram (CTA and Magnetic resonance angiogram (MRA demonstrated bilateral internal carotid artery dissections and a left middle cerebral artery infarct. It was not considered appropriate to attempt stenting or other revascularistation. The patient was treated with heparin prior to starting warfarin. He made a partial recovery and was discharged to a rehabilitation facility. This case is a reminder of carotid dissection as an uncommon but serious complication of high speed motor vehicle accident, which may be silent initially. Literature Review suggests risk stratification before relevant radiological screening at risk patients. Significant advances in CTA have made it the diagnostic tool of choice, but ultrasound is an important screening tool.

  5. Giant, Dissecting, High-Pressure Pulmonary Artery Aneurysm

    Science.gov (United States)

    Smalcelj, Anton; Brida, Vojtjeh; Samarzija, Miroslav; Matana, Ante; Margetic, Eduard; Drinkovic, Niksa

    2005-01-01

    We report the rare subchronic clinical course of a giant, dissecting pulmonary artery aneurysm in an oligosymptomatic middle-aged woman who had idiopathic pulmonary hypertension. Diagnosis was simple with the use of echocardiography and multislice computed tomography. Conversely, deciding on the treatment was difficult, because prominent surgeons declined to perform surgical repair of the aneurysm and recommended heart–lung transplantation. Therefore, we were forced to treat our patient medically. She survived for 1 year, including 8 months of treatment with sildenafil, and then died suddenly while awaiting transplantation. Our patient, who had a dissecting, high-pressure pulmonary artery aneurysm, had an unexpectedly stable and uneventful clinical course for 1 year, which, under more favorable circumstances, might have provided enough time for heart–lung transplantation to be performed. PMID:16429912

  6. Cast Iron With High Carbon Content

    Science.gov (United States)

    Curreri, P. A.; Hendrix, J. C.; Stefanescu, D. M.

    1986-01-01

    Method proposed for solidifying high-carbon cast iron without carbon particles segregating at upper surface. Solidification carried out in low gravity, for example on airplane flying free-fall parabolic trajectory. Many different microstructures obtained by proposed technique, and percentage by weight of carbon retained in melt much higher than at present.

  7. Arterial and end-tidal carbon dioxide difference in pediatric intensive care

    Directory of Open Access Journals (Sweden)

    Chulananda Dias Goonasekera

    2014-01-01

    Full Text Available Background and Aim: Arterial carbon dioxide tension (PaCO 2 is considered the gold standard for scrupulous monitoring in pediatric intensive care unit (PICU, but it is invasive, laborious, expensive, and intermittent. The study aims to explore when we can use end-tidal carbon dioxide tension (P ET CO 2 as a reliable, continuous, and noninvasive monitor of arterial CO 2 Materials and Methods: Concurrent P ET CO 2 , fraction of inspired oxygen, PaCO 2 , and arterial oxygen tension values of clinically stable children on mechanical ventilation were recorded. Children with extra-pulmonary ventriculoatrial shunts were excluded. The P ET CO 2 and PaCO 2 difference and its variability and reproducibility were studied. Results: A total of 624 concurrent readings were obtained from 105 children (mean age [SD] 5.53 [5.43] years requiring invasive bi-level positive airway pressure ventilation in the PICU. All had continuous P ET CO 2 monitoring and an arterial line for blood gas measurement. The mean (SD number of concurrent readings obtained from each child, 4-6 h apart was 6.0 (4.05. The P ET CO 2 values were higher than PaCO 2 in 142 observations (22.7%. The PaCO 2 -P ET CO 2 difference was individual admission specific (ANOVA, P < 0.001. The PaCO 2 -P ET CO 2 difference correlated positively with the alveolar-arterial oxygen tension [P(A-aO 2 ] difference (ρ = 0.381 P < 0.0001. There was a fixed bias between the P ET CO 2 and PaCO 2 measuring methods, difference +0.66 KPa (95% confidence interval: +0.57 to +0.76. Conclusions: The PaCO 2 -P ET CO 2 difference was individual specific. It was not affected by the primary disorder leading to the ventilation.

  8. Accessory brachialis muscle associated with high division of brachial artery

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    Krishnamurthy A

    2010-10-01

    Full Text Available During routine dissection for the undergraduate students in the Department of Anatomy, Kasturba Medical College, Mangalore, of a male cadaver aged 73 years, we encountered an additional slip of brachialis muscle taking origin in the flexor compartment of left arm and inserting into the forearm. The origin of the additional muscle belly was from the anteromedial surface of shaft and medial supracondylar ridge of lower end of humerus. The additional muscle slip merged with the tendon of pronator teres before inserting on the lateral surface of the shaft of radius. The median nerve pierced the muscle at a distance of 6 cm from the medial epicondyle of humerus, supplied it and had a routine course later. Associated with the muscular abnormality was the high division of brachial artery into radial and ulnar arteries 17.5 cm from the medial epicondyle. The ulnar artery passed beneath the accessory brachialis muscle along with the median nerve. The role of additional muscles in compression syndrome is a well known phenomenon. The altered anatomy of the blood vessels may make them more vulnerable to trauma and to hemorrhage but at the same time more accessible for cannulation. Medical fraternity including orthopedicians and neurologists need to be aware of such variations when dealing with upper limb injuries or operations around the elbow joint.

  9. High performance carbon nanocomposites for ultracapacitors

    Science.gov (United States)

    Lu, Wen

    2012-10-02

    The present invention relates to composite electrodes for electrochemical devices, particularly to carbon nanotube composite electrodes for high performance electrochemical devices, such as ultracapacitors.

  10. Physical cleaning of high carbon fly ash

    Energy Technology Data Exchange (ETDEWEB)

    Gray, McMahan L.; Champagne, Kenneth J.; Soong, Yee; Killmeyer, Richard P. [National Energy Technology Laboratory, US Department of Energy, P.O. Box 10940, Cochran Mills Roads, 15236 Pittsburgh, PA (United States); Maroto-Valer, M. Mercedes; Andresen, John M. [The Energy Institute, The Pennsylvania State University, 405 Academic Activities Building, 16802-2308 University Park, PA (United States); Ciocco, Michael V.; Zandhuis, Paul H. [Parson Project Services Inc, National Energy Technology Laboratory, P.O. Box 618, 15129 Library, Pittsburgh, PA (United States)

    2002-04-20

    An industrial fly ash sample was cleaned by three different processes, which were triboelectrostatic separation, ultrasonic column agglomeration, and column flotation. The unburned carbon concentrates were collected at purities ranging up to 62% at recoveries of 62%. In addition, optical microscopy studies were conducted on the final carbon concentrates to determine the carbon forms (inertinite, isotropic coke and anisotropic coke) collected from these various physical-cleaning processes. The effects of the various cleaning processes on the production of different carbon forms from high carbon fly ashes will be discussed.

  11. High capacity carbon dioxide sorbent

    Energy Technology Data Exchange (ETDEWEB)

    Dietz, Steven Dean; Alptekin, Gokhan; Jayaraman, Ambalavanan

    2015-09-01

    The present invention provides a sorbent for the removal of carbon dioxide from gas streams, comprising: a CO.sub.2 capacity of at least 9 weight percent when measured at 22.degree. C. and 1 atmosphere; an H.sub.2O capacity of at most 15 weight percent when measured at 25.degree. C. and 1 atmosphere; and an isosteric heat of adsorption of from 5 to 8.5 kilocalories per mole of CO.sub.2. The invention also provides a carbon sorbent in a powder, a granular or a pellet form for the removal of carbon dioxide from gas streams, comprising: a carbon content of at least 90 weight percent; a nitrogen content of at least 1 weight percent; an oxygen content of at most 3 weight percent; a BET surface area from 50 to 2600 m.sup.2/g; and a DFT micropore volume from 0.04 to 0.8 cc/g.

  12. High speed intravascular photoacoustic imaging of atherosclerotic arteries (Conference Presentation)

    Science.gov (United States)

    Piao, Zhonglie; Ma, Teng; Qu, Yueqiao; Li, Jiawen; Yu, Mingyue; He, Youmin; Shung, K. Kirk; Zhou, Qifa; Kim, Chang-Seok; Chen, Zhongping

    2016-02-01

    Cardiovascular disease is the leading cause of death in the industrialized nations. Accurate quantification of both the morphology and composition of lipid-rich vulnerable atherosclerotic plaque are essential for early detection and optimal treatment in clinics. In previous works, intravascular photoacoustic (IVPA) imaging for detection of lipid-rich plaque within coronary artery walls has been demonstrated in ex vivo, but the imaging speed is still limited. In order to increase the imaging speed, a high repetition rate laser is needed. In this work, we present a high speed integrated IVPA/US imaging system with a 500 Hz optical parametric oscillator laser at 1725 nm. A miniature catheter with 1.0 mm outer diameter was designed with a 200 μm multimode fiber and an ultrasound transducer with 45 MHz center frequency. The fiber was polished at 38 degree and enclosed in a glass capillary for total internal reflection. An optical/electrical rotary junction and pull-back mechanism was applied for rotating and linearly scanning the catheter to obtain three-dimensional imaging. Atherosclerotic rabbit abdominal aorta was imaged as two frame/second at 1725 nm. Furthermore, by wide tuning range of the laser wavelength from 1680 nm to 1770 nm, spectroscopic photoacoustic analysis of lipid-mimicking phantom and an human atherosclerotic artery was performed ex vivo. The results demonstrated that the developed IVPA/US imaging system is capable for high speed intravascular imaging for plaque detection.

  13. Use of venous-to-arterial carbon dioxide tension difference to guide resuscitation therapy in septic shock.

    Science.gov (United States)

    Mallat, Jihad; Lemyze, Malcolm; Tronchon, Laurent; Vallet, Benoît; Thevenin, Didier

    2016-02-04

    The mixed venous-to-arterial carbon dioxide (CO2) tension difference [P (v-a) CO2] is the difference between carbon dioxide tension (PCO2) in mixed venous blood (sampled from a pulmonary artery catheter) and the PCO2 in arterial blood. P (v-a) CO2 depends on the cardiac output and the global CO2 production, and on the complex relationship between PCO2 and CO2 content. Experimental and clinical studies support the evidence that P (v-a) CO2 cannot serve as an indicator of tissue hypoxia, and should be regarded as an indicator of the adequacy of venous blood to wash out the total CO2 generated by the peripheral tissues. P (v-a) CO2 can be replaced by the central venous-to-arterial CO2 difference (ΔPCO2), which is calculated from simultaneous sampling of central venous blood from a central vein catheter and arterial blood and, therefore, more easy to obtain at the bedside. Determining the ΔPCO2 during the resuscitation of septic shock patients might be useful when deciding when to continue resuscitation despite a central venous oxygen saturation (ScvO2) > 70% associated with elevated blood lactate levels. Because high blood lactate levels is not a discriminatory factor in determining the source of that stress, an increased ΔPCO2 (> 6 mmHg) could be used to identify patients who still remain inadequately resuscitated. Monitoring the ΔPCO2 from the beginning of the reanimation of septic shock patients might be a valuable means to evaluate the adequacy of cardiac output in tissue perfusion and, thus, guiding the therapy. In this respect, it can aid to titrate inotropes to adjust oxygen delivery to CO2 production, or to choose between hemoglobin correction or fluid/inotrope infusion in patients with a too low ScvO2 related to metabolic demand. The combination of P (v-a) CO2 or ΔPCO2 with oxygen-derived parameters through the calculation of the P (v-a) CO2 or ΔPCO2/arteriovenous oxygen content difference ratio can detect the presence of global anaerobic metabolism.

  14. Sudden cardiovascular collapse caused by carbon dioxide embolism during endoscopic saphenectomy for coronary artery bypass grafting

    Institute of Scientific and Technical Information of China (English)

    CHEN Xin-chun; TANG Xiao-yang; JIANG Yi-fan; PAN Yan-bing; FU Cheng-zhang

    2006-01-01

    @@ Endoscopic vein harvesting (EVH) for coronary artery bypass grafting (CABG) has gained increasing acceptance as a less invasive alternative to conventional open vein harvesting. With this procedure, carbon dioxide (CO2) is insufflated to create a subcutaneous tunnel to facilitate the harvest of the great saphenous vein. The technique seems to be safe because there are no adverse hemodynamic consequences or systemic CO2 absorption during EVH.1,2 We report a case of massive right heart gas embolism which occurred during a routine EVH performance of the saphenous vein.

  15. Ultrahigh Ductility, High-Carbon Martensitic Steel

    Science.gov (United States)

    Qin, Shengwei; Liu, Yu; Hao, Qingguo; Zuo, Xunwei; Rong, Yonghua; Chen, Nailu

    2016-10-01

    Based on the proposed design idea of the anti-transformation-induced plasticity effect, both the additions of the Nb element and pretreatment of the normalization process as a novel quenching-partitioning-tempering (Q-P-T) were designed for Fe-0.63C-1.52Mn-1.49Si-0.62Cr-0.036Nb hot-rolled steel. This high-carbon Q-P-T martensitic steel exhibits a tensile strength of 1890 MPa and elongation of 29 pct accompanied by the excellent product of tensile and elongation of 55 GPa pct. The origin of ultrahigh ductility for high-carbon Q-P-T martensitic steel is revealed from two aspects: one is the softening of martensitic matrix due to both the depletion of carbon in the matensitic matrix during the Q-P-T process by partitioning of carbon from supersaturated martensite to retained austenite and the reduction of the dislocation density in a martensitic matrix by dislocation absorption by retained austenite effect during deformation, which significantly enhances the deformation ability of martensitic matrix; another is the high mechanical stability of considerable carbon-enriched retained austenite, which effectively reduces the formation of brittle twin-type martensite. This work verifies the correctness of the design idea of the anti-TRIP effect and makes the third-generation advanced high-strength steels extend to the field of high-carbon steels from low- and medium-carbon steels.

  16. High performance hydrophobic solvent, carbon dioxide capture

    Energy Technology Data Exchange (ETDEWEB)

    Nulwala, Hunaid; Luebke, David

    2017-05-09

    Methods and compositions useful, for example, for physical solvent carbon capture. A method comprising: contacting at least one first composition comprising carbon dioxide with at least one second composition to at least partially dissolve the carbon dioxide of the first composition in the second composition, wherein the second composition comprises at least one siloxane compound which is covalently modified with at least one non-siloxane group comprising at least one heteroatom. Polydimethylsiloxane (PDMS) materials and ethylene-glycol based materials have high carbon dioxide solubility but suffer from various problems. PDMS is hydrophobic but suffers from low selectivity. Ethylene-glycol based systems have good solubility and selectivity, but suffer from high affinity to water. Solvents were developed which keep the desired combinations of properties, and result in a simplified, overall process for carbon dioxide removal from a mixed gas stream.

  17. Increased requirement for minute ventilation and negative arterial to end-tidal carbon dioxide gradient may indicate malignant hyperthermia

    Directory of Open Access Journals (Sweden)

    Ho-Tien Lin

    2014-04-01

    Full Text Available Characteristic signs of malignant hyperthermia (MH include unexplained tachycardia, increased end-tidal carbon dioxide (Etco2 concentration, metabolic and respiratory acidosis, and an increase in body temperature above 38.8°C. We present the case of a patient with highly probable MH. In addition to sinus tachycardia and metabolic and respiratory acidosis, this patient also had a negative arterial to Etco2 gradient and an increased requirement for minute ventilation to maintain a normal Etco2 concentration, with signs of increased CO2 production. Despite these signs of MH, the patient's rectal temperature monitoring equipment did not show an increase in temperature, although the temperature measured in the mouth was increased. This case illustrates the unreliability of measuring rectal temperature as a means of reflecting body temperature during MH and the usefulness of increased CO2 production signs in helping to diagnose MH.

  18. Carbon-Carbon High Melt Coating for Nozzle and Nozzle Extensions Project

    Data.gov (United States)

    National Aeronautics and Space Administration — C-CAT, which has proven carbon-carbon fabrication capabilities, will investigate use of ACC-6 High Melt oxidation protective system on carbon-carbon for use on the...

  19. High value carbon materials from PET recycling

    Science.gov (United States)

    Parra, J. B.; Ania, C. O.; Arenillas, A.; Rubiera, F.; Pis, J. J.

    2004-11-01

    Poly(ethylene) terephthalate (PET), has become one of the major post-consumer plastic waste. In this work special attention was paid to minimising PET residues and to obtain a high value carbon material. Pyrolysis and subsequent activation of PET from post-consumer soft-drink bottles was performed. Activation was carried out at 925 °C under CO2 atmosphere to different burn-off degrees. Textural characterisation of the samples was carried out by performing N2 adsorption isotherms at -196 °C. The obtained carbons materials were mainly microporous, presenting low meso and macroporosity, and apparent BET surface areas of upto 2500 m2 g-1. The capacity of these materials for phenol adsorption and PAHs removal from aqueous solutions was measured and compared with that attained with commercial active carbons. Preliminary tests also showed high hydrogen uptake values, as good as the results obtained with high-tech carbon materials.

  20. Magneto-carbonization method for production of carbon fiber, and high performance carbon fibers made thereby

    Energy Technology Data Exchange (ETDEWEB)

    Naskar, Amit K.; Ozcan, Soydan; Eberle, Claude C.; Abdallah, Mohamed Gabr; Mackiewicz, Ludtka Gail; Ludtka, Gerard Michael; Paulauskas, Felix Leonard; Rivard, John Daniel Kennedy

    2017-08-08

    Method for the preparation of carbon fiber from fiber precursor, wherein the fiber precursor is subjected to a magnetic field of at least 3 Tesla during a carbonization process. The carbonization process is generally conducted at a temperature of at least 400.degree. C. and less than 2200.degree. C., wherein, in particular embodiments, the carbonization process includes a low temperature carbonization step conducted at a temperature of at least or above 400.degree. C. or 500.degree. C. and less than or up to 1000.degree. C., 1100.degree. C., or 1200.degree. C., followed by a high temperature carbonization step conducted at a temperature of at least or above 1200.degree. C. In particular embodiments, particularly in the case of a polyacrylonitrile (PAN) fiber precursor, the resulting carbon fiber may possess a minimum tensile strength of at least 600 ksi, a tensile modulus of at least 30 Msi, and an ultimate elongation of at least 1.5%.

  1. Symptomatic isolated middle cerebral artery dissection: High resolution MR findings

    Energy Technology Data Exchange (ETDEWEB)

    Byon, Jung Hee; Kwak, Hyo Sung; Chung, Gyung Ho; Hwang, Seung Bae [Dept. of Radiology, Chonbuk National University Medical School, Jeonju (Korea, Republic of)

    2015-11-15

    To perform high-resolution magnetic resonance imaging (HRMRI) and determine clinical features of patients with acute symptomatic middle cerebral artery (MCA) dissection. Thirteen patients with acute symptomatic MCA dissection underwent HRMRI within 3 days after initial clinical onset. They also underwent routine brain MR imaging. HRMRI examinations included time-of-flight MR angiography (MRA), T2-weighted, T1-weighted, proton-density-weighted, and three-dimensional magnetization-prepared rapid acquisition gradient-echo (MPRAGE) sequences. Conventional angiography and MRA were used as reference standard to establish the diagnosis of MCA dissection. The angiographic findings and HRMRI findings such as intimal flap, double lumen, and intramural hematoma were analyzed in this study. All patients presented cerebral ischemia (median National Institutes of Health Stroke Scale score = 4, range = 0-18). String sign was seen on MRA in seven patients. However, double lumen was seen in all patients on HRMRI by intimal flap. High signal lesion on MPRAGE sequences around the dissection lumen due to intramural hematoma was seen in three patients. HRMRI can be used to easily detect the wall structure of MCA such as the intimal flap and double lumen in patients with acute symptomatic MCA dissection. MPRAGE can detect hemorrhage in false lumen of MCA dissection.

  2. Obesity hypoventilation syndrome in Japan and independent determinants of arterial carbon dioxide levels.

    Science.gov (United States)

    Harada, Yuka; Chihara, Yuichi; Azuma, Masanori; Murase, Kimihiko; Toyama, Yoshiro; Yoshimura, Chikara; Oga, Toru; Nakamura, Hiroshi; Mishima, Michiaki; Chin, Kazuo

    2014-11-01

    Obesity hypoventilation syndrome (OHS) prevalence was previously estimated at 9% in patients with obstructive sleep apnoea (OSA) in Japan. However, the definition of OSA in that study was based on an apnoea-hypopnoea index (AHI) of ≥ 20/h rather than ≥ 5/h. Therefore, the prevalence of OHS in OSA was not measured in the same way as for Western countries. Our study objectives were to investigate the characteristics of Japanese patients with OHS. Nine hundred eighty-one consecutive patients investigated for suspected OSA were enrolled. At least 90% of them were from urban areas, including 162 with obese OSA (body mass index (BMI) ≥ 30 kg/m(2) and AHI ≥ 5/h). The prevalence of OHS (BMI 36.7 ± 4.9 kg/m(2) ) in OSA and that in obese OSA were 2.3% and 12.3%, respectively. Multiple regression analysis revealed that independent of age and BMI, arterial oxygen pressure (contribution rate (R(2) ) = 7.7%), 4% oxygen desaturation index (R(2)  = 8.9%), carbon monoxide diffusing capacity/alveolar volume (R(2)  = 8.3%), haemoglobin concentration (R(2)  = 4.9%) and waist circumference (R(2)  = 4.9%) were independently associated with arterial carbon dioxide pressure. After 12.3 ± 4.6 months of CPAP treatment, more than 60% of OHS patients no longer had hypercapnia. The prevalence of OHS in OSA in Japan was 2.3%. The mean BMI of patients with OHS in Japan was lower than that in Western countries (36.7 kg/m(2) vs 44.0 kg/m(2) ). © 2014 Asian Pacific Society of Respirology.

  3. High origin of a testicular artery: a case report and review of the literature

    Directory of Open Access Journals (Sweden)

    Spyridakis Ioannis

    2011-02-01

    Full Text Available Abstract Introduction Although variations in the origin of the testicular artery are not uncommon, few reports about a high origin from the abdominal aorta exist in the literature. We discuss the case of a high origin of the testicular artery, its embryology, classification systems, and its clinical significance. Case presentation We report a very rare case of high origin of the left testicular artery in a 68-year-old Caucasian male cadaver. The artery originated from the anterolateral aspect of the abdominal aorta, 2 cm cranially to the ipsilateral renal artery. Approximately 1 cm after its origin, it branched off into the inferior suprarenal artery. During its course, the artery crossed anterior to the left renal artery. Conclusions A knowledge of the variant origin of the testicular artery is important during renal and testicular surgery. The origin and course must be carefully identified in order to preserve normal blood circulation and prevent testicular atrophy. A reduction in gonadal blood flow may lead to varicocele under circumstances. A knowledge of this variant anatomy may be of interest to radiologists and helpful in avoiding diagnostic errors.

  4. High frequency conductivity in carbon nanotubes

    Directory of Open Access Journals (Sweden)

    S. S. Abukari

    2012-12-01

    Full Text Available We report on theoretical analysis of high frequency conductivity in carbon nanotubes. Using the kinetic equation with constant relaxation time, an analytical expression for the complex conductivity is obtained. The real part of the complex conductivity is initially negative at zero frequency and become more negative with increasing frequency, until it reaches a resonance minimum at ω ∼ ωB for metallic zigzag CNs and ω < ωB for armchair CNs. This resonance enhancement is indicative for terahertz gain without the formation of current instabilities induced by negative dc conductivity. We noted that due to the high density of states of conduction electrons in metallic zigzag carbon nanotubes and the specific dispersion law inherent in hexagonal crystalline structure result in a uniquely high frequency conductivity than the corresponding values for metallic armchair carbon nanotubes. We suggest that this phenomenon can be used to suppress current instabilities that are normally associated with a negative dc differential conductivity.

  5. Small arteries can be accurately studied in vivo, using high frequency ultrasound

    DEFF Research Database (Denmark)

    Nielsen, T H; Iversen, Helle Klingenberg; Tfelt-Hansen, P

    1993-01-01

    We have validated measurements of diameters of the superficial temporal artery and other small arteries in man with a newly developed 20 MHz ultrasound scanner with A, B and M-mode imaging. The diameter of a reference object was 1.202 mm vs. 1.205 mm as measured by stereomicroscopy (nonsignifican......-gauge plethysmography (nonsignificant). Pulsations were 4.6% in the radial artery. We conclude that high frequency ultrasound provides an accurate and reproducible measure of the diameter of small and medium sized human arteries in vivo....

  6. Correlation of end tidal and arterial carbon dioxide levels in critically Ill neonates and children.

    Science.gov (United States)

    Mehta, Hiren; Kashyap, Rahul; Trivedi, Sangita

    2014-06-01

    End tidal carbon dioxide (EtCO2) monitoring is considered to reflect real-time estimation of partial pressure of carbon dioxide in arterial blood (PaCO2) noninvasively. However, knowledge about its relationship with PaCO2 in critically ill pediatric and neonatal patients is limited. The primary objective was to evaluate predictive capability of end tidal carbon dioxide monitoring and secondary objective was to determine the influence of severity of lung disease on EtCO2 and PaCO2 relationship. This was a prospective, nonrandomized, consecutive enrollment study carried out in neonatal and pediatric intensive care units of a tertiary care children hospital. It was conducted in 66 neonates and 35 children receiving mechanical ventilation. Severity of lung disease was estimated by ventilation index and PaO2/FiO2 (P/F) ratio. Simultaneous recording of EtCO2 and PaCO2 levels was done and data were analyzed for correlation and agreement. In neonates, 150 EtCO2 and PaCO2 pairs were recorded. The mean weight ± SD of patients was 2.1 ± 0.63 kg. PaCO2 had a positive correlation with EtCO2 (r = 0.836, 95% CI = 0.78-0.88). P/F ratio <200 adversely affected relationship. In infants and children, 96 pairs were recorded. Mean age ± SD of patients was 4.20 ± 4.92 years and mean weight ± SD was 13.1 ± 9.49 kg. PaCO2 had an excellent correlation with EtCO2 (r = 0.914, 95% CI = 0.87 and 0.94). P/F ratio <200 adversely affected relationship. EtCO2 monitoring displayed a good validity to predict PaCO2. Correlation was affected by low P/F ratio (<200); hence, it is recommended that blood gases be measured in these patients until such time that a good relation can be established between end tidal and arterial CO2 values.

  7. Effect of treatment temperature on collagen structures of the decellularized carotid artery using high hydrostatic pressure.

    Science.gov (United States)

    Negishi, Jun; Funamoto, Seiichi; Kimura, Tsuyoshi; Nam, Kwangoo; Higami, Tetsuya; Kishida, Akio

    2011-09-01

    Decellularized tissues have attracted a great deal of attention as regenerating transplantation materials. A decellularizing method based on high hydrostatic pressure (HHP) has been developed, and the preparation of many types of decellularized tissues has been investigated, including aorta, cornea, and dermis. The preparation of a small-diameter vascular graft was studied using a carotid artery from the viewpoint of collagen denaturation and leakage. After HHP, the carotid artery was washed at two washing temperatures (37 and 4°C). Histological evaluation, collagen content measurement and circular dichroism (CD) measurement indicated that the washing temperatures clearly affected the collagen structure of the decellularized carotid artery. The amount of collagen decreased in the carotid artery decellularized by HHP washed at 37°C (HHP/37°C). On the other hand, the amount and structure of collagen were preserved in the carotid artery washed at 4°C after HHP (HHP/4°C). In rat carotid artery syngeneic transplantation, the HHP/37°C decellularized carotid artery occluded after 2 weeks, but the HHP/4°C decellularized one did not. These results indicate that collagen denaturation and leakage of the decellularized carotid artery affect the in vivo performance of the carotid artery.

  8. High surface area carbon and process for its production

    Science.gov (United States)

    Romanos, Jimmy; Burress, Jacob; Pfeifer, Peter; Rash, Tyler; Shah, Parag; Suppes, Galen

    2016-12-13

    Activated carbon materials and methods of producing and using activated carbon materials are provided. In particular, biomass-derived activated carbon materials and processes of producing the activated carbon materials with prespecified surface areas and pore size distributions are provided. Activated carbon materials with preselected high specific surface areas, porosities, sub-nm (carbon consumption and metallic potassium intercalation into the carbon lattice during the activation process.

  9. Superconductivity in highly disordered dense carbon disulfide.

    Science.gov (United States)

    Dias, Ranga P; Yoo, Choong-Shik; Struzhkin, Viktor V; Kim, Minseob; Muramatsu, Takaki; Matsuoka, Takahiro; Ohishi, Yasuo; Sinogeikin, Stanislav

    2013-07-16

    High pressure plays an increasingly important role in both understanding superconductivity and the development of new superconducting materials. New superconductors were found in metallic and metal oxide systems at high pressure. However, because of the filled close-shell configuration, the superconductivity in molecular systems has been limited to charge-transferred salts and metal-doped carbon species with relatively low superconducting transition temperatures. Here, we report the low-temperature superconducting phase observed in diamagnetic carbon disulfide under high pressure. The superconductivity arises from a highly disordered extended state (CS4 phase or phase III[CS4]) at ~6.2 K over a broad pressure range from 50 to 172 GPa. Based on the X-ray scattering data, we suggest that the local structural change from a tetrahedral to an octahedral configuration is responsible for the observed superconductivity.

  10. Niflumic Acid Attenuated Pulmonary Artery Tone and Vascular Structural Remodeling of Pulmonary Arterial Hypertension Induced by High Pulmonary Blood Flow In Vivo.

    Science.gov (United States)

    Wang, Kai; Ma, Jianfa; Pang, Yusheng; Lao, Jinquan; Pan, Xuanren; Tang, Qiaoyun; Zhang, Feng; Su, Danyan; Qin, Suyuan; Shrestha, Arnav Prasad

    2015-10-01

    Calcium-activated chloride channels (CaCCs) play a vital role in regulating pulmonary artery tone during pulmonary arterial hypertension (PAH) induced by high blood flow. The role of CaCCs inhibitor niflumic acid (NFA) in vivo during this process requires further investigation. We established the PAH model by abdominal shunt surgery and treated with NFA in vivo. Fifty rats were randomly divided into normal, sham, shunt, NFA group 1 (0.2 mg/kg), and NFA group 2 (0.4 mg/kg). Pathological changes, right ventricle hypertrophy index, arterial wall area/vessel area, and arterial wall thickness/vessel external diameter were analyzed. Then contraction reactions of pulmonary arteries were measured. Finally, the electrophysiological characteristics of pulmonary arterial smooth muscle cells were investigated using patch-clamp technology. After 11 weeks of shunting, PAH developed, accompanied with increased right ventricle hypertrophy index, arterial wall area/vessel area, and arterial wall thickness/vessel external diameter. In the NFA treatment groups, the pressure and pathological changes were alleviated. The pulmonary artery tone in the shunt group increased, whereas it decreased after NFA treatment. The current density of CaCC was higher in the shunt group, and it was decreased in the NFA treatment groups. In conclusion, NFA attenuated pulmonary artery tone and structural remodeling in PAH induced by high pulmonary blood flow in vivo. CaCCs were involved and the augmented current density was alleviated by NFA treatment.

  11. A study of partial pressure of arterial carbon dioxide and end-tidal carbon dioxide correlation in intraoperative and postoperative period in neurosurgical patients

    Science.gov (United States)

    Gaur, Pallavi; Harde, Minal; Gujjar, Pinakin; Deosarkar, Devanand; Bhadade, Rakesh

    2017-01-01

    Background and Aim: Monitoring carbon dioxide (CO2) is of utmost importance in neurosurgical patients. It is measured by partial pressure of arterial CO2 (PaCO2) and end-tidal CO2 (ETCO2). We aimed to study the correlation between PaCO2 and ETCO2 in neurosurgical patients in the intraoperative and postoperative period on mechanical ventilation in Postanesthesia Care Unit (PACU). Methodology: This was prospective observational study done at tertiary care teaching public hospital over a period of 1 year. We studied 30 patients undergoing elective craniotomy intraoperatively and in the postoperative period on mechanical ventilation for 24 h. Serial measurement of ETCO2 and PaCO2 at baseline, hourly intraoperatively and every 6 hourly in the PACU were studied. Data analysis was done using SPSS software version 20. Results: The mean PaCO2–ETCO2 gradient intraoperatively over 4 h is 3.331 ± 2.856 and postoperatively over 24 h is 2.779 ± 2.932 and lies in 95% confidence interval. There was statistically significant correlation between PaCO2 and ETCO2 intraoperatively baseline, 1 h, 2 h, 3 h, and 4 h with Pearson's correlation coefficients of 0.799, 0.522, 0582, 0.439, and 0.547, respectively (P < 0.05). In PACU at baseline, 6 h, 12 h, 18 h, and 24 h Pearson's correlation coefficients were. 534, −0.032, 0.522, 0.242, 0.592, and 0.547, respectively, which are highly significant at three instances (P < 0.01). Conclusion: ETCO2 correlates PaCO2 with acceptable accuracy in neurosurgical patients in the intraoperative and postoperative period on mechanical ventilation in Intensive Care Unit. Thus, continuous and noninvasive ETCO2 can be used as a reliable guide to estimate arterial PCO2 during neurosurgical procedures and in PACU. PMID:28761526

  12. Residual stress in high modulus carbon fibers

    Science.gov (United States)

    Chen, K. J.; Diefendorf, R. J.

    1982-01-01

    The modulus and residual strain in carbon fibers are measured by successively electrochemically milling away the fiber surface. Electrochemical etching is found to remove the carbon fiber surface very uniformly, in contrast to air and wet oxidation. The precision of fiber diameter measurements is improved by using a laser diffraction technique instead of optical methods. More precise diameter measurements reveal that past correlations of diameter and fiber modulus are largely measurement artifact. The moduli of most carbon fibers decrease after the outer layers of the fibers are removed. Owing to experimental difficulties, the moduli and strengths of the fibers at their centers are not determined, and moduli are estimated on the basis of microstructure. The calculated residual stresses are found to be insensitive to these moduli estimates as well as the exact form of regression equation used to describe the moduli and residual strain distributions. Axial compressive residual stresses are found to be very high for some higher modulus carbon fibers. It is pointed out that the compressive stress makes the fibers insensitive to surface flaws when loaded in tension but it may initiate failure by buckling when loaded in compression.

  13. Arterial to end-tidal carbon dioxide difference in children undergoing mechanical ventilation of the lungs during general anaesthesia.

    Science.gov (United States)

    Onodi, C; Bühler, P K; Thomas, J; Schmitz, A; Weiss, M

    2017-07-11

    Capnography (ETCO2 ) is routinely used as a non-invasive estimate of arterial carbon dioxide (PaCO2 ) levels in order to modify ventilatory settings, whereby it is assumed that there is a positive gap between PaCO2 and ETCO2 of approximately 0.5 kPa. However, negative values (ETCO2 > PaCO2 ) can be observed. We retrospectively analysed arterial to end-tidal carbon dioxide differences in 799 children undergoing general anaesthesia with mechanical ventilation of the lungs in order to elucidate predictors for a negative gap. A total of 2452 blood gas analysis readings with complete vital sign monitoring, anaesthesia gas analysis and spirometry data were analysed. Mean arterial to end-tidal carbon dioxide difference was -0.18 kPa (limits of 95% agreement -1.10 to 0.74) and 71.2% of samples demonstrated negative values. The intercept model revealed PaCO2 to be the strongest predictor for a negative PaCO2 -ETCO2 difference. A decrease in PaCO2 by 1 kPa resulted in a decrease in the PaCO2 -ETCO2 difference by 0.23 kPa. This study demonstrates that ETCO2 monitoring in children whose lungs are mechanically ventilated may paradoxically lead to overestimation of ETCO2 (ETCO2 > PaCO2 ) with a subsequent risk of unrecognised hypocarbia. © 2017 The Association of Anaesthetists of Great Britain and Ireland.

  14. Sodium hydrosulfide alleviates pulmonary artery collagen remodeling in rats with high pulmonary blood flow.

    Science.gov (United States)

    Li, Xiaohui; Du, Junbao; Jin, Hongfang; Geng, Bin; Tang, Chaoshu

    2008-11-01

    This study aimed to explore the effect of sodium hydrosulfide (NaHS) on pulmonary artery collagen remodeling in rats with high pulmonary blood flow. Thirty-two Sprague-Dawley rats were randomly divided into a sham group, shunt group, sham + NaHS (an H2S donor) group, and shunt + NaHS group. After 11 weeks of shunting, mean pulmonary artery pressure (MPAP), relative median area (RMA) of pulmonary arteries, H2S concentration in lung tissues, plasma endothelin-1 (ET-1) levels, and ET-1 mRNA in lung tissues were investigated. Collagen I and collagen III were evaluated by immunohistochemistry. Hydroxyproline assay and Sirius-red staining were performed. Matrix metalloproteinase-13 (MMP-13), tissue inhibitor of metalloproteinase-1 (TIMP-1), and connective tissue growth factor (CTGF) were evaluated by immunohistochemistry. After 11 weeks of shunting, rats showed a significant pulmonary hypertension and pulmonary artery collagen remodeling in association with a decrease in lung tissue H2S content. After NaHS treatment for 11 weeks, lung tissue H(2)S content was increased, whereas MPAP was attenuated and RMA was reduced. Meanwhile, pulmonary artery collagen I and collagen III protein expressions of intra-acinar pulmonary arteries were inhibited, but MMP-13/TIMP-1 ratio was augmented with a decreased plasma ET-1 content and lung tissue ET-1mRNA and CTGF expressions. The downregulation of H(2)S is involved in the development of pulmonary artery collagen remodeling induced by high pulmonary blood flow.

  15. High activity carbon sorbents for mercury capture

    Energy Technology Data Exchange (ETDEWEB)

    George G. Stavropoulos; Irene S. Diamantopoulou; George E. Skodras; George P. Sakellaropoulos [Aristotle University of Thessaloniki, Thessaloniki (Greece). Chemical Process Engineering Laboratory

    2006-07-01

    High efficiency activated carbons have been prepared for removing mercury from gas streams. Starting materials used were petroleum coke, lignite, charcoal and olive seed waste, and were chemically activated with KOH. Produced adsorbents were primarily characterized for their porosity by N{sub 2} adsorption at 77K. Their mercury retention capacity was characterized based on the breakthrough curves. Compared with typical commercial carbons, they have exhibited considerably enhanced mercury adsorption capacity. An attempt has been made to correlate mercury entrapment and pore structure. It has been shown that physical surface area is increased during activation in contrast to the mercury adsorption capacity that initially increases and tends to decrease at latter stages. Desorption of active sites may be responsible for this behavior. 10 refs., 3 figs., 1 tab.

  16. High power density carbonate fuel cell

    Energy Technology Data Exchange (ETDEWEB)

    Yuh, C.; Johnsen, R.; Doyon, J.; Allen, J. [Energy Research Corp., Danbury, CT (United States)

    1996-12-31

    Carbonate fuel cell is a highly efficient and environmentally clean source of power generation. Many organizations worldwide are actively pursuing the development of the technology. Field demonstration of multi-MW size power plant has been initiated in 1996, a step toward commercialization before the turn of the century, Energy Research Corporation (ERC) is planning to introduce a 2.85MW commercial fuel cell power plant with an efficiency of 58%, which is quite attractive for distributed power generation. However, to further expand competitive edge over alternative systems and to achieve wider market penetration, ERC is exploring advanced carbonate fuel cells having significantly higher power densities. A more compact power plant would also stimulate interest in new markets such as ships and submarines where space limitations exist. The activities focused on reducing cell polarization and internal resistance as well as on advanced thin cell components.

  17. End tidal carbon dioxide as a predictor of the arterial PCO2 in the emergency department setting

    Science.gov (United States)

    Yosefy, C; Hay, E; Nasri, Y; Magen, E; Reisin, L

    2004-01-01

    Objectives: Patients arriving in the emergency department (ED) need rapid and reliable evaluation of their respiratory status. Mainstream end tidal carbon dioxide (ETCO2) is one of the methods used for this purpose during general anaesthesia of intubated patients in the operating theatre. Sidestream ETCO2 (SSETCO2) might be a non-invasive, rapid, and reliable predictor of arterial PCO2 in non-intubated patients in respiratory distress. The aim of this study was to verify whether SSETCO2 can accurately predict the arterial PCO2 and to detect variables that may affect this correlation. Methods: A prospective semi-blind study. The participants were 73 patients (47 men, 26 women) referred to the ED for respiratory distress. Arterial blood gas pressures and SSETCO2 measurements were performed and recorded for all patients. Other parameters recorded were: age; body temperature; respiratory rate; blood pressure; pulse rate; and medical diagnosis. Results: A significant correlation was found between SSETCO2 and arterial PCO2 (r = 0.792). Compared with the correlation curve of the whole group, age under 50 years deflected the correlation curve to the left, while temperature above 37.6°C deflected it to the right. The rest of the parameters had no clear influence on the SSETCO2/PCO2 correlation curve. Conclusions: There is a good correlation between SSETCO2 and arterial PCO2 in the ED setting. Young age may increase the arterial PCO2/SSETCO2 gradient while raised temperature may decrease this gradient. Further studies are needed to confirm these findings in the normal healthy population. PMID:15333528

  18. Carbon monoxide exposures inside an automobile traveling on an urban arterial highway.

    Science.gov (United States)

    Ott, W; Switzer, P; Willits, N

    1994-08-01

    Carbon monoxide (CO) exposures were measured inside a motor vehicle during 88 standardized drives on a major urban arterial highway, El Camino Real (traffic volume of 30,500-45,000 vehicles per day), over a 13-1/2 month period. On each trip (lasting between 31 and 61 minutes), the test vehicle drove the same 5.9-mile segment of roadway in both directions, for a total of 11.8 miles, passing through 20 intersections with traffic lights (10 in each direction) in three California cities (Menlo Park, Palo Alto, and Los Altos). Earlier tests showed that the test vehicle was free of CO intrusion. For the 88 trips, the mean CO concentration was 9.8 ppm, with a standard deviation of 5.8 ppm. Of nine covariates that were examined to explain the variability in the mean CO exposures observed on the 88 trips (ambient CO at two fixed stations, atmospheric stability, seasonal trend function, time of day, average surrounding vehicle count, trip duration, proportion of time stopped at lights, and instrument type), a fairly strong seasonal trend was found. A model consisting of only a single measure of traffic volume and a seasonal trend component had substantial predictive power (R2 = 0.68); by contrast, the ambient CO levels, although partially correlated with average exposures, contributed comparatively little predictive power to the model. The CO exposures experienced while drivers waited at the red lights at an intersection ranged from 6.8 to 14.9 ppm and differed considerably from intersection to intersection.(ABSTRACT TRUNCATED AT 250 WORDS)

  19. Recrystallization of High Carbon Steel during High Strain Rate

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The recrystallization of high carbon steel during high temperature and high speed rolling has been studied by analyzing the stress-strain curves and the austenite grain size.Isothermal multi-pass hot compression at high strain rate was carried out by Gleeble-2000. The austenite grain size was measured by IBAS image analysis system. The results show that static recrystallization occurred at interpass time under pre-finish rolling, and at the finish rolling stage, due to the brief interpass time, static recrystallization can not be found.

  20. High-pressure Raman spectroscopy of carbon onions and nanocapsules

    Science.gov (United States)

    Guo, J. J.; Liu, G. H.; Wang, X. M.; Fujita, T.; Xu, B. S.; Chen, M. W.

    2009-08-01

    We report high-pressure Raman spectra of carbon onions and nanocapsules investigated by diamond anvil cell experiments. The pressure coefficient and elastic behavior of carbon onions and nanocapsules are found to be very similar to those of multiwall carbon nanotubes. Additionally, detectable structure changes, particularly the collapse of the concentric graphite structure, cannot been seen at pressures as high as ˜20 GPa, demonstrating that carbon onions and nanocapsules have significant hardness and can sustain very high pressures.

  1. Assessment of carbon monoxide values in smokers: a comparison of carbon monoxide in expired air and carboxyhaemoglobin in arterial blood

    DEFF Research Database (Denmark)

    Andersson, Mette F; Møller, Ann M

    2010-01-01

    Smoking increases perioperative complications. Carbon monoxide concentrations can estimate patients' smoking status and might be relevant in preoperative risk assessment. In smokers, we compared measurements of carbon monoxide in expired air (COexp) with measurements of carboxyhaemoglobin (COHb...

  2. High surface area carbon and process for its production

    Energy Technology Data Exchange (ETDEWEB)

    Romanos, Jimmy; Burress, Jacob; Pfeifer, Peter; Rash, Tyler; Shah, Parag; Suppes, Galen

    2016-12-13

    Activated carbon materials and methods of producing and using activated carbon materials are provided. In particular, biomass-derived activated carbon materials and processes of producing the activated carbon materials with prespecified surface areas and pore size distributions are provided. Activated carbon materials with preselected high specific surface areas, porosities, sub-nm (<1 nm) pore volumes, and supra-nm (1-5 nm) pore volumes may be achieved by controlling the degree of carbon consumption and metallic potassium intercalation into the carbon lattice during the activation process.

  3. Influence of Carbon Monoxide on Growth and Apoptosis of Human Umbilical Artery Smooth Muscle Cells and Vein Endothelial Cells

    OpenAIRE

    2012-01-01

    Carbon monoxide (CO) is a vasoactive molecule that is generated by vascular cells as a byproduct of heme catabolism and it plays an important physiological role in circulation system. In order to investigate whether exogenous CO can mediate the growth and proliferation of vascular cells, in this study, we used 250 parts per million (ppm) of CO to treat human umbilical artery smooth muscle cell (hUASMC) and human umbilical vein endothelial cell (HuVEC) and further evaluated the growth and apop...

  4. Coronary CT angiography in clinical triage of patients at high risk of coronary artery disease

    DEFF Research Database (Denmark)

    Kühl, J Tobias; Hove, Jens D; Kristensen, Thomas S

    2017-01-01

    in patients with high likelihood of coronary artery disease and could, in theory, be used to triage high risk patients. As many obstacles remain, including logistical and safety issues, our study does not support the use of CCTA as an additional diagnostic test before ICA in an all-comer NSTEMI population.......%) coronary artery diameter stenosis with a sensitivity, specificity, and positive and negative predictive value of 99%, 81%, 96% and 95%, respectively. CCTA was used to triage patients into guideline defined treatment groups of "no or medical treatment", "referral to percutaneous coronary intervention...

  5. Investigation of arterial gas occlusions. [effect of noncondensable gases on high performance heat pipes

    Science.gov (United States)

    Saaski, E. W.

    1974-01-01

    The effect of noncondensable gases on high-performance arterial heat pipes was investigated both analytically and experimentally. Models have been generated which characterize the dissolution of gases in condensate, and the diffusional loss of dissolved gases from condensate in arterial flow. These processes, and others, were used to postulate stability criteria for arterial heat pipes under isothermal and non-isothermal condensate flow conditions. A rigorous second-order gas-loaded heat pipe model, incorporating axial conduction and one-dimensional vapor transport, was produced and used for thermal and gas studies. A Freon-22 (CHCIF2) heat pipe was used with helium and xenon to validate modeling. With helium, experimental data compared well with theory. Unusual gas-control effects with xenon were attributed to high solubility.

  6. Selective Arterial Embolization in the Treatment of High Flow Priapism: Report of 5 Cases

    Directory of Open Access Journals (Sweden)

    H. Rokni Yazdi

    2005-06-01

    Full Text Available High flow priapism is a rare entity caused by a pathologic influx from lacerated arteries to the cavernous bodies. Transcatheter embolization of feeding arteries is the treatment of choice. We reviewed a series of 5 patients who un derwent transcatheter embolization in our hospital from 2000 to 2004. The mean age of patients was 32 years; dur ation of priapism was between one week and a year. All underwent bilateral pudendal artery ca theterization with No.5 French Cobra-II catheters. We did not microcatheters in our patien ts. Embolized materials were gel-foam, coils and polyvinyl alcohol microspheres. We could follow four of them for 6 to 40 months; one of the patients dropped out from our follow-up study. All the four patients had completed detumescence after a maximum of two days from embolization;none of them experienced signific ant complications and all returned to normal sexual function and remained symptom free thereafter (6-40 months. We noted no difference in complications and duration to restore erectile function and less recurrence rate with embolization of main br anch of pudendal artery instead of superselective embolization of arteriocavernous fistul a feeder artery with a microcatheter that is the method of choice for the treatment of high flow priapism, but due to small number of cases it needs further studies to be confirmed.

  7. Unilateral high origin of facial artery associated with a variant origin of the glandular branch to the submandibular gland

    Directory of Open Access Journals (Sweden)

    Mohandas Rao KG

    2009-11-01

    Full Text Available The variations in the carotid arteries and their branches are common in the anterior triangle of the neck. However, variations in the origin of facial artery and its branches given in the digastric triangle are not very common. A case of high origin of facial artery and abnormal origin of the glandular branch to submandibular gland encountered during routine dissection of anterior triangle of the neck is reported. The facial artery was arising from the external carotid artery deep in the digastric triangle and the glandular branch to submandibular gland was also arising from the external carotid artery about 1 cm below the origin of facial artery in the digastric triangle. Further, the surgical, importance of the case was discussed.

  8. High-strength porous carbon and its multifunctional applications

    Science.gov (United States)

    Wojtowicz, Marek A; Rubenstein, Eric P; Serio, Michael A; Cosgrove, Joseph E

    2013-12-31

    High-strength porous carbon and a method of its manufacture are described for multifunctional applications, such as ballistic protection, structural components, ultracapacitor electrodes, gas storage, and radiation shielding. The carbon is produced from a polymer precursor via carbonization, and optionally by surface activation and post-treatment.

  9. Hyperbaric programs in the United States: Locations and capabilities of treating decompression sickness, arterial gas embolisms, and acute carbon monoxide poisoning: survey results.

    Science.gov (United States)

    Chin, Walter; Jacoby, Laura; Simon, Olivia; Talati, Nisha; Wegrzyn, Gracelene; Jacoby, Rachelle; Proano, Jacob; Sprau, Susan E; Markovitz, Gerald; Hsu, Rita; Joo, Ellie

    2016-01-01

    Hyperbaric oxygen therapy is the primary treatment for arterial gas embolism, decompression sickness and acute carbon monoxide poisoning. Though there has been a proliferation of hyperbaric centers throughout the United States, a scarcity of centers equipped to treat emergency indications makes transport of patients necessary. To locate and characterize hyperbaric chambers capable of treating emergency cases, a survey of centers throughout the entire United States was conducted. Using Google, Yahoo, HyperbaricLink and the UHMS directory, a database for United States chambers was created. Four researchers called clinicians from the database to administer the survey. All centers were contacted for response until four calls went unreturned or a center declined to be included. The survey assessed chamber readiness to respond to high-acuity patients, including staff availability, use of medical equipment such as ventilators and intravenous infusion devices, and responding yes to treating hyperbaric emergencies within a 12-month period. Only 43 (11.9%, N = 361) centers had equipment, intravenous infusion pumps and ventilators, and staff necessary to treat high-acuity patients. Considering that a primary purpose of hyperbaric oxygen therapy is the treatment of arterial gas embolism and decompression sickness, more hyperbaric centers nationwide should be able to accommodate these emergency cases quickly and safely.

  10. High-flow priapism and glans hypervascularization following deep dorsal vein arterialization for vasculogenic impotence.

    Science.gov (United States)

    Wolf, J S; Lue, T F

    1992-01-01

    Microsurgical penile revascularization is becoming an increasingly applied technique in patients with arteriogenic or mixed arteriogenic and venogenic impotence. Deep dorsal vein arterialization has been used successfully in selected patients. Aside from failure of the procedure and the occasional problems associated with vascular surgery, priapism and glans hypervascularization are specific complications of deep dorsal vein arterialization. Priapism in these cases is 'high-flow'; the functional arterial-cavernous fistula can overcome the maintenance of the flaccid state and cause persistent erection. Glans hypervascularization, a syndrome of glans enlargement, skin changes and pain secondary to excessive retrograde filling of the glans penis and corpus spongiosum, can result in urethral compression and glans ulceration. Along with the presentation of the case of a man who suffered both complications, we discuss their pathophysiology, prevention, and treatment.

  11. A Clinical model to identify patients with high-risk coronary artery disease

    NARCIS (Netherlands)

    Y. Yang (Yelin); L. Chen (Li); Y. Yam (Yeung); S. Achenbach (Stephan); M. Al-Mallah (Mouaz); D.S. Berman (Daniel); M.J. Budoff (Matthew); F. Cademartiri (Filippo); T.Q. Callister (Tracy); H.-J. Chang (Hyuk-Jae); V.Y. Cheng (Victor); K. Chinnaiyan (Kavitha); R.C. Cury (Ricardo); A. Delago (Augustin); A. Dunning (Allison); G.M. Feuchtner (Gudrun); M. Hadamitzky (Martin); J. Hausleiter (Jörg); R.P. Karlsberg (Ronald); P.A. Kaufmann (Philipp); Y.-J. Kim (Yong-Jin); J. Leipsic (Jonathon); T.M. LaBounty (Troy); F.Y. Lin (Fay); E. Maffei (Erica); G.L. Raff (Gilbert); L.J. Shaw (Leslee); T.C. Villines (Todd); J.K. Min (James K.); B.J.W. Chow (Benjamin)

    2015-01-01

    textabstractObjectives This study sought to develop a clinical model that identifies patients with and without high-risk coronary artery disease (CAD). Background Although current clinical models help to estimate a patient's pre-test probability of obstructive CAD, they do not accurately identify th

  12. High-density lipoproteins and coronary artery disease: a single-center cohort study

    NARCIS (Netherlands)

    Schaffer, A.; Verdoia, M.; Barbieri, L.; Aprami, T.M.; Suryapranata, H.; Marino, P.; Luca, G.D.

    2014-01-01

    Our goal was to estimate the role of high-density lipoprotein cholesterol (HDL-C) in predicting the prevalence and extent of coronary artery disease (CAD) in 3280 patients undergoing coronary angiography. Predictors of lower HDL levels (<32 mg/dL) were male gender (P < .001), diabetes mellitus

  13. A Clinical model to identify patients with high-risk coronary artery disease

    NARCIS (Netherlands)

    Y. Yang (Yelin); L. Chen (Li); Y. Yam (Yeung); S. Achenbach (Stephan); M. Al-Mallah (Mouaz); D.S. Berman (Daniel); M.J. Budoff (Matthew); F. Cademartiri (Filippo); T.Q. Callister (Tracy); H.-J. Chang (Hyuk-Jae); V.Y. Cheng (Victor); K. Chinnaiyan (Kavitha); R.C. Cury (Ricardo); A. Delago (Augustin); A. Dunning (Allison); G.M. Feuchtner (Gudrun); M. Hadamitzky (Martin); J. Hausleiter (Jörg); R.P. Karlsberg (Ronald); P.A. Kaufmann (Philipp); Y.-J. Kim (Yong-Jin); J. Leipsic (Jonathon); T.M. LaBounty (Troy); F.Y. Lin (Fay); E. Maffei (Erica); G.L. Raff (Gilbert); L.J. Shaw (Leslee); T.C. Villines (Todd); J.K. Min (James K.); B.J.W. Chow (Benjamin)

    2015-01-01

    textabstractObjectives This study sought to develop a clinical model that identifies patients with and without high-risk coronary artery disease (CAD). Background Although current clinical models help to estimate a patient's pre-test probability of obstructive CAD, they do not accurately identify th

  14. Correlation Between Capnography and Arterial Carbon Dioxide Before, During, and After Severe Chest Injury in Swine

    Science.gov (United States)

    2012-01-01

    During phase 2, animals developed decreased oxygenation ( PaO2 :FiO2 [fraction of inspired oxygen] ratio G200) and hy- potension (mean arterial...mercury), ABG, and ratio of arterial oxygen content ( PaO2 ) to FIO2 (PFR). All data col lection was during three phases (1, 2, and 3) of the experiment...did not show an increase in correlation and was therefore left out of the final model. Ratio of PaO2 to FIO2 was not associated with PaCO2. Using

  15. UTERINE ARTERY DOPPLER STUDY FOR PREDICTION OF ADVERSE OUTCOME IN HIGH RISK PREGNANCY

    Directory of Open Access Journals (Sweden)

    Gunjan

    2015-07-01

    Full Text Available AIM : To detect abnormal waveforms in uterine artery in pregnancies at risk between 20 to 24 weeks of gestation and to measure Resistance index (RI and systolic/diastolic ratio(S/D of these waveforms in study population and to study correlation of Doppler dat a with adverse pregnancy outcome. METHODS : This is a prospective study included Doppler analysis of uterine artery waveforms in 107 normotensive women with singleton pregnancy between 20 to24 weeks of period of gestation who were considered to be at increa sed risk of developing pregnancy complications. Women with Multiple gestation, with congenital anomaly of fetus, chronic hypertension, renal disease, cardiac disease, Diabetes Mellitus were excluded from the study. Bilateral uterine artery Doppler was done and Parameters studied were S/D ratio and RI in uterine artery. Early diastolic notch in uterine artery was watched for. The flow velocity waveforms considered abnormal if there was an early diastolic notch in uterine artery in either right or left uterin e artery was watched for abnormal pregnancy outcomes considered are Gestational hypertension, Pre - eclampsia IUGR, Abruptio placentae, IUD and preterm deliveries. RESULTS : minimum women were aged 21 – 25 year with minimum of 18 years and maximum of 36 years, 28% were primigravidae while 72% were multigravidae mean gestational age of which scan was done was 22 wks 1 day (20 - 24 minimum gestational age at time of delivery was 28 wks of gestation 70% women were delivered vaginally and 30% LSCS. 7% women developed Gestational Hypertension, 5% developed Preeclampsia, 8% neonates with IUGR, 3% developed Placental Abruption while 4% had IUD and 8% had Preterm deliveries. CONCLUSION : Abnormal uterine artery Doppler studies in second trimester have been associated with subsequent adverse pregnancy out comes including Preeclampsia IUGR and perinatal mortality. Doppler velocimetry is a primary tool for fetomaternal surveillance in high

  16. Serial measurements of high-sensitivity cardiac troponin T after exercise stress test in stable coronary artery disease

    DEFF Research Database (Denmark)

    Axelsson, Anna; Ruwald, Martin Huth; Dalsgaard, Morten;

    2013-01-01

    The aim was to assess serial measurements of high-sensitivity cardiac troponin T (hs-cTNT) post-exercise in patients with stable coronary artery disease (CAD).......The aim was to assess serial measurements of high-sensitivity cardiac troponin T (hs-cTNT) post-exercise in patients with stable coronary artery disease (CAD)....

  17. High efficient preparation of carbon nanotube-grafted carbon fibers with the improved tensile strength

    Science.gov (United States)

    Fan, Wenxin; Wang, Yanxiang; Wang, Chengguo; Chen, Jiqiang; Wang, Qifen; Yuan, Yan; Niu, Fangxu

    2016-02-01

    An innovative technique has been developed to obtain the uniform catalyst coating on continuously moving carbon fibers. Carbon nanotube (CNT)-grafted carbon fibers with significantly improved tensile strength have been succeeded to produce by using chemical vapor deposition (CVD) when compared to the tensile strength of untreated carbon fibers. The critical requirements for preparation of CNT-grafted carbon fibers with high tensile strength have been found, mainly including (i) the obtainment of uniform coating of catalyst particles with small particle size, (ii) the low catalyst-induced and mechano-chemical degradation of carbon fibers, and (iii) the high catalyst activity which could facilitate the healing and strengthening of carbon fibers during the growth of CNTs. The optimum growth temperature was found to be about 500 °C, and the optimum catalyst is Ni due to its highest activity, there is a pronounced increase of 10% in tensile strength of carbon fibers after CNT growth at 500 °C by using Ni catalyst. Based on the observation from HRTEM images, a healing and crosslink model of neighboring carbon crystals by CNTs has been formulated to reveal the main reason that causes an increase in tensile strength of carbon fibers after the growth of CNTs. Such results have provided the theoretical and experimental foundation for the large-scale preparation of CNT-grafted carbon fibers with the improved tensile strength, significantly promoting the development of CNT-grafted carbon fiber reinforced polymer composites.

  18. Imaging of aortopulmonary collateral arteries with high-resolution multidetector CT

    Energy Technology Data Exchange (ETDEWEB)

    Greil, Gerald F.; Hofbeck, Michael; Sieverding, Ludger [University of Tuebingen, Department of Pediatric Cardiology, Children' s Hospital, Tuebingen (Germany); Schoebinger, Max; Meinzer, Hans-Peter [German Cancer Research Center, Division of Medical and Biological Informatics, Heidelberg (Germany); Kuettner, Axel; Schaefer, Juergen F.; Dammann, Florian; Claussen, Claus D. [University of Tuebingen, Department of Diagnostic Radiology, Tuebingen (Germany)

    2006-06-15

    Precise visualization of the pulmonary vasculature is mandatory for adequate treatment of patients with pulmonary atresia and ventricular septal defect (PA-VSD). Aortopulmonary collateral arteries (APCs) can be visualized by selective injections of contrast agent in the catheterization laboratory. To evaluate multidetector CT (MDCT) and different image postprocessing methods for analysis of complex pulmonary blood supply in patients with PA-VSD. Eight patients (6 weeks to 27.8 years of age) with PA-VSD and APCs underwent MDCT and cardiac catheterization. Using multiplanar reformatting, volume rendering and semiautomatic segmentation algorithms, the aorta, pulmonary arteries and APCs were displayed. MDCT and cardiac catheterization were analyzed by two independent observers. MDCT accurately imaged central pulmonary arteries (n=8), aortopulmonary shunts (n=2), right ventricular to pulmonary artery conduits (n=2) and origin, course and intrapulmonary connections of APCs (n=25), compared to X-ray angiography. A high correlation was found between the MDCT vessel diameter measurements by two independent observers (n=70, r=0.96, P<0.01) and between MDCT and angiographic vessel diameter measurements (n=68, r=0.96, P<0.01). Using three-dimensional imaging software, a complex pulmonary blood supply can be non-invasively and accurately imaged with high-resolution MDCT. This technique may help to reduce the number of cardiac catheterizations or guide interventional or surgical therapy. (orig.)

  19. Raman spectroscopy on carbon nanotubes at high pressure

    OpenAIRE

    Loa, I.

    2003-01-01

    Raman spectroscopy has been the most extensively employed method to study carbon nanotubes at high pressures. This review covers reversible pressure-induced changes of the lattice dynamics and structure of single- and multi-wall carbon nanotubes as well as irreversible transformations induced by high pressures. The interplay of covalent and van-der-Waals bonding in single-wall nanotube bundles and a structural distortion near 2 GPa are discussed in detail. Attempts of transforming carbon nano...

  20. Carbonation Resistance of Sulphoaluminate Cement-based High Performance Concrete

    Institute of Scientific and Technical Information of China (English)

    ZHANG Decheng; XU Dongyu; CHENG Xin; CHEN Wen

    2009-01-01

    The influences of water/cement ratio and admixtures on carbonation resistance of sulphoaluminate cement-based high performance concrete(HPC)were investigated.The experimental results show that with the decreasing water/cement ratio,the carbonation depth of sulphoaluminate cement-based HPC is decreased remarkably,and the carbonation resistance capability is also improved with the adding admixtures.The morphologies and structure characteristics of sulphoaluminate cement hydration products before and after carbonation were analyzed using SEM and XRD.The analysis results reveal that the main hydration product of sulphoaluminate cement,that is ettringite(AFt),de-composes after carbonation.

  1. Preparation of free-standing high quality mesoporous carbon membranes

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xiqing [ORNL; Liang, Chengdu [ORNL; Dai, Sheng [ORNL; Mahurin, Shannon Mark [ORNL; Zhu, Qing [ORNL

    2010-01-01

    Flat-sheet mesoporous carbon membranes with uniform pore size (e.g., 6.4 nm) and controllable thickness were prepared by pyrolysis of polymeric composite films, which were formed by self-assembly of phenolic resin and block copolymer under acidic conditions. Hexamethylenetetramine was selected as a solid cross-linker to control the rheology of polymeric carbon precursors so that the flat-sheet polymeric films could undergo carbonization without deformation, ensuring the preparation of mesoporous carbon membranes on a large scale with high quality. Gas transport properties through these mesoporous carbon membranes are also reported.

  2. Highly oriented carbon nanotube papers made of aligned carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Wang Ding; Song Pengcheng; Liu Changhong; Wu Wei; Fan Shoushan [Tsinghua-Foxconn Nanotechnology Research Center and Department of Physics, Tsinghua University, Beijing 100084 (China)], E-mail: chliu@tsinghua.edu.cn

    2008-02-20

    Paper-like carbon nanotube (CNT) materials have many important applications such as in catalysts, in filtration, actuators, capacitor or battery electrodes, and so on. Up to now, the most popular way of preparing buckypapers has involved the procedures of dispersion and filtration of a suspension of CNTs. In this work, we present a simple and effective macroscopic manipulation of aligned CNT arrays called 'domino pushing' in the preparation of the aligned thick buckypapers with large areas. This simple method can efficiently ensure that most of the CNTs are well aligned tightly in the buckypaper. The initial measurements indicate that these buckypapers have better performance on thermal and electrical conductance. These buckypapers with controllable structure also have many potential applications, including supercapacitor electrodes.

  3. HIGH ARTERIAL BLOOD LACTATE AS SIRS PREDICTOR IN PATIENTS WITH SEVERE HEAD INJURY

    Directory of Open Access Journals (Sweden)

    L Lengkong

    2013-05-01

    Full Text Available Objectives: Lactate is one of the prognostic factor for evaluation of clinical severe head injury patients outcome. Lactate is also known as a factor to support diagnostic and prognosis of SIRS cases. Severe head injury is a head traumatic case frequently found in Emergency Units, where some cases result in mortality. Based on Glasgow Coma Scale (GCS, severe head injury is define as a head injury with GCSscore between 3 and 8. This study aims to determine whether high arterial blood lactate can be used as predictor that causes the occurrence of SIRS.Method: A Cohort prospective study applied in thisresearch to determine arterial blood lactate as a predictor that causes the occurrence of SIRS. This study was conducted at Sanglah General Hospital Bali-Indonesia from May 2013 to July 2013 with 40 patients who fulfilled the inclusive criteria. Data were presented in tables and analyzed by applying Chi Square Test with CI 95% and p <0.05 was considered significant.Results: From 40 samples, 27 were male (62.5% and 17 female (37.5% at the age of 0-10, 2 people (5%, 10-20 years 7 people (17.5%, 20-40 years 14 people (35%, 40-60 years 12 people (30% and over 60 years 5 people (12.5%. On the first day, patients with normal level blood arterial lactate 2 (5%, and high 38 (95% causing SIRS (+ 39 (97.5% and SIRS (- 1 (2.5% samples to occur. Using bivariate analysis between arterial blood lactate level and the amount occurrence of SIRS, we obtain p < 0.05 and variable control using multivariate analysis we obtained variable of liver dysfunction that give significant value with level arterial blood lactate with p < 0.05.Conclusion: From 40 samples of Severe head injury, there were 38 (95% whose blood arterial lactate level increased on the first day, 2 (5% in normal limit and 39 (97.5% with SIRS on the third day when p < 0.05 so that high level arterial blood lactate can be used as predictor that causes SIRS to occur.

  4. Electrochemical Hydrogen Storage in a Highly Ordered Mesoporous Carbon

    Directory of Open Access Journals (Sweden)

    Dan eLiu

    2014-10-01

    Full Text Available A highly order mesoporous carbon has been synthesized through a strongly acidic, aqueous cooperative assembly route. The structure and morphology of the carbon material were investigated using TEM, SEM and nitrogen adsorption-desorption isotherms. The carbon was proven to be meso-structural and consisted of graphitic micro-domain with larger interlayer space. AC impedance and electrochemical measurements reveal that the synthesized highly ordered mesoporous carbon exhibits a promoted electrochemical hydrogen insertion process and improved capacitance and hydrogen storage stability. The meso-structure and enlarged interlayer distance within the highly ordered mesoporous carbon are suggested as possible causes for the enhancement in hydrogen storage. Both hydrogen capacity in the carbon and mass diffusion within the matrix were improved.

  5. VASOMOTOR ENDOTHELIAL FUNCTION AND MICROCIRCULATION IN ELDERLY PATIENTS WITH ISOLATED SYSTOLIC ARTERIAL HYPERTENSION: INFLUENCE OF "DRY" CARBONIC BATHS AND GENERAL LOW-FREQUENCY MAGNETOTHERAPY

    OpenAIRE

    Alypova, Elena

    2013-01-01

    Abstract. The comparative estimation of influence of the general low-frequency magnetotherapy (GLMT) and "dry" carbonic baths (DCB) on indicators of vasomotor endothelial function and microcirculation in elderly patients with isolated systolic (ISAH) arterial hypertension has been studied. The efficiency of application the combined use of the GLMT and "dry" carbonic baths DCB for correction of revealed disorders in comparing to the monovariant use of thees medical physical factors is establis...

  6. Artery wall layer dimensions during normal pregnancy: a longitudinal study using noninvasive high-frequency ultrasound.

    Science.gov (United States)

    Akhter, Tansim; Larsson, Anders; Larsson, Marita; Wikström, Anna-Karin; Naessen, Tord

    2013-01-15

    The vascular effects of normal pregnancy were investigated by estimating the intima and media thicknesses of the common carotid artery separately using 22-MHz ultrasound (Collagenoson, Meudt, Germany) in 57 healthy women with normal pregnancies and pregnancy outcomes, in all three trimesters and at 1 yr postpartum. A thick intima, thin media, and high intima-to-media (I/M) ratio are signs of a less healthy artery wall. Mean artery wall layer dimensions remained fairly constant during pregnancy, but the intima thickness and I/M thickness ratio appeared to improve (decrease) postpartum (P blood pressure in the first trimester were associated with higher I/M ratios, especially in the second trimester, whereas higher serum estradiol levels were significantly associated with a lower I/M ratio. Changes from the first to second trimesters in I/M ratio, taking into account differential changes in intima and media thickness, were significantly (P pregnancy appeared to improve postpartum. However, higher age, body mass index, or blood pressure and lower serum estradiol levels in the first trimester appeared to negatively affect the artery wall, strongly suggesting that pregnancy has negative vascular effects in some women. A less likely explanation involves possible adaptation to physiological changes during and after pregnancy.

  7. STRUCTURE AND CHARACTERISTICS OF PATENTED HIGH-CARBON WIRE

    Directory of Open Access Journals (Sweden)

    A. Ju. Borisenko

    2011-01-01

    Full Text Available The influence of bainite structure on mechanical characteristics of wire of steel 80 after patenting is studied. The quantity and structure state of bainite, providing high complex of mechanical characteristics of high-carbon wire, is determined.

  8. STRUCTURE AND PROPERTIES OF PATENTED HIGH-CARBON WIRE

    Directory of Open Access Journals (Sweden)

    A. Yu. Borisenko

    2012-01-01

    Full Text Available The influence of bainite structure on mechanical characteristics of wire of steel 80 after patenting is studied. The quantity and structure state of bainite, providing high complex of mechanical characteristics of high-carbon wire, is determined.

  9. The relationship between arterial carbon dioxide tension and end-tidal carbon dioxide tension in intubated adults with traumatic brain injuries who required emergency craniotomies.

    Science.gov (United States)

    Dyer, Brett A; White, William A; Lee, Doohee; Elkins, Laurie; Slayton, Donna J

    2013-01-01

    Anesthetic management of patients who have suffered traumatic brain injuries can be challenging. We investigated the relationship between arterial to end-tidal carbon dioxide partial pressure gradients (Pa-etCO₂) and 3 predictor variables: (1) injury severity score, (2) use of positive end-expiratory pressure, and (3) presence of rib fractures. Using a convenient sampling method, we sampled 56 patients who arrived to the operating room intubated after traumatic brain injuries between 2005 and 2011. Two groups were compared retrospectively: those with Pa-etCO₂ greater than 10 mm Hg (case group) (n = 37) and those with Pa-etCO₂ gradients of 10 mm Hg or less (control group) (n = 19). Descriptive and inferential statistics were employed to identify any differences between the groups. Stepwise regression was also performed. Cross tabulation analysis revealed that injury severity score of 30 or more was a predictor of Pa-etCO₂ gradient. Stepwise regression analysis revealed the presence of rib fracture and body mass index to be significant predictors of Pa-etCO₂ gradient (P arterial blood gas analysis to determine optimal ventilation status of these patients.

  10. Low WSS and High OSI Measured by 3D Cine PC MRI Reflect High Pulmonary Artery Pressures in Suspected Secondary Pulmonary Arterial Hypertension.

