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Sample records for high arterial carbon

  1. Highly stretchable carbon aerogels.

    Science.gov (United States)

    Guo, Fan; Jiang, Yanqiu; Xu, Zhen; Xiao, Youhua; Fang, Bo; Liu, Yingjun; Gao, Weiwei; Zhao, Pei; Wang, Hongtao; Gao, Chao

    2018-02-28

    Carbon aerogels demonstrate wide applications for their ultralow density, rich porosity, and multifunctionalities. Their compressive elasticity has been achieved by different carbons. However, reversibly high stretchability of neat carbon aerogels is still a great challenge owing to their extremely dilute brittle interconnections and poorly ductile cells. Here we report highly stretchable neat carbon aerogels with a retractable 200% elongation through hierarchical synergistic assembly. The hierarchical buckled structures and synergistic reinforcement between graphene and carbon nanotubes enable a temperature-invariable, recoverable stretching elasticity with small energy dissipation (~0.1, 100% strain) and high fatigue resistance more than 10 6 cycles. The ultralight carbon aerogels with both stretchability and compressibility were designed as strain sensors for logic identification of sophisticated shape conversions. Our methodology paves the way to highly stretchable carbon and neat inorganic materials with extensive applications in aerospace, smart robots, and wearable devices.

  2. Congenital heart disease with high origin of coronary artery

    International Nuclear Information System (INIS)

    Zhu Ming; Li Yuhua; Zhong Yumin

    2002-01-01

    Objective: To report 6 cases of congenital heart disease with high origin of coronary artery and to evaluate the imaging method for diagnosis of congenital high origin of coronary artery. Methods: Six patients with congenital high origin of coronary artery underwent angiocardiography, echocardiography, and 2 patients also underwent magnetic resonance examination. All 6 cases were confirmed by operation. Results: All 6 cases were congenital high origin of right coronary artery. Angiocardiography made correct diagnosis in all 6 cases; MRI made the correct diagnosis in 1 of the 2 cases; echocardiography made 1 correct diagnosis. Conclusion: Correct diagnosis of congenital high origin of coronary artery was very important for patients with congenital heart disease. Angiocardiography was a very reliable imaging method and MRI can play an important role in preoperative diagnosis of congenital high origin of coronary artery

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

    International Nuclear Information System (INIS)

    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; Abe, Takashi; Harada, Masafumi; Yamamoto, Nobuaki; Kaji, Ryuji

    2017-01-01

    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.)

  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. 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 autoreg...

  6. Automatic control of arterial carbon dioxide tension in mechanically ventilated patients.

    Science.gov (United States)

    Fernando, Tyrone; Cade, John; Packer, John

    2002-12-01

    This paper presents a method of controlling the arterial carbon dioxide tension of patients receiving mechanical ventilation. Controlling of the CO2 tension is achieved by regulating the ventilator initiated breath frequency and also volume per breath.

  7. Case Report: High origin of the right testicular artery coursing ...

    African Journals Online (AJOL)

    During routine dissection we observed a high origin of the right testicular artery from the abdominal aorta in a middle-aged formalin-fixed male cadaver of indigenous Kenyan descent. The artery arched above the right renal vein to course through a hiatus in the inferior vena cava at its confluence with the right renal vein.

  8. HIGH ORIGIN OF SUPERFICIAL ULNAR ARTERY- A CASE REPORT

    Directory of Open Access Journals (Sweden)

    Anjana Jayakumaran Nair

    2017-03-01

    Full Text Available BACKGROUND High origin and superficially placed ulnar artery is a rare anatomical variant that usually arises either in the axilla or arm and runs a superficial course in the forearm, enters the hand and participates in the formation of superficial palmar arch. During routine dissection of cadavers in our department, we observed a unilateral case of high origin and superficial ulnar artery in a human male cadaver. It originated from the brachial artery in the lower third of arm 4 cm above its bifurcation. From its origin, it passed downwards along the medial aspect of forearm, superficial to the flexors, entered hand superficial to the flexor retinaculum and formed superficial palmar arch. The knowledge of existence of a superficial ulnar artery is important during vascular and reconstructive surgery and also in evaluation of angiographic images. Superficial position makes it more vulnerable to trauma and more accessible to cannulation.

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

    OpenAIRE

    Michael Kelly; Marcus Bradley; Ankur Srivastava

    2008-01-01

    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...

  10. High success rate after arterial renal embolisation

    DEFF Research Database (Denmark)

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

    2015-01-01

    . RESULTS: In total, 35 patients were included; their mean age was 64 years (range: 17-95 years): eight females and 27 males. A total of 15 patients underwent embolisation due to renal cancer; nine elective and six acute procedures. Seven traumas were embolised. Five AML patients underwent embolisation......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...

  11. 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....

  12. Rare high origin of the radial artery: a bilateral, symmetrical case ...

    African Journals Online (AJOL)

    Arterial variations in the upper limb can occur at the level of the axillary, brachial, radial and ulnar arteries as well as the palmar arches. This is a report of bilateral, symmetrical high origin of the radial artery from the axillary artery. Knowledge of such variations is important in vascular and reconstructive surgery. (Nig J Surg ...

  13. 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.

  14. Cerebral blood flow response to changes in arterial carbon dioxide tension during hypothermic cardiopulmonary bypass in children

    International Nuclear Information System (INIS)

    Kern, F.H.; Ungerleider, R.M.; Quill, T.J.; Baldwin, B.; White, W.D.; Reves, J.G.; Greeley, W.J.

    1991-01-01

    We examined the relationship of changes in partial pressure of carbon dioxide on cerebral blood flow responsiveness in 20 pediatric patients undergoing hypothermic cardiopulmonary bypass. Cerebral blood flow was measured during steady-state hypothermic cardiopulmonary bypass with the use of xenon 133 clearance methodology at two different arterial carbon dioxide tensions. During these measurements there was no significant change in mean arterial pressure, nasopharyngeal temperature, pump flow rate, or hematocrit value. Cerebral blood flow was found to be significantly greater at higher arterial carbon dioxide tensions (p less than 0.01), so that for every millimeter of mercury rise in arterial carbon dioxide tension there was a 1.2 ml.100 gm-1.min-1 increase in cerebral blood flow. Two factors, deep hypothermia (18 degrees to 22 degrees C) and reduced age (less than 1 year), diminished the effect carbon dioxide had on cerebral blood flow responsiveness but did not eliminate it. We conclude that cerebral blood flow remains responsive to changes in arterial carbon dioxide tension during hypothermic cardiopulmonary bypass in infants and children; that is, increasing arterial carbon dioxide tension will independently increase cerebral blood flow

  15. Carbon dioxide hepatic arterial DSA and CT angiography in swine model

    International Nuclear Information System (INIS)

    Tan Huaqiao; Hu Hongjie; Huang Wenxin; Zhang Shizheng; Dong Yonghua; Zhou Dachun

    2005-01-01

    Objective: To evaluate the imaging findings of carbon dioxide hepatic arterial DSA and CT angiography in normal swine. Methods: In general anaesthesia, hepatic arterial DSA was performed with 10 ml iodinated contrast medium (5 ml/s, 10 ml) in 5 normal swine, and then repeated hepatic arterial CO 2 -DSA was performed with a total of 30-50 ml CO 2 injected by manually operated syringe at the velocity of 5-8 ml/s, followed by CO 2 -CT angiography. All the swine were sacrificed after the procedure, the selective hepatic segments were removed, and pathological examination was carried out. The radiological features of hepatic arterial DSA with iodinated contrast medium and CO 2 and CT angiography with CO 2 were analyzed. The ability of showing the arterio-venous shunt was compared. Results: Hepatic arterio-portal shunt was found in the advanced arterial phase of CO 2 -DSA in three of five swine, which was furthermore demonstrated by CO 2 -CT angiography, but iodinated contrast medium DSA showed no arterio-portal shunt in all swine. The gaseous CO 2 in portal vein was absorbed within 1-3 minutes. No CO 2 shunted into the hepatic vein during CO 2 -DSA and CO 2 -CTA. Histology didn't reveal any abnormal changes caused by CO 2 shunt in the swine liver. Conclusion: (1) Hepatic arterial CO 2 -DSA and CO 2 -CTA can reveal arterio-portal shunt that isn't seen with iodinated contrast medium, the gaseous CO 2 in portal vein was absorbed within 1-3 minutes. (2) The gaseous CO 2 can't shunt into hepatic vein when the hepatic artery is perfused with CO 2 in normal swine. (authors)

  16. A unique case of bifid left testicular artery having its anomalous high origin from renal artery

    OpenAIRE

    Ashwini P Aithal; Naveen Kumar; Swamy S Ravindra; Jyothsna Patil

    2016-01-01

    The testicular arteries are known to originate from the ventrolateral aspect of the abdominal aorta and descend obliquely to the pelvic cavity and supply the testis. An anatomical description of an uncommon variation of the left testicular artery is presented in this case report, highlighting its clinical implications. During routine dissection of a male cadaver, we found that the left testicular artery was bifid and it was arising from the left renal artery. After its origin, it then coursed...

  17. High-Melt Carbon-Carbon Coating for Nozzle Extensions

    Science.gov (United States)

    Thompson, James

    2015-01-01

    Carbon-Carbon Advanced Technologies, Inc. (C-CAT), has developed a high-melt coating for use in nozzle extensions in next-generation spacecraft. The coating is composed primarily of carbon-carbon, a carbon-fiber and carbon-matrix composite material that has gained a spaceworthy reputation due to its ability to withstand ultrahigh temperatures. C-CAT's high-melt coating embeds hafnium carbide (HfC) and zirconium diboride (ZrB2) within the outer layers of a carbon-carbon structure. The coating demonstrated enhanced high-temperature durability and suffered no erosion during a test in NASA's Arc Jet Complex. (Test parameters: stagnation heat flux=198 BTD/sq ft-sec; pressure=.265 atm; temperature=3,100 F; four cycles totaling 28 minutes) In Phase I of the project, C-CAT successfully demonstrated large-scale manufacturability with a 40-inch cylinder representing the end of a nozzle extension and a 16-inch flanged cylinder representing the attach flange of a nozzle extension. These demonstrators were manufactured without spalling or delaminations. In Phase II, C-CAT worked with engine designers to develop a nozzle extension stub skirt interfaced with an Aerojet Rocketdyne RL10 engine. All objectives for Phase II were successfully met. Additional nonengine applications for the coating include thermal protection systems (TPS) for next-generation spacecraft and hypersonic aircraft.

  18. 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.

  19. 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.

  20. Intra-arterial digital subtraction angiography (IA-DSA) with carbon dioxide

    International Nuclear Information System (INIS)

    Takeda, Toshiaki; Ido, Kunio; Yuasa, Yuji

    1988-01-01

    Intra-Arterial Digital Subtraction Angiography (IA-DSA) with Carbon Dioxide (CO 2 ) was performed on 41 patients mainly with liver or renal diseases, and its angiographic manifestation was compared with that of conventional angiography. Although the image quality of the arterial or capillary phase was inferior to that of conventional angiography with iodinated contrast media, the detectablity of arterio-venous shunting was excellent. In fact, DSA with CO 2 revealed the presence of A-V (A-P) shunt in 26 patients (26/41:63.4 % HCC, 13/15:86.7% metastatic liver tumor, 2/3:66.7 % RCC, 1/5:20 %). On the other hand, conventional angiography was able to show in only 5 cases. DSA with CO 2 will become an effective method for detecting minute arterio-venous shunting which can not be demonstrated with conventional angiography. (author)

  1. Carbon black nanoparticles and vascular dysfunction in cultured endothelial cells and artery segments

    DEFF Research Database (Denmark)

    Vesterdal, Lise K; Mikkelsen, Lone; Folkmann, Janne K

    2012-01-01

    Exposure to small size particulates is regarded as a risk factor for cardiovascular disease. We investigated effects of exposure to nanosized carbon black (CB) in human umbilical vein endothelial cells (HUVECs) and segments of arteries from rodents. The CB exposure was associated with increased......, whereas it did not alter the mitochondrial enzyme activity (WST-1) or the nitric oxide level in HUVECs. Incubation of aorta segments with 10µg/ml of CB increased the endothelial-dependent vasorelaxation, induced by acetylcholine, and shifted the endothelium-independent vasorelaxation, induced by sodium...... nitroprusside, towards a decreased sensitivity. In mesenteric arteries, the exposure to 10µg/ml was associated with a reduced pressure-diameter relationship. Incubation with 100µg/ml CB significantly decreased both acetylcholine and sodium nitroprusside responses as well as decreased the receptor...