    Science.gov (United States)

    Terada, Masaki; Takehara, Yasuo; Isoda, Haruo; Uto, Tomohiro; Matsunaga, Masaki; Alley, Marcus

    2016-01-01

    Institutional Review Board (IRB)-approved prospective study was conducted to test whether objective and quantitative hemodynamic markers wall shear stress (WSS) and oscillatory shear index (OSI) measured by three-dimensional (3D) cine phase-contrast (PC) can reflect pulmonary arterial hypertension (PAH). Seventeen consecutive patients of suspected secondary PAH were examined for pulmonary artery pressures (PAPs) with right heart catheterization (RHC) and three-dimensional (3D) cine PC MR. Based on the RHC data, patients were subdivided into two groups of 12 non-PAH (median age of 74.5 years) and 5 PAH (median age of 77 years) patients. Based on 3D cine PC magnetic resonance (MR), hemodynamic parameters including spatially averaged systolic WSS (sWSS), diastolic WSS (dWSS), mean WSS (mWSS), OSI and blood vessel section area (BVSA) at the pulmonary arterial trunk were calculated. Streamline images in the pulmonary arteries were also assessed. All the parameters were compared between non-PAH and PAH groups. sWSS (N/m(2)) and mWSS (N/m(2)) of PAH group was lower than that of non-PAH group (0.594 ± 0.067 vs. 0.961 ± 0.590, P = 0.001), (0.365 ± 0.035 vs. 0.489 ± 0.132, P = 0.027). OSI of PAH group was higher than that of non-PAH (0.214 ± 0.026 vs. 0.130 ± 0.046, P = 0.001). sWSS, mWSS, and dWSS were inversely correlated and OSI was positively correlated to mean PAP or systolic PAP with r values of -0.638 (P = 0.005), -0.643 (P = 0.005), -0.485 (P = 0.049), and 0.625 (P = 0.007); or -0.622 (P = 0.008), -0.629 (P = 0.007), -0.484 (P = 0.049), and 0.594 (P = 0.012), respectively. sWSS was also inversely correlated to BVSA with r value of -0.488 (P = 0.049), and OSI was correlated to BVSA with r value of 0.574 (P = 0.016). Vortex or helical flows were observed more frequently in PAH patients. The low sWSS and mWSS as well as high OSI measured with 3D cine PC MR could be potential hemodynamic markers for the increased PAP in suspected secondary PAH patients.

  11. In vivo measurement of intracellular pH in human brain during different tensions of carbon dioxide in arterial blood. A 31P-NMR study

    DEFF Research Database (Denmark)

    Jensen, K E; Thomsen, C; Henriksen, O

    1988-01-01

    The effect of changes in carbon dioxide tension in arterial blood upon intracellular pH in brain tissue was studied in seven healthy volunteers, aged 22-45 years. The pH changes were monitored by use of 31P nuclear magnetic resonance spectroscopy, performed on a whole-body 1.5 Tesla Siemens imaging...

  12. Urban ectopy in the mountains: Carbon monoxide exposure at high altitude

    Energy Technology Data Exchange (ETDEWEB)

    Leaf, D.A. [Univ. of California Medical Center, Los Angeles, CA (United States); Kleinman, M.T. [Univ. of California, Irvine, CA (United States)

    1996-07-01

    Environmental exposure to inhaled carbon monoxide (CO) increases coronary artery disease risk. Sudden cardiac death, a frequent manifestation of coronary artery disease, is usually a result of ventricular dysrhythmia. The effect of exposure to CO at sea level (CO/SL) and simulated high (2.1 km) altitudes (CO/HA) on the incidence of cardiac ectopy in subjects with coronary artery disease was investigated. A double-blind crossover study was conducted, with random-order assignment, and each subject served as his own control. Seventeen men with documented coronary artery disease and stable angina pectoris performed cardiopulmonary exercise stress tests after random exposure to either CO or clean air (CA) at sea level (CA/SL) or at a simulated 2.1-km high altitude (CA/HA). The individual CO and HA exposure conditions were each selected to reduce the percentage of oxygen saturation of the subjects arterial blood by 4%. Subjects blood carboxyhemoglobin levels were increased form an average of 0.62% after clean-air exposure to 3.91% of saturation after CO exposure. The percentage of oxygen saturation in arterial blood was reduced from a baseline level of 98% to approximately 94% after CO/SL or CA/HA and to approximately 90% after CO/HA. Compared with the CA/SL the average incidence of exercise-induced ventricular ectopy was approximately doubled after all exposures and a significant trend (p {le} .05) of increased ectopy with decreased oxygen saturation in arterial blood was observed. Yet, among subjects who were free from ectopy (n=11) on CA/SL, only 2 subjects developed ectopy after CO/HA. No episodes of ventricular tachycardia or fibrillation occurred. The findings indicated that exposure to increased levels of hypoxemia, resulting from hypoxic and/or CO exposures, increased the susceptibility to ventricular ectopy during exercise in individuals with stable angina pectoris; however, this risk was nominal for those without ectopy. 26 refs., 1 fig., 2 tabs.

  13. CARBON FIBER COMPOSITES IN HIGH VOLUME

    Energy Technology Data Exchange (ETDEWEB)

    Warren, Charles David [ORNL; Das, Sujit [ORNL; Jeon, Dr. Saeil [Volvo Trucks North America

    2014-01-01

    Vehicle lightweighting represents one of several design approaches that automotive and heavy truck manufacturers are currently evaluating to improve fuel economy, lower emissions, and improve freight efficiency (tons-miles per gallon of fuel). With changes in fuel efficiency and environmental regulations in the area of transportation, the next decade will likely see considerable vehicle lightweighting throughout the ground transportation industry. Greater use of carbon fiber composites and light metals is a key component of that strategy. This paper examines the competition between candidate materials for lightweighting of heavy vehicles and passenger cars. A 53-component, 25 % mass reduction, body-in-white cost analysis is presented for each material class, highlighting the potential cost penalty for each kilogram of mass reduction and then comparing the various material options. Lastly, as the cost of carbon fiber is a major component of the elevated cost of carbon fiber composites, a brief look at the factors that influence that cost is presented.

  14. Comparison of thermal damage of the internal thoracic artery using ultra high radiofrequency and monopolar diathermy.

    Science.gov (United States)

    Bulat, Cristijan; Pešutić-Pisac, Valdi; Capkun, Vesna; Marović, Zlatko; Pogorelić, Zenon; Družijanić, Nikica

    2014-10-01

    The internal thoracic artery (ITA) has been accepted worldwide as a first choice conduit for myocardial revascularisation. It still remains questionable what is the best method for ITA harvesting in a skeletonized fashion according to structural integrity of artery, as a risk factor of early and late graft failure. The purpose of this study was to determine the impact of the ultra-high radiofrequency energy used for ITA harvesting on arterial structural integrity, in particular on the endothelial layer. Seventy-four ITA specimens were divided into two groups depending on device used for harvesting (radiofrequency-knife (RF) or electrocauter (EC)). Thermal damage on arterial structural integrity was measured using light microscope, morphometric imaging analysis and immunohistochemical methods. Thermal damage of endothelium was 2.8 times higher in EC than in RF group (p = 0.041) and 5 times higher in patients older than 66 years of age (p = 0.002). Extent of endothelial damage (graded from 0 to 3) was significantly higher in EC group (p = 0.03). Also, in EC group, in patients older than 66 years of age higher proportion of extent of endothelial damage was found (p = 0.027). The endothelial damage was more often in EC than in RF group as in the patients older than 66 years of age. Demonstrated results suggest that the radiosurgery in comparison to conventional electrocautery is safe and effective method, and significantly reduces thermal damage to endothelial layer of artery. Copyright © 2013 Royal College of Surgeons of Edinburgh (Scottish charity number SC005317) and Royal College of Surgeons in Ireland. Published by Elsevier Ltd. All rights reserved.

  15. High resolution wavenumber analysis for investigation of arterial pulse wave propagation

    Science.gov (United States)

    Hasegawa, Hideyuki; Sato, Masakazu; Irie, Takasuke

    2016-07-01

    The propagation of the pulse wave along the artery is relatively fast (several m/s), and a high-temporal resolution is required to measure pulse wave velocity (PWV) in a regional segment of the artery. High-frame-rate ultrasound enables the measurement of the regional PWV. In analyses of wave propagation phenomena, the direction and propagation speed are generally identified in the frequency-wavenumber space using the two-dimensional Fourier transform. However, the wavelength of the pulse wave is very long (1 m at a propagation velocity of 10 m/s and a temporal frequency of 10 Hz) compared with a typical lateral field of view of 40 mm in ultrasound imaging. Therefore, PWV cannot be identified in the frequency-wavenumber space owing to the low resolution of the two-dimensional Fourier transform. In the present study, PWV was visualized in the wavenumber domain using phases of arterial wall acceleration waveforms measured by high-frame-rate ultrasound.

  16. High-resolution Magnetic Resonance Vessel Wall Imaging for Intracranial Arterial Stenosis

    Institute of Scientific and Technical Information of China (English)

    Xian-Jin Zhu; Wu Wang; Zun-Jing Liu

    2016-01-01

    Objective:To discuss the feasibility and clinical value of high-resolution magnetic resonance vessel wall imaging (HRMR VWI) for intracranial arterial stenosis.Date Sources:We retrieved information from PubMed database up to December 2015,using various search terms including vessel wall imaging (VWI),high-resolution magnetic resonance imaging,intracranial arterial stenosis,black blood,and intracranial atherosclerosis.Study Selection:We reviewed peer-reviewed articles printed in English on imaging technique of VWI and characteristic findings of various intracranial vasculopathies on VWI.We organized this data to explain the value of VWI in clinical application.Results:VWI with black blood technique could provide high-quality images with submillimeter voxel size,and display both the vessel wall and lumen of intracranial artery simultaneously.Various intracranial vasculopathies (atherosclerotic or nonatherosclerotic) had differentiating features including pattern of wall thickening,enhancement,and vessel remodeling on VWI.This technique could be used for determining causes of stenosis,identification of stroke mechanism,risk-stratifying patients,and directing therapeutic management in clinical practice.In addition,a new morphological classification based on VWI could be established for predicting the efficacy of endovascular therapy.Conclusions:This review highlights the value of HRMR VWI for discrimination of different intracranial vasculopathies and directing therapeutic management.

  17. Increased wall tension in response to vasoconstrictors in isolated mesenteric arterial rings from patients with high blood pressure.

    Science.gov (United States)

    Tahvanainen, Anna; Taurio, Jyrki; Mäki-Jouppi, Jenni; Kööbi, Peeter; Mustonen, Jukka; Kähönen, Mika; Sand, Juhani; Nordback, Isto; Pörsti, Ilkka

    2006-12-01

    Essential hypertension is associated with several alterations in arterial function. A wealth of information from animal models is available concerning hypertensive changes in the mesenteric circulation, while only few studies have examined human mesenteric arterial function. The tone of isolated mesenteric arterial segments (outer diameter 0.7-0.9 mm) was examined from individuals with high (n=17) or normal (n=22) blood pressure, grouped using the current definition of elevated blood pressure (140/90 mmHg). Since the majority of them were operated because of malignancies, we evaluated whether functional vascular properties provided information about patient prognosis. Wall tension development (mN/mm) in response to vasoconstrictors (noradrenaline, 5-hydroxy tryptamine, potassium chloride) was higher in mesenteric arterial rings from patients with high than normal blood pressure. There was no difference in vasoconstrictor sensitivity, or endothelium-dependent and endothelium-independent vasorelaxation. Arterial segment weight was higher in hypertensive subjects, suggesting vascular wall hypertrophy. The 10-year follow-up showed no differences in the control of arterial tone between the surviving (n=14) or deceased (n=25) patients. In conclusion, isolated mesenteric arterial segments from hypertensive patients showed increased wall tension in response to vasoconstrictors. Since the mesenteric circulation is an important regulator of peripheral arterial resistance, possible functional alterations in this vascular bed should be further investigated in hypertensive patients.

  18. ARTERIAL STIFFNESS PARAMETERS IN PATIENTS WITH MODERATE/HIGH CARDIOVASCULAR RISK DURING LISINOPRIL AND SIMVASTATIN TREATMENT

    Directory of Open Access Journals (Sweden)

    V. N. Isakova

    2016-01-01

    Full Text Available Aim. To evaluate parameters of arterial stiffness by non-invasive arteriography in patients with moderate/high cardiovascular risk receiving lisinopril and simvastatin.Material and methods. 20 patients (aged 50-55 y.o. with arterial hypertension of the 1st degree and dislipidemia are included in the study. All patients had pulse wave velocity (PWV ≥ 10 m/s and/or the corrected index of pulse wave augmentation (AI × 80 ≥ -10% according to non-invasive arteriography data; and moderate-high cardiovascular risk (≥ 3%. Patients received therapy with lisinopril and simvastatin. Blood pressure (BP levels and lipid profiles were assessed before therapy and in 1, 2, 6 and 12 month of the observation. Non-invasive arteriography was performed before therapy and in 2, 6 and 12 months later.Results. BP target levels were reached within 1 month of treatment as well as improvement of lipid profile was reached within 2 months in majority of the patients. Reference PWV and AI were reached in 85,7% of patients within one year of treatment.Conclusion. Arterial stiffness parameters help to evaluate cardiovascular risk changes accurately as the results of treatment.

  19. Oxidative modification of high density lipoprotein induced by cultured human arterial smooth muscle cells

    Institute of Scientific and Technical Information of China (English)

    江渝; 刘红; 彭家和; 叶治家; 何凤田; 董燕麟; 刘秉文

    2003-01-01

    Objective: To observe the oxidative modification of high density lipoprotein (HDL) induced by cultured human arterial smooth muscle cells (SMCs). Methods: HDL cocultured with SMCs at 37℃ in 48 h was subjected, and native HDL (N-HDL) served as control. Oxidative modification of HDL was identified by using agarose gel electrophoresis. Absorbances of conjugated diene (CD) and lipid hydroperoxide (LOOH) were measured with ultraviolet spectrophotometry at 234 and 560 nm respectively, and fluorescence intensity of thiobarbuturic acid reaction substance (TBARS) with fluorescence spectrophotometry at 550 nm emission wavelength with excitation at 515 nm. Results: In comparison with N-HDL, the electrophoretic mobility of SMCs-cocultured HDL was increased, and the contents of CD, LOOH and TBARS HDL were very significantly higher than those of the control HDL (P<0.01). Conclusion: Oxidative modification of HDL can be induced by human arterial SMCs.

  20. Giant, dissecting, high-pressure pulmonary artery aneurysm: case report of a 1-year natural course.

    Science.gov (United States)

    Smalcelj, Anton; Brida, Vojtjeh; Samarzija, Miroslav; Matana, Ante; Margetic, Eduard; Drinkovic, Niksa

    2005-01-01

    We report the rare subchronic clinical course of a giant, dissecting pulmonary artery aneurysm in an oligosymptomatic middle-aged woman who had idiopathic pulmonary hypertension. Diagnosis was simple with the use of echocardiography and multislice computed tomography. Conversely, deciding on the treatment was difficult, because prominent surgeons declined to perform surgical repair of the aneurysm and recommended heart-lung transplantation. Therefore, we were forced to treat our patient medically. She survived for 1 year, including 8 months of treatment with sildenafil, and then died suddenly while awaiting transplantation. Our patient, who had a dissecting, high-pressure pulmonary artery aneurysm, had an unexpectedly stable and uneventful clinical course for 1 year, which, under more favorable circumstances, might have provided enough time for heart-lung transplantation to be performed.

  1. Capsaicin, arterial hypertensive crisis and acute myocardial infarction associated with high levels of thyroid stimulating hormone.

    Science.gov (United States)

    Patanè, Salvatore; Marte, Filippo; Di Bella, Gianluca; Cerrito, Marco; Coglitore, Sebastiano

    2009-05-01

    Chili peppers are rich in capsaicin. The potent vasodilator calcitonin gene-related peptide (CGRP) is stored in a population of C-fiber afferents that are sensitive to capsaicin. CGRP and peptides released from cardiac C fibers have a beneficial effect in myocardial ischemia and reperfusion. It has been reported that capsaicin pretreatment deplete cardiac C-fiber peptide stores. Furthermore, it has also been reported that capsaicin-treated pigs significantly increase mean arterial blood pressure compared with controls and that the decrease in CGRP synthesis and release contributes to the elevated blood pressure. It has also been reported that sub-clinical hypothyroidism is associated with a significant risk of coronary heart disease (CHD). We present a case of arterial hypertensive crisis and acute myocardial infarction in a 59-year-old Italian man with high levels of thyroid stimulating hormone and with an abundant ingestion of peppers and of chili peppers which occurred the day before.

  2. High-Conductance Thermal Interfaces Based on Carbon Nanotubes Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose to develop a novel thermal interface material (TIM) that is based on an array of vertical carbon nanotubes (CNTs) for high heat flux applications. For...

  3. Endovascular treatment of the subclavian artery aneurysm in high-risk patient - a single-center experience

    Directory of Open Access Journals (Sweden)

    Marjanović Ivan

    2016-01-01

    Full Text Available We present our first experience with endovascular treatment of 6 subclavian artery aneurysms (SAA occurring in five male and one female patient. All patients, in our studies, according to ASA classification were high risk for open repair of SAA. The etiology of the all aneurysms was atherosclerosis degeneration of the artery. Two aneurysms were of intrathoracic location, then the other were extrathoracic. Symptoms related to subclavian artery aneurysms were present in two patients, compression and chest pain in one, and hemorrhage shock in second, while the remaining patients were asymptomatic. We preferred the Viabhan endoprosthesis for endovascular repair in 5 cases. In one patient with ruptured of subclavian artery aneurysm who was high-risk for open repair we made combined endovascular procedure. First at all, we covered the origin of left subclavian artery with thoracic stent graft and after that we put two coils in proximal part of subclavian artery. There was no operative mortality, and the early patency rate was 100%. The follow-up period was from 3 months to 3 years. During this period, one patient died of heart failure and one patient required endovascular reoperation due to endoleak type I. Endovascular treatment is recommended for all patients with subclavian artery aneurysm whenever this is possible due to anatomical reasons especially in high-risk patient with intrathoracic localization of aneurysm, to prevent potential complications.

  4. The giraffe kidney tolerates high arterial blood pressure by high renal interstitial pressure and low glomerular filtration rate

    DEFF Research Database (Denmark)

    Damkjær, Mads; Wang, T; Brøndum, E

    2015-01-01

    BACKGROUND: The tallest animal on earth, the giraffe (Giraffa camelopardalis) is endowed with a mean arterial blood pressure (MAP) twice that of other mammals. The kidneys reside at heart level and show no sign of hypertension-related damage. We hypothesized that a species-specific evolutionary...... on body mass. A strong renal capsule supports a RIHP, which is >10-fold that of other mammals effectively reducing the net filtration pressure and protecting against the high MAP....... renal plasma flow (ERPF). Renal interstitial hydrostatic pressure (RIHP) was assessed by inserting a needle into the medullary parenchyma. Doppler ultrasound measurements provided renal artery resistive index (RI). Hormone concentrations as well as biomechanical, structural and histological...

  5. Biodegradation of pitch-based high performance carbon fibers

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, T. (Yamaguchi Univ., Yamaguchi, (Japan). Faculty of Education)

    1992-09-10

    Although carbon fibers are widely used in various purposes because of their excellent mechanical properties, their behavior under biodegradation by microorganisms has not been elucidated. To elucidate the process of biodegradation of carbon fibers is important for understanding thoroughly the durability and the functionality of the fibers. In this article, a study has been made on biodegradation of pitch-based high performance carbon fibers by microorganisms. The fiber which was degraded has been examined with a scanning electron microscope. Aspergillus flavus has broken surface areas of high performance carbon fibers in 60 days and the fibril structure under the surface layer of the fiber has been exfoliated by degradation. The fibrils on the second layer have been 100-110nm wide. The fibrils have been in line nearly parallel to the fiber axis. The above carbon fibers are carbon type, but in case of graphite type high performance carbon fibers, its broken areas have not been shown and they have shown much stronger resistance against microbial attacks. 11 refs., 8 figs., 2 tabs.

  6. Carbonic anhydrase inhibitors modify intracellular pH transients and contractions of rat middle cerebral arteries during CO2/HCO3(-) fluctuations.

    Science.gov (United States)

    Rasmussen, Jacob K; Boedtkjer, Ebbe

    2017-01-01

    The CO2/HCO3(-) buffer minimizes pH changes in response to acid-base loads, HCO3(-) provides substrate for Na(+),HCO3(-)-cotransporters and Cl(-)/HCO3(-)-exchangers, and H(+) and HCO3(-) modify vasomotor responses during acid-base disturbances. We show here that rat middle cerebral arteries express cytosolic, mitochondrial, extracellular, and secreted carbonic anhydrase isoforms that catalyze equilibration of the CO2/HCO3(-) buffer. Switching from CO2/HCO3(-)-free to CO2/HCO3(-)-containing extracellular solution results in initial intracellular acidification due to hydration of CO2 followed by gradual alkalinization due to cellular HCO3(-) uptake. Carbonic anhydrase inhibition decelerates the initial acidification and attenuates the associated transient vasoconstriction without affecting intracellular pH or artery tone at steady-state. Na(+),HCO3(-)-cotransport and Na(+)/H(+)-exchange activity after NH4(+)-prepulse-induced intracellular acidification are unaffected by carbonic anhydrase inhibition. Extracellular surface pH transients induced by transmembrane NH3 flux are evident under CO2/HCO3(-)-free conditions but absent when the buffer capacity and apparent H(+) mobility increase in the presence of CO2/HCO3(-) even after the inhibition of carbonic anhydrases. We conclude that (a) intracellular carbonic anhydrase activity accentuates pH transients and vasoconstriction in response to acute elevations of pCO2, (b) CO2/HCO3(-) minimizes extracellular surface pH transients without requiring carbonic anhydrase activity, and

  7. Highly stable linear carbonate-containing electrolytes with fluoroethylene carbonate for high-performance cathodes in sodium-ion batteries

    Science.gov (United States)

    Lee, Yongwon; Lee, Jaegi; Kim, Hyungsub; Kang, Kisuk; Choi, Nam-Soon

    2016-07-01

    Employing linear carbonates such as dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), and diethyl carbonate (DEC) as electrolyte solvents provides an opportunity to design appropriate electrolyte systems for high-performance sodium-ion batteries (SIBs). However, in practice, the use of linear carbonate-containing electrolytes is quite challenging because linear carbonates readily decompose at Na metal electrodes or sodiated anodes. One of the promising approaches is using an electrolyte additive to resolve the critical problems related to linear carbonates. Our investigation reveals that remarkable enhancement in electrochemical performance of Na4Fe3(PO4)2(P2O7) cathodes with linear carbonate-containing electrolytes is achieved by using a fluoroethylene carbonate (FEC) additive. Importantly, the initial Coulombic efficiency of the Na deposition/stripping on a stainless steel (SS) electrode is drastically improved from 16% to 90% by introducing the FEC additive into ethylene carbonate (EC)/propylene carbonate (PC)/DEC (5/3/2, v/v/v)/0.5 M NaClO4. The underlying mechanism of FEC at the electrode-electrolyte interface is clearly demonstrated by 13C nuclear magnetic resonance (NMR). In addition, the Na4Fe3(PO4)2(P2O7) cathode in EC/PC/DEC (5/3/2, v/v/v)/0.5 M sodium perchlorate (NaClO4) with FEC delivers a discharge capacity of 90.5 mAh g-1 at a current rate of C/2 and exhibits excellent capacity retention of 97.5% with high Coulombic efficiency of 99.6% after 300 cycles at 30 °C.

  8. Low-intensity resistance training after high-intensity resistance training can prevent the increase of central arterial stiffness.

    Science.gov (United States)

    Okamoto, T; Masuhara, M; Ikuta, K

    2013-05-01

    Although high-intensity resistance training increases arterial stiffness, low-intensity resistance training reduces arterial stiffness. The present study investigates the effect of low-intensity resistance training before and after high-intensity resistance training on arterial stiffness. 30 young healthy subjects were randomly assigned to a group that performed low-intensity resistance training before high-intensity resistance training (BLRT, n=10), a group that performed low-intensity resistance training after high-intensity resistance training (ALRT, n=10) and a sedentary control group (n=10). The BLRT and ALRT groups performed resistance training at 80% and 50% of one repetition maximum twice each week for 10 wk. Arterial stiffness was measured using carotid-femoral and femoral-ankle pulse wave velocity (PWV). One-repetition maximum strength in the both ALRT and BLRT significantly increased after the intervention (Ptraining in the ALRT group did not change from before training. In contrast, carotid-femoral PWV after combined training in the BLRT group increased from before training (P training in the both BLRT and ALRT groups did not change from before training. These results suggest that although arterial stiffness is increased by low-intensity resistance training before high-intensity resistance training, performing low-intensity resistance training thereafter can prevent the increase of arterial stiffness. © Georg Thieme Verlag KG Stuttgart · New York.

  9. EFFECT OF CARBON CONTENT ON MICROSTRUCTURE AND PROPERTIES OF HIGH STRENGTH AND HIGH ELONGATION STEELS

    Institute of Scientific and Technical Information of China (English)

    Y. Chen; X. Chen; P.H. Li; S.K. Pu; Z.X. Yuan; B.F. Xu; D.X. Lou; A.M. Guo; S.B.Zhou

    2003-01-01

    The microstructure and mechanical properties of new kind of hot-rolled high strengthand high elongation steels with retained austenite were studied by discussing the in-fluence of different carbon content. The research results indicate that carbon contenthas a significant effect on retaining austenite and consequently resulting in high elon-gation. Besides, new findings about relationship between carbon content and retainedaustenite as well as properties were discussed in the paper.

  10. EFFECT OF CARBON CONTENT ON MICROSTRUCTURE AND PROPERTIES OF HIGH STRENGTH AND HIGH ELONGATION STEELS

    Institute of Scientific and Technical Information of China (English)

    Y.Chen; X.Chen; 等

    2003-01-01

    The microstructure and mechanical properties of new kind of hot-rolled high strength and high elongation steels with retained austenite were studied by discussing the in-fluence of different carbon content.The research results indicate that carbon content has a significant effect on retaining austenite and consequently resulting in high elon-gation.Besides,new findings about relationship between carbon content and retained austenite as well as properties were discussed in the paper.

  11. Arterial Catheterization

    Science.gov (United States)

    ... way of keeping the blood pressure up. The arterial catheter allows accurate, second-to-second measurement of the blood pressure; repeated meas- urement is called monitoring. ■ High blood pressure (hypertension)— In some sit- uations, ...

  12. Microscopic Study of Carbon Surfaces Interacting with High Carbon Ferromanganese Slag

    Science.gov (United States)

    Safarian, Jafar; Kolbeinsen, Leiv

    2015-02-01

    The interaction of carbon materials with molten slags occurs in many pyro-metallurgical processes. In the production of high carbon ferromanganese in submerged arc furnace, the carbothermic reduction of MnO-containing silicate slags yields the metal product. In order to study the interaction of carbon with MnO-containing slags, sessile drop wettability technique is employed in this study to reduce MnO from a molten slag drop by carbon substrates. The interfacial area on the carbon substrate before and after reaction with slag is studied by scanning electron microscope. It is indicated that no Mn metal particles are found at the interface through the reduction of the MnO slag. Moreover, the reduction of MnO occurs through the contribution of Boudouard reaction and it causes carbon consumption in particular active sites at the interface, which generate carbon degradation and open pore growth at the interface. It is shown that the slag is fragmented to many micro-droplets at the reaction interface, potentially due to the effect on the interfacial energies of a provisional liquid Mn thin film. The rapid reduction of these slag micro-droplets affects the carbon surface with making deep micro-pores. A mechanism for the formation of slag micro-droplets is proposed, which is based on the formation of provisional micro thin films of liquid Mn at the interface.

  13. Peripheral arterial disease in a female using high-dose combined oral contraceptive pills

    Directory of Open Access Journals (Sweden)

    P Pallavee

    2013-01-01

    Full Text Available The association between oral contraceptive (OC pills and vascular diseases is well-known, although, the present generation of pills is considered to be relatively safer in this regard. Hormonal treatment for severe abnormal uterine bleeding is usually considered after ruling out malignancy, when such bleeding is resistant to all other forms of treatment. We report a case of severe peripheral arterial disease in a female, who had been on high-dose OC pills for an extended period of time for severe uterine bleeding.

  14. Peripheral arterial disease: A high risk – but neglected – disease population

    Directory of Open Access Journals (Sweden)

    Lip Gregory YH

    2005-06-01

    Full Text Available Abstract Peripheral arterial disease (PAD is a common, progressive manifestation of atherothrombotic vascular disease, which should be managed no different to cardiac disease. Indeed, there is growing evidence that PAD patients are a high risk group, although still relatively under-detected and under treated. This is despite the fact that PAD patients are an increased mortality rate comparable to those with pre-existing or established cardiovascular disease [myocardial infarction, stroke]. With a holistic approach to atherothrombotic vascular disease, our management of PAD can only get better.

  15. Ultra High Energy Density Cathodes with Carbon Nanotubes

    Science.gov (United States)

    2013-12-10

    34Enhanced Capacity and Rate Capability of Carbon Nanotube Based Anodes with Titanium Contacts for Lithium Ion Batteries," ACS Nano, vol. 4, pp. 6121- 6131...2010/10/26 2010. [2] S. L. Chou, et al., "Silicon/Single-Walled Carbon Nanotube Composite Paper as a Flexible Anode Material for Lithium Ion...AFRL-RV-PS- AFRL-RV-PS- TR-2013-0170 TR-2013-0170 ULTRA HIGH ENERGY DENSITY CATHODES WITH CARBON NANOTUBES Brian J. Landi, et al. Rochester

  16. Hybrid carbon nanostructure assemblage for high performance pseudo-capacitors

    Directory of Open Access Journals (Sweden)

    A. K. Mishra

    2012-06-01

    Full Text Available Investigation of novel nanocomposites for pseudo-capacitors with high capacitance and energy density is the spotlight of current energy research. In the present work, hybrid carbon nanostructure assemblage of graphene and multiwalled carbon nanotubes has been used as carbon support to nanostructured RuO2 and polyaniline for high energy supercapacitors. Maximum specific capacitances of 110, 235 and 440 F g−1 at the voltage sweep rate of 10 mV s−1 and maximum energy densities of 7, 12.5 and 20.5 Wh kg−1 were observed for carbon assemblage and its RuO2 and polyanilne decorated nanocomposites, respectively, with 1M H2SO4 as electrolyte.

  17. Facile synthesis of carbon nanofibers-bridged porous carbon nanosheets for high-performance supercapacitors

    Science.gov (United States)

    Jiang, Yuting; Yan, Jun; Wu, Xiaoliang; Shan, Dandan; Zhou, Qihang; Jiang, Lili; Yang, Deren; Fan, Zhuangjun

    2016-03-01

    A facile and one-step method is demonstrated to prepare carbon nanofibers (CNFs)-bridged porous carbon nanosheets (PCNs) through carbonization of the mixture of bacterial cellulose and potassium citrate. The CNFs bridge PCNs to form integrated porous carbon architecture with high specific surface area of 1037 m2 g-1, much higher than those of pure PCNs (381 m2 g-1) and CNFs (510 m2 g-1). As a consequence, the PCN/CNF composite displays high specific capacitance of 261 F g-1, excellent rate capability and outstanding cycling stability (97.6% of capacitance retention after 10000 cycles). Moreover, the assembled symmetric supercapacitor with PCN/CNF electrodes delivers an ultrahigh energy density of 20.4 Wh kg-1 and outstanding cycling life (94.8% capacitance retention after 10000 cycles) in an aqueous electrolyte.

  18. Asphalt-derived high surface area activated porous carbons for carbon dioxide capture.

    Science.gov (United States)

    Jalilov, Almaz S; Ruan, Gedeng; Hwang, Chih-Chau; Schipper, Desmond E; Tour, Josiah J; Li, Yilun; Fei, Huilong; Samuel, Errol L G; Tour, James M

    2015-01-21

    Research activity toward the development of new sorbents for carbon dioxide (CO2) capture have been increasing quickly. Despite the variety of existing materials with high surface areas and high CO2 uptake performances, the cost of the materials remains a dominant factor in slowing their industrial applications. Here we report preparation and CO2 uptake performance of microporous carbon materials synthesized from asphalt, a very inexpensive carbon source. Carbonization of asphalt with potassium hydroxide (KOH) at high temperatures (>600 °C) yields porous carbon materials (A-PC) with high surface areas of up to 2780 m(2) g(-1) and high CO2 uptake performance of 21 mmol g(-1) or 93 wt % at 30 bar and 25 °C. Furthermore, nitrogen doping and reduction with hydrogen yields active N-doped materials (A-NPC and A-rNPC) containing up to 9.3% nitrogen, making them nucleophilic porous carbons with further increase in the Brunauer-Emmett-Teller (BET) surface areas up to 2860 m(2) g(-1) for A-NPC and CO2 uptake to 26 mmol g(-1) or 114 wt % at 30 bar and 25 °C for A-rNPC. This is the highest reported CO2 uptake among the family of the activated porous carbonaceous materials. Thus, the porous carbon materials from asphalt have excellent properties for reversibly capturing CO2 at the well-head during the extraction of natural gas, a naturally occurring high pressure source of CO2. Through a pressure swing sorption process, when the asphalt-derived material is returned to 1 bar, the CO2 is released, thereby rendering a reversible capture medium that is highly efficient yet very inexpensive.

  19. Acute arterial thrombosis associated with inadvertent high dose of tranexamic acid

    Directory of Open Access Journals (Sweden)

    Surjya Prasad Upadhyay

    2013-01-01

    Full Text Available Tranexamic acid (TA act as anti-fibrinolytic agent and is widely used to limit bleeding in clinical practice. Tranexemic acid bind with plasminogen and prevent its conversion to plasmin, which limits the fibrinolytic pathway, so there is a theoretical risk of increasing thrombosis with high or prolonged therapy with TA. We encountered a case of acute arterial thrombosis following inadvertent administration of high dose of TA. A 27-years-old male with no other co-morbidity was ordered intravenous 1 gm TA to control excessive bleeding from previous bladder injury, but by mistake, he received 10 gm of TA. The patient developed signs and symptoms of acute ischemia in the right lower limb, which was diagnosed as acute iliac arterial thrombosis by computed tomography (CT angiography. The patient was managed with systemic heparinization, fasciotomy for impending gangrene and other supportive care following which he recovered fully within a few days. Caution should be exercised for all prophylactic use, especially with high dosage or prolonged therapy with TA.

  20. Cerebral blood volume and blood flow at varying arterial carbon dioxide tension levels in rabbits during propofol anesthesia.

    Science.gov (United States)

    Cenic, A; Craen, R A; Howard-Lech, V L; Lee, T Y; Gelb, A W

    2000-06-01

    There are little data on the effects of propofol on cerebral blood volume (CBV). We studied the effects of changes in PaCO(2) on CBV and cerebral blood flow (CBF) during propofol anesthesia in eight New Zealand white rabbits. We also investigated the effects of propofol over time on CBV and CBF during normocapnia (control group). At normocapnia, the mean (+/- SD) CBV and CBF values were 2.41 +/- 0.68 mL/100 g and 56 +/- 28 mL/100 g/min, respectively,. When PaCO(2) was reduced from 41 to 27 mm Hg, no significant change in either CBV or CBF was observed (P > 0.10). However, increasing PaCO(2) from 41 to 58 mm Hg resulted in a 30% increase in CBV (3.08 +/- 0.86 mL/100 g, P 0.10) during 2 h of propofol anesthesia. These results indicate that, during propofol anesthesia, cerebrovascular reactivity of blood flow and blood volume is maintained during hypercapnia but is markedly diminished during hypocapnia. During propofol anesthesia in rabbits with normal brains, a reduction in the arterial carbon dioxide level may not always be accompanied by a reduction in brain blood flow and blood volume.

  1. High Resolution Contrast-enhanced MRA in the Evaluation of Rabbit Carotid Artery

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    @@ Introduction:Accurate lumen definition of carotid artery is crucial for determining patient treatment, because a 70% or greater stenosis of a carotid artery will benefit from carotid endarterectomy to reduce the incidence of stroke[1].

  2. High Temperature Carbonized Grass as a High Performance Sodium Ion Battery Anode.

    Science.gov (United States)

    Zhang, Fang; Yao, Yonggang; Wan, Jiayu; Henderson, Doug; Zhang, Xiaogang; Hu, Liangbing

    2017-01-11

    Hard carbon is currently considered the most promising anode candidate for room temperature sodium ion batteries because of its relatively high capacity, low cost, and good scalability. In this work, switchgrass as a biomass example was carbonized under an ultrahigh temperature, 2050 °C, induced by Joule heating to create hard carbon anodes for sodium ion batteries. Switchgrass derived carbon materials intrinsically inherit its three-dimensional porous hierarchical architecture, with an average interlayer spacing of 0.376 nm. The larger interlayer spacing than that of graphite allows for the significant Na ion storage performance. Compared to the sample carbonized under 1000 °C, switchgrass derived carbon at 2050 °C induced an improved initial Coulombic efficiency. Additionally, excellent rate capability and superior cycling performance are demonstrated for the switchgrass derived carbon due to the unique high temperature treatment.

  3. Unusual High Oxygen Reduction Performance in All-Carbon Electrocatalysts

    Science.gov (United States)

    Wei, Wei; Tao, Ying; Lv, Wei; Su, Fang-Yuan; Ke, Lei; Li, Jia; Wang, Da-Wei; Li, Baohua; Kang, Feiyu; Yang, Quan-Hong

    2014-09-01

    Carbon-based electrocatalysts are more durable and cost-effective than noble materials for the oxygen reduction reaction (ORR), which is an important process in energy conversion technologies. Heteroatoms are considered responsible for the excellent ORR performance in many carbon-based electrocatalysts. But whether an all-carbon electrocatalyst can effectively reduce oxygen is unknown. We subtly engineered the interfaces between planar graphene sheets and curved carbon nanotubes (G-CNT) and gained a remarkable activity/selectivity for ORR (larger current, and n = 3.86, ~93% hydroxide + ~7% peroxide). This performance is close to that of Pt; and the durability is much better than Pt. We further demonstrate the application of this G-CNT hybrid as an all-carbon cathode catalyst for lithium oxygen batteries.We speculate that the high ORR activity of this G-CNT hybrid stems from the localized charge separation at the interface of the graphene and carbon nanotube, which results from the tunneling electron transfer due to the Fermi level mismatch on the planar and curved sp2 surfaces. Our result represents a conceptual breakthrough and pioneers the new avenues towards practical all-carbon electrocatalysis.

  4. Algunas consideraciones sobre la hipertensión arterial en la diabetes mellitus tipo 2 Some considerations related to arterial high blood pressure in Type 2 diabetes mellitus

    Directory of Open Access Journals (Sweden)

    Miguel Ángel Yanes Quesada

    2009-09-01

    Full Text Available Se realizó una revisión del tema relacionado con la hipertensión arterial en el paciente diabético tipo 2, con el objetivo de actualizar algunos elementos particulares en este grupo de pacientes. Se plantea que su prevalencia es considerablemente más alta que en la población no diabética, donde la hiperinsulinemia y la disfunción endotelial cobran un papel protagónico en su etiopatogenia. La hipertensión arterial en estos pacientes clínicamente se manifiesta como un patrón non dipper, lo que incrementa la morbimortalidad por esta entidad. El tratamiento medicamentoso es habitualmente necesario, y se usan como drogas de primera línea los inhibidores de la enzima convertidora, los antagonistas de los receptores de angiotensina ll y los calcioantagonistas, aunque se pueden utilizar también los diuréticos tiacídicos a dosis bajas.Authors made a review of the topic related to arterial high blood pressure in the patient presenting with Type 2 diabetes mellitus to update some particular elements in this group of patients. We propose that its prevalence is higher than that present in non-diabetic population, where the hyperinsulinism and the endothelial dysfunction have a leading role in its ethiopathogenesis. The arterial high blood pressure in these patients clinically is manifested as a non-dipper pattern increasing the morbidity and mortality. Drug therapy is commonly necessary and as first line-drugs are used the converting-enzyme inhibitors, the agiotensin-II receptors antagonists, and the antagonists-calcium, although the low-dose thiacidic diuretics.

  5. Carbon nanofibers grafted on activated carbon as an electrode in high-power supercapacitors.

    Science.gov (United States)

    Gryglewicz, Grażyna; Śliwak, Agata; Béguin, François

    2013-08-01

    A hybrid electrode material for high-power supercapacitors was fabricated by grafting carbon nanofibers (CNFs) onto the surface of powdered activated carbon (AC) through catalytic chemical vapor deposition (CCVD). A uniform thin layer of disentangled CNFs with a herringbone structure was deposited on the carbon surface through the decomposition of propane at 450 °C over an AC-supported nickel catalyst. CNF coating was controlled by the reaction time and the nickel content. The superior CNF/AC composite displays excellent electrochemical performance in a 0.5 mol L(-1) solution of K2 SO4 due to its unique structure. At a high scan rate (100 mV s(-1) ) and current loading (20 A g(-1) ), the capacitance values were three- and fourfold higher than those for classical AC/carbon black composites. Owing to this feature, a high energy of 10 Wh kg(-1) was obtained over a wide power range in neutral medium at a voltage of 0.8 V. The significant enhancement of charge propagation is attributed to the presence of herringbone CNFs, which facilitate the diffusion of ions in the electrode and play the role of electronic bridges between AC particles. An in situ coating of AC with short CNFs (below 200 nm) is a very attractive method for producing the next generation of carbon composite materials with a high power performance in supercapacitors working in neutral medium.

  6. Coronary angiography of pregnancy-associated coronary artery dissection: a high-risk procedure.

    Science.gov (United States)

    Martins, Raphaël Pedro; Leurent, Guillaume; Corbineau, Hervé; Fouquet, Olivier; Seconda, Sébastien; Baruteau, Alban E; Moreau, Olivier; Le Breton, Hervé; Bedossa, Marc

    2010-01-01

    Spontaneous coronary artery dissection (SCAD) is a rare cause of acute coronary syndrome occurring predominantly in young women without any cardiovascular risk factors, especially during the peripartum and early postpartum period. Here, we report a case of a 28-year-old pregnant woman who was found to have an isolated distal SCAD of the left anterior descending artery (LAD). Coronary angiography was complicated by extensive LAD and circumflex arteries dissection, requiring an emergency coronary artery bypass grafting associated with ventricular assist device implantation and underlying the extreme fragility of coronary arteries in pregnant women.

  7. Confinement of hydrogen at high pressure in carbon nanotubes

    Science.gov (United States)

    Lassila, David H.; Bonner, Brian P.

    2011-12-13

    A high pressure hydrogen confinement apparatus according to one embodiment includes carbon nanotubes capped at one or both ends thereof with a hydrogen-permeable membrane to enable the high pressure confinement of hydrogen and release of the hydrogen therethrough. A hydrogen confinement apparatus according to another embodiment includes an array of multi-walled carbon nanotubes each having first and second ends, the second ends being capped with palladium (Pd) to enable the high pressure confinement of hydrogen and release of the hydrogen therethrough as a function of palladium temperature, wherein the array of carbon nanotubes is capable of storing hydrogen gas at a pressure of at least 1 GPa for greater than 24 hours. Additional apparatuses and methods are also presented.

  8. Very high coronary artery calcium score with normal myocardial perfusion SPECT imaging is associated with a moderate incidence of severe coronary artery disease

    Energy Technology Data Exchange (ETDEWEB)

    Yuoness, Salem A.; Goha, Ahmed M.; Romsa, Jonathan G.; Akincioglu, Cigdem; Warrington, James C.; Datta, Sudip; Gambhir, Sanjay; Urbain, Jean-Luc C.; Vezina, William C. [London Health Sciences Centre, Department of Nuclear Medicine, London, ON (Canada); Massel, David R. [London Health Sciences Centre, Division of Cardiology, London, ON (Canada); Martell, Rafael [Private Practice, London, ON (Canada)

    2015-09-15

    Myocardial perfusion imaging (MPI) has limitations in the presence of balanced multivessel disease (MVD) and left main (LM) coronary artery disease, occasionally resulting in false-normal results despite the high cardiovascular risk associated with this condition. The purpose of this study was to assess the incidence of severe coronary artery disease (CAD) in the presence of a very high Agatston coronary artery calcium (CAC) score (>1,000) in stable symptomatic patients without known CAD but with normal MPI results. A total of 2,659 prospectively acquired consecutive patients were referred for MPI and evaluation of CAC score by CT. Of this patient population, 8 % (222/2,659) had ischemia without myocardial infarction (MI) on MPI and 11 % (298/2,659) had abnormal MPI (MI and/or ischemia). On presentation 1 % of the patients (26/2,659) were symptomatic, had a CAC score >1,000 and normal MPI results. The definition of normal MPI was strict and included a normal hemodynamic response without ischemic ECG changes and normal imaging, particularly absence of transient ischemic dilation. All of these 26 patients with a CAC score >1,000 and normal MPI findings underwent cardiac catheterization. Of these 26 patients, 58 % (15/26) had severe disease (≥70 % stenosis) leading to revascularization. Of this group, 47 % (7/15) underwent percutaneous intervention, and 53 % (8/15) underwent coronary artery bypass grafting. All of these 15 patients had either MVD (14/15) or LM coronary artery disease (1/15), and represented 0.6 % (15/2,659) of all referred patients (95 % CI 0.3 - 0.9 %). The majority, 90 % (8/9), had severe CAD with typical chest pain. A very high CAC score (>1,000) with normal MPI in a small subset of symptomatically stable patients was associated with a moderate incidence of severe CAD (95 % CI 37 - 77 %). Larger studies and/or a meta-analysis of small studies are needed to more precisely estimate the incidence of CAD in this population. This study also supports

  9. Risk of High Dietary Calcium for Arterial Calcification in Older Adults

    Directory of Open Access Journals (Sweden)

    Philip J. Klemmer

    2013-09-01

    Full Text Available Concern has recently arisen about the potential adverse effects of excessive calcium intakes, i.e., calcium loading from supplements, on arterial calcification and risks of cardiovascular diseases (CVD in older adults. Published reports that high calcium intakes in free-living adults have relatively little or no beneficial impact on bone mineral density (BMD and fracture rates suggest that current recommendations of calcium for adults may be set too high. Because even healthy kidneys have limited capability of eliminating excessive calcium in the diet, the likelihood of soft-tissue calcification may increase in older adults who take calcium supplements, particularly in those with age or disease-related reduction in renal function. The maintenance of BMD and bone health continues to be an important goal of adequate dietary calcium consumption, but eliminating potential risks of CVDs from excessive calcium intakes needs to be factored into policy recommendations for calcium by adults.

  10. Association between high-sensitive troponin I and coronary artery calcification in a Danish general population

    DEFF Research Database (Denmark)

    Olson, Fredrik; Engborg, Jonathan; Grønhøj, Mette H.;

    2016-01-01

    BACKGROUND: High-sensitive troponin I (hs-TnI) is an individual predictor of future cardiovascular disease (CVD). However, the relationship between hs-TnI and coronary artery calcification (CAC) as determined by computed tomography (CT) has not previously been investigated in a general population....... METHODS: 1173 randomized, middle-aged subjects without known CVD underwent a non-contrast cardiac-CT scan for CAC determination. Hs-TnI was detected using ARCHITECT STAT High Sensitive Troponin-I immunoassay. Total 10-year cardiovascular mortality risk was estimated using HeartScore. The relationship...... between hs-TnI and CAC was assessed using logistic regression analyses and receiver operating characteristic curves (ROC). RESULTS: Concentrations of hs-TnI above the limit of detection were measured in 89.3% of all subjects. Presence of CAC (Agatston score >0) was detected in 29% in the lowest hs...

  11. Improved Dispersion of Carbon Nanotubes in Polymers at High Concentrations

    Science.gov (United States)

    Liu, Chao-Xuan; Choi, Jin-Woo

    2012-01-01

    The polymer nanocomposite used in this work comprises elastomer poly(dimethylsiloxane) (PDMS) as a polymer matrix and multi-walled carbon nanotubes (MWCNTs) as a conductive nanofiller. To achieve uniform distribution of carbon nanotubes within the polymer, an optimized dispersion process was developed, featuring a strong organic solvent—chloroform, which dissolved PDMS base polymer easily and allowed high quality dispersion of MWCNTs. At concentrations as high as 9 wt.%, MWCNTs were dispersed uniformly through the polymer matrix, which presented a major improvement over prior techniques. The dispersion procedure was optimized via extended experimentation, which is discussed in detail. PMID:28348312

  12. A New High-Resolution Spectral Approach to Noninvasively Evaluate Wall Deformations in Arteries

    Directory of Open Access Journals (Sweden)

    Ivonne Bazan

    2014-01-01

    Full Text Available By locally measuring changes on arterial wall thickness as a function of pressure, the related Young modulus can be evaluated. This physical magnitude has shown to be an important predictive factor for cardiovascular diseases. For evaluating those changes, imaging segmentation or time correlations of ultrasonic echoes, coming from wall interfaces, are usually employed. In this paper, an alternative low-cost technique is proposed to locally evaluate variations on arterial walls, which are dynamically measured with an improved high-resolution calculation of power spectral densities in echo-traces of the wall interfaces, by using a parametric autoregressive processing. Certain wall deformations are finely detected by evaluating the echoes overtones peaks with power spectral estimations that implement Burg and Yule Walker algorithms. Results of this spectral approach are compared with a classical cross-correlation operator, in a tube phantom and “in vitro” carotid tissue. A circulating loop, mimicking heart periods and blood pressure changes, is employed to dynamically inspect each sample with a broadband ultrasonic probe, acquiring multiple A-Scans which are windowed to isolate echo-traces packets coming from distinct walls. Then the new technique and cross-correlation operator are applied to evaluate changing parietal deformations from the detection of displacements registered on the wall faces under periodic regime.

  13. A New High-Resolution Spectral Approach to Noninvasively Evaluate Wall Deformations in Arteries

    Science.gov (United States)

    Bazan, Ivonne; Negreira, Carlos; Ramos, Antonio; Brum, Javier; Ramirez, Alfredo

    2014-01-01

    By locally measuring changes on arterial wall thickness as a function of pressure, the related Young modulus can be evaluated. This physical magnitude has shown to be an important predictive factor for cardiovascular diseases. For evaluating those changes, imaging segmentation or time correlations of ultrasonic echoes, coming from wall interfaces, are usually employed. In this paper, an alternative low-cost technique is proposed to locally evaluate variations on arterial walls, which are dynamically measured with an improved high-resolution calculation of power spectral densities in echo-traces of the wall interfaces, by using a parametric autoregressive processing. Certain wall deformations are finely detected by evaluating the echoes overtones peaks with power spectral estimations that implement Burg and Yule Walker algorithms. Results of this spectral approach are compared with a classical cross-correlation operator, in a tube phantom and “in vitro” carotid tissue. A circulating loop, mimicking heart periods and blood pressure changes, is employed to dynamically inspect each sample with a broadband ultrasonic probe, acquiring multiple A-Scans which are windowed to isolate echo-traces packets coming from distinct walls. Then the new technique and cross-correlation operator are applied to evaluate changing parietal deformations from the detection of displacements registered on the wall faces under periodic regime. PMID:24688596

  14. Habitual rowing exercise is associated with high physical fitness without affecting arterial stiffness in older men.

    Science.gov (United States)

    Kawano, Hiroshi; Iemitsu, Motoyuki; Gando, Yuko; Ishijima, Toshimichi; Asaka, Meiko; Aoyama, Tomoko; Ando, Takafumi; Tokizawa, Ken; Miyachi, Motohiko; Sakamoto, Shizuo; Higuchi, Mitsuru

    2012-01-01

    The present study elucidated the effects of habitual rowing exercise on arterial stiffness and plasma levels of the vasoconstrictor endothelin-1 and the vasodilator nitric oxide (NO) in older men. Eleven rowers (68.0 ± 1.6 years) and 11 sedentary control older men (64.9 ± 1.1 years) were studied. Peak oxygen uptake (36.0 ± 1.7 vs. 27.7 ±1.9 ml · kg(-1) · min(-1)), leg press power (1346 ± 99 vs. 1077 ± 68 W), and HDL-cholesterol (75 ± 5 vs. 58 ±3 mg · ml(-1)) were higher and triglyceride (78 ± 9 vs. 120 ± 14 mg · ml(-1)) was lower in rowers than in control participants (all P cardio-ankle vascular index) and plasma endothelin-1 and NOx (nitrite + nitrate) levels did not differ between the two groups. These results suggest that habitual rowing exercise in older men is associated with high muscle power and aerobic capacity, and favourable blood lipid profile without affecting arterial stiffness or plasma levels of endotheline-1 and NO.

  15. High volume practice proved the safety of off-pump coronary artery bypass surgery in left main coronary artery lesions:a two-year single center experience

    Institute of Scientific and Technical Information of China (English)

    LIU Tong; LU Chun-shan; LU Jia-kai; GAN Hui-li; ZHANG Jian-qun; HUANG Fang-jong; GU Cheng-xiong; KONG Qing-yu; CAO Xiang-rong; BO Ping

    2012-01-01

    Background Left main coronary artery (LMCA) stenosis has been recognized as a risk factor for early death among patients undergoing coronary artery bypass grafting (CABG).This study aimed to assess if LMCA lesions pose an additional risk of early or mid-term mortality and/or a major adverse cardiac and cerebrovascular event (MACCE) after off-pump coronary artery bypass grafting (OPCABG),compared with non-left main coronary artery stenosis (non-mainstem disease).Methods From January 1,2009 to December 31,2010,4869 patients had a primary isolated OPCABG procedure at Beijing Anzhen Hospital.According to the pathology of LMCA lesions,they were retrospectively classified as a non-mainstem disease group (n=3933) or a LMCA group (n=936).Propensity scores were used to match the two groups,patients from the non-mainstem disease group (n=831) were also randomly selected to match patients from the LMCA group (n=831).Freedom from MACCE in the two groups was calculated using the Kaplan-Meier method.Results The difference in the mortality and the rate of MACCE during the first 30 days between the non-mainstem disease group and the LMCA group did not reach statistical significance (P=0.429,P=0.127 respectively).With a mean follow-up of (12.8±7.5) months and a cumulative follow-up of 1769.6 patient-years,the difference in the freedom from MACCEs between the two groups,calculated through Kaplan-Meier method,did not reach statistical significance (P=0.831).Conclusion Analysis of a high volume of OPCABG procedures proved that LMCA lesions do not pose additional early and mid-term risk to OPCABG.Therefore,a LMCA lesion is as safe as non-mainstem disease lesion during the OPCABG procedure.

  16. Calcium carbonate as a possible dosimeter for high irradiation doses

    Energy Technology Data Exchange (ETDEWEB)

    Negron M, A.; Ramos B, S.; Camargo R, C. [UNAM, Instituto de Ciencias Nucleares, Ciudad Universitaria, 04510 Mexico D. F. (Mexico); Uribe, R. M. [Kent State University, College of Technology, Kent OH (United States); Gomez V, V. [UNAM, Instituto de Quimica, Ciudad Universitaria, 04510 Mexico D. F. (Mexico); Kobayashi, K., E-mail: negron@nucleares.unam.mx [Yokohama National University (Japan)

    2014-08-15

    The aim of this work is to analyze the interactions of 5 MeV electron beam radiation and a 290 MeV/u Carbon beam with calcium carbonate (powder) at 298 K and at different irradiation doses, for the potential use of calcium carbonate as a high-dose dosimeter. The irradiation doses with the electron beam were from 0.015 to 9 MGy, and with Carbon beam from 1.5 kGy to 8 kGy. High-energy radiation induces the formation of free radicals in solid calcium carbonate that can be detected and measured by electron paramagnetic resonance (EPR). An increase of the EPR response for some of the free radicals produced in the sample was observed as a function of the irradiation dose. The response of one of the radicals decreased with the dose. These measurements are reproducible; the preparation of the sample is simple and inexpensive; and the signal is stable for several months. The response curves show that the dosimeter tends to saturate at 10 MGy. Based on these properties, we propose this chemical compound as a high-dose dosimeter, mainly for electron irradiation. (author)

  17. Highly porous activated carbons prepared from carbon rich Mongolian anthracite by direct NaOH activation

    Energy Technology Data Exchange (ETDEWEB)

    Byamba-Ochir, Narandalai [School of Chemical Engineering, Chonnam National University, 77 Yongbong-Ro, Gwangju 61186 (Korea, Republic of); Shim, Wang Geun [Department of Polymer Science and Engineering, Sunchon National University, 255 Jungang-Ro, Suncheon, Jeollanam-Do 57922 (Korea, Republic of); Balathanigaimani, M.S., E-mail: msbala@rgipt.ac.in [Department of Chemical Engineering, Rajiv Gandhi Institute of Petroleum Technology, Ratapur Chowk, Rae Bareli, 229316 Uttar Pradesh (India); Moon, Hee, E-mail: hmoon@jnu.ac.kr [School of Chemical Engineering, Chonnam National University, 77 Yongbong-Ro, Gwangju 61186 (Korea, Republic of)

    2016-08-30

    Highlights: • Highly porous carbon materials from Mongolian anthracite by chemical activation. • Cheaper and eco-friendly activation process has been employed. • Activated carbons with graphitic structure and energetically heterogeneous surface. • Surface hydrophobicity and porosity of the activated carbons can be controlled. - Abstract: Highly porous activated carbons (ACs) were prepared from Mongolian raw anthracite (MRA) using sodium hydroxide as an activation agent by varying the mass ratio (powdered MRA/NaOH) as well as the mixing method of chemical agent and powdered MRA. The specific BET surface area and total pore volume of the prepared MRA-based activated carbons (MACs) are in the range of 816–2063 m{sup 2}/g and of 0.55–1.61 cm{sup 3}/g, respectively. The pore size distribution of MACs show that most of the pores are in the range from large micropores to small mesopores and their distribution can be controlled by the mass ratio and mixing method of the activating agent. As expected from the intrinsic property of the MRA, the highly graphitic surface morphology of prepared carbons was confirmed from Raman spectra and transmission electron microscopy (TEM) studies. Furthermore the FTIR and XPS results reveal that the preparation of MACs with hydrophobic in nature is highly possible by controlling the mixing conditions of activating agent and powdered MRA. Based on all the results, it is suggested that the prepared MACs could be used for many specific applications, requiring high surface area, optimal pore size distribution, proper surface hydrophobicity as well as strong physical strength.

  18. Enhanced biological carbon consumption in a high CO2 ocean.

    Science.gov (United States)

    Riebesell, U; Schulz, K G; Bellerby, R G J; Botros, M; Fritsche, P; Meyerhöfer, M; Neill, C; Nondal, G; Oschlies, A; Wohlers, J; Zöllner, E

    2007-11-22

    The oceans have absorbed nearly half of the fossil-fuel carbon dioxide (CO2) emitted into the atmosphere since pre-industrial times, causing a measurable reduction in seawater pH and carbonate saturation. If CO2 emissions continue to rise at current rates, upper-ocean pH will decrease to levels lower than have existed for tens of millions of years and, critically, at a rate of change 100 times greater than at any time over this period. Recent studies have shown effects of ocean acidification on a variety of marine life forms, in particular calcifying organisms. Consequences at the community to ecosystem level, in contrast, are largely unknown. Here we show that dissolved inorganic carbon consumption of a natural plankton community maintained in mesocosm enclosures at initial CO2 partial pressures of 350, 700 and 1,050 microatm increases with rising CO2. The community consumed up to 39% more dissolved inorganic carbon at increased CO2 partial pressures compared to present levels, whereas nutrient uptake remained the same. The stoichiometry of carbon to nitrogen drawdown increased from 6.0 at low CO2 to 8.0 at high CO2, thus exceeding the Redfield carbon:nitrogen ratio of 6.6 in today's ocean. This excess carbon consumption was associated with higher loss of organic carbon from the upper layer of the stratified mesocosms. If applicable to the natural environment, the observed responses have implications for a variety of marine biological and biogeochemical processes, and underscore the importance of biologically driven feedbacks in the ocean to global change.

  19. Method for creating high carbon content products from biomass oil

    Science.gov (United States)

    Parker, Reginald; Seames, Wayne

    2012-12-18

    In a method for producing high carbon content products from biomass, a biomass oil is added to a cracking reactor vessel. The biomass oil is heated to a temperature ranging from about 100.degree. C. to about 800.degree. C. at a pressure ranging from about vacuum conditions to about 20,700 kPa for a time sufficient to crack the biomass oil. Tar is separated from the cracked biomass oil. The tar is heated to a temperature ranging from about 200.degree. C. to about 1500.degree. C. at a pressure ranging from about vacuum conditions to about 20,700 kPa for a time sufficient to reduce the tar to a high carbon content product containing at least about 50% carbon by weight.

  20. Preparation of spherical cobalt carbonate powder with high tap density

    Institute of Scientific and Technical Information of China (English)

    XIAO Jin; WANG Jian-feng; LIU Yong-dong; LI Jie; LIU Ye-xiang

    2006-01-01

    Spherical cobalt carbonate with high tap density, good crystallization and uniform particle size was prepared by controlled chemical crystal method using cobalt chloride and ammonium bicarbonate as cobalt source and precipitator. The effects of pH value and reaction time on crystallization and physical properties of cobalt carbonate were studied. The results show that the key factors influencing the preparation process of spherical cobalt carbonate with high tap density and good crystallization are how to control pH value (7.25 ± 0.05) and keep some reaction time (about 10 h). Co4O3 was prepared by sintering spherical morphology CoCO3 samples at varied temperatures. The results show that as the decomposition temperature increases, the as-obtained Co4O3 products with porous structure transform into polyhedral structure with glazed surface, and simultaneously the cobalt content and tap density increase. However, the specific surface area shows a trend of decrease.

  1. High capacitance of coarse-grained carbide derived carbon electrodes

    Science.gov (United States)

    Dyatkin, Boris; Gogotsi, Oleksiy; Malinovskiy, Bohdan; Zozulya, Yuliya; Simon, Patrice; Gogotsi, Yury

    2016-02-01

    We report exceptional electrochemical properties of supercapacitor electrodes composed of large, granular carbide-derived carbon (CDC) particles. Using a titanium carbide (TiC) precursor, we synthesized 70-250 μm sized particles with high surface area and a narrow pore size distribution. Electrochemical cycling of these coarse-grained powders defied conventional wisdom that a small particle size is strictly required for supercapacitor electrodes and allowed high charge storage densities, rapid transport, and good rate handling ability. The material showcased capacitance above 100 F g-1 at sweep rates as high as 250 mV s-1 in organic electrolyte. 250-1000 micron thick dense CDC films with up to 80 mg cm-2 loading showed superior areal capacitances. The material significantly outperformed its activated carbon counterpart in organic electrolytes and ionic liquids. Furthermore, large internal/external surface ratio of coarse-grained carbons allowed the resulting electrodes to maintain high electrochemical stability up to 3.1 V in ionic liquid electrolyte. In addition to presenting novel insights into the electrosorption process, these coarse-grained carbons offer a pathway to low-cost, high-performance implementation of supercapacitors in automotive and grid-storage applications.

  2. Associations between high factor VIII and low free protein S levels with traditional arterial thrombotic risk factors and their risk on arterial thrombosis : Results from a retrospective family cohort study

    NARCIS (Netherlands)

    Mulder, Rene; van Schouwenburg, Inge M.; Mahmoodi, Bakhtawar K.; Veeger, Nic J. G. M.; Mulder, Andre B.; Middeldorp, Saskia; Kluin-Nelemans, Hanneke C.; Lijfering, Willem M.

    2010-01-01

    Introduction: Whether high factor (F)VIII and low free protein S levels are risk factors for arterial thrombosis is unclarified. Material and Methods: In a post-hoc analysis of a single-centre retrospective family cohort, we determined if these two proteins could increase the risk of arterial

  3. COMPARISON OF HIGH-DEFINITION OSCILLOMETRIC AND DIRECT ARTERIAL BLOOD PRESSURE MEASUREMENT IN ANESTHETIZED CHEETAHS (ACINONYX JUBATUS).

    Science.gov (United States)

    Sant Cassia, Emma V; Boswood, Adrian; Tordiffe, Adrian S W

    2015-09-01

    Blood pressure measurement reveals important insights into the health of conscious and anesthetized individuals. This is of particular interest in cheetahs (Acinonyx jubatus), which in captivity are known to suffer from chronic diseases that may be associated with hypertension and which often require immobilization for transport or veterinary treatment. Invasive testing methods are considered the gold standard but are not practical in many settings. Consequently, it is important to evaluate the use of noninvasive methods in this species. Measurements for systolic, diastolic, and mean arterial pressure obtained using high-definition oscillometry (HDO) at the coccygeal artery were compared to simultaneous direct measurements obtained via catheterization of the femoral or dorsal pedal artery in eight anesthetized captive cheetahs during nine anesthetic events. Overall, HDO and direct measurements agreed most closely for mean arterial pressure, and the poorest agreement was observed for systolic pressure. There was a tendency for low diastolic pressures to be underestimated and for high diastolic pressures to be overestimated. Across all three parameters, HDO measurements from the tail overestimated directly measured pressures in the femoral artery and underestimated those in the dorsal pedal artery. HDO agreed most closely with directly measured dorsal pedal pressures. Mean arterial pressure showed the greatest precision (standard deviation of 10.2 mm Hg) and lowest bias (-1.2 mm Hg), with 75.9% of readings within 10 mm Hg of the direct dorsal pedal pressure. Agreement with systolic pressure was hindered by a high bias (-10.4 mm Hg), but if a correction factor of +10 mm Hg was applied to all systolic measurements, agreement was improved and 65.7% of readings were within 10 mm Hg of the direct pressure. When compared to criteria defined by the American College of Veterinary Internal Medicine for validation of blood pressure devices, results were favorable, but a

  4. Carbon dynamics in highly heterotrophic subarctic thaw ponds

    Directory of Open Access Journals (Sweden)

    T. Roiha

    2015-07-01

    Full Text Available Global warming has accelerated the formation of permafrost thaw ponds in several subarctic and arctic regions. These ponds are net heterotrophic as evidenced by their greenhouse gas (GHG supersaturation levels (CO2 and CH4, and generally receive large terrestrial carbon inputs from the thawing and eroding permafrost. We measured seasonal and vertical variations in the concentration and type of dissolved organic matter (DOM in five subarctic thaw (thermokarst ponds in northern Quebec, and explored how environmental gradients influenced heterotrophic and phototrophic biomass and productivity. Late winter DOM had low aromaticity indicating reduced inputs of terrestrial carbon, while the high concentration of dissolved organic carbon (DOC suggests that some production of non-chromophoric dissolved compounds by the microbial food web took place under the ice cover. Summer DOM had a strong terrestrial signature, but was also characterized with significant inputs of algal-derived carbon, especially at the pond surface. During late winter, bacterial production was low (maximum of 0.8 mg C m−3 d−1 and was largely based on free-living bacterioplankton (58 %. Bacterial production in summer was high (up to 58 mg C m−3 d−1, dominated by particle-attached bacteria (67 %, and strongly correlated to the amount of terrestrial carbon. Primary production was restricted to summer surface waters due to strong light limitation deeper in the water column or in winter. The phototrophic biomass was equal to the heterotrophic biomass, but as the algae were mostly composed of mixotrophic species, most probably they used bacteria rather than solar energy in such shaded ponds. According to the δ13C analyses, non-algal carbon supported 51 % of winter and 37 % of summer biomass of the phantom midge larvae, Chaoborus sp., that are at the top of the trophic chain. Our results point to a strong heterotrophic energy pathway in these thaw pond ecosystems, where

  5. Influence of Carbon Monoxide on Growth and Apoptosis of Human Umbilical Artery Smooth Muscle Cells and Vein Endothelial Cells

    Directory of Open Access Journals (Sweden)

    Yajuan Li, Hai Wang, Bin Yang, Jichen Yang, Xiuyan Ruan, Yadong Yang, Edward K. Wakeland, Quanzhen Li, Xiangdong Fang

    2012-01-01

    Full Text Available Carbon monoxide (CO is a vasoactive molecule that is generated by vascular cells as a byproduct of heme catabolism and it plays an important physiological role in circulation system. In order to investigate whether exogenous CO can mediate the growth and proliferation of vascular cells, in this study, we used 250 parts per million (ppm of CO to treat human umbilical artery smooth muscle cell (hUASMC and human umbilical vein endothelial cell (HuVEC and further evaluated the growth and apoptosis status of SMC and HuVEC. After SMC and HuVEC were exposed to CO for 7-day, the growth of SMC and HuVEC was significantly inhibited by CO in vitro on day 5 of CO exposure. And CO blocked cell cycle progress of SMC and HuVEC, more SMC and HuVEC stagnated at G0/G1 phase by flow cytometric analysis. Moreover, CO treatment inhibited SMC and HuVEC apoptosis caused by hydrogen peroxide through decreasing caspase 3 and 9 activities. To confirm the molecular mechanism of CO effect on SMC and HuVEC growth, we compared the gene expression profile in SMC and CO-treated SMC, HuVEC and CO-treated HuVEC. By microarray analysis, we found the expression level of some genes which are related to cell cycle regulation, cell growth and proliferation, and apoptosis were changed during CO exposure. We further identified that the down-regulated CDK2 contributed to arresting cell growth and the down-regulated Caspase 3 (CASP3 and Caspase 9 (CASP9 were associated with the inhibition of cell apoptosis. Therefore, CO exerts a certain growth arrest on SMC and HuVEC by inhibiting cell cycle transition from G0/G1 phase to S phase and has regulatory effect on cell apoptosis by regulating the expression of apoptosis-associated genes.

  6. Silicon-carbon interactions in high latitude watersheds

    Science.gov (United States)

    Humborg, C.; Morth, C.; Struyf, E.; Conley, D. J.

    2008-12-01

    Changes in climate and hydrology in high latitude regions could liberate large amounts of previously inactive organic carbon (OC) during a prolonging thawing period, and new studies have shown that a great deal of this organic C is remineralized as CO2 during its transport to the sea. However, OC (with its origin in atmospheric carbon) and dissolved silicate (DSi) concentrations in taiga and tundra rivers are intimately linked, and higher concentrations of weathering products are found in taiga and tundra rivers with a higher percentage of peat in their watersheds. It appears that the weathering regime of taiga and tundra watersheds is tightly linked to carbon-silicon interactions, in which carbon acts both as a weathering agent (soil CO2 from degradation of OC) and as a weathering product (DSi and bicarbonate). Whereas respiration of OC can be regarded as a positive feedback to global warming, weathering can be regarded as a negative feedback to global warming since atmospheric CO2 is converted to bicarbonate and thereby locked into the aquatic phase for geological time scales. Thus, bicarbonate export may compensate for significant amounts of exported OC thereby reducing the positive feedback to atmospheric CO2. However, the silicon-carbon interactions are not straight forward as suggested by classical inverse modelling,using the stochiometry of rock forming minerals as base, since high latitude wetlands contain a massive stock of amorphous silica (diatoms and phytoliths) buffering the actual DSi export, suggesting that the Si cycle is to a large extent biologically controlled.

  7. Intra-arterial papaverine and leg vascular resistance during in situ bypass surgery with high or low epidural anaesthesia

    DEFF Research Database (Denmark)

    Rørdam, Peter; Jensen, Leif Panduro; Schroeder, T V;

    1993-01-01

    patients were operated during high epidural anaesthesia (> Th. 10). Flow increased and arterial pressure decreased after i.a. papaverine in all patients. When compared with patients operated during high epidural anaesthesia, flow increase and decrease in vascular resistance took place in patients operated...

  8. The dynamic of aterosclerosis affection on brachio-cefalic arterys of the high risk patients under the hypolipidemic treatment

    Directory of Open Access Journals (Sweden)

    V.V. Simerzin

    2010-06-01

    Full Text Available Purpose. To study the statin influence on lipid exchange and the degree of the brachiocefalic arterys alteration. Methods. The research included 33 high risk patients. The patients inverstigation included lipid spectrum, blood coagulation indexes, by the means of triplex scanning of the brachiochefalic arterys the thickness of the intima - media complex and the expression of stenosis of carotid, vertebral and subclavian arterys were measured. Results. All the patients were divided into the groups according to the total cholesterol and low density lipoprotein cholesterol levels. Patients were divided into subgroups according to the expression of stenosis. The 1 group of patients received rosuvastating 10 mg, the 2 group - atorvastain 20 mg, 3the 3 group - simvastatin 40 mg. This inverstigation shows that the high risk patients with high levels of total cholesterol and low density lipoproteins have the highest expressiveness of brachiocefalic arterys atherosclerosis affection. Conclusion. The assignment of the statins to these patients is accompanied by the lowering of the levels of total cholesterol and low density lipoproteins and the quantity of arteries affected by the atherosclerosis and also by decreasing of the stenosis expression

  9. Oxidized LDL and Fructosamine Associated with Severity of Coronary Artery Atherosclerosis in Insulin Resistant Pigs Fed a High Fat/High NaCl Diet.

    Directory of Open Access Journals (Sweden)

    Timothy C Nichols

    Full Text Available Insulin-resistant subjects develop more severe and diffuse coronary artery atherosclerosis than insulin-sensitive controls but the mechanisms that mediate this atherosclerosis phenotype are unknown.To determine the metabolic parameters that associate with the severity of coronary atherosclerosis in insulin resistant pigs fed a high fat/high NaCl diet.The primary endpoint was severity of coronary atherosclerosis in adult pigs (Sus scrofa, n = 37 fed a high fat diet that also contained high NaCl (56% above recommended levels for 1 year.Twenty pigs developed severe and diffuse distal coronary artery atherosclerosis (i.e., severe = intimal area as a percent medial area > 200% in at least 2 coronary artery cross sections and diffuse distal = intimal area as a percent medial area ≥ 150% over 3 sections separated by 2 cm in the distal half of the coronary artery. The other 17 pigs had substantially less coronary artery atherosclerosis. All 37 pigs had blood pressure in a range that would be considered hypertensive in humans and developed elevations in total and LDL and HDL cholesterol, weight gain, increased backfat, and increased insulin resistance (Bergman Si without overt diabetes. Insulin resistance was not associated with atherosclerosis severity. Five additional pigs fed regular pig chow also developed increased insulin resistance but essentially no change in the other variables and little to no detectible coronary atherosclerosis. Most importantly, the 20 high fat/high NaCl diet-fed pigs with severe and diffuse distal coronary artery atherosclerosis had substantially greater increases (p< 0.05 in oxidized LDL (oxLDL and fructosamine consistent with increased protein glycation.In pigs fed a high fat/high NaCl diet, glycated proteins are induced in the absence of overt diabetes and this degree of increase is associated with the development of severe and diffuse distal coronary artery atherosclerosis.