  2. [Correlation between end-tidal carbon dioxide and partial pressure of arterial carbon dioxide in ventilated newborns].

    Science.gov (United States)

    Feng, Jin-Xing; Liu, Xiao-Hong; Huang, Hui-Jun; Yu, Zhen-Zhu; Yang, Hui; He, Liu-Fang

    2014-05-01

    To study the correlation between end-tidal carbon dioxide (PetCO2) and partial pressure of arterial carbon dioxide (PaCO2) in ventilated newborns. Thirty-one ventilated newborn underwent mainstream PetCO2 monitoring; meanwhile, arterial blood gas analysis was performed. The correlation and consistency between PetCO2 and PaCO2 were assessed. A total of 85 end-tidal and arterial CO2 pairs were obtained from 31 ventilated newborns. The mean PetCO2 (41±10 mm Hg) was significantly lower than the corresponding mean PaCO2 (46±11 mm Hg) (Plimits of consistency, -3.3 to 13.6 mmHg), and 5% (4/85) of the points were beyond the 95%CI. When the oxygenation index (OI) was less than 300 mm Hg (n=48), there was a significant positive correlation between PetCO2 and PaCO2 (r=0.85, Plimits of consistency, -2.6 to 14.5 mm Hg), and 4.2% (2/48) of the points were beyond the 95%CI. When the OI was more than 300 mm Hg (n=37), there was also a significant positive correlation between PetCO2 and PaCO2 (r=0.91, Plimits of consistency, -3.9 to 12.1 mm Hg), and 5% (2/37) of the points were beyond the 95%CI. There is a good correlation and consistency between PetCO2 and PaCO2 in ventilated newborns.

  3. High capacity carbon dioxide sorbent

    Science.gov (United States)

    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.

  4. A unique case of bifid left testicular artery having its anomalous high origin from renal artery

    Directory of Open Access Journals (Sweden)

    Ashwini P Aithal

    2016-01-01

    Full Text Available The testicular arteries are known to originate from the ventrolateral aspect of the abdominal aorta and descend obliquely to the pelvic cavity and supply the testis. An anatomical description of an uncommon variation of the left testicular artery is presented in this case report, highlighting its clinical implications. During routine dissection of a male cadaver, we found that the left testicular artery was bifid and it was arising from the left renal artery. After its origin, it then coursed behind the left renal vein, passed between the left testicular vein and left ureter and at the lower pole of the left kidney, this bifid testicular artery joined to form a single testicular artery which thereafter presented a normal course. Anatomy of the testicular artery has been studied in detail because of its importance in testicular physiology, as well as its significance in testicular and renal surgery. This vascular variation shows a major significance in renal surgery, partial or total nephrectomy, and renal transplant. In addition, this anatomical variation enhances the importance of arteriography or the Doppler ultrasound examination of the renal hilum before surgeries.

  5. Anaesthesia for laparoscopic nephrectomy: Does end-tidal carbon dioxide measurement correlate with arterial carbon dioxide measurement?

    Science.gov (United States)

    Jayan, Nithin; Jacob, Jaya Susan; Mathew, Mohan

    2018-04-01

    Not many studies have explored the correlation between arterial carbon dioxide tension (PaCO 2 ) and end-tidal carbon dioxide tension (ETCO 2 ) in surgeries requiring pneumoperitoneum of more than 1 hour duration with the patient in non-supine position. The aim of our study was to evaluate the correlation of ETCO 2 with PaCO 2 in patients undergoing laparoscopic nephrectomy under general anaesthesia. A descriptive study was performed in thirty patients undergoing laparoscopic nephrectomy from September 2014 to August 2015. The haemodynamic parameters, minute ventilation, PaCO 2 and ETCO 2 measured at three predetermined points during the procedure were analysed. Correlation was checked using Pearson's Correlation Coefficient Test. P <0.05 was considered statistically significant. Statistical analysis of the values showed a positive correlation between ETCO 2 and PaCO 2 ( P < 0.05). Following carbon dioxide insufflation, both ETCO 2 and PaCO 2 increased by 5.4 and 6.63 mmHg, respectively, at the end of the 1 st hour. The PaCO 2 -ETCO 2 gradient was found to increase during the 1 st hour following insufflation (4.07 ± 2.05 mmHg); it returned to the pre-insufflation values in another hour (2.93 ± 1.43 mmHg). Continuous ETCO 2 monitoring is a reliable indicator of the trend in arterial CO 2 fluctuations in the American Society of Anesthesiologists Grades 1 and 2 patients undergoing laparoscopic nephrectomy under general anaesthesia.

  6. Carbon nanomaterials for high-performance supercapacitors

    OpenAIRE

    Tao Chen; Liming Dai

    2013-01-01

    Owing to their high energy density and power density, supercapacitors exhibit great potential as high-performance energy sources for advanced technologies. Recently, carbon nanomaterials (especially, carbon nanotubes and graphene) have been widely investigated as effective electrodes in supercapacitors due to their high specific surface area, excellent electrical and mechanical properties. This article summarizes the recent progresses on the development of high-performance supercapacitors bas...

  7. 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.

  8. Unilateral high bifurcation of brachial artery: a case report | Auwal ...

    African Journals Online (AJOL)

    The Profunda Brachii, Superior Ulnar Collateral and Inferior Ulnar Collateral arteries arose from the relatively short brachial arterial trunk. Although the documented incidence of this anatomical variation is low in Nigeria, its concomitant widespread documentation in other parts of the world makes it a sufficiently important ...

  9. 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.

  10. High-surface-area active carbon

    International Nuclear Information System (INIS)

    O'Grady, T.M.; Wennerberg, A.N.

    1986-01-01

    This paper describes the preparation and properties of a unique active carbon having exceptionally high surface areas, over 2500 m 2 /gm, and extraordinary adsorptive capacities. The carbon is made by a direct chemical activation route in which petroleum coke or other carbonaceous sources are reacted with excess potassium hydroxide at 400 0 to 500 0 C to an intermediate product that is subsequently pyrolyzed at 800 0 to 900 0 C to active carbon containing potassium salts. These are removed by water washing and the carbon is dried to produce a powdered product. A granular carbon can also be made by further processing the powdered carbon by using specialized granulation techniques. Typical properties of the carbon include Iodine Numbers of 3000 to 3600, methylene blue adsorption of 650 to 750 mg/gm, pore volumes of 2.0 to 2.6 cc/gm and less than 3.0% ash. This carbon's high adsorption capacities make it uniquely suited for numerous demanding applications in the medical area, purifications, removal of toxic substances, as catalyst carriers, etc

  11. On high temperature strength of carbon steels

    International Nuclear Information System (INIS)

    Ichinose, Hiroyuki; Tamura, Manabu; Kanero, Takahiro; Ihara, Yoshihito

    1977-01-01

    In the steels for high temperature use, the oxidation resistance is regarded as important, but carbon steels show enough oxidation resistance to be used continuously at the temperature up to 500 deg. C if the strength is left out of consideration, and up to 450 deg. C even when the strength is taken into account. Moreover, the production is easy, the workability and weldability are good, and the price is cheap in carbon steels as compared with alloy steels. In the boilers for large thermal power stations, 0.15-0.30% C steels are used for reheater tubes, main feed water tubes, steam headers, wall water tubes, economizer tubes, bypass pipings and others, and they account for 70% of all steel materials used for the boilers of 350 MW class and 30% in 1000 MW class. The JIS standard for the carbon steels for high temperature use and the related standards in foreign countries are shown. The high temperature strength of carbon steels changes according to the trace elements, melting and heat treatment as well as the main compositions of C, Si and Mn. Al and N affect the high temperature strength largely. The characteristics of carbon steels after the heating for hours, the factors controlling the microstructure and high temperature strength, and the measures to improve the high temperature strength of carbon steels are explained. (Kako, I.)

  12. 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.

  13. High value carbon materials from PET recycling

    International Nuclear Information System (INIS)

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

    2004-01-01

    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 deg. C under CO 2 atmosphere to different burn-off degrees. Textural characterisation of the samples was carried out by performing N 2 adsorption isotherms at -196 deg. C. The obtained carbons materials were mainly microporous, presenting low meso and macroporosity, and apparent BET surface areas of upto 2500 m 2 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

  14. Evaluation of anastomosis between intrahepatic or extrahepatic vessels by intra-arterial digital subtraction angiography using carbon dioxide

    International Nuclear Information System (INIS)

    Miyazono, Nobuaki; Inoue, Hiroki; Ueno, Kazuto; Nishida, Hirotoshi; Kanetsuki, Ichirou; Miyake, Satoshi; Nakajo, Masayuki

    1995-01-01

    Carbon dioxide (CO 2 ) intra-arterial subtraction angiography (IADSA) was performed in 31 patients with various hepatobiliary disease. The injection sites of CO 2 were proper hepatic artery (10/31; group A), segmental hepatic artery (18/31; group B), and peripheral inferior phrenic artery (3/31; group C), respectively. In group A, only the third order branches of the portal venous system were visualized anterogradely in 8 of 10 patients. In group B, the microcatheter was placed coaxially through a 5 French guiding catheter at the main arterial supply of the tumor in 7 patients and at the peripheral segmental branch of the hepatic artery in 11 patients. The portal venous system was visualized retrogradely in all of the patients regardless of the injection site. The injected CO 2 may flow back into the portal vein through the anastmosis known as the peribiliary or periportal plexus. In group C, not only the portal vein but also the pulmonary artery or pericardial vein were visualized by this method. CO 2 -IADSA was useful to image the minute communications between the various vessels, which have been not hitherto visualized by iodinated contrast medium. (author)

  15. Evaluation of anastomosis between intrahepatic or extrahepatic vessels by intra-arterial digital subtraction angiography using carbon dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Miyazono, Nobuaki; Inoue, Hiroki; Ueno, Kazuto; Nishida, Hirotoshi; Kanetsuki, Ichirou; Miyake, Satoshi; Nakajo, Masayuki [Kagoshima Univ. (Japan). Faculty of Medicine

    1995-04-01

    Carbon dioxide (CO{sub 2}) intra-arterial subtraction angiography (IADSA) was performed in 31 patients with various hepatobiliary disease. The injection sites of CO{sub 2} were proper hepatic artery (10/31; group A), segmental hepatic artery (18/31; group B), and peripheral inferior phrenic artery (3/31; group C), respectively. In group A, only the third order branches of the portal venous system were visualized anterogradely in 8 of 10 patients. In group B, the microcatheter was placed coaxially through a 5 French guiding catheter at the main arterial supply of the tumor in 7 patients and at the peripheral segmental branch of the hepatic artery in 11 patients. The portal venous system was visualized retrogradely in all of the patients regardless of the injection site. The injected CO{sub 2} may flow back into the portal vein through the anastmosis known as the peribiliary or periportal plexus. In group C, not only the portal vein but also the pulmonary artery or pericardial vein were visualized by this method. CO{sub 2}-IADSA was useful to image the minute communications between the various vessels, which have been not hitherto visualized by iodinated contrast medium. (author).