  10. Oxidized LDL and Fructosamine Associated with Severity of Coronary Artery Atherosclerosis in Insulin Resistant Pigs Fed a High Fat/High NaCl Diet.

    Science.gov (United States)

    Nichols, Timothy C; Merricks, Elizabeth P; Bellinger, Dwight A; Raymer, Robin A; Yu, Jing; Lam, Diana; Koch, Gary G; Busby, Walker H; Clemmons, David R

    2015-01-01

    Insulin-resistant subjects develop more severe and diffuse coronary artery atherosclerosis than insulin-sensitive controls but the mechanisms that mediate this atherosclerosis phenotype are unknown. To determine the metabolic parameters that associate with the severity of coronary atherosclerosis in insulin resistant pigs fed a high fat/high NaCl diet. The primary endpoint was severity of coronary atherosclerosis in adult pigs (Sus scrofa, n = 37) fed a high fat diet that also contained high NaCl (56% above recommended levels) for 1 year. Twenty pigs developed severe and diffuse distal coronary artery atherosclerosis (i.e., severe = intimal area as a percent medial area > 200% in at least 2 coronary artery cross sections and diffuse distal = intimal area as a percent medial area ≥ 150% over 3 sections separated by 2 cm in the distal half of the coronary artery). The other 17 pigs had substantially less coronary artery atherosclerosis. All 37 pigs had blood pressure in a range that would be considered hypertensive in humans and developed elevations in total and LDL and HDL cholesterol, weight gain, increased backfat, and increased insulin resistance (Bergman Si) without overt diabetes. Insulin resistance was not associated with atherosclerosis severity. Five additional pigs fed regular pig chow also developed increased insulin resistance but essentially no change in the other variables and little to no detectible coronary atherosclerosis. Most importantly, the 20 high fat/high NaCl diet-fed pigs with severe and diffuse distal coronary artery atherosclerosis had substantially greater increases (p< 0.05) in oxidized LDL (oxLDL) and fructosamine consistent with increased protein glycation. In pigs fed a high fat/high NaCl diet, glycated proteins are induced in the absence of overt diabetes and this degree of increase is associated with the development of severe and diffuse distal coronary artery atherosclerosis.

  11. Effect of high laser output on the central bronchi and pulmonary artery.

    Science.gov (United States)

    Kirschbaum, A; Rexin, P; Bartsch, D K; Quint, K

    2017-05-01

    A diode-pump Nd:YAG high-power laser (wavelength 1320 nm, power 100 W) is routinely used to surgically remove lung metastases. Even pulmonary lesions in central locations are resectable via this method, yet it also carries a potential risk of damaging the larger bronchi and vessels in the vicinity. Studies investigating the safety of using high-power lasers are lacking. We therefore aimed to examine the direct effects of a 100-watt laser on the bronchi and pulmonary artery at a standard working velocity. From freshly slaughtered pigs, we isolated cylindrical specimens of the trachea, the main and lobar bronchi, and the central pulmonary artery from the both lungs. These specimens were fixed consecutively in rows behind each other on a Styrofoam surface in the laboratory. The laser's handle was clamped into a hydraulic feed unit so that the laser was focused at constant distance perpendicular to the tissue and would move at 10 mm/s over the specimens. The Nd:YAG Laser LIMAX® 120 functioned at a consistent power of 100 W during all the experiments. The lasered specimens were examined macroscopically and histologically for tissue damage. None of the trachea or bronchial walls were perforated. Compared to the pulmonary parenchyma, we observed no vaporization effects-only minor superficial coagulation (with a mean depth of 2.1 ± 0.8 mm). This finding was histologically confirmed in each specimen, which revealed mild superficial coagulation and no damage to the cartilage. In the presence of a residual peribronchial fatty tissue, the laser effect was even attenuated. The pulmonary arteries presented no lumen openings whatsoever, merely a discrete trace of coagulation. The vessel wall revealed increased vacuolization without alteration of the remaining vessel wall. In conclusion, laser resection at 100 W of the central lung areas is safe with respect to airways and blood vessels and the laser output does not need to be reduced when treating these areas.

  12. A new technology for production of high thickness carbon/carbon composites for launchers application

    Science.gov (United States)

    Albano, Marta; Delfini, Andrea; Pastore, Roberto; Micheli, Davide; Marchetti, Mario

    2016-11-01

    Carbon-Carbon (C/C) composites are known for their extraordinary stability and excellent mechanical properties, almost unchanged at high temperatures. Among the several advanced applications, C/C based materials can be used in engines as nozzle throat section for launchers. In particular, the main feature for such employment is the material high resistance in extreme thermal environment. On the other hand, large-size items are required for this kind of purposes, thus introducing criticalities in terms of material uniformity and final overall properties. Up to now, there no standard for the production of high thickness C/C structures. In this paper a novel manufacturing method is analyzed, following each phase of the process, from the carbon fiber preform design and preparation to the carbon densification by chemical vapor infiltration method. Five preforms of large dimensions with different characteristics have been manufactured and infiltrated. The realized prototypes have been then analyzed by means of mechanical, physical and morphological tests. Aim of the results of this preliminary work is to establish a set of guidelines for a well-defined high thickness C/C production method.

  13. High resolution MR angiography with rephasing and dephasing sequences for selective vascular imaging of arteries

    Energy Technology Data Exchange (ETDEWEB)

    Seiderer, M.; Laub, G.; Staebler, A.; Yousry, P.; Lauterjung, L.

    1988-03-01

    With rephasing and dephasing sequences the vascular system is imaged with high or low signal intensity whereas stationary tissue is imaged with identical signal intensity. With images recorded in systole and diastole followed by image subtraction separate imaging of arteries or veins without background superposition is possible. 13 patients with vascular lesions of the lower extremities and 7 volunteers were examined. Vascular stenosis, aneurysm, dilatation, occlusion and collateral vessels could be imaged similar to digital subtraction angiography. Vessels with a diameter down to 1 mm could be imaged. The large slice thickness up to 80 mm results in projection type images where the vascular tree is imaged over the whole field of view and without partial volume effects.

  14. Local motion-compensated method for high-quality 3D coronary artery reconstruction.

    Science.gov (United States)

    Liu, Bo; Bai, Xiangzhi; Zhou, Fugen

    2016-12-01

    The 3D reconstruction of coronary artery from X-ray angiograms rotationally acquired on C-arm has great clinical value. While cardiac-gated reconstruction has shown promising results, it suffers from the problem of residual motion. This work proposed a new local motion-compensated reconstruction method to handle this issue. An initial image was firstly reconstructed using a regularized iterative reconstruction method. Then a 3D/2D registration method was proposed to estimate the residual vessel motion. Finally, the residual motion was compensated in the final reconstruction using the extended iterative reconstruction method. Through quantitative evaluation, it was found that high-quality 3D reconstruction could be obtained and the result was comparable to state-of-the-art method.

  15. Study of the stenosis-inhibiting effects of high-dose rate endovascular irradiation in balloon injured rabbit iliac artery

    Energy Technology Data Exchange (ETDEWEB)

    Kobayashi, Masao; Sekine, Hiroshi; Suzuki, Akihiko; Ohyama, Noriaki; Hataba, Yoshiaki [Jikei Univ., Tokyo (Japan). School of Medicine

    2002-12-01

    With scanning electron microscopy, we investigated the effectiveness of inhibition by endovascular irradiation (Ir-192 high dose rate) of intimal hyperplasia after angioplasty. We also examined changes in the irradiated arterial vessel wall after balloon injury and the mechanism of the inhibition of intimal hyperplasia. Japanese white rabbits (male, 3.0-3.5 kg) were used. Under anesthesia, a percutaneous transluminal angioplasty balloon catheter was inserted into the iliac arteries and inflated to 6 atm for 1 minute 3 times at 1-minute intervals. One artery was irradiated (12 Gy) with an iridium-192 high-dose rate endovascular irradiation device (the reference point was set at 2 mm to center; dose rate 18-48 Gy/min). From 2 days to 12 weeks after the procedure, fixation was performed at a perfusion pressure of 120 to 150 cm H{sub 2}O, and the arteries were systematically examined. Endothelial cells after balloon injury with or without irradiation were examined with light microscopy or scanning electron microscopy. Endovascular irradiation inhibited intimal hyperplasia for at least 12 weeks. Irradiated arteries were not constricted, so we assumed that this phenomenon was caused by inhibition of negative remodeling. From 1 to 2 weeks after the procedure, we recognized mild intimal hyperplasia at nonirradiated arteries, but no hyperplasia recognized at irradiated arteries. This hyperplasia was mainly constituted by endothelial cells, and this change happened at least 2 days with scanning electron scopy. At the injury site, platelet aggregation, thrombus, and endothelial cells were observed. After irradiation, endothelial cells and nuclei were injured. Hypertrophic nuclei, the deformity of cell alignment, and stratified endothelial cells were recognized. It means that irradiation may affect the metabolism of the endothelial cells against normal formation with light microscopy. (author)

  16. Arterial Stiffness.

    Science.gov (United States)

    Avolio, Alberto

    2013-04-01

    Stiffness of large arteries has been long recognized as a significant determinant of pulse pressure. However, it is only in recent decades, with the accumulation of longitudinal data from large and varied epidemiological studies of morbidity and mortality associated with cardiovascular disease, that it has emerged as an independent predictor of cardiovascular risk. This has generated substantial interest in investigations related to intrinsic causative and associated factors responsible for the alteration of mechanical properties of the arterial wall, with the aim to uncover specific pathways that could be interrogated to prevent or reverse arterial stiffening. Much has been written on the haemodynamic relevance of arterial stiffness in terms of the quantification of pulsatile relationships of blood pressure and flow in conduit arteries. Indeed, much of this early work regarded blood vessels as passive elastic conduits, with the endothelial layer considered as an inactive lining of the lumen and as an interface to flowing blood. However, recent advances in molecular biology and increased technological sophistication for the detection of low concentrations of biochemical compounds have elucidated the highly important regulatory role of the endothelial cell affecting vascular function. These techniques have enabled research into the interaction of the underlying passive mechanical properties of the arterial wall with the active cellular and molecular processes that regulate the local environment of the load-bearing components. This review addresses these emerging concepts.

  17. Closure of digital arteries in high vascular tone states as demonstrated by measurement of systolic blood pressure in the fingers

    DEFF Research Database (Denmark)

    Krähenbühl, B; Nielsen, S L; Lassen, N A

    1977-01-01

    Finger systolic blood pressure (FSP) was measured indirectly in normal subjects and patients with primary Raynaud phenomenon by applying a thin-walled plastic cuff around the finger and a strain gauge more distally to detect volume changes. Inducing a high vascular tone in one or more fingers...... by direct cooling or intra-arterial noradrenaline infusion caused a marked drop in FSP in the exposed fingers, but not in the non-exposed fingers of the same hand. The fact that the non-exposed fingers retained the normal (arm systolic) pressure level is taken to indicate that palmar arch blood pressure...... also remained normal. In the high vascular tone state, a large transmural pressure difference must apparently be established before the digital arteries are forced open. The lowered opening pressure constitutes a manifestation of the closure phenomenon of the digital arteries described in patients...

  18. Closure of digital arteries in high vascular tone states as demonstrated by measurement of systolic blood pressure in the fingers

    DEFF Research Database (Denmark)

    Krähenbühl, B; Nielsen, S L; Lassen, N A

    1977-01-01

    Finger systolic blood pressure (FSP) was measured indirectly in normal subjects and patients with primary Raynaud phenomenon by applying a thin-walled plastic cuff around the finger and a strain gauge more distally to detect volume changes. Inducing a high vascular tone in one or more fingers...... by direct cooling or intra-arterial noradrenaline infusion caused a marked drop in FSP in the exposed fingers, but not in the non-exposed fingers of the same hand. The fact that the non-exposed fingers retained the normal (arm systolic) pressure level is taken to indicate that palmar arch blood pressure...... also remained normal. In the high vascular tone state, a large transmural pressure difference must apparently be established before the digital arteries are forced open. The lowered opening pressure constitutes a manifestation of the closure phenomenon of the digital arteries described in patients...

  19. High temperature SU-8 pyrolysis for fabrication of carbon electrodes

    DEFF Research Database (Denmark)

    Hassan, Yasmin Mohamed; Caviglia, Claudia; Hemanth, Suhith

    2017-01-01

    In this work, we present the investigation of the pyrolysis parameters at high temperature (1100 °C) for the fabrication of two-dimensional pyrolytic carbon electrodes. The electrodes were fabricated by pyrolysis of lithographically patterned negative epoxy based photoresist SU-8. A central...... composite experimental design was used to identify the influence of dwell time at the highest pyrolysis temperature and heating rate on electrical, electrochemical and structural properties of the pyrolytic carbon: Van der Pauw sheet resistance measurements, cyclic voltammetry, electrochemical impedance...... spectroscopy and Raman spectroscopy were used to characterize the pyrolytic carbon. The results show that the temperature increase from 900 °C to 1100 °C improves the electrical and electrochemical properties. At 1100 °C, longer dwell time leads to lower resistivity, while the variation of the pyrolysis...

  20. Sulfurized activated carbon for high energy density supercapacitors

    Science.gov (United States)

    Huang, Yunxia; Candelaria, Stephanie L.; Li, Yanwei; Li, Zhimin; Tian, Jianjun; Zhang, Lili; Cao, Guozhong

    2014-04-01

    Sulfurized activated carbon (SAC), made by coating the pore surface with thiophenic sulfur functional groups from the pyrolysis of sulfur flakes, were characterized and tested for supercapacitor applications. From X-ray photoelectron spectroscopy (XPS), the sulfur content in the SAC was found to be 2.7 at%. Electrochemical properties from potentiostatic and galvanostatic measurements, and electrochemical impedance spectroscopy (EIS) were used to evaluate the effect of sulfur on porous carbon electrodes. The SAC electrode exhibits better conductivity, and an obvious increase in specific capacitance that is almost 40% higher than plain activated carbons (ACs) electrode at a high current density of 1.4 A g-1. The proposed mechanism for improved conductivity and capacitive performance due to the sulfur functional groups on ACs will be discussed.

  1. Effect of cholesterol lowering on stiffness of aortic and femoral arterial walls in rabbits on a high fat diet

    Institute of Scientific and Technical Information of China (English)

    XUE Li; XU Wan-hai; XU Jin-zhi; ZHANG Tong; BI Hong-yuan; SHEN Bao-zhong

    2009-01-01

    Background Researches in arterial elasticity have increased over the past few years. We investigated the effects of simvastatin on vascular stiffness in fat fed rabbits by ultrasonography.Methods Thirty rabbits were assigned randomly to 3 groups: normal control group (A), the cholesterol group (B), simvastatin group (C: high fat diet for 4 weeks and high fat diet + simvastatin for further 4 weeks). Stiffness coefficient, pressure strain elastic modulus and velocity of pulse waves in abdominal aorta and femoral artery were measured by ultrasonographic echo tracking at the end of the 4th and the 8th weeks.Results At the end of the 4th week, stiffness coefficient, pressure strain elastic modulus and pulse wave velocity of femoral artery were significantly increased in group B compared with those in group A. Similarly, at the end of the 8th week, the same parameters of abdominal aorta were significantly increased in group B compared with those in group A. In contrast, stiffness coefficient, pressure strain elastic modulus and pulse wave velocity of femoral artery were significantly decreased in group C compared with those in group B, however, there was no significant difference in parameters of abdominal aorta between groups B and C.Conclusion Short term administration of simvastatin can improve the elasticity of femoral artery but not abdominal aorta.

  2. High dose of green tea infusion normalized spiral artery density in rats treated with the depot-medroxyprogesterone acetate.

    Science.gov (United States)

    Emilda, A S; Veri, Nora; Alchalidi, Alchalidi

    2017-01-01

    The purpose of this study was to investigate the effects of green tea (GT) on the spiral artery density and endometrial thickness in female rats treated with the depot-medroxyprogesterone acetate (DMPA). A total of 24 female rats were randomly divided into four groups (n = 6 each): The control group (no treatment), the DMPA-treated group, treated with DMPA and GT doses of 165 mg/kg of body weight/day, and treated with DMPA and GT doses of 330 mg/kg of body weight/day. Spiral artery density and endometrial thickness were subjected to histopathological analysis. Spiral artery density decreased in the DMPA-treated group, despite the insignificant difference (P > 0.05). With regard to the administration of GT at doses of 165 and 330 mg/g of body weight/day, only GT at the high dose was capable of significantly preventing a decrease in spiral artery density (P 0.05). Meanwhile, the administration of DMPA and/or DMPA with GT did not cause significant changes in endometrial thickness relative to the control group (P > 0.05). DMPA induced a decrease in spiral artery density, despite the insignificant differences, and these changes could be normalized by the administration of high doses of GT. Therefore, GT could be a candidate herb to prevent the adverse effects of the contraceptive DMPA.

  3. Sorbents for CO2 capture from high carbon fly ashes.

    Science.gov (United States)

    Maroto-Valer, M Mercedes; Lu, Zhe; Zhang, Yinzhi; Tang, Zhong

    2008-11-01

    Fly ashes with high-unburned-carbon content, referred to as fly ash carbons, are an increasing problem for the utility industry, since they cannot be marketed as a cement extender and, therefore, have to be disposed. Previous work has explored the potential development of amine-enriched fly ash carbons for CO2 capture. However, their performance was lower than that of commercially available sorbents, probably because the samples investigated were not activated prior to impregnation and, therefore, had a very low surface area. Accordingly, the work described here focuses on the development of activated fly ash derived sorbents for CO2 capture. The samples were steam activated at 850 degrees C, resulting in a significant increase of the surface area (1075 m2/g). The activated samples were impregnated with different amine compounds, and the resultant samples were tested for CO2 capture at different temperatures. The CO2 adsorption of the parent and activated samples is typical of a physical adsorption process. The impregnation process results in a decrease of the surface areas, indicating a blocking of the porosity. The highest adsorption capacity at 30 and 70 degrees C for the amine impregnated activated carbons was probably due to a combination of physical adsorption inherent from the parent sample and chemical adsorption of the loaded amine groups. The CO2 adsorption capacities for the activated amine impregnated samples are higher than those previously published for fly ash carbons without activation (68.6 vs. 45 mg CO2/g sorbent).

  4. Investigation of carriers of lustrous carbon at high temperatures

    Directory of Open Access Journals (Sweden)

    M. Holtzer

    2010-01-01

    Full Text Available Lustrous carbon is very important in processes of iron casting in green sand. Lustrous carbon (pirografit is a microcrystalline carbon form, which evolves from a gaseous phase. In the case of applying additions, generating lustrous carbon, for sands with bentonite, there is always a danger of emitting – due to a high temperature of liquid cast iron and a humidity -compounds hazardous for a human health. There can be: CO, SO2, benzene, toluene, ethylbenzene, xylene (the so-called: BTEX as well as polycyclic aromatic hydrocarbons (PAHs. In order to asses the selected mixtures: bentonite – carrier of lustrous carbon, in which a coal dust fraction was limited, the thermogravimetric analysis and the analysis of evolving gases were performed. Examinations were carried out in the Applications Laboratory NITZSCH-Gerätebau GmbH, Selb/Bavaria, Germany. The NETZSCH model STA 449 F3 Jupiter® simultaneous thermal analyzer was used to measure the mass change and transformation energetics of materials. The system employed for this work was equipped with an SiC furnace capable of operation from 25 to 1550°C. The mass spectrometer of the QMS 403 allows detection of mass numbers between 1 and 300 amu (atomic mass unit.

  5. A clinical model to identify patients with high-risk coronary artery disease.

    Science.gov (United States)

    Yang, Yelin; Chen, Li; Yam, Yeung; Achenbach, Stephan; Al-Mallah, Mouaz; Berman, Daniel S; Budoff, Matthew J; Cademartiri, Filippo; Callister, Tracy Q; Chang, Hyuk-Jae; Cheng, Victor Y; Chinnaiyan, Kavitha; Cury, Ricardo; Delago, Augustin; Dunning, Allison; Feuchtner, Gudrun; Hadamitzky, Martin; Hausleiter, Jörg; Karlsberg, Ronald P; Kaufmann, Philipp A; Kim, Yong-Jin; Leipsic, Jonathon; LaBounty, Troy; Lin, Fay; Maffei, Erica; Raff, Gilbert L; Shaw, Leslee J; Villines, Todd C; Min, James K; Chow, Benjamin J W

    2015-04-01

    This study sought to develop a clinical model that identifies patients with and without high-risk coronary artery disease (CAD). Although current clinical models help to estimate a patient's pre-test probability of obstructive CAD, they do not accurately identify those patients with and without high-risk coronary anatomy. Retrospective analysis of a prospectively collected multinational coronary computed tomographic angiography (CTA) cohort was conducted. High-risk anatomy was defined as left main diameter stenosis ≥50%, 3-vessel disease with diameter stenosis ≥70%, or 2-vessel disease involving the proximal left anterior descending artery. Using a cohort of 27,125, patients with a history of CAD, cardiac transplantation, and congenital heart disease were excluded. The model was derived from 24,251 consecutive patients in the derivation cohort and an additional 7,333 nonoverlapping patients in the validation cohort. The risk score consisted of 9 variables: age, sex, diabetes, hypertension, current smoking, hyperlipidemia, family history of CAD, history of peripheral vascular disease, and chest pain symptoms. Patients were divided into 3 risk categories: low (≤7 points), intermediate (8 to 17 points) and high (≥18 points). The model was statistically robust with area under the curve of 0.76 (95% confidence interval [CI]: 0.75 to 0.78) in the derivation cohort and 0.71 (95% CI: 0.69 to 0.74) in the validation cohort. Patients who scored ≤7 points had a low negative likelihood ratio (risk CAD was 1% in patients with ≤7 points and 16.7% in those with ≥18 points. We propose a scoring system, based on clinical variables, that can be used to identify patients at high and low pre-test probability of having high-risk CAD. Identification of these populations may detect those who may benefit from a trial of medical therapy and those who may benefit most from an invasive strategy. Copyright © 2015 American College of Cardiology Foundation. Published by

  6. Carbon dynamics in highly heterotrophic subarctic thaw ponds

    Science.gov (United States)

    Roiha, T.; Laurion, I.; Rautio, M.

    2015-12-01

    Global warming has accelerated the formation of permafrost thaw ponds in several subarctic and arctic regions. These ponds are net heterotrophic as evidenced by their greenhouse gas (GHG) supersaturation levels (CO2 and CH4), and generally receive large terrestrial carbon inputs from the thawing and eroding permafrost. We measured seasonal and vertical variations in the concentration and type of dissolved organic matter (DOM) in five subarctic thaw (thermokarst) ponds in northern Quebec, and explored how environmental gradients influenced heterotrophic and phototrophic biomass and productivity. Late winter DOM had low aromaticity indicating reduced inputs of terrestrial carbon, while the high concentration of dissolved organic carbon (DOC) suggests that some production of non-chromophoric dissolved compounds by the microbial food web took place under the ice cover. Summer DOM had a strong terrestrial signature, but was also characterized with significant inputs of algal-derived carbon, especially at the pond surface. During late winter, bacterial production was low (maximum of 0.8 mg C m-3 d-1) and was largely based on free-living bacterioplankton (58 %). Bacterial production in summer was high (up to 58 mg C m-3 d-1), dominated by particle-attached bacteria (67 %), and strongly correlated with the amount of terrestrial carbon. Primary production was restricted to summer surface waters due to strong light limitation deeper in the water column or in winter. The phototrophic biomass was equal to the heterotrophic biomass, but as the algae were mostly composed of mixotrophic species, most probably they used bacteria rather than solar energy in such shaded ponds. Our results point to a strong heterotrophic energy pathway in these thaw pond ecosystems, where bacterioplankton dominates the production of new carbon biomass in both summer and winter.

  7. Two- and three-dimensional quantitative image analysis of coronary arteries from high-resolution histological sections

    Science.gov (United States)

    Holmes, David R., III; Robb, Richard A.

    2000-05-01

    The study of coronary arteries has evolved from examining gross anatomy and morphology to scrutinizing micro-anatomy and cellular composition. Technological advances such as high-powered digital microscopes and high precision cutting devices have allowed clinicians to examine coronary artery morphology and pathology at micron resolution. Our work explores the composition of normal coronary arteries in order to provide the foundation for further study of remodeled tissue. The first of two coronary arteries was sliced into 442 sections with 4 micron inter-slice spacing. Each slice was stained for elastin and collagen. The second coronary artery was sectioned into 283 slices, also with 4 micron resolution. These slices were stained for cellular nuclei and smooth muscle. High sectioned into 283 slices, also with 4 micron resolution. These slices were stained for cellular nuclei and smooth muscle. High resolution light microscopy was used to image the sections. The data was analyzed for collagen/elastin content and nuclei density, respectively. Processing of this type of data is challenging in the areas of segmentation, visualization and quantification. Segmentation was confounded by variation in image quality as well as complexity of the coronary tissue. These problems were overcome by the development of 'smart' thresholding algorithms for segmentation. In addition, morphology and image statistics were used to further refine the result of the segmentation. Specificity/sensitivity analysis suggests that automatic segmentation can be very effective. 3D visualization of coronary arteries is challenging due to multiple tissue layers. Method such as summed voxel projection and maximum intensity projection appear to be effective. Shading methods also provide adequate visualization, however it is important to incorporate combined 2D and 3D displays. Surface rendering techniques are useful tools for visualizing parametric data. Quantification in 3D is simple in practice but

  8. High surface area silicon carbide-coated carbon aerogel

    Science.gov (United States)

    Worsley, Marcus A; Kuntz, Joshua D; Baumann, Theodore F; Satcher, Jr, Joe H

    2014-01-14

    A metal oxide-carbon composite includes a carbon aerogel with an oxide overcoat. The metal oxide-carbon composite is made by providing a carbon aerogel, immersing the carbon aerogel in a metal oxide sol under a vacuum, raising the carbon aerogel with the metal oxide sol to atmospheric pressure, curing the carbon aerogel with the metal oxide sol at room temperature, and drying the carbon aerogel with the metal oxide sol to produce the metal oxide-carbon composite. The step of providing a carbon aerogel can provide an activated carbon aerogel or provide a carbon aerogel with carbon nanotubes that make the carbon aerogel mechanically robust. Carbon aerogels can be coated with sol-gel silica and the silica can be converted to silicone carbide, improved the thermal stability of the carbon aerogel.

  9. High Conductivity Carbon-Carbon Heat Pipes for Light Weight Space Power System Radiators

    Science.gov (United States)

    Juhasz, Albert J.

    2008-01-01

    Based on prior successful fabrication and demonstration testing of a carbon-carbon heat pipe radiator element with integral fins this paper examines the hypothetical extension of the technology via substitution of high thermal conductivity composites which would permit increasing fin length while still maintaining high fin effectiveness. As a result the specific radiator mass could approach an ultimate asymptotic minimum value near 1.0 kg/m2, which is less than one fourth the value of present day satellite radiators. The implied mass savings would be even greater for high capacity space and planetary surface power systems, which may require radiator areas ranging from hundreds to thousands of square meters, depending on system power level.

  10. Selective and Regenerative Carbon Dioxide Capture by Highly Polarizing Porous Carbon Nitride.

    Science.gov (United States)

    Oh, Youngtak; Le, Viet-Duc; Maiti, Uday Narayan; Hwang, Jin Ok; Park, Woo Jin; Lim, Joonwon; Lee, Kyung Eun; Bae, Youn-Sang; Kim, Yong-Hyun; Kim, Sang Ouk

    2015-09-22

    Energy-efficient CO2 capture is a stringent demand for green and sustainable energy supply. Strong adsorption is desirable for high capacity and selective capture at ambient conditions but unfavorable for regeneration of adsorbents by a simple pressure control process. Here we present highly regenerative and selective CO2 capture by carbon nitride functionalized porous reduced graphene oxide aerogel surface. The resultant structure demonstrates large CO2 adsorption capacity at ambient conditions (0.43 mmol·g(-1)) and high CO2 selectivity against N2 yet retains regenerability to desorb 98% CO2 by simple pressure swing. First-principles thermodynamics calculations revealed that microporous edges of graphitic carbon nitride offer the optimal CO2 adsorption by induced dipole interaction and allows excellent CO2 selectivity as well as facile regenerability. This work identifies a customized route to reversible gas capture using metal-free, two-dimensional carbonaceous materials, which can be extended to other useful applications.

  11. A carbon-air battery for high power generation.

    Science.gov (United States)

    Yang, Binbin; Ran, Ran; Zhong, Yijun; Su, Chao; Tadé, Moses O; Shao, Zongping

    2015-03-16

    We report a carbon-air battery for power generation based on a solid-oxide fuel cell (SOFC) integrated with a ceramic CO2-permeable membrane. An anode-supported tubular SOFC functioned as a carbon fuel container as well as an electrochemical device for power generation, while a high-temperature CO2-permeable membrane composed of a CO3(2-) mixture and an O(2-) conducting phase (Sm(0.2)Ce(0.8)O(1.9)) was integrated for in situ separation of CO2 (electrochemical product) from the anode chamber, delivering high fuel-utilization efficiency. After modifying the carbon fuel with a reverse Boudouard reaction catalyst to promote the in situ gasification of carbon to CO, an attractive peak power density of 279.3 mW cm(-2) was achieved for the battery at 850 °C, and a small stack composed of two batteries can be operated continuously for 200 min. This work provides a novel type of electrochemical energy device that has a wide range of application potentials.

  12. Flexible Carbon Nanotube Films for High Performance Strain Sensors

    Directory of Open Access Journals (Sweden)

    Olfa Kanoun

    2014-06-01

    Full Text Available Compared with traditional conductive fillers, carbon nanotubes (CNTs have unique advantages, i.e., excellent mechanical properties, high electrical conductivity and thermal stability. Nanocomposites as piezoresistive films provide an interesting approach for the realization of large area strain sensors with high sensitivity and low manufacturing costs. A polymer-based nanocomposite with carbon nanomaterials as conductive filler can be deposited on a flexible substrate of choice and this leads to mechanically flexible layers. Such sensors allow the strain measurement for both integral measurement on a certain surface and local measurement at a certain position depending on the sensor geometry. Strain sensors based on carbon nanostructures can overcome several limitations of conventional strain sensors, e.g., sensitivity, adjustable measurement range and integral measurement on big surfaces. The novel technology allows realizing strain sensors which can be easily integrated even as buried layers in material systems. In this review paper, we discuss the dependence of strain sensitivity on different experimental parameters such as composition of the carbon nanomaterial/polymer layer, type of polymer, fabrication process and processing parameters. The insights about the relationship between film parameters and electromechanical properties can be used to improve the design and fabrication of CNT strain sensors.

  13. High pressure behavior of 3d transition metal carbonates

    Science.gov (United States)

    Farfan, G. A.; Wang, S.; Boulard, E.; Mao, W. L.

    2012-12-01

    Understanding the behavior of carbon-rich phases in Earth's lower mantle is critical for modeling the global carbon cycle since the lower mantle may be the major repository for carbon in our planet. We were interested in the behavior of carbonates containing 3d transition metals, which can exhibit unusual properties at extreme conditions. Thus, we studied siderite (FeCO3) and rhodochrosite (MnCO3) at high pressure using a diamond anvil cell coupled with Raman spectroscopy, X-ray diffraction (XRD) and X-ray emission spectroscopy. In siderite we observed a high to low spin transition and associated volume collapse at approximately 46 GPa which is consistent with previous reports. Our Raman data show that the C-O bonds soften when the Fe2+ volume collapses (Farfan et al, 2012). In contrast, our XES results indicate that the Mn2+ in rhodochrosite does not undergo a spin transition like siderite up to 50 GPa. We observed a new Raman peak emerging above 48 GPa, which is a similar pressure at which a new structure was found in a previous XRD study.

  14. On-Pump Beating Coronary Artery Bypass in High Risk Coronary Patients

    Directory of Open Access Journals (Sweden)

    Abbas Afrasiabirad

    2015-01-01

    Full Text Available Background: There are some conflicting results with Conventional Coronary Artery Bypass Grafts (CCABG with arrested heart in coronary high-risk patients. Moreover, performing off-pump CABG in these cases may be associated with serious complications. The objective of this study is to evaluate the efficacy of the on-pump beating CABG (OPBCABG in coronary high-risk patients in comparison with the conventional methods. Methods: In a prospective research study, 3000 off-pump CABG patients were considered during June 2003 to December 2011. Among these, 157 patients with one or more of the following risk factors were included for OPBCABG; severe left main stenosis, early post-acute myocardial infarction with ongoing chest pain, unstable angina, intractable ventricular arrhythmia, post complicated coronary intervention and severe left ventricular dysfunction. These patients were compared with 157 similar patients undergone CCABG with aortic cross clamp before 2003. Results: Preoperative patient characteristics revealed no significant differences between the two groups. The patients’ mean age and number of grafts were 57 years and 3 per patient respectively. Hospital mortality was 3.2% and 9% in OPBCABG and CCABG groups, respectively (P<0.001. Preoperative myocardial infarction, requirement of inotropic agents and intraaortic balloon pump, renal dysfunction and prolonged ventilation time were significantly higher in CCABG group. Conclusion: Our results suggest that OPBCABG is effective in coronary high-risk patients and significantly reduces mortality and the incidence of perioperative MI and other major complications.

  15. Allowable carbon emissions for medium-to-high mitigation scenarios

    Energy Technology Data Exchange (ETDEWEB)

    Tachiiri, Kaoru; Hargreaves, Julia C.; Annan, James D.; Kawamiya, Michio [Research Inst. for Global Change, Japan Agency for Marine-Earth Science and Technology, Yokohama, (Japan)], e-mail: tachiiri@jamstec.go.jp; Huntingford, Chris [Centre for Ecology and Hydrology, Wallingford (United Kingdom)

    2013-11-15

    Using an ensemble of simulations with an intermediate complexity climate model and in a probabilistic framework, we estimate future ranges of carbon dioxide (CO{sub 2}) emissions in order to follow three medium-high mitigation concentration pathways: RCP2.6, RCP4.5 and SCP4.5 to 2.6. Uncertainty is first estimated by allowing modelled equilibrium climate sensitivity, aerosol forcing and intrinsic physical and biogeochemical processes to vary within widely accepted ranges. Results are then constrained by comparison against contemporary measurements. For both constrained and unconstrained projections, our calculated allowable emissions are close to the standard (harmonised) emission scenarios associated with these pathways. For RCP4.5, which is the most moderate scenario considered in terms of required emission abatement, then after year 2100 very low net emissions are needed to maintain prescribed year 2100 CO{sub 2} concentrations. As expected, RCP2.6 and SCP4.5 to 2.6 require more strict emission reductions. The implication of this is that direct sequestration of carbon dioxide is likely to be required for RCP4.5 or higher mitigation scenarios, to offset any minimum emissions for society to function (the 'emissions floor'). Despite large uncertainties in the physical and biogeochemical processes, constraints from model-observational comparisons support a high degree of confidence in predicting the allowable emissions consistent with a particular concentration pathway. In contrast the uncertainty in the resulting temperature range remains large. For many parameter sets, and especially for RCP2.6, the land will turn into a carbon source within the twenty first century, but the ocean will remain as a carbon sink. For land carbon storage and our modelling framework, major reductions are seen in northern high latitudes and the Amazon basin even after atmospheric CO{sub 2} is stabilised, while for ocean carbon uptake, the tropical ocean regions will be a

  16. Electrocardiographically triggered CT angiography of the whole aorta and coronary arteries with high-pitch dual-source CT

    Institute of Scientific and Technical Information of China (English)

    张楠

    2013-01-01

    Objective To investigate the feasibility of comprehensive assessment of the whole aorta and coronary arteries(CA)simultaneously with high-pitch128-slice dualsource CT ECG-gated FLASH protocol.Methods A totalof 48 consecutive patients with suspected aortic diseases

  17. High coronary artery calcium score affects clinical outcome despite normal stress myocardial perfusion imaging and normal left ventricular ejection fraction

    DEFF Research Database (Denmark)

    Madsen, Claus Juul; Andersen, Kim F; Zerahn, Bo

    2013-01-01

    Normal myocardial perfusion imaging (MPI) indicates a low risk for cardiac death and new ischaemic events. However, the impact of normal MPI combined with a high coronary artery calcium score (CACS) is not clear. The aims of this study were to evaluate the risk of severely elevated CACS...

  18. Minimally invasive coronary artery bypass grafting versus percutaneous transluminal coronary angioplasty with stenting in isolated high-grade stenosis of the proximal left anterior descending coronary artery : Six months' angiographic and clinical follow-up of a prospective randomized study

    NARCIS (Netherlands)

    Drenth, DJ; Winter, JB; Veeger, NJGM; Monnink, SHJ; van Boven, AJ; Grandjean, JG; Mariani, MA; Boonstra, PW

    Objective: We sought to compare minimally invasive coronary artery bypass grafting (surgical intervention) with percutaneous transluminal coronary angioplasty with primary stenting (stenting) in patients having an isolated high-grade stenosis (American College of Cardiology/American Heart

  19. A simple and highly effective process for the preparation of activated carbons with high surface area

    Energy Technology Data Exchange (ETDEWEB)

    Li Ying, E-mail: liyingjlu@163.com [College of Chemistry, Jilin University, Changchun 130012 (China); Ding Xuefeng; Guo Yupeng; Wang Lili; Rong Chunguang; Qu Yuning; Ma Xiaoyu [College of Chemistry, Jilin University, Changchun 130012 (China); Wang Zichen, E-mail: wangzc@jlu.edu.cn [College of Chemistry, Jilin University, Changchun 130012 (China)

    2011-06-15

    Highlights: {yields} High surface area activated carbon can be prepared by rice husk H{sub 3}PO{sub 4} without pretreatment. {yields} The characteristics of the activated carbon were greatly influenced by post-processing method. {yields} The lower SiO{sub 2} content of the activated carbons, the higher pore volume the carbons had. {yields} Some silica in rice husk reacted with H{sub 3}PO{sub 4} to form SiP{sub 2}O{sub 7} which could be removed by post-process. - Abstract: Activated carbons with high surface area were prepared by phosphoric acid as activation agent and rice husks as precursors. It was found that the characteristics of the activated carbons were influenced not only by the preparation but also by the post-processing method. The high surface area of the activated carbons was prepared under the optimum condition (50% H{sub 3}PO{sub 4} with impregnation ratio of 5:1, activation temperature of 500 deg. C, activation time of 0.5 h, wash water temperature of 100 deg. C). SiO{sub 2} content could affect the surface area of activated carbons, either. The lower SiO{sub 2} content of the activated carbons, the higher pore volume the carbons had. The SiO{sub 2} content was 11.2% when used the optimum condition. The explanation was that silicon element in rice husks reacted with H{sub 3}PO{sub 4} to form silicon phosphate (SiP{sub 2}O{sub 7}), and it could be proved further by X-ray diffraction analysis, SiP{sub 2}O{sub 7} could be removed by post-process.

  20. Potassium vapor assisted preparation of highly graphitized hierarchical porous carbon for high rate performance supercapacitors

    Science.gov (United States)

    Liu, Zheng; Zeng, Ying; Tang, Qunli; Hu, Aiping; Xiao, Kuikui; Zhang, Shiying; Deng, Weina; Fan, Binbin; Zhu, Yanfei; Chen, Xiaohua

    2017-09-01

    Ultrahigh graphitized carbon microspheres with rich hierarchical pores (AGHPCM-1) have been successfully synthesized through the one-step activation-carbonization strategy (OACS) with porous sulfonated poly-divinylbenzene as the carbon precursor, iron as the hard template and catalyst, and potassium hydroxide (KOH) as activation agent. Through the XRD, TEM, Raman and BET analysis, AGHPCM-1 shows very high graphitization degree and rich micro-, meso- and macro-pores. More importantly, the mechanism for KOH to improve the graphitization degree of carbon materials in OACS has been illustrated by the thermodynamical theory. The tremendous heat releasing from the reaction between the catalyst precursor of Fe2O3 and potassium vapor plays a key role in the formation of graphitized carbon. It may provide a general direction to prepare highly graphitized porous carbon at a moderate temperature. Integrating the advantages of high graphitization degree and rich hierarchical porous structure, the AGHPCM-1 exhibits an excellent rate performance with a response to up to the high current density of 150 A g-1 and high scan rate of 2000 mV s-1. No obvious capacitance decay can be observed after 10000 charge/discharge cycles even at the high current density of 20 A g-1.

  1. High temperature carbon-carbon supercapacitor using ionic liquid as electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Balducci, A.; Dugas, R.; Taberna, P.L.; Simon, P. [Universite Paul Sabatier, CIRIMAT, UMR CNRS 5085, 118 Route de Narbonne, 31062 Toulouse Cedex (France); Plee, D. [ARKEMA, GRL, RN 117, 64170 Lacq (France); Mastragostino, M. [Universita di Bologna, Dipartimento di Scienza dei Metalli, Elettrochimica e Tecniche Chimiche, Sede Amministrativa, via San Donato 15, 40127 Bologna (Italy); Passerini, S. [ENEA (Italian National Agency for New Technologies, Energy and Environment), IDROCOMB, Casaccia Research Center, Via Anguillarese 301, 00060 Rome (Italy)

    2007-03-20

    This paper presents results about the electrochemical and cycling characterizations of a supercapacitor cell using a microporous activated carbon as the active material and N-butyl-N-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide (PYR{sub 14}TFSI) ionic liquid as the electrolyte. The microporous activated carbon exhibited a specific capacitance of 60 F g{sup -1} measured from the three-electrode cyclic voltammetry experiments at 20 mV s{sup -1} scan rate, with a maximum operating potential range of 4.5 V at 60 C. A coin cell assembled with this microporous activated carbon and PYR{sub 14}TFSI as the electrolyte was cycled for 40,000 cycles without any change of cell resistance (9 {omega} cm{sup 2}), at a voltage up to 3.5 V at 60 C, demonstrating a high cycling stability as well as a high stable specific capacitance in this ionic liquid electrolyte. These high performances make now this type of supercapacitor suitable for high temperature applications ({>=}60 C). (author)

  2. Highly porous activated carbons prepared from carbon rich Mongolian anthracite by direct NaOH activation

    Science.gov (United States)

    Byamba-Ochir, Narandalai; Shim, Wang Geun; Balathanigaimani, M. S.; Moon, Hee

    2016-08-01

    Highly porous activated carbons (ACs) were prepared from Mongolian raw anthracite (MRA) using sodium hydroxide as an activation agent by varying the mass ratio (powdered MRA/NaOH) as well as the mixing method of chemical agent and powdered MRA. The specific BET surface area and total pore volume of the prepared MRA-based activated carbons (MACs) are in the range of 816-2063 m2/g and of 0.55-1.61 cm3/g, respectively. The pore size distribution of MACs show that most of the pores are in the range from large micropores to small mesopores and their distribution can be controlled by the mass ratio and mixing method of the activating agent. As expected from the intrinsic property of the MRA, the highly graphitic surface morphology of prepared carbons was confirmed from Raman spectra and transmission electron microscopy (TEM) studies. Furthermore the FTIR and XPS results reveal that the preparation of MACs with hydrophobic in nature is highly possible by controlling the mixing conditions of activating agent and powdered MRA. Based on all the results, it is suggested that the prepared MACs could be used for many specific applications, requiring high surface area, optimal pore size distribution, proper surface hydrophobicity as well as strong physical strength.

  3. The development of high precision carbon fiber composite mirror

    Science.gov (United States)

    Xu, Liang; Ding, Jiao-teng; Wang, Yong-jie; Xie, Yong-jie; Ma, Zhen; Fan, Xue-wu

    2016-10-01

    Due to low density, high stiffness, low thermal expansion coefficient, duplicate molding, etc., carbon fiber reinforced polymer (CFRP) is one of the potential materials of the optical mirror. The process developed for Φ300mm high precision CFRP mirror described in this paper. A placement tool used to improve laying accuracy up to ± 0.1°.A special reinforced cell structure designed to increase rigidity and thermal stability. Optical replication process adopted for surface modification of the carbon fiber composite mirror blank. Finally, surface accuracy RMS of Φ300mm CFRP mirror is 0.22μm, surface roughness Ra is about 2nm, and the thermal stability can achieve 13nm /°C from the test result. The research content is of some reference value in the infrared as well as visible light applications.

  4. High-Efficient Excitation-Independent Blue Luminescent Carbon Dots

    Science.gov (United States)

    Liu, Hongzhen; Zhao, Xin; Wang, Fei; Wang, Yunpeng; Guo, Liang; Mei, Jingjing; Tian, Cancan; Yang, Xiaotian; Zhao, Dongxu

    2017-06-01

    Blue luminescent carbon dots (CDs) were synthesized by the hydrothermal method. Blue-shifts of the maximum emission wavelength from 480 to 443 nm were observed when the concentration of CD solution decreased. The photoluminescence (PL) spectra of CDs at low concentration showed an excitation-independent behaviour, which is very different from the previous reports. Two different emitting mechanisms might work: the intrinsic luminescence from sp2-carbon networks can be responsible for the shorter wavelength part of emission (excitation-independent) at low concentration and the high polarity of nanosized clusters led to the excitation-dependent behaviour of the longer wavelength part at high concentration of CD solution. The photophysical property and concentration-dependent behaviour of the CDs offered new insights into CDs from the viewpoints of both experiments and mechanisms, which will promote diverse potential applications of CDs in the near future.

  5. The giraffe kidney tolerates high arterial blood pressure by high renal interstitial pressure and low glomerular filtration rate.

    Science.gov (United States)

    Damkjaer, M; Wang, T; Brøndum, E; Østergaard, K H; Baandrup, U; Hørlyck, A; Hasenkam, J M; Smerup, M; Funder, J; Marcussen, N; Danielsen, C C; Bertelsen, M F; Grøndahl, C; Pedersen, M; Agger, P; Candy, G; Aalkjaer, C; Bie, P

    2015-08-01

    The tallest animal on earth, the giraffe (Giraffa camelopardalis) is endowed with a mean arterial blood pressure (MAP) twice that of other mammals. The kidneys reside at heart level and show no sign of hypertension-related damage. We hypothesized that a species-specific evolutionary adaption in the giraffe kidney allows normal for size renal haemodynamics and glomerular filtration rate (GFR) despite a MAP double that of other mammals. Fourteen anaesthetized giraffes were instrumented with vascular and bladder catheters to measure glomerular filtration rate (GFR) and effective renal plasma flow (ERPF). Renal interstitial hydrostatic pressure (RIHP) was assessed by inserting a needle into the medullary parenchyma. Doppler ultrasound measurements provided renal artery resistive index (RI). Hormone concentrations as well as biomechanical, structural and histological characteristics of vascular and renal tissues were determined. GFR averaged 342 ± 99 mL min(-1) and ERPF 1252 ± 305 mL min(-1) . RIHP varied between 45 and 140 mmHg. Renal pelvic pressure was 39 ± 2 mmHg and renal venous pressure 32 ± 4 mmHg. A valve-like structure at the junction of the renal and vena cava generated a pressure drop of 12 ± 2 mmHg. RI was 0.27. The renal capsule was durable with a calculated burst pressure of 600 mmHg. Plasma renin and AngII were 2.6 ± 0.5 mIU L(-1) and 9.1 ± 1.5 pg mL(-1) respectively. In giraffes, GFR, ERPF and RI appear much lower than expected based on body mass. A strong renal capsule supports a RIHP, which is >10-fold that of other mammals effectively reducing the net filtration pressure and protecting against the high MAP. © 2015 Scandinavian Physiological Society. Published by John Wiley & Sons Ltd.

  6. Collapse of accreting carbon-oxygen white dwarfs induced by carbon deflagration at high density

    Energy Technology Data Exchange (ETDEWEB)

    Nomoto, K.

    1986-01-01

    A critical condition is obtained for which carbon deflagration induces collapse of an accreting C + O white dwarf, not explosion. If the carbon deflagration is initiated at central density as high as 10/sup 10/ g cm/sup -3/ and if the propagation of the deflagration wave is slower than approx. 0.15 upsilon/sub s/ (upsilon/sub s/ is the sound speed), electron capture behind the burning front induces collapse to form a neutron star. This is the case for both conductive and convective deflagrations. Such a high central density can be reached if the white dwarf is sufficiently massive and cold at the onset of accretion and if the accretion rate is in the appropriate range. Models for Type Ia and Ib supernovae are also discussed. 66 refs., 8 figs.

  7. Nanoporous Carbon Nitride: A High Efficient Filter for Seawater Desalination

    OpenAIRE

    Weifeng LI; Yang, Yanmei; Zhou, Hongcai; Zhang, Xiaoming; Zhao, Mingwen

    2015-01-01

    The low efficiency of commercially-used reverse osmosis (RO) membranes has been the main obstacle in seawater desalination application. Here, we report the auspicious performance, through molecular dynamics simulations, of a seawater desalination filter based on the recently-synthesized graphene-like carbon nitride (g-C2N) [Nat. Commun., 2015, 6, 6486]. Taking advantage of the inherent nanopores and excellent mechanical properties of g-C2N filter, highly efficient seawater desalination can be...

  8. Highly fluorescent xerogels with entrapped carbon dots for organic scintillators

    Energy Technology Data Exchange (ETDEWEB)

    Quaranta, A., E-mail: quaranta@ing.unitn.it [University of Trento, Department of Industrial Engineering, via Mesiano, 77, 38123 Trento (Italy); Laboratori Nazionali di Legnaro, INFN, Viale dell' Università, 2, 35020 Legnaro (PD) (Italy); Carturan, S. [Laboratori Nazionali di Legnaro, INFN, Viale dell' Università, 2, 35020 Legnaro (PD) (Italy); University of Padova, Department of Physics and Astronomy “Galileo Galilei”, Via Marzolo, 8, 35131 Padova (Italy); Campagnaro, A.; Dalla Palma, M. [University of Trento, Department of Industrial Engineering, via Mesiano, 77, 38123 Trento (Italy); Laboratori Nazionali di Legnaro, INFN, Viale dell' Università, 2, 35020 Legnaro (PD) (Italy); Giarola, M.; Daldosso, N. [University of Verona, Department of Informatics, Strada le Grazie,15, 37134 Verona (Italy); Maggioni, G. [Laboratori Nazionali di Legnaro, INFN, Viale dell' Università, 2, 35020 Legnaro (PD) (Italy); University of Padova, Department of Physics and Astronomy “Galileo Galilei”, Via Marzolo, 8, 35131 Padova (Italy); Mariotto, G. [University of Verona, Department of Informatics, Strada le Grazie,15, 37134 Verona (Italy)

    2014-02-28

    Organically modified silicate thin film and bulk samples were prepared using [3-(2-aminoethylamino)propyl]trimethoxysilane (AEAP-TMOS) as precursor with the addition of different amounts of AEAP-TMOS functionalized C-dots, prepared by reaction of AEAP-TMOS and citric acid at high temperature. The synthesis of surface functionalized C-dots was followed by Fourier Transform Infrared (FTIR) spectroscopy, and the C-dots optical properties were characterized by optical absorption and UV–vis fluorescence. Thin xerogel films and bulk samples were studied by FTIR, Raman and fluorescence spectroscopy. Intense blue-green emission was observed by UV excitation of functionalized C-dots. Carbon quantum dot (CQD) luminescence was preserved also in the xerogel matrices, and the energy transfer from the matrix to CQDs, which is a key characteristic for scintillation detectors, was investigated in the two systems. - Highlights: • Functionalized carbon dots were synthesized. • Carbon dots were dispersed in hybrid xerogel bulk and thin film. • Carbon dots exhibit a strong tunable blue luminescence. • Xerogels were characterized by FT-IR, Raman and fluorescence spectroscopies. • Energy transfer processes were evidenced between C-dots and xerogel matrix.

  9. Efficacy of Prophylactic Uterine Artery Embolization before Obstetrical Procedures with High Risk for Massive Bleeding

    Science.gov (United States)

    Ko, Heung Kyu; Ko, Gi Young; Gwon, Dong Il; Kim, Jin Hyung; Han, Kichang; Lee, Shin-Wha

    2017-01-01

    Objective To evaluate the safety and efficacy of prophylactic uterine artery embolization (UAE) before obstetrical procedures with high risk for massive bleeding. Materials and Methods A retrospective review of 29 female patients who underwent prophylactic UAE from June 2009 to February 2014 was performed. Indications for prophylactic UAE were as follows: dilatation and curettage (D&C) associated with ectopic pregnancy (cesarean scar pregnancy, n = 9; cervical pregnancy, n = 6), termination of pregnancy with abnormal placentation (placenta previa, n = 8), D&C for retained placenta with vascularity (n = 5), and D&C for suspected gestational trophoblastic disease (n = 1). Their medical records were reviewed to evaluate the safety and efficacy of UAE. Results All women received successful bilateral prophylactic UAE followed by D&C with preservation of the uterus. In all patients, UAE followed by obstetrical procedure prevented significant vaginal bleeding on gynecologic examination. There was no major complication related to UAE. Vaginal spotting continued for 3 months in three cases. Although oligomenorrhea continued for six months in one patient, normal menstruation resumed in all patients afterwards. During follow-up, four had subsequent successful natural pregnancies. Spontaneous abortion occurred in one of them during the first trimester. Conclusion Prophylactic UAE before an obstetrical procedure in patients with high risk of bleeding or symptomatic bleeding may be a safe and effective way to manage or prevent serious bleeding, especially for women who wish to preserve their fertility. PMID:28246515

  10. Transcatheter arterial chemo-lipiodol infusion for unresectable hepatocellular carcinoma in 96 high-risk patients

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, H.-J. [Department of Radiology and Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul (Korea, Republic of); Kim, J.H., E-mail: m1fenew@daum.ne [Department of Radiology and Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul (Korea, Republic of); Kim, K.-A.; Lee, I.-S.; Ko, G.-Y.; Song, H.-Y.; Gwon, D.I. [Department of Radiology and Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul (Korea, Republic of)

    2010-04-15

    Aim: To evaluate the safety and efficacy of transcatheter arterial chemo-lipiodol infusion (TACL) in high-risk patients with unresectable hepatocellular carcinoma (HCC). Materials and methods: From January 2005 to April 2009, 96 patients underwent TACL. All patients had diffuse, infiltrative or multifocal tumours. Twenty-nine (30%) patients had an increased serum bilirubin level (>=2 mg/dl), and 75 patients (78%) had a low serum albumin level (<3.5 mg/dl). The Child-Pugh (CP) score was 9 or more in 13 (14%) patients. Sixty-five patients (68%) had major portal vein occlusion. Sixteen patients (17%) had biliary dilatation. Results: TACL was technically successful in all patients. After TACL, 18 (19%) of the 96 patients showed tumour response using computed tomography (CT) criteria. The 30 day mortality and morbidity rates were 1 and 2%, respectively. The median survival period was 8.6 months, and the overall 6 month, 1, 2, and 3 year survival rates were 59, 44, 26, and 15%, respectively. Portal vein occlusion (p < 0.001) was the only significant risk factor associated with the length of the survival period after TACL, whereas the CP score (p = 0.498), serum bilirubin level (p = 0.153), serum albumin level (p = 0.399), and biliary obstruction (p = 0.636) had no significant effect. Conclusions: TACL can be performed safely in high risk HCC patients resulting in a median survival rate of 8.6 months in the present series.

  11. [High-sensitivity troponin in patients with stable coronary artery disease].

    Science.gov (United States)

    van 't Hof, Arnoud W J

    2015-01-01

    With the introduction of more sensitive markers of myocardial necrosis, it was shown that the diagnosis of (acute) myocardial infarction could be improved. However, many patients without myocardial infarction have elevated troponin levels (low sensitivity), resulting in additional diagnostic testing and longer admission times to find the cause of the troponin rise. Elevated troponin levels in these patients were found to have limited diagnostic but strong prognostic value. This led to studies assessing the value of high-sensitivity troponin in patients with stable disease, e.g. coronary artery disease, or even in patients without apparent (clinical) disease. These studies consistently showed a strong association with long-term (cardiac) mortality. What is the value for the general physician in daily practice? Although troponin levels may help in finding (healthy?) patients at higher risk, it remains unclear whether interventions (medication, lifestyle) are more (cost-)effective in this high-risk subgroup. The role of troponin levels as a prognostic marker in stable patients therefore remains to be determined.

  12. Efficacy of prophylactic uterine artery embolization before obstetrical procedures with high risk for massive bleeding

    Energy Technology Data Exchange (ETDEWEB)

    Ko, Heung Kyu; Shin, Ji Hoon; Ko, Gi Young; Gwon, Dong Il; Kim, Jin Hyung; Han, Ki Chang; Lee, Shin Wha [Asan Medical Center, Ulsan University College of Medicine, Seoul (Korea, Republic of)

    2017-04-15

    To evaluate the safety and efficacy of prophylactic uterine artery embolization (UAE) before obstetrical procedures with high risk for massive bleeding. A retrospective review of 29 female patients who underwent prophylactic UAE from June 2009 to February 2014 was performed. Indications for prophylactic UAE were as follows: dilatation and curettage (D and C) associated with ectopic pregnancy (cesarean scar pregnancy, n = 9; cervical pregnancy, n = 6), termination of pregnancy with abnormal placentation (placenta previa, n = 8), D and C for retained placenta with vascularity (n = 5), and D and C for suspected gestational trophoblastic disease (n = 1). Their medical records were reviewed to evaluate the safety and efficacy of UAE. All women received successful bilateral prophylactic UAE followed by D and C with preservation of the uterus. In all patients, UAE followed by obstetrical procedure prevented significant vaginal bleeding on gynecologic examination. There was no major complication related to UAE. Vaginal spotting continued for 3 months in three cases. Although oligomenorrhea continued for six months in one patient, normal menstruation resumed in all patients afterwards. During follow-up, four had subsequent successful natural pregnancies. Spontaneous abortion occurred in one of them during the first trimester. Prophylactic UAE before an obstetrical procedure in patients with high risk of bleeding or symptomatic bleeding may be a safe and effective way to manage or prevent serious bleeding, especially for women who wish to preserve their fertility.

  13. High-quality 3-D coronary artery imaging on an interventional C-arm x-ray system

    Energy Technology Data Exchange (ETDEWEB)

    Hansis, Eberhard; Carroll, John D.; Schaefer, Dirk; Doessel, Olaf; Grass, Michael [Philips Technologie GmbH Forschungslaboratorien, Roentgenstrasse 24-26, 22335 Hamburg (Germany); Department of Medicine, Division of Cardiology, Health Sciences Center, University of Colorado, Denver, Colorado 80262 (United States); Philips Technologie GmbH Forschungslaboratorien, Roentgenstrasse 24-26, 22335 Hamburg (Germany); Institute of Biomedical Engineering, University of Karlsruhe, Kaiserstr. 12, 76131 Karlsruhe (Germany); Philips Technologie GmbH Forschungslaboratorien, Roentgenstrasse 24-26, 22335 Hamburg (Germany)

    2010-04-15

    Purpose: Three-dimensional (3-D) reconstruction of the coronary arteries during a cardiac catheter-based intervention can be performed from a C-arm based rotational x-ray angiography sequence. It can support the diagnosis of coronary artery disease, treatment planning, and intervention guidance. 3-D reconstruction also enables quantitative vessel analysis, including vessel dynamics from a time-series of reconstructions. Methods: The strong angular undersampling and motion effects present in gated cardiac reconstruction necessitate the development of special reconstruction methods. This contribution presents a fully automatic method for creating high-quality coronary artery reconstructions. It employs a sparseness-prior based iterative reconstruction technique in combination with projection-based motion compensation. Results: The method is tested on a dynamic software phantom, assessing reconstruction accuracy with respect to vessel radii and attenuation coefficients. Reconstructions from clinical cases are presented, displaying high contrast, sharpness, and level of detail. Conclusions: The presented method enables high-quality 3-D coronary artery imaging on an interventional C-arm system.

  14. Intracranial arterial calcification is highly prevalent in hemodialysis patients but does not associate with acute ischemic stroke.

    Science.gov (United States)

    Power, Albert; Chan, Kakit; Haydar, Ali; Hamady, Mohamed; Cairns, Tom; Taube, David; Duncan, Neill

    2011-04-01

    Intracranial arterial calcification (IAC) is associated with ischemic stroke in the general population but this relationship has not been examined in hemodialysis patients. We examined the factors associated with IAC and its relationship with acute ischemic stroke in this population. We retrospectively studied 490 head computed tomographic scans from 2225 hemodialysis patients presenting with neurological symptoms at our center (October 2005-May 2009). Intracranial arterial calcification was graded using a validated scoring system. Multivariate regression was used to examine the factors associated with the presence of IAC, its severity, and its ability to predict acute ischemic stroke. Weibull's survival models analyzed the relationship between IAC severity and survival. Ninety-five percent of patients with ischemic stroke had IAC vs. 83% in the nonstroke group (P=0.02). Intracranial arterial calcification severity increased with age (Pacute ischemic stroke (P=0.05) on logistic regression analysis. High-grade and not low-grade IAC was associated with worse survival (P=0.008). Intracranial arterial calcification is highly prevalent in hemodialysis patients, especially in those with acute ischemic stroke. Its severity is prognostically significant and associated with risk factors for vascular calcification and may confer a greater risk of acute ischemic stroke. The mechanisms underlying the high incidence of ischemic stroke in this patient group require further comprehensive study. © 2011 The Authors. Hemodialysis International © 2011 International Society for Hemodialysis.

  15. "Medical high risk" designation is not associated with survival after carotid artery stenting.

    Science.gov (United States)

    Yuo, Theodore H; Goodney, Philip P; Powell, Richard J; Cronenwett, Jack L

    2008-02-01

    While medical high risk (MHR) has been proposed as an indication for carotid artery stenting (CAS), the impact of MHR on long-term survival and stroke after CAS has not been described. A retrospective chart review of CAS procedures at our institution was performed. One hundred seventy-nine consecutive patients who underwent 196 CAS procedures were classified by MHR status based on cardiac, pulmonary, and renal criteria routinely used in high-risk clinical trials. Survival and stroke rates were compared after 90 CAS procedures in MHR patients vs 106 CAS procedures in normal risk patients. Survival results were also compared with 365 contemporaneous carotid endarterectomy (CEA) procedures in 346 patients. The mean age of CAS patients was 72 years, with 87% having a smoking history, 85% hypertension, 38% diabetes, 39% symptomatic, and 74% documented coronary artery disease. Mean follow-up was 23 months. Recurrent stenosis after CEA comprised 21% of all CAS procedures. During the 30-day post-procedure period, there were five minor strokes, one major stroke, and one death, for a combined stroke/death rate of 3.6%. Kaplan-Meier analysis demonstrated mortality of 5% at 1 year and 21% at 3 years for the entire cohort. Cox regression analysis found that MHR designation was not associated with increased mortality or an increase in a composite end point of death or stroke. MHR patients had mortality of 4% at 1 year and 22% at 3 years. Normal risk patients had mortality of 6% at 1 year and 20% at 3 years. Preoperative age over 80 years old, low density lipoprotein (LDL) > or =160 mg/dL, and serum creatinine > or =1.5 mg/dL conferred statistically significant risk for death (Hazard ratios: 2.9, 4.3, and 2.4, respectively). As a point of comparison, a contemporaneous group of CEA patients were analyzed similarly. After adjusting for age over 80 years old and serum creatinine > or =1.5 mg/dL, there was no survival difference between MHR patients undergoing CAS or CEA. The

  16. Simultaneous transfer of cholesterol, triglycerides, and phospholipids to high-density lipoprotein in aging subjects with or without coronary artery disease

    OpenAIRE

    AZEVEDO, Carolina H. M; Maurício Wajngarten; Ana C. Lo Prete; Jayme Diament; Raul C. Maranhão

    2011-01-01

    OBJECTIVE: To verify whether the capacity of high-density lipoprotein (HDL) to simultaneously receive non-esterified cholesterol, triglycerides, cholesteryl esters, and phospholipids changes with aging and the presence of coronary artery disease. DESIGN: Cross-sectional study with biochemical analyses. SUBJECTS: Eleven elderly patients with coronary artery disease (74±5 years) were compared with the following groups of non-coronary artery disease subjects (referred to as “healthy”): 25 young ...

  17. Arterial elasticity imaging: comparison of finite-element analysis models with high-resolution ultrasound speckle tracking

    Directory of Open Access Journals (Sweden)

    Park Dae

    2010-06-01

    Full Text Available Abstract Background The nonlinear mechanical properties of internal organs and tissues may be measured with unparalleled precision using ultrasound imaging with phase-sensitive speckle tracking. The many potential applications of this important noninvasive diagnostic approach include measurement of arterial stiffness, which is associated with numerous major disease processes. The accuracy of previous ultrasound measurements of arterial stiffness and vascular elasticity has been limited by the relatively low strain of nonlinear structures under normal physiologic pressure and the measurement assumption that the effect of the surrounding tissue modulus might be ignored in both physiologic and pressure equalized conditions. Methods This study performed high-resolution ultrasound imaging of the brachial artery in a healthy adult subject under normal physiologic pressure and the use of external pressure (pressure equalization to increase strain. These ultrasound results were compared to measurements of arterial strain as determined by finite-element analysis models with and without a surrounding tissue, which was represented by homogenous material with fixed elastic modulus. Results Use of the pressure equalization technique during imaging resulted in average strain values of 26% and 18% at the top and sides, respectively, compared to 5% and 2%, at the top and sides, respectively, under physiologic pressure. In the artery model that included surrounding tissue, strain was 19% and 16% under pressure equalization versus 9% and 13% at the top and sides, respectively, under physiologic pressure. The model without surrounding tissue had slightly higher levels of strain under physiologic pressure compared to the other model, but the resulting strain values under pressure equalization were > 60% and did not correspond to experimental values. Conclusions Since pressure equalization may increase the dynamic range of strain imaging, the effect of the

  18. Arterial and fat tissue inflammation are highly correlated: a prospective {sup 18}F-FDG PET/CT study

    Energy Technology Data Exchange (ETDEWEB)

    Bucerius, Jan [Mount Sinai School of Medicine, Translational and Molecular Imaging Institute, One Gustave L. Levy Place, P. O. Box 1234, New York, NY (United States); Mount Sinai School of Medicine, Department of Radiology, New York, NY (United States); Maastricht University Medical Center, Department of Nuclear Medicine, Maastricht (Netherlands); Maastricht University Medical Center, Cardiovascular Research Institute Maastricht (CARIM), Maastricht (Netherlands); University Hospital RWTH Aachen, Department of Nuclear Medicine, Aachen (Germany); Mani, Venkatesh; Fayad, Zahi A. [Mount Sinai School of Medicine, Translational and Molecular Imaging Institute, One Gustave L. Levy Place, P. O. Box 1234, New York, NY (United States); Mount Sinai School of Medicine, Department of Radiology, New York, NY (United States); Mount Sinai School of Medicine, Department of Cardiology, Zena and Michael A. Weiner Cardiovascular Institute and Marie-Josee and Henry R. Kravis Cardiovascular Health Center, New York, NY (United States); Wong, Stephanie; Moncrieff, Colin; Izquierdo-Garcia, David [Mount Sinai School of Medicine, Translational and Molecular Imaging Institute, One Gustave L. Levy Place, P. O. Box 1234, New York, NY (United States); Mount Sinai School of Medicine, Department of Radiology, New York, NY (United States); Machac, Josef [Mount Sinai School of Medicine, Division of Nuclear Medicine, Department of Radiology, New York, NY (United States); Fuster, Valentin [Mount Sinai School of Medicine, Department of Cardiology, Zena and Michael A. Weiner Cardiovascular Institute and Marie-Josee and Henry R. Kravis Cardiovascular Health Center, New York, NY (United States); The Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid (Spain); Farkouh, Michael E. [Mount Sinai School of Medicine, Department of Cardiology, Zena and Michael A. Weiner Cardiovascular Institute and Marie-Josee and Henry R. Kravis Cardiovascular Health Center, New York, NY (United States); Mount Sinai School of Medicine, Cardiovascular Imaging Clinical Trials Unit, New York, NY (United States); Rudd, James H.F. [University of Cambridge, Division of Cardiovascular Medicine, Cambridge (United Kingdom)

    2014-05-15

    There is evidence that the link between obesity and cardiovascular disease might relate to inflammation in both fat tissue and the arterial wall. {sup 18}F-FDG uptake on PET is a surrogate marker of vessel wall inflammation. The aim of the study was to measure FDG uptake in both regions using PET and identify links between adipose and arterial inflammation. Included in the study were 173 cardiovascular patients who were prospectively imaged with FDG PET/CT. Arterial FDG uptake was measured in the carotid arteries and ascending aorta. The same was done in fat tissue in the neck, the presternal region (both subcutaneous) and the pericardium. FDG uptake was quantified as average maximal target-to-background ratio ({sub mean}TBR{sub max}). Multivariate regression analyses were performed to identify significant associations between arterial and adipose tissue FDG uptake and clinical variables as given by the standardized correlation coefficient (β). FDG uptake values in all fat tissue regions were highly predictive of vascular FDG uptake in both the carotids (β 0.262, p < 0.0001, in the neck subcutaneous region) and aorta (β 0.22, p = 0.008, in the chest pericardial region; β 0.193, p = 0.019, in the chest subcutaneous region). Obesity was significantly associated with elevated FDG uptake in adipose tissue (β 0.470, p < 0.0001, in the neck subcutaneous region; β 0.619, p = 0.028, in the chest subcutaneous region; β 0.978, p = 0.035, in the chest pericardial region). FDG uptake in diverse fat tissue regions was significantly associated with arterial FDG uptake, a reasonable surrogate of inflammation. Increasing body weight significantly predicted the level of fatty inflammation. FDG PET therefore provides imaging evidence of an inflammatory link between fat tissue and the vasculature in patients with cardiovascular disease. (orig.)

  19. Comparison of end-tidal carbon dioxide and arterial blood bicarbonate levels in patients with metabolic acidosis referred to emergency medicine.

    Science.gov (United States)

    Taghizadieh, Ali; Pouraghaei, Mahboub; Moharamzadeh, Payman; Ala, Alireza; Rahmani, Farzad; Basiri Sofiani, Karim

    2016-01-01

    Introduction: The routine and gold standard method to diagnose of acid - base disturbance is arterial blood gas (ABG) sampling. Capnography could be used to measure the end-tidal carbon dioxide (ETCO2) levels and ETco2 has a close correlation with the PaCo2. The aim of this study was comparison the ETco2 and arterial blood bicarbonate levels in patients with metabolic acidosis. Methods: In a descriptive-analytical study that performed in Emergency Department of Emam Reza Medical Research and Training Hospital of Tabriz on patients with metabolic acidosis, ETco2 level and blood bicarbonate levels in 262 patients were evaluated. Results: Mean of ETco2 and Hco3 levels in patients with metabolic acidosis were 22.29 ± 4.15 and 12.78 ± 3.83, respectively. In all patients, the significant direct linear relationship was found between ETco2 with Hco3 (r = 0.553, P level of arterial blood in patients with renal failure (P < 0.001 and r = 0.551), sepsis (P < 0.001 and r = 0.431), drug toxicity (P < 0.001 and r = 0.856), and ketoacidosis (DKA) (P < 0.001 and r = 0.559). Conclusion: According to the results of this study, capnography can be used for primary diagnosis of metabolic acidosis in spontaneously breathing patients who referred to the emergency wards, however, the ABG must be considered as the gold standard tool for diagnosis and guiding the treatment.

  20. Kirishites, a new type of natural high-carbon compounds

    Science.gov (United States)

    Marin, Yu. B.; Skublov, G. T.; Yushkin, N. P.

    2010-01-01

    On the right-hand bank of the Volkhov River, in the natural area of tektite-like glasses (Volkhovites), fragments of shungites and slags with bunches of hairlike dark brownish enclosures were found. The filament thickness ranged from 20 to 100 μm, and separate “hairlines” were 3 cm in length. The composition of shungites and “hairlines” was found to be identical, which allowed us to consider the latter as aposhungite carbon formations. The high-carbon hairline structures associated with volkhovites are called kirishites. Kirishites are a new type of high-carbon structures that formed simultaneously with volkhovites in the case of explosion-type delivery of carbon slag and shungite fragments to the daylight surface during Holocene explosive activity. Under sharply reductive conditions, the slags partially melted, the melts were segregated, and carbonaceous-silicate and carbonaceous-ferriferous glasses formed with subsequent decompression-explosive liberation of carbon-supersaturated structures, which were extruded from shungite and slag fragments in the form of a resinoid mass. The “hairlines” were found to be zonal in structure: the central axial zones are composed of high-nitrogen hydrocarbon compounds, and peripheral regions are essentially carbonaceous with a high content of organic-mineral compounds and numerous microanomalies of petrogenic, volatile, rare, and ore elements. Infrared spectroscopy identified in kirishites proteinlike compounds, diagnosed in absorption bands (in cm-1) 600-720 (Amid V), 1200-1300 (Amid III), 1480-1590 (Amid II), 1600-1700 (Amid I), 3000-3800 (vibrations in NH2 and II groups). Gas chromatography, with the possibility of differentiation of left- and right-handed forms, revealed a broad spectrum of amino acids in kirishites, with their total content found to be the absolutely highest record for natural bitumens, an order of magnitude higher than the largest amino acid concentrations ever revealed in fibrous high

  1. High performance ultracapacitors with carbon nanomaterials and ionic liquids

    Science.gov (United States)

    Lu, Wen; Henry, Kent Douglas

    2012-10-09

    The present invention is directed to the use of carbon nanotubes and/or electrolyte structures in various electrochemical devices, such as ultracapacitors having an ionic liquid electrolyte. The carbon nanotubes are preferably aligned carbon nanotubes. Compared to randomly entangled carbon nanotubes, aligned carbon nanotubes can have better defined pore structures and higher specific surface areas.