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

    Science.gov (United States)

    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%.

  17. Cubic martensite in high carbon steel

    Science.gov (United States)

    Chen, Yulin; Xiao, Wenlong; Jiao, Kun; Ping, Dehai; Xu, Huibin; Zhao, Xinqing; Wang, Yunzhi

    2018-05-01

    A distinguished structural characteristic of martensite in Fe-C steels is its tetragonality originating from carbon atoms occupying only one set of the three available octahedral interstitial sites in the body-centered-cubic (bcc) Fe lattice. Such a body-centered-tetragonal (bct) structure is believed to be thermodynamically stable because of elastic interactions between the interstitial carbon atoms. For such phase stability, however, there has been a lack of direct experimental evidence despite extensive studies of phase transformations in steels over one century. In this Rapid Communication, we report that the martensite formed in a high carbon Fe-8Ni-1.26C (wt%) steel at room temperature induced by applied stress/strain has actually a bcc rather than a bct crystal structure. This finding not only challenges the existing theories on the stability of bcc vs bct martensite in high carbon steels, but also provides insights into the mechanism for martensitic transformation in ferrous alloys.

  18. Arterial stiffness in junior high school students: Longitudinal observations.

    Science.gov (United States)

    Fujiwara, Hiroshi; Nakajima, Hisakazu; Inoue, Fumio; Kosaka, Kitaro; Asano, Hiroaki; Yoshii, Kengo

    2018-02-01

    Early atherosclerotic change is found even in childhood, and there is an urgent need to clarify the factors causing childhood atherosclerosis and take preventive measures. Early detection of the contributing risk factors is crucial to facilitate preventive measures. Pulse wave velocity (PWV) is a widely used technique for the assessment of atherosclerosis in children. Lifestyle questionnaire, brachio-ankle PWV (baPWV) and anthropometric data were obtained from junior high school students in an urban area of Japan between 2006 and 2008, from seventh to ninth grades. Mean baPWV increased from 867.4 ± 99.5 m/s to 944.5 ± 117.5 m/s in boys, and from 864.0 ± 99.5 m/s to 923.0 ± 101.3 m/s in girls. Obese students had higher baPWV than non-obese students in both genders across each grade. On logistic regression analysis of ninth grade student data, high baPWV was dependent on systolic blood pressure (SBP), time watching television (TV) and symptoms of depression and anxiety, whereas low baPWV was dependent on time playing video games, light exercise, sleep and indoor play, as well as good friendship and motivation. Systolic blood pressure, time watching TV, and symptoms of depression and anxiety may contribute to arterial stiffness and be related to obesity in junior high school students. © 2017 The Authors Pediatrics International published by John Wiley & Sons Australia, Ltd on behalf of Japan Pediatric Society.

  19. 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....

  20. A case of atherosclerotic inferior mesenteric artery aneurysm secondary to high flow state.

    Science.gov (United States)

    Troisi, Nicola; Esposito, Giovanni; Cefalì, Pietro; Setti, Marco

    2011-07-01

    Inferior mesenteric artery aneurysms are very rare and they are among the rarest of visceral artery aneurysms. Sometimes, the distribution of the blood flow due to chronic atherosclerotic occlusion of some arteries can establish an increased flow into a particular supplying district (high flow state). A high flow state in a stenotic inferior mesenteric artery in compensation for a mesenteric occlusive disease can produce a rare form of aneurysm. We report the case of an atherosclerotic inferior mesenteric aneurysm secondary to high flow state (association with occlusion of the celiac trunk and severe stenosis of the superior mesenteric artery), treated by open surgical approach. Copyright © 2011 Society for Vascular Surgery. Published by Mosby, Inc. All rights reserved.

  1. Brachial artery protected by wrapped latissimus dorsi muscle flap in high voltage electrical injury

    Science.gov (United States)

    Gencel, E.; Eser, C.; Kokacya, O.; Kesiktas, E.; Yavuz, M.

    2016-01-01

    Summary High voltage electrical injury can disrupt the vascular system and lead to extremity amputations. It is important to protect main vessels from progressive burn necrosis in order to salvage a limb. The brachial artery should be totally isolated from the burned area by a muscle flap to prevent vessel disruption. In this study, we report the use of a wrap-around latissimus dorsi muscle flap to protect a skeletonized brachial artery in a high voltage electrical injury in order to salvage the upper extremity and restore function. The flap wrapped around the exposed brachial artery segment and luminal status of the artery was assessed using magnetic resonance angiography. No vascular intervention was required. The flap survived completely with good elbow function. Extremity amputation was not encountered. This method using a latissimus dorsi flap allows the surgeon to protect the main upper extremity artery and reconstruct arm defects, which contributes to restoring arm function in high voltage electrical injury. PMID:28149236

  2. 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.

  3. Arterial blood gas management in retrograde cerebral perfusion: the importance of carbon dioxide.

    Science.gov (United States)

    Ueno, K; Takamoto, S; Miyairi, T; Morota, T; Shibata, K; Murakami, A; Kotsuka, Y

    2001-11-01

    Many interventional physiological assessments for retrograde cerebral perfusion (RCP) have been explored. However, the appropriate arterial gas management of carbon dioxide (CO2) remains controversial. The aim of this study is to determine whether alpha-stat or pH-stat could be used for effective brain protection under RCP in terms of cortical cerebral blood flow (CBF), cerebral metabolic rate for oxygen (CMRO2), and distribution of regional cerebral blood flow. Fifteen anesthetized dogs (25.1+/-1.1 kg) on cardiopulmonary bypass (CPB) were cooled to 18 degrees C under alpha-stat management and had RCP for 90 min under: (1), alpha-stat; (2), pH-stat; or (3), deep hypothermic (18 degrees C) antegrade CPB (antegrade). RCP flow was regulated for a sagittal sinus pressure of around 25 mmHg. CBF was monitored by a laser tissue flowmeter. Serial analyses of blood gas were made. The regional cerebral blood flow was measured with colored microspheres before discontinuation of RCP. CBF and CMRO2 were evaluated as the percentage of the baseline level (%CBF, %CMRO2). The oxygen content of arterial inflow and oxygen extraction was not significantly different between the RCP groups. The %CBF and %CMRO2 were significantly higher for pH-stat RCP than for alpha-stat RCP. The regional cerebral blood flow, measured with colored microspheres, tended to be higher for pH-stat RCP than for alpha-stat RCP, at every site in the brain. Irrespective of CO2 management, regional differences were not significant among any site in the brain. CO2 management is crucial for brain protection under deep hypothermic RCP. This study revealed that pH-stat was considered to be better than alpha-stat in terms of CBF and oxygen metabolism in the brain. The regional blood flow distribution was considered to be unchanged irrespective of CO2 management.

  4. High Origin of Radial Arteries: A Report of Two Rare Cases

    Directory of Open Access Journals (Sweden)

    Dong Zhan

    2010-01-01

    Full Text Available Variations in the arterial supply of the upper limb are relatively common, with reported prevalence rates ranging from 11 to 24.4%. Of these, the most commonly encountered variation in the arm is a high origin of the radial artery. However, after consecutively dissecting and examining 600 Singaporean Chinese cadavers (1,200 upper limbs, we found only two cases of this. In both cases, the brachioradial artery originated from the upper one-third of the brachial artery and continued distally as the radial artery in the forearm. The local prevalence of 0.33% of this variation is significantly lower compared against populations from other geographical regions. Although rare, recognition of the variation is of fundamental importance to clinical practice.

  5. Synthesis of high luminescent carbon nanoparticles

    Science.gov (United States)

    Gvozdyuk, Alina A.; Petrova, Polina S.; Goryacheva, Irina Y.; Sukhorukov, Gleb B.

    2017-03-01

    In this article we report an effective and simple method for synthesis of high luminescent carbon nanodots (CDs). In our work as a carbon source sodium dextran sulfate (DS) was used because it is harmless, its analogs are used in medicine as antithrombotic compounds and blood substitutes after hemorrhage. was used as a substrate We investigated the influence of temperature parameters of hydrothermal synthesis on the photoluminescence (PL) intensity and position of emission maxima. We discovered that the PL intensity can be tuned by changing of synthesis temperature and CD concentration.

  6. High value carbon materials from PET recycling

    Energy Technology Data Exchange (ETDEWEB)

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

    2004-11-15

    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 deg. C under CO{sub 2} atmosphere to different burn-off degrees. Textural characterisation of the samples was carried out by performing N{sub 2} adsorption isotherms at -196 deg. C. The obtained carbons materials were mainly microporous, presenting low meso and macroporosity, and apparent BET surface areas of upto 2500 m{sup 2} g{sup -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.

  7. Utilisation of high carbon pulverised fuel ash

    OpenAIRE

    Mahmud, Maythem Naji

    2011-01-01

    Coal combustion by-products generated from coal-fired power plant and cause enormous problems for disposal unless a way can be found to utilize these by-products through resource recovery programs. The implementation of air act regulations to reduce NOx emission have resulted millions of tonnes of pulverised fuel ash (PFA) accumulated with high percentage of unburned carbon made it un-saleable for the cement industry. Moreover, alternative fuels such as biomass and import coals were suggested...

  8. Autofluorescence and high-definition optical coherence tomography of retinal artery occlusions

    OpenAIRE

    Mathew, Raeba; Papavasileiou, Evangelia; Sivaprasad, Sobha

    2010-01-01

    Raeba Mathew, Evangelia Papavasileiou, Sobha SivaprasadLaser and Retinal Research Unit, Department of Ophthalmology, King’s College Hospital, Denmark Hill, London, UKBackground: The purpose of this study is to illustrate the fundus autofluorescence and high-definition optical coherence tomography (HD-OCT) features of acute and long-standing retinal artery occlusions.Design: Retrospective case series.Participants: Patients with acute and chronic retinal and cilioretinal artery occlus...

  9. 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)

  10. High activity carbon sorbents for mercury capture

    Directory of Open Access Journals (Sweden)

    Stavropoulos George G.

    2006-01-01

    Full Text Available 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 N2 adsorption at 77 K. 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.

  11. 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.

  12. Studies on reconstruction of the carotid artery in the neck using arterial vessels irradiated by a large amount of high voltage electron beam

    International Nuclear Information System (INIS)

    Matsumura, Hiroshi

    1978-01-01

    High voltage electron beam of 2,000,000 rad was irradiated to the common carotid arteries excised from dogs. After keeping them in a frozen state, they were replaced with the common carotid arteries of other adult dogs. The border of the artery transplanted could not be identified from the x-ray films 7 - 36 months after transplantation. There was no stenosis or dilation in the artery on either x-ray films or in histopathological examinations. There was no tissue reaction in the homologous transplantation, but all the cells died and the nuclei of muscular fibers of the tunica media disappeared. However, the internal elastica and other elastic fibers were unchanged. Cells proliferated from the original artery to form a false inner coat. Noradrenergic nerves and the vasa vasorum did not enter the graft. Thus, the arteries transplanted were only substitutive vessels. A rabbit abdominal aorta which was transplanted to a dog common carotid artery, showed sacculated dilation or obstruction. In the case of obstruction, severe tissue reaction was recognized. In the case of sacculated dilation, thinning of the arterial wall at the dilated part and fragmentation of the elastic fibers of the tunica media were observed, and other tissues also tended to be destructed and absorbed. (Ichikawa, K.)