  2. Carbon nanotube nanoweb-bioelectrode for highly selective dopamine sensing.

    Science.gov (United States)

    Zhao, Jie; Zhang, Weimin; Sherrell, Peter; Razal, Joselito M; Huang, Xu-Feng; Minett, Andrew I; Chen, Jun

    2012-01-01

    A highly sensitive and selective dopamine sensor was fabricated with the unique 3D carbon nanotube nanoweb (CNT-N) electrode. The as-synthesised CNT-N was modified by oxygen plasma to graft functional groups in order to increase selective electroactive sites at the CNT sidewalls. This electrode was characterized physically and electrochemically using HRSEM, Raman, FT-IR, and cyclic voltammetry (CV). Our investigations indicated that the O(2)-plasma treated CNT-N electrode could serve as a highly sensitive biosensor for the selective sensing of dopamine (DA, 1 μM to 20 μM) in the presence of ascorbic acid (AA, 1000 μM).

  3. The Tensile Behavior of High-Strength Carbon Fibers.

    Science.gov (United States)

    Langston, Tye

    2016-08-01

    Carbon fibers exhibit exceptional properties such as high stiffness and specific strength, making them excellent reinforcements for composite materials. However, it is difficult to directly measure their tensile properties and estimates are often obtained by tensioning fiber bundles or composites. While these macro scale tests are informative for composite design, their results differ from that of direct testing of individual fibers. Furthermore, carbon filament strength also depends on other variables, including the test length, actual fiber diameter, and material flaw distribution. Single fiber tensile testing was performed on high-strength carbon fibers to determine the load and strain at failure. Scanning electron microscopy was also conducted to evaluate the fiber surface morphology and precisely measure each fiber's diameter. Fiber strength was found to depend on the test gage length and in an effort to better understand the overall expected performance of these fibers at various lengths, statistical weak link scaling was performed. In addition, the true Young's modulus was also determined by taking the system compliance into account. It was found that all properties (tensile strength, strain to failure, and Young's modulus) matched very well with the manufacturers' reported values at 20 mm gage lengths, but deviated significantly at other lengths.

  4. Predictors of high on-aspirin platelet reactivity in elderly patients with coronary artery disease.

    Science.gov (United States)

    Zhang, J W; Liu, W W; McCaffrey, Timothy A; He, X Q; Liang, W Y; Chen, X H; Feng, X R; Fu, Sidney W; Liu, M L

    2017-01-01

    Previous studies have illustrated the link between high on-aspirin platelet reactivity (HAPR) with increasing thrombotic risks. The aim of our study was to investigate relative risk factors of HAPR in elderly patients with coronary artery disease. Elderly, hospitalized coronary artery disease patients on regular aspirin treatment were enrolled from January 2014 to September 2016. Medical records of each patient were collected, including demographic information, cardiovascular risk factors, concomitant drugs and routine biological parameters. Arachidonic acid (AA, 0.5 mg/mL) and adenosine diphosphate (ADP, 5 µmol/L) induced platelet aggregation were measured via light transmission assay (LTA) to evaluate antiplatelet responses, referred as LTA-AA and LTA-ADP. A total of 275 elderly patients were included, with mean age of 77.2±8.1 years, and males accounted for 81.8%. HAPR was defined as LTA-AA in the upper quartile of the enrolled population. HAPR patients tended to have lower renal function (P=0.052). Higher serum uric acid (SUA) level, as well as lower platelet count, hemoglobin and hematocrit were observed in HAPR patients, with a higher proportion of diuretics use (P<0.05). Multivariate analysis revealed that SUA (OR: 1.004, 95% CI: 1.000-1.007, P=0.048), platelet count (OR: 0.994, 95% CI: 0.989-1.000, P=0.045), hematocrit (OR: 0.921, 95% CI: 0.864-0.981, P=0.011) and concomitant P2Y12 receptor inhibitors use (OR: 1.965, 95% CI: 1.075-3.592, P=0.028) were correlated with HAPR. Spearman's correlation analysis demonstrated an inverse association of LTA-AA with hematocrit (r=-0.234, P<0.001), hemoglobin (r=-0.209, P<0.001) and estimated glomerular filtration rate (r=-0.132, P=0.031). SUA, platelet count, hematocrit and P2Y12 receptor inhibitors use were independently correlated with HAPR. These parameters might provide novel therapeutic targets for optimizing antiplatelet therapy.

  5. Feasibility of high-resolution MR imaging for the diagnosis of intracranial vertebrobasilar artery dissection

    Energy Technology Data Exchange (ETDEWEB)

    Han, Miran; Rim, Nae-Jung; Kim, Sun Yong; Choi, Jin Wook [Ajou University School of Medicine, Ajou University Medical Center, Department of Radiology, Suwon (Korea, Republic of); Lee, Jin Soo [Ajou University School of Medicine, Ajou University Medical Center, Department of Neurology, Suwon (Korea, Republic of)

    2014-12-15

    To evaluate the feasibility of high-resolution MRI (HR-MRI) for diagnosing intracranial vertebrobasilar artery dissection (VBD) and to identify the most useful imaging findings suggesting dissection. We retrospectively reviewed 50 patients with suspected intracranial VBDs who underwent HR-MRI. Two neuroradiologists independently reviewed the HR-MR images. The diagnosis based on HR-MRI was compared with the final diagnosis by consensus among the neuroradiologists, neurointerventionist, and neurologist. Two neuroradiologists also sought signs of dissection (mural hematoma, dissection flap, outer-diameter enlargement on T2WI of steno-occlusive lesions). Inter- and intraobserver agreements were analysed. HR-MRI corroborated the final diagnosis in 47 (94 %; 31 VBD and 16 non-VBD) patients. A mural haematoma was best detected on T1WI and contrast-enhanced (CE)-T1WI (54.3 %). Dissection flaps were observed in almost all cases on CE-T1WI (91.4 %), and then were detected on T2WI (68.6 %). Outer-diameter enlargement of the steno-occlusive lesions on angiography was detected in more than half of the cases (62.9 %). The two reviewers showed almost perfect agreement for the diagnosis of VBD and detecting dissection signs on every sequence. HR-MRI can be a useful and non-invasive diagnostic tool for intracranial VBD, and dissection flaps on CE-T1WI are the signs with the greatest diagnostic value. (orig.)

  6. Preoperative statin is associated with decreased operative mortality in high risk coronary artery bypass patients

    Directory of Open Access Journals (Sweden)

    Maher Thomas D

    2010-02-01

    Full Text Available Abstract Background Statins are widely prescribed to patients with atherosclerosis. A retrospective database analysis was used to examine the role of preoperative statin use in hospital mortality, for patients undergoing isolated coronary artery bypass grafting (CABG. Methods The study population comprised 2377 patients who had isolated CABG at Allegheny General Hospital between 2000 and 2004. Mean age of the patients was 65 ± 11 years (range 27 to 92 years. 1594 (67% were male, 5% had previous open heart procedures, and 4% had emergency surgery. 1004 patients (42% were being treated with a statin at the time of admission. Univariate, bivariate (Chi2, Fisher's Exact and Student's t-tests and multivariate (stepwise linear regression analyses were used to evaluate the association of statin use with mortality following CABG. Results Annual prevalence of preoperative statin use was similar over the study period and averaged 40%. Preoperative clinical risk assessment demonstrated a 2% risk of mortality in both the statin and non-statin groups. Operative mortality was 2.4% for all patients, 1.7% for statin users and 2.8% for non-statin users (p Conclusions Between 2000 and 2004 less than 50% of patients at this institution were receiving statins before admission for isolated CABG. A retrospective analysis of this cohort provides evidence that preoperative statin use is associated with lower operative mortality in high-risk patients.

  7. Unwinding of a carbon nanoscroll due to high speed rotation

    Directory of Open Access Journals (Sweden)

    Hang Yin

    2015-10-01

    Full Text Available A carbon nanoscroll (CNS can be formed easily by rolling a graphene sheet around a carbon nanotube (CNT [Zhang and Li, 2010, APL, 97, 081909]. When the CNS is driven by the rotary CNT to rotate at a high speed, the attractive interaction within the CNS or between the CNS and CNT is crippled by the centrifugal force on the CNS. The unwinding of CNS is triggered when the kinetic energy increment approaches to the variation of interaction energy of the system during CNS formation. Numerical experiments also indicate that the unwinding of CNS happens earlier when the CNT has a higher rotational speed or the system is at a higher temperature.

  8. Tailoring Carbon Nanostructure for High Frequency Supercapacitor Operation

    Directory of Open Access Journals (Sweden)

    Pritesh Hiralal

    2014-01-01

    Full Text Available The possibility of enhancing the frequency performance of electrochemical capacitors by tailoring the nanostructure of the carbon electrode to increase electrolyte permeability is demonstrated. Highly porous, vertically oriented carbon electrodes which are in direct electrical contact with the metallic current collector are produced via MPECVD growth on metal foils. The resulting structure has a capacitance and frequency performance between that of an electrolytic capacitor and an electrochemical capacitor. Fully packaged devices are produced on Ni and Cu current collectors and performance compared to state-of-the-art electrochemical capacitors and electrolytic capacitors. The extension of capacitive behavior to the AC regime (~100 Hz opens up an avenue for a number of new applications where physical volume of the capacitor may be significantly reduced.

  9. Highly efficient electroosmotic flow through functionalized carbon nanotube membranes

    Science.gov (United States)

    Wu, Ji; Gerstandt, Karen; Majumder, Mainak; Zhan, Xin; Hinds, Bruce J.

    2011-08-01

    Carbon nanotube membranes with inner diameter ranging from 1.5-7 nm were examined for enhanced electroosmotic flow. After functionalization via electrochemical diazonium grafting and carbodiimide coupling reaction, it was found that neutral caffeine molecules can be efficiently pumped via electroosmosis. An electroosmotic velocity as high as 0.16 cm s-1 V-1 has been observed. Power efficiencies were 25-110 fold improved compared to related nanoporous materials, which has important applications in chemical separations and compact medical devices. Nearly ideal electroosmotic flow was seen in the case where the mobile cation diameter nearly matched the inner diameter of the single-walled carbon nanotube resulting in a condition of using one ion is to pump one neutral molecule at equivalent concentrations.

  10. The CH fraction of Carbon stars at high Galactic latitudes

    CERN Document Server

    Goswami, Aruna; Shantikumar, N S

    2009-01-01

    CH stars form a distinct class of objects with characteristic properties like iron deficiency, enrichment of carbon and overabundance in heavy elements. These properties can provide strong observational constraints for theoretical computation of nucleosynthesis at low-metallicity. An important question is the relative surface density of CH stars which can provide valuable inputs to our understanding on the role of low to intermediate-mass stars in the early Galactic chemical evolution. Spectroscopic characterization provides an effective way of identifying CH stars. The present analysis is aimed at a quantitative assessment of the fraction of CH stars in a sample of stars using a set of spectral classification criteria. The sample consists of 92 objects selected from a collection of candidate Faint High Latitude Carbon stars from the Hamburg/ESO survey. Medium resolution (R ~ 1300) spectra for these objects were obtained using OMR at VBO, Kavalur and HFOSC at HCT, IAO, Hanle, during 2007 - 2009 spanning a wav...

  11. Clinical Outcomes After Drug-Eluting Stents Versus Coronary Artery Bypass Surgery in High Surgical Risk Patients With Left Main or Three-Vessel Coronary Artery Disease

    Directory of Open Access Journals (Sweden)

    Tonga Nfor

    2015-08-01

    Full Text Available Purpose: Previous studies comparing percutaneous coronary intervention (PCI with coronary artery bypass graft surgery (CABG in patients with unprotected left main or three-vessel coronary artery disease (LM-3VD have excluded patients at high surgical risk. We compared clinical outcomes after PCI with drug-eluting stents to CABG in high surgical risk patients with LM-3VD. Methods: Patients with symptomatic LM-3VD who had Society of Thoracic Surgeons (STS-predicted operative mortality > 5% and were undergoing either PCI with drug-eluting stents or CABG at a tertiary care center from January 2009 to December 2010 were enrolled in this nonrandomized prospective study. Results: Mean STS score was 14.5 ± 5.8% for PCI (n=83 vs. 13.6 ± 7.1% for CABG (n=187 (P=0.31. After mean follow-up of 37 months, incidence of the composite primary endpoint (death, myocardial infarction or stroke was 42.2% for PCI and 39.6% for CABG (P=0.69, hazard ratio 1.3, 95% confidence interval 0.5-2.8. There were no differences in the individual components of the primary endpoint between PCI and CABG. Repeat revascularization was 30.1% for PCI vs. 9.6% for CABG (P=0.001. Major adverse cardiac and cerebrovascular event rates were similar between PCI and CABG, 50.6% vs. 42.2%, respectively (P=0.23. Patients in the PCI group were less likely than those in the CABG group to be discharged to a nursing home (12.1% vs. 47.1%, P 5%.

  12. Carbon nanotube transistor based high-frequency electronics

    Science.gov (United States)

    Schroter, Michael

    At the nanoscale carbon nanotubes (CNTs) have higher carrier mobility and carrier velocity than most incumbent semiconductors. Thus CNT based field-effect transistors (FETs) are being considered as strong candidates for replacing existing MOSFETs in digital applications. In addition, the predicted high intrinsic transit frequency and the more recent finding of ways to achieve highly linear transfer characteristics have inspired investigations on analog high-frequency (HF) applications. High linearity is extremely valuable for an energy efficient usage of the frequency spectrum, particularly in mobile communications. Compared to digital applications, the much more relaxed constraints for CNT placement and lithography combined with already achieved operating frequencies of at least 10 GHz for fabricated devices make an early entry in the low GHz HF market more feasible than in large-scale digital circuits. Such a market entry would be extremely beneficial for funding the development of production CNTFET based process technology. This talk will provide an overview on the present status and feasibility of HF CNTFET technology will be given from an engineering point of view, including device modeling, experimental results, and existing roadblocks. Carbon nanotube transistor based high-frequency electronics.

  13. A high performance silicon/carbon composite anode with carbon nanofiber for lithium-ion batteries

    Science.gov (United States)

    Si, Q.; Hanai, K.; Ichikawa, T.; Hirano, A.; Imanishi, N.; Takeda, Y.; Yamamoto, O.

    The electrochemical performance of a composite of nano-Si powder and a pyrolytic carbon of polyvinyl chloride (PVC) with carbon nanofiber (CNF) was examined as an anode for lithium-ion batteries. CNF was incorporated into the composite by two methods; direct mixing of CNF with the nano-Si powder coated with carbon produced by pyrolysis of PVC (referred to as Si/C/CNF-1) and mixing of CNF, nano-Si powder, and PVC with subsequent firing (referred to as Si/C/CNF-2). The external Brunauer-Emmett-Teller (BET) surface area of Si/C/CNF-1 was comparable to that of Si/C/CNF-2. The micropore BET surface area of Si/C/CNF-2 (73.86 m 2 g -1) was extremely higher than that of Si/C/CNF-1 (0.74 m 2 g -1). The composites prepared by both methods exhibited high capacity and excellent cycling stability for lithium insertion and extraction. A capacity of more than 900 mA h g -1 was maintained after 30 cycles. The coulombic efficiency of the first cycle for Si/C/CNF-1 was as low as 53%, compared with 73% for Si/C/CNF-2. Impedance analysis of cells containing these anode materials suggested that the charge transfer resistance for Si/C/CNF-1 was not changed by cycling, but that Si/C/CNF-2 had high charge transfer resistance after cycling. A composite electrode prepared by mixing Si/C/CNF-2 and CNF exhibited a high reversible capacity at high rate, excellent cycling performance, and a high coulombic efficiency during the first lithium insertion and extraction cycles.

  14. Characterization and synthesis of carbon aggregates in high temperature environment

    OpenAIRE

    2013-01-01

    Carbon materials in all its forms, from the natural carbon solid materials, as coal and graphite, to the synthesized carbon materials, as carbon black, pitch fibers, fullerenes, carbon nanotubes, etc,. have been object of many studies regarding their characteristics and behaviour due to their importance in the energy and industrial sectors. Recently, most of the research efforts have been focused on the synthesis of new carbon materials and in particular on their physico-chemical propertie...

  15. High oxygen modifies vasodilator effect of cysteine via enhanced oxidative stress and thromboxane production in the rat mesenteric artery.

    Science.gov (United States)

    Yasuda, Yoshitaka; Feng, Guo-Gang; Li, Jiazheng; Nakamura, Emi; Hayashi, Hisaki; Sato, Motohiko; Fujiwara, Yoshihiro; Kinoshita, Hiroyuki

    2016-09-01

    Whether high oxygen is harmful to the vascular function is unclear. The present study examined if high oxygen modifies vasodilator effect of cysteine via enhanced oxidative stress and thromboxane production. Rat mesenteric arteries with endothelium at 95 or 50 % oxygen were subjected to isometric force recordings, measurement of thromboxane B2 levels, determination of superoxide and peroxynitrite levels and evaluation of NADPH oxidase subunit protein expression, respectively. L-cysteine (0.01-3 mM) constricted or dilated arteries at 95 and 50 % oxygen, respectively. Thromboxane receptor antagonist SQ-29,548 (1 μM) abolished the constriction at 95 % oxygen. L-cysteine (3 mM) increased levels of thromboxane B2 in arteries upon 95 % oxygen application. L-cysteine relaxed arteries treated with superoxide inhibitor tiron (2 mM) or NADPH oxidase inhibitor gp91ds-tat (1 μM) irrespective of the oxygen concentration while ATP-sensitive K(+) channel inhibitor glibenclamide (1 μM) and cystathionine-γ-lyase (CSE) inhibitor DL-propargylglycine (10 mM) similarly abolished the relaxation. L-cysteine (3 mM) with 95 % oxygen augmented levels of superoxide as well as nitrotyrosine within the artery, concomitantly with enhanced membrane protein expression of NADPH oxidase subunit p47phox. The higher concentration of oxygen attenuates L-cysteine-induced vasodilation via superoxide production mediated by NADPH oxidase along with thromboxane A2 production, resulting in vasoconstriction. The increased levels of superoxide, as well as peroxynitrite, coexist with the impaired vasodilation related to ATP-sensitive K(+) channels and CSE. Higher oxygen with plasma cysteine may cause oxidative stress and vasoconstrictor prostanoid production in blood vessels.

  16. [Upper extremity arterial diseases].

    Science.gov (United States)

    Becker, F

    2007-02-01

    Compared to lower limb arterial diseases, upper limb arterial diseases look rare, heterogeneous with various etiologies and a rather vague clinical picture, but with a negligible risk of amputation. Almost all types of arterial diseases can be present in the upper limb, but the anatomical and hemodynamic conditions particular to the upper limb often confuse the issue. Thus, atherosclerosis affects mainly the subclavian artery in its proximal segment where the potential of collateral pathway is high making the symptomatic forms not very frequent whereas the prevalence of subclavian artery stenosis or occlusion is relatively high. The clinical examination and the etiologies are discussed according to the clinical, anatomical and hemodynamic context.

  17. High-pitch dual-source CT angiography of supra-aortic arteries: assessment of image quality and radiation dose

    Energy Technology Data Exchange (ETDEWEB)

    Korn, A.; Fenchel, M.; Bender, B.; Danz, S.; Ernemann, U. [Department of Diagnostic und Interventional Neuroradiology, Tuebingen (Germany); Thomas, C.; Ketelsen, D.; Claussen, C.D.; Heuschmid, M. [Department of Diagnostic und Interventional Radiology, Tuebingen (Germany); Moonis, G. [Beth Israel Deaconess Medical Center, Department of Radiology, Boston, MA (United States); Krauss, B. [Siemens AG, Imaging and Therapy Division, Forchheim (Germany); Brodoefel, H. [Department of Diagnostic und Interventional Radiology, Tuebingen (Germany); Beth Israel Deaconess Medical Center, Department of Radiology, Boston, MA (United States); Harvard Medical School, Beth Israel Deaconess Medical Center, Boston, MA (United States)

    2013-04-15

    High-pitch CT angiography (CTA) is a recent innovation that allows significant shortening of scan time with volume coverage of 43 mm per second. The aim of our study was to assess this technique in CTA of the head and neck. CTA of supra-aortic arteries was performed in 50 patients using two acquisition protocols: conventional single-source 64-slice (pitch 1.2) and high-pitch dual-source 128-slice CT (pitch 3.2). Subjective and objective image quality of supra-aortic vessel ostia as well as intra- and extra-cranial segments was retrospectively assessed by blinded readers and radiation dose compared between the two protocols. Conventional and high-pitch CTA achieved comparable signal-to-noise ratios in arterial (54.3 {+-} 16.5 versus 57.3 {+-} 14.8; p = 0.50) and venous segments (15.8 {+-} 6.7 versus 18.9 {+-} 8.9; p = 0.21). High-pitch scanning was, however, associated with sharper delineation of vessel contours and image quality significantly improved at the level of supra-aortic vessel ostia (p < 0.0001) as well as along the brachiocephalic trunk (p < 0.0001), the subclavian arteries (p < 0.0001), proximal common carotid arteries (p = 0.01), and vertebral V1 segments (p < 0.0001). Using the high-pitch mode, the dose-length product was reduced by about 35 % (218.2 {+-} 30 versus 141.8 {+-} 20 mGy x cm). Due to elimination of transmitted cardiac motion, high-pitch CTA of the neck improves image quality in the proximity of the aortic arch while significantly lowering radiation dose. The technique thus qualifies as a promising alternative to conventional spiral CTA and may be particularly useful for identification of ostial stenosis. (orig.)

  18. Ocean Urea Fertilization for Carbon Credits Poses High Ecological Risks

    Science.gov (United States)

    Glibert, Patricia M.; Azanza, Rhodora; Burford, Michele; Furuya, Ken; Abal, Eva; Al-Azri, Adnan; Al-Yamani, Faiza; Andersen, Per; Beardall, John; Berg, G. Mine; Brand, Larry; Bronk, Deborah; Brookes, Justin; Burkholder, JoAnn M.; Cembella, Allan; Cochlan, William P.; Collier, Jackie; Collos, Yves; Diaz, Robert; Doblin, Martina; Drennen, Thomas; Dyhrman, Sonya; Fukuyo, Yasuwo; Furnas, Miles; Galloway, James; Granéli, Edna; Ha, Dao Viet; Hallegraeff, Gustaaf; Harrison, John; Harrison, Paul J.; Heil, Cynthia A.; Heimann, Kirsten; Howarth, Robert; Jauzein, Cécile; Kana, Austin A.; Kana, Todd M.; Kim, Hakgyoon; Kudela, Raphael; Legrand, Catherine; Mallin, Michael; Mulholland, Margaret; Murray, Shauna; O’Neil, Judith; Pitcher, Grant; Qi, Yuzao; Rabalais, Nancy; Raine, Robin; Seitzinger, Sybil; Solomon, Caroline; Stoecker, Diane K.; Usup, Gires; Wilson, Joanne; Yin, Kedong; Zhou, Mingjiang; Zhu, Mingyuan

    2017-01-01

    The proposed plan for enrichment of the Sulu Sea, Philippines, a region of rich marine biodiversity, with thousands of tonnes of urea in order to stimulate algal blooms and sequester carbon is flawed for multiple reasons. Urea is preferentially used as a nitrogen source by some cyanobacteria and dinoflagellates, many of which are neutrally or positively buoyant. Biological pumps to the deep sea are classically leaky, and the inefficient burial of new biomass makes the estimation of a net loss of carbon from the atmosphere questionable at best. The potential for growth of toxic dinoflagellates is also high, as many grow well on urea and some even increase their toxicity when grown on urea. Many toxic dinoflagellates form cysts which can settle to the sediment and germinate in subsequent years, forming new blooms even without further fertilization. If large-scale blooms do occur, it is likely that they will contribute to hypoxia in the bottom waters upon decomposition. Lastly, urea production requires fossil fuel usage, further limiting the potential for net carbon sequestration. The environmental and economic impacts are potentially great and need to be rigorously assessed. PMID:18439628

  19. Ocean urea fertilization for carbon credits poses high ecological risks.

    Science.gov (United States)

    Glibert, Patricia M; Azanza, Rhodora; Burford, Michele; Furuya, Ken; Abal, Eva; Al-Azri, Adnan; Al-Yamani, Faiza; Andersen, Per; Anderson, Donald M; Beardall, John; Berg, G Mine; Brand, Larry; Bronk, Deborah; Brookes, Justin; Burkholder, Joann M; Cembella, Allan; Cochlan, William P; Collier, Jackie L; Collos, Yves; Diaz, Robert; Doblin, Martina; Drennen, Thomas; Dyhrman, Sonya; Fukuyo, Yasuwo; Furnas, Miles; Galloway, James; Granéli, Edna; Ha, Dao Viet; Hallegraeff, Gustaaf; Harrison, John; Harrison, Paul J; Heil, Cynthia A; Heimann, Kirsten; Howarth, Robert; Jauzein, Cécile; Kana, Austin A; Kana, Todd M; Kim, Hakgyoon; Kudela, Raphael; Legrand, Catherine; Mallin, Michael; Mulholland, Margaret; Murray, Shauna; O'Neil, Judith; Pitcher, Grant; Qi, Yuzao; Rabalais, Nancy; Raine, Robin; Seitzinger, Sybil; Salomon, Paulo S; Solomon, Caroline; Stoecker, Diane K; Usup, Gires; Wilson, Joanne; Yin, Kedong; Zhou, Mingjiang; Zhu, Mingyuan

    2008-06-01

    The proposed plan for enrichment of the Sulu Sea, Philippines, a region of rich marine biodiversity, with thousands of tonnes of urea in order to stimulate algal blooms and sequester carbon is flawed for multiple reasons. Urea is preferentially used as a nitrogen source by some cyanobacteria and dinoflagellates, many of which are neutrally or positively buoyant. Biological pumps to the deep sea are classically leaky, and the inefficient burial of new biomass makes the estimation of a net loss of carbon from the atmosphere questionable at best. The potential for growth of toxic dinoflagellates is also high, as many grow well on urea and some even increase their toxicity when grown on urea. Many toxic dinoflagellates form cysts which can settle to the sediment and germinate in subsequent years, forming new blooms even without further fertilization. If large-scale blooms do occur, it is likely that they will contribute to hypoxia in the bottom waters upon decomposition. Lastly, urea production requires fossil fuel usage, further limiting the potential for net carbon sequestration. The environmental and economic impacts are potentially great and need to be rigorously assessed.

  20. Pool boiling with high heat flux enabled by a porous artery structure

    Science.gov (United States)

    Bai, Lizhan; Zhang, Lianpei; Lin, Guiping; Peterson, G. P.

    2016-06-01

    A porous artery structure utilizing the concept of "phase separation and modulation" is proposed to enhance the critical heat flux of pool boiling. A series of experiments were conducted on a range of test articles in which multiple rectangular arteries were machined directly into the top surface of a 10.0 mm diameter copper rod. The arteries were then covered by a 2.0 mm thickness microporous copper plate through silver brazing. The pool wall was fabricated from transparent Pyrex glass to allow a visualization study, and water was used as the working fluid. Experimental results confirmed that the porous artery structure provided individual flow paths for the liquid supply and vapor venting, and avoided the detrimental effects of the liquid/vapor counter flow. As a result, a maximum heat flux of 610 W/cm2 over a heating area of 0.78 cm2 was achieved with no indication of dryout, prior to reaching the heater design temperature limit. Following the experimental tests, the mechanisms responsible for the boiling critical heat flux and performance enhancement of the porous artery structure were analyzed.

  1. Method for the preparation of high surface area high permeability carbons

    Science.gov (United States)

    Lagasse, R.R.; Schroeder, J.L.

    1999-05-11

    A method for preparing carbon materials having high surface area and high macropore volume to provide high permeability. These carbon materials are prepared by dissolving a carbonizable polymer precursor, in a solvent. The solution is cooled to form a gel. The solvent is extracted from the gel by employing a non-solvent for the polymer. The non-solvent is removed by critical point drying in CO{sub 2} at an elevated pressure and temperature or evaporation in a vacuum oven. The dried product is heated in an inert atmosphere in a first heating step to a first temperature and maintained there for a time sufficient to substantially cross-link the polymer material. The cross-linked polymer material is then carbonized in an inert atmosphere. 3 figs.

  2. Method for the preparation of high surface area high permeability carbons

    Energy Technology Data Exchange (ETDEWEB)

    Lagasse, Robert R. (Albuquerque, NM); Schroeder, John L. (Albuquerque, NM)

    1999-05-11

    A method for preparing carbon materials having high surface area and high macropore volume to provide high permeability. These carbon materials are prepared by dissolving a carbonizable polymer precursor, in a solvent. The solution is cooled to form a gel. The solvent is extracted from the gel by employing a non-solvent for the polymer. The non-solvent is removed by critical point drying in CO.sub.2 at an elevated pressure and temperature or evaporation in a vacuum oven. The dried product is heated in an inert atmosphere in a first heating step to a first temperature and maintained there for a time sufficient to substantially cross-link the polymer material. The cross-linked polymer material is then carbonized in an inert atmosphere.

  3. Nonalcoholic Hepatic Steatosis Is a Strong Predictor of High-Risk Coronary-Artery Plaques as Determined by Multidetector CT.

    Directory of Open Access Journals (Sweden)

    Kazuhiro Osawa

    Full Text Available Nonalcoholic fatty liver disease is associated with a risk of coronary artery disease (e.g., diabetes mellitus, dyslipidemia, metabolic syndrome. We evaluated whether nonalcoholic hepatic steatosis is associated with high-risk plaques as assessed by multidetector computed tomography (CT.This retrospective study involved 414 participants suspected of having coronary artery disease. Nonalcoholic hepatic steatosis was defined as a liver-to-spleen fat ratio of <1.0 and the presence and appropriate characteristics of coronary-artery plaques as assessed by coronary CT angiography. High-risk plaques were identified, as were low-density plaques, positive remodeling, and spotty calcification.Compared with patients who did not have nonalcoholic hepatic steatosis, patients with nonalcoholic hepatic steatosis had more low-density plaques (21% vs. 44%, p<0.01, positive remodeling (41% vs. 58%, p = 0.01, and spotty calcification (12% vs. 36%, p<0.01. The number of high-risk plaques in patients with nonalcoholic hepatic steatosis was greater than in those without nonalcoholic hepatic steatosis (p<0.01. Patients with nonalcoholic hepatic steatosis were more likely to have high-risk plaques than were those with only an elevated level of visceral adipose tissue (≥86 cm2; 35% vs. 16%, p<0.01. Multivariate analyses that included nonalcoholic hepatic steatosis, amount of visceral adipose tissue, and the presence/absence of traditional risk factors demonstrated that nonalcoholic hepatic steatosis was an independent predictor of high-risk plaques (odds ratio: 4.60; 95% confidence interval: 1.94-9.07, p<0.01.Diagnosis of nonalcoholic hepatic steatosis may be of value when assessing the risk of coronary artery disease.

  4. Nanoporous Carbon Nitride: A High Efficient Filter for Seawater Desalination

    CERN Document Server

    Li, Weifeng; Zhou, Hongcai; Zhang, Xiaoming; Zhao, Mingwen

    2015-01-01

    The low efficiency of commercially-used reverse osmosis (RO) membranes has been the main obstacle in seawater desalination application. Here, we report the auspicious performance, through molecular dynamics simulations, of a seawater desalination filter based on the recently-synthesized graphene-like carbon nitride (g-C2N) [Nat. Commun., 2015, 6, 6486]. Taking advantage of the inherent nanopores and excellent mechanical properties of g-C2N filter, highly efficient seawater desalination can be achieved by modulating the nanopores under tensile strain. The water permeability can be improved by two orders of magnitude compared to RO membranes, which offers a promising approach to the global water shortage solution.

  5. Nanosecond pulsed laser welding of high carbon steels

    Science.gov (United States)

    Ascari, Alessandro; Fortunato, Alessandro

    2014-03-01

    The present paper deals with the possibility to exploit low-cost, near infra-red, nanosecond pulsed laser sources in welding of high carbon content thin sheets. The exploitation of these very common sources allows to achieve sound weld beads with a good depth-to-width ratio and very small heat affected zones when the proper process parameters are involved. In particular the role of pulse frequency, pulse duration, peak power and welding speed on the characteristics of the weld beads is studied and the advantage of the application of short-pulse laser sources over traditional long-pulse or continuous wave one is assessed.

  6. High Energy Radial Deposition of Diamond-Like Carbon Coatings

    Directory of Open Access Journals (Sweden)

    Konrad Suschke

    2015-07-01

    Full Text Available Diamond-like carbon (DLC coatings were deposited with a new direct ion deposition system using a novel 360 degree ion source operating at acceleration voltage between 4 and 8 kV. Cross-sectional TEM images show that the coatings have a three layered structure which originates from changes in the deposition parameters taking into account ion source condition, ion current density, deposition angles, ion sputtering and ion source movement. Varying structural growth conditions can be achieved by tailoring the deposition parameters. The coatings show good promise for industrial use due to their high hardness, low friction and excellent adhesion to the surface of the samples.

  7. Hybrid Friction Stir Welding of High-carbon Steel

    Institute of Scientific and Technical Information of China (English)

    Don-Hyun Choi; Seung-Boo Jung; Chang-Yong Lee; Byung-Wook Ahn; Jung-Hyun Choi; Yun-Mo Yeon; Keun Song; Seung-Gab Hong; Won-Bae Lee; Ki-Bong Kang

    2011-01-01

    A high-carbon steel joint, SK5 (0.84 wt% C), was successfully welded by friction stir welding (FSW), both without and with a gas torch, in order to control the cooling rate during welding. After welding, the weld zone comprised gray and black regions, corresponding to microstructural variation: a martensite structure and a duplex structure of ferrite and cementite, respectively. The volume fraction of the martensite structure and the Vickers hardness in the welds were decreased with the using of the gas torch, which was related with the lower cooling rate.

  8. Effects of the transcutaneous electrode temperature on the accuracy of transcutaneous carbon dioxide tension

    DEFF Research Database (Denmark)

    Sørensen, Line C; Brage-Andersen, Lene; Greisen, Gorm

    2011-01-01

    The harmful effect of hypocapnia on the neonatal brain emphasizes the importance of monitoring arterial carbon dioxide tension (PaCO2). Transcutaneous monitoring of carbon dioxide (tcPCO2) reduces the need for arterial blood sampling. Drawbacks are high electrode temperature causing risks of skin...

  9. High Black Carbon (BC) Concentrations along Indian National Highways

    Science.gov (United States)

    Kumar, S.; Singh, A. K.; Singh, R. P.

    2015-12-01

    Abstract:Black carbon (BC), the optically absorbing component of carbonaceous aerosol, has direct influence on radiation budget and global warming. Vehicular pollution is one of the main sources for poor air quality and also atmospheric pollution. The number of diesel vehicles has increased on the Indian National Highways during day and night; these vehicles are used for the transport of goods from one city to another city and also used for public transport. A smoke plume from the vehicles is a common feature on the highways. We have made measurements of BC mass concentrations along the Indian National Highways using a potable Aethalometer installed in a moving car. We have carried out measurements along Varanasi to Kanpur (NH-2), Varanasi to Durgapur (NH-2), Varanasi to Singrauli (SH-5A) and Varanasi to Ghazipur (NH-29). We have found high concentration of BC along highways, the average BC mass concentrations vary in the range 20 - 40 µg/m3 and found high BC mass concentrations up to 600 μg/m3. Along the highways high BC concentrations were characteristics of the presence of industrial area, power plants, brick kilns and slow or standing vehicles. The effect of increasing BC concentrations along the National Highways and its impact on the vegetation and human health will be presented. Key Words: Black Carbon; Aethalometer; mass concentration; Indian National Highways.

  10. High Temperature Mechanical Testing of a Cylindrical Weave Carbon-Carbon Composite.

    Science.gov (United States)

    2014-09-26

    S. Los Angeles CA 90009 AEROSPACE CORPORATION Feldman L. Los Angeles CA 90009 AEROSPACE CORPORATION Meyer Robert A. Los Angeles CA 90009 AEROSPACE...and Feldman found no appreciable creep w i th the same specimens before reach i nq a temperature of 22:0 C,:. ref 7) The in-house axial specimens...Materials" , Technical report AFrL-TR-77-94, June 1977. (8) L.A. Feldman , "High Temperature Creep of Carbon Yarns: First Annual Report", ONR Annual Report

  11. Climate Based Performance of Carbon-Carbon Disc Brake for High Speed Aircraft Braking System

    Directory of Open Access Journals (Sweden)

    R. M. Mohanty

    2013-09-01

    Full Text Available Carbon composite brake discs are lighter, economical, and have excellent high energy friction characteristics. These have twice thermal capability compared to steel, remain unaffected by thermal shocks and mechanical fatigue. These are highly useful in emergency breaking situations. Prior to this work, two dimensional (2D reinforced carbon composite laminates were prepared through pitch impregnation process. In an effort to protect the exposed non frictional surface from high temperature service degradations, multilayered ceramic coating systems were developed on 2D composite. Oxidation studies have been carried out on these systems viz., C-SiC, C-SiC-MoSi2-Al2O3 and C-SiC-B4C. These were performed both in dynamic and static conditions up to 1200 °C in 60 per cent humid climate. The hardness, surface topography, developed phases and integrity of layers on the samples at various stages of the experiment have been characterized and analyzed. It was observed that C-SiC-B4C system performs well in the oxidizing environment.Defence Science Journal, 2013, 63(5, pp.531-538, DOI:http://dx.doi.org/10.14429/dsj.63.3932

  12. Going High with Heart Disease: The Effect of High Altitude Exposure in Older Individuals and Patients with Coronary Artery Disease.

    Science.gov (United States)

    Levine, Benjamin D

    2015-06-01

    Levine, Benjamin D. Going high with heart disease: The effect of high altitude exposure in older individuals and patients with coronary artery disease. High Alt Med Biol 16:89-96, 2015.--Ischemic heart disease is the largest cause of death in older men and women in the western world (Lozano et al., 2012 ; Roth et al., 2015). Atherosclerosis progresses with age, and thus age is the dominant risk factor for coronary heart disease in any algorithm used to assess risk for cardiovascular events. Subclinical atherosclerosis also increases with age, providing the substrate for precipitation of acute coronary syndromes. Thus the risk of high altitude exposure in older individuals is linked closely with both subclinical and manifest coronary heart disease (CHD). There are several considerations associated with taking patients with CHD to high altitude: a) The reduced oxygen availability may cause or exacerbate symptoms; b) The hypoxia and other associated environmental conditions (exercise, dehydration, change in diet, thermal stress, emotional stress from personal danger or conflict) may precipitate acute coronary events; c) If an event occurs and the patient is far from advanced medical care, then the outcome of an acute coronary event may be poor; and d) Sudden death may occur. Physicians caring for older patients who want to sojourn to high altitude should keep in mind the following four key points: 1). Altitude may exacerbate ischemic heart disease because of both reduced O2 delivery and paradoxical vasoconstriction; 2). Adverse events, including acute coronary syndromes and sudden cardiac death, are most common in older unfit men, within the first few days of altitude exposure; 3). Ensuring optimal fitness, allowing for sufficient acclimatization (at least 5 days), and optimizing medical therapy (especially statins and aspirin) are prudent recommendations that may reduce the risk of adverse events; 4). A graded exercise test at sea level is probably sufficient for

  13. Matrix metalloproteinase-2 and -9 are associated with high stresses predicted using a nonlinear heterogeneous model of arteries.

    Science.gov (United States)

    Kim, Yu Shin; Galis, Zorina S; Rachev, Alexander; Han, Hai-Chao; Vito, Raymond P

    2009-01-01

    Arteries adapt to their mechanical environment by undergoing remodeling of the structural scaffold via the action of matrix metalloproteinases (MMPs). Cell culture studies have shown that stretching vascular smooth muscle cells (VSMCs) positively correlates to the production of MMP-2 and -9. In tissue level studies, the expressions and activations of MMP-2 and -9 are generally higher in the outer media. However, homogeneous mechanical models of arteries predict lower stress and strain in the outer media, which appear inconsistent with experimental findings. The effects of heterogeneity may be important to our understanding of VSMC function since arteries exhibit structural heterogeneity across the wall. We hypothesized that local stresses, computed using a heterogeneous mechanical model of arteries, positively correlate to the levels of MMP-2 and -9 in situ. We developed a model of the arterial wall accounting for nonlinearity, residual strain, anisotropy, and structural heterogeneity. The distributions of elastin and collagen fibers in situ, measured in the media of porcine carotid arteries, showed significant nonuniformities. Anisotropy was represented by the direction of collagen fibers measured by the helical angle of VSMC nuclei. The points at which the collagen fibers became load bearing were computed, assuming a uniform fiber strain and orientation under physiological loading conditions, an assumption motivated by morphological measurements. The distributions of circumferential stresses, computed using both heterogeneous and homogeneous models, were correlated to the distributions of expressions and activations of MMP-2 and -9 in porcine common carotid arteries incubated in an ex vivo perfusion organ culture system under physiological conditions for 48 h. While strains computed using incompressibility were identical in both models, the heterogeneous model, unlike the homogeneous model, predicted higher circumferential stresses in the outer layer correlated

  14. High accuracy of arterial spin labeling perfusion imaging in differentiation of pilomyxoid from pilocytic astrocytoma

    Energy Technology Data Exchange (ETDEWEB)

    Nabavizadeh, S.A.; Assadsangabi, R.; Hajmomenian, M.; Vossough, A. [Perelman School of Medicine of the University of Pennsylvania, Department of Radiology, Children' s Hospital of Philadelphia, Philadelphia, PA (United States); Santi, M. [Perelman School of Medicine of the University of Pennsylvania, Department of Pathology, Children' s Hospital of Philadelphia, Philadelphia, PA (United States)

    2015-05-01

    Pilomyxoid astrocytoma (PMA) is a relatively new tumor entity which has been added to the 2007 WHO Classification of tumors of the central nervous system. The goal of this study is to utilize arterial spin labeling (ASL) perfusion imaging to differentiate PMA from pilocytic astrocytoma (PA). Pulsed ASL and conventional MRI sequences of patients with PMA and PA in the past 5 years were retrospectively evaluated. Patients with history of radiation or treatment with anti-angiogenic drugs were excluded. A total of 24 patients (9 PMA, 15 PA) were included. There were statistically significant differences between PMA and PA in mean tumor/gray matter (GM) cerebral blood flow (CBF) ratios (1.3 vs 0.4, p < 0.001) and maximum tumor/GM CBF ratio (2.3 vs 1, p < 0.001). Area under the receiver operating characteristic (ROC) curves for differentiation of PMA from PA was 0.91 using mean tumor CBF, 0.95 using mean tumor/GM CBF ratios, and 0.89 using maximum tumor/GM CBF. Using a threshold value of 0.91, the mean tumor/GM CBF ratio was able to diagnose PMA with 77 % sensitivity, 100 % specificity, and a threshold value of 0.7, provided 88 % sensitivity and 86 % specificity. There was no statistically significant difference between the two tumors in enhancement pattern (p = 0.33), internal architecture (p = 0.15), or apparent diffusion coefficient (ADC) values (p = 0.07). ASL imaging has high accuracy in differentiating PMA from PA. The result of this study may have important applications in prognostication and treatment planning especially in patients with less accessible tumors such as hypothalamic-chiasmatic gliomas. (orig.)

  15. High prevalence of peripheral arterial disease in patients with previous cerebrovascular or coronary event

    DEFF Research Database (Denmark)

    Mehlsen, Jesper; Wiinberg, Niels; Joergensen, Bjarne S

    2010-01-01

    The presence of peripheral arterial disease (PAD) in patients with other manifestations of cardiovascular disease identifies a population at increased risk of complications both during acute coronary events and on a long-term basis and possibly a population in whom secondary prevention of cardiov......The presence of peripheral arterial disease (PAD) in patients with other manifestations of cardiovascular disease identifies a population at increased risk of complications both during acute coronary events and on a long-term basis and possibly a population in whom secondary prevention...

  16. The Impact of Moderate-Altitude Staging on Pulmonary Arterial Hemodynamics after Ascent to High Altitude

    Science.gov (United States)

    2010-01-01

    pressure ( Pao2 ) and arterial oxygenation saturation (Sao2) were measured at each time point. Compared to mean PAP at SL (mean SD, 14 3 mmHg), mean PAP...increased after DA to 37 8 mmHg (D¼ 24 10 mmHg, p< 0.001) and was negatively correlated with both Pao2 (r 2¼ 0.57, p¼ 0.011) and Sao2 (r2¼ 0.64, p...subcostal view. Assessment of oxygenation The primary indexes of oxygenation in this study were alveolar oxygen pressure ( Pao2 ) and arterial oxygen

  17. An unusual case of left aberrant innominate artery with right aortic arch: evaluation with high-resolution CT

    Energy Technology Data Exchange (ETDEWEB)

    Calcagni, Giulio [University Rene Descartes-Paris 5, Department of Pediatric Cardiology, Hopital Necker Enfants Malades, Paris (France); Gesualdo, Francesco; Brunelle, Francis; Ou, Phalla [University Rene Descartes-Paris 5, Department of Pediatric Radiology, Hopital Necker Enfants Malades, Paris Cedex 15 (France)

    2008-01-15

    A left aberrant innominate (brachiocephalic) artery is an angiographically well-known entity that may cause tracheal compression. We report a male newborn who was admitted for further investigation of a prenatally suspected major vessel anomaly. High-resolution CT was used to completely assess the abnormal anatomy and the relationship with the airway, as well as to guide the surgical approach for its correction. (orig.)

  18. Effects of vinylene carbonate on high temperature storage of high voltage Li-ion batteries

    Science.gov (United States)

    Eom, Ji-Yong; Jung, In-Ho; Lee, Jong-Hoon

    The effects of vinylene carbonate (VC) on high temperature storage of high voltage Li-ion batteries are investigated. 1.3 M of LiPF 6 dissolved in ethylene carbonate (EC), ethylmethyl carbonate (EMC) and dimethyl carbonate (DMC) of 3:3:4 volume ratio is used as original electrolyte for 18650 cylindrical cells with LiCoO 2 cathode and graphite anode. VC is then added to electrolyte. At the initial stage of the high temperature storage, higher open-circuit voltage (OCV) is maintained when increasing the VC concentration. As the storage time increases, OCV of higher VC concentration drops gradually, and then the gas evolution takes place abruptly. Gas analysis shows methane (CH 4) decreases with increase of the VC concentration due to formation of stable solid electrolyte interface (SEI) layer on the graphite. Since the residual VC after formation of the SEI layer decomposes on the cathode surface, carbon dioxide (CO 2) dramatically increases on the cathode with the VC concentration, leaving poly(VC) film at the anode surface, as suggested by XPS test results.

  19. NOVEL INORGANIC MEMBRANES FOR HIGH TEMPERATURE CARBON DIOXIDE SEPARATION

    Energy Technology Data Exchange (ETDEWEB)

    Jerry Y.S. Lin

    2003-02-01

    We studied feasibility of two types of dense inorganic membranes which are fundamentally different from those porous inorganic membranes reported in the literature for separation of carbon dioxide from gas streams at high temperatures. The first is a symmetric, dense membrane made of Li{sub 2}ZrO{sub 3} and the second is a dual-phase metal-carbonate membrane. We have identified a unique CO{sub 2} sorption/desorption mechanism on lithium zirconate. Considering the all obtained data, we proposed a double layer model to describe the CO{sub 2} sorption/desorption behavior of lithium zirconate. In the model, final product after CO{sub 2} sorption is a particle which consists of a ZrO{sub 2} core inside and a Li{sub 2}CO{sub 3} shell. The understanding of CO{sub 2} sorption mechanisms suggests a means to improve CO{sub 2} sorption rate on this group of oxides. It also leads to the conclusion that lithium zirconate is not a suitable material for the proposed dense ceramic membrane for CO{sub 2} separation. Following the second concept of dense membrane for CO{sub 2} separation, we succeeded in preparing the hermetic (gas-tight) dense inorganic membrane consisting of a porous metal phase and a molten carbonate phase. The metal phase not only provides the mechanical support but also is electronically conducting, reducing the overall mass transfer resistance for CO{sub 2} permeation through the membrane. Permeation data showed that nitrogen or helium is not permeable through these membranes (only CO{sub 2}, with O{sub 2}, can permeate through the membrane based on the transport mechanism). This dual-phase membrane may offer promising properties for applications in membrane processes for separation of CO{sub 2} from flue (or coal gasification gas) at high temperatures (350-550 C).

  20. Coronary artery calcium score using electron beam tomography in the patients with acute obstructive coronary arterial disease : comparative study within asymptomatic high-risk group of atherosclerosis and chronic obstructive coronary arterial disease group

    Energy Technology Data Exchange (ETDEWEB)

    Ryu, Seok Jong; Choi, Byoung Wook; Choe, Kyu Ok [Yonsei Univ. College of Medicine, Seoul (Korea, Republic of)

    2001-04-01

    To compare, through analysis of the coronary artery calcium (CAC) score and the risk factors for atherosclerosis, the characteristics of acute coronary syndrome between an asymptomatic high-risk group of atherosclerosis patients and a chronic coronary arterial obstructive disease(CAOD) group. The CAC scores of an asymptomatic high-risk group of atherosclerosis patients (group I, n=284), a chronic CAOD croup (group II, n=39) and an acute coronary syndrome group (group III, n=21) were measured by electron beam tomography. Forty-seven patients with CAOD from groups II and III underwent coronary angiography, and we scrutinized age, sex and risk factors including diabetes mellitus, hypertension, obesity, smoking, hypercholesterolemia and low high-density lipoproteinemia. The numbers of stenotic coronary arterial branches and degree of stenosis revealed by coronary angiography were also recorded. We determined the differences between the three groups in terms of CAC score and the risk factors, the relationship between CAC score and risk factors, and the characteristic features of each type of CAOD group. The mean CA score of group III (135.1) was not statistically different from that of group I (135.7) or group II (365.8). Among patients aged below 50, the mean CAC score of group III (127.4) was significantly higher than that of group I (6.2), (p=0.0006). The mean CAC score at the sixth decade was also significantly different between group I(81.5) and group II (266.9). The mean age of group III (54.2 years) was significantly lower than that of group I (58.1 years) (p=0.047) and of group II (60.1) (p=0.022). There was significant correlation between the number of stenotic coronary arterial branches and log(CAC +1) (p<.01). The square root of the CAC score and the maximal degree of stenosis was also well correlated (p<.01). There was no difference in the mean number of risk factors among the three groups, though the incidence of smoking in group III was significantly

  1. Soot Nanostructure: Using Fringe Analysis Software on High Resolution Transmission Electron Microscopy of Carbon Soot

    Science.gov (United States)

    King, James D.

    2004-01-01

    Using high resolution transmission electron images of carbon nanotubes and carbon particles, we are able to use image analysis program to determine several carbon fringe properties, including length, separation, curvature and orientation. Results are shown in the form of histograms for each of those quantities. The combination of those measurements can give a better indication of the graphic structure within nanotubes and particles of carbon and can distinguish carbons based upon fringe properties. Carbon with longer, straighter and closer spaced fringes are considered graphite, while amorphous carbon contain shorter, less structured fringes.

  2. Functional Carbon Nanotube/Mesoporous Carbon/MnO2 Hybrid Network for High-Performance Supercapacitors

    Directory of Open Access Journals (Sweden)

    Tao Tao

    2014-01-01

    Full Text Available A functional carbon nanotube/mesoporous carbon/MnO2 hybrid network has been developed successfully through a facile route. The resulting composites exhibited a high specific capacitance of 351 F/g at 1 A g−1, with intriguing charge/discharge rate performance and cycling stability due to a synergistic combination of large surface area and excellent electron-transport capabilities of MnO2 with the good conductivity of the carbon nanotube/mesoporous carbon networks. Such composite shows great potential to be used as electrodes for supercapacitors.

  3. Nitrogen-doped mesoporous carbons for high performance supercapacitors

    Science.gov (United States)

    Wu, Kai; Liu, Qiming

    2016-08-01

    The mesoporous carbons have been synthesized by using α-D(+)-Glucose, D-Glucosamine hydrochloride or their mixture as carbon precursors and mesoporous silicas (SBA-15 or MCF) as hard templates. The as-prepared products show a large pore volume (0.59-0.97 cm3 g-1), high surface areas (352.72-1152.67 m2 g-1) and rational nitrogen content (ca. 2.5-3.9 wt.%). The results of electrochemical tests demonstrate that both heteroatom doping and suitable pore structure play a decisive role in the performance of supercapacitors. The representative sample of SBA-15 replica obtained using D-Glucosamine hydrochloride only exhibits high specific capacitance (212.8 F g-1 at 0.5 A g-1) and good cycle durability (86.1% of the initial capacitance after 2000 cycles) in 6 M KOH aqueous electrolyte, which is attributed to the contribution of double layer capacitance and pseudo-capacitance. The excellent electrochemical performance makes it a promising electrode material for supercapacitors.

  4. Manufacturing High-Quality Carbon Nanotubes at Lower Cost

    Science.gov (United States)

    Benavides, Jeanette M.; Lidecker, Henning

    2004-01-01

    A modified electric-arc welding process has been developed for manufacturing high-quality batches of carbon nanotubes at relatively low cost. Unlike in some other processes for making carbon nanotubes, metal catalysts are not used and, consequently, it is not necessary to perform extensive cleaning and purification. Also, unlike some other processes, this process is carried out at atmospheric pressure under a hood instead of in a closed, pressurized chamber; as a result, the present process can be implemented more easily. Although the present welding-based process includes an electric arc, it differs from a prior electric-arc nanotube-production process. The welding equipment used in this process includes an AC/DC welding power source with an integral helium-gas delivery system and circulating water for cooling an assembly that holds one of the welding electrodes (in this case, the anode). The cathode is a hollow carbon (optionally, graphite) rod having an outside diameter of 2 in. (approximately equal to 5.1 cm) and an inside diameter of 5/8 in. (approximately equal to 1.6 cm). The cathode is partly immersed in a water bath, such that it protrudes about 2 in. (about 5.1 cm) above the surface of the water. The bottom end of the cathode is held underwater by a clamp, to which is connected the grounding cable of the welding power source. The anode is a carbon rod 1/8 in. (approximately equal to 0.3 cm) in diameter. The assembly that holds the anode includes a thumbknob- driven mechanism for controlling the height of the anode. A small hood is placed over the anode to direct a flow of helium downward from the anode to the cathode during the welding process. A bell-shaped exhaust hood collects the helium and other gases from the process. During the process, as the anode is consumed, the height of the anode is adjusted to maintain an anode-to-cathode gap of 1 mm. The arc-welding process is continued until the upper end of the anode has been lowered to a specified height

  5. High absolute risks and predictors of venous and arterial thromboembolic events in patients with nephrotic syndrome

    NARCIS (Netherlands)

    Mahmoodi, Bakhtawar K.; ten Kate, Min Ki; Waanders, Femke; Veeger, Nic J. G. M.; Brouwer, Jan-Leendert P.; Vogt, Liffert; Navis, Gerjan; van der Meer, Jan

    2008-01-01

    Background-No data are available on the absolute risk of either venous thromboembolism (VTE) or arterial thromboembolism (ATE) in patients with nephrotic syndrome. Reported risks are based on multiple case reports and small studies with mostly short-term follow-up. We assessed the absolute risk of V

  6. Fabrication of highly conductive carbon nanotube fibers for electrical application

    Science.gov (United States)

    Guo, Fengmei; Li, Can; Wei, Jinquan; Xu, Ruiqiao; Zhang, Zelin; Cui, Xian; Wang, Kunlin; Wu, Dehai

    2015-09-01

    Carbon nanotubes (CNTs) have great potential for use as electrical wires because of their outstanding electrical and mechanical properties. Here, we fabricate lightweight CNT fibers with electrical conductivity as high as that of stainless steel from macroscopic CNT films by drawing them through diamond wire-drawing dies. The entangled CNT bundles are straightened by suffering tension, which improves the alignment of the fibers. The loose fibers are squeezed by the diamond wire-drawing dies, which reduces the intertube space and contact resistance. The CNT fibers prepared by drawing have an electrical conductivity as high as 1.6 × 106 s m-1. The fibers are very stable when kept in the air and under cyclic tensile test. A prototype of CNT motor is demonstrated by replacing the copper wires with the CNT fibers.

  7. The Use of the Ratio between the Veno-arterial Carbon Dioxide Difference and the Arterial-venous Oxygen Difference to Guide Resuscitation in Cardiac Surgery Patients with Hyperlactatemia and Normal Central Venous Oxygen Saturation

    Institute of Scientific and Technical Information of China (English)

    Wei Du; Yun Long; Xiao-Ting Wang; Da-Wei Liu

    2015-01-01

    Background:After cardiac surgery,central venous oxygen saturation (ScvO2) and serum lactate concentration are often used to guide resuscitation;however,neither are completely reliable indicators of global tissue hypoxia.This observational study aimed to establish whether the ratio between the veno-arterial carbon dioxide and the arterial-venous oxygen differences (P(v-a)CO2/C(a-v)O2) could predict whether patients would respond to resuscitation by increasing oxygen delivery (DO2).Methods:We selected 72 patients from a cohort of 290 who had undergone cardiac surgery in our institution between January 2012 and August 2014.The selected patients were managed postoperatively on the Intensive Care Unit,had a normal ScvO2,elevated serum lactate concentration,and responded to resuscitation by increasing DO2 by >10%.As a consequence,48 patients responded with an increase in oxygen consumption (VO2) while VO2 was static or fell in 24.Results:At baseline and before resuscitative intervention in postoperative cardiac surgery patients,a P(v-a)CO2/C(a-v)O2 ratio ≥1.6 mmHg/ml predicted a positive VO2 response to an increase in DO2 of>1 0% with a sensitivity of 68.8% and a specificity of 87.5%.Conclusions:P(v-a)CO2/C(a-v)O2 ratio appears to be a reliable marker of global anaerobic metabolism and predicts response to DO2 challenge.Thus,patients likely to benefit from resuscitation can be identified promptly,the P(v-a)CO2/C(a-v)O2 ratio may,therefore,be a useful resuscitation target.

  8. Energy Saving High-Capacity Moderate Pressure Carbon Dioxide Storage System Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Our approach to high-pressure carbon dioxide storage will directly address the challenges associated with storage of compressed carbon dioxide - the need to reduce...

  9. Retraction Statement: Unrecognized High Brachial Artery Bifurcation is Associated with Higher Rate of Dialysis Access by Dr. Lee Kirksey.

    Science.gov (United States)

    2017-03-01

    The above article from Seminars in Dialysis, published online on 4 September 2011 in Wiley Online Library (http://wileyonlinelibrary.com) has been retracted by agreement among the journal's Editor-in-Chief, Richard A. Sherman MD, the journal's North American editor of ASDIN content at the time, Arif Asif MD, and Wiley Periodicals, Inc. The decision to retract was agreed upon following notification by Dr. HeeJun Yang, the author of an article published in 2008, "Variations of the Superficial Brachial Artery in Korean Cadavers." Figure 1 (A & B) and Figure 2 (A-C) in the Kirksey article (1), which originally appeared in the 2008 article by Dr. Yang, were used without authorization or permission from Dr. Yang or the article's publisher. Reference Kirksey L: Unrecognized high brachial artery bifurcation is associated with higher rate of dialysis access. Semin Dial 24(6):698-702, 2011. doi: 10.1111/j.1525-139X.2011.00923.x.

  10. Comparison of end-tidal carbon dioxide and arterial blood bicarbonate levels in patients with metabolic acidosis referred to emergency medicine

    Science.gov (United States)

    Taghizadieh, Ali; Pouraghaei, Mahboub; Moharamzadeh, Payman; Ala, Alireza; Rahmani, Farzad; Basiri Sofiani, Karim

    2016-01-01

    Introduction: The routine and gold standard method to diagnose of acid – base disturbance is arterial blood gas (ABG) sampling. Capnography could be used to measure the end-tidal carbon dioxide (ETCO2) levels and ETco2 has a close correlation with the PaCo2. The aim of this study was comparison the ETco2 and arterial blood bicarbonate levels in patients with metabolic acidosis. Methods: In a descriptive-analytical study that performed in Emergency Department of Emam Reza Medical Research and Training Hospital of Tabriz on patients with metabolic acidosis, ETco2 level and blood bicarbonate levels in 262 patients were evaluated. Results: Mean of ETco2 and Hco3 levels in patients with metabolic acidosis were 22.29 ± 4.15 and 12.78 ± 3.83, respectively. In all patients, the significant direct linear relationship was found between ETco2 with Hco3 (r = 0.553, P < 0.001). We had 4 groups of patients with metabolic acidosis, also there is a significant direct linear relationship between the ETCo2 and the Hco3 level of arterial blood in patients with renal failure (P < 0.001 and r = 0.551), sepsis (P < 0.001 and r = 0.431), drug toxicity (P < 0.001 and r = 0.856), and ketoacidosis (DKA) (P < 0.001 and r = 0.559). Conclusion: According to the results of this study, capnography can be used for primary diagnosis of metabolic acidosis in spontaneously breathing patients who referred to the emergency wards, however, the ABG must be considered as the gold standard tool for diagnosis and guiding the treatment. PMID:27777693

  11. High performance carbon nanotube - polymer nanofiber hybrid fabrics

    Science.gov (United States)

    Yildiz, Ozkan; Stano, Kelly; Faraji, Shaghayegh; Stone, Corinne; Willis, Colin; Zhang, Xiangwu; Jur, Jesse S.; Bradford, Philip D.

    2015-10-01

    Stable nanoscale hybrid fabrics containing both polymer nanofibers and separate and distinct carbon nanotubes (CNTs) are highly desirable but very challenging to produce. Here, we report the first instance of such a hybrid fabric, which can be easily tailored to contain 0-100% millimeter long CNTs. The novel CNT - polymer hybrid nonwoven fabrics were created by simultaneously electrospinning nanofibers onto aligned CNT sheets which were drawn and collected on a grounded, rotating mandrel. Due to the unique properties of the CNTs, the hybrids show very high tensile strength, very small pore size, high specific surface area and electrical conductivity. In order to further examine the hybrid fabric properties, they were consolidated under pressure, and also calendered at 70 °C. After calendering, the fabric's strength increased by an order of magnitude due to increased interactions and intermingling with the CNTs. The hybrids are highly efficient as aerosol filters; consolidated hybrid fabrics with a thickness of 20 microns and areal density of only 8 g m-2 exhibited ultra low particulate (ULPA) filter performance. The flexibility of this nanofabrication method allows for the use of many different polymer systems which provides the opportunity for engineering a wide range of nanoscale hybrid materials with desired functionalities.Stable nanoscale hybrid fabrics containing both polymer nanofibers and separate and distinct carbon nanotubes (CNTs) are highly desirable but very challenging to produce. Here, we report the first instance of such a hybrid fabric, which can be easily tailored to contain 0-100% millimeter long CNTs. The novel CNT - polymer hybrid nonwoven fabrics were created by simultaneously electrospinning nanofibers onto aligned CNT sheets which were drawn and collected on a grounded, rotating mandrel. Due to the unique properties of the CNTs, the hybrids show very high tensile strength, very small pore size, high specific surface area and electrical

  12. Arterial hypoxaemia in cirrhosis

    DEFF Research Database (Denmark)

    Møller, S; Hillingsø, Jens; Christensen, E

    1998-01-01

    BACKGROUND: Although low arterial oxygen tension (Po2) has been claimed to occur in one to two thirds of patients with cirrhosis, hypoxaemia appears to be rare in clinical practice. AIMS: To assess the frequency of arterial hypoxaemia in cirrhosis in relation to clinical and haemodynamic......%, 96%, 96%, and 93% (NS). So2 was below the lower limit of 92% in 0%, 9%, 7%, and 24% (p arterial carbon dioxide tension, a low systemic vascular...... resistance, and a low indocyanine green clearance (p arterial hypoxaemia in cirrhosis is about 22% in patients without encephalopathy, but it varies from 10-40% depending on the degree of hepatic dysfunction. Arterial hypoxaemia in patients with cirrhosis of differing...

  13. Brain nonoxidative carbohydrate consumption is not explained by export of an unknown carbon source: evaluation of the arterial and jugular venous metabolome

    DEFF Research Database (Denmark)

    Rasmussen, Peter; Nyberg, Nils; Jaroszewski, Jerzy W.;

    2010-01-01

    Brain activation provokes nonoxidative carbohydrate consumption and during exercise it is dominated by the cerebral uptake of lactate resulting in that up to approximately 1 mmol/ 100 g of glucose equivalents cannot be accounted for by cerebral oxygen uptake. The fate of this 'extra' carbohydrate...... uptake is unknown, but it may be that brain metabolism is balanced by a yet-unidentified substance(s). This study used a nuclear magnetic resonance-based metabolomics approach to plasma samples obtained from the brachial artery and the right internal jugular vein in 16 healthy young males to identify...... carbon species going to and from the brain. We observed a carbohydrate accumulation of 255+/-37 micromol/100 g glucose equivalents at exhaustion not accounted for by the oxygen uptake. Although the cumulated uptake was lower than earlier observed, the results show that glucose and lactate are responsible...

  14. Reduced arterial diameter during static exercise in humans

    DEFF Research Database (Denmark)

    Olesen, H L; Mitchell, J H; Friedman, D B

    1995-01-01

    of another limb. Static exercise increased heart rate and mean arterial pressure, which were largest during one-leg knee extension. After exercise heart rate and mean arterial pressure returned to the resting level. No changes were recorded in arterial carbon dioxide tension, and the rate of perceived......In eight subjects luminal diameter of the resting limb radial and dorsalis pedis arteries was determined by high-resolution ultrasound (20 MHz). This measurement was followed during rest and during 2 min of static handgrip or of one-leg knee extension at 30% of maximal voluntary contraction...... exertion was approximately 15 units after both types of exercise. The dorsalis pedis arterial diameter was 1.50 +/- 0.20 mm (mean and SE) and the radial AD 2.45 +/- 0.12 mm. During both types of contractions the luminal diameters decreased approximately 3.5% within the first 30 s (P

  15. How to map soil carbon stocks in highly urbanized regions?

    Science.gov (United States)

    Vasenev, V. I.; Stoorvogel, J. J.

    2012-04-01

    Soil organic carbon (SOC) is the largest carbon stock in terrestrial ecosystems and the capacity for carbon sequestration is a widely accepted soil function. For land-use planning and decision making the regional analysis of SOC stocks and their spatial variability is an important and challenging task that receives increasing attention. Quite a few studies focus on mapping the carbon stocks in natural and agricultural areas using digital soil mapping (DSM) techniques. Although urban areas remain almost neglected. The urban environment provides a number of specific features and processes that influence soil formation and functioning: soil sealing, functional zoning and settlement history. This not only results in a considerable urban SOC (especially in the subsoil), but also results in a unique spatial variability of SOC stocks at short distance. In contrast to the often gradual changes in natural areas, urban soils may exhibit abrupt changes due to the anthropogenic influence. Thus implementation of standard DSM methodology will result in extremely high nuggets and correspondingly low prediction accuracy. Besides, traditional regression kriging, widely-used for the case when legacy data is lacking, is often based on the correlation between SOC and dominating soil forming factors (climate, relief, parent material and vegetation). Although in urban conditions, anthropogenic influence itself turns out to be a predominant soil-forming factor. The spatial heterogeneity of urban soil carbon stocks is further complicated by a specific profile distribution with possible second SOC maximum, referred to cultural layer. Importance of urban SOC as well as specifics of urban environment requires for a specific approach to map urban SOC as part of regional analysis. Moscow region with its variability of bioclimatic conditions and high urbanization level (10 % from the total area) was chosen as an interesting case study. Random soil sampling in different soil zones (4) and land

  16. The "T-MIDCAB" procedure. Use of extension grafts from the undisturbed internal mammary artery in high-risk patients.

    Science.gov (United States)

    Coulson, A S; Bakhshay, S A

    1998-01-01

    Minimally invasive direct coronary artery bypass grafting (MIDCAB) is an attractive new alternative for revascularizing patients with high perioperative risk for standard coronary surgery. However, limited surgical exposure through a small thoracotomy makes harvesting the full length of the internal mammary artery (IMA) very difficult and time consuming. We are now employing a new alternative with a "T" shaped bridge graft constructed from the undisturbed IMA using a 4 centimeter interposition segment of donor vessel. We prefer this approach in high risk cases in order to reduce the trauma of the thoracotomy, minimize pain and narcotic use, promote early extubation, and achieve immediate post-operative mobilization and recovery in patients who would otherwise be at risk for a poor outcome with conventional grafting techniques. From September 10, 1997 to December 19, 1997 eight high-risk patients underwent at least one "T-MIDCAB" graft from the undisturbed IMA to the coronary artery using a short segment of either radial artery or saphenous vein. All cases were performed using a limited access anterior thoracotomy through the bed of the resected costal cartilage and without intercostal retraction. Five males and three females ranging from 58 to 83 years (average 73 years) were operated using this new concept. Pre-operative ejection fractions ranged from 25% to 80% (mean 43%). Parsonnet scores ranged from 21 to 43 (average 34) with predicted mortalities ranging from 30 to 40%. Eleven "T" grafts were placed (1.38 distals/patient). All 8 patients survived. Postoperative complications were minimal. The average length of stay was only 8 days (range 3 to 9 days). Intensive care unit stay averaged 3 days (range 1 to 4 days). One patient underwent postoperative angiography which demonstrated full patency of the conduit and all anastomoses. "T-MIDCAB" using a bridge graft of free radial artery or saphenous vein appears to be successful in high risk patients. The authors

  17. Rapid removal of bisphenol A on highly ordered mesoporous carbon

    Institute of Scientific and Technical Information of China (English)

    Qian Sui; Jun Huang; Yousong Liu; Xiaofeng Chang; Guangbin Ji; Shubo Deng; Tao Xie; Gang Yu

    2011-01-01

    Bisphenol A (BPA) is of global concern due to its disruption of endocrine systems and ubiquity in the aquatic environment. It is important, therefore, that efforts are made to remove it from the aqueous phase. A novel adsorbent, mesoporous carbon CMK-3,prepared from hexagonal SBA-15 mesoporous silica was studied for BPA removal from aqueous phase, and compared with conventional powdered activated carbon (PAC). Characterization of CMK-3 by transmission electron microscopy (TEM), X-ray diffraction, and nitrogen adsorption indicated that prepared CMK-3 had an ordered mesoporous structure with a high specific surface area of 920 m2/g and a pore-size of about 4.9 nm. The adsorption of BPA on CMK-3 followed a pseudo second-order kinetic model. The kinetic constant was 0.00049 g/(mg·min), much higher than the adsorption of BPA on PAC. The adsorption isotherm fitted slightly better with the Freundlich model than the Langmuir model, and adsorption capacity decreased as temperature increased from 10 to 40℃.No significant influence of pH on adsorption was observed at pH 3 to 9; however, adsorption capacity decreased dramatically from pH 9to 13.

  18. High Performance Palladium Supported on Nanoporous Carbon under Anhydrous Condition

    Science.gov (United States)

    Yang, Zehui; Ling, Ying; Zhang, Yunfeng; Xu, Guodong

    2016-11-01

    Due to the high cost of polymer electrolyte fuel cells (PEFCs), replacing platinum (Pt) with some inexpensive metal was carried out. Here, we deposited palladium nanoparticles (Pd-NPs) on nanoporous carbon (NC) after wrapping by poly[2,2‧-(2,6-pyridine)-5,5‧-bibenzimidazole] (PyPBI) doped with phosphoric acid (PA) and the Pd-NPs size was successfully controlled by varying the weight ratio between Pd precursor and carbon support doped with PA. The membrane electrode assembly (MEA) fabricated from the optimized electrocatalyst with 0.05 mgPd cm‑2 for both anode and cathode sides showed a power density of 76 mW cm‑2 under 120 °C without any humidification, which was comparable to the commercial CB/Pt, 89 mW cm‑2 with 0.45 mgPt cm‑2 loaded in both anode and cathode. Meanwhile, the power density of hybrid MEA with 0.45 mgPt cm‑2 in cathode and 0.05 mgPd cm‑2 in anode reached 188 mW cm‑2. The high performance of the Pt-free electrocatalyst was attributed to the porous structure enhancing the gas diffusion and the PyPBI-PA facilitating the proton conductivity in catalyst layer. Meanwhile, the durability of Pd electrocatalyst was enhanced by coating with acidic polymer. The newly fabricated Pt-free electrocatalyst is extremely promising for reducing the cost in the high-temperature PEFCs.

  19. Does high altitude increase risks of the elderly patients with coronary artery disease?

    Institute of Scientific and Technical Information of China (English)

    Tian-Yi Wu; Zhong-Yan Zhan; Qin-Li Wu; Suo-Lung Baomu; Yu-Ling Jie; Min Sun

    2009-01-01

    Objective To assess the effect of altitude hypoxia on the elderly patients with coronary artery disease (CAD). Methods Three subject groups were surveyed during their train trip on the highest railroad--the Qinghai-Tibet Railway: 22 elderly individuals with documented CAD, 20 healthy elderly controls, and 20 healthy young controls, all of whom from Beijing near the sea level (76 m). Survey questions addressed clinical features of their healthy conditions and aspects of their coronary disease. The baseline study was performed at Xining at an altitude of 2261 m, and then during acute exposure to altitudes of 2808 m, 4768m, 5072 m and 4257 m by train for 24 hours. Resting pulse rate, blood pressure, oxygen saturation, electrocardiograph (ECG), and cardiac work estimated by the heart rate-blood pressure double product were obtained five times in each subject at different altitudes. Results On arrival to altitudes between 4768 m and 5072 m, the older passengers, especially those with preexisting coronary disease, had higher HR, higher BP, and lower SaO2, as well as more frequent abnormalities on ECG, as compared to the younger healthy subjects. As compared with the healthy elderly controls, incomplete right bundle branch block, left ventricular hypertrophy, and ST segment depression were more frequently seen in the elderly coronary patients (P<0.01). Cardiac work in group 1 was increased by 13% 12 hours after arrival to altitudes between 2808 m and 5072 m. Oxygen saturation decreased significantly with the altitude increasing by train ascent but improved after inhalation of oxygen. Most of the older subjects tolerated their sojourn at high altitude well except one who developed angina repeatedly with a significant ST segment depression. Conclusions Coronary events and ECG signs of myocardial ischemia are rare in elderly individuals with CAD who travel from sea level to moderate altitudes of 1500m to 2800 m. Patients with CAD who are well compensated at sea level

  20. Lightweight, Ultra-High-Temperature, CMC-Lined Carbon/Carbon Structures

    Science.gov (United States)

    Wright, Matthew J.; Ramachandran, Gautham; Williams, Brian E.

    2011-01-01

    Carbon/carbon (C/C) is an established engineering material used extensively in aerospace. The beneficial properties of C/C include high strength, low density, and toughness. Its shortcoming is its limited usability at temperatures higher than the oxidation temperature of carbon . approximately 400 C. Ceramic matrix composites (CMCs) are used instead, but carry a weight penalty. Combining a thin laminate of CMC to a bulk structure of C/C retains all of the benefits of C/C with the high temperature oxidizing environment usability of CMCs. Ultramet demonstrated the feasibility of combining the light weight of C/C composites with the oxidation resistance of zirconium carbide (ZrC) and zirconium- silicon carbide (Zr-Si-C) CMCs in a unique system composed of a C/C primary structure with an integral CMC liner with temperature capability up to 4,200 F (.2,315 C). The system effectively bridged the gap in weight and performance between coated C/C and bulk CMCs. Fabrication was demonstrated through an innovative variant of Ultramet fs rapid, pressureless melt infiltration processing technology. The fully developed material system has strength that is comparable with that of C/C, lower density than Cf/SiC, and ultra-high-temperature oxidation stability. Application of the reinforced ceramic casing to a predominantly C/C structure creates a highly innovative material with the potential to achieve the long-sought goal of long-term, cyclic high-temperature use of C/C in an oxidizing environment. The C/C substructure provided most of the mechanical integrity, and the CMC strengths achieved appeared to be sufficient to allow the CMC to perform its primary function of protecting the C/C. Nozzle extension components were fabricated and successfully hot-fire tested. Test results showed good thermochemical and thermomechanical stability of the CMC, as well as excellent interfacial bonding between the CMC liner and the underlying C/C structure. In particular, hafnium-containing CMCs on

  1. High precipitation rate in a Middle Triassic carbonate platform: Implications on the relationship between seawater saturation state and carbonate production

    Science.gov (United States)

    Franceschi, Marco; Preto, Nereo; Marangon, Alessandro; Gattolin, Giovanni; Meda, Marco

    2016-06-01

    Three-dimensional geological modeling of the Middle Triassic Latemar carbonate platform is coupled with facies modal analysis to estimate its carbonate precipitation rate (G). The 3D model, strongly constrained by field data, encompasses a specific stratigraphic interval of the platform, bounded by two isochronous surfaces. Modal analysis of thin sections allows estimating the proportion of syndepositional vs postdepositional carbonate in the facies associations of the platform. This, together with the 3D facies distribution in the model that takes into account lateral and vertical facies variability, permits to calculate the volumes of syndepositional carbonate preserved at Latemar between the two considered isochrones. Given the peculiar characteristics of the platform, that does not show evidences of strong dissolution processes or large carbonate mass loss through export in the nearby basins, results can be used to estimate the average precipitation rate of the platform in the considered time interval. This estimate allows discussion in relation to models of ocean water saturation state (Ω) with respect to carbonates in the geological past, and comparison to the calculated precipitation rates of modern tropical coral reef ecosystems at global and reef scale. A high G value is found at Latemar and represents the first empirical confirmation that, in the Triassic, extremes in Ω may have triggered high carbonate precipitation in shallow water settings; moreover, comparison to modern reefs points to a possible common relationship that may link seawater Ω and precipitation rate in carbonate platform ecosystems through geological time.

  2. Analysis of the population at high risk of stroke detected with carotid artery ultrasonography in Tianjin urban communities

    Directory of Open Access Journals (Sweden)

    Wei YUE

    2015-04-01

    Full Text Available Objective To investigate the features of carotid atherosclerosis in a population at high risk of stroke in urban communities of Tianjin, so as to provide inspiration for carotid ultrasonography to play a greater role in the prevention and control of stroke.  Methods A total of 956 residents at high risk of stroke were selected from 4 urban communities in Tianjin using cluster random sampling method. Doppler ultrasound screening was performed in bilateral common carotid artery (CCA, internal carotid artery (ICA, external carotid artery (ECA, vertebral artery (VA, subclavian artery (SCA and innominate artery of the population. The intima-media thickness (IMT, atherosclerotic plaque formation and its location and size, vascular stenosis or occlusion, and flow spectrum were detected. The results and features of carotid ultrasound screening were analyzed and compared among different gender and age groups.  Results 1 The detection rate of carotid atherosclerosis was 71.55% (684/956, and the detection rate in males was significantly higher than that in females (79.08% vs 65.87%; χ2 = 20.067, P = 0.000. 2 Among the population with carotid atherosclerosis, the most common manifestation was the formation of atherosclerotic plaques (81.58%, 558/684, secondly intima-media thickening (13.01%, 89/684, followed by moderate to severe stenosis or occlusion (5.41%, 37/684. The proportion of intima-media thickening in males was lower than that in females (7.08% vs 18.38%; χ2 = 19.269, P = 0.000. The proportion of carotid atherosclerotic plaque formation in males was higher than that in females (86.46% vs 77.16%; χ2 = 9.824, P = 0.002. The median rating of carotid atherosclerosis was 1.79, with males higher than females [1.98 (0.70, 3.26 vs 1.52 (0.20, 2.84; Z = 2.304, P = 0.042]. The site of plaque formation was most commonly located in carotid bulb (36.61%, secondly SCA (22.18%. Of the type of carotid stenosis, ICA stenosis was detected in 30 cases, VA

  3. High performance carbon nanotube--polymer nanofiber hybrid fabrics.

    Science.gov (United States)

    Yildiz, Ozkan; Stano, Kelly; Faraji, Shaghayegh; Stone, Corinne; Willis, Colin; Zhang, Xiangwu; Jur, Jesse S; Bradford, Philip D

    2015-10-28

    Stable nanoscale hybrid fabrics containing both polymer nanofibers and separate and distinct carbon nanotubes (CNTs) are highly desirable but very challenging to produce. Here, we report the first instance of such a hybrid fabric, which can be easily tailored to contain 0-100% millimeter long CNTs. The novel CNT - polymer hybrid nonwoven fabrics were created by simultaneously electrospinning nanofibers onto aligned CNT sheets which were drawn and collected on a grounded, rotating mandrel. Due to the unique properties of the CNTs, the hybrids show very high tensile strength, very small pore size, high specific surface area and electrical conductivity. In order to further examine the hybrid fabric properties, they were consolidated under pressure, and also calendered at 70 °C. After calendering, the fabric's strength increased by an order of magnitude due to increased interactions and intermingling with the CNTs. The hybrids are highly efficient as aerosol filters; consolidated hybrid fabrics with a thickness of 20 microns and areal density of only 8 g m(-2) exhibited ultra low particulate (ULPA) filter performance. The flexibility of this nanofabrication method allows for the use of many different polymer systems which provides the opportunity for engineering a wide range of nanoscale hybrid materials with desired functionalities.

  4. High frequency conductivity of hot electrons in carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Amekpewu, M., E-mail: mamek219@gmail.com [Department of Applied Physics, University for Development Studies, Navrongo (Ghana); Mensah, S.Y. [Department of Physics, College of Agriculture and Natural Sciences, U.C.C. (Ghana); Musah, R. [Department of Applied Physics, University for Development Studies, Navrongo (Ghana); Mensah, N.G. [Department of Mathematics, College of Agriculture and Natural Sciences, U.C.C. (Ghana); Abukari, S.S.; Dompreh, K.A. [Department of Physics, College of Agriculture and Natural Sciences, U.C.C. (Ghana)

    2016-05-01

    High frequency conductivity of hot electrons in undoped single walled achiral Carbon Nanotubes (CNTs) under the influence of ac–dc driven fields was considered. We investigated semi-classically Boltzmann's transport equation with and without the presence of the hot electrons’ source by deriving the current densities in CNTs. Plots of the normalized current density versus frequency of ac-field revealed an increase in both the minimum and maximum peaks of normalized current density at lower frequencies as a result of a strong injection of hot electrons. The applied ac-field plays a twofold role of suppressing the space-charge instability in CNTs and simultaneously pumping an energy for lower frequency generation and amplification of THz radiations. These have enormous promising applications in very different areas of science and technology.

  5. High frequency conductivity of hot electrons in carbon nanotubes

    Science.gov (United States)

    Amekpewu, M.; Mensah, S. Y.; Musah, R.; Mensah, N. G.; Abukari, S. S.; Dompreh, K. A.

    2016-05-01

    High frequency conductivity of hot electrons in undoped single walled achiral Carbon Nanotubes (CNTs) under the influence of ac-dc driven fields was considered. We investigated semi-classically Boltzmann's transport equation with and without the presence of the hot electrons' source by deriving the current densities in CNTs. Plots of the normalized current density versus frequency of ac-field revealed an increase in both the minimum and maximum peaks of normalized current density at lower frequencies as a result of a strong injection of hot electrons. The applied ac-field plays a twofold role of suppressing the space-charge instability in CNTs and simultaneously pumping an energy for lower frequency generation and amplification of THz radiations. These have enormous promising applications in very different areas of science and technology.

  6. High critical field NbC superconductor on carbon spheres.

    Science.gov (United States)

    Bhattacharjee, Kaustav; Pati, Satya Prakash; Maity, Arjun

    2016-06-01

    Niobium carbide (NbC) nanoparticles embedded on the surface of carbon spheres (CS) were synthesized at 1350 °C by the carbothermal reduction of niobium oxide precursor in flowing argon (Nbc@CS). The morphology, crystal structure, and magnetic properties of the hybrid nanocomposite were investigated by means of electron microscopy, X-ray diffraction and a superconducting quantum interference device. It was found that the NbC@CS nanocomposites exhibit type-II superconductivity with a critical temperature (Tc) of 8-12 K, typical for stoichiometric NbC. The superconducting hysteresis loop reveals several interesting traits, including strong vortex pinning, the presence of asymmetry and a high penetration field. Moreover, the sample shows much improved irreversible (Hirr), lower (Hc1) and upper (Hc2) critical fields. The coherence length (ξ), penetration depth (λ), and Ginzburg-Landau (κ) parameters for the sample were estimated to be 9.78 nm, 33 nm and 3.39, respectively.

  7. Hydrophilic carbon clusters as therapeutic, high capacity antioxidants

    Science.gov (United States)

    Samuel, Errol L. G.; Duong, MyLinh T.; Bitner, Brittany R.; Marcano, Daniela C.; Tour, James M.; Kent, Thomas A.

    2014-01-01

    Oxidative stress reflects an excessive accumulation of reactive oxygen species (ROS) and is a hallmark of several acute and chronic human pathologies. While many antioxidants have been investigated, the majority have demonstrated poor efficacy in clinical trials. Here, we discuss limitations of current antioxidants and describe a new class of nanoparticle antioxidants, poly(ethylene glycol)-functionalized hydrophilic carbon clusters (PEG-HCCs). PEG-HCCs show high capacity to annihilate ROS such as superoxide and hydroxyl radicals, show no reactivity toward nitric oxide, and can be functionalized with targeting moieties without loss of activity. Given these properties, we propose that PEG-HCCs offer an exciting new area of study for treatment of numerous ROS-induced human pathologies. PMID:25175886

  8. Carbon structures and defect planes in diamond at high pressure

    Science.gov (United States)

    Botti, Silvana; Amsler, Maximilian; Flores-Livas, José A.; Ceria, Paul; Goedecker, Stefan; Marques, Miguel A. L.

    2013-07-01

    We performed a systematic structural search of high-pressure carbon allotropes for unit cells containing from 6 to 24 atoms using the minima hopping method. We discovered a series of new structures that are consistently lower in enthalpy than the ones previously reported. Most of these include (5+7)- or (4+8)-membered rings and can therefore be placed in the families proposed by H. Niu [Phys. Rev. Lett.PRLTAO0031-900710.1103/PhysRevLett.108.135501 108, 135501 (2012)]. However, we also found three more families with competitive enthalpies that contain (5+5+8)-membered rings, sp2 motives, or buckled hexagons. These structures are likely to play an important role in dislocation planes and structural defects of diamond and hexagonal diamond.

  9. High conductivity transparent carbon nanotube films deposited from superacid

    Energy Technology Data Exchange (ETDEWEB)

    Hecht, David S; Lee, Roland; Hu Liangbing [Unidym Incorporated, 1244 Reamwood Drive, Sunnyvale, CA 94089 (United States); Heintz, Amy M; Moore, Bryon; Cucksey, Chad; Risser, Steven, E-mail: dhecht@gmail.com [Battelle, 505 King Avenue, Columbus, OH 43201 (United States)

    2011-02-18

    Carbon nanotubes (CNTs) were deposited from a chlorosulfonic superacid solution onto PET substrates by a filtration/transfer method. The sheet resistance and transmission (at 550 nm) of the films were 60 {Omega}/sq and 90.9% respectively, which corresponds to a DC conductivity of 12 825 S cm{sup -1} and a DC/optical conductivity ratio of 64.1. This is the highest DC conductivity reported for CNT thin films to date, and attributed to both the high quality of the CNT material and the exfoliation/doping by the superacid. This work demonstrates that CNT transparent films have not reached the conductivity limit; continued improvements will enable these films to be used as the transparent electrode for applications in solid state lighting, LCD displays, touch panels, and photovoltaics.

  10. High conductivity transparent carbon nanotube films deposited from superacid.

    Science.gov (United States)

    Hecht, David S; Heintz, Amy M; Lee, Roland; Hu, Liangbing; Moore, Bryon; Cucksey, Chad; Risser, Steven

    2011-02-18

    Carbon nanotubes (CNTs) were deposited from a chlorosulfonic superacid solution onto PET substrates by a filtration/transfer method. The sheet resistance and transmission (at 550 nm) of the films were 60 Ω/sq and 90.9% respectively, which corresponds to a DC conductivity of 12,825 S cm(-1) and a DC/optical conductivity ratio of 64.1. This is the highest DC conductivity reported for CNT thin films to date, and attributed to both the high quality of the CNT material and the exfoliation/doping by the superacid. This work demonstrates that CNT transparent films have not reached the conductivity limit; continued improvements will enable these films to be used as the transparent electrode for applications in solid state lighting, LCD displays, touch panels, and photovoltaics.

  11. High dose folic acid supplementation improves arterial endothelial function of coronary patients independent of homocysteine level

    Institute of Scientific and Technical Information of China (English)

    KS Woo; P Chook; M Qiao; AKY Chan; LLT Chan; WWM Chan; DS Celermajer

    2003-01-01

    @@ Background Hyperhomocysteinemia (prevalent in rural northern China)is an emerging risk factor for arterial endothelial dysfunction in CAD, which can be improved with folic acid supplementation. Such homocysteine-lowerying dosage of folio acid ( < 1 mg/d ) can reduce restenosis after PTCA, but not the cardiovascular events.Folic acid has additional vascular protection in antixidation, NO synthase protection, angiogenesis-promotion and cytokines reduction.

  12. High prevalence of peripheral arterial disease in patients with previous cerebrovascular or coronary event

    DEFF Research Database (Denmark)

    Mehlsen, Jesper; Wiinberg, Niels; Joergensen, Bjarne S

    2010-01-01

    The presence of peripheral arterial disease (PAD) in patients with other manifestations of cardiovascular disease identifies a population at increased risk of complications both during acute coronary events and on a long-term basis and possibly a population in whom secondary prevention of cardiov...... of cardiovascular events should be addressed aggressively. The present study was aimed at providing a valid estimate on the prevalence of PAD in patients attending their general practitioner and having previously suffered a cardio- or cerebrovascular event....

  13. Vital Signs – Presión arterial alta (High Blood Pressure)

    Centers for Disease Control (CDC) Podcasts

    2012-10-02

    En los EE. UU. casi un tercio de la población adulta tiene presión arterial alta, el principal factor de riesgo de enfermedades cardiacas y accidentes cerebrovasculares, dos de las principales causas de muerte en el país.  Created: 10/2/2012 by National Center for Chronic Disease Prevention and Health Promotion (NCCDPHP).   Date Released: 10/17/2012.

  14. Angioplasty of symptomatic high-grade internal carotid artery stenosis with intraluminal thrombus: therapeutic approach

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez, A.; Mayol, A. [Seccion de Neurorradiologia Intervencionista, Servicio de Radiologia, Hospital Universitario Virgen del Rocio, Avenida Manuel Siurot s/n, Avenida Manuel Siurot s/n, 41013, Sevilla (Spain); Gil-Peralta, A.; Gonzalez-Marcos, J.R. [Servicio de Neurologia, Hospital Universitario Virgen del Rocio, Avenida Manuel Siurot s/n, 41013, Sevilla (Spain); Boza, F. [Servicio de Neurofisiologia, Hospital Universitario Virgen del Rocio, Avenida Manuel Siurot s/n, 41013, Sevilla (Spain); Ruano, J. [Unidad de Cuidados Intensivos, Hospital Universitario Virgen del Rocio, Avenida Manuel Siurot s/n, 41013, Sevilla (Spain)

    2004-04-01

    Intraluminal thrombus in the internal carotid artery (ICA) is usually found in patients with severe atheromatous stenosis. Having reviewed 300 carotid angioplasties for symptomatic >70% ICA stenosis, we found three patients (1%) with intraluminal thrombus. Conservative treatment with anticoagulants and double antiplatelet coverage can result in lysis of the thrombus without severe risks. Percutaneous transluminal angioplasty and stenting, preferably with distal protection, can be an excellent alternative to carotid endarterectomy. (orig.)

  15. Renal Arteries: Isotropic, High-Spatial-Resolution, Unenhanced MR Angiography with Three-dimensional Radial Phase Contrast1

    Science.gov (United States)

    Lum, Darren P.; Johnson, Kevin M.; Landgraf, Benjamin R.; Bley, Thorsten A.; Reeder, Scott B.; Schiebler, Mark L.; Grist, Thomas M.; Wieben, Oliver

    2011-01-01

    Purpose: To prospectively compare a new three-dimensional (3D) radial phase-contrast magnetic resonance (MR) angiographic method with contrast material–enhanced MR angiography for anatomic assessment of the renal arteries. Materials and Methods: An institutional review board approved this prospective HIPAA-compliant study. Informed consent was obtained. Twenty-seven subjects (mean age, 52.6 years ± 20.5 [standard deviation]) were imaged with respiratory-gated phase-contrast vastly undersampled isotropic projection reconstruction (VIPR) prior to contrast-enhanced MR angiographic acquisition with a 3.0-T clinical system. The imaging duration for phase-contrast VIPR was 10 minutes and provided magnitude and complex difference (“angiographic”) images with 3D volumetric (320 mm) coverage and isotropic high spatial resolution (1.25 mm3). Quantitative analysis consisted of comparing vessel diameters between the two techniques. Qualitative assessment included evaluation of the phase-contrast VIPR and contrast-enhanced MR angiographic techniques for artifacts, noise, and image quality. Bland-Altman analysis was used for comparison of quantitative measurements, and the Wilcoxon signed rank test was used for comparison of qualitative scores. Results: Phase-contrast VIPR images were successfully acquired in all subjects. The vessel diameters measured with phase-contrast VIPR were slightly greater than those measured with contrast-enhanced MR angiography (mean bias = 0.09 mm). Differences in mean artifact, quality scores for the proximal renal arteries, and overall image quality scores between phase-contrast VIPR and contrast-enhanced MR angiographic techniques were not statistically significant (P = .31 and .29, .27 and .39, and .43 and .69 for readers 1 and 2, respectively). The quality scores for the segmental renal arteries were higher for phase-contrast VIPR than for contrast-enhanced MR angiography (P contrast-enhanced MR angiography and were statistically

  16. Cerebral artery alpha-1 AR subtypes: high altitude long-term acclimatization responses.

    Directory of Open Access Journals (Sweden)

    Ravi Goyal

    Full Text Available In response to hypoxia and other stress, the sympathetic (adrenergic nervous system regulates arterial contractility and blood flow, partly through differential activities of the alpha1 (α1 - adrenergic receptor (AR subtypes (α1A-, α1B-, and α1D-AR. Thus, we tested the hypothesis that with acclimatization to long-term hypoxia (LTH, contractility of middle cerebral arteries (MCA is regulated by changes in expression and activation of the specific α1-AR subtypes. We conducted experiments in MCA from adult normoxic sheep maintained near sea level (300 m and those exposed to LTH (110 days at 3801 m. Following acclimatization to LTH, ovine MCA showed a 20% reduction (n = 5; P<0.05 in the maximum tension achieved by 10-5 M phenylephrine (PHE. LTH-acclimatized cerebral arteries also demonstrated a statistically significant (P<0.05 inhibition of PHE-induced contractility in the presence of specific α1-AR subtype antagonists. Importantly, compared to normoxic vessels, there was significantly greater (P<0.05 α1B-AR subtype mRNA and protein levels in LTH acclimatized MCA. Also, our results demonstrate that extracellular regulated kinase 1 and 2 (ERK1/2-mediated negative feedback regulation of PHE-induced contractility is modulated by α1B-AR subtype. Overall, in ovine MCA, LTH produces profound effects on α1-AR subtype expression and function.

  17. Kinematics and chemistry of faint high latitude dwarf carbon stars

    Science.gov (United States)

    Yoon, Jinmi; Beers, Timothy C.; Dietz, Sarah; Lee, Young Sun; Placco, Vinicius M.

    2017-01-01

    The diffuse halo system of the Milky Way is complex, and has been shown to comprise at least two main components: a near-zero net rotation inner-halo and a more rapidly rotating outer-halo component. Studies of the ancient, very metal-poor stars in the Galactic halo system are crucial for understanding its early formation history. The so-called carbon-enhanced metal-poor (CEMP) stars are an important subset of the stars in the halo system, which exhibit distinctive kinematic and chemical signatures that can be used to constrain the star-formation histories and assembly of the various Galactic components.We have examined the sample of main-sequence dwarf and other faint high Galactic latitude carbon-enhanced stars from the Sloan Digital Sky Survey studied by Green (2013). As noted by Green, many of these starsexhibit high proper motions, which have been later claimed to be related to possible binary ejection models Plant et al. (2016). By use of the CEMP sub-classification approach of Yoon et al. (2016), we investigate whether the kinematics of these stars might instead result from their membership in the inner/outer halo populations of the Galaxy.ReferencesGreen, P. 2013, ApJ, 765, 12Plant, K. et al. 2016, AAS 227.34115Yoon, J. et al. 2016, ApJ, in pressAcknowledgementThis work was supported in part by the National Science Foundation under Grant No. PHY-1430152 (JINA Center for the Evolution of the Elements).

  18. Atmospheric aerosol brown carbon in the high Himalayas

    Science.gov (United States)

    Kirillova, Elena; Decesari, Stefano; Marinoni, Angela; Bonasoni, Paolo; Vuillermoz, Elisa; Facchini, M. Cristina; Fuzzi, Sandro

    2016-04-01

    Anthropogenic light-absorbing atmospheric aerosol can reach very high concentrations in the planetary boundary layer in South-East Asia ("brown clouds"), affecting atmospheric transparency and generating spatial gradients of temperature over land with a possible impact on atmospheric dynamics and monsoon circulation. Besides black carbon (BC), an important light-absorbing component of anthropogenic aerosols is the organic carbon component known as 'brown carbon' (BrC). In this research, we provided first measurements of atmospheric aerosol BrC in the high Himalayas during different seasons. Aerosol sampling was conducted at the GAW-WMO Global station "Nepal Climate Observatory-Pyramid" (NCO-P) located in the high Khumbu valley at 5079 m a.s.l. in the foothills of Mt. Everest. PM10 aerosol samples were collected from July 2013 to November 2014. The sampling strategy was set up in order to discriminate the daytime valley breeze bringing polluted air masses up to the observatory and free tropospheric air during nighttime. Water-soluble BrC (WS-BrC) and methanol-soluble BrC (MeS-BrC) were extracted and analyzed using a UV/VIS spectrophotometer equipped with a 50 cm liquid waveguide capillary cell. In the polluted air masses, the highest levels of the BrC light absorption coefficient at 365 nm (babs365) were observed during the pre-monsoon season (1.83±1.46 Mm-1 for WS-BrC and 2.86±2.49 Mm-1 for MeS-BrC) and the lowest during the monsoon season (0.21±0.22 Mm-1 for WS-BrC and 0.32±0.29 Mm-1 for MeS-BrC). The pre-monsoon season is the most frequently influenced by a strong atmospheric brown cloud (ABC) transport to NCO-P due to increased convection and mixing layer height over South Asia combined with the highest up-valley wind speed and the increase of the emissions from open fires due to the agricultural practice along the Himalayas foothills and the Indo-Gangetic Plain. In contrast, the monsoon season is characterized by a weakened valley wind regime and an

  19. Increased level of glycated hemoglobin portends high risk of coronary artery stenosis

    Institute of Scientific and Technical Information of China (English)

    ZENG FAN-fang; WANG Li-li; LONG Juan; YI Wen-ya; LUO Ying

    2016-01-01

    Background Increased level of glycated hemoglobin (HbA1c) is associated with higher incidence of coronary artery disease (CAD) in the diabetics.However,the relationship between HbAlc and the risk of coronary artery stenosis in the non-diabetics is controversial.Methods A retrospective research was conducted on 338 enrolled participants who have undergone 2 times of coronary angiographic examination within the past year.Clinical and laboratory variables at the initial and the second time of admission were collected.According to the initial median HbA1c level,all participants were divided into two groups named lower and higher groups.The relationship between HbA1c level and the risk of coronary artery stenosis over time was evaluated.Results The initial values of HbA1c in lower and upper groups were 5.78 ± 0.35% and 6.21 ± 0.32% (P < 0.05).As compared to the lower group,the percentages of male and smoking participants,and the serum level of CRP were significantly higher in the higher group (P < 0.05).Other traditional risk factors were comparable between the two groups.There were 54.2% and 55.2% participants with single vessel stenosis,and 45.8% and 44.8% with multiple vessel stenoses,respectively in the two groups without significant difference.The second time of admission,were 308.5± 25.4 days (lower group) and 300.7 ± 30.1 days (higher group) from the initial admission.Although no significant changes of HbA1c level were observed when compared to initial,HbA1c level in the higher group was still significantly higher in comparison to the lower group (6.24 ± 0.39% vs.5.80 ± 0.36%,P =0.008).The percentage of new coronary artery stenosis (≥ 50% stenosis) was higher in the higher group than that in the lower group (41.7% vs.32.3%,P < 0.001).Multivariate regression analyses suggested that HbAlc remained independent factor associated with coronary artery stenoses after extensive adjustment for risk factors.Conclusion In the nondiabetics

  20. Effect of high-intensity statin therapy on atherosclerosis in non-infarct-related coronary arteries (IBIS-4)

    DEFF Research Database (Denmark)

    Räber, Lorenz; Taniwaki, Masanori; Zaugg, Serge

    2015-01-01

    AIM: The effect of long-term high-intensity statin therapy on coronary atherosclerosis among patients with acute ST-segment elevation myocardial infarction (STEMI) is unknown. The aim of this study was to quantify the impact of high-intensity statin therapy on plaque burden, composition, and phen......AIM: The effect of long-term high-intensity statin therapy on coronary atherosclerosis among patients with acute ST-segment elevation myocardial infarction (STEMI) is unknown. The aim of this study was to quantify the impact of high-intensity statin therapy on plaque burden, composition......, and phenotype in non-infarct-related arteries of STEMI patients undergoing primary percutaneous coronary intervention (PCI). METHODS AND RESULTS: Between September 2009 and January 2011, 103 STEMI patients underwent intravascular ultrasonography (IVUS) and radiofrequency ultrasonography (RF-IVUS) of the two non......, P = 0.15). CONCLUSION: High-intensity rosuvastatin therapy over 13 months is associated with regression of coronary atherosclerosis in non-infarct-related arteries without changes in RF-IVUS defined necrotic core or plaque phenotype among STEMI patients....

  1. Effect of cinnamon on gastric emptying, arterial stiffness, postprandial lipemia, glycemia, and appetite responses to high-fat breakfast

    LENUS (Irish Health Repository)

    Markey, Oonagh

    2011-09-07

    Abstract Background Cinnamon has been shown to delay gastric emptying of a high-carbohydrate meal and reduce postprandial glycemia in healthy adults. However, it is dietary fat which is implicated in the etiology and is associated with obesity, type 2 diabetes and cardiovascular disease. We aimed to determine the effect of 3 g cinnamon (Cinnamomum zeylanicum) on GE, postprandial lipemic and glycemic responses, oxidative stress, arterial stiffness, as well as appetite sensations and subsequent food intake following a high-fat meal. Methods A single-blind randomized crossover study assessed nine healthy, young subjects. GE rate of a high-fat meal supplemented with 3 g cinnamon or placebo was determined using the 13C octanoic acid breath test. Breath, blood samples and subjective appetite ratings were collected in the fasted and during the 360 min postprandial period, followed by an ad libitum buffet meal. Gastric emptying and 1-day fatty acid intake relationships were also examined. Results Cinnamon did not change gastric emptying parameters, postprandial triacylglycerol or glucose concentrations, oxidative stress, arterial function or appetite (p < 0.05). Strong relationships were evident (p < 0.05) between GE Thalf and 1-day palmitoleic acid (r = -0.78), eiconsenoic acid (r = -0.84) and total omega-3 intake (r = -0.72). The ingestion of 3 g cinnamon had no effect on GE, arterial stiffness and oxidative stress following a HF meal. Conclusions 3 g cinnamon did not alter the postprandial response to a high-fat test meal. We find no evidence to support the use of 3 g cinnamon supplementation for the prevention or treatment of metabolic disease. Dietary fatty acid intake requires consideration in future gastrointestinal studies. Trial registration Trial registration number: at http:\\/\\/www.clinicaltrial.gov: NCT01350284

  2. Effect of cinnamon on gastric emptying, arterial stiffness, postprandial lipemia, glycemia, and appetite responses to high-fat breakfast

    Directory of Open Access Journals (Sweden)

    Trinick Tom R

    2011-09-01

    Full Text Available Abstract Background Cinnamon has been shown to delay gastric emptying of a high-carbohydrate meal and reduce postprandial glycemia in healthy adults. However, it is dietary fat which is implicated in the etiology and is associated with obesity, type 2 diabetes and cardiovascular disease. We aimed to determine the effect of 3 g cinnamon (Cinnamomum zeylanicum on GE, postprandial lipemic and glycemic responses, oxidative stress, arterial stiffness, as well as appetite sensations and subsequent food intake following a high-fat meal. Methods A single-blind randomized crossover study assessed nine healthy, young subjects. GE rate of a high-fat meal supplemented with 3 g cinnamon or placebo was determined using the 13C octanoic acid breath test. Breath, blood samples and subjective appetite ratings were collected in the fasted and during the 360 min postprandial period, followed by an ad libitum buffet meal. Gastric emptying and 1-day fatty acid intake relationships were also examined. Results Cinnamon did not change gastric emptying parameters, postprandial triacylglycerol or glucose concentrations, oxidative stress, arterial function or appetite (p half and 1-day palmitoleic acid (r = -0.78, eiconsenoic acid (r = -0.84 and total omega-3 intake (r = -0.72. The ingestion of 3 g cinnamon had no effect on GE, arterial stiffness and oxidative stress following a HF meal. Conclusions 3 g cinnamon did not alter the postprandial response to a high-fat test meal. We find no evidence to support the use of 3 g cinnamon supplementation for the prevention or treatment of metabolic disease. Dietary fatty acid intake requires consideration in future gastrointestinal studies. Trial registration Trial registration number: at http://www.clinicaltrial.gov: NCT01350284

  3. INFLUENCE OF HEAT TREATMENT ON OXIDATION PROPERTIES OF C/C COMPOSITES FABRICATED BY HIGH PRESSURE IMPREGNATION CARBONIZATION

    Institute of Scientific and Technical Information of China (English)

    Q.Chen; H.J.Li; A.J.Li; H.M.Han; K.Z.Li

    2004-01-01

    Felt base carbon/carbon composites fabricated by super-high pressure impregnation carbonization process (SPIC) were heat treated at high temperature 2773K. The oxidation properties of felt base carbon/carbon composites were investigated at different temperatures (773-1173K), and the microstructures of carbon/carbon composites were studied by SEM and X-ray diffraction. The experimental results showed that the interlaminar distance of (002) plane (doo2) deceased while the microcrystalline stack height (Lc) increased. The oxidation rate of felt base carbon/carbon composites was invariable at certain temperatures. The oxidation mechanism of carbon/carbon composites changed remarkably at the oxidation temperature 973K. At the initial oxidation stage of carbon/carbon composites, carbon matrix was oxidized much more rapidly than carbon felt.

  4. High Performance Shape Memory Epoxy/Carbon Nanotube Nanocomposites.

    Science.gov (United States)

    Liu, Yayun; Zhao, Jun; Zhao, Lingyu; Li, Weiwei; Zhang, Hui; Yu, Xiang; Zhang, Zhong

    2016-01-13

    A series of shape memory nanocomposites based on diglycidyl ether of bisphenol A (DGEBA) E51/methylhexahydrophthalic anhydride (MHHPA)/multiwalled carbon nanotube (MWCNT) with various stoichiometric ratios (rs) of DGEBA/MHHPA from 0.5 to 1.2 and filler contents of 0.25 and 0.75 wt % are fabricated. Their morphology, curing kinetics, phase transition, mechanical properties, thermal conduction, and shape memory behaviors are systematically investigated. The prepared materials show a wide range of glass transition temperatures (Tg) of ca. 65-140 °C, high flexural modulus (E) at room temperature up to ca. 3.0 GPa, high maximum stress (σm) up to ca. 30 MPa, high strain at break (εb) above 10%, and a fast recovery of 32 s. The results indicate that a small amount of MWCNT fillers (0.75 wt %) can significantly increase all three key mechanical properties (E, σm, and εb) at temperatures close to Tg, the recovery rate, and the repetition stability of the shape memory cycles. All of these remarkable advantages make the materials good candidates for the applications in aerospace and other important fields.

  5. Highly compressed nanosolution restricted in cylindrical carbon nanospaces

    Science.gov (United States)

    Nishi, Masayasu; Ohkubo, Takahiro; Tsurusaki, Kazuma; Itadani, Atsushi; Ahmmad, Bashir; Urita, Koki; Moriguchi, Isamu; Kittaka, Shigeharu; Kuroda, Yasushige

    2013-02-01

    We shed light on the specific hydration structure around a zinc ion of nanosolution restricted in a cylindrical micropore of single-wall carbon nanotube (SWNT) by comparison with the structure restricted in a cylindrical mesopore of multi-wall carbon nanotube (MWNT) and that of bulk aqueous solution. The average micropore width of open-pore SWNT was 0.87 nm which is equivalent to the size of a hydrated zinc ion having 6-hydrated water molecules. We could impregnate the zinc ions into the micropore of SWNT with negligible amounts of ion-exchanged species on surface functional groups by the appropriate oxidation followed by heat treatment under an inert condition. The results of X-ray absorption fine structure (XAFS) spectra confirmed that the proportion of dissolved species in nanospaces against the total adsorbed amounts of zinc ions on the open-pore SWNT and MWNT were 44 and 61%, respectively, indicating the formation of a dehydrated structure in narrower nanospaces. The structure parameters obtained by the analysis of XAFS spectra also indicate that the dehydrated and highly compressed hydration structure can be stably formed inside the cylindrical micropore of SWNT where the structure is different from that inside the slit-shaped micropore whose pore width is less than 1 nm. Such a unique structure needs not only a narrow micropore geometry which is equivalent to the size of a hydrated ion but also the cylindrical nature of the pore.We shed light on the specific hydration structure around a zinc ion of nanosolution restricted in a cylindrical micropore of single-wall carbon nanotube (SWNT) by comparison with the structure restricted in a cylindrical mesopore of multi-wall carbon nanotube (MWNT) and that of bulk aqueous solution. The average micropore width of open-pore SWNT was 0.87 nm which is equivalent to the size of a hydrated zinc ion having 6-hydrated water molecules. We could impregnate the zinc ions into the micropore of SWNT with negligible amounts of

  6. Long-term use of first-line highly active antiretroviral therapy is not associated with carotid artery stiffness in human immunodeficiency virus-positive patients

    Directory of Open Access Journals (Sweden)

    Haohui Zhu

    2014-09-01

    Full Text Available Objective: To evaluate whether or not highly active antiretroviral therapy is associated with carotid artery stiffness in human immunodeficiency virus-positive patients in Henan Province, China. Method: Fifty human immunodeficiency virus-positive patients with at least a 5-year history of highly active antiretroviral therapy use and 50 human immunodeficiency virus-positive patients without a history of highly active antiretroviral therapy use were enrolled in this study. Carotid artery intima-media thickness and stiffness were determined by quantitative inter-media thickness and quantitative artery stiffness, respectively. Results: No statistically significant difference in carotid artery intima-media thickness and stiffness was observed between groups. A significant association between human immunodeficiency virus infection time and carotid artery stiffness was observed, but no significant association between human immunodeficiency virus infection time and intima-media thickness was found. No significant association between intima-media thickness, stiffness, and CD4+ and CD8+ T-cell counts were observed. Conclusion: The first-line highly active antiretroviral therapy currently used in China is not associated with carotid artery stiffness in human immunodeficiency virus-positive patients with good highly active antiretroviral therapy compliance. Human immunodeficiency virus may play a role in the development of atherosclerosis.

  7. Strength study of carbon dioxide under high pressures

    Science.gov (United States)

    Kaci, L.; Shieh, S. R.; Kiefer, B.

    2011-12-01

    Carbon dioxide (CO2) is one of the greenhouse gases that can be readily found in the Earth's atmosphere and possibly inside the Earth. The strength and elasticity study of carbon dioxide (CO2) under high pressures is important to understand the rheological behavior of CO2 that may be relevant to the CO2 storage issue within the Earth and also the evolution of other planets. Quantitative measurements of the strength of CO2 were achieved in a diamond anvil cell using x-ray diffraction in a radial geometry. CO2 sample was cryogenically loaded into a beryllium gasket and a thin foil of gold about 20 x 20 um2 was placed at the center of the gasket hole to serve as a pressure standard. The x-ray diffraction data were collected at beamline X17C of National Synchrotron Light Source, Brookhaven National Laboratory. We have determined the strength using three different methods. We analyze the peak broadening measurements in the axial direction, peak shifts in radial direction associated with lattice strains theory and also we measured pressure gradient of the CO2 under stress using ruby florescence method. Our results show that the ratios of differential stress to shear modulus are ranging from 0.006(5) to 0.04(18), exhibiting a positive slope within the applied pressure to 12 GPa. The differential stress was calculated as 0.029(3)-0.224(28) GPa, with the inputs of shear module from theoretical calculations. Our differential stress values are close to those of argon data at low pressures. In addition, our results show no pressure gradient of CO2 below 20 GPa. This fact suggests that up to 20GPa the differential stress supported by CO2 is mainly arising from elastic deformation. This is also supported by the linear positive trend of differential strain demonstrating the elastic regime up to 12 GPa.

  8. Quantification of coronary artery stenosis with high-resolution CT in comparison with histopathology in an ex vivo study

    Energy Technology Data Exchange (ETDEWEB)

    Dettmer, Matthias, E-mail: dettmerms@upmc.edu [Department of Pathology and Laboratory Medicine, University of Pittsburgh, S-417 BST 200 Lothrop Street, Pittsburgh, PA 15261 (United States); Glaser-Gallion, Nicola, E-mail: nicola.glaser-gallion@kssg.ch [Institute of Radiology, Kantonsspital St. Gallen, Rorschacherstrasse 95, 9007 St. Gallen (Switzerland); Stolzmann, Paul, E-mail: paul.stolzmann@usz.ch [Institute of Diagnostic and Interventional Radiology, University Hospital Zurich, Rämistrasse 100, 8091 Zurich (Switzerland); Glaser-Gallion, Florian, E-mail: florian.glaser-gallion@kssg.ch [Institute of Radiology, Kantonsspital St. Gallen, Rorschacherstrasse 95, 9007 St. Gallen (Switzerland); Fornaro, Juergen, E-mail: juergen.fornaro@kssg.ch [Institute of Radiology, Kantonsspital St. Gallen, Rorschacherstrasse 95, 9007 St. Gallen (Switzerland); Feuchtner, Gudrun, E-mail: Gudrun.Feuchtner@i-med.ac.at [Department of Radiology II, Medical University Innsbruck, Anichstr. 35, 6020 Innsbruck (Austria); Jochum, Wolfram, E-mail: wolfram.jochum@kssg.ch [Institute of Pathology, Kantonsspital St. Gallen, Rorschacherstrasse 95, 9007 St. Gallen (Switzerland); Alkadhi, Hatem, E-mail: hatem.alkadhi@usz.ch [Institute of Diagnostic and Interventional Radiology, University Hospital Zurich, Rämistrasse 100, 8091 Zurich (Switzerland); Wildermuth, Simon, E-mail: simon.wildermuth@kssg.ch [Institute of Radiology, Kantonsspital St. Gallen, Rorschacherstrasse 95, 9007 St. Gallen (Switzerland); Leschka, Sebastian, E-mail: sebastian.leschka@kssg.ch [Institute of Radiology, Kantonsspital St. Gallen, Rorschacherstrasse 95, 9007 St. Gallen (Switzerland)

    2013-02-15

    Purpose: To investigate the ex vivo performance of high-resolution computed tomography (CT) for quantitative assessment of percentage diameter stenosis in coronary arteries compared to histopathology. Materials and methods: High-resolution CT was performed in 26 human heart specimens after the injection of iodinated contrast media into the coronary arteries. Coronary artery plaques were visually identified on CT images and the grade of stenosis for each plaque was measured with electronic calipers. All coronary plaques were characterized by histopathology according to the Stary classification, and the percentage of stenosis was measured. Results: CT depicted 84% (274/326) of all coronary plaques identified by histology. Missed plaques by CT were of Stary type I (n = 31), type II (n = 16), and type III (n = 5). The stenosis degree significantly correlated between CT and histology (r = 0.81, p < 0.001). CT systematically overestimated the stenosis of calcified plaques (mean difference - 11.0 ± 9.5%, p < 0.01) and systematically underestimated the stenosis of non-calcified plaques (mean difference −6.8 ± 10.4%, p < 0.05), while there was no significant difference for mixed-type plaques (mean difference −0.4 ± 11.7%, p = 0.85). There was a significant underestimation of stenosis degree as measured by CT for Stary II plaques (mean difference −14 ± 9%, p < 0.01) and a significant overestimation for Stary VII plaques (mean difference 9 ± 10%, p < 0.05), but there was no significant difference in stenosis degree between both modalities for other plaque types. Conclusions: High-resolution CT reliably depicts advanced stage coronary plaques with an overall good correlation of stenosis degree compared to histology, however, the degree of stenosis is systematically overestimated in calcified and underestimated in non-calcified plaques.

  9. High performance aqueous supercapacitor based on highly nitrogen-doped carbon nanospheres with unimodal mesoporosity

    Science.gov (United States)

    Sun, Fei; Gao, Jihui; Pi, Xinxin; Wang, Lijie; Yang, Yuqi; Qu, Zhibin; Wu, Shaohua

    2017-01-01

    Herein, we report a high performance aqueous supercapacitor which is made of highly nitrogen-doped carbon nanospheres (NRMCs) with unimodal mesoporosity. An aerosol-assisted spraying process is employed to obtain the nano-sized NRMC particles possessing large surface areas, high pore volumes and ultra-high N doping levels (14.51%-20.55%). Evaluated as supercapacitor electrode, the optimized NRMC exhibits excellent performance for aqueous electrical double layer capacitors with high material-level specific capacitance (432 F g-1 at 1 A g-1), excellent rate performance (205 F g-1 at a high current density of 100 A g-1) and high cycling stability. The constructed symmetric supercapacitor delivers high energy densities of 9.2 Wh kg-1 and 4 Wh kg-1 at power densities of 0.11 kW kg-1 and 23.24 kW kg-1, respectively. Moreover, the effect of N specie distribution on the rate performance is also demonstrated, which highlights the important role of tuning the N doping patterns on enhancing the supercapacitive performances of carbon materials.

  10. Thermodynamic diagrams for high temperature plasmas of air, air-carbon, carbon-hydrogen mixtures, and argon

    CERN Document Server

    Kroepelin, H; Hoffmann, K-U

    2013-01-01

    Thermodynamic Diagrams for High Temperature Plasmas of Air, Air-Carbon, Carbon-Hydrogen Mixtures, and Argon provides information relating to the properties of equilibrium gas plasmas formed from hydrocarbons, from air without argon, from pure argon, and from mixtures of air and carbon at various compositions, temperatures and pressures. The data are presented in graphical rather than tabular form to provide a clearer picture of the plasma processes investigated. This book is composed of four chapters, and begins with the introduction to the characteristics of plasmas, with emphasis on their th

  11. 3D hybrid-porous carbon derived from carbonization of metal organic frameworks for high performance supercapacitors

    Science.gov (United States)

    Bao, Weizhai; Mondal, Anjon Kumar; Xu, Jing; Wang, Chengyin; Su, Dawei; Wang, Guoxiu

    2016-09-01

    We report a rational design and synthesis of 3D hybrid-porous carbon with a hierarchical pore architecture for high performance supercapacitors. It contains micropores (<2 nm diameter) and mesopores (2-4 nm), derived from carbonization of unique porous metal organic frameworks (MOFs). Owning to the synergistic effect of micropores and mesopores, the hybrid-porous carbon has exceptionally high ion-accessible surface area and low ion diffusion resistance, which is desired for supercapacitor applications. When applied as electrode materials in supercapacitors, 3D hybrid-porous carbon demonstrates a specific capacitance of 332 F g-1 at a constant charge/discharge current of 500 mA g-1. The supercapacitors can endure more than 10,000 cycles without degradation of capacitance.

  12. Determination of the luminal diameter of the radial artery in man by high frequency ultrasound

    DEFF Research Database (Denmark)

    Nielsen, T H; Iversen, Helle Klingenberg; Tfelt-Hansen, P

    1990-01-01

    measurements. By comparing the diameter of the reference object either filled with water or blood at 37 degrees C, the ultrasound velocity in human blood at 37 degrees C was calculated to be 1605 m/s. The intraobserver repeatability coefficients of in-vivo measurements of the radial artery in man were...... in the same range, whether measurements were repeated after 30 min (14%) or from day to day (12%). The interobserver repeatability coefficient was acceptable (15%) when the site of measurements was marked, whereas measurements without a mark resulted in a repeatability coefficient of 24%. The intravenous...

  13. High normal thyroid-stimulating hormone is associated with arterial stiffness in healthy postmenopausal women.

    Science.gov (United States)

    Lambrinoudaki, Irene; Armeni, Eleni; Rizos, Demetrios; Georgiopoulos, Georgios; Kazani, Maria; Alexandrou, Andreas; Deligeoroglou, Efthymios; Livada, Alexandra; Psychas, Charalampos; Creatsa, Maria; Bouboulis, George; Alevizaki, Maria; Stamatelopoulos, Kimon

    2012-03-01

    Apart from the effects of a dysfunctional thyroid gland on the cardiovascular system, thyroid function within the reference range may have an impact on the vasculature. The present study aimed to evaluate the association between thyroid function and markers of arterial structure and function in euthyroid postmenopausal women. The present cross-sectional study recruited 106 healthy postmenopausal women with a mean age of 55.0 years and thyroid-stimulating hormone (TSH) levels within the laboratory reference range (0.4-4.5 μIU/ml). Anthropometric and biochemical measures as well as blood pressure were determined in each individual. Vascular structure and function were assessed by intima-media thickness, pulse wave velocity (PWV), augmentation index and flow-mediated dilation, respectively. We evaluated the associations between arterial markers and serum TSH, free triiodothyronine, free thyroxin, as well as serum thyroid peroxidase and thyroglobulin autoantibodies. Mean levels of PWV increased linearly across increasing TSH quartiles (P value = 0.014). Individuals with serum TSH greater than 2.5 μIU/ml had significantly higher values of PWV when compared with individuals with TSH levels below 2.5 μIU/ml (9.68 ± 1.97 vs. 8.54 ± 1.83 m/s; P = 0.030). In multivariate analysis, age, insulin resistance and TSH above 2.5 μIU/ml were the only significant predictors of PWV (TSH, β-coefficient = 0.222; P = 0.014). No associations were found between the remaining markers and levels of thyroid hormones, whereas thyroid antibodies were not associated with any of the arterial markers. Women with TSH levels in the upper reference range have increased arterial stiffness compared to women with lower TSH. The upper limit of normal TSH in postmenopausal women may need re-evaluation with respect to the effects on the vasculature.

  14. Lp-PLA₂- a novel risk factor for high-risk coronary and carotid artery disease.

    Science.gov (United States)

    Epps, K C; Wilensky, R L

    2011-01-01

    Lipoprotein-associated phospholipase A2 (Lp-PLA₂) is at the crossroads of lipid metabolism and the inflammatory response. It is produced by inflammatory cells, bound to LDL and other lipoproteins, and once in the arterial wall facilitates hydrolysis of phospholipids. Elevated serum levels of Lp-PLA₂ have been associated with increased cardiovascular risk in healthy populations and in patients with known vascular disease. Here, we review the role of Lp-PLA₂ in the development of atherosclerosis and progression to unstable disease, the utility of Lp-PLA₂ as a risk predictor for coronary and carotid events and the potential clinical benefit of pharmacologic inhibition of Lp-PLA₂.

  15. Highly sensitive thermoluminescent carbon doped nanoporous aluminium oxide detectors.

    Science.gov (United States)

    de Azevedo, W M; de Oliveira, G B; da Silva, E F; Khoury, H J; Oliveira de Jesus, E F

    2006-01-01

    In this work we present the synthesis, characterisation and the thermoluminescence (TL) response of nanoporous carbon doped aluminium oxide Al2O3:C produced by anodic oxidation of aluminium in organic and inorganic solvents. The X-ray and scanning electron microscopy (SEM) measurements reveal that the synthesised samples are amorphous and present highly ordered structures with uniform pore distribution with diameter of the order 50 nm. The photoluminescence and spectroscopic analysis in the visible and infrared regions show that the luminescence properties presented by the samples prepared in organic acid are due to carboxylate species, incorporated in anodic alumina films during the synthesis process. After an annealing treatment, part of the incorporated species decomposes and is incorporated into the structure of the aluminium oxide yielding a highly thermoluminescent detector (TL) . The results for X-ray irradiation in the range from 21 to 80 keV indicate a linear TL response with the dose in the range from 5 mGy to 1 Gy, suggesting that nanoporous aluminium oxide produced in the present route of synthesis is a suitable detector for radiation measurements.

  16. Genetics Home Reference: pulmonary arterial hypertension

    Science.gov (United States)

    ... Home Health Conditions pulmonary arterial hypertension pulmonary arterial hypertension Enable Javascript to view the expand/collapse boxes. ... PDF Open All Close All Description Pulmonary arterial hypertension is a progressive disorder characterized by abnormally high ...

  17. Synthesis of High-Surface-Area Nitrogen-Doped Porous Carbon Microflowers and Their Efficient Carbon Dioxide Capture Performance.

    Science.gov (United States)

    Li, Yao; Cao, Minhua

    2015-07-01

    Sustainable carbon materials have received particular attention in CO2 capture and storage owing to their abundant pore structures and controllable pore parameters. Here, we report high-surface-area hierarchically porous N-doped carbon microflowers, which were assembled from porous nanosheets by a three-step route: soft-template-assisted self-assembly, thermal decomposition, and KOH activation. The hydrazine hydrate used in our experiment serves as not only a nitrogen source, but also a structure-directing agent. The activation process was carried out under low (KOH/carbon=2), mild (KOH/carbon=4) and severe (KOH/carbon=6) activation conditions. The mild activated N-doped carbon microflowers (A-NCF-4) have a hierarchically porous structure, high specific surface area (2309 m(2)  g(-1)), desirable micropore size below 1 nm, and importantly large micropore volume (0.95 cm(3)  g(-1)). The remarkably high CO2 adsorption capacities of 6.52 and 19.32 mmol g(-1) were achieved with this sample at 0 °C (273 K) and two pressures, 1 bar and 20 bar, respectively. Furthermore, this sample also exhibits excellent stability during cyclic operations and good separation selectivity for CO2 over N2.

  18. High biolability of ancient permafrost carbon upon thaw

    NARCIS (Netherlands)

    Vonk, Jorien E.; Mann, Paul J.; Davydov, Sergey; Davydova, Anna; Spencer, Robert G. M.; Schade, John; Sobczak, William V.; Zimov, Nikita; Zimov, Sergei; Bulygina, Ekaterina; Eglinton, Timothy I.; Holmes, Robert M.

    2013-01-01

    Ongoing climate warming in the Arctic will thaw permafrost and remobilize substantial terrestrial organic carbon (OC) pools. Around a quarter of northern permafrost OC resides in Siberian Yedoma deposits, the oldest form of permafrost carbon. However, our understanding of the degradation and fate of

  19. High biolability of ancient permafrost carbon upon thaw

    NARCIS (Netherlands)

    Vonk, Jorien E.; Mann, Paul J.; Davydov, Sergey; Davydova, Anna; Spencer, Robert G. M.; Schade, John; Sobczak, William V.; Zimov, Nikita; Zimov, Sergei; Bulygina, Ekaterina; Eglinton, Timothy I.; Holmes, Robert M.

    2013-01-01

    Ongoing climate warming in the Arctic will thaw permafrost and remobilize substantial terrestrial organic carbon (OC) pools. Around a quarter of northern permafrost OC resides in Siberian Yedoma deposits, the oldest form of permafrost carbon. However, our understanding of the degradation and fate of

  20. High Speed Rail: Implications for carbon emissions and biodiversity

    DEFF Research Database (Denmark)

    Cornet, Yannick; Dudley, Geoffrey; Banister, David

    2017-01-01

    Rail has traditionally been seen as ‘good’ for the environment, as it is fast and efficient with a low carbon footprint. With respect to HS2 in the UK, new environmental debates have arisen over the competing global objectives of reducing the carbon footprint of HSR and the need to maintain and e...... levels of carbon emissions and biodiversity loss.......Rail has traditionally been seen as ‘good’ for the environment, as it is fast and efficient with a low carbon footprint. With respect to HS2 in the UK, new environmental debates have arisen over the competing global objectives of reducing the carbon footprint of HSR and the need to maintain...

  1. Evaluation of high-pitch dual-source CT angiography for evaluation of coronary and carotid-cerebrovascular arteries

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Kai [Department of Radiology, Xuanwu Hospital, Capital Medical University, Beijing 100053 (China); Li, Kuncheng, E-mail: cjr.likuncheng@vip.163.com [Department of Radiology, Xuanwu Hospital, Capital Medical University, Beijing 100053 (China); Han, Ruijuan [Department of Cardiology, Chaoyang Hospital, Capital Medical University, Beijing 100020 (China); Li, Wenhuan; Chen, Nan; Yang, Qi; Du, Xiangying; Wang, Chen [Department of Radiology, Xuanwu Hospital, Capital Medical University, Beijing 100053 (China); Liu, Guorong; Li, Yuechun [Department of Neurology Baotou Central Hospital, Inner Mongolia, Baotou 014040 (China); Zhou, Maorong [Department of Radiology, Baotou Central Hospital, Inner Mongolia, Baotou 014040 (China); Li, Ligang; Heidrun, Endt [CT BM Clinic Marketing, Siemens Healthcare, Beijing 100102 (China)

    2015-03-15

    Objectives: To explore the feasibility and diagnostic accuracy of a combined one-step high-pitch dual-source computed tomography angiography (CTA) technique for evaluation of coronary and carotid-cerebrovascular arteries. Materials and methods: 85 symptomatic patients suspected of coronary artery and cerebrovascular disease referred for simultaneous coronary and carotid-cerebrovascular CTA were included. Additional invasive angiography of the coronary and cerebral arteries was performed within 30 days in 23 and 13 patients, respectively. The objective parameters of image quality, the mean CT attenuations, image noise, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR) were evaluated. The subjective image quality of vessels was also assessed by 2 independent radiologists blinded to the patients’ medical history and scan protocols. The diagnostic performance of CTA including sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) for the detection or exclusion of significant artery stenosis was calculated using the chi-squared test of contingency and correlated with the results of invasive angiography representing the standard of reference. Results: Image quality was rated excellent (score 1) in 95.3% (1074/1127), good (score 2) in 3.3% (37/1127), adequate (score 3) in 1.0% (11/1127), and non-diagnostic (score 4) in 0.4% (5/1127) of coronary segments. Image quality of carotid and cerebral vessels was rated mostly excellent (score 1, 95.12% [78/82]; score 2, 3.66% [3/82]; score 3, 1.22% [1/82]). The sensitivity, specificity, PPV and NPV for the detection of coronary stenosis were 92.2% (81.1–97.7%), 95.2% (91.7–97.5%), 79.6% (67.1–89.1%) and 98.3% (95.8–99.5%), respectively. For the detection of carotid and cerebral artery stenosis, CTA demonstrated a sensitivity of 92.8% (80.5–98.4%), a specificity of 93.5% (88.3–96.8%), a PPV of 79.6% (65.6–89.7%) and a NPV of 97.9% (94.1–99.5%). The effective

  2. High speed railway promoting development of low-carbon economy in China%High speed railway promoting development of low-carbon economy in China

    Institute of Scientific and Technical Information of China (English)

    Zhou Xinjun

    2011-01-01

    Low-carbon Economy is a kind of economic developing mode which takes low energy consumption, low pollution and low discharge as its foundation. It is another important revolution of the human society after the agriculture civilization and industry civilization. It deals with various fields including low-carbon energy, low-carbon agriculture, lowcarbon industry, low-carbon transportation and low-carbon life, etc. Among those, low-carbon transportation is one of the important contents. Since high speed railway uses electricity as driving force, it runs without discharging waste gas, and it is a kind of clean and green transportation with little dust and smoke black. Therefore, the study of the relationship between the high speed railway and low-carbon economy is becoming one of the important frontier problems that confronting the theoretic circle. With demonstration analysis and comparative analysis, this paper discusses the comparative advantages of high speed railway in terms of energy saving and environment protection, treatment of sound pollution, land saving and reduction of external cost ( mainly pollution treatment cost), etc. compared with the other transportation modes and ordinary railway. Taking Beijing~Tianjin Intercity Railway as an example, the paper further demonstrates the distinctive advantages in respect of energy conservation and emission reduction. Besides, the paper also predicates the low-carbon effects after several high speed railways is put into operation in a few years. It is concluded that the development of high speed railways will meet the need of low-carbon economy and is significant for sustainable and steady development of economy and society.

  3. Converting biowaste corncob residue into high value added porous carbon for supercapacitor electrodes.

    Science.gov (United States)

    Qu, Wen-Hui; Xu, Yuan-Yuan; Lu, An-Hui; Zhang, Xiang-Qian; Li, Wen-Cui

    2015-08-01

    In this report, corncob residue, the main by-product in the furfural industry, is used as a precursor to prepare porous carbon by a simple and direct thermal treatment: one-step activation without pre-carbonization. As a consequence, the corncob residue derived porous carbon achieves a high surface area of 1210 m(2) g(-1) after ash-removal. The carbon material has the advantages of low cost and low environmental impact, with a superior electrochemical performance compared to those polymer-based synthetic carbons as electrode material for a supercapacitor. The carbon electrode exhibits a high capacitance of 314 F g(-1) in 6M KOH electrolyte. The corresponding sample also shows a superb cycling stability. Almost no capacitance decay was observed after 100,000 cycles. The excellent electrochemical performance is due to the combination of a high specific surface area with a fraction of mesopores and highly stable structure.

  4. High-current carbon-epoxy capillary cathode

    Science.gov (United States)

    Gleizer, J. Z.; Queller, T.; Bliokh, Yu.; Yatom, S.; Vekselman, V.; Krasik, Ya. E.; Bernshtam, V.

    2012-07-01

    The results of experiments on the reproducible generation of an electron beam having a high current density of up to 300 A/cm2 and a satisfactorily uniform cross-sectional distribution of current density in a ˜200 kV, ˜450 ns vacuum diode with a carbon-epoxy capillary cathode are presented. It was found that the source of the electrons is the plasma formed as a result of flashover inside the capillaries. It is shown that the plasma formation occurs at an electric field ≤15 kV/cm and that the cathode sustains thousands of pulses without degradation in its emission properties. Time- and space-resolved visible light observation and spectroscopy analyses were used to determine the cathode plasma's density, temperature, and expansion velocity. It was found that the density of the cathode plasma decreases rapidly in relation to the distance from the cathode. In addition, it was found that the main reason for the short-circuiting of the accelerating gap is the formation and expansion of the anode plasma. Finally, it was shown that when an external guiding magnetic field is present, the injection of the electron beam into the drift space with a current amplitude exceeding its critical value changes the radial distribution of the current density of the electron beam because the inner electrons are reflected from the virtual cathode.

  5. Study on rolling process optimization of high carbon steel wire

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The existing problems in the manufacture of SWRH82B high carbon steel wire were discussed by sampling and testing the microstructure and properties of the steel from the workshop. To solve the problems, the experimental parameters for thermal simulation were optimized, and the thermal simulating experiments were carried out on a Gleeble1500 thermal simulator. The process parameters for the manufacture were optimized after analysis of the data, and the productive experiments were performed after the water box in front of the no-twist blocks was reconstructed, to control the temperature of the loop layer. The results from the productive experiments showed that the cooling rate of 10-15 ℃/s was reasonable before phase transformation, about 5℃/s during phase wire was increased to 1150-1170 MPa with an increase of 20-30 MPa, the percentage reduction of section was to 34%-36% with an increase of 1%-3% by testing the finished products after reconstruction.

  6. Method and device for secure, high-density tritium bonded with carbon

    Energy Technology Data Exchange (ETDEWEB)

    Wertsching, Alan Kevin; Trantor, Troy Joseph; Ebner, Matthias Anthony; Norby, Brad Curtis

    2016-04-05

    A method and device for producing secure, high-density tritium bonded with carbon. A substrate comprising carbon is provided. A precursor is intercalated between carbon in the substrate. The precursor intercalated in the substrate is irradiated until at least a portion of the precursor, preferably a majority of the precursor, is transmutated into tritium and bonds with carbon of the substrate forming bonded tritium. The resulting bonded tritium, tritium bonded with carbon, produces electrons via beta decay. The substrate is preferably a substrate from the list of substrates consisting of highly-ordered pyrolytic graphite, carbon fibers, carbon nanotunes, buckministerfullerenes, and combinations thereof. The precursor is preferably boron-10, more preferably lithium-6. Preferably, thermal neutrons are used to irradiate the precursor. The resulting bonded tritium is preferably used to generate electricity either directly or indirectly.

  7. Fundamental properties of high-quality carbon nanofoam: from low to high density

    Directory of Open Access Journals (Sweden)

    Natalie Frese

    2016-12-01

    Full Text Available Highly uniform samples of carbon nanofoam from hydrothermal sucrose carbonization were studied by helium ion microscopy (HIM, X-ray photoelectron spectroscopy (XPS, and Raman spectroscopy. Foams with different densities were produced by changing the process temperature in the autoclave reactor. This work illustrates how the geometrical structure, electron core levels, and the vibrational signatures change when the density of the foams is varied. We find that the low-density foams have very uniform structure consisting of micropearls with ≈2–3 μm average diameter. Higher density foams contain larger-sized micropearls (≈6–9 μm diameter which often coalesced to form nonspherical μm-sized units. Both, low- and high-density foams are comprised of predominantly sp2-type carbon. The higher density foams, however, show an advanced graphitization degree and a stronger sp3-type electronic contribution, related to the inclusion of sp3 connections in their surface network.

  8. Is CT angiography of the pulmonary arteries indicated in patients with high clinical probability of pulmonary embolism?

    Science.gov (United States)

    Martínez Montesinos, L; Plasencia Martínez, J M; García Santos, J M

    2017-06-30

    When a diagnostic test confirms clinical suspicion, the indicated treatment can be administered. A problem arises when the diagnostic test does not confirm the initially suspected diagnosis; when the suspicion is grounded in clinically validated predictive rules and is high, the problem is even worse. This situation arises in up to 40% of patients with high suspicion for acute pulmonary embolism, raising the question of whether CT angiography of the pulmonary arteries should be done systematically. This paper reviews the literature about this issue and lays out the best evidence about the relevant recommendations for patients with high clinical suspicion of acute pulmonary embolism and negative findings on CT angiography. It also explains the probabilistic concepts derived from Bayes' theorem that can be useful for ascertaining the most appropriate approach in these patients. Copyright © 2017 SERAM. Publicado por Elsevier España, S.L.U. All rights reserved.

  9. Predictors and prognostic impact of silent coronary artery disease in asymptomatic high-risk patients with diabetes mellitus.

    Science.gov (United States)

    Zellweger, Michael J; Haaf, Philip; Maraun, Michael; Osterhues, Hans H; Keller, Ulrich; Müller-Brand, Jan; Jeger, Raban; Pfister, Otmar; Brinkert, Miriam; Burkard, Thilo; Pfisterer, Matthias

    2017-10-01

    Evaluation of predictors of silent coronary artery disease (SCAD) in high-risk asymptomatic diabetic patients and to evaluate their two-year outcome. Four hundred diabetic patients without prior CAD but at high CAD risk underwent myocardial perfusion scintigraphy (MPS) in this prospective multicentre outcome trial. MPS were abnormal in 22% of patients. Male sex (OR 2.223, 1.152-4.290; p=0.017), diabetes duration (OR 1.049,1.015-1.085; p=0·005), peripheral artery disease (OR 2.134, 1·150-3.961; p=0.016), smoking (OR 2.064, 1.109-3.839; p=0·022), systolic blood pressure (OR 1.014, 1.00-1.03, p=0·056), brain natriuretic peptide (OR 1.002, 1.001-1.004, p=0·005) independently predicted an abnormal MPS: if 3 predictors were present, 3.2% and 47% patients had an abnormal MPS, respectively (p10%, respectively (each p3 predictors, almost 50% of patients had an abnormal MPS. They may benefit from screening by MPS since the extent of the MPS abnormality discriminated clearly between a favourable compared to a bad 2-year outcome. However, even highest risk patients without objective evidence of CAD had a benign prognosis without need for specific evaluation or therapy. ISRCTN87953632. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

  10. High temperature annealing studies of strontium ion implanted glassy carbon

    Energy Technology Data Exchange (ETDEWEB)

    Odutemowo, O.S., E-mail: u12052613@tuks.co.za [Department of Physics, University of Pretoria, Pretoria 0002 (South Africa); Malherbe, J.B.; Prinsloo, L.; Langa, D.F. [Department of Physics, University of Pretoria, Pretoria 0002 (South Africa); Wendler, E. [Institut für Festkörperphysik, Friedrich-Schiller University, Jena (Germany)

    2016-03-15

    Glassy carbon samples were implanted with 200 keV strontium ions to a fluence of 2 × 10{sup 16} ions/cm{sup 2} at room temperature. Analysis with Raman spectroscopy showed that ion bombardment amorphises the glassy carbon structure. Partial recovery of the glassy carbon structure was achieved after the implanted sample was vacuum annealed at 900 °C for 1 h. Annealing the strontium ion bombarded sample at 2000 °C for 5 h resulted in recovery of the glassy carbon substrate with the intensity of the D peak becoming lower than that of the pristine glassy carbon. Rutherford backscattering spectroscopy (RBS) showed that the implanted strontium diffused towards the surface of the glassy carbon after annealing the sample at 900 °C. This diffusion was also accompanied by loss of the implanted strontium. Comparison between the as-implanted and 900 °C depth profiles showed that less than 30% of the strontium was retained in the glassy carbon after heat treatment at 900 °C. The RBS profile after annealing at 2000 °C indicated that no strontium ions were retained after heat treatment at this temperature.

  11. High temperature annealing studies of strontium ion implanted glassy carbon

    Science.gov (United States)

    Odutemowo, O. S.; Malherbe, J. B.; Prinsloo, L.; Langa, D. F.; Wendler, E.

    2016-03-01

    Glassy carbon samples were implanted with 200 keV strontium ions to a fluence of 2 × 1016 ions/cm2 at room temperature. Analysis with Raman spectroscopy showed that ion bombardment amorphises the glassy carbon structure. Partial recovery of the glassy carbon structure was achieved after the implanted sample was vacuum annealed at 900 °C for 1 h. Annealing the strontium ion bombarded sample at 2000 °C for 5 h resulted in recovery of the glassy carbon substrate with the intensity of the D peak becoming lower than that of the pristine glassy carbon. Rutherford backscattering spectroscopy (RBS) showed that the implanted strontium diffused towards the surface of the glassy carbon after annealing the sample at 900 °C. This diffusion was also accompanied by loss of the implanted strontium. Comparison between the as-implanted and 900 °C depth profiles showed that less than 30% of the strontium was retained in the glassy carbon after heat treatment at 900 °C. The RBS profile after annealing at 2000 °C indicated that no strontium ions were retained after heat treatment at this temperature.

  12. High-resolution NMR spectra of n-alkanes penetrating into carbon fibers and of protons in carbon fibers.

    Science.gov (United States)

    Yamazaki, Yuya; Kobayashi, Nobuaki; Nikki, Kunio; Kuwahara, Daisuke

    2008-08-01

    We present a simple NMR method for microscopically exploring the local environment in carbon fibers. The method utilizes n-alkanes as probe molecules, where the n-alkanes penetrate carbon fibers of interest. The high-resolution (1)H NMR spectra for a mixture of a carbon fiber and n-alkanes acquired by this method show a shift of the resonance line, which is due to the local structure of the fiber. The utility of this method is discussed on the basis of the (1)H NMR spectra obtained. In addition, the (1)H distribution and the local motion in the structure of the carbon fiber are revealed in view of the (1)H NMR spectra.

  13. Pulmonary Artery Invasion, High-Dose Radiation, and Overall Survival in Patients With Non-Small Cell Lung Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Han, Cheng-Bo [Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan (United States); Department of Oncology, Shengjing Hospital of China Medical University, Shenyang (China); Wang, Wei-Li [Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan (United States); Department of Radiation Oncology, Fourth Hospital of China Medical University, Shenyang (China); Quint, Leslie [Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan (United States); Xue, Jian-Xin [Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan (United States); Department of Thoracic Oncology, Cancer Center, West China Hospital, Sichuan University, Chengdu (China); Matuszak, Martha; Ten Haken, Randall [Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan (United States); Kong, Feng-Ming, E-mail: fkong@gru.edu [Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan (United States)

    2014-06-01

    Purpose: To investigate whether high-dose radiation to the pulmonary artery (PA) affects overall survival (OS) in patients with non-small cell lung cancer (NSCLC). Methods and Materials: Patients with medically inoperable/unresectable NSCLC treated with definitive radiation therapy in prospective studies were eligible for this study. Pulmonary artery involvement was defined on the basis of pretreatment chest CT and positron emission tomography/CT fusion. Pulmonary artery was contoured according to the Radiation Therapy Oncology Group protocol 1106 atlas, and dose-volume histograms were generated. Results: A total of 100 patients with a minimum follow-up of 1 year for surviving patients were enrolled: 82.0% underwent concurrent chemoradiation therapy. Radiation dose ranged from 60 to 85.5 Gy in 30-37 fractions. Patients with PA invasion of grade ≤2, 3, 4, and 5 had 1-year OS and median survival of 67% and 25.4 months (95% confidence interval [CI] 15.7-35.1), 62% and 22.2 months (95% CI 5.8-38.6), 90% and 35.8 months (95% CI 28.4-43.2), and 50% and 7.0 months, respectively (P=.601). Two of the 4 patients with grade 5 PA invasion died suddenly from massive hemorrhage at 3 and 4.5 months after completion of radiation therapy. Maximum and mean doses to PA were not significantly associated with OS. The V45, V50, V55, and V60 of PA were correlated significantly with a worse OS (P<.05). Patients with V45 >70% or V60 >37% had significantly worse OS (13.3 vs 37.9 months, P<.001, and 13.8 vs 37.9 months, P=.04, respectively). Conclusions: Grade 5 PA invasion and PA volume receiving more than 45-60 Gy may be associated with inferior OS in patients with advanced NSCLC treated with concurrent chemoradiation.