  13. Ultra-high-resolution CT angiography of the artery of Adamkiewicz. A feasibility study

    Energy Technology Data Exchange (ETDEWEB)

    Yoshioka, Kunihiro; Tanaka, Ryoichi; Takagi, Hidenobu [Iwate Medical University, Division of Cardiovascular Radiology, Department of Radiology, Morioka (Japan); Ueyama, Yuta; Kikuchi, Kei; Chiba, Takuya [Iwate Medical University Hospital, Center for Radiological Science, Morioka (Japan); Arakita, Kazumasa [Center for Medical Research and Development, Toshiba Medical Systems Corporation, Otawara (Japan); Schuijf, Joanne D. [Center for Medical Research and Development Europe, Toshiba Medical Systems Europe, Zoetermeer (Netherlands); Saito, Yasuo [CT Systems Development Department, Toshiba Medical Systems Corporation, Otawara (Japan)

    2018-01-15

    Preoperative identification of the artery of Adamkiewicz can help prevent postoperative spinal cord injury following thoracic and thoracoabdominal aortic repair. Several studies have demonstrated the feasibility of evaluating the artery of Adamkiewicz using multi-detector row computed tomography (CT), but precise visualization remains a challenge. The present study was conducted to evaluate the usefulness of ultra-high-resolution CT for visualizing the artery of Adamkiewicz with a slice thickness of 0.25 versus 0.5 mm in patients with aortic aneurysms. Our institutional review board approved this study. Twenty-four patients with thoracic and thoracoabdominal aneurysms were scanned with beam collimation of 0.25 mm x 128. Images were reconstructed with slice thicknesses of 0.25 and 0.5 mm. The signal-to-noise ratio (SNR) of the aorta and contrast-to-noise ratio (CNR) between the anterior spinal artery and spinal cord were measured. Two independent observers evaluated visualization of the artery of Adamkiewicz and its continuity between the anterior spinal artery and the aorta using a four-point scale. No significant differences in the SNR of the aorta or CNR of the anterior spinal artery were observed between 0.25- and 0.5-mm slices. The average visualization score was significantly higher for 0.25-mm slices (3.58 ± 0.78) than for 0.5-mm slices (3.13 ± 0.99) (p = 0.01). The percentage of patients with nondiagnostic image quality was significantly lower for 0.25-mm slices (8.3%) than for 0.5-mm slices (33.3%) (p = 0.03). In patients with aortic aneurysms, ultra-high-resolution CT with 0.25-mm slices significantly improves visualization of the artery of Adamkiewicz compared to 0.5-mm slices. (orig.)

  14. 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) ...

  15. Respiratory sinus arrhythmia stabilizes mean arterial blood pressure at high-frequency interval in healthy humans.

    Science.gov (United States)

    Elstad, Maja; Walløe, Lars; Holme, Nathalie L A; Maes, Elke; Thoresen, Marianne

    2015-03-01

    Arterial blood pressure variations are an independent risk factor for end organ failure. Respiratory sinus arrhythmia (RSA) is a sign of a healthy cardiovascular system. However, whether RSA counteracts arterial blood pressure variations during the respiratory cycle remains controversial. We restricted normal RSA with non-invasive intermittent positive pressure ventilation (IPPV) to test the hypothesis that RSA normally functions to stabilize mean arterial blood pressure. Ten young volunteers were investigated during metronome-paced breathing and IPPV. Heart rate (ECG), mean arterial blood pressure and left stroke volume (finger arterial pressure curve) and right stroke volume (pulsed ultrasound Doppler) were recorded, while systemic and pulmonary blood flow were calculated beat-by-beat. Respiratory variations (high-frequency power, 0.15-0.40 Hz) in cardiovascular variables were estimated by spectral analysis. Phase angles and correlation were calculated by cross-spectral analysis. The magnitude of RSA was reduced from 4.9 bpm(2) (95% CI 3.0, 6.2) during metronome breathing to 2.8 bpm(2) (95% CI 1.1, 5.0) during IPPV (p = 0.03). Variations in mean arterial blood pressure were greater (2.3 mmHg(2) (95% CI 1.4, 3.9) during IPPV than during metronome breathing (1.0 mmHg(2) [95% CI 0.7, 1.3]) (p = 0.014). Respiratory variations in right and left stroke volumes were inversely related in the respiratory cycle during both metronome breathing and IPPV. RSA magnitude is lower and mean arterial blood pressure variability is greater during IPPV than during metronome breathing. We conclude that in healthy humans, RSA stabilizes mean arterial blood pressure at respiratory frequency.

  16. Carbon nanotubes for high-performance logic

    OpenAIRE

    Chen, Zhihong; Wong, H.S. Phillip; Mitra, Subhasish; Bol, Aggeth; Peng, Lianmao; Hills, Gage; Thissen, Nick

    2014-01-01

    Single-wall carbon nanotubes (CNTs) were discovered in 1993 and have been an area of intense research since then. They offer the right dimensions to explore material science and physical chemistry at the nanoscale and are the perfect system to study low-dimensional physics and transport. In the past decade, more attention has been shifted toward making use of this unique nanomaterial in real-world applications. In this article, we focus on potential applications of CNTs in the high-performanc...

  17. 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.

  18. Nitrogen in highly crystalline carbon nanotubes

    International Nuclear Information System (INIS)

    Ducati, C; Koziol, K; Stavrinadis, A; Friedrichs, S; Windle, A H; Midgley, P A

    2006-01-01

    Multiwall carbon nanotubes (MWCNTs) with an unprecedented degree of internal order were synthesised by chemical vapour deposition (CVD) adding a nitrogen-containing compound to the hydrocarbon feedstock. Ferrocene was used as the metal catalyst precursor. The remarkable crystallinity of these nanotubes lies both in the isochirality and in the crystallographic register of their walls, as demonstrated by electron diffraction and high resolution electron microscopy experiments. High resolution transmission electron microscopy analysis shows that the walls of the nanotubes consist of truncated stacked cones, instead of perfect cylinders, with a range of apex angles that appears to be related to the nitrogen concentration in the synthesis process. The structure of armchair, zigzag and chiral nanotubes is modelled and discussed in terms of density of topological defects, providing an interesting comparison with our microscopy experiments. A growth mechanism based on the interplay of base- and tip-growth is proposed to account for our experimental observations