  14. Highly Ordered Carbon Nanotube Arrays with Open Ends Grown in Anodic Alumina Nanoholes

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Highly ordered multiwalled carbon nanotube arrays were fabricated by pyrolysis of acetylene within anodic alumina templates.Nanotubes are very uniform in diameter and open at both ends. High resolution transmission electron microscopy and electron diffraction analysis show that the carbon nanotubes are well graphitized. These standing and open carbon nanotubes are possible to offer a potential elegant technique for electron emitting devices,chemical functionalization and nanotube composites.

  15. Carbonate mineral dissolution kinetics in high pressure experiments

    Science.gov (United States)

    Dethlefsen, F.; Dörr, C.; Schäfer, D.; Ebert, M.

    2012-04-01

    The potential CO2 reservoirs in the North German Basin are overlain by a series of Mesozoic barrier rocks and aquifers and finally mostly by Tertiary and Quaternary close-to-surface aquifers. The unexpected rise of stored CO2 from its reservoir into close-to-surface aquifer systems, perhaps through a broken well casing, may pose a threat to groundwater quality because of the acidifying effect of CO2 dissolution in water. The consequences may be further worsening of the groundwater quality due to the mobilization of heavy metals. Buffer mechanisms counteracting the acidification are for instance the dissolution of carbonates. Carbonate dissolution kinetics is comparably fast and carbonates can be abundant in close-to-surface aquifers. The disadvantages of batch experiments compared to column experiments in order to determine rate constants are well known and have for instance been described by v. GRINSVEN and RIEMSDIJK (1992). Therefore, we have designed, developed, tested, and used a high-pressure laboratory column system to simulate aquifer conditions in a flow through setup within the CO2-MoPa project. The calcite dissolution kinetics was determined for CO2-pressures of 6, 10, and 50 bars. The results were evaluated by using the PHREEQC code with a 1-D reactive transport model, applying a LASAGA (1984) -type kinetic dissolution equation (PALANDRI and KHARAKA, 2004; eq. 7). While PALANDRI and KHARAKA (2004) gave calcite dissolution rate constants originating from batch experiments of log kacid = -0.3 and log kneutral = -5.81, the data of the column experiment were best fitted using log kacid = -2.3 and log kneutral = -7.81, so that the rate constants fitted using the lab experiment applying 50 bars pCO2 were approximately 100 times lower than according to the literature data. Rate constants of experiments performed at less CO2 pressure (pCO2 = 6 bars: log kacid = -1.78; log kneutral = -7.29) were only 30 times lower than literature data. These discrepancies in the

  16. Highly porous carbon from a natural cellulose fiber as high efficiency sorbent for lead in waste water.

    Science.gov (United States)

    Ilangovan, Manikandan; Guna, Vijaykumar; Olivera, Sharon; Ravi, Ashwini; Muralidhara, H B; Santosh, M S; Reddy, Narendra

    2017-08-24

    The persistence of hollow centre in the carbon obtained from milkweed floss provides exceptional sorption characteristics, not seen in common biomasses or their derivatives. A considerably high sorption of 320mg of lead per gram of milkweed carbon was achieved without any chemical modification to the biomass. In this research, we have carbonized milkweed floss and used the carbon as a sorbent for lead in waste water. A high surface area of 170m(2)g(-1) and pore volume of 1.07cm(3)g(-1) was seen in the carbon. Almost complete removal (>99% efficiency) of lead could be achieved within 5min when the concentration of lead in the solution was 100ppm, close to that prevailing in industrial waste water. SEM images showed that the carbon was hollow and confocal images confirmed that the sorbate could penetrate inside the hollow tube. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. Formation of high-carbon abrasion-resistant surface layers when high-energy heating by high-frequency currents

    Science.gov (United States)

    Plotnikova, N. V.; Skeeba, V. Yu; Martyushev, N. V.; Miller, R. A.; Rubtsova, N. S.

    2016-11-01

    The paper shows the possibility of carburization of low-carbon steel surface layers using high-frequency currents. The mathematical modeling of carburization using high-energy heating by high-frequency currents (HEH HFC) has been carried out, the temperature fields formed during the given processing have been calculated, as well as the structural changes in the surface layers have been simulated. The features of the structure formation in the surface layers of low-carbon steel after carburizing via HEH HFC have been determined by optical and scanning microscopy, which is confirmed by the computational models. The rational mode of fusion via HEH HFC has also been determined (power density of the source qs = (1.5 ... 4.0) • 108 W m-2, (the relative travel speed of parts Vp = 5 ... 100 mm / sec), with forming the compressive retained stresses in the surface layer (σRS ≈ -300 ... -400 MPa).

  18. Development and Evaluation of Carbon-Carbon Threaded Fasteners for High Temperature Applications

    Directory of Open Access Journals (Sweden)

    Juhi Kushwaha

    2012-09-01

    Full Text Available Carbon-Carbon (C-C threaded fasteners have been developed for joining C-C composites experiencing temperature above 1500 ˚C. The fasteners were fabricated from spun yarn graphitized carbon fabric through resin route and from needle punched carbon felt through pitch route techniques. The preforms were processed with multiple cycles of impregnation, carbonisation, and graphitisation up to densities of 1.78 gcm-3 and 1.90 gcm-3. Densification process cycles were repeated to obtain composites with reduced porosity and improved thermo-mechanical properties. Material evaluation of C-C fasteners is discussed and compared with existing graphite fasteners used in industrial and aerospace sectors. Scanning electron microscopy was also carried out to study microstructure of fractured specimens.Defence Science Journal, 2012, 62(5, pp.348-355, DOI:http://dx.doi.org/10.14429/dsj.62.2395

  19. Highly Increased Flow-Induced Power Generation on Plasmonically Carbonized Single-Walled Carbon Nanotube .

    Science.gov (United States)

    Kim, Jangheon; Lee, Janghyeon; Kim, Soohyun; Jung, Wonsuk

    2016-11-09

    We generate networks and carbonization between individualized single-walled carbon nanotubes (SWCNTs) by an optimized plasmonic heating process using a halogen lamp to improve electrical properties for flow-induced energy harvesting. These properties were characterized by Raman spectra, a field-emission-scanning probe, transmission electron microscopy, atomic force microscopy and thermographic camera. The electrical sheet resistance of carbonized SWCNTs was decreased to 2.71 kΩ/□, 2.5 times smaller than normal-SWCNTs. We demonstrated flow-induced voltage generation on SWCNTs at various ion concentrations of NaCl. The generated voltage and current for the carbonized-SWCNTs were 9.5 and 23.5 times larger than for the normal-SWCNTs, respectively, based on the electron dragging mechanism.

  20. High-resolution photocurrent mapping of carbon nanostructures.

    Science.gov (United States)

    Burghard, Marko; Mews, Alf

    2012-07-24

    The spatial resolution of photocurrent measurements on carbon nanostructures has reached 20 nm, as demonstrated by Hartschuh and co-workers for individual carbon nanotubes in this issue of ACS Nano. In this Perspective, we provide a brief overview of the applications of scanning photocurrent microscopy to various one- and two-dimensional nanostructures and highlight the importance of the optical antenna concept for future studies of the optoelectronic properties of hybrid nanostructures.

  1. High-definition computed tomography for coronary artery stents imaging: Initial evaluation of the optimal reconstruction algorithm

    Energy Technology Data Exchange (ETDEWEB)

    Cui, Xiaoming, E-mail: mmayzy2008@126.com; Li, Tao, E-mail: litaofeivip@163.com; Li, Xin, E-mail: lx0803@sina.com.cn; Zhou, Weihua, E-mail: wangxue0606@gmail.com

    2015-05-15

    Highlights: • High-resolution scan mode is appropriate for imaging coronary stent. • HD-detail reconstruction algorithm is stent-dedicated kernel. • The intrastent lumen visibility also depends on stent diameter and material. - Abstract: Objective: The aim of this study was to evaluate the in vivo performance of four image reconstruction algorithms in a high-definition CT (HDCT) scanner with improved spatial resolution for the evaluation of coronary artery stents and intrastent lumina. Materials and methods: Thirty-nine consecutive patients with a total of 71 implanted coronary stents underwent coronary CT angiography (CCTA) on a HDCT (Discovery CT 750 HD; GE Healthcare) with the high-resolution scanning mode. Four different reconstruction algorithms (HD-stand, HD-detail; HD-stand-plus; HD-detail-plus) were applied to reconstruct the stented coronary arteries. Image quality for stent characterization was assessed. Image noise and intrastent luminal diameter were measured. The relationship between the measurement of inner stent diameter (ISD) and the true stent diameter (TSD) and stent type were analysed. Results: The stent-dedicated kernel (HD-detail) offered the highest percentage (53.5%) of good image quality for stent characterization and the highest ratio (68.0 ± 8.4%) of visible stent lumen/true stent lumen for luminal diameter measurement at the expense of an increased overall image noise. The Pearson correlation coefficient between the ISD and TSD measurement and spearman correlation coefficient between the ISD measurement and stent type were 0.83 and 0.48, respectively. Conclusions: Compared with standard reconstruction algorithms, high-definition CT imaging technique with dedicated high-resolution reconstruction algorithm provides more accurate stent characterization and intrastent luminal diameter measurement.

  2. Coronary Artery Imaging in Children

    Science.gov (United States)

    2015-01-01

    Coronary artery problems in children usually have a significant impact on both short-term and long-term outcomes. Early and accurate diagnosis, therefore, is crucial but technically challenging due to the small size of the coronary artery, high heart rates, and limited cooperation of children. Coronary artery visibility on CT and MRI in children is considerably improved with recent technical advancements. Consequently, CT and MRI are increasingly used for evaluating various congenital and acquired coronary artery abnormalities in children, such as coronary artery anomalies, aberrant coronary artery anatomy specific to congenital heart disease, Kawasaki disease, Williams syndrome, and cardiac allograft vasculopathy. PMID:25741188

  3. Carbonation of subduction-zone serpentinite (high-pressure ophicarbonate; Ligurian Western Alps) and implications for the deep carbon cycling

    Science.gov (United States)

    Scambelluri, Marco; Bebout, Gray E.; Belmonte, Donato; Gilio, Mattia; Campomenosi, Nicola; Collins, Nathan; Crispini, Laura

    2016-05-01

    Much of the long-term carbon cycle in solid earth occurs in subduction zones, where processes of devolatilization, partial melting of carbonated rocks, and dissolution of carbonate minerals lead to the return of CO2 to the atmosphere via volcanic degassing. Release of COH fluids from hydrous and carbonate minerals influences C recycling and magmatism at subduction zones. Contradictory interpretations exist regarding the retention/storage of C in subducting plates and in the forearc to subarc mantle. Several lines of evidence indicate mobility of C, of uncertain magnitude, in forearcs. A poorly constrained fraction of the 40-115 Mt/yr of C initially subducted is released into fluids (by decarbonation and/or carbonate dissolution) and 18-43 Mt/yr is returned at arc volcanoes. Current estimates suggest the amount of C released into subduction fluids is greater than that degassed at arc volcanoes: the imbalance could reflect C subduction into the deeper mantle, beyond subarc regions, or storage of C in forearc/subarc reservoirs. We examine the fate of C in plate-interface ultramafic rocks, and by analogy serpentinized mantle wedge, via study of fluid-rock evolution of marble and variably carbonated serpentinite in the Ligurian Alps. Based on petrography, major and trace element concentrations, and carbonate C and O isotope compositions, we demonstrate that serpentinite dehydration at 2-2.5 GPa, 550 °C released aqueous fluids triggering breakdown of dolomite in nearby marbles, thus releasing C into fluids. Carbonate + olivine veins document flow of COH fluids and that the interaction of these COH fluids with serpentinite led to the formation of high-P carbonated ultramafic-rock domains (high-P ophicarbonates). We estimate that this could result in the retention of ∼0.5-2.0 Mt C/yr in such rocks along subduction interfaces. As another means of C storage, 1 to 3 km-thick layers of serpentinized forearc mantle wedge containing 50 modal % dolomite could sequester 1.62 to

  4. High power density electrodes for Carbon supercapacitor applications

    Energy Technology Data Exchange (ETDEWEB)

    Portet, C.; Taberna, P.L.; Simon, P.; Flahaut, E.; Laberty-Robert, C. [CIRIMAT, UMR CNRS 5085, 118 Route de Narbonne 31062 Toulouse Cedex (France)

    2005-07-25

    This paper presents results obtained with 4 cm{sup 2} Carbon/Carbon supercapacitors cells in organic electrolyte. In the first approach, a surface treatment for Al current collector foil via the sol-gel route has been used in order to decrease the Al/active material interface resistance. Performances obtained with this original process are: a low equivalent series resistance (ESR) of 0.5 {omega} cm{sup 2} and a specific capacitance of 95 F g{sup -1} of activated carbon. Then, supercapacitors assembled with treated Al foil and active material containing activated carbon/carbon nanotubes (CNTs) with different compositions have been studied. Galvanostatic cycling measurements show that when CNTs content increases, both ESR and specific capacitance are decreased. Fifteen percent appears to be a good compromise between stored energy and delivered power with an ESR of 0.4 {omega} cm{sup 2} and a specific capacitance of 93 F g{sup -1} of carbonaceous active material. Finally, cells frequency behaviour has been characterized by Electrochemical Impedance Spectroscopy. The relaxation time constant of cells decreases when the CNTs content increases. For 15% of CNTs, the time constant is about 30% lower as compared to a cell using pure activated carbon-based electrodes leading to a higher delivered power. (author)

  5. Malignant hepatic epithelioid hemangioendothelioma with high-output heart failure: successful management of heart failure with transcatheter arterial chemoembolization.

    Science.gov (United States)

    Hsu, Chien-Yi; Liu, Yao-Chung; Li, Chung-Pin; Huang, Po-Hsun; Lin, Chin-Hsuan; Chao, Yee

    2014-06-01

    A 73-year-old woman was admitted to hospital because of progressive dyspnea on exertion. Computed tomography revealed a large hepatic tumor, which was proved to be a hepatic epithelioid hemangioendothelioma (EHE). Echocardiography demonstrated high cardiac output, for which the tumor was considered to be the leading cause. A transcatheter arterial chemoembolization (TACE) was performed sequentially at 1-month intervals to reduce the size of the hepatic tumor, and this temporarily improved the patient's cardiac condition and quality of life. In this case, we successfully used TACE in the treatment of hepatic EHE with high-output heart failure. TACE is a reasonable choice of treatment both for managing malignant hepatic tumors and resolving low systemic vascular resistance by embolization of the abnormal neoangiogenic vessels. Nevertheless, clinicians should be aware of the potential adverse effect of hepatic decompensation induced by TACE, especially when the tumor involvement is widespread and poorly preserved hepatic function is encountered.

  6. High-resolution coronary MR angiography for evaluation of patients with anomalous coronary arteries: visualization of the intramural segment

    Energy Technology Data Exchange (ETDEWEB)

    Biko, David M. [UCSF Benioff Children' s Hospital Oakland, Department of Diagnostic Imaging, Oakland, CA (United States); The Children' s Hospital of Philadelphia, Department of Radiology, Philadelphia, PA (United States); Chung, Claudia; Chung, Taylor [UCSF Benioff Children' s Hospital Oakland, Department of Diagnostic Imaging, Oakland, CA (United States); Hitt, David M. [Philips Healthcare, Cleveland, OH (United States); Kurio, Gregory [UCSF Benioff Children' s Hospital Oakland, Department of Cardiology, Oakland, CA (United States); Reinhartz, Olaf [UCSF Benioff Children' s Hospital Oakland, Department of Cardiac Surgery, Oakland, CA (United States)

    2015-08-15

    Anomalous origin of the coronary artery from the contralateral coronary sinus is a rare coronary anomaly associated with sudden death. The inter-arterial course is most closely associated with sudden death, but it has been suggested that the presence of an intramural segment of a right anomalous coronary is associated with more symptoms and therefore may be an important criterion for intervention in these patients. To demonstrate that MR angiography can accurately determine the presence or absence of an intramural segment in an anomalous coronary artery. All studies of children who underwent MR angiography for the evaluation of an anomalous coronary artery were retrospectively reviewed by two pediatric radiologists in consensus. Criteria for an intramural anomalous coronary artery were the presence of a small or slit-like ostium and the relative smaller size of the proximal intramural portion of the coronary artery in relation to the more distal epicardial coronary artery. The anomalous coronary artery was classified as not intramural if these two findings were absent. These findings were correlated with operative reports confirming the presence or absence of an intramural segment. Twelve patients (86%) met MR angiography criteria for the presence of an intramural course. Only 2 patients (14%) met MR angiography criteria for a non-intramural course. When correlating with intraoperative findings, MR angiography was successful in distinguishing between intramural and non-intramural anomalous coronary arteries in all cases (P = 0.01). MR angiography may be able to reliably identify the intramural segment of an anomalous coronary artery in older children using the imaging criteria of a small or slit-like ostium and relative decrease in size of the proximal portion of the anomalous coronary artery compared to the distal portion of the anomalous coronary artery. Determining the presence of the intramural segment may help with surgical planning and may be an important

  7. High-sensitivity C-reactive protein and exercise-induced changes in subjects suspected of coronary artery disease

    DEFF Research Database (Denmark)

    Mouridsen, Mette Rauhe; Nielsen, Olav Wendelboe; Carlsen, Christian Malchau

    2014-01-01

    BACKGROUND: Inflammation plays a major role in the development of atherosclerosis. We wanted to investigate the effects of exercise on high-sensitivity (hs) C-reactive protein (CRP) in subjects who were suspected of having coronary artery disease (CAD). METHODS: Blood samples were obtained before......, 5 minutes after, and 20 hours after an exercise test in 155 subjects who were suspected of CAD. Coronary anatomy was evaluated by computed tomography coronary angiography and/or coronary angiography. RESULTS: Median baseline hs-CRP was higher in subjects with ≥50% coronary artery lumen diameter...... stenosis (n=41), compared with non-CAD-subjects (n=114), 2.93 mg/L (interquartile range 1.03-5.06 mg/L) and 1.30 mg/L (interquartile range 0.76-2.74 mg/L), respectively, P=0.007. In multivariate analyses testing conventional risk factors, hs-CRP proved borderline significant, odds ratio =2.32, P=0...

  8. Relation Between Monocyte to High-Density Lipoprotein Cholesterol Ratio With Presence and Severity of Isolated Coronary Artery Ectasia.

    Science.gov (United States)

    Kundi, Harun; Gok, Murat; Kiziltunc, Emrullah; Cetin, Mustafa; Cicekcioglu, Hulya; Cetin, Zehra Guven; Karayigit, Orhan; Ornek, Ender

    2015-12-01

    The aim of this study was to investigate an easily available inflammatory and oxidative stress marker and monocyte to high-density lipoprotein cholesterol ratio (MHR) in patients with coronary artery ectasia (CAE). The study population included 405 patients of which 135 patients had isolated CAE, 135 patients had obstructive coronary artery disease (CAD), and 135 patients had normal coronary angiograms (NCAs). The severity of isolated CAE was determined according to the Markis classification. The MHR was significantly greater in patients with isolated CAE than those with obstructive CAD and NCAs: 14.8 (11.6 to 19.8), 11.4 (9.6 to 13.5), 9.8 (7.5 to 11.9), respectively. Linear regression analyses showed that MHR and C-reactive protein were significantly related with the severity of isolated CAE. In conclusion, the MHR is significantly greater in patients with CAE compared to controls with obstructive CAD and NCAs, and MHR is associated with the severity of CAE. Copyright © 2015 Elsevier Inc. All rights reserved.

  9. Automated carbon dioxide digital angiography for lower-limb arterial disease evaluation: safety assessment and comparison with standard iodinated contrast media angiography.

    Science.gov (United States)

    Scalise, Filippo; Novelli, Eugenio; Auguadro, Carla; Casali, Valentina; Manfredi, Mariella; Zannoli, Romano

    2015-01-01

    Carbon dioxide (CO2) has been validated as a contrast agent in a large series of studies. A particular advantages of CO2 over iodinated contrast medium (ICM) is the absence of nephrotoxicity and allergic reactions. One of the limitations of CO2 angiography is the difficulty of CO2 manual injection due to its compressibility. The manual gas injection does not permit optimal control of the gas output. Development of an automated CO2 injector has overcome these problems. This study compares the feasibility, safety, and diagnostic accuracy of automated CO2 digital subtraction angiography (DSA) in comparison with ICM-DSA in the evaluation of critical limb ischemic (CLI) patients. We performed DSA with both CO2 and ICM on 40 consecutive CLI patients and directly compared the two techniques. Sixteen females and 24 males participated in the study (mean age, 71.7 years). We assessed the diagnostic accuracy of CO2 in identifying arterial stenosis in the lower limb, with ICM-DSA used as the gold standard. The overall diagnostic accuracy of CO2-DSA was 96.9% (sensitivity, 99.0%; specificity, 96.1%; positive predictive value, 91.1%; negative predictive value, 99.6%). Tolerable minor symptoms occurred in 3 patients. No allergic reactions or significant decline in renal function were observed in patients receiving the CO2 injection. Carbon dioxide DSA is a valuable and safe alternative to traditional ICM-DSA for evaluating CLI patients. This modality should be considered as the standard choice for CLI patients undergoing angiographic evaluation who are known to have renal insufficiency or contrast allergy.

  10. Quo vadis, carbon? High resolution tracing of xylem and phloem carbon transport and release in trees

    Science.gov (United States)

    Ingrisch, J.; Bloemen, J.; Bahn, M.

    2016-12-01

    Carbon (C) allocation defines the flows of C between plant organs, and between storage pools and metabolic processes and is therefore considered an important determinant of ecosystem C budgets and their responses to climate change. In trees, assimilates derived from leaf photosynthesis are transported as sugars via the phloem to above- and below-ground sink tissues, where partitioning between growth, storage, and respiration occurs. At the same time, above- and below-ground respired CO2 can be dissolved in water and transported in the xylem tissue, thereby representing a transport pathway opposite to the downward transport of sugars along the phloem. So far, it is unclear to what extent these transport pathways interact, for instance by lateral transport of C, and contribute to above- and belowground respiratory fluxes to the atmosphere. We performed a combined canopy and stem infusion 13C labeling study on six year old potted oak (Quercus rubra) trees to trace C transport along the phloem and xylem, respectively, in order to investigate the role of both transport pathways in C allocation. In addition, high-resolution laser-based measurements of the isotopic composition of stem and soil CO2 efflux were used to monitor the contribution of both pathways to respiratory fluxes. Additional tissue analysis was performed to analyze the occurrence of lateral transport of C between the phloem and xylem transport pathway. Our results will permit disentangling the contribution of metabolic versus xylem and phloem transport processes to stem and soil CO2 efflux and give insight into lateral C transport between xylem and phloem in trees.

  11. Microwave-assisted synthesis of high-loading, highly dispersed Pt/carbon aerogel catalyst for direct methanol fuel cell

    Indian Academy of Sciences (India)

    Zhijun Guo; Hong Zhu; Xinwei Zhang; Fanghui Wang; Yubao Guo; Yongsheng Wei

    2011-06-01

    A Pt supported on carbon aerogel catalyst has been synthesized by the microwave-assisted polyol process. The Pt supported on carbon aerogel catalyst was characterized by high resolution transmission electron microscopy and X-ray diffraction. The results show a uniform dispersion of spherical Pt nanoparticles 2.5–3.0 nm in diameter. Cyclic voltammetry and chronoamperometry were used to evaluate the electrocatalytic activity of the Pt/carbon aerogel catalyst for methanol oxidation at room temperature. The Pt/carbon aerogel catalyst shows higher electrochemical catalytic activity and stability for methanol oxidation than a commercial Pt/C catalyst of the same Pt loading.

  12. High temperature stability of onion-like carbon vs highly oriented pyrolytic graphite.

    Directory of Open Access Journals (Sweden)

    Alessandro Latini

    Full Text Available The thermodynamic stability of onion-like carbon (OLC nanostructures with respect to highly oriented pyrolytic graphite (HOPG was determined in the interval 765-1030 K by the electromotive force (emf measurements of solid electrolyte galvanic cell: (Low Pt|Cr3C2,CrF2,OLC|CaF2s.c.|Cr3C2,CrF2,HOPG|Pt (High. The free energy change of transformation HOPG = OLC was found positive below 920.6 K crossing the zero value at this temperature. Its trend with temperature was well described by a 3rd degree polynomial. The unexpected too high values of [Formula: see text] jointly to the HR-TEM, STEM and EELS evidences that showed OLC completely embedded in rigid cages made of a Cr3C2/CrF2 matrix, suggested that carbon in the electrodes experienced different internal pressures. This was confirmed by the evaluation under constant volume of [dP/dT by the α/κ ratio for OLC (0.5 MPa K(-1 and HOPG (8 Pa K(-1 where α and κ are the isobaric thermal expansion and isothermal compressibility coefficients, respectively. The temperature dependency of the pressure was derived and utilized to calculate the enthalpy and entropy changes as function of temperature and pressure. The highest value of the internal pressure experienced by OLC was calculated to be about 7 GPa at the highest temperature. At 920.6 K, ΔrH and ΔrS values are 95.8 kJ mol(-1 and 104.1 JK(-1 mol(-1, respectively. The surface contributions to the energetic of the system were evaluated and they were found negligible compared with the bulk terms. As a consequence of the high internal pressure, the values of the enthalpy and entropy changes were mainly attributed to the formation of carbon defects in OLC considered as multishell fullerenes. The change of the carbon defect fraction is reported as a function of temperature.

  13. High temperature stability of onion-like carbon vs highly oriented pyrolytic graphite.

    Science.gov (United States)

    Latini, Alessandro; Tomellini, Massimo; Lazzarini, Laura; Bertoni, Giovanni; Gazzoli, Delia; Bossa, Luigi; Gozzi, Daniele

    2014-01-01

    The thermodynamic stability of onion-like carbon (OLC) nanostructures with respect to highly oriented pyrolytic graphite (HOPG) was determined in the interval 765-1030 K by the electromotive force (emf) measurements of solid electrolyte galvanic cell: (Low) Pt|Cr3C2,CrF2,OLC|CaF2s.c.|Cr3C2,CrF2,HOPG|Pt (High). The free energy change of transformation HOPG = OLC was found positive below 920.6 K crossing the zero value at this temperature. Its trend with temperature was well described by a 3rd degree polynomial. The unexpected too high values of [Formula: see text] jointly to the HR-TEM, STEM and EELS evidences that showed OLC completely embedded in rigid cages made of a Cr3C2/CrF2 matrix, suggested that carbon in the electrodes experienced different internal pressures. This was confirmed by the evaluation under constant volume of [dP/dT by the α/κ ratio for OLC (0.5 MPa K(-1)) and HOPG (8 Pa K(-1)) where α and κ are the isobaric thermal expansion and isothermal compressibility coefficients, respectively. The temperature dependency of the pressure was derived and utilized to calculate the enthalpy and entropy changes as function of temperature and pressure. The highest value of the internal pressure experienced by OLC was calculated to be about 7 GPa at the highest temperature. At 920.6 K, ΔrH and ΔrS values are 95.8 kJ mol(-1) and 104.1 JK(-1) mol(-1), respectively. The surface contributions to the energetic of the system were evaluated and they were found negligible compared with the bulk terms. As a consequence of the high internal pressure, the values of the enthalpy and entropy changes were mainly attributed to the formation of carbon defects in OLC considered as multishell fullerenes. The change of the carbon defect fraction is reported as a function of temperature.

  14. Preparation of activated carbon with high surface area for high-capacity methane storage

    Institute of Scientific and Technical Information of China (English)

    Bingsi Liua; Wenshuo Wanga; Na Wanga; Peter Chak Tong Aub

    2014-01-01

    Activated carbon (AC) was fabricated from corncob, which is cheap and abundant. Experimental parameters such as particle size of corncob, KOH/char weight ratio, and activation temperature and time were optimized to generate AC, which shows high methane sorption capacity. AC has high specific surface area (3227 m2/g), with pore volume and pore size distribution equal to 1.829 cm3/g and ca. 1.7-2.2 nm, respectively. Under the condition of 2◦C and less than 7.8 MPa, methane sorption in the presence of water (Rw=1.4) was as high as 43.7 wt%methane per unit mass of dry AC. The result is significantly higher than those of coconut-derived AC (32 wt%) and ordered mesoporous carbon (41.2 wt%, Rw=4.07) under the same condition. The physical properties and amorphous chaotic structure of AC were characterized by N2 adsorption isotherms, XRD, SEM and HRTEM. Hence, the corncob-derived AC can be considered as a competitive methane-storage material for vehicles, which are run by natural gas.

  15. An asymmetric tubular ceramic-carbonate dual phase membrane for high temperature CO2 separation.

    Science.gov (United States)

    Dong, Xueliang; Ortiz Landeros, José; Lin, Y S

    2013-10-25

    For the first time, a tubular asymmetric ceramic-carbonate dual phase membrane was prepared by a centrifugal casting technique and used for high temperature CO2 separation. This membrane shows high CO2 permeation flux and permeance.

  16. Copper coated carbon fiber reinforced plastics for high and ultra high vacuum applications

    Science.gov (United States)

    Burri, F.; Fertl, M.; Feusi, P.; Henneck, R.; Kirch, K.; Lauss, B.; Rüttimann, P.; Schmidt-Wellenburg, P.; Schnabel, A.; Voigt, J.; Zenner, J.; Zsigmond, G.

    2014-03-01

    We have used copper-coated carbon fiber reinforced plastic (CuCFRP) for the construction of high and ultra-high vacuum recipients. The vacuum performance is found to be comparable to typical stainless steel used for this purpose. In test recipients we have reached pressures of 2E-8 mbar and measured a desorption rate of 1E-11 mbar*liter/s/cm^2; no degradation over time (2 years) has been found. Suitability for baking has been found to depend on the CFRP production process, presumably on the temperature of the autoclave curing. Together with other unique properties of CuCFRP such as low weight and being nearly non-magnetic, this makes it an ideal material for many high-end vacuum applications.

  17. Copper coated carbon fiber reinforced plastics for high and ultra high vacuum applications

    CERN Document Server

    Burri, F; Feusi, P; Henneck, R; Kirch, K; Lauss, B; Ruettimann, P; Schmidt-Wellenburg, P; Schnabel, A; Voigt, J; Zenner, J; Zsigmond, G

    2013-01-01

    We have used copper-coated carbon fiber reinforced plastic (CuCFRP) for the construction of high and ultra-high vacuum recipients. The vacuum performance is found to be comparable to typical stainless steel used for this purpose. In test recipients we have reached pressures of 2E-8 mbar and measured a desorption rate of 1E-11 mbar*liter/s/cm^2; no degradation over time (2 years) has been found. Suitability for baking has been found to depend on the CFRP production process, presumably on the temperature of the autoclave curing. Together with other unique properties of CuCFRP such as low weight and being nearly non-magnetic, this makes it an ideal material for many high-end vacuum applications.

  18. Post-treatment-free synthesis of highly mesoporous carbon for high-performance supercapacitor in aqueous electrolytes

    Science.gov (United States)

    Li, Wenqi; Liu, Simin; Pan, Ning; Zeng, Fanjun; Liu, Yingliang; Zheng, Mingtao; Liang, Yeru

    2017-07-01

    Exploring well-defined pore structure with high porosity has been a long-pursued goal for the development of porous carbon as high-performance supercapacitor electrodes. The pursuit of high surface area while maintaining uniform pore size remains a formidable challenge because their current template-directed synthetic processes are quite complex and time consuming. Here, we report herein a facile and post-treatment-free approach for synthesis of carbon materials with simultaneously high surface area and uniform mesopore size. The key to this preparation strategy is utilization of polytetrafluoroethylene that can in-situ generate hydrofluoric acid to etch out the silica templates during carbonization process. This strategy not only reduces synthesis procedure by combining post-silica-removal and carbonization in a single step, but also eliminates the direct usage of hazardous hydrofluoric acid or corrosive sodium hydroxide. The as-synthesized disordered mesoporous carbon presents higher Langmuir surface area (3257 m2 g-1), Brunauer-Emmett-Teller surface area (2302 m2 g-1) and mesopore rate (99.6%) when compared to traditional mesoporous carbon. With combination of high surface area and uniform mesopore size, the mesoporous carbon exhibits attractive capacitive properties in aqueous electrolytes, including large capacitance of 201 F g-1, high energy density of 28.3 Wh kg-1 and excellent cycling stability.

  19. Very-high-strength (60-GPa) carbon nanotube fiber design based on molecular dynamics simulations

    Science.gov (United States)

    Cornwell, Charles F.; Welch, Charles R.

    2011-05-01

    The mechanical properties of carbon nanotubes such as low density, high stiffness, and exceptional strength make them ideal candidates for reinforcement material in a wide range of high-performance composites. Molecular dynamics simulations are used to predict the tensile response of fibers composed of aligned carbon nanotubes with intermolecular bonds of interstitial carbon atoms. The effects of bond density and carbon nanotube length distribution on fiber strength and stiffness are investigated. The interstitial carbon bonds significantly increase load transfer between the carbon nanotubes over that obtained with van der Waals forces. The simulation results indicate that fibers with tensile strengths to 60 GPa could be produced by employing interstitial cross-link atoms. The elastic modulus of the fibers is also increased by the bonds.

  20. Targeted carbon conservation at national scales with high-resolution monitoring.

    Science.gov (United States)

    Asner, Gregory P; Knapp, David E; Martin, Roberta E; Tupayachi, Raul; Anderson, Christopher B; Mascaro, Joseph; Sinca, Felipe; Chadwick, K Dana; Higgins, Mark; Farfan, William; Llactayo, William; Silman, Miles R

    2014-11-25

    Terrestrial carbon conservation can provide critical environmental, social, and climate benefits. Yet, the geographically complex mosaic of threats to, and opportunities for, conserving carbon in landscapes remain largely unresolved at national scales. Using a new high-resolution carbon mapping approach applied to Perú, a megadiverse country undergoing rapid land use change, we found that at least 0.8 Pg of aboveground carbon stocks are at imminent risk of emission from land use activities. Map-based information on the natural controls over carbon density, as well as current ecosystem threats and protections, revealed three biogeographically explicit strategies that fully offset forthcoming land-use emissions. High-resolution carbon mapping affords targeted interventions to reduce greenhouse gas emissions in rapidly developing tropical nations.

  1. High Central Aortic Rather than Brachial Blood Pressure is Associated with Carotid Wall Remodeling and Increased Arterial Stiffness in Childhood.

    Science.gov (United States)

    Peluso, Gonzalo; García-Espinosa, Victoria; Curcio, Santiago; Marota, Marco; Castro, Juan; Chiesa, Pedro; Giachetto, Gustavo; Bia, Daniel; Zócalo, Yanina

    2017-03-01

    In adults, central blood pressure (cBP) is reported to associate target organ damages (TODs) rather than peripheral blood pressure (pBP). However, data regarding the association of pre-clinical TODs with cBP and pBP in pediatric populations are scarce. To evaluate in children and adolescents the importance of cBP and pBP levels, in terms of their association with hemodynamic and vascular changes. 315 subjects [age (mean/range) 12/8-18 years] were included. pBP (oscillometry, Omron-HEM433INT and Mobil-O-Graph), cBP levels and waveforms (oscillometry, Mobil-O-Graph; applanation tonometry, SphygmoCor), aortic wave reflection-related parameters, carotid intima-media thickness (CIMT) and carotid (elastic modulus, stiffness-index) and aortic stiffness (carotid-femoral pulse wave velocity, PWV). Four groups were defined considering pBP and cBP percentiles (th): cBP ≥90th, cBP blood pressure (cBP or pBP). Subgroups were matched for anthropometric and cardiovascular risk factors (propensity matching-score). Subjects with high cBP showed a worse cardiovascular risk profile in addition to worse peripheral hemodynamic conditions. The CIMT, carotid and aortic stiffness levels were also higher in those subjects. CIMT and carotid stiffness remained statistically higher when subjects were matched for pBP and other cardiovascular risk factors. There were no differences in arterial properties when subjects were analyzed (compared) considering similar pBP levels, during normal and high cBP conditions. Compared with pBP, the cBP levels show a greater association with vascular alterations (high CIMT and arterial stiffness), in children and adolescents.

  2. A novel mouse model of high flow-induced pulmonary hypertension-surgically induced by right pulmonary artery ligation.

    Science.gov (United States)

    Zhang, Anchen; Wang, Hongfei; Wang, Shengwei; Huang, Xiaofan; Ye, Ping; Du, Xinling; Xia, Jiahong

    2017-02-01

    This study sought to establish a new model of high-flow pulmonary hypertension (PH) in mice. This model may be useful for studies seeking to reduce the pulmonary vascular resistance and delay the development of PH caused by congenital heart disease. The right pulmonary artery was ligated via a right posterolateral thoracotomy. Pulmonary hemodynamics was evaluated by right heart catheterization immediately after ligation and at 2, 4, 8, and 12 wk postoperatively. The right ventricle (RV) and the left ventricle (LV) with septum (S) were weighed to calculate the RV/(LV + S) ratio as an index of right ventricular hypertrophy. Morphologic changes in the left lungs were analyzed, and percentages of muscularized pulmonary vessels were assessed by hematoxylin and eosin, elastica van Gieson and alpha-smooth muscle actin staining. All the study data were compared with data from a model of PH generated by hypoxic stimulation. A pulmonary hypertensive state was successfully induced by 2 wk after surgery. However, the morphologic analysis demonstrated that pulmonary vascular muscularization, as evaluated using right ventricular systolic pressure and RV/(LV + S), was not significantly increased until 4 wk postoperatively. When mice from the new model and the hypoxic model were compared, no significant differences were observed in any of the evaluated indices. High-flow PH can be induced within 4 wk after ligation of the right pulmonary artery, which is easily performed in mice. Such mice can be used as a model of high-flow PH. Copyright © 2016 Elsevier Inc. All rights reserved.

  3. High Volume Fraction Carbon Nanotube Composites for Aerospace Applications

    Science.gov (United States)

    Siochi, E. J.; Kim, J.-W.; Sauti, G.; Cano, R. J.; Wincheski, R. A.; Ratcliffe, J. G.; Czabaj, M.

    2016-01-01

    Reported mechanical properties of carbon nanotubes (CNTs) at the nanoscale suggest their potential to enable significantly lighter structures of interest for space applications. However, their utility depends on the retention of these properties in bulk material formats that permit practical fabrication of large structures. This presentation summarizes recent progress made to produce carbon nanotube composites with specific tensile properties that begin to rival those of carbon fiber reinforced polymer composites. CNT content in these nanocomposites was greater than 70% by weight. Tested nanocomposite specimens were fabricated from kilometers or tens of square meters of CNT, depending on the starting material format. Processing methods to yield these results, and characterization and testing to evaluate the performance of these composites will be discussed. The final objective is the demonstration of a CNT composite overwrapped pressure vessel to be flight tested in the Fall of 2016.

  4. Nickel clusters embedded in carbon nanotubes as high performance magnets

    Science.gov (United States)

    Shiozawa, Hidetsugu; Briones-Leon, Antonio; Domanov, Oleg; Zechner, Georg; Sato, Yuta; Suenaga, Kazu; Saito, Takeshi; Eisterer, Michael; Weschke, Eugen; Lang, Wolfgang; Peterlik, Herwig; Pichler, Thomas

    2015-10-01

    Ensembles of fcc nickel nanowires have been synthesized with defined mean sizes in the interior of single-wall carbon nanotubes. The method allows the intrinsic nature of single-domain magnets to emerge with large coercivity as their size becomes as small as the exchange length of nickel. By means of X-ray magnetic circular dichroism we probe electronic interactions at nickel-carbon interfaces where nickel exhibit no hysteresis and size-dependent spin magnetic moment. A manifestation of the interacting two subsystems on a bulk scale is traced in the nanotube’s magnetoresistance as explained within the framework of weak localization.

  5. Laser-engraved carbon nanotube paper for instilling high sensitivity, high stretchability, and high linearity in strain sensors

    KAUST Repository

    Xin, Yangyang

    2017-06-29

    There is an increasing demand for strain sensors with high sensitivity and high stretchability for new applications such as robotics or wearable electronics. However, for the available technologies, the sensitivity of the sensors varies widely. These sensors are also highly nonlinear, making reliable measurement challenging. Here we introduce a new family of sensors composed of a laser-engraved carbon nanotube paper embedded in an elastomer. A roll-to-roll pressing of these sensors activates a pre-defined fragmentation process, which results in a well-controlled, fragmented microstructure. Such sensors are reproducible and durable and can attain ultrahigh sensitivity and high stretchability (with a gauge factor of over 4.2 × 10(4) at 150% strain). Moreover, they can attain high linearity from 0% to 15% and from 22% to 150% strain. They are good candidates for stretchable electronic applications that require high sensitivity and linearity at large strains.

  6. Circulating Concentrations of Adipocytokines and Their Receptors in the Isolated Corpus Cavernosum and Femoral Artery from Trained Rats on a High-Fat Diet.

    Science.gov (United States)

    Sponton, Amanda C S; Silva, Fábio H; Araujo, Hygor N; Valgas da Silva, Carmem P; de Moraes, Camila; Antunes, Edson; Zanesco, Angelina; Delbin, Maria A

    2017-01-01

    The aim of the present study was to evaluate different signaling pathways by which exercise training would interfere in endothelial function in obesity. Therefore, we examined adipocytokine levels and their receptors in the corpus cavernosum and femoral artery from trained rats on a high-fat diet. Functional experiments were performed in control sedentary and trained rats, and sedentary (h-SD) and trained male Wistar rats on a high-fat diet (h-TR). Nitric oxide (NO) and reactive oxygen species (ROS) were evaluated in vascular tissue. Circulating adipocytokines and their receptors were analyzed. In the h-SD group, the maximal responses to acetylcholine (ACh) were reduced in the femoral artery and corpus cavernosum as well as the electrical field stimulation, accompanied by an increase in circulating insulin, leptin, TNF-α, MCP-1, and PAI-1. Downregulation of ObR protein expression in the femoral artery was observed without alterations in AdipoR1 and TNFR1 in both preparations. A positive effect was observed in the h-TR group regarding the relaxation response to ACh and circulating adipocytokines, resulting in increased NO production and reduced ROS generation. Exercise restored the ObR protein expression only in the femoral artery. Aerobic exercise training ameliorated the inflammatory adipocytokines and restored the relaxation responses in the corpus cavernosum and femoral artery in rats on a high-fat diet. © 2017 S. Karger AG, Basel.

  7. Biomass Waste Inspired Highly Porous Carbon for High Performance Lithium/Sulfur Batteries.

    Science.gov (United States)

    Zhao, Yan; Ren, Jun; Tan, Taizhe; Babaa, Moulay-Rachid; Bakenov, Zhumabay; Liu, Ning; Zhang, Yongguang

    2017-09-06

    The synthesis of highly porous carbon (HPC) materials from poplar catkin by KOH chemical activation and hydrothermal carbonization as a conductive additive to a lithium-sulfur cathode is reported. Elemental sulfur was composited with as-prepared HPC through a melt diffusion method to form a S/HPC nanocomposite. Structure and morphology characterization revealed a hierarchically sponge-like structure of HPC with high pore volume (0.62 cm³∙g (−1) ) and large specific surface area (1261.7 m²∙g (−1) ). When tested in Li/S batteries, the resulting compound demonstrated excellent cycling stability, delivering a second-specific capacity of 1154 mAh∙g (−1) as well as presenting 74% retention of value after 100 cycles at 0.1 C. Therefore, the porous structure of HPC plays an important role in enhancing electrochemical properties, which provides conditions for effective charge transfer and effective trapping of soluble polysulfide intermediates, and remarkably improves the electrochemical performance of S/HPC composite cathodes.

  8. Is carotid artery evaluation necessary for primary prevention in asymptomatic high-risk patients without atherosclerotic cardiovascular disease?

    Directory of Open Access Journals (Sweden)

    Kim GH

    2015-07-01

    Full Text Available GeeHee Kim,1 Ho-Joong Youn,2 Yun-Seok Choi,2 Hae Ok Jung,2 Wook Sung Chung,2 Chul-Min Kim1 1Department of Internal Medicine, St Vincent’s Hospital, The Catholic University of Korea, Suwon, 2Division of Cardiology, Department of Internal Medicine, School of Medicine, The Catholic University of Korea, Seoul, Republic of Korea Objective: Routine measurement of the carotid intima–media thickness is not recommended in recent clinical practice guidelines for risk assessment of the first atherosclerotic cardiovascular disease (ASCVD event (the definition of which includes acute coronary syndromes, a history of myocardial infarction, stable or unstable angina, coronary or other arterial revascularization, stroke, transient ischemic attack, or peripheral arterial disease presumed to be of atherosclerotic origin. The aim of the present study was to elucidate the role of carotid artery evaluation for primary prevention of ASCVD in asymptomatic high-risk patients visiting a teaching hospital.Methods: Eight hundred seventy-three patients (487 male [55.8%], mean age 59.4±11.5 years who were statin-naive and without ASCVD, which was proven by coronary angiography or coronary CT angiography, were enrolled in this study. The patients underwent carotid scanning in the Medical Department of St Mary’s Hospital from September 2003 to March 2009. ASCVD outcomes were evaluated for median follow-up of 1,402 days.Results: A total of 119 participants experienced ASCVD events. In multivariate Cox regression analysis, age (hazard ratio [HR] =1.026, 95% confidence interval [CI] =1.002–1.050, P=0.033, history of smoking (HR =1.751, 95% CI =1.089–2.815, P=0.021, statin therapy (HR =0.388, 95% CI =0.205–0.734, P=0.004, and carotid plaques (HR =1.556, 95% CI =1.009–2.400, P=0.045 were associated with ASCVD events. In middle-aged group (45≤ age <65, n=473, history of smoking (HR =1.995, 95% CI =1.142–3.485, P=0.015, statin therapy (HR =0.320, 95% CI =0.131

  9. Microstructures and Hardness/Wear Performance of High-Carbon Stellite Alloys Containing Molybdenum

    Science.gov (United States)

    Liu, Rong; Yao, J. H.; Zhang, Q. L.; Yao, M. X.; Collier, Rachel

    2015-12-01

    Conventional high-carbon Stellite alloys contain a certain amount of tungsten which mainly serves to provide strengthening to the solid solution matrix. These alloys are designed for combating severe wear. High-carbon molybdenum-containing Stellite alloys are newly developed 700 series of Stellite family, with molybdenum replacing tungsten, which are particularly employed in severe wear condition with corrosion also involved. Three high-carbon Stellite alloys, designated as Stellite 706, Stellite 712, and Stellite 720, with different carbon and molybdenum contents, are studied experimentally in this research, focusing on microstructure and phases, hardness, and wear resistance, using SEM/EDX/XRD techniques, a Rockwell hardness tester, and a pin-on-disk tribometer. It is found that both carbon and molybdenum contents influence the microstructures of these alloys significantly. The former determines the volume fraction of carbides in the alloys, and the latter governs the amount of molybdenum-rich carbides precipitated in the alloys. The hardness and wear resistance of these alloys are increased with the carbide volume fraction. However, with the same or similar carbon content, high-carbon CoCrMo Stellite alloys exhibit worse wear resistance than high-carbon CoCrW Stellite alloys.

  10. Highly porous activated carbons from resource-recovered Leucaena leucocephala wood as capacitive deionization electrodes.

    Science.gov (United States)

    Hou, Chia-Hung; Liu, Nei-Ling; Hsi, Hsing-Cheng

    2015-12-01

    Highly porous activated carbons were resource-recovered from Leucaena leucocephala (Lam.) de Wit. wood through combined chemical and physical activation (i.e., KOH etching followed by CO2 activation). This invasive species, which has severely damaged the ecological economics of Taiwan, was used as the precursor for producing high-quality carbonaceous electrodes for capacitive deionization (CDI). Carbonization and activation conditions strongly influenced the structure of chars and activated carbons. The total surface area and pore volume of activated carbons increased with increasing KOH/char ratio and activation time. Overgasification induced a substantial amount of mesopores in the activated carbons. In addition, the electrochemical properties and CDI electrosorptive performance of the activated carbons were evaluated; cyclic voltammetry and galvanostatic charge/discharge measurements revealed a typical capacitive behavior and electrical double layer formation, confirming ion electrosorption in the porous structure. The activated-carbon electrode, which possessed high surface area and both mesopores and micropores, exhibited improved capacitor characteristics and high electrosorptive performance. Highly porous activated carbons derived from waste L. leucocephala were demonstrated to be suitable CDI electrode materials.

  11. High preoperative monocyte count/high-density lipoprotein ratio is associated with postoperative atrial fibrillation and mortality in coronary artery bypass grafting.

    Science.gov (United States)

    Saskin, Hüseyin; Serhan Ozcan, Kazim; Yilmaz, Seyhan

    2017-03-01

    The monocyte to high-density lipoprotein ratio has recently emerged as an indicator of inflammation and oxidative stress. The aim of this study was to evaluate the association of the monocyte to high-density lipoprotein ratio with postoperative atrial fibrillation and mortality in coronary artery bypass grafting. Six hundred and sixty-two patients who were in sinus rhythm preoperatively and who had isolated coronary artery bypass grafting were retrospectively included in the study. Patients who had atrial fibrillation in the early postoperative period were enrolled in group 1 ( n  = 153); patients who remained in sinus rhythm in the early postoperative period were included in group 2 ( n  = 509). The clinical and demographic data of the patients, biochemical and complete blood count parameters, preoperative monocyte count/high-density lipoprotein cholesterol ratio, and operative and postoperative data were recorded. Preoperative monocyte counts ( P  = 0.0001), monocyte count/high-density lipoprotein cholesterol ratio ( P = 0.0001) and C-reactive protein levels ( P  = 0.0001) were significantly increased in group 1. In the first month, 8 patients in group 1 (5.2%) and 5 patients in group 2 (1.0%) died, which was statistically significant ( P  = 0.003). In univariate and multivariate logistic regression analyses, an elevated preoperative monocyte count/high-density lipoprotein cholesterol ratio ( P  = 0.03) and C-reactive protein levels ( P  = 0.0001) were predictors of postoperative atrial fibrillation. Preoperative monocyte counts ( P  = 0.001), monocyte count/high-density lipoprotein cholesterol ratio ( P  = 0.0001) and the use of inotropic support ( P  = 0.0001) were also predictors of mortality in the early postoperative period. We have observed that high preoperative monocyte count/ high-density lipoprotein ratio was associated with postoperative atrial fibrillation and mortality after coronary artery bypass grafting

  12. Prevalência de pressão arterial elevada em crianças e adolescentes: revisão sistemática The prevalence of high arterial blood pressure in children and adolescents: a systematic review

    Directory of Open Access Journals (Sweden)

    Diego Giulliano Destro Christofaro

    2011-12-01

    Full Text Available OBJETIVOS: identificar as prevalências de pressão arterial elevada em crianças e adolescentes em estudos publicados nos últimos 30 anos. MÉTODOS: foi realizada uma busca nas seguintesbases de dados: Medline/PubMed, Lilacs, Web ofScience, Embase e Scielo entre os anos de 1980 e 2009. Foram incluídos estudos originais de prevalência de pressão arterial elevada ou hipertensão com tamanho amostral superior a 500sujeitos. RESULTADOS: a prevalência de pressão arterial elevada em crianças e adolescentes de 4 a 20 anos variou de 0,46% a 20,6%. As menores prevalências de pressão arterial elevada foram detectadas nos estudos em que a maior parte da amostra foi composta por crianças de 4 a 7 anos. Os protocolos mais utilizados na avaliação da pressão arterial foram o da Task Force e o do National High Blood Pressure Education Program. Ao todo 52,4% dos estudos utilizaram o método auscultatório para verificar a medida de pressão arterial e 47,6%, o método oscilométrico. CONCLUSÕES: apesar da grande discrepância dos valores de prevalência encontrados, ressalta-se ocrescimento da prevalência de pressão arterial elevada na população de crianças e adolescentes de diversas partes do mundo.OBJECTIVES: to identify the prevalence of high blood pressure in children and adolescents in studiespublished in the past 30 years. METHODS: a search was carried out in the Medline/PubMed, Lilacs, Web of Science, Embase and Scielo databases for articles published between 1980 and 2009. Articles were included if they were original studies of the prevalence of high arterial blood pressure or hypertension in a sample of more than 500 subjects. RESULTS: the prevalence of high blood pressure (in individuals aged between 4 and 20 years varied from 0.46% to 20.6%. The lower prevalence of high blood pressure was found in studies where the majority ofthe sample was aged between 4 and 7 years. Theprotocols most commonly used for evaluation of blood pressure

  13. Dry-cleaning with high-pressure carbon dioxide

    NARCIS (Netherlands)

    Van Roosmalen, M.J.E.

    2003-01-01

    Dry-cleaning is a process for removing soils and stains from fabrics and garments which uses a non-aqueous solvent with detergent added. The currently most used dry-cleaning solvent is perchloroethylene (PER), which is toxic, environmentally harmful and suspected to be carcinogenic. Carbon dioxide

  14. Carotid artery atherosclerosis in a Mexico City population with high carbohydrate intake.

    Science.gov (United States)

    González-Villalpando, C; Stern, M P; Rivera Martínez, D; Arredondo Pérez, B; Martínez Diaz, S; Haffner, S

    1995-01-01

    We present the results of a population based survey designed to estimate the prevalence and clinical characteristics of carotid artery atherosclerosis (CAS) diagnosed using vascular ultrasonography (VUS) in a low income area of Mexico City encompassing six neighborhoods that we previously studied. We attempted to locate all the non-diabetic participants of the first two neighborhoods (n = 834) and all diabetics from the six neighborhoods (n = 304). We located 1078 (94.7%) participants and examined 770 (71.4%). All study subjects were men and non-pregnant women between 35-64 years of age and had standardized VUS protocol. In men, the prevalence of CAS was 16.29%, in women the prevalence was 12.3%. CAS was significantly associated in both sexes to age (p < 0.001) and systolic blood pressure (p < 0.001). The ratio of the subscapular to triceps skinfolds was significantly higher in men with CAS (p < 0.04). In women, fasting glucose was higher in subjects with CAS (p < 0.04). The lipid profile was similar in men with and without CAS. However, women with CAS had significantly higher total cholesterol (p < 0.001), LDL cholesterol (p < 0.002), VLDL cholesterol (p < 0.092) and mean TG (p < 0.033). The percent of patients with hypertension, tobacco use, myocardial infarction and diabetic retinopathy of any degree was significantly higher in the subjects with CAS. CAS of any degree was observed in 12.4% of the non-diabetic population and 18.13% of the diabetics.(ABSTRACT TRUNCATED AT 250 WORDS)

  15. A comparison of high-dose and low-dose tranexamic acid antifibrinolytic protocols for primary coronary artery bypass surgery

    Directory of Open Access Journals (Sweden)

    Stephen M McHugh

    2016-01-01

    Full Text Available Background and Aims: Tranexamic acid (TA is used for prophylactic antifibrinolysis in coronary artery bypass surgeries to reduce bleeding. We evaluated the efficacy of two different doses of TA for prophylactic antifibrinolysis in patients undergoing primary coronary artery bypass grafting (CABG surgery in this retrospective cohort study at a tertiary care referral centre. Methods: One-hundred eighty-four patients who underwent primary CABG with cardiopulmonary bypass (CPB via sternotomy between January 2009 and June 2011 were evaluated. Pre-operative patient characteristics, intraoperative data, post-operative bleeding, transfusions, organ dysfunction and 30-day mortality were compared between high-dose TA (30 mg/kg loading dose followed by infusion of 15 mg/kg/h until the end of surgery along with 2 mg/kg priming dose in the bypass circuit and low-dose TA (15 mg/kg loading dose followed by infusion of 6 mg/kg/h until the end of surgery along with 1 mg/kg priming dose in the bypass circuit groups. Univariate comparative analysis of all categorical and continuous variables was performed between the two groups by appropriate statistical tests. Linear and logistic regression analyses were performed to control for the effect of confounding on the outcome variables. Results: Chest tube output, perioperative transfusion of blood products and incidence of re-exploration for bleeding did not differ significantly (P> 0.05 between groups. Post-operative complications and 30-day mortality were comparable between the groups. The presence of cardiogenic shock and increased pre-operative creatinine were found to be associated with increased chest tube output on the post-operative day 2 by multivariable linear regression model. Conclusions: Low-dose TA protocol is as effective as high-dose protocol for antifibrinolysis in patients undergoing primary CABG with CPB.

  16. Elevated pulmonary artery pressure and brain natriuretic peptide in high altitude pulmonary edema susceptible non-mountaineers

    Science.gov (United States)

    Gupta, Rajinder K.; Himashree, G.; Singh, Krishan; Soree, Poonam; Desiraju, Koundinya; Agrawal, Anurag; Ghosh, Dishari; Dass, Deepak; Reddy, Prassana K.; Panjwani, Usha; Singh, Shashi Bala

    2016-01-01

    Exaggerated pulmonary pressor response to hypoxia is a pathgonomic feature observed in high altitude pulmonary edema (HAPE) susceptible mountaineers. It was investigated whether measurement of basal pulmonary artery pressure (Ppa) and brain natriuretic peptide (BNP) could improve identification of HAPE susceptible subjects in a non-mountaineer population. We studied BNP levels, baseline hemodynamics and the response to hypoxia (FIo2 = 0.12 for 30 min duration at sea level) in 11 HAPE resistant (no past history of HAPE, Control) and 11 HAPE susceptible (past history of HAPE, HAPE-S) subjects. Baseline Ppa (19.31 ± 3.63 vs 15.68 ± 2.79 mm Hg, p < 0.05) and plasma BNP levels (52.39 ± 32.9 vs 15.05 ± 9.6 pg/ml, p < 0.05) were high and stroke volume was less (p < 0.05) in HAPE-S subjects compared to control. Acute hypoxia produced an exaggerated increase in heart rate (p < 0.05), mean arterial pressure (p < 0.05) and Ppa (28.2 ± 5.8 vs 19.33 ± 3.74 mm Hg, p < 0.05) and fall in peripheral oxygen saturation (p < 0.05) in HAPE-S compared to control. Receiver operating characteristic (ROC) curves showed that Ppa response to acute hypoxia was the best variable to identify HAPE susceptibility (AUC 0.92) but BNP levels provided comparable information (AUC 0.85). BNP levels are easy to determine and may represent an important marker for the determination of HAPE susceptibility. PMID:26892302

  17. Nanostructured water and carbon dioxide inside collapsing carbon nanotubes at high pressure.

    Science.gov (United States)

    Cui, Wenwen; Cerqueira, Tiago F T; Botti, Silvana; Marques, Miguel A L; San-Miguel, Alfonso

    2016-07-20

    We present simulations of the collapse under hydrostatic pressure of carbon nanotubes containing either water or carbon dioxide. We show that the molecules inside the tube alter the dynamics of the collapse process, providing either mechanical support and increasing the collapse pressure, or reducing mechanical stability. At the same time the nanotube acts as a nanoanvil, and the confinement leads to the nanostructuring of the molecules inside the collapsed tube. In this way, depending on the pressure and on the concentration of water or carbon dioxide inside the nanotube, we observe the formation of 1D molecular chains, 2D nanoribbons, and even molecular single and multi-walled nanotubes. The structure of the encapsulated molecules correlates with the mechanical response of the nanotube, opening up opportunities for the development of new devices or composite materials. Our analysis is quite general and it can be extended to other molecules in carbon nanotube nanoanvils, providing a strategy to obtain a variety of nano-objects with controlled features.

  18. Supraaortic arteries: contrast-enhanced MR angiography at 3.0 T--highly accelerated parallel acquisition for improved spatial resolution over an extended field of view.

    Science.gov (United States)

    Nael, Kambiz; Villablanca, J Pablo; Pope, Whitney B; McNamara, Thomas O; Laub, Gerhard; Finn, J Paul

    2007-02-01

    To prospectively use 3.0-T breath-hold high-spatial-resolution contrast material-enhanced magnetic resonance (MR) angiography with highly accelerated parallel acquisition to image the supraaortic arteries of patients suspected of having arterial occlusive disease. Institutional review board approval and written informed consent were obtained for this HIPAA-compliant study. Eighty patients (44 men, 36 women; age range, 44-90 years) underwent contrast-enhanced MR angiography of the head and neck at 3.0 T with an eight-channel neurovascular array coil. By applying a generalized autocalibrating partially parallel acquisition algorithm with an acceleration factor of four, high-spatial-resolution (0.7 x 0.7 x 0.9 mm = 0.44-mm(3) voxels) three-dimensional contrast-enhanced MR angiography was performed during a 20-second breath hold. Two neuroradiologists evaluated vascular image quality and arterial stenoses. Interobserver variability was tested with the kappa coefficient. Quantitation of stenosis at MR angiography was compared with that at digital subtraction angiography (DSA) (n = 13) and computed tomographic (CT) angiography (n = 12) with Spearman rank correlation coefficient (R(s)). Arterial stenoses were detected with contrast-enhanced MR angiography in 208 (reader 1) and 218 (reader 2) segments, with excellent interobserver agreement (kappa = 0.80). There was a significant correlation between contrast-enhanced MR angiography and CT angiography (R(s) = 0.95, reader 1; R(s) = 0.87, reader 2) and between contrast-enhanced MR angiography and DSA (R(s) = 0.94, reader 1; R(s) = 0.92, reader 2) for the degree of stenosis. Sensitivity and specificity of contrast-enhanced MR angiography for detection of arterial stenoses greater than 50% were 94% and 98% for reader 1 and 100% and 98% for reader 2, with DSA as the standard of reference. Vascular image quality was sufficient for diagnosis or excellent for 97% of arterial segments evaluated. By using highly accelerated parallel

  19. Copper Decoration of Carbon Nanotubes and High Resolution Electron Microscopy

    Science.gov (United States)

    Probst, Camille

    A new process of decorating carbon nanotubes with copper was developed for the fabrication of nanocomposite aluminum-nanotubes. The process consists of three stages: oxidation, activation and electroless copper plating on the nanotubes. The oxidation step was required to create chemical function on the nanotubes, essential for the activation step. Then, catalytic nanoparticles of tin-palladium were deposited on the tubes. Finally, during the electroless copper plating, copper particles with a size between 20 and 60 nm were uniformly deposited on the nanotubes surface. The reproducibility of the process was shown by using another type of carbon nanotube. The fabrication of nanocomposites aluminum-nanotubes was tested by aluminum vacuum infiltration. Although the infiltration of carbon nanotubes did not produce the expected results, an interesting electron microscopy sample was discovered during the process development: the activated carbon nanotubes. Secondly, scanning transmitted electron microscopy (STEM) imaging in SEM was analysed. The images were obtained with a new detector on the field emission scanning electron microscope (Hitachi S-4700). Various parameters were analysed with the use of two different samples: the activated carbon nanotubes (previously obtained) and gold-palladium nanodeposits. Influences of working distance, accelerating voltage or sample used on the spatial resolution of images obtained with SMART (Scanning Microscope Assessment and Resolution Testing) were analysed. An optimum working distance for the best spatial resolution related to the sample analysed was found for the imaging in STEM mode. Finally, relation between probe size and spatial resolution of backscattered electrons (BSE) images was studied. An image synthesis method was developed to generate the BSE images from backscattered electrons coefficients obtained with CASINO software. Spatial resolution of images was determined using SMART. The analysis shown that using a probe

  20. Identification of Relevant Work Parameters of Ladle Furnace While Melting the High Ductility Steel and High-Carbon Steel

    Directory of Open Access Journals (Sweden)

    Warzecha M.

    2016-03-01

    Full Text Available In the present paper, secondary metallurgical treatment in ladle furnace during smelting the high carbon steel and steel with improved ductility for cold-deforming, under industrial conditions were analyzed.

  1. Carbon Nanofibers Modified Graphite Felt for High Performance Anode in High Substrate Concentration Microbial Fuel Cells

    Directory of Open Access Journals (Sweden)

    Youliang Shen

    2014-01-01

    Full Text Available Carbon nanofibers modified graphite fibers (CNFs/GF composite electrode was prepared for anode in high substrate concentration microbial fuel cells. Electrochemical tests showed that the CNFs/GF anode generated a peak current density of 2.42 mA cm−2 at a low acetate concentration of 20 mM, which was 54% higher than that from bare GF. Increase of the acetate concentration to 80 mM, in which the peak current density of the CNFs/GF anode greatly increased and was up to 3.57 mA cm−2, was seven times as that of GF anode. Morphology characterization revealed that the biofilms in the CNFs/GF anode were much denser than those in the bare GF. This result revealed that the nanostructure in the anode not only enhanced current generation but also could tolerate high substrate concentration.

  2. Carbon cycling and phytoplankton responses within highly-replicated shipboard carbonate chemistry manipulation experiments conducted around Northwest European Shelf Seas

    Science.gov (United States)

    Richier, S.; Achterberg, E. P.; Dumousseaud, C.; Poulton, A. J.; Suggett, D. J.; Tyrrell, T.; Zubkov, M. V.; Moore, C. M.

    2014-03-01

    The ongoing oceanic uptake of anthropogenic carbon dioxide (CO2) is significantly altering the carbonate chemistry of seawater, a phenomenon referred to as ocean acidification. Experimental manipulations have been increasingly used to gauge how continued ocean acidification will potentially impact marine ecosystems and their associated biogeochemical cycles in the future; however, results amongst studies, particularly when performed on natural communities, are highly variable, which in part likely reflects inconsistencies in experimental approach. To investigate the potential for identification of more generic responses and greater experimentally reproducibility, we devised and implemented a series of highly replicated (n = 8), short term (2-4 days) multi-level (≥ 4 conditions) carbonate chemistry/nutrient manipulation experiments on a range of natural microbial communities sampled in Northwest European shelf seas. Carbonate chemistry manipulations and resulting biological responses were found to be highly reproducible within individual experiments and to a lesser extent between geographically different experiments. Statistically robust reproducible physiological responses of phytoplankton to increasing pCO2, characterized by a suppression of net growth for small sized cells (ocean.

  3. Influences of carbon and silicon on blister formation in scale surface during high temperature oxidation of carbon steels

    Science.gov (United States)

    Kim, Deuk-Jung; Lee, Jae-Sang; Koo, Yang-Mo

    2017-07-01

    The in-situ blistering phenomena of the scale `surface' was investigated on three carbon steels with respect to carbon and silicon concentrations, such as 0.05 wt%C, 0.2 wt%C, and 0.2 wt%C-0.2 wt%Si. The oxidation and blistering kinetics and blister area fraction during high temperature oxidation were analyzed. The average thickness of the surface scale by oxidation during isothermal holding from 800 to 1200 °C in dry air was observed to decrease when the amount of carbon increased and/or when Si was inserted additionally. Thus, the blistering behavior depended primarily on a change in oxidation temperature ( T ox ) as well as amounts of carbon and silicon in the matrix. It is also revealed that such blister formation would be triggered by growth of internal stress and active generations of CO and/or CO2 gases at the interface between the scale and matrix since carbon would result in an increase in the blister formation by generating CO and/or CO2 gas. In addition, silicon might play an important role in preventing the blister formation at T ox below 900 °C by reducing the thickness of the surface scale whilst silicon might enhance the blister formation by means of the appreciable micro-void formation in the scale layer at T ox higher 900 °C.

  4. Scratch-resistant, highly conductive, and high-strength carbon nanotube-based composite yarns.

    Science.gov (United States)

    Liu, Kai; Sun, Yinghui; Lin, Xiaoyang; Zhou, Ruifeng; Wang, Jiaping; Fan, Shoushan; Jiang, Kaili

    2010-10-26

    High-strength and conductive carbon nanotube (CNT) yarns are very attractive in many potential applications. However, there is a difficulty when simultaneously enhancing the strength and conductivity of CNT yarns. Adding some polymers into CNT yarns to enhance their strength will decrease their conductivity, while treating them in acid or coating them with metal nanoparticles to enhance their conductivity will reduce their strength. To overcome this difficulty, here we report a method to make high-strength and highly conductive CNT-based composite yarns by using a continuous superaligned CNT (SACNT) yarn as a conductive framework and then inserting polyvinyl alcohol (PVA) into the intertube spaces of the framework through PVA/dimethyl sulphoxide solution to enhance the strength of yarns. The as-produced CNT/PVA composite yarns possess very high tensile strengths up to 2.0 GPa and Young's moduli more than 120 GPa, much higher than those of the CNT/PVA yarns reported. The electric conductivity of as-produced composite yarns is as high as 9.2 × 10(4) S/m, comparable to HNO(3)-treated or Au nanoparticle-coated CNT yarns. These composite yarns are flexible, lightweight, scratch-resistant, very stable in the lab environment, and resistant to extremely humid ambient and as a result can be woven into high-strength and heatable fabrics, showing potential applications in flexible heaters, bullet-proof vests, radiation protection suits, and spacesuits.

  5. Preparation of Isolated Single-walled Carbon Nanotubes with High Hydrogen Storage Capacity

    Institute of Scientific and Technical Information of China (English)

    张艾飞; 刘吉平; 吕广庶; 刘华

    2006-01-01

    Isolated single-walled carbon nanotubes with high proportion of opening tips were synthesized by using alcohol as carbon source. The mechanism of cutting action of oxygen was proposed to explain its growth. Compared with carbon nanotubes synthesized with benzene as carbon source, their specific surface area was heightened by approximately 2.2 times (from 200.5 to 648 m2/g) and the hydrogen storage capacity was increased by approximately 6.5 times (from 0.95 to 7.17%, ω)which had exceeded DOE energy standard of vehicular hydrogen storage.

  6. Anomalous origin of the coronary artery from the wrong coronary sinus evaluated with computed tomography: ''High-risk'' anatomy and its clinical relevance

    Energy Technology Data Exchange (ETDEWEB)

    Krupinski, Maciej; Urbanczyk-Zawadzka, Malgorzata; Laskowicz, Bartosz; Irzyk, Malgorzata; Banys, Robert; Klimeczek, Piotr [John Paul II Hospital, Department of Radiology and Diagnostic Imaging, Krakow (Poland); Gruszczynska, Katarzyna; Baron, Jan [Medical University of Silesia, Department of Radiology and Nuclear Medicine, Katowice (Poland)

    2014-10-15

    The aim of the study was to assess coronary arteries arising from the wrong coronary sinus, including CT-evaluated high-risk anatomic features, clinical symptoms and cardiac events during follow-up. A total of 7,115 patients scheduled for 64-slice or dual-source cardiac CT were screened for the presence of isolated anomalous origin of the coronary artery from the wrong coronary sinus. Anomalous origin of the coronary artery was found in 54 (0.76 %) patients (29 men, 25 women, mean age 60.9 ± 11.6 years). Sixteen (30 %) patients with abnormal right coronary origin (ARCA) more commonly had a slit-like orifice (15 vs. 3; p < 0.001), intramural course (15 vs. 3; p < 0.001) and interarterial course (11 vs. 0; p < 0.001) than 22 (41 %) and 13 (24 %) individuals with abnormal circumflex artery (ALCx) and left coronary artery (ALCA) origin, respectively. Patients with ALCA presented less frequently with chest pain than subjects with ARCA and ALCx (25 vs. 3; p = 0.03). Patients with ARCA tended to show higher occurrence of cardiac events in the follow-up than individuals with ALCA and ALCx (5 vs. 4; p = NS). High-risk anatomy features are most common in patients with ARCA and these patients also have higher prevalence of chest pain and cardiac events in the follow-up than individuals with ALCA and ALCx. (orig.)

  7. Highly conjugated water soluble CdSe quantum dots to multiwalled carbon nanotubes

    Institute of Scientific and Technical Information of China (English)

    Gui Zheng Zou

    2009-01-01

    Highly conjugated multiwalled carbon nanotube-quantum dot heterojunctions were synthesized by ethylene carbodiimide coupling procedure. The functional multiwalled carbon nanotube with carboxylic groups on sidewall could react with the amino group of L-cysteine capped CdSe quantum dots and then resulted in nanotube-quantum dot heterojunctions. Scanning electron microscopy was used to characterize the heterojunctions.

  8. High Flux Laser Radiation and Residual Gas Interactions with Carbon-Based Structural Materials.

    Science.gov (United States)

    and (111) single crystal faces of Ti reacted with CO. The interest in titanium carbide is based on its importance as a high temperature material...artificial superlattices of titanium carbides and comparing their properties to that of naturally occurring titanium carbide which is a cubic metallic...conductor. Keywords: Carbon Monoxide; Titanium; Carbon; Sodium Chloride; Titanium Carbide .

  9. Dense high-aspect ratio 3D carbon pillars on interdigitated microelectrode arrays

    DEFF Research Database (Denmark)

    Amato, Letizia; Heiskanen, Arto; Hansen, Rasmus

    2015-01-01

    In this work we present high-aspect ratio carbon pillars (1.4 μm in diameter and ∼11 μm in height) on top of interdigitated electrode arrays to be used for electrochemical applications. For this purpose, different types of 2D and 3D pyrolysed carbon structures were fabricated and characterised...

  10. Carbon Nanofiber-Based, High-Frequency, High-Q, Miniaturized Mechanical Resonators

    Science.gov (United States)

    Kaul, Anupama B.; Epp, Larry W.; Bagge, Leif

    2011-01-01

    High Q resonators are a critical component of stable, low-noise communication systems, radar, and precise timing applications such as atomic clocks. In electronic resonators based on Si integrated circuits, resistive losses increase as a result of the continued reduction in device dimensions, which decreases their Q values. On the other hand, due to the mechanical construct of bulk acoustic wave (BAW) and surface acoustic wave (SAW) resonators, such loss mechanisms are absent, enabling higher Q-values for both BAW and SAW resonators compared to their electronic counterparts. The other advantages of mechanical resonators are their inherently higher radiation tolerance, a factor that makes them attractive for NASA s extreme environment planetary missions, for example to the Jovian environments where the radiation doses are at hostile levels. Despite these advantages, both BAW and SAW resonators suffer from low resonant frequencies and they are also physically large, which precludes their integration into miniaturized electronic systems. Because there is a need to move the resonant frequency of oscillators to the order of gigahertz, new technologies and materials are being investigated that will make performance at those frequencies attainable. By moving to nanoscale structures, in this case vertically oriented, cantilevered carbon nanotubes (CNTs), that have larger aspect ratios (length/thickness) and extremely high elastic moduli, it is possible to overcome the two disadvantages of both bulk acoustic wave (BAW) and surface acoustic wave (SAW) resonators. Nano-electro-mechanical systems (NEMS) that utilize high aspect ratio nanomaterials exhibiting high elastic moduli (e.g., carbon-based nanomaterials) benefit from high Qs, operate at high frequency, and have small force constants that translate to high responsivity that results in improved sensitivity, lower power consumption, and im - proved tunablity. NEMS resonators have recently been demonstrated using topdown

  11. Acute arterial occlusion - kidney

    Science.gov (United States)

    Acute renal arterial thrombosis; Renal artery embolism; Acute renal artery occlusion; Embolism - renal artery ... kidney can often result in permanent kidney failure. Acute arterial occlusion of the renal artery can occur after injury or trauma to ...

  12. Increased oxidative stress and severe arterial remodeling induced by permanent high-flow challenge in experimental pulmonary hypertension

    Directory of Open Access Journals (Sweden)

    Fadel Elie

    2011-09-01

    Full Text Available Abstract Background Involvement of inflammation in pulmonary hypertension (PH has previously been demonstrated and recently, immune-modulating dendritic cells (DCs infiltrating arterial lesions in patients suffering from idiopathic pulmonary arterial hypertension (IPAH and in experimental monocrotaline-induced PH have been reported. Occurrence of perivascular inflammatory cells could be linked to local increase of oxidative stress (OS, as it has been shown for systemic atherosclerosis. The impact of OS on vascular remodeling in PH is still to be determined. We hypothesized, that augmented blood-flow could increase OS and might thereby contribute to DC/inflammatory cell-recruitment and smooth-muscle-cell-proliferation. Methods We applied a monocrotaline-induced PH-model and combined it with permanent flow-challenge. Thirty Sprague-Dawley rats were assigned to following groups: control, monocrotaline-exposure (MCT, monocrotaline-exposure/pneumonectomy (MCT/PE. Results Hemodynamic exploration demonstrated most severe effects in MCT/PE, corresponding in histology to exuberant medial and adventitial remodeling of pulmonary muscular arteries, and intimal remodeling of smaller arterioles; lung-tissue PCR evidenced increased expression of DCs-specific fascin, CD68, proinflammatory cytokines (IL-6, RANTES, fractalkine in MCT/PE and to a lesser extent in MCT. Major OS enzyme NOX-4 was maximal in MCT/PE. Antioxidative stress enzymes Mn-SOD and glutathion-peroxidase-1 were significantly elevated, while HO-1 showed maximal expression in MCT with significant decrease in MCT/PE. Catalase was decreased in MCT and MCT/PE. Expression of NOX-4, but also of MN-SOD in MCT/PE was mainly attributed to a highly increased number of interstitial and perivascular CXCR4/SDF1 pathway-recruited mast-cells. Stress markers malonedialdehyde and nitrotyrosine were produced in endothelial cells, medial smooth muscle and perivascular leucocytes of hypertensive vasculature

  13. Design and Development of a High Efficiency CarbonGranular Bed Filter in Industrial Scale

    Institute of Scientific and Technical Information of China (English)

    张济宇; 旷戈; 林诚

    2004-01-01

    The new dust removal technical route using the carbon-granular bed filter, packed of carbon particles with appropriate grade derive from an online-process vibration sieve, to replace the traditional baggy filter had been developed successfully for capturing the micro-carbon dusts produced from pulverization of petroleum coke,and the green close loop of carbon materials is thus completed in the combined pulverizing and classifying system and pulverized carbon dust removal process. The high dust removal efficiency greater than 99%, low outlet dust concentration less than 100 mg-m-S, low pressure drop through dust filtration chamber less than 980 Pa, simple and easy design, and flexible and stable operation were achieved also with the carbon-granular bed filter in both bench and industrial scale operations.

  14. High efficiency dye sensitized solar cell made by carbon derived from sucrose

    Science.gov (United States)

    Kumar, Rahul; Nemala, Siva Sankar; Mallick, Sudhanshu; Bhargava, Parag

    2017-02-01

    Carbon materials represent an attractive alternative to platinum based counter electrodes in DSSCs. Graphitic carbon produced from carbonization of sucrose has been used for making counter electrode for DSSCs. It was observed that increment in thickness of carbon counter electrode improves the performance of DSSCs. Electrochemical impedance spectroscopy, Tafel polarization and cyclic voltammetry measurements suggest that sucrose derived carbon based counter electrode shows fast reduction rate of I3- compare with platinum based counter electrode. DSSCs based on sucrose derived carbon exhibit high power conversion efficiency (PCE) of 9.96% and fill factor (FF) of 0.72 which is higher than PCE of 9.39% and FF of 0.67 of the cells with platinum (Pt) based counter electrode.

  15. Random vs realistic amorphous carbon models for high resolution microscopy and electron diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Ricolleau, C., E-mail: Christian.Ricolleau@univ-paris-diderot.fr; Alloyeau, D. [Laboratoire Matériaux et Phénomènes Quantiques, CNRS-UMR 7162, Université Paris Diderot-Paris 7, Case 7021, 75205 Paris Cedex 13 (France); Le Bouar, Y.; Amara, H.; Landon-Cardinal, O. [Laboratoire d' Etude des Microstructures, UMR CNRS/Onera, 29, avenue de la Division Leclerc, 92322 Châtillon (France)

    2013-12-07

    Amorphous carbon and amorphous materials in general are of particular importance for high resolution electron microscopy, either for bulk materials, generally covered with an amorphous layer when prepared by ion milling techniques, or for nanoscale objects deposited on amorphous substrates. In order to quantify the information of the high resolution images at the atomic scale, a structural modeling of the sample is necessary prior to the calculation of the electron wave function propagation. It is thus essential to be able to reproduce the carbon structure as close as possible to the real one. The approach we propose here is to simulate a realistic carbon from an energetic model based on the tight-binding approximation in order to reproduce the important structural properties of amorphous carbon. At first, we compare this carbon with the carbon obtained by randomly generating the carbon atom positions. In both cases, we discuss the limit thickness of the phase object approximation. In a second step, we show the influence of both carbons models on (i) the contrast of Cu, Ag, and Au single atoms deposited on carbon and (ii) the determination of the long-range order parameter in CoPt bimetallic nanoalloys.

  16. Removal of H2S using molten carbonate at high temperature.

    Science.gov (United States)

    Kawase, Makoto; Otaka, Maromu

    2013-12-01

    Gasification is considered to be an effective process for energy conversion from various sources such as coal, biomass, and waste. Cleanup of the hot syngas produced by such a process may improve the thermal efficiency of the overall gasification system. Therefore, the cleanup of hot syngas from biomass gasification using molten carbonate is investigated in bench-scale tests. Molten carbonate acts as an absorbent during desulfurization and dechlorination and as a thermal catalyst for tar cracking. In this study, the performance of molten carbonate for removing H2S was evaluated. The temperature of the molten carbonate was set within the range from 800 to 1000 °C. It is found that the removal of H2S is significantly affected by the concentration of CO2 in the syngas. When only a small percentage of CO2 is present, desulfurization using molten carbonate is inadequate. However, when carbon elements, such as char and tar, are continuously supplied, H2S removal can be maintained at a high level. To confirm the performance of the molten carbonate gas-cleaning system, purified biogas was used as a fuel in power generation tests with a molten carbonate fuel cell (MCFC). The fuel cell is a high-performance sensor for detecting gaseous impurities. When purified gas from a gas-cleaning reactor was continuously supplied to the fuel cell, the cell voltage remained stable. Thus, the molten carbonate gas-cleaning reactor was found to afford good gas-cleaning performance.

  17. Carbon Surface Layers on a High-Rate LiFePO4

    Energy Technology Data Exchange (ETDEWEB)

    Gabrisch, Heike; Wilcox, James D.; Doeff, Marca M.

    2005-09-06

    Transmission electron microscopy (TEM) was used to image particles of a high-rate LiFePO4 sample containing a small amount of in situ carbon. The particle morphology is highly irregular, with a wide size distribution. Nevertheless, coatings, varying from about 5-10 nm in thickness, could readily be detected on surfaces of particles as well as on edges of agglomerates. Elemental mapping using Energy Filtered TEM (EFTEM) indicates that these very thin surface layers are composed of carbon. These observations have important implications for the design of high-rate LiFePO4 materials in which, ideally, a minimal amount of carbon coating is used.

  18. Reproducibility of high-resolution MRI for the middle cerebral artery plaque at 3 T

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Wan-Qun [Department of Radiology, Guangdong Academy of Medical Sciences, Guangdong General Hospital, Guangzhou, Guangdong 510080 (China); Huang, Biao, E-mail: cjr.huangbiao@vip.163.com [Department of Radiology, Guangdong Academy of Medical Sciences, Guangdong General Hospital, Guangzhou, Guangdong 510080 (China); Liu, Xin-Tong [Department of Neurology, Guangdong Academy of Medical Sciences, Guangdong General Hospital, Guangzhou, Guangdong 510080 (China); Liu, Hong-Jun; Li, Pei-Jun [Department of Radiology, Guangdong Academy of Medical Sciences, Guangdong General Hospital, Guangzhou, Guangdong 510080 (China); Zhu, Wen-Zhen, E-mail: zhuwenzhen@hotmail.com [Department of Radiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430030 (China)

    2014-01-15

    Purpose: To assess the reproducibility of HR-MRI for the identification of MCA atherosclerotic plaque components and quantification of stenosis. Materials and methods: Seventy-three consecutive subjects who initially had ischemic stroke or asymptomatic MCA stenosis (>50%) were enrolled in the study. All subjects were scanned using 3.0 T MRI. Two independent readers reviewed all images and one reader reevaluated all images four weeks later. The tissue components of plaques were analyzed qualitatively and the vessels were quantitative measured. Results: HR-MRI displayed the artery wall and lumen clearly. The intra-observer reproducibility was excellent for the identification of plaques (kappa [κ] = 0.96; 95% CI: 0.83–1.04) and contrast enhancement (κ = 0.89; 0.78–0.95); it was substantial for intra-plaque hemorrhage (κ = 0.79; 0.57–0.96) and the fibrous cap (κ = 0.65; 0.42–0.86). The inter-observer reproducibility was excellent for plaques (κ = 0.92; 0.73–1.06), substantial for contrast enhancement (κ = 0.80; 0.65–0.93), intra-plaque hemorrhage (κ = 0.68; 0.47–0.92) and moderate for the fibrous cap (κ = 0.58; 0.44–0.79). Both intra-observer and inter-observer reproducibility were excellent for quantitative vessel, lumen and wall measurements with intraclass correlation coefficients ranging from 0.91 to 0.97 and 0.87 to 0.96, respectively. However, vessel and wall areas and the intervals defined by the Bland–Altman plots were wide in comparison to the mean. Conclusions: The identification of MCA atherosclerotic plaque components and the quantification of vessel and lumen measurements are reproducible. The reproducibility is overall acceptable. HR-MRI may provide a useful tool for clinical risk evaluation in MCA atherosclerosis.

  19. A highly viscous imidazolium ionic liquid inside carbon nanotubes.

    Science.gov (United States)

    Ohba, Tomonori; Chaban, Vitaly V

    2014-06-12

    We report a combined experimental (X-ray diffraction) and theoretical (molecular dynamics, hybrid density functional theory) study of 1-ethyl-3-methylimidazolium chloride, [C2C1MIM][Cl], inside carbon nanotubes (CNTs). We show that despite its huge viscosity [C2C1MIM][Cl] readily penetrates into 1-3 nm wide CNTs at slightly elevated temperatures (323-363 K). Molecular simulations were used to assign atom-atom peaks. Experimental and simulated structures of RTIL inside CNT and in bulk phase are in good agreement. We emphasize a special role of the CNT-chloride interactions in the successful adsorption of [C2C1MIM][Cl] on the inner sidewalls of 1-3 nm carbon nanotubes.

  20. STRATEGIES AND TECHNOLOGY FOR MANAGING HIGH-CARBON ASH

    Energy Technology Data Exchange (ETDEWEB)

    Robert Hurt; Eric Suuberg; John Veranth; Xu Chen

    2003-05-20

    The overall objective of the present project is to identify and assess strategies and solutions for the management of industry problems related to carbon in ash. Specific research issues to be addressed include: (1) the effect of parent fuel selection on ash properties and adsorptivity, including a first ever examination of the air entrainment behavior of ashes from alternative (non-coal) fuels; (2) the effect of various low-NOx firing modes on ash properties and adsorptivity; and (3) the kinetics and mechanism of ash ozonation. This data will provide scientific and engineering support of the ongoing process development activities. During this fourth project period we completed the characterization of ozone-treated carbon surfaces and wrote a comprehensive report on the mechanism through which ozone suppresses the adsorption of concrete surfactants.

  1. Carbon nanotube quantum dots as highly sensitive THz spectrometers

    Science.gov (United States)

    Rinzan, Mohamed; Jenkins, Greg; Drew, Dennis; Shafranjuk, Serhii; Barbara, Paola

    2012-02-01

    We show that carbon nanotube quantum dots (CNT-Dots) coupled to antennas are extremely sensitive, broad-band, terahertz quantum detectors. Their response is due to photon-assisted single-electron tunneling (PASET)[1], but cannot be fully understood with orthodox PASET models[2]. We consider intra-dot excitations and non-equilibrium cooling to explain the anomalous response. REFERENCES: [1] Y. Kawano, S. Toyokawa, T. Uchida and K. Ishibashi, THz photon assisted tunneling in carbon-nanotube quantum dots, Journal of Applied Physics 103, 034307 (2008). [2] P. K. Tien and J. P. Gordon, Multiphoton Process Observed in the Interaction of Microwave Fields with the Tunneling between Superconductor Films, Phys. Rev. 129, 647 (1963).

  2. A Highly Viscous Imidazolium Ionic Liquid inside Carbon Nanotubes

    DEFF Research Database (Denmark)

    Ohba, T.; Chaban, Vitaly V.

    2014-01-01

    We report a combined experimental (X-ray diffraction) and theoretical (molecular dynamics, hybrid density functional theory) study of 1-ethyl-3-methylimidazolium chloride, [C2C1MIM][Cl], inside carbon nanotubes (CNTs). We show that despite its huge viscosity [C2C1MIM][Cl] readily penetrates into 1......-3 nm wide CNTs at slightly elevated temperatures (323-363 K). Molecular simulations were used to assign atom-atom peaks. Experimental and simulated structures of RTIL inside CNT and in bulk phase are in good agreement. We emphasize a special role of the CNT-chloride interactions in the successful...... adsorption of [C2C1MIM][Cl] on the inner sidewalls of 1-3 nm carbon nanotubes....

  3. STRATEGIES AND TECHNOLOGY FOR MANAGING HIGH-CARBON ASH

    Energy Technology Data Exchange (ETDEWEB)

    Robert Hurt; Eric Suuberg; John Veranth; Xu Chen

    2002-09-10

    The overall objective of the present project is to identify and assess strategies and solutions for the management of industry problems related to carbon in ash. Specific research issues to be addressed include: (1) the effect of parent fuel selection on ash properties and adsorptivity, including a first ever examination of the air entrainment behavior of ashes from alternative (non-coal) fuels; (2) the effect of various low-NOx firing modes on ash properties and adsorptivity; and (3) the kinetics and mechanism of ash ozonation. This data will provide scientific and engineering support of the ongoing process development activities. During this fourth project period we completed the characterization of ozone-treated carbon surfaces and wrote a comprehensive report on the mechanism through which ozone suppresses the adsorption of concrete surfactants.

  4. Carbon budget estimation of a subarctic catchment using a dynamic ecosystem model at high spatial resolution

    Science.gov (United States)

    Tang, J.; Miller, P. A.; Persson, A.; Olefeldt, D.; Pilesjo, P.; Heliasz, M.; Jackowicz-Korczynski, M.; Yang, Z.; Smith, B.; Callaghan, T. V.; Christensen, T. R.

    2015-05-01

    A large amount of organic carbon is stored in high-latitude soils. A substantial proportion of this carbon stock is vulnerable and may decompose rapidly due to temperature increases that are already greater than the global average. It is therefore crucial to quantify and understand carbon exchange between the atmosphere and subarctic/arctic ecosystems. In this paper, we combine an Arctic-enabled version of the process-based dynamic ecosystem model, LPJ-GUESS (version LPJG-WHyMe-TFM) with comprehensive observations of terrestrial and aquatic carbon fluxes to simulate long-term carbon exchange in a subarctic catchment at 50 m resolution. Integrating the observed carbon fluxes from aquatic systems with the modeled terrestrial carbon fluxes across the whole catchment, we estimate that the area is a carbon sink at present and will become an even stronger carbon sink by 2080, which is mainly a result of a projected densification of birch forest and its encroachment into tundra heath. However, the magnitudes of the modeled sinks are very dependent on future atmospheric CO2 concentrations. Furthermore, comparisons of global warming potentials between two simulations with and without CO2 increase since 1960 reveal that the increased methane emission from the peatland could double the warming effects of the whole catchment by 2080 in the absence of CO2 fertilization of the vegetation. This is the first process-based model study of the temporal evolution of a catchment-level carbon budget at high spatial resolution, including both terrestrial and aquatic carbon. Though this study also highlights some limitations in modeling subarctic ecosystem responses to climate change, such as aquatic system flux dynamics, nutrient limitation, herbivory and other disturbances, and peatland expansion, our study provides one process-based approach to resolve the complexity of carbon cycling in subarctic ecosystems while simultaneously pointing out the key model developments for capturing

  5. Highly Efficient Oxidative Cleavage of Carbon-Carbon Double Bond over meso-Tetraphenyl Cobalt Porphyrin Catalyst in the Presence of Molecular Oxygen

    Institute of Scientific and Technical Information of China (English)

    周贤太; 纪红兵

    2012-01-01

    Highly efficient and selective carbon-carbon double bond aerobic cleavage of olefins catalyzed by metallopor- phyrins was investigated, and carbonyl compounds and epoxide were produced as the main products. CoTPP (co- balt meso-tetraphenyl porphyrin) showed excellent activity for the oxidative cleavage of carbon-carbon double bond by using styrene as model compound, in which the TOF (turnover frequency) and selectivity toward benzaldehyde was obtained with 2×10^4h-1 and 86%,respectively.

  6. High Volume Fraction Carbon Nanotube Composites for Aerospace Applications

    Science.gov (United States)

    Siochi, Emilie J.; Kim, Jae-Woo; Sauti, Godfrey; Cano, Roberto J.; Wincheski, Russell A.; Ratcliffe, James G.; Czabaj, Michael; Jensen, Benjamin D.; Wise, Kristopher E.

    2015-01-01

    Reported nanoscale mechanical properties of carbon nanotubes (CNTs) suggest that their use may enable the fabrication of significantly lighter structures for use in space applications. To be useful in the fabrication of large structures, however, their attractive nanoscale properties must be retained as they are scaled up to bulk materials and converted into practically useful forms. Advances in CNT production have significantly increased the quantities available for use in manufacturing processes, but challenges remain with the retention of nanoscale properties in larger assemblies of CNTs. This work summarizes recent progress in producing carbon nanotube composites with tensile properties approaching those of carbon fiber reinforced polymer composites. These advances were achieved in nanocomposites with CNT content of 70% by weight. The processing methods explored to yield these CNT composite properties will be discussed, as will the characterization and test methods that were developed to provide insight into the factors that contribute to the enhanced tensile properties. Technology maturation was guided by parallel advancements in computational modeling tools that aided in the interpretation of experimental data.

  7. High-pressure phase equilibria for the carbon dioxide + 3-pentanol and carbon dioxide + 3-pentanol + water systems

    Energy Technology Data Exchange (ETDEWEB)

    Lee, H.S.; Mun, S.Y.; Lee, H. [Korea Advanced Inst. of Science and Technology, Taejon (Korea, Republic of). Dept. of Chemical Engineering

    1999-05-01

    High-pressure vapor-liquid equilibria for the binary carbon dioxide + 3-pentanol system were measured at 313.2 K. The phase equilibrium apparatus used in this work was of the circulation type in which the coexisting phases were recirculated, on-line sampled, and analyzed. The critical pressure and corresponding mole fraction of carbon dioxide at 313.2 K were found to be 8.22 MPa and 0.974, respectively, for this binary system. The phase equilibria for the ternary carbon dioxide + 3-pentanol + water system were also measured at 313.2 K and pressures of 2.00, 4.00, 6.00, 8.00, and 8.25 MPa. This ternary system showed the liquid-liquid-vapor (LLV) phase behavior over the range of pressure up to the critical pressure of 8.25 MPa. The binary equilibrium data were all reasonably well-correlated with the Redlich-Kwong, Soave-Redlich-Kwong, Peng-Robinson, and Patel-Teja equations of state incorporated with the eight different mixing rules: the van der Waals, Panagiotopoulos-Reic, and six modified Huron-Vidal mixing rules with UNIQUAC parameters. For the prediction of high-pressure phase equilibria for the systems containing carbon dioxide and alcohols, the SRK-MHV2 might reproduce many features of the measured behavior although further tests are needed with other systems.

  8. High-resolution mapping of forest carbon stocks in the Colombian Amazon

    Directory of Open Access Journals (Sweden)

    G. P. Asner

    2012-07-01

    Full Text Available High-resolution mapping of tropical forest carbon stocks can assist forest management and improve implementation of large-scale carbon retention and enhancement programs. Previous high-resolution approaches have relied on field plot and/or light detection and ranging (LiDAR samples of aboveground carbon density, which are typically upscaled to larger geographic areas using stratification maps. Such efforts often rely on detailed vegetation maps to stratify the region for sampling, but existing tropical forest maps are often too coarse and field plots too sparse for high-resolution carbon assessments. We developed a top-down approach for high-resolution carbon mapping in a 16.5 million ha region (> 40% of the Colombian Amazon – a remote landscape seldom documented. We report on three advances for large-scale carbon mapping: (i employing a universal approach to airborne LiDAR-calibration with limited field data; (ii quantifying environmental controls over carbon densities; and (iii developing stratification- and regression-based approaches for scaling up to regions outside of LiDAR coverage. We found that carbon stocks are predicted by a combination of satellite-derived elevation, fractional canopy cover and terrain ruggedness, allowing upscaling of the LiDAR samples to the full 16.5 million ha region. LiDAR-derived carbon maps have 14% uncertainty at 1 ha resolution, and the regional map based on stratification has 28% uncertainty in any given hectare. High-resolution approaches with quantifiable pixel-scale uncertainties will provide the most confidence for monitoring changes in tropical forest carbon stocks. Improved confidence will allow resource managers and decision makers to more rapidly and effectively implement actions that better conserve and utilize forests in tropical regions.

  9. High-resolution Mapping of Forest Carbon Stocks in the Colombian Amazon

    Directory of Open Access Journals (Sweden)

    G. P. Asner

    2012-03-01

    Full Text Available High-resolution mapping of tropical forest carbon stocks can assist forest management and improve implementation of large-scale carbon retention and enhancement programs. Previous high-resolution approaches have relied on field plot and/or Light Detection and Ranging (LiDAR samples of aboveground carbon density, which are typically upscaled to larger geographic areas using stratification maps. Such efforts often rely on detailed vegetation maps to stratify the region for sampling, but existing tropical forest maps are often too coarse and field plots too sparse for high resolution carbon assessments. We developed a top-down approach for high-resolution carbon mapping in a 16.5 million ha region (>40 % of the Colombian Amazon – a remote landscape seldom documented. We report on three advances for large-scale carbon mapping: (i employing a universal approach to airborne LiDAR-calibration with limited field data; (ii quantifying environmental controls over carbon densities; and (iii developing stratification- and regression-based approaches for scaling up to regions outside of LiDAR coverage. We found that carbon stocks are predicted by a combination of satellite-derived elevation, fractional canopy cover and terrain ruggedness, allowing upscaling of the LiDAR samples to the full 16.5 million ha region. LiDAR-derived carbon mapping samples had 14.6 % uncertainty at 1 ha resolution, and regional maps based on stratification and regression approaches had 25.6 % and 29.6 % uncertainty, respectively, in any given hectare. High-resolution approaches with reported local-scale uncertainties will provide the most confidence for monitoring changes in tropical forest carbon stocks. Improved confidence will allow resource managers and decision-makers to more rapidly and effectively implement actions that better conserve and utilize forests in tropical regions.

  10. Microstructural study of the ablation behaviors of 3D fine weave pierced Carbon/Carbon composites using plasma torch at ultra-high temperature

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    A simple and effective method of testing ablation behaviors of carbon/carbon composites at high temperature was provided, which used plasma torch as the heater. The ablation resistance of 3D fine weave pierced carbon/carbon composites at high temperature was also studied. The results show that temperature of the plasma flame is very high which is much closer to the real work environment of carbon/carbon composites. The factors that affect the ablation characters of carbon/carbon composites depend on both the properties of their components and the environmental conditions in which the material is placed. The ablation behaviors of C/C composites change from the center flame region predominantly influenced by sublimation of graphite to the region close to the outer flame influenced mainly by oxidization of graphite. The sublimation ability of carbon matrix is equal to that of carbon fibers but the oxidization ability of carbon fibers is significantly enhanced compared to that of carbon matrix.

  11. Hollow Carbon Nanofiber-Encapsulated Sulfur Cathodes for High Specific Capacity Rechargeable Lithium Batteries

    KAUST Repository

    Zheng, Guangyuan

    2011-10-12

    Sulfur has a high specific capacity of 1673 mAh/g as lithium battery cathodes, but its rapid capacity fading due to polysulfides dissolution presents a significant challenge for practical applications. Here we report a hollow carbon nanofiber-encapsulated sulfur cathode for effective trapping of polysulfides and demonstrate experimentally high specific capacity and excellent electrochemical cycling of the cells. The hollow carbon nanofiber arrays were fabricated using anodic aluminum oxide (AAO) templates, through thermal carbonization of polystyrene. The AAO template also facilitates sulfur infusion into the hollow fibers and prevents sulfur from coating onto the exterior carbon wall. The high aspect ratio of the carbon nanofibers provides an ideal structure for trapping polysulfides, and the thin carbon wall allows rapid transport of lithium ions. The small dimension of these nanofibers provides a large surface area per unit mass for Li2S deposition during cycling and reduces pulverization of electrode materials due to volumetric expansion. A high specific capacity of about 730 mAh/g was observed at C/5 rate after 150 cycles of charge/discharge. The introduction of LiNO3 additive to the electrolyte was shown to improve the Coulombic efficiency to over 99% at C/5. The results show that the hollow carbon nanofiber-encapsulated sulfur structure could be a promising cathode design for rechargeable Li/S batteries with high specific energy. © 2011 American Chemical Society.

  12. Feasibility of low-dose contrast medium high pitch CT angiography for the combined evaluation of coronary, head and neck arteries.

    Directory of Open Access Journals (Sweden)

    Zhiwei Wang

    Full Text Available PURPOSE: To evaluate the image quality and radiation dose of combined heart, head, and neck CT angiography (CTA using prospectively electrocardiography (ECG-triggered high-pitch spiral scan protocol, compared with single coronary CTA. MATERIALS AND METHODS: 151 consecutive patients were prospectively included and randomly divided into three groups. Group 1 (n = 47 underwent combined heart, neck, and head CTA using prospectively ECG-triggered high-pitch spiral (Flash scan protocol with a single-phase intravenous injection of iodinated contrast and saline flush; Group 2 (n = 51 underwent single coronary CTA with Flash scan protocol; and Group 3 (n = 53 underwent single coronary CTA with prospective sequence scan protocol. All patients were examined on a dual source CT (Definition FLASH. The image quality was determined for each CT study. RESULTS: Patients of scanning protocol Group 1, 2, and 3 showed no significant differences in age, sex, heart rates, and BMI. Evaluation of coronary artery image quality showed comparable results in the three scanning protocol groups on a per patient-based analysis. In group 1, image quality was found to be sufficient to be diagnostic in all arterial segments of carotid arteries. The mean dose-length product (DLP for group 1 was 256.3±24.5 mGy×cm and was significantly higher in comparison with group 2 (93.4±19.9 mGy×cm; p < 0.001. However, there was no significant difference of DLP between group 1 and group 3 (254.1±69.9 mGy×cm. CONCLUSIONS: The combined heart, neck, and head arteries scan using prospectively electrocardiography (ECG-triggered high-pitch spiral scan protocol in 1 single examination resulted in an excellent opacification of the aorta, the carotid arteries, and the coronary arteries and provided a good image quality with low radiation dose.

  13. New Activated Carbon with High Thermal Conductivity and Its Microwave Regeneration Performance

    Institute of Scientific and Technical Information of China (English)

    GU Xuexian; SU Zhanjun; XI Hongxia

    2016-01-01

    Using a walnut shell as a carbon source and ZnCl2 as an activating agent, we resolved the temperature gradient problems of activated carbon in the microwave desorption process. An appropriate amount of silicon carbide was added to prepare the composite activated carbon with high thermal conductivity while developing VOC adsorption-microwave regeneration technology. The experimental results show that the coefficient of thermal conductivity of SiC-AC is three times as much as those of AC and SY-6. When microwave power was 480 W in its microwave desorption , the temperature of the bed thermal desorption was 10℃ to 30℃below that of normal activated carbon prepared in our laboratory. The toluene desorption activation energy was 16.05 kJ∙mol-1, which was 15% less than the desorption activation energy of commercial activated carbon. This study testified that the process could maintain its high adsorption and regeneration desorption performances.

  14. Early pulmonary response is critical for extra-pulmonary carbon nanoparticle mediated effects: comparison of inhalation versus intra-arterial infusion exposures in mice.

    Science.gov (United States)

    Ganguly, Koustav; Ettehadieh, Dariusch; Upadhyay, Swapna; Takenaka, Shinji; Adler, Thure; Karg, Erwin; Krombach, Fritz; Kreyling, Wolfgang G; Schulz, Holger; Schmid, Otmar; Stoeger, Tobias

    2017-06-20

    The death toll associated with inhaled ambient particulate matter (PM) is attributed mainly to cardio-vascular rather than pulmonary effects. However, it is unclear whether the key event for cardiovascular impairment is particle translocation from lung to circulation (direct effect) or indirect effects due to pulmonary particle-cell interactions. In this work, we addressed this issue by exposing healthy mice via inhalation and intra-arterial infusion (IAI) to carbon nanoparticles (CNP) as surrogate for soot, a major constituent of (ultrafine) urban PM. Equivalent surface area CNP doses in the blood (30mm(2) per animal) were applied by IAI or inhalation (lung-deposited dose 10,000mm(2); accounting for 0.3% of lung-to-blood CNP translocation). Mice were analyzed for changes in hematology and molecular markers of endothelial/epithelial dysfunction, pro-inflammatory reactions, oxidative stress, and coagulation in lungs and extra-pulmonary organs after CNP inhalation (4 h and 24 h) and CNP infusion (4 h). For methodological reasons, we used two different CNP types (spark-discharge and Printex90), with very similar physicochemical properties [≥98 and ≥95% elemental carbon; 10 and 14 nm primary particle diameter; and 800 and 300 m(2)/g specific surface area] for inhalation and IAI respectively. Mild pulmonary inflammatory responses and significant systemic effects were observed following 4 h and 24 h CNP inhalation. Increased retention of activated leukocytes, secondary thrombocytosis, and pro-inflammatory responses in secondary organs were detected following 4 h and 24 h of CNP inhalation only. Interestingly, among the investigated extra-pulmonary tissues (i.e. aorta, heart, and liver); aorta revealed as the most susceptible extra-pulmonary target following inhalation exposure. Bypassing the lungs by IAI however did not induce any extra-pulmonary effects at 4 h as compared to inhalation. Our findings indicate that extra-pulmonary effects due to CNP

  15. Metallic tin quantum sheets confined in graphene toward high-efficiency carbon dioxide electroreduction

    Science.gov (United States)

    Lei, Fengcai; Liu, Wei; Sun, Yongfu; Xu, Jiaqi; Liu, Katong; Liang, Liang; Yao, Tao; Pan, Bicai; Wei, Shiqiang; Xie, Yi

    2016-09-01

    Ultrathin metal layers can be highly active carbon dioxide electroreduction catalysts, but may also be prone to oxidation. Here we construct a model of graphene confined ultrathin layers of highly reactive metals, taking the synthetic highly reactive tin quantum sheets confined in graphene as an example. The higher electrochemical active area ensures 9 times larger carbon dioxide adsorption capacity relative to bulk tin, while the highly-conductive graphene favours rate-determining electron transfer from carbon dioxide to its radical anion. The lowered tin-tin coordination numbers, revealed by X-ray absorption fine structure spectroscopy, enable tin quantum sheets confined in graphene to efficiently stabilize the carbon dioxide radical anion, verified by 0.13 volts lowered potential of hydroxyl ion adsorption compared with bulk tin. Hence, the tin quantum sheets confined in graphene show enhanced electrocatalytic activity and stability. This work may provide a promising lead for designing efficient and robust catalysts for electrolytic fuel synthesis.

  16. Molecular interactions on single-walled carbon nanotubes revealed by high-resolution transmission microscopy

    National Research Council Canada - National Science Library

    Umeyama, Tomokazu; Baek, Jinseok; Sato, Yuta; Suenaga, Kazu; Abou-Chahine, Fawzi; Tkachenko, Nikolai V; Lemmetyinen, Helge; Imahori, Hiroshi

    2015-01-01

    .... Here, we show that the sidewall of a single-walled carbon nanotube (SWNT) represents a unique molecular dimer platform that can be directly visualized using high-resolution transmission electron microscopy...

  17. Inactivation of L. fructivorans in Sake Using a Continuous Flow System for High-Pressure Carbonation

    National Research Council Canada - National Science Library

    TANIMOTO, Shota; MATSUMOTO, Hideyuki; FUJII, Kazuyoshi; OHDOI, Ritsushi; SAKAMOTO, Koji; YAMANE, Yuichi; MIYAKE, Masaki; SHIMODA, Mitsuya; OSAJIMA, Yutaka

    2007-01-01

    ...) quality, was investigated using a continuous flow system for high-pressure carbonation. In addition, the effects of ethanol and sugar concentration on lactic acid bacteria inactivation were investigated. Cells of L. fructivorans (1×106CFU/ml...

  18. TEMPERATURE-DEFORMATION CRITERION OF OPTIMIZATION OF FINE DRAWING HIGH CARBON WIRE ROUTE

    Directory of Open Access Journals (Sweden)

    Y. L. Bobarikin

    2012-01-01

    Full Text Available The temperature-deformation criterion of assessment and optimization of routes of the thin high-carbon wire drawing enabling to increase plastic properties of wire at retaining of its durability is offered.

  19. Influence of the Manufacturing Process on Defects in the Galvanized Coating of High Carbon Steel Wires

    National Research Council Canada - National Science Library

    Marcello Gelfi; Luigi Solazzi; Sandro Poli

    2017-01-01

    This study is a detailed failure analysis of galvanized high carbon steel wires, which developed coating cracks during the torsion test performed as a quality control at the end of the manufacturing process...

  20. Freestanding bucky paper with high strength from multi-wall carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Li, Zhonglai, E-mail: zhonglai.li@ul.ie [Department of Chemistry, Materials Section and Supercritical Fluid Centre, University College Cork, Cork (Ireland); Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College Dublin, Dublin 2 (Ireland); Xu, Ju [Tyndall National Institute, University College Cork, Lee Maltings, Prospect Row, Cork (Ireland); O' Byrne, Justin P.; Chen, Lan; Wang, Kaixue [Department of Chemistry, Materials Section and Supercritical Fluid Centre, University College Cork, Cork (Ireland); Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College Dublin, Dublin 2 (Ireland); Morris, Michael A.; Holmes, Justin D. [Department of Chemistry, Materials Section and Supercritical Fluid Centre, University College Cork, Cork (Ireland); Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College Dublin, Dublin 2 (Ireland); Tyndall National Institute, University College Cork, Lee Maltings, Prospect Row, Cork (Ireland)

    2012-08-15

    Bucky papers have been investigated by some research groups, however, due to different qualities of carbon nanotubes used, various results of strength and electronic properties were reported in the literatures. In this article, the effects of carbon nanotubes synthesized over different catalysts on the qualities of bucky papers were systemically investigated. Multi-wall carbon nanotubes were synthesized over a series of MgO supported catalysts with different weight ratios of Mo and Co. As the ratios of Mo/Co in the catalysts were increased from 0 to 3, the yields of carbon nanotubes were enhanced from 7 wt% to 400 wt%. However, the yield enhancement of carbon nanotubes was achieved at the expense of higher proportion of structural defects within carbon nanotubes, which has been proved by Raman spectroscopy and thermogravimetry analysis. It was demonstrated that the tensile strength of bucky paper composed of numerous MCNTs bundles strongly depends on the structure of carbon nanotubes used. By optimizing reaction conditions, a bucky paper with high strain up to 15.36 MPa and electrical conductivity of 61.17 S cm{sup -1} was obtained by Supercritical Fluid (SCF) drying technique. -- Highlights: Black-Right-Pointing-Pointer Multi-wall carbon nanotube bucky paper. Black-Right-Pointing-Pointer Structural defects of carbon nanotubes. Black-Right-Pointing-Pointer CoMo catalyst. Black-Right-Pointing-Pointer Tensile strength of bucky paper.

  1. Penile angiography and superselective embolization therapy in arterial priapism; Penisangiographie und superselektive Embolisationstherapie bei high-flow Priapismus

    Energy Technology Data Exchange (ETDEWEB)

    Dinkel, H.P.; Triller, J. [Inst. fuer Diagnostische Radiologie, Inselspital, Univ. Bern (Switzerland); Hochreiter, W. [Urologische Klinik, Inselspital, Univ. Bern (Switzerland)

    2003-08-01

    Purpose: To report feasibility, benefit and complications of penile angiography and superselective penile embolization in arterial priapism. Materials and Methods: Four consecutive patients (aged 28, 29, 40 and 49 years), who underwent penile angiography for arterial priapism (high-flow priapism) within a four-year period, were identified by a keyword search of our radiology information system. One patient had sustained a direct penile trauma (severe blow to the erected penis) and three patients suffered from recurrent spontaneous priapism. All patients had previously undergone corporeal aspiration and noradrenaline injection to achieve detumescence. Two patients had one or several unsuccessful spongiocavernous shunt procedures. Results: In three of the four patients, superselective pudendal and penile angiography demonstrated pathologic arteriocavernous shunting. In two of the three patients, superselective embolization using a coaxial micro-catheter was attempted. In one of the two patients, the cavernous artery became spastic before embolization material was actually injected, inducing immediate and lasting detumescence. In the other patient, unilateral Gelfoam embolization led to immediate detumescence but the priapism recurred 12 hours after the procedure. A subsequent contralateral Gelfoam embolization was successful. Erectile function was preserved in all cases. No procedure-related complications occurred. Conclusion: Our experience supports the prevailing opinion found in the current literature that superselective coaxial embolization constitutes the treatment of choice in patients with high-flow priapism. Prognosis is good with high probability of preserving the erectile function. (orig.) [German] Ziel: Untersuchung der Interventionsmoeglichkeiten bei arteriellem (high-flow) Priapismus durch endovaskulaere superselektive Embolisation der Penisarterien. Methode: Alle innerhalb eines Vierjahreszeitraums (1/99-5/2002) wegen Priapismus zur Angiographie

  2. A High-Flux, Flexible Membrane with Parylene-encapsulated Carbon Nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Park, H G; In, J; Kim, S; Fornasiero, F; Holt, J K; Grigoropoulos, C P; Noy, A; Bakajin, O

    2008-03-14

    We present fabrication and characterization of a membrane based on carbon nanotubes (CNTs) and parylene. Carbon nanotubes have shown orders of magnitude enhancement in gas and water permeability compared to estimates generated by conventional theories [1, 2]. Large area membranes that exhibit flux enhancement characteristics of carbon nanotubes may provide an economical solution to a variety of technologies including water desalination [3] and gas sequestration [4]. We report a novel method of making carbon nanotube-based, robust membranes with large areas. A vertically aligned dense carbon nanotube array is infiltrated with parylene. Parylene polymer creates a pinhole free transparent film by exhibiting high surface conformity and excellent crevice penetration. Using this moisture-, chemical- and solvent-resistant polymer creates carbon nanotube membranes that promise to exhibit high stability and biocompatibility. CNT membranes are formed by releasing a free-standing film that consists of parylene-infiltrated CNTs, followed by CNT uncapping on both sides of the composite material. Thus fabricated membranes show flexibility and ductility due to the parylene matrix material, as well as high permeability attributed to embedded carbon nanotubes. These membranes have a potential for applications that may require high flux, flexibility and durability.

  3. Hierarchical porous carbon aerogel derived from bagasse for high performance supercapacitor electrode.

    Science.gov (United States)

    Hao, Pin; Zhao, Zhenhuan; Tian, Jian; Li, Haidong; Sang, Yuanhua; Yu, Guangwei; Cai, Huaqiang; Liu, Hong; Wong, C P; Umar, Ahmad

    2014-10-21

    Renewable, cost-effective and eco-friendly electrode materials have attracted much attention in the energy conversion and storage fields. Bagasse, the waste product from sugarcane that mainly contains cellulose derivatives, can be a promising candidate to manufacture supercapacitor electrode materials. This study demonstrates the fabrication and characterization of highly porous carbon aerogels by using bagasse as a raw material. Macro and mesoporous carbon was first prepared by carbonizing the freeze-dried bagasse aerogel; consequently, microporous structure was created on the walls of the mesoporous carbon by chemical activation. Interestingly, it was observed that the specific surface area, the pore size and distribution of the hierarchical porous carbon were affected by the activation temperature. In order to evaluate the ability of the hierarchical porous carbon towards the supercapacitor electrode performance, solid state symmetric supercapacitors were assembled, and a comparable high specific capacitance of 142.1 F g(-1) at a discharge current density of 0.5 A g(-1) was demonstrated. The fabricated solid state supercapacitor displayed excellent capacitance retention of 93.9% over 5000 cycles. The high energy storage ability of the hierarchical porous carbon was attributed to the specially designed pore structures, i.e., co-existence of the micropores and mesopores. This research has demonstrated that utilization of sustainable biopolymers as the raw materials for high performance supercapacitor electrode materials is an effective way to fabricate low-cost energy storage devices.

  4. High-speed countercurrent chromatography for purification of single-walled carbon nanotubes

    Institute of Scientific and Technical Information of China (English)

    Ying Cai; Zhi Hong Yan; Ying Chun Lv; Min Zi; Li Ming Yuan

    2008-01-01

    A new chromatographic purification of single-walled carbon nanotubes using high-speed countercurrent chromatography is reported.The purification was accomplished on the basis of experiment that dispersed the single-walled carbon nanotubes with sodium dodecyl sulfate,and the result mixture was separated using the two phase system composed of n-butanol/water=1/1 (v/v).The sizes of SWNTs separated were observed by scanning electron microscopy.The results demonstrated that the high-speed countercurrent chromatography possessed a good efficency for purification of single-walled carbon nanotubes.

  5. Silicon clathrates and carbon analogs: high pressure synthesis, structure, and superconductivity.

    Science.gov (United States)

    Yamanaka, Shoji

    2010-02-28

    Compounds with cage-like structures of elemental silicon and carbon are comparatively reviewed. Barium containing silicon clathrate compounds isomorphous with type I gas hydrates were prepared using high pressure and high temperature (HPHT) conditions, and found to become superconductors. The application of HPHT conditions to Zintl binary silicides have produced a number of silicon-rich cage-like structures including new clathrate structures; most of them are superconductors. Carbon analogs of silicon clathrates can be prepared by 3D polymerization of C(60) under HPHT conditions, which are new allotropes of carbon with expanded framework structures. The crystal chemistry and characteristic properties of some related compounds are also reviewed.

  6. Goal-directed therapy improves the outcome of high-risk cardiac patients undergoing off-pump coronary artery bypass

    Directory of Open Access Journals (Sweden)

    Poonam Malhotra Kapoor

    2017-01-01

    Full Text Available Background: There has been a constant emphasis on developing management strategies to improve the outcome of high-risk cardiac patients undergoing surgical revascularization. The performance of coronary artery bypass surgery on an off-pump coronary artery bypass (OPCAB avoids the risks associated with extra-corporeal circulation. The preliminary results of goal-directed therapy (GDT for hemodynamic management of high-risk cardiac surgical patients are encouraging. The present study was conducted to study the outcome benefits with the combined use of GDT with OPCAB as compared to the conventional hemodynamic management. Material and Method: Patients with the European System for Cardiac Operative Risk Evaluation ≥3 scheduled for OPCAB were randomly divided into two groups; the control and GDT groups. The GDT group included the monitoring and optimization of advanced parameters, including cardiac index (CI, systemic vascular resistance index, oxygen delivery index, stroke volume variation; continuous central venous oxygen saturation (ScVO 2 , global end-diastolic volume, and extravascular lung water (EVLW, using FloTrac™ , PreSep™ , and EV-1000 ® monitoring panels, in addition to the conventional hemodynamic management in the control group. The hemodynamic parameters were continuously monitored for 48 h in Intensive Care Unit (ICU and corrected according to GDT protocol. A total of 163 patients consented for the study. Result: Seventy-five patients were assigned to the GDT group and 88 patients were in the control group. In view of 9 exclusions from the GDT group and 12 exclusions from control group, 66 patients in the GDT group and 76 patients in control group completed the study. Conclusion: The length of stay in hospital (LOS-H (7.42 ± 1.48 vs. 5.61 ± 1.11 days, P < 0.001 and ICU stay (4.2 ± 0.82 vs. 2.53 ± 0.56 days, P < 0.001 were significantly lower in the GDT group as compared to control group. The duration of inotropes (3.24 ± 0

  7. Design and synthesis of polymer, carbon and composite electrodes for high energy and high power supercapacitors

    Science.gov (United States)

    Arcila Velez, Margarita Rosa

    Supercapacitors (SCs) are promising energy storage devices because they deliver energy faster than Li-ion batteries and store larger amounts of charge compared to dielectric capacitors. SCs are classified in electrical double layer capacitors (EDLCs) and pseudocapacitors, based on their charge storage mechanism. EDLCs store charge electrostatically, i.e. by physical charge separation. This mechanism limits the storable amount of energy to the available surface area of the electrode, typically made of carbon materials, but grants good cycling stability of the SC device. Pseudocapacitor electrodes, commonly made of conducting polymers or metal oxides, store charge faradaically, i.e. through redox reactions throughout the bulk material, which allows them to store significantly larger amounts of energy than EDLCs, but their stability is compromised due to the partial irreversibility of the faradaic processes. To accomplish the commercialization of SCs, devices must show a combination of high charge storage capacities and long-term stability, besides being cost-effective. To tackle the current issues of SCs, this field of study has taken mainly two directions: 1) the development of new architectures and nanostructures of the active materials, which has shown to increase the surface area, enhance stability, and facilitate ion diffusion; and 2) fabrication of composites between non-faradaic (carbon), faradaic materials, and/or redox-active components to achieve a balance between the amount of energy stored and the stability. Following the first approach, a continuous process to grow vertically aligned carbon nanotubes (VACNTs) on cost-effective aluminum foil was developed. The resulting electrodes were analyzed as SC electrodes and in symmetric cells, and the influence of the arrangement of the nanotubes and the synthesis conditions was studied. The performance of the VACNTs produced continuously showed similar performance to the VACNTs produced stationarily and the

  8. High-temperature electrochemical synthesis of carbon-containing inorganic compounds under excessive carbon dioxide pressure

    Directory of Open Access Journals (Sweden)

    Novoselova I.A.

    2003-01-01

    Full Text Available Features of the electroreduction of carbon dioxide dissolved in the equimolar melt of sodium and potassium chlorides under excessive pressure of up to 1.7 MPa have been studied by cyclic voltametry over a wide polarization rate range. It has been found that the electrode process occurs in two stages at sweep rates of ≤0.1 V s-1, and its mechanism has been suggested. The cathodic product is polycrystalline graphite. Systems and conditions for producing two- and three-component refractory metal carbides using CO2 as a synthesis component have been selected.

  9. Mesoporous Nitrogen Doped Carbon-Glass Ceramic Cathode for High Performance Lithium-Oxygen Battery

    Science.gov (United States)

    2012-06-01

    Hardwick, and J.- M. Tarascon, Nature Materials, vol. 11, pp 19-29, 2012. 2. Linden , D. (Ed), Handbook of Batteries , 2nd Edition, Mc-Graw-Hill, New...AFRL-RQ-WP-TP-2015-0053 MESOPOROUS NITROGEN DOPED CARBON-GLASS CERAMIC CATHODE FOR HIGH PERFORMANCE LITHIUM-OXYGEN BATTERY (POSTPRINT...DOPED CARBON-GLASS CERAMIC CATHODE FOR HIGH PERFORMANCE LITHIUM-OXYGEN BATTERY (POSTPRINT) 5a. CONTRACT NUMBER In-house 5b. GRANT NUMBER 5c

  10. Electrochemical Performance of Highly Mesoporous Nitrogen Doped Carbon Cathode in Lithium-Oxygen Batteries (Postprint)

    Science.gov (United States)

    2011-03-01

    Chem. Lett. 1 (2010) 2193–2203. [3] F.T. Wagner, B. Lakshmanan, M.F. Mathias, J. Phys. Chem. Lett. 1 (2010) 2204–2219. [4] D. Linden (Ed.), Handbook ...AFRL-RQ-WP-TP-2015-0052 ELECTROCHEMICAL PERFORMANCE OF HIGHLY MESOPOROUS NITROGEN DOPED CARBON CATHODE IN LITHIUM-OXYGEN BATTERIES ...01 March 2011 4. TITLE AND SUBTITLE ELECTROCHEMICAL PERFORMANCE OF HIGHLY MESOPOROUS NITROGEN DOPED CARBON CATHODE IN LITHIUM-OXYGEN BATTERIES

  11. Microstructure and Property of High Carbonic-Chromium Cast Steel with Different Hot Deformation Ratio

    Institute of Scientific and Technical Information of China (English)

    XU Tao; WANG Jiu-liang; ZHANG Run-jun; CHAO Guo-hua; LIU Jian-hua

    2004-01-01

    The microstructure and properties of high carbonic-chromium cast steel subjected to different hot deformation ratios were studied. The experimental results show that the microstructure and properties of high carbonic-chromium cast steel are obviously improved after hot deformation, and the best mechanical properties of the cast steel can be obtained under hot deformation ratio of 40 %-50 %, which leads to the morphology change of eutectic carbide and the precipitation of granular carbides.

  12. Preparation of Multiwall Carbon Nanotubes-supported High Loading Platinum for Vehicular PEMFC Application

    Institute of Scientific and Technical Information of China (English)

    Bing ZHANG; Li Juan CHEN; Kai Yong GE; Yan Chuan GUO; Bi Xian PENG

    2005-01-01

    Multiwall carbon nanotube-supported Pt (Pt/MWNTs) catalysts with high dispersion and high loading of Pt were prepared by chemical reduction method and the loading of Pt got to 40wt%. The average diameter of Pt nanoparticles on MWNTs was about 3.5 nm. When the hydrogen and air were used as reactant gases for PEMFC, Pt/MWNTs catalysts showed significantly higher performance than the Pt/XC-72 (carbon black) catalysts.

  13. High-resolution annual maps of whole system mangrove carbon stocks from 2000 to 2012

    CERN Document Server

    Hamilton, Stuart E

    2016-01-01

    Mangrove forests store high densities of organic carbon compared to other forested ecosystems1. Such high carbon storage coupled with their rate of deforestation means that mangroves can contribute to global carbon emissions and are candidates for Payments for Ecosystem Services (PES) schemes. This study quantifies two important datasets required for emissions and PES reporting: 1) annual mangrove carbon stocks from 2000 to 2012 at the global, national, and sub-national level; and 2) global carbon emissions resulting from deforestation within this period. We show that mangroves stored 4.19 Pg of carbon in 2012, with Indonesia, Brazil, Malaysia, and Papua New Guinea accounting for greater than 50% of this stock. Of this 4.19 Pg, 2.96 Pg of the global carbon stock is contained within the soil and 1.23 Pg in the living biomass. Two percent of global carbon was lost between 2000 and 2012, equivalent to 316,705 tonnes of potential C02 emissions.

  14. "High or low Inferior Mesenteric Artery ligation in Laparoscopic low Anterior Resection: study protocol for a randomized controlled trial" (HIGHLOW trial).

    Science.gov (United States)

    Mari, Giulio; Maggioni, Dario; Costanzi, Andrea; Miranda, Angelo; Rigamonti, Luca; Crippa, Jacopo; Magistro, Carmelo; Di Lernia, Stefano; Forgione, Antonello; Carnevali, Pietro; Nichelatti, Michele; Carzaniga, Pierluigi; Valenti, Francesco; Rovagnati, Marco; Berselli, Mattia; Cocozza, Eugenio; Livraghi, Lorenzo; Origi, Matteo; Scandroglio, Ildo; Roscio, Francesco; De Luca, Antonio; Ferrari, Giovanni; Pugliese, Raffaele

    2015-01-27

    The position of arterial ligation during laparoscopic anterior rectal resection with total mesorectal excision can affect genito-urinary function, bowel function, oncological outcomes, and the incidence of anastomotic leakage. Ligation to the inferior mesenteric artery at the origin or preservation of the left colic artery are both widely performed in rectal surgery. The aim of this study is to compare the incidence of genito-urinary dysfunction, anastomotic leak and oncological outcomes in laparoscopic anterior rectal resection with total mesorectal excision with high or low ligation of the inferior mesenteric artery in a controlled randomized trial. The HIGHLOW study is a multicenter randomized controlled trial in which patients are randomly assigned to high or low inferior mesenteric artery ligation during laparoscopic anterior rectal resection with total mesorectal excision for rectal cancer. Inclusion criteria are middle or low rectal cancer (0 to 12 cm from the anal verge), an American Society of Anesthesiologists score of I, II, or III, and a body mass index lower than 30. The primary end-point measure is the incidence of post-operative genito-urinary dysfunction. The secondary end-point measure is the incidence of anastomotic leakage in the two groups. A total of 200 patients (100 per arm) will reliably have 84.45 power in estimating a 20% difference in the incidence of genito-urinary dysfunctions. With a group size of 100 patients per arm it is possible to find a significant difference (α = 0.05, β = 0.1555). Allowing for an estimated dropout rate of 5%, the required sample size is 212 patients. The HIGHLOW trial is a randomized multicenter controlled trial that will provide evidence on the merits of the level of arterial ligation during laparoscopic anterior rectal resection with total mesorectal excision in terms of better preserved post-operative genito-urinary function. ClinicalTrials.gov Identifier: NCT02153801 Protocol Registration Receipt 29/5/2014.

  15. Transcatheter coil embolization of an intercostal artery to pulmonary artery fistula

    Energy Technology Data Exchange (ETDEWEB)

    Cantasdemir, Murat; Kantarci, Fatih; Islak, Civan; Kocer, Naci; Numan, Furuzan [Department of Radiology, Cerrahpasa Medical Faculty, Istanbul University (Turkey); Saltuk, Levent [Institute of Cardiology, Cerrahpasa Medical Faculty, Istanbul University (Turkey)

    2002-02-01

    An 18-year-old asymptomatic male was found to have a high-flow systemic arterial to pulmonary arterial fistula fed by dilated lower intercostal arteries draining via pulmonary artery toward the left main pulmonary trunk. Transcatheter Guglielmi Detachable Coil (GDC; Target Ther, Fremont, Calif.) embolization was performed. Transcatheter embolization is a reasonable and less invasive mode in the treatment of systemic artery to pulmonary artery fistula, and GDC offers more precise coil placement over other conventional coils. (orig.)

  16. Prediction of arterial blood gas values from arterialized earlobe blood gas values in patients treated with mechanical ventilation

    Directory of Open Access Journals (Sweden)

    Honarmand Azim

    2008-01-01

    Full Text Available Background/Objective: Arterial blood gas (ABG analysis is useful in evaluation of the clinical condition of critically ill patients; however, arterial puncture or insertion of an arterial catheter may sometimes be difficult and cause many complications. Arterialized ear lobe blood samples have been described as adequate to gauge gas exchange in acute and chronically ill pediatric patients. Purpose: This study evaluates whether pH, partial pressure of oxygen (PO 2 , partial pressure of carbon dioxide (PCO 2 , base excess (BE, and bicarbonate (HCO 3 values of arterialized earlobe blood samples could accurately predict their arterial blood gas analogs for adult patients treated by mechanical ventilation in an intensive care unit (ICU. Setting: A prospective descriptive study Methods: Sixty-seven patients who were admitted to ICU and treated with mechanical ventilation were included in this study. Blood samples were drawn simultaneously from the radial artery and arterialized earlobe of each patient. Results: Regression equations and mean percentage-difference equations were derived to predict arterial pH, PCO 2 , PO 2 , BE, and HCO 3 -values from their earlobe analogs. pH, PCO 2 , BE, and HCO 3 all significantly correlated in ABG and earlobe values. In spite of a highly significant correlation, the limits of agreement between the two methods were wide for PO 2 . Regression equations for prediction of pH, PCO 2 , BE, and HCO3- values were: arterial pH (pHa = 1.81+ 0.76 x earlobe pH (pHe [r = 0.791, P < 0.001]; PaCO 2 = 1.224+ 1.058 x earlobePCO 2 (PeCO 2 [r = 0.956, P < 0.001]; arterial BE (BEa = 1.14+ 0.95 x earlobe BE (BEe [r= 0.894, P < 0.001], and arterial HCO 3 - (HCO 3 -a = 1.41+ earlobe HCO 3 (HCO 3 -e [r = 0.874, P < 0.001]. The predicted ABG values from the mean percentage-difference equations were derived as follows: pHa = pHe x 1.001; PaCO 2 = PeCO 2 x 0.33; BEa = BEe x 0.57; and HCO 3 -a = HCO 3 -e x 1.06. Conclusions: Arterialized

  17. Magnetic resonance angiography of the aortic arch and its main arteries directed to the brain with use of head neck coil. With special reference to relation between high position of the aortic arch and kinked vertebral and carotid arteries

    Energy Technology Data Exchange (ETDEWEB)

    Morita, Hitoshi [Saitama Medical School, Moroyama (Japan)

    1996-12-01

    We studied 316 individuals who requested general health examinations (March 1993 to February 1995), and who underwent blood tests, urinalysis and MRA with a head neck coil, and 25 volunteers underwent the same examinations. The head neck coil used covered the head, neck and upper thorax, and each individual coil could transmit and receive signals. Three-dimensional time of flight MRA was employed in the investigation. The saturation pulse was placed in a coronal direction behind the slab to suppress the venous inflow signals. Our results indicate that in all individuals, MRA clearly demonstrated the aorta and its main branches extending up to the circle of Willis. It was possible to rotate the reconstructed 3-D image around the body axis permitting the visualization of secondary or more peripheral branches, depending on their size and direction. The severity of V1 kinking, classified by using the modified Mets criteria, correlated well with advancing age. V1 kinking was first evident in the third decade of life, while kinking of the internal carotid artery appeared in the fourth decade. The highest level of the aortic arch was evaluated in terms of the aorto-C2 (A-C2) distance, i.e., the distance measured from the C2 level, where the vertebral artery curved laterally in the transverse foramen of C2, and the A level, where the upper margin of the aortic arch was highest. Shortening of the A-C2 distance was noted with aging, and a good correlation between increased height of the aortic arch and aging was seen. As compared to conventional contrast arteriography, MRA of the aortic arch and its branch arteries extending into the cranium does provide accurate data. A high position of the aortic arch, buckling of the great vessels, and tortuosity, kinking and coiling of the vertebral and carotid arteries are clearly shown. (K.H.)

  18. Highly energetic compositions based on functionalized carbon nanomaterials

    Science.gov (United States)

    Yan, Qi-Long; Gozin, Michael; Zhao, Feng-Qi; Cohen, Adva; Pang, Si-Ping

    2016-02-01

    In recent years, research in the field of carbon nanomaterials (CNMs), such as fullerenes, expanded graphite (EG), carbon nanotubes (CNTs), graphene, and graphene oxide (GO), has been widely used in energy storage, electronics, catalysts, and biomaterials, as well as medical applications. Regarding energy storage, one of the most important research directions is the development of CNMs as carriers of energetic components by coating or encapsulation, thus forming safer advanced nanostructures with better performances. Moreover, some CNMs can also be functionalized to become energetic additives. This review article covers updated preparation methods for the aforementioned CNMs, with a more specific orientation towards the use of these nanomaterials in energetic compositions. The effects of these functionalized CNMs on thermal decomposition, ignition, combustion and the reactivity properties of energetic compositions are significant and are discussed in detail. It has been shown that the use of functionalized CNMs in energetic compositions greatly improves their combustion performances, thermal stability and sensitivity. In particular, functionalized fullerenes, CNTs and GO are the most appropriate candidate components in nanothermites, solid propellants and gas generators, due to their superior catalytic properties as well as facile preparation methods.

  19. Middle Cerebral Artery Atherosclerotic Plaques in Recent Small Subcortical Infarction: A Three-Dimensional High-resolution MR Study

    Directory of Open Access Journals (Sweden)

    Xiao-Dong Zou

    2015-01-01

    Full Text Available Purpose. Conventional two-dimensional vessel wall imaging has been used to depict the middle cerebral artery (MCA wall in patients with recent small subcortical infarctions (RSSIs. However, its clinical use has been limited by restricted spatial coverage, low signal-to-noise ratio (SNR, and long scan time. We used a novel three-dimensional high-resolution MR imaging (3D HR-MRI technique to investigate the presence, locations, and contrast-enhanced patterns of MCA plaques and their relationship with RSSI. Methods. Nineteen consecutive patients with RSSI but no luminal stenosis on MR angiography were prospectively enrolled. 3D HR-MRI was performed using a T1w-SPACE sequence at 3.0 T. The presence, locations, and contrast-enhanced patterns of the MCA plaques on the ipsilateral and contralateral sides to the RSSI were analyzed. Results. Eighteen patients successfully completed the study. MCA atherosclerotic plaques occurred more frequently on the ipsilateral than the contralateral side to the RSSI (72.2% versus 33.3%, P=0.044. The occurrence of superiorly located plaques was significantly higher on the ipsilateral than the contralateral side of the MCA (66.7% versus 27.8%; P=0.044. Conclusions. Superiorly located plaques are closely associated with RSSI. 3D high-resolution vessel wall imaging may be a potential tool for etiologic assessment of ischemic stroke.

  20. Association of High Density Lipoprotein with Platelet to Lymphocyte and Neutrophil to Lymphocyte Ratios in Coronary Artery Disease Patients

    Directory of Open Access Journals (Sweden)

    Jayesh H. Prajapati

    2014-01-01

    Full Text Available Background. We aimed to evaluate a relationship between platelet-lymphocyte ratio (PLR and neutrophil-lymphocyte ratio (NLR with high density lipoprotein (HDL cholesterol levels in coronary artery disease (CAD patients. Methods. A total of 354 patients with angiographically confirmed coronary blockages were enrolled in the study. Hematological indices and lipid profiling data of all the patients were collected. Results. We have observed significant association between HDL and PLR (P=0.008 and NLR (P=0.009; however no significant relationship was obtained with HDL and isolated platelet (P=0.488, neutrophil (P=0.407, and lymphocyte (P=0.952 counts in CAD patients. The association was subjected to gender specific variation as in males PLR (P=0.024 and NLR (P=0.03 were highly elevated in low HDL patients, whereas in females the elevation could not reach the statistically significant level. The PLR (217.47 versus 190.3; P=0.01 and NLR (6.33 versus 5.10; P=0.01 were significantly higher among the patients with acute coronary syndrome. In young patients the PLR (P=0.007 and NLR (P=0.001 were inversely associated with HDL, whereas in older population only NLR (P=0.05 had showed a significant association. Conclusion. We conclude that PLR and NLR are significantly elevated in CAD patients having low HDL levels.

  1. Electron microscopy investigation of interface between carbon fiber and ultra high molecular weight polyethylene

    Energy Technology Data Exchange (ETDEWEB)

    Stepashkin, A.A.; Chukov, D.I., E-mail: dil_chukov@yahoo.com; Gorshenkov, M.V.; Tcherdyntsev, V.V.; Kaloshkin, S.D.

    2014-02-15

    Highlights: • Effect of the carbon fibers surface treatments on the adhesive interactions in UHMWPE composites was studied. • Air oxidation of carbon filler ensures most significant increase in adhesion interaction in UHMWPE based composites. • Nanosized UHMWPE fibers with 20–40 nm in diameter and with 6–10 μm in length, was observed on the surface of carbon fibers. -- Abstract: Scanning electron microscopy was used to investigate the surface of initial and modified high-strength and high-modulus carbon fibers as well as interfaces in the ultra high molecular weight polyethylene, filled with above-mentioned fibers. Effect of the fibers surface modifying method on the adhesive interactions in composites was studied. It was observed that interaction of matrix with a modified surface of fibers results in a formation of bonds with strength higher than the yield strength of the polymer. It results in a formation of long nanosized polymer wires at tensile fracture of composites.

  2. Nitrogen Doped Macroporous Carbon as Electrode Materials for High Capacity of Supercapacitor

    Directory of Open Access Journals (Sweden)

    Yudong Li

    2017-01-01

    Full Text Available Nitrogen doped carbon materials as electrodes of supercapacitors have attracted abundant attention. Herein, we demonstrated a method to synthesize N-doped macroporous carbon materials (NMC with continuous channels and large size pores carbonized from polyaniline using multiporous silica beads as sacrificial templates to act as electrode materials in supercapacitors. By the nice carbonized process, i.e., pre-carbonization at 400 °C and then pyrolysis at 700/800/900/1000 °C, NMC replicas with high BET specific surface areas exhibit excellent stability and recyclability as well as superb capacitance behavior (~413 F ⋅ g−1 in alkaline electrolyte. This research may provide a method to synthesize macroporous materials with continuous channels and hierarchical pores to enhance the infiltration and mass transfer not only used as electrode, but also as catalyst somewhere micro- or mesopores do not work well.

  3. An evaluation method of hydrocarbon generating potential of highly mature and over-mature marine carbonate

    Institute of Scientific and Technical Information of China (English)

    程克明; 王兆云

    1997-01-01

    How to restore the residual organic carbon and residual hydrocarbon-generating potential is discussed based on the hydrocarbon degradability of source rock. The results indicate there is linear function relationship between the restoring coefficient of residual organic carbon (Kc) and the vitrinite reflectance (Ro% ) of various kinds of source rock, but the relationship is secondary functional between the restoring coefficient of residual hydrocarbon-generating potential (Ks) and the vitrinite reflectance (R0%). It is pointed out that Kc= (1 - Dresidual)/(1-Dprimary), Xs=Kc (Dprimary/Dresidual). The restoration of residual organic carbon and hydrocarbon-gen era ting potential of the Cambrian and Ordovician highly mature marine carbonate in the Tarim Basin and North China region shows that the lower limit value of hydrocarbon generating potential and the organic matter abundance of carbonate source rock are basically the same as that of clastic rock. The technical difficulty in hydrocarbon generating eva

  4. High-flux water desalination with interfacial salt sieving effect in nanoporous carbon composite membranes

    CERN Document Server

    Chen, Wei; Zhang, Qiang; Fan, Zhongli; Huang, Kuo-Wei; Zhang, Xixiang; Lai, Zhiping; Sheng, Ping

    2016-01-01

    Nanoporous carbon composite membranes, comprising a layer of porous carbon fiber structures with an average channel width of 30-60 nm grown on a porous ceramic substrate, are found to exhibit robust desalination effect with high freshwater flux. In three different membrane processes of vacuum membrane distillation, reverse osmosis and forward osmosis, the carbon composite membrane showed 100% salt rejection with 3.5 to 20 times higher freshwater flux compared to existing polymeric membranes. Thermal accounting experiments found that at least 80% of the freshwater pass through the carbon composite membrane with no phase change. Molecular dynamics simulations revealed a unique salt rejection mechanism. When seawater is interfaced with either vapor or the surface of carbon, one to three interfacial atomic layers contain no salt ions. Below the liquid entry pressure, the salt solution is stopped at the openings to the porous channels and forms a meniscus, while the surface layer of freshwater can feed the surface...

  5. A highly permeable and enhanced surface area carbon-cloth electrode for vanadium redox flow batteries

    Science.gov (United States)

    Zhou, X. L.; Zhao, T. S.; Zeng, Y. K.; An, L.; Wei, L.

    2016-10-01

    In this work, a high-performance porous electrode, made of KOH-activated carbon-cloth, is developed for vanadium redox flow batteries (VRFBs). The macro-scale porous structure in the carbon cloth formed by weaving the carbon fibers in an ordered manner offers a low tortuosity (∼1.1) and a broad pore distribution from 5 μm to 100 μm, rendering the electrode a high hydraulic permeability and high effective ionic conductivity, which are beneficial for the electrolyte flow and ion transport through the porous electrode. The use of KOH activation method to create nano-scale pores on the carbon-fiber surfaces leads to a significant increase in the surface area for redox reactions from 2.39 m2 g-1 to 15.4 m2 g-1. The battery assembled with the present electrode delivers an energy efficiency of 80.1% and an electrolyte utilization of 74.6% at a current density of 400 mA cm-2, as opposed to an electrolyte utilization of 61.1% achieved by using a conventional carbon-paper electrode. Such a high performance is mainly attributed to the combination of the excellent mass/ion transport properties and the high surface area rendered by the present electrode. It is suggested that the KOH-activated carbon-cloth electrode is a promising candidate in redox flow batteries.

  6. Drugs targeting high-density lipoprotein cholesterol for coronary artery disease management.

    Science.gov (United States)

    Katz, Pamela M; Leiter, Lawrence A

    2012-01-01

    Many patients remain at high risk for future cardiovascular events despite levels of low-density lipoprotein cholesterol (LDL-C) at, or below, target while taking statin therapy. Much effort is therefore being focused on strategies to reduce this residual risk. High-density lipoprotein cholesterol (HDL-C) is a strong, independent, inverse predictor of coronary heart disease risk and is therefore an attractive therapeutic target. Currently available agents that raise HDL-C have only modest effects and there is limited evidence of additional cardiovascular risk reduction on top of background statin therapy associated with their use. It was hoped that the use of cholesteryl ester transfer protein (CETP) inhibitors would provide additional benefit, but the results of clinical outcome studies to date have been disappointing. The results of ongoing trials with other CETP inhibitors that raise HDL-C to a greater degree and also lower LDL-C, as well as with other emerging therapies are awaited.

  7. Toward high-performance digital logic technology with carbon nanotubes.

    Science.gov (United States)

    Tulevski, George S; Franklin, Aaron D; Frank, David; Lobez, Jose M; Cao, Qing; Park, Hongsik; Afzali, Ali; Han, Shu-Jen; Hannon, James B; Haensch, Wilfried

    2014-09-23

    The slow-down in traditional silicon complementary metal-oxide-semiconductor (CMOS) scaling (Moore's law) has created an opportunity for a disruptive innovation to bring the semiconductor industry into a postsilicon era. Due to their ultrathin body and ballistic transport, carbon nanotubes (CNTs) have the intrinsic transport and scaling properties to usher in this new era. The remaining challenges are largely materials-related and include obtaining purity levels suitable for logic technology, placement of CNTs at very tight (∼5 nm) pitch to allow for density scaling and source/drain contact scaling. This review examines the potential performance advantages of a CNT-based computing technology, outlines the remaining challenges, and describes the recent progress on these fronts. Although overcoming these issues will be challenging and will require a large, sustained effort from both industry and academia, the recent progress in the field is a cause for optimism that these materials can have an impact on future technologies.

  8. Noninvasive assessment of coronary vasodilation using cardiovascular magnetic resonance in patients at high risk for coronary artery disease

    Directory of Open Access Journals (Sweden)

    Yang Phillip

    2008-05-01

    Full Text Available Abstract Background Impaired coronary vasodilation to both endothelial-dependent and endothelial-independent stimuli have been associated with atherosclerosis. Direct measurement of coronary vasodilation using x-ray angiography or intravascular ultrasound is invasive and, thus, not appropriate for asymptomatic patients or for serial follow-up. In this study, high-resolution coronary cardiovascular magnetic resonance (CMR was used to investigate the vasodilatory response to nitroglycerine (NTG of asymptomatic patients at high risk for CAD. Methods A total of 46 asymptomatic subjects were studied: 13 high-risk patients [8 with diabetes mellitus (DM, 5 with end stage renal disease (ESRD] and 33 age-matched controls. Long-axis and cross-sectional coronary artery images were acquired pre- and 5 minutes post-sublingual NTG using a sub-mm-resolution multi-slice spiral coronary CMR sequence. Coronary cross sectional area (CSA was measured on pre- and post-NTG images and % coronary vasodilation was calculated. Results Patients with DM and ESRD had impaired coronary vasodilation to NTG compared to age-matched controls (17.8 ± 7.3% vs. 25.6 ± 7.1%, p = 0.002. This remained significant for ESRD patients alone (14.8 ± 7.7% vs. 25.6 ± 7.1%; p = 0.003 and for DM patients alone (19.8 ± 6.3% vs. 25.6 ± 7.1%; p = 0.049, with a non-significant trend toward greater impairment in the ESRD vs. DM patients (14.8 ± 7.7% vs. 19.8 ± 6.3%; p = 0.23. Conclusion Noninvasive coronary CMR demonstrates impairment of coronary vasodilation to NTG in high-risk patients with DM and ESRD. This may provide a functional indicator of subclinical atherosclerosis and warrants clinical follow up to determine prognostic significance.

  9. Effect of casting technology on microstructure and phases of high carbon high speed steel

    Directory of Open Access Journals (Sweden)

    Zhang Tianming

    2011-05-01

    Full Text Available The as-cast microstructures of high carbon high speed steels (HC-HSS made by sand casting, centrifugal casting and electromagnetic centrifugal casting, respectively, were studied by using of optical microscopy (OM and D/max2200pc X-ray diffraction. The results show that the microstructure of as-cast HC-HSS is dominated by alloy carbides (W2C, VC, Cr7C3, martensite and austenite. The centrifugal casting and electromagnetic centrifugal casting apparently improve the solidification structure of HC-HSS. With the increase of magnetic intensity (B, the volume fraction of austenite in the HC-HSS solidification structure increases significantly while the eutectic ledeburite decreases. Moreover, the secondary carbides precipitated from the austenite are finer with more homogeneous distribution in the electromagnetic centrifugal castings. It has also been found that the lath of eutectic carbide in ledeburite becomes finer and carbide phase spacing in eutectic ledeburite increases along with the higher magnetic field strength.

  10. Highly Conductive Aromatic Functionalized Multi-Walled Carbon Nanotube for Inkjet Printable High Performance Supercapacitor Electrodes.

    Directory of Open Access Journals (Sweden)

    Sanjeev K Ujjain

    Full Text Available We report the functionalization of multiwalled carbon nanotubes (MWCNT via the 1,3-dipolar [3+2] cycloaddition of aromatic azides, which resulted in a detangled CNT as shown by transmission electron microscopy (TEM. Carboxylic moieties (-COOH on aromatic azide result in highly stable aqueous dispersion (max. conc. ~ 10 mg/mL H2O, making the suitable for inkjet printing. Printed patterns on polyethylene terephthalate (PET flexible substrate exhibit low sheet resistivity ~65 Ω. cm, which is attributed to enhanced conductivity. Fabricated Supercapacitors (SC assembled using these printed substrates exhibit good electrochemical performance in organic as well as aqueous electrolytes. High energy and power density (57.8 Wh/kg and 0.85 kW/kg in 1M H2SO4 aqueous electrolyte demonstrate the excellent performance of the proposed supercapacitor. Capacitive retention varies from ~85-94% with columbic efficiency ~95% after 1000 charge/discharge cycles in different electrolytes, demonstrating the excellent potential of the device for futuristic power applications.

  11. High resolution regional soil carbon mapping in Madagascar : towards easy to update maps

    Science.gov (United States)

    Grinand, Clovis; Dessay, Nadine; Razafimbelo, Tantely; Razakamanarivo, Herintsitoaina; Albrecht, Alain; Vaudry, Romuald; Tiberghien, Matthieu; Rasamoelina, Maminiaina; Bernoux, Martial

    2013-04-01

    The soil organic carbon plays an important role in climate change regulation through carbon emissions and sequestration due to land use changes, notably tropical deforestation. Monitoring soil carbon emissions from shifting-cultivation requires to evaluate the amount of carbon stored at plot scale with a sufficient level of accuracy to be able to detect changes. The objective of this work was to map soil carbon stocks (30 cm and 100 cm depths) for different land use at regional scale using high resolution satellite dataset. The Andohahela National Parc and its surroundings (South-Est Madagascar) - a region with the largest deforestation rate in the country - was selected as a pilot area for the development of the methodology. A three steps approach was set up: (i) carbon inventory using mid infra-red spectroscopy and stock calculation, (ii) spatial data processing and (iii) modeling and mapping. Soil spectroscopy was successfully used for measuring organic carbon in this region. The results show that Random Forest was the inference model that produced the best estimates on calibration and validation datasets. By using a simple and robust method, we estimated uncertainty levels of of 35% and 43% for 30-cm and 100-cm carbon maps respectively. The approach developed in this study was based on open data and open source software that can be easily replicated to other regions and for other time periods using updated satellite images.

  12. Hybrid carbon nanoparticles modified core-shell silica: a high efficiency carbon-based phase for hydrophilic interaction liquid chromatography.

    Science.gov (United States)

    Ibrahim, Mohammed E A; Wahab, M Farooq; Lucy, Charles A

    2014-04-11

    Hydrophilic interaction liquid chromatography (HILIC) is a fast growing separation technique for hydrophilic and polar analytes. In this work, we combine the unique selectivity of carbon surfaces with the high efficiency of core-shell silica. First, 5 μm core-shell silica is electrostatically coated with 105 nm cationic latex bearing quaternary ammonium groups. Then 50 nm anionic carbon nanoparticles are anchored onto the surface of the latex coated core-shell silica particles to produce a hybrid carbon-silica phase. The hybrid phase shows different selectivity than ten previously classified HILIC column chemistries and 36 stationary phases. The hybrid HILIC phase has shape selectivity for positional isomeric pairs (phthalic/isophthalic and 1-naphthoic/2-naphthoic acids). Fast and high efficiency HILIC separations of biologically important carboxylates, phenols and pharmaceuticals are reported with efficiencies up to 85,000 plates m(-1). Reduced plate height of 1.9 (95,000 plates m(-1)) can be achieved. The hybrid phase is stable for at least 3 months of usage and storage under typical HILIC eluents.

  13. Effect of High-Calcium Diet on Coronary Artery Disease in Ossabaw Miniature Swine With Metabolic Syndrome

    OpenAIRE

    Phillips-Eakley, Alyssa K; McKenney-Drake, Mikaela L; Bahls, Martin; Newcomer, Sean C; Radcliffe, John S.; Wastney, Meryl E; Van Alstine, William G; Jackson, George; Alloosh, Mouhamad; Martin, Berdine R.; Sturek, Michael; Weaver, Connie M.

    2015-01-01

    Background Calcium is a shortfall essential nutrient that has been a mainstay of osteoporosis management. Recent and limited findings have prompted concern about the contribution of calcium supplementation to cardiovascular risk. A proposed mechanism is through the acceleration of coronary artery calcification. Determining causality between calcium intake and coronary artery calcification has been hindered by a lack of sensitive methodology to monitor early vascular calcium accumulation. The ...

  14. Nitrogen-doped porous carbon derived from biomass waste for high-performance supercapacitor.

    Science.gov (United States)

    Ma, Guofu; Yang, Qian; Sun, Kanjun; Peng, Hui; Ran, Feitian; Zhao, Xiaolong; Lei, Ziqiang

    2015-12-01

    High capacitance property and low cost are the pivotal requirements for practical application of supercapacitor. In this paper, a low cost and high capacitance property nitrogen-doped porous carbon with high specific capacitance is prepared. The as-prepared nitrogen-doped porous carbon employing potato waste residue (PWR) as the carbon source, zinc chloride (ZnCl2) as the activating agent and melamine as nitrogen doping agent. The morphology and structure of the carbon materials are studied by scanning electron microscopy (SEM), N2 adsorption/desorption, X-ray diffraction (XRD) and Raman spectra. The surface area of the nitrogen-doped carbon which prepared under 700°C is found to be 1052m(2)/g, and the specific capacitance as high as 255Fg(-1) in 2M KOH electrolyte is obtained utilize the carbon as electrode materials. The electrode materials also show excellent cyclability with 93.7% coulombic efficiency at 5Ag(-1) current density of for 5000cycles.

  15. High molecule compound synthesis from carbon dioxide; Nisanka tanso karano kobunshi gosei

    Energy Technology Data Exchange (ETDEWEB)

    Mishima, K. [Fukuoka Univ., Fukuoka (Japan)

    2000-09-05

    Recently, synthesis of organic substances and high molecule compounds using carbon dioxide of liquid or supercritical state as raw material is paid attention so as the influential means to realize the green chemistry. A zinc based catalyst which could synthesize the activated copolymer from oxidized cyclohexane and carbon dioxide was developed by Coates, Beckman et al. The high-activated fluoridation zinc based catalyst which dissolved the high-pressure carbon dioxide was developed by Beckman, etc. The possibility of the manufacturing of the high molecule copolymer which is made from carbon dioxide and oxidized cyclohexane as a raw material was shown by an appearance of this catalyst. In addition, a synthesizing method of lactone from carbon dioxide and olefinic hydrocarbon is being examined by Beckman. If this method is used practically, the manufacturing of a gentle biodegradable polymer in the environment which is made from carbon dioxide as a raw material becomes also possible. However, adequate catalysts are necessary so that this reaction may progress. (NEDO)

  16. Carbon assimilation in Eucalyptus urophylla grown under high atmospheric CO2 concentrations: A proteomics perspective.

    Science.gov (United States)

    Santos, Bruna Marques Dos; Balbuena, Tiago Santana

    2017-01-06

    Photosynthetic organisms may be drastically affected by the future climate projections of a considerable increase in CO2 concentrations. Growth under a high concentration of CO2 could stimulate carbon assimilation-especially in C3-type plants. We used a proteomics approach to test the hypothesis of an increase in the abundance of the enzymes involved in carbon assimilation in Eucalyptus urophylla plants grown under conditions of high atmospheric CO2. Our strategy allowed the profiling of all Calvin-Benson cycle enzymes and associated protein species. Among the 816 isolated proteins, those involved in carbon fixation were found to be the most abundant ones. An increase in the abundance of six key enzymes out of the eleven core enzymes involved in carbon fixation was detected in plants grown at a high CO2 concentration. Proteome changes were corroborated by the detection of a decrease in the stomatal aperture and in the vascular bundle area in Eucalyptus urophylla plantlets grown in an environment of high atmospheric CO2. Our proteomics approach indicates a positive metabolic response regarding carbon fixation in a CO2-enriched atmosphere. The slight but significant increase in the abundance of the Calvin enzymes suggests that stomatal closure did not prevent an increase in the carbon assimilation rates.

  17. Economic Evaluations for the Carbon Dioxide-involved Production of High-value Chemicals

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Ji Hyun; Lee, Dong Woog; Jang, Se Gyu; Kwak, No-Sang; Lee, In Young; Jang, Kyung Ryoung; Shim, Jae-Goo [KEPCO Research Institute, Daejon (Korea, Republic of); Choi, Jong Shin [Korea East-West Power Co. LTD, Seoul (Korea, Republic of)

    2014-06-15

    Economic evaluation of the manufacturing technology of high-value chemicals through the carbonation reaction of carbon dioxide contained in the flue gas was performed, and analysis of the IRR (Internal Rate of Return) and whole profit along the production plan of the final product was conducted. Through a carbonation reaction with sodium hydroxide that is generated from electrolysis and by using carbon dioxide in the combustion gas that is generated in the power plant, it is possible to get a high value products such as sodium bicarbonate compound and also to reduce the carbon dioxide emission simultaneously. The IRR (Internal Rate of Return) and NPV (Net Present Value) methods were used for the economic evaluation of the process which could handle carbon dioxide of 100 tons per day in the period of the 20 years of plant operation. The results of economic evaluation showed that the IRR of baseline case of technology was 67.2% and the profit that obtained during the whole operation period (20 years) was 346,922 million won based on NPV value. When considering ETS due to the emissions trading enforcement that will be activated in 2015, the NPV was improved to a 6,000 million won. Based on this results, it could be concluded that this CO2 carbonation technology is an cost-effective technology option for the reduction of greenhouse gas.

  18. Carbon nanotube network film directly grown on carbon cloth for high-performance solid-state flexible supercapacitors

    Science.gov (United States)

    Zhou, Cheng; Liu, Jinping

    2014-01-01

    Carbon nanotubes (CNTs) have received increasing attention as electrode materials for high-performance supercapacitors. We herein present a straightforward method to synthesize CNT films directly on carbon cloths as electrodes for all-solid-state flexible supercapacitors (AFSCs). The as-made highly conductive electrodes possess a three-dimensional (3D) network architecture for fast ion diffusion and good flexibility, leading to an AFSC with a specific capacitance of 106.1 F g-1, an areal capacitance of 38.75 mF cm-2, an ultralong cycle life of 100 000 times (capacitance retention: 99%), a good rate capability (can scan at 1000 mV s-1, at which the capacitance is still ˜37.8% of that at 5 mV s-1), a high energy density (2.4 μW h cm-2) and a high power density (19 mW cm-2). Moreover, our AFSC maintains excellent electrochemical attributes even with serious shape deformation (bending, folding, etc), high mechanical pressure (63 kPa) and a wide temperature window (up to 100 ° C). After charging for only 5 s, three such AFSC devices connected in series can efficiently power a red round LED for 60 s. Our work could pave the way for the design of practical AFSCs, which are expected to be used for various flexible portable/wearable electronic devices in the future.

  19. Biochemical characterization of blood plasma of coronary artery disease patients by in vitro high-resolution proton NMR spectroscopy

    Indian Academy of Sciences (India)

    Anu Malik; Uma Sharma; R Lakshmy; Rajiv Narang; Naranamanglam R Jagannathan

    2015-03-01

    This study aimed to investigate the biochemical profile of blood plasma of patients with coronary artery disease (CAD) and angiographically normal subjects (controls) to determine biomarkers for their differentiation. In this double blind study, 5 mL venous blood was drawn before angiography from CAD patients (n=60) and controls (n=13) comprising angiography normal individuals. In vitro high-resolution NMR spectroscopy of these blood plasma samples was carried out at 400 MHz, and intensity data were analysed with partial least square discriminant analysis. Categorization of subjects as controls or CAD patients and the patients further as single vessel disease (SVD), double vessel disease (DVD) and triple vessel disease (TVD) was done at the end of the study based on their angiography reports. Raised levels of lipids, alanine (Ala) and isoleucine/leucine/valine (Ile/Leu/Val) were observed in CAD patients compared with controls. Partial least square discriminant analysis showed separation between controls vs CAD patients. TVD patients showed increased levels of Ile/Leu/Val and Ala compared with controls and SVD. Alanine, Ile/Leu/Val, and LDL/VLDL appear as possible biomarkers for distinguishing between controls and patients with SVD and TVD. A metabolic adaptation of myocardium may play a role in raising the Ala level.

  20. Real-Time 12-Lead High-Frequency QRS Electrocardiography for Enhanced Detection of Myocardial Ischemia and Coronary Artery Disease

    Science.gov (United States)

    Schlegel, Todd T.; Kulecz, Walter B.; DePalma, Jude L.; Feiveson, Alan H.; Wilson, John S.; Rahman, M. Atiar; Bungo, Michael W.

    2004-01-01

    Several studies have shown that diminution of the high-frequency (HF; 150-250 Hz) components present within the central portion of the QRS complex of an electrocardiogram (ECG) is a more sensitive indicator for the presence of myocardial ischemia than are changes in the ST segments of the conventional low-frequency ECG. However, until now, no device has been capable of displaying, in real time on a beat-to-beat basis, changes in these HF QRS ECG components in a continuously monitored patient. Although several software programs have been designed to acquire the HF components over the entire QRS interval, such programs have involved laborious off-line calculations and postprocessing, limiting their clinical utility. We describe a personal computer-based ECG software program developed recently at the National Aeronautics and Space Administration (NASA) that acquires, analyzes, and displays HF QRS components in each of the 12 conventional ECG leads in real time. The system also updates these signals and their related derived parameters in real time on a beat-to-beat basis for any chosen monitoring period and simultaneously displays the diagnostic information from the conventional (low-frequency) 12-lead ECG. The real-time NASA HF QRS ECG software is being evaluated currently in multiple clinical settings in North America. We describe its potential usefulness in the diagnosis of myocardial ischemia and coronary artery disease.

  1. Realization of High-temperature Superconductivity in Nano-carbon Materials and Its Application

    Science.gov (United States)

    2015-07-13

    hottest topics in condensed matter physics and also for application to zero- emission energy system. In particular, carbon-based superconductors have...nano- carbon materials and its application II 5a. CONTRACT NUMBER FA2386-13-1-4059 5b. GRANT NUMBER Grant 13RSZ067_134059 5c. PROGRAM ELEMENT...for AOARD Grant F A2386-13- l-4059 "Realization of high-temperature superconductivity in nano-carbon materials and its application " Date: 07/13

  2. Preparation and hydrogen storage capacity of highly porous activated carbon materials derived from polythiophene

    OpenAIRE

    2011-01-01

    [EN] Highly porous carbons have been successfully synthesized by chemical activation of polythiophene with KOH. The activation process was performed under relatively mild activation conditions, i. e., a KOH/polymer weight ratio of 2 and reaction temperatures in the 600–850 °C range. The porous carbons thus obtained possess very large surface areas, up to 3000 m2/g, and pore volumes of up to 1.75 cm3/g. The pore size distribution of these carbons can be tuned via modification of the activation...

  3. High-Throughput Screening of the Asymmetric Decarboxylative Alkylation Reaction of Enolate-Stabilized Enol Carbonates

    KAUST Repository

    Stoltz, Brian

    2010-06-14

    The use of high-throughput screening allowed for the optimization of reaction conditions for the palladium-catalyzed asymmetric decarboxylative alkylation reaction of enolate-stabilized enol carbonates. Changing to a non-polar reaction solvent and to an electron-deficient PHOX derivative as ligand from our standard reaction conditions improved the enantioselectivity for the alkylation of a ketal-protected,1,3-diketone-derived enol carbonate from 28% ee to 84% ee. Similar improvements in enantioselectivity were seen for a β-keto-ester derived- and an α-phenyl cyclohexanone-derived enol carbonate.

  4. High-Throughput Screening of the Asymmetric Decarboxylative Alkylation Reaction of Enolate-Stabilized Enol Carbonates.

    Science.gov (United States)

    McDougal, Nolan T; Virgil, Scott C; Stoltz, Brian M

    2010-01-01

    The use of high-throughput screening allowed for the optimization of reaction conditions for the palladium-catalyzed asymmetric decarboxylative alkylation reaction of enolate-stabilized enol carbonates. Changing to a non-polar reaction solvent and to an electron-deficient PHOX derivative as ligand from our standard reaction conditions improved the enantioselectivity for the alkylation of a ketal-protected,1,3-diketone-derived enol carbonate from 28% ee to 84% ee. Similar improvements in enantioselectivity were seen for a β-keto-ester derived- and an α-phenyl cyclohexanone-derived enol carbonate.

  5. Effects of the transcutaneous electrode temperature on the accuracy of transcutaneous carbon dioxide tension

    DEFF Research Database (Denmark)

    Sørensen, Line C; Brage-Andersen, Lene; Greisen, Gorm

    2011-01-01

    The harmful effect of hypocapnia on the neonatal brain emphasizes the importance of monitoring arterial carbon dioxide tension (PaCO2). Transcutaneous monitoring of carbon dioxide (tcPCO2) reduces the need for arterial blood sampling. Drawbacks are high electrode temperature causing risks of skin...... burning. The aim was to determine the accuracy and precision of tcPCO2 at reduced electrode temperature....

  6. Pharmacodynamic effects of standard dose prasugrel versus high dose clopidogrel in non-diabetic obese patients with coronary artery disease.

    Science.gov (United States)

    Darlington, Andrew; Tello-Montoliu, Antonio; Rollini, Fabiana; Ueno, Masafumi; Ferreiro, José Luis; Patel, Ronakkumar; Desai, Bhaloo; Guzman, Luis A; Bass, Theodore A; Angiolillo, Dominick J

    2014-02-01

    Increased body weight is independently associated with impaired clopidogrel pharmacodynamic (PD) response. Prasugrel has more potent PD effects compared with clopidogrel, although its PD effects in obese patients are unknown. The aim of this prospective, randomised, study was to compare the PD effects of standard-dose prasugrel [60 mg loading dose (LD)/10 mg daily maintenance dose (MD)] with high-dose clopidogrel (900 mg LD/150 mg daily MD) in non-diabetic obese [body mass index (BMI) ≥30 kg/m²] patients, with coronary artery disease (CAD) on aspirin therapy. PD assessments (baseline, 2 hours post-LD and 6 ± 2 days after MD) were conducted using four platelet function assays, and the platelet reactivity index (PRI) assessed by VASP was used for sample size estimation. A total of 42 patients with a BMI of 36.42 ± 5.6 kg/m² completed the study. There were no differences in baseline PD measures between groups. At 2 hours post-LD, prasugrel was associated with lower PRI compared with clopidogrel (24.3 ± 5.5 vs 58.7 ± 5.7, p≤0.001), with consistent findings for all assays. At one-week, PRI values on prasugrel MD were lower than clopidogrel MD without reaching statistical significance (34.7 ± 5.8 vs 42.9 ± 5.8, p=0.32), with consistent findings for all assays. Accordingly, rates of high on-treatment platelet reactivity were markedly reduced after prasugrel LD, but not after MD. In conclusion, in non-diabetic obese patients with CAD, standard prasugrel dosing achieved more potent PD effects than high-dose clopidogrel in the acute phase of treatment, but this was not sustained during maintenance phase treatment. Whether an intensified prasugrel regimen is required in obese patients warrants investigation.

  7. Nanoporous Activated Carbon Derived from Rice Husk for High Performance Supercapacitor

    Directory of Open Access Journals (Sweden)

    Huaxing Xu

    2014-01-01

    Full Text Available Nanoporous activated carbon material was produced from the waste rice husks (RHs by precarbonizing RHs and activating with KOH. The morphology, structure, and specific surface area were investigated. The nanoporous carbon has the average pore size of 2.2 nm and high specific area of 2523.4 m2 g−1. The specific capacitance of the nanoporous carbon is calculated to be 250 F g−1 at the current density of 1 A g−1 and remains 80% for 198 F g−1 at the current density of 20 A g−1. The nanoporous carbon electrode exhibits long-term cycle life and could keep stable capacitance till 10,000 cycles. The consistently high specific capacitance, rate capacity, and long-term cycle life ability makes it a potential candidate as electrode material for supercapacitor.

  8. The High Resolution Transmission Electron Microscopy: A Powerful Tool for Studying the Organization of Terrestrial and Extra-Terrestrial Carbons

    Science.gov (United States)

    Rouzaud, J.-N.; Skrzypczak, A.; Bonal, L.; Derenne, S.; Quirico, E.; Robert, F.

    2005-03-01

    High Resolution Transmission Electron Microscopy (HRTEM) makes possible the imaging of the profile of the polyaromatic layers, allowing a knowledge of carbons, such as disordered natural carbons from meteorites and from Precambrian metasediments

  9. Fabrication of Highly Stable and Efficient PtCu Alloy Nanoparticles on Highly Porous Carbon for Direct Methanol Fuel Cells.

    Science.gov (United States)

    Khan, Inayat Ali; Qian, Yuhong; Badshah, Amin; Zhao, Dan; Nadeem, Muhammad Arif

    2016-08-17

    Boosting the durability of Pt nanoparticles by controlling the composition and morphology is extremely important for fuel cells commercialization. We deposit the Pt-Cu alloy nanoparticles over high surface area carbon in different metallic molar ratios and optimize the conditions to achieve desired material. The novel bimetallic electro-catalyst {Pt-Cu/PC-950 (15:15%)} offers exceptional electrocatalytic activity when tested for both oxygen reduction reaction and methanol oxidation reactions. A high mass activity of 0.043 mA/μgPt (based on Pt mass) is recorded for ORR. An outstanding longevity of this electro-catalyst is noticed when compared to 20 wt % Pt loaded either on PC-950 or commercial carbon. The high surface area carbon support offers enhanced activity and prevents the nanoparticles from agglomeration, migration, and dissolution as evident by TEM analysis.

  10. Collimated Propagation of Fast Electron Beams Accelerated by High-Contrast Laser Pulses in Highly Resistive Shocked Carbon

    Science.gov (United States)

    Vaisseau, X.; Morace, A.; Touati, M.; Nakatsutsumi, M.; Baton, S. D.; Hulin, S.; Nicolaï, Ph.; Nuter, R.; Batani, D.; Beg, F. N.; Breil, J.; Fedosejevs, R.; Feugeas, J.-L.; Forestier-Colleoni, P.; Fourment, C.; Fujioka, S.; Giuffrida, L.; Kerr, S.; McLean, H. S.; Sawada, H.; Tikhonchuk, V. T.; Santos, J. J.

    2017-05-01

    Collimated transport of ultrahigh intensity electron current was observed in cold and in laser-shocked vitreous carbon, in agreement with simulation predictions. The fast electron beams were created by coupling high-intensity and high-contrast laser pulses onto copper-coated cones drilled into the carbon samples. The guiding mechanism—observed only for times before the shock breakout at the inner cone tip—is due to self-generated resistive magnetic fields of ˜0.5 - 1 kT arising from the intense currents of fast electrons in vitreous carbon, by virtue of its specific high resistivity over the range of explored background temperatures. The spatial distribution of the electron beams, injected through the samples at different stages of compression, was characterized by side-on imaging of hard x-ray fluorescence.

  11. Polarimetric studies of carbon stars at high Galactic latitude

    CERN Document Server

    Goswami, Aruna

    2012-01-01

    Very little is known about the polarimetric properties of CH stars and carbon-enhanced metal-poor (CEMP) stars, although many of these objects have been studied in detail both photometrically and spectroscopically. We aim to derive polarimetric properties for a large sample of CEMP stars and CH stars to fill this gap. Multiband polarimetric observations were conducted in the first run for a sample of twenty-nine objects that include twenty-two CEMP and CH stars and seven polarization standards. Estimates of polarization were obtained using standard procedures of polarization calculation. Five objects in our sample do not show any significant polarization over the different colours of BVRI. For the rest of the objects the derived percentage polarization estimates are less than or equal to 1%, and they are found to exhibit random behaviour with respect to the inverse of the effective wavelength of observations. Polarization also does not seem to have any correlation with the effective temperatures of the stars....

  12. STRATEGIES AND TECHNOLOGY FOR MANAGING HIGH-CARBON ASH

    Energy Technology Data Exchange (ETDEWEB)

    Robert Hurt; Eric Suuberg; John Veranth; Xu Chen; Indrek Kulaots

    2004-02-13

    The overall objective of the present project was to identify and assess strategies and solutions for the management of industry problems related to carbon in ash. Specific issues addressed included: (1) the effect of parent fuel selection on ash properties and adsorptivity, including a first ever examination of the air entrainment behavior of ashes from alternative (non-coal) fuels; (2) the effect of various low-NOx firing modes on ash properties and adsorptivity based on pilot-plant studies; and (3) the kinetics and mechanism of ash ozonation. This laboratory data has provided scientific and engineering support and underpinning for parallel process development activities. The development work on the ash ozonation process has now transitioned into a scale-up and commercialization project involving a multi-industry team and scheduled to begin in 2004. This report describes and documents the laboratory and pilot-scale work in the above three areas done at Brown University and the University of Utah during this three-year project.

  13. Stability of Conductive Carbon Additives for High-voltage Li-ion Battery Cathodes

    OpenAIRE

    Nilssen, Benedicte Eikeland

    2014-01-01

    Conductive carbon additives are important constituents of the current state-of-the-art Li-ion battery cathodes, as the traditional active cathode materials are characterized by too low electronic conductivities. In high-voltage Li-ion batteries, these additives are subject for anion intercalation and electrolyte oxidation, which might cause changes in the conductive carbon network in the cathode, and hence the overall cycling performance of the electrode. This thesis has focused on study the ...

  14. THE SODIUM PREVALENCE IN CARBONATED SOFT DRINKS SOLD IN BRAZIL

    OpenAIRE

    Sandra Fernanda Nunes; Sonia Maria Freire; Maria Margarida Castel-Branco; Isabel Vitória Figueiredo

    2012-01-01

    The carbonated soft drinks intake has changed the children eating habits. This factor may be directly associated with arterial hypertension due the high consumption of sodium present in foods and drinks industrialized. This study was to compare sodium levels between two different types of carbonated soft drinks, carbonated sugar drinks and diet drinks to define what type of drink has the lowest sodium content and alerting healthcare professionals about the presence of sodium in industrialized...

  15. Arterial enhancement at abdominal CT angiography: Low- versus high-osmolality contrast media

    Energy Technology Data Exchange (ETDEWEB)

    Rouviere, O.; Berger, P.; Pangaud, C.; Lyonnet, D. [Hopital E. Herriot, Lyon (France). Dept. of Vascular and Genitourinary Radiology; Ecochard, R. [Hospices Civils de Lyon (France). Dept of Biostatistics; Fontaine, B. [Laboratoire Guerbet, Roissy (France)

    2000-09-01

    Purpose: To evaluate the effects of contrast media pharmokinetic differences on aortic enhancement at abdominal CT angiography and to determine whether these effects are of clinical relevance. Material and Methods: Two hundred and twelve patients referred for abdominal CT angiography were included in the study. All abdominal CT angiograms were performed with the same parameters (collimation 3 mm, pitch ratio 1.7, scan delay 30 s) after i.v. injection of 120 ml of contrast medium at 3 ml/s. After randomization, patients received either iobitridol 300 (low-osmolar, 300 mg I/ml), iobitridol 350 (low-osmolar, 350 mg I/ml) or ioxithalamate 350 (high-osmolar, 350 mg I/ml). The time attenuation curves obtained with the three contrast media were compared. Results: The time attenuation curve obtained with ioxithalamate 350 was not parallel to those obtained with iobitridol 300 and iobitridol 350. Mean peak enhancements obtained with iobitridol 350 and ioxithalamate 350 were not significantly different but iobitridol 350 provided higher mean peak enhancement than iobitridol 300. Mean delays of the peak enhancements were the same with the three contrast media. After peak enhancement, the decrease of aortic opacification under a selected threshold of 200 HU was significantly slower with iobitridol 350 than with iobitridol 300 and ioxithalamate 350, whereas iobitridol 300 and ioxithalamate 350 showed no significant differences. Conclusion: For a given iodine concentration, low-osmolality contrast media provide longer aortic opacification and may be recommended for CT angiography when long acquisition times are needed.

  16. High Per formance and Flexible Supercapacitors based on Carbonized Bamboo Fibers for Wide Temperature Applications

    Science.gov (United States)

    Zequine, Camila; Ranaweera, C. K.; Wang, Z.; Singh, Sweta; Tripathi, Prashant; Srivastava, O. N.; Gupta, Bipin Kumar; Ramasamy, K.; Kahol, P. K.; Dvornic, P. R.; Gupta, Ram K.

    2016-08-01

    High performance carbonized bamboo fibers were synthesized for a wide range of temperature dependent energy storage applications. The structural and electrochemical properties of the carbonized bamboo fibers were studied for flexible supercapacitor applications. The galvanostatic charge-discharge studies on carbonized fibers exhibited specific capacity of ~510F/g at 0.4 A/g with energy density of 54 Wh/kg. Interestingly, the carbonized bamboo fibers displayed excellent charge storage stability without any appreciable degradation in charge storage capacity over 5,000 charge-discharge cycles. The symmetrical supercapacitor device fabricated using these carbonized bamboo fibers exhibited an areal capacitance of ~1.55 F/cm2 at room temperature. In addition to high charge storage capacity and cyclic stability, the device showed excellent flexibility without any degradation to charge storage capacity on bending the electrode. The performance of the supercapacitor device exhibited ~65% improvement at 70 °C compare to that at 10 °C. Our studies suggest that carbonized bamboo fibers are promising candidates for stable, high performance and flexible supercapacitor devices.

  17. Heritabilities and genetic correlations of pulmonary arterial pressure and performance traits in Angus cattle at high altitude.

    Science.gov (United States)

    Crawford, N F; Thomas, M G; Holt, T N; Speidel, S E; Enns, R M

    2016-11-01

    Pulmonary arterial pressure (PAP) is an indicator trait for pulmonary hypertension and for the risk of developing high-altitude disease (HAD) in cattle. Pulmonary arterial pressures provide a tool for selection of breeding cattle for tolerance to high altitude in mountainous regions of the United States. The objective of this study was to evaluate relationships between growth performance traits and yearling PAP (42.4 ± 9.9 mmHg; = 5,776; elevation 2,150 m) using data from 1993 to 2014 in the John E. Rouse Colorado State University Beef Improvement Center (CSU-BIC) Angus herd. The breeding program used sires ( = 299) from both low- and high-elevation environments. We hypothesized that little to no genetic relationship exists between PAP and birth weight (BWT; direct and maternal), weaning weight (WW; direct and maternal), yearling weight (YW; direct and maternal), and postweaning gain (PWG). Historic selection of natural service sires from within the herd required a PAP of ≤ 42 mmHg. Outside AI sires ( = 156) used in this breeding program were not PAP tested and therefore were used with little knowledge of these sires' high-altitude adaptability. Performance traits (± SD) routinely recorded included BWT (36.2 ± 5.1 kg; = 8,695), WW (213.5 ± 31.8 kg; = 8,010), YW (345.6 ± 83.8 kg; = 5,580), and PWG (122.0 ± 63.7 kg; = 5,449), where PWG represented the total weight gained from weaning to yearling age. Four-trait analyses using REML were conducted with an animal model. The heritability estimates (± SE) for PAP (0.26 ± 0.03), BWT direct (0.42 ± 0.04) and maternal (0.14 ± 0.02), WW direct (0.29 ± 0.04) and maternal (0.19 ± 0.03), YW direct (0.45 ± 0.04) and maternal (0.23 ± 0.03), and PWG (0.14 ± 0.02) were in the range of those reported in previous literature. Estimates of genetic correlations (± SE) revealed weak relationships between PAP and direct and maternal BWT, direct and maternal WW, direct and maternal YW, and PWG of 0.15 ± 0.09, 0.14 ± 0

  18. To assess the intimal thickness, flow velocities, and luminal diameter of carotid arteries using high-resolution B-mode ultrasound doppler imaging

    Science.gov (United States)

    Vemuru, Madhuri; Jabbar, Afzal; Chandra, Suman

    2004-04-01

    Carotid imaging is a Gold Standard test that provides useful information about the structure and functions of carotid arteries. Spectral imaging helps to evaluate the vessel and hemodynamic changes. High resolution B-mode imaging has emerged as one of the methods of choice for determining the anatomic extent of atherosclerosis and its progression and for assessing cardiovascular risks. The measurements made with Doppler correlate well with pathologic measurements. Recent prospective studies have clearly demonstrated that these measurements of carotid intimal thickness are potent predictors of Myocardial Infarction and Stroke. This method appears very attractive as it is non-invasive, extremely safe, well accepted by the patient and relatively inexpensive. It can be performed serially and has the advantage of visualizing the arterial wall in contrast to angiographic techniques which provide only an outline of the arterial lumen. Recently, there has been an interest in the clinical use of this technique in making difficult clinical decisions like deciding on preventive therapies. 30 subjects aged 21-60 years and 30 subjects aged 61-85 years of both sexes are selected after doing a baseline study to exclude Hypertension, Diabetes, Obesity and Hyperlipidemia. The carotid arteries were examined for intimal thickening, blood flow velocities and luminal diameter. With aging there is a narrowing of the carotid vessels and significant increase in intimal thickening with a consequent increase in the blood flow velocities. Inter-observer, intra-observer and instrument variations are seen and there is no significant change in the values when the distal flow pattern is considered for measurements. Aging produces major cardiovascular changes including decreased elasticity and compliance of great arteries leading to structural and functional alterations in heart and vessels. With aging there is increased intimal thickness and increased pulse wave velocity which is clearly

  19. Short-Term Therapy with High Dose Atorvastatin in Patients with Coronary Artery Disease Can Reduce Inflammatory Process

    Directory of Open Access Journals (Sweden)

    Vida Nesar Hossein

    2010-08-01

    Full Text Available Coronary heart disease is the leading cause of death and disability in adults. The association between acute coronary syndrom (ACS and elevated serum high sensitivity c-reactive protein (hsCRP suggests that chronic inflammation of the coronary arterial wall may play an important role. A number of drugs used in the treatment of cardiovascular disease reduce serum CRP. It* is therefore possible that reduced inflammation contributes to the beneficial effects of these medications. This was a double blind randomized clinical trial on 52 patients were admitted because of ACS at the Mazandaran Heart Center, Iran in 2007. The patients were divided to three randomized groups which received 20, 40, 80* mg Atorvastatin daily for 6 months. At the time of study enrollment and 1, 3 and 6 months after initiation hsCRP were measured. 1 and 3 month after 20mg atorvastatin therapy the median serum concentration of hsCRP did not decrease significantly, but at the end of 6th month it was* significant difference. At 40mg dosage from 3th month to 6th month versus 1st month to 3th month it was significant decrease, at the end of 1th month and 3rd month it was not significant. At 80mg dose at the end of 1th month it was not significant but at the* end of 3th month and end of 6th month it was significant. Intensive lipid-lowering therapy with high-dose atorvastatin therapy relative to moderate lipid-lowering therapy with low-dose atorvastatin reduces hsCRP better. We found that treatment with greater dose of atorvastatin might decrease greater in plasma level of hsCRP.

  20. Scan-Rescan Reproducibility of High Resolution Magnetic Resonance Imaging of Atherosclerotic Plaque in the Middle Cerebral Artery.

    Directory of Open Access Journals (Sweden)

    Xuefeng Zhang

    Full Text Available To evaluate the scan-rescan reproducibility of high-resolution magnetic resonance imaging (MRI of middle cerebral artery (MCA plaque, and calculate the number of subjects needed for future longitudinal clinical studies.Twenty two patients with MCA plaque were scanned twice by a T2-weighted fast-spin-echo sequence at 3T. Areas and volumes of MCA lumen, total vessel and plaque were quantified and compared between two repeated scans. Agreement and measurement error was quantified by intraclass correlation coefficient (ICC and coefficient of variance (CV as defined by standard deviation (SD of pair wise difference / mean. Sample size needed to detect 5% to 20% changes in area/volume was calculated using 80% power and 5% significance level.There was no significant different between the area and volume measurements of two repeated scans (p>0.05 with good agreement (ICC range 0.97-0.98 for area and 0.99 for volume. Relatively small measurement errors were observed with CVs range 6.1%-11.8% for area quantification and 4.9%-8.0% for volume quantification. Volume measurements tended to have 19.7% to 32.2% smaller CVs compared with area measurements. Sample size calculation showed a group of 47 patients was sufficient to detect 5% to 10% changes in MCA area/volume.High resolution MRI is feasible for quantifying intracranial plaque area and volume in longitudinal clinical studies with low scan-rescan variability. Volume measurement tends to be more reproducible compared with area measurements.

  1. Humidifier for fuel cell using high conductivity carbon foam

    Science.gov (United States)

    Klett, James W.; Stinton, David P.

    2006-12-12

    A method and apparatus of supplying humid air to a fuel cell is disclosed. The extremely high thermal conductivity of some graphite foams lends itself to enhance significantly the ability to humidify supply air for a fuel cell. By utilizing a high conductivity pitch-derived graphite foam, thermal conductivity being as high as 187 W/m.dot.K, the heat from the heat source is more efficiently transferred to the water for evaporation, thus the system does not cool significantly due to the evaporation of the water and, consequently, the air reaches a higher humidity ratio.

  2. High-fat diet increases O-GlcNAc levels in cerebral arteries: a link to vascular dysfunction associated with hyperlipidaemia/obesity?

    Science.gov (United States)

    Lima, Victor V; Giachini, Fernanda R; Matsumoto, Takayuki; Li, Weiguo; Bressan, Alecsander F M; Chawla, Dhruv; Webb, R Clinton; Ergul, Adviye; Tostes, Rita C

    2016-06-01

    Obesity and high fat intake induce alterations in vascular function and structure. Aberrant O-GlcNAcylation (O-GlcNAc) of vascular proteins has been implicated in vascular dysfunction associated with cardiovascular and metabolic diseases. In the present study, we tested the hypothesis that high-fat diet (HFD)-mediated increases in O-GlcNAc-modified proteins contribute to cerebrovascular dysfunction. O-GlcNAc-protein content was increased in arteries from male Wistar rats treated with a HFD (45% fat) for 12 weeks compared with arteries from rats on control diet (CD). HFD augmented body weight [(g) 550±10 compared with 502±10 CD], increased plasma triacylglycerols [(mg/dl) 160±20 compared with 95±15 CD] and increased contractile responses of basilar arteries to serotonin [5-hydroxytryptamine (5-HT)] [(pD2) 7.0±0.1 compared with 6.7±0.09 CD] and the thromboxane analogue 9,11-dideoxy-9α,11α-methanoepoxy prostaglandin F2α (U-46619) [(pD2) 7.2±0.1 compared with 6.8±0.09 CD]. Of importance, increased levels of O-GlcNAc [induced by 24 h-incubation of vessels with a potent inhibitor of O-GlcNAcase (OGA), O-(2-acetamido-2-deoxy-D-glucopyranosylidene)amino-N-phenylcarbamate (PugNAc)] increased basilar artery contractions in response to U-46619 [(pD2) 7.4±0.07 compared with 6.8±0.08 CD] and 5-HT [(pD2) 7.5±0.06 compared with 7.1±0.1 CD]. Vessels from rats on the HFD for 12 weeks and vessels treated with PugNAc displayed increased phosphorylation of p38 (Thr(180/182)) and extracellular signal-regulated kinase 1/2 (Erk1/2) (Ser(180/221)). Increased 5HT-induced contractions in arteries from rats on the HFD or in arteries incubated with PugNAc were abrogated by mitogen-activated protein kinase (MAPK) inhibitors. Our data show that HFD augments cerebrovascular O-GlcNAc and this modification contributes to increased contractile responses and to the activation of the MAPK pathway in the rat basilar artery.

  3. High-resolution transmission electron microscopy and energetics of flattened carbon nonoshells

    Energy Technology Data Exchange (ETDEWEB)

    Bourgeois, L.N.; Bursill, L.A

    1998-09-01

    When examined under a high-resolution transmission electron microscope, carbon soot produced alongside buckytubes in an arc-discharge is found to contain a small percentage of flattened carbon shells. These objects are shown to be small graphite flakes which eliminated their dangling bonds by terminating their edges with highly curved junctions. Ideal models for these structures are presented, and their energy estimated. The calculations show that the establishment of highly curved junctions is energetically favourable for a graphite flake in an inert atmosphere. Flattened shells also appear more stable than their `inflated` counterparts (fullerene `onions` and buckytubes) when the shell dimensions obey specific criteria.(authors) 29 refs., 4 figs.

  4. High power density aqueous hybrid supercapacitor combining activated carbon and highly conductive spinel cobalt oxide

    Science.gov (United States)

    Godillot, G.; Taberna, P.-L.; Daffos, B.; Simon, P.; Delmas, C.; Guerlou-Demourgues, L.

    2016-11-01

    The remarkable electrochemical behavior of complete activated carbon/cobalt oxide cells is reported in the present work. Among the various weight ratios between the positive and negative electrodes evaluated, the best features are obtained with an overcapacitive cobalt oxide electrode. The energy densities obtained by this system (20 Wh kg-1 for a power density of 209 W kg-1) are twice higher than those measured for a activated carbon/activated carbon symmetric cell, in the same operating conditions. With discharge capacities around 62 F g-1, this system is among the best ones reported in the literature for this category.

  5. Dilatometric investigations of phase transformations at heating and cooling of hardened, unalloyed, high-carbon steels

    Directory of Open Access Journals (Sweden)

    J. Pacyna

    2011-05-01

    Full Text Available Purpose: The reason for writing this paper was to describe the kinetics of phase transformations during continuous heating from hardened state and subsequent cooling of unalloyed high carbon steel.Design/methodology/approach: Dilatometric investigations were performed using a DT 1000 dilatometer of a French company Adamel. Samples after quenching and quenching and sub-quenching in liquid nitrogen (-196 °C were heated up 700 °C at the rate of 0.05 °C/s and subsequent cooled to room temperature at the rate of 0.05 °C/s.Findings: Regardless of heating the hardened high-carbon steel to 700 °C, a small fraction of the retained austenite remained in its structure, and was changing into fresh martensite only during cooling in the temperature range: 280°C-170°C.Research limitations/implications: Schematic presentation of the differential curve of tempering of the hardened high-carbon, unalloyed steel illustrating the phase transformations occurring during heating from hardened state.Practical implications: An observation, that a small fraction of the retained austenite remained in the structure of tempered high-carbon steel, indicates that even unalloyed steel should be tempered two times.Originality/value: Detailed descriptions of kinetics phase transformations during heating from hardened state of unalloyed high carbon steel.

  6. Contrasting vulnerability of drained tropical and high-latitude peatlands to fluvial loss of stored carbon

    Science.gov (United States)

    Evans, Chris D.; Page, Susan E.; Jones, Tim; Moore, Sam; Gauci, Vincent; Laiho, Raija; Hruška, Jakub; Allott, Tim E. H.; Billett, Michael F.; Tipping, Ed; Freeman, Chris; Garnett, Mark H.

    2014-11-01

    Carbon sequestration and storage in peatlands rely on consistently high water tables. Anthropogenic pressures including drainage, burning, land conversion for agriculture, timber, and biofuel production, cause loss of pressures including drainage, burning, land conversion for agriculture, timber, and biofuel production, cause loss of peat-forming vegetation and exposure of previously anaerobic peat to aerobic decomposition. This can shift peatlands from net CO2 sinks to large CO2 sources, releasing carbon held for millennia. Peatlands also export significant quantities of carbon via fluvial pathways, mainly as dissolved organic carbon (DOC). We analyzed radiocarbon (14C) levels of DOC in drainage water from multiple peatlands in Europe and Southeast Asia, to infer differences in the age of carbon lost from intact and drained systems. In most cases, drainage led to increased release of older carbon from the peat profile but with marked differences related to peat type. Very low DOC-14C levels in runoff from drained tropical peatlands indicate loss of very old (centuries to millennia) stored peat carbon. High-latitude peatlands appear more resilient to drainage; 14C measurements from UK blanket bogs suggest that exported DOC remains young (hydraulic conductivity and temperature, as well as the extent of disturbance associated with drainage, notably land use changes in the tropics. Data from the UK Peak District, an area where air pollution and intensive land management have triggered Sphagnum loss and peat erosion, suggest that additional anthropogenic pressures may trigger fluvial loss of much older (>500 year) carbon in high-latitude systems. Rewetting at least partially offsets drainage effects on DOC age.

  7. Ecological Network Analysis for a Low-Carbon and High-Tech Industrial Park

    Directory of Open Access Journals (Sweden)

    Yi Lu

    2012-01-01

    Full Text Available Industrial sector is one of the indispensable contributors in global warming. Even if the occurrence of ecoindustrial parks (EIPs seems to be a good improvement in saving ecological crises, there is still a lack of definitional clarity and in-depth researches on low-carbon industrial parks. In order to reveal the processes of carbon metabolism in a low-carbon high-tech industrial park, we selected Beijing Development Area (BDA International Business Park in Beijing, China as case study, establishing a seven-compartment- model low-carbon metabolic network based on the methodology of Ecological Network Analysis (ENA. Integrating the Network Utility Analysis (NUA, Network Control Analysis (NCA, and system-wide indicators, we compartmentalized system sectors into ecological structure and analyzed dependence and control degree based on carbon metabolism. The results suggest that indirect flows reveal more mutuality and exploitation relation between system compartments and they are prone to positive sides for the stability of the whole system. The ecological structure develops well as an approximate pyramidal structure, and the carbon metabolism of BDA proves self-mutualistic and sustainable. Construction and waste management were found to be two active sectors impacting carbon metabolism, which was mainly regulated by internal and external environment.

  8. Calculations of Gas-liquid Equilibrium in Wellbore with High Carbon dioxide Flow

    Science.gov (United States)

    Zhang, Jiaming; Wu, Xiaodong; Wang, Bo; Liu, Kai; Gao, Yue

    2014-05-01

    Carbon dioxide injection not only enhances the oil recovery dramatically, but also it will reduce the greenhouse effect, therefore, Carbon dioxide injection technique is applied extensively. During the process of carbon dioxide displacement, when carbon dioxide breaks though into oil production wells, carbon dioxide content will impacts the phase state and physical properties of the mixed liquor in the wellbore, as a result, it will affect the calculation of temperature and pressure in oil production wells. Applying the conventional black-oil model to calculate the phase state of the miscible fluids is unacceptable. To tackle the problem, this paper uses the gas-liquid flash theory and component model to program software, so that the phase state (gas, liquid or gas-liquid) and physical properties of the mixed liquor (including hydrogen sulfide, carbon dioxide and hydrocarbon) under initial conditions is calculated, moreover, the impact of carbon dioxide content on the physical properties(mainly including density, viscosity, specific heat at const pressure, surface tension, etc) of mixed liquor in oil production wells is analyzed in this paper. The comparison of the results shows that this model can meet the engineering needs with high accuracy.

  9. Enabling linear alkyl carbonate electrolytes for high voltage Li-ion cells

    Science.gov (United States)

    Xia, Jian; Petibon, Remi; Xiong, Deijun; Ma, Lin; Dahn, J. R.

    2016-10-01

    Some of the problems of current electrolytes for high voltage Li-ion cells originate from ethylene carbonate (EC) which is thought to be an essential electrolyte component for Li-ion cells. Ethylene carbonate-free electrolytes containing 1 M LiPF6 in ethylmethyl carbonate (EMC) with small loadings of vinylene carbonate, fluoroethylene carbonate, or (4R,5S)-4,5-Difluoro-1,3-dioxolan-2-one acting as ;enablers; were developed. These electrolytes used in Li(Ni0.4Mn0.4Co0.2)O2/graphite pouch type Li-ion cells tested at 4.2 V and 4.5 V yielded excellent charge-discharge cycling and storage properties. The results for cells containing linear alkyl carbonate electrolytes with no EC were compared to those of cells with EC-containing electrolytes incorporating additives proven to enhance cyclability of cells. The combination of EMC with appropriate amounts of these enablers yields cells with better performance than cells with EC-containing electrolytes incorporating additives tested to 4.5 V. Further optimizing these linear alkyl carbonate electrolytes with appropriate co-additives may represent a viable path to the successful commercial utilization of NMC/graphite Li-ion cells operated to 4.5 V and above.

  10. Ecological network analysis for a low-carbon and high-tech industrial park.

    Science.gov (United States)

    Lu, Yi; Su, Meirong; Liu, Gengyuan; Chen, Bin; Zhou, Shiyi; Jiang, Meiming

    2012-01-01

    Industrial sector is one of the indispensable contributors in global warming. Even if the occurrence of ecoindustrial parks (EIPs) seems to be a good improvement in saving ecological crises, there is still a lack of definitional clarity and in-depth researches on low-carbon industrial parks. In order to reveal the processes of carbon metabolism in a low-carbon high-tech industrial park, we selected Beijing Development Area (BDA) International Business Park in Beijing, China as case study, establishing a seven-compartment- model low-carbon metabolic network based on the methodology of Ecological Network Analysis (ENA). Integrating the Network Utility Analysis (NUA), Network Control Analysis (NCA), and system-wide indicators, we compartmentalized system sectors into ecological structure and analyzed dependence and control degree based on carbon metabolism. The results suggest that indirect flows reveal more mutuality and exploitation relation between system compartments and they are prone to positive sides for the stability of the whole system. The ecological structure develops well as an approximate pyramidal structure, and the carbon metabolism of BDA proves self-mutualistic and sustainable. Construction and waste management were found to be two active sectors impacting carbon metabolism, which was mainly regulated by internal and external environment.

  11. Black Carbon in Estuarine (Coastal) High-molecular-weight Dissolved Organic Matter

    Science.gov (United States)

    Mannino, Antonio; Harvey, H. Rodger

    2003-01-01

    Dissolved organic matter (DOM) in the ocean constitutes one of the largest pools of organic carbon in the biosphere, yet much of its composition is uncharacterized. Observations of black carbon (BC) particles (by-products of fossil fuel combustion and biomass burning) in the atmosphere, ice, rivers, soils and marine sediments suggest that this material is ubiquitous, yet the contribution of BC to the ocean s DOM pool remains unknown. Analysis of high-molecular-weight DOM isolated from surface waters of two estuaries in the northwest Atlantic Ocean finds that BC is a significant component of DOM, suggesting that river-estuary systems are important exporters of BC to the ocean through DOM. We show that BC comprises 4-7% of the dissolved organic carbon (DOC) at coastal ocean sites, which supports the hypothesis that the DOC pool is the intermediate reservoir in which BC ages prior to sedimentary deposition. Flux calculations suggest that BC could be as important as vascular plant-derived lignin in terms of carbon inputs to the ocean. Production of BC sequesters fossil fuel- and biomass-derived carbon into a refractory carbon pool. Hence, BC may represent a significant sink for carbon to the ocean.

  12. Synthesis of LiFePO_4/C Composite Cathode Materials Using High Surface Area Carbon as Carbon Sources

    Institute of Scientific and Technical Information of China (English)

    George; Ting-kuo; Fey; Kai-Lun; Chiang

    2007-01-01

    1 Results The pyrolyzed product of peanut shells was utilized as a carbon source to synthesize a LiFePO4/C composite.The advantages of using agricultural wastes such as peanut shells are low costs,easy processing,and environmentally benigness.Peanut shell was first treated with a porogenic agent to produce a precursor with high porosity and surface area (>2 000 m2·g-1).A small amount of precursor was mixed with LiFePO4 fine powders and heated.The optimum calcination process for synthesizing LiFePO4/C co...

  13. Effects of a carbon convection field on large diamond growth under high-pressure high-temperature conditions

    Institute of Scientific and Technical Information of China (English)

    Hu Mei-Hua; Li Shang-Sheng; Ma Hong-An; Su Tai-Chao; Li Xiao-Lei; Hu Qiang; Jia Xiao-Peng

    2012-01-01

    Large diamond crystals were successfully synthesized by a FeNi-C system using the temperature gradient method under high-pressure high-temperature conditions.The assembly of the growth cell was improved and the growth process of diamond was investigated.Effects of the symmetry of the carbon convection field around the growing diamond crystal were investigated systematically by adjusting the position of the seed crystal in the melted catalyst/solvent.The results indicate that the morphologies and metal inclusion distributions of the synthetic diamond crystals vary obviously in both symmetric and non-symmetric carbon convection fields with temperature.Moreover,the finite element method was applied to analyze the carbon convection mode of the melted catalyst/solvent around the diamond crystal.This work is helpful for understanding the growth mechanism of diamond.

  14. INFLUENCE OF BAINITE STRUCTURE ON MECHANICAL CHARACTERISTICS OF HIGH-CARBON WIRE

    Directory of Open Access Journals (Sweden)

    A. Ju. Borisenko

    2009-01-01

    Full Text Available Influence of structure of beynit is explored on mechanical properties after thermal treatment of wire from the steel 80. The structural state of beynit, providing the high complex of mechanical properties of high-carbon wire, is definite.

  15. Vulnerability of high-latitude soil organic carbon in North America to disturbance

    Science.gov (United States)

    Guido Grosse; Jennifer Harden; Merritt Turetsky; A. David McGuire; Philip Camill; Charles Tarnocai; Steve Frolking; Edward Schuur; Torre Jorgenson; Sergei Marchenko; Vladimir Romanovsky; Kimberly P. Wickland; Nancy French; Mark Waldrop; Laura Bourgeau-Chavez; Robert G. Streigl

    2011-01-01

    This synthesis addresses the vulnerability of the North American high-latitude soil organic carbon (SOC) pool to climate change. Disturbances caused by climate warming in arctic, subarctic, and boreal environments can result in significant redistribution of C among major reservoirs with potential global impacts. We divide the current northern high-latitude SOC pools...

  16. High Performance Ambipolar Field-Effect Transistor of Random Network Carbon Nanotubes

    NARCIS (Netherlands)

    Bisri, Satria Zulkarnaen; Gao, Jia; Derenskyi, Vladimir; Gomulya, Widianta; Iezhokin, Igor; Gordiichuk, Pavlo; Herrmann, Andreas; Loi, Maria Antonietta

    2012-01-01

    Ambipolar field-effect transistors of random network carbon nanotubes are fabricated from an enriched dispersion utilizing a conjugated polymer as the selective purifying medium. The devices exhibit high mobility values for both holes and electrons (3 cm(2)/V.s) with a high on/off ratio (10(6)). The

  17. Corrosion of Candidate High Temperature Alloys in Supercritical Carbon Dioxide

    Science.gov (United States)

    Parks, Curtis J.

    The corrosion resistance of three candidate alloys is tested in supercritical carbon dioxide (S-CO2) at different levels of temperature and pressure for up to 3000 hours. The purpose of the testing is to evaluate the compatibility of different engineering alloys in S-CO2 for use in a S-CO 2 Brayton cycle. The three alloys used are austenitic stainless steel 316, iron-nickel-base superalloy 718, and nickel-base superalloy 738. Each alloy is exposed to four combinations of temperature and pressure, consisting of either 550°C or 700°C at either 15 or 25 MPa for up to 1500 hours. At each temperature, an additional sample set is tested for 3000 hours and experienced an increase in pressure from 15 MPa to 25 MPa after 1500 hours of testing. All three alloys are successful in producing a protective oxide layer at the lower temperature of 550°C based on the logarithmic weight gain trends. At the higher temperature of 700°C, 316SS exhibits unfavourable linear weight gain trends at both pressures of 15 and 25 MPa. In comparison, IN-718 and IN-738 performs similarly in producing a protective oxide layer illustrated through a power weight gain relation. The effect of pressure is most pronounced at the operating temperature of 700°C, where the higher pressure of 25 MPa results in an increased rate of oxide formation. SEM analysis exposes a thin film oxide for both IN-718 and IN-738 but severe intergranular corrosion is exhibited by IN-738. Based on the testing conducted, both alloys show favourable characteristics for use in S-CO 2 conditions up to 700°C, but further testing is required to characterize the effect of the intergranular corrosion on the stability of oxide in IN-738. 316SS provided favourable results for use in temperatures of 550°C, but the protective oxide deteriorated at an operating temperature of 700°C.

  18. Hierarchical porous carbon aerogel derived from bagasse for high performance supercapacitor electrode

    Science.gov (United States)

    Hao, Pin; Zhao, Zhenhuan; Tian, Jian; Li, Haidong; Sang, Yuanhua; Yu, Guangwei; Cai, Huaqiang; Liu, Hong; Wong, C. P.; Umar, Ahmad

    2014-09-01

    Renewable, cost-effective and eco-friendly electrode materials have attracted much attention in the energy conversion and storage fields. Bagasse, the waste product from sugarcane that mainly contains cellulose derivatives, can be a promising candidate to manufacture supercapacitor electrode materials. This study demonstrates the fabrication and characterization of highly porous carbon aerogels by using bagasse as a raw material. Macro and mesoporous carbon was first prepared by carbonizing the freeze-dried bagasse aerogel; consequently, microporous structure was created on the walls of the mesoporous carbon by chemical activation. Interestingly, it was observed that the specific surface area, the pore size and distribution of the hierarchical porous carbon were affected by the activation temperature. In order to evaluate the ability of the hierarchical porous carbon towards the supercapacitor electrode performance, solid state symmetric supercapacitors were assembled, and a comparable high specific capacitance of 142.1 F g-1 at a discharge current density of 0.5 A g-1 was demonstrated. The fabricated solid state supercapacitor displayed excellent capacitance retention of 93.9% over 5000 cycles. The high energy storage ability of the hierarchical porous carbon was attributed to the specially designed pore structures, i.e., co-existence of the micropores and mesopores. This research has demonstrated that utilization of sustainable biopolymers as the raw materials for high performance supercapacitor electrode materials is an effective way to fabricate low-cost energy storage devices.Renewable, cost-effective and eco-friendly electrode materials have attracted much attention in the energy conversion and storage fields. Bagasse, the waste product from sugarcane that mainly contains cellulose derivatives, can be a promising candidate to manufacture supercapacitor electrode materials. This study demonstrates the fabrication and characterization of highly porous carbon

  19. High Temperature Spectrum for v3 Band of Carbon Dioxide

    Institute of Scientific and Technical Information of China (English)

    SONG Xiao-Shu; YANG Xiang-Dong; UO Yun-Dong; WANG Jun; CHENG Xin-Lu; LING-HU Rong Feng

    2007-01-01

    The total internal partition sums (TIPS) are calculated at the temperature up to 6000 K for 12C16O2. Using the calculated partition functions, we produce the line intensities of v3 band of 12C16O2 at several high temperatures.The results show that the calculated line intensities are in very good agreement with those of HITRAN database at the temperature up to 3000 K, which provides a strong support for the calculations of TIPS and line intensities at high temperature. Then the calculation is extended to further high temperature, and the simulated spectra of v3 band of 12C16O2 at 5000 and 6000 K are reported.

  20. High temperature electrolysis of steam and carbon dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Hoejgaard Jensen, Soeren [H.C. Oersted Institute, Copenhagen (Denmark); Hoegh, Jens V.T.; Barfod, Rasmus; Mogensen, Mogens [Risoe National Lab., Materials Research Dept., Roskilde (Denmark)

    2003-09-01

    The vision behind this work is establishment of methods for cheap production of hydrogen, H{sub 2}, and methane, CH{sub 4}, by electrolysis. CH{sub 4} is a particular suitable storage medium for renewable energy. Preliminary electrolysis experiments with a second generation of solid oxide fuel cells developed at Risoe National Laboratory, Denmark, show that these cells also have a high potential as solid oxide electrolyse cells. Furthermore, the experiments indicate that production of CH{sub 4} by high temperature electrolysis of mixtures of H{sub 2} and CO{sub 2} is possible using these cells, but very high gas pressure seems necessary to obtain acceptable yields. The results also indicate that much more research and development work is needed in order to make a sufficient durable electrolyse cell. (au)

  1. High-Dose versus Low-Dose Vitamin D Supplementation and Arterial Stiffness among Individuals with Prehypertension and Vitamin D Deficiency

    Directory of Open Access Journals (Sweden)

    Amanda Zaleski

    2015-01-01

    Full Text Available Introduction. Vitamin D deficiency is associated with the onset and progression of hypertension and cardiovascular disease (CVD. However, mechanisms underlying vitamin D deficiency-mediated increased risk of CVD remain unknown. We sought to examine the differential effect of high-dose versus low-dose vitamin D supplementation on markers of arterial stiffness among ~40 vitamin D deficient adults with prehypertension. Methods. Participants were randomized to high-dose (4000 IU/d versus low-dose (400 IU/d oral vitamin D3 for 6 months. 24 hr ambulatory blood pressure (BP, carotid-femoral pulse wave velocity, and pulse wave analyses were obtained at baseline and after 6 months of vitamin D supplementation. Results. There were no changes in resting BP or pulse wave velocity over 6 mo regardless of vitamin D dose (all p>0.202. High-dose vitamin D decreased augmentation index and pressure by 12.3 ± 5.3% (p=0.047 and 4.0 ± 1.5 mmHg (p=0.02, respectively. However, these decreases in arterial stiffness were not associated with increases in serum 25-hydroxyvitamin D over 6 mo (p=0.425. Conclusion. High-dose vitamin D supplementation appears to lower surrogate measures of arterial stiffness but not indices of central pulse wave velocity. Clinical Trial Registration. This trial is registered with www.clinicaltrials.gov (Unique Identifier: NCT01240512.

  2. Can bioenergy cropping compensate high carbon emissions from large-scale deforestation of mid to high latitudes?

    Directory of Open Access Journals (Sweden)

    P. Dass

    2013-02-01

    Full Text Available Numerous studies have concluded that deforestation of mid to high latitudes result in a global cooling. This is mainly because of the increased albedo of deforested land which dominates over other biogeophysical and biogeochemical mechanisms in the energy balance. This dominance however may be due to an underestimation of the biogeochemical response, as carbon emissions are typically at or below the lower end of estimates. Here, we use the dynamic global vegetation model LPJmL for a better estimate of the carbon cycle under such large-scale deforestation. These studies are purely academic to understand the role of vegetation in the energy balance and the earth system. They must not be mistaken as possible mitigation options, because of the devastating effects on pristine ecosystems. We show that even optimistic assumptions on the manageability of these areas and its utilization for bioenergy crops could not make up for the strong carbon losses in connection with the losses of vegetation carbon and the long-term decline of soil carbon stocks. We find that the global biophysical bioenergy potential is 78.9 ± 7.9 EJ yr−1 of primary energy at the end of the 21st century for the most plausible scenario. Due to avoided usage of fossil fuels over the time frame of this experiment, the cooling due to the biogeophysical feedback could be supplemented by an avoided warming of approximately 0.1 to 0.3 °C. However, the extensive deforestation simulated in this study causes an immediate emission of 182.3 ± 0.7 GtC followed by long term emissions. In the most plausible scenario, this carbon debt is not neutralized even if bioenergy production is assumed to be carbon-neutral other than for the land use emissions so that global temperatures would increase by ~0.2 to 0.6 °C by the end of the 21st century. The carbon dynamics in the high latitudes, especially with respect to permafrost dynamics and long-term carbon losses, require additional attention in

  3. Optimization of the sintering atmosphere for high-density hydroxyapatite-carbon nanotube composites.

    Science.gov (United States)

    White, Ashley A; Kinloch, Ian A; Windle, Alan H; Best, Serena M

    2010-10-06

    Hydroxyapatite-carbon nanotube (HA-CNT) composites have the potential for improved mechanical properties over HA for use in bone graft applications. Finding an appropriate sintering atmosphere for this composite presents a dilemma, as HA requires water in the sintering atmosphere to remain phase pure and well hydroxylated, yet CNTs oxidize at the high temperatures required for sintering. The purpose of this study was to optimize the atmosphere for sintering these composites. While the reaction between carbon and water to form carbon monoxide and hydrogen at high temperatures (known as the 'water-gas reaction') would seem to present a problem for sintering these composites, Le Chatelier's principle suggests this reaction can be suppressed by increasing the concentration of carbon monoxide and hydrogen relative to the concentration of carbon and water, so as to retain the CNTs and keep the HA's structure intact. Eight sintering atmospheres were investigated, including standard atmospheres (such as air and wet Ar), as well as atmospheres based on the water-gas reaction. It was found that sintering in an atmosphere of carbon monoxide and hydrogen, with a small amount of water added, resulted in an optimal combination of phase purity, hydroxylation, CNT retention and density.

  4. High-performance Sn@carbon nanocomposite anode for lithium batteries

    Science.gov (United States)

    Meschini, Ida; Nobili, Francesco; Mancini, Marilena; Marassi, Roberto; Tossici, Roberto; Savoini, Alberto; Focarete, Maria Letizia; Croce, Fausto

    2013-03-01

    Nanosize tin particles (Sn-PMCMT) embedded in electrically conducting porous multichannel carbon microtubes are synthesized by co-electrospinning followed by air stabilization and carbonization in Ar/H2 atmosphere. Scanning and transmission electron microscopy show that the material is nanostructured with nanosize Sn particles well embedded into the carbon host matrix. Composite electrodes prepared using Sn-PMCMT, Super-P carbon and Na-carboxymethylcellulose as binder, exhibit a superior rate capability and exceptional cycle life in cell tests at room temperature. Discharge capacities as high as 632 mAh g-1 at 0.7 C rate are obtained during the first galvanostatic cycles. The delivered capacities are still in excess of 350 mAh g-1 after 600 cycles, most of them performed at 2 C rate. These outstanding results represent the highest performance so far reported for this type of electrode.

  5. Climatic consequences of very high carbon dioxide levels in the earth's early atmosphere

    Science.gov (United States)

    Kasting, James F.; Ackerman, Thomas P.

    1986-01-01

    The possible consequences of very high carbon dioxide concentrations in the earth's early atmosphere have been investigated with a radiative-convective climate model. The early atmosphere would apparently have been stable against the onset of a runaway greenhouse (that is, the complete evaporation of the oceans) for carbon dioxide pressures up to at least 100 bars. A 10- to 20-bar carbon dioxide atmosphere, such as may have existed during the first several hundred million years of the earth's history, would have had a surface temperature of approximately 85 to 110 C. The early stratosphere should have been dry, thereby precluding the possibility of an oxygenic prebiotic atmosphere caused by photodissociation of water vapor followed by escape of hydrogen to space. Earth's present atmosphere also appears to be stable against a carbon dioxide-induced runaway greenhouse.

  6. Adsorption of polar probe molecules on plasma-oxidised high-strength carbon fibres

    Energy Technology Data Exchange (ETDEWEB)

    Montes-Moran, M.A.; Martinez-Alonso, A.; Tascon, J.M.D. [Instituto Nacional del Carbon, CSIC, Apartado 73, 33080, Oviedo (Spain)

    2002-06-20

    The objective of this work was to examine the effect of oxygen plasma treatment on the surface chemistry of carbon fibres. Virgin, unsized high-strength carbon fibres were subjected to oxygen plasma treatments with different degrees of severity. Adsorption of probe molecules with different acid-base characteristics (acetone, carbon tetrachloride, trichloromethane, dichloromethane, diethyl ether, nitromethane, tetrahydrofurane) was measured at 303-353 K using inverse gas chromatography (IGC) at infinite dilution. Plasma treatment brings about increases in the specific free energy of adsorption of either acidic, basic or amphoteric probe molecules, indicating creation of surface functionalities with various acid-base strengths. This helps to justify the improvement in interfacial adhesion in polycarbonate matrix composites following plasma treatment of carbon fibres.

  7. Fabrication of graphene coated carbon fiber microelectrode for highly sensitive detection application.

    Science.gov (United States)

    Bai, Jie; Wang, Xiaojuan; Meng, Yuning; Zhang, Hui-Min; Qu, Liangti

    2014-01-01

    Graphene, as a novel carbon nanomaterial, exhibits superior performance in electrochemical sensors. Here, graphene was applied to the microelectrode system by a simple method. A novel graphene coating carbon fiber microelectrode (G-CFM) was fabricated by electrodepositing graphene on the surface of carbon fiber. The fabrication method is fast and simple. Scanning electron microscopy and Raman spectroscopy demonstrated that carbon fiber was successfully modified by graphene. The electrochemical behavior of G-CFM was characterized by potassium ferricyanide and dopamine (DA). The electrode exhibited much larger current response and less overpotential response, compared to CFM. The microsensor for DA showed good sensitivity and selectivity, and the electrode had good stability. It is believable that the unique characteristic of graphene holds promise for the advanced microelectrode system for highly sensitive detection of various targets.

  8. Climatic consequences of very high carbon dioxide levels in the earth's early atmosphere

    Science.gov (United States)

    Kasting, James F.; Ackerman, Thomas P.

    1986-01-01

    The possible consequences of very high carbon dioxide concentrations in the earth's early atmosphere have been investigated with a radiative-convective climate model. The early atmosphere would apparently have been stable against the onset of a runaway greenhouse (that is, the complete evaporation of the oceans) for carbon dioxide pressures up to at least 100 bars. A 10- to 20-bar carbon dioxide atmosphere, such as may have existed during the first several hundred million years of the earth's history, would have had a surface temperature of approximately 85 to 110 C. The early stratosphere should have been dry, thereby precluding the possibility of an oxygenic prebiotic atmosphere caused by photodissociation of water vapor followed by escape of hydrogen to space. Earth's present atmosphere also appears to be stable against a carbon dioxide-induced runaway greenhouse.

  9. A secular carbon debt from atmospheric high temperature combustion of stem wood?

    DEFF Research Database (Denmark)

    Czeskleba-Dupont, Rolf

    2012-01-01

    ' approach for smokestack emissions that was propagated within the Kyoto process, the first phase of which is terminating in 2012. Otherwise, it is tolerated that the substitution of wood pellets for coal or other fossil fuels creates long lasting extra emissions of carbon dioxide – a mistake of climate......Basically, combustion of woody biomass in high temperature processes that react with atmospheric air results in a long lasting addition of carbon dioxide to the atmosphere. When harvesting large extra amounts of stem tree for energetic use, a global as well as secular time frame is needed to assess...... overall consequences with due attention given to biosphere processes, including the complex productivity of whole ecosystems. Analytically, a time dependent variable of carbon neutralization can be traced by a simple carbon neutrality or CN factor. Using the forgotten Marland approach, project managers...

  10. Carbon coatings for extreme-ultraviolet high-order laser harmonics

    Energy Technology Data Exchange (ETDEWEB)

    Coraggia, S.; Frassetto, F. [CNR-Institute of Photonics and Nanotechnologies, Laboratory for UV and X-Ray Optical Research, via Trasea 7, 35131 Padova (Italy); Aznarez, J.A.; Larruquert, J.I.; Mendez, J.A. [GOLD-Instituto de Optica-Consejo Superior de Investigaciones Cientificas, Serrano 144, 28006 Madrid (Spain); Negro, M.; Stagira, S.; Vozzi, C. [Department of Physics-Politecnico of Milano and CNR-Institute of Photonics and Nanotechnologies, Piazza Leonardo Da Vinci 32, 20133 Milano (Italy); Poletto, L., E-mail: poletto@dei.unipd.i [CNR-Institute of Photonics and Nanotechnologies, Laboratory for UV and X-Ray Optical Research, via Trasea 7, 35131 Padova (Italy)

    2011-04-11

    The experimental study of the optical properties of thin carbon films to be used as grazing-incidence coatings for extreme-ultraviolet high-order harmonics is presented. The carbon sa