  19. Autofluorescence and high-definition optical coherence tomography of retinal artery occlusions

    Directory of Open Access Journals (Sweden)

    Raeba Mathew

    2010-10-01

    Full Text Available Raeba Mathew, Evangelia Papavasileiou, Sobha SivaprasadLaser and Retinal Research Unit, Department of Ophthalmology, King’s College Hospital, Denmark Hill, London, UKBackground: The purpose of this study is to illustrate the fundus autofluorescence and high-definition optical coherence tomography (HD-OCT features of acute and long-standing retinal artery occlusions.Design: Retrospective case series.Participants: Patients with acute and chronic retinal and cilioretinal artery occlusions are included in this series.Methods: A detailed clinical examination, color fundus photographs, autofluorescence, and HD-OCT of the subjects were performed.Results: HD-OCT demonstrates the localized and well-demarcated thickening of the inner retina in the acute phase of arterial occlusions that correlates with the areas of blocked autofluorescence caused by the cloudy swelling of the retina. The areas of blocked autofluorescence disappear with chronicity of the disease and this corresponds to the thinning of the inner retinal layers on HD-OCT.Conclusion: Heidelberg OCT and autofluorescence are useful tools to assess retinal arterial occlusions especially in subjects with unexplained visual field loss.Keywords: autofluorescence, high definition OCT, retinal artery occlusion

  20. Failure Modes of a Unidirectional Ultra-High-Modulus Carbon-Fiber/Carbon-Matrix Composite

    National Research Council Canada - National Science Library

    Zaldivar, R

    1998-01-01

    The objective of this study was to observe the effects of various microstructural features on the in situ, room-temperature tensile fracture behavior of an ultra-high-modulus, unidirectional carbon/carbon (C/C...

  1. Thermal Oxidation of a Carbon Condensate Formed in High-Frequency Carbon and Carbon-Nickel Plasma Flow

    Science.gov (United States)

    Churilov, G. N.; Nikolaev, N. S.; Cherepakhin, A. V.; Dudnik, A. I.; Tomashevich, E. V.; Trenikhin, M. V.; Bulina, N. G.

    2018-02-01

    We have reported on the comparative characteristics of thermal oxidation of a carbon condensate prepared by high-frequency arc evaporation of graphite rods and a rod with a hollow center filled with nickel powder. In the latter case, along with different forms of nanodisperse carbon, nickel particles with nickel core-carbon shell structures are formed. It has been found that the processes of the thermal oxidation of carbon condensates with and without nickel differ significantly. Nickel particles with the carbon shell exhibit catalytic properties with respect to the oxidation of nanosized carbon structures. A noticeable difference between the temperatures of the end of the oxidation process for various carbon nanoparticles and nickel particles with the carbon shell has been established. The study is aimed at investigations of the effect of nickel nanoparticles on the dynamics of carbon condensate oxidation upon heating in the argon-oxygen flow.

  2. Asymmetric Bilateral Variations in the Musculocutaneous and Median Nerves with High Branching of Brachial Artery

    Directory of Open Access Journals (Sweden)

    Vandana Tomar

    2012-01-01

    Full Text Available Brachial Plexus is formed by the union of the anterior rami of cervical 5, 6, 7, 8 and thoracic 1 nerves. These nerves unite and divide to form the key nerves innervating the upper limb. Variations in the course of these nerves are clinically important to anesthetists, neurologists and orthopedicians. We report bilateral variations in the arterial and neural structures in the upper limb of a 65 year old cadaver. The muscles of the arm on one side were innervated by the median nerve with absence of musculocutaneous. While on the other side the musculocutaneous nerve contributed to the formation of the median nerve. There was a presence of high bifurcation of brachial artery on both sides. Knowledge of such variations in the innervations of muscles and the arterial supply of the limbs are important to remember before performing any reconstructive procedures or interventions on the limb.

  3. 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...

  4. Highly thermal conductive carbon fiber/boron carbide composite material

    International Nuclear Information System (INIS)

    Chiba, Akio; Suzuki, Yasutaka; Goto, Sumitaka; Saito, Yukio; Jinbo, Ryutaro; Ogiwara, Norio; Saido, Masahiro.

    1996-01-01

    In a composite member for use in walls of a thermonuclear reactor, if carbon fibers and boron carbide are mixed, since they are brought into contact with each other directly, boron is reacted with the carbon fibers to form boron carbide to lower thermal conductivity of the carbon fibers. Then, in the present invention, graphite or amorphous carbon is filled between the carbon fibers to provide a fiber bundle of not less than 500 carbon fibers. Further, the surface of the fiber bundle is coated with graphite or amorphous carbon to suppress diffusion or solid solubilization of boron to carbon fibers or reaction of them. Then, lowering of thermal conductivity of the carbon fibers is prevented, as well as the mixing amount of the carbon fiber bundles with boron carbide, a sintering temperature and orientation of carbon fiber bundles are optimized to provide a highly thermal conductive carbon fiber/boron carbide composite material. In addition, carbide or boride type short fibers, spherical graphite, and amorphous carbon are mixed in the boron carbide to prevent development of cracks. Diffusion or solid solubilization of boron to carbon fibers is reduced or reaction of them if the carbon fibers are bundled. (N.H.)

  5. Prevalence Study of Proximal Vertebral Artery Stenosis Using High-Resolution Contrast-Enhanced Magnetic Resonance Angiography

    International Nuclear Information System (INIS)

    Kim, S.H.; Lee, J.S.; Kwon, O.K.; Han, M.K.; Kim, J.H.

    2005-01-01

    Purpose: To evaluate the prevalence of proximal vertebral artery stenosis, compared with those of the distal vertebral/basilar artery and extracranial internal carotid artery, in a large population of stroke and non-stroke patients. Material and Methods: Nine-hundred-and-thirty-five patients who underwent high-resolution contrast-enhanced magnetic resonance angiography in a regional general hospital were categorized into six groups based on neurological symptoms and disease: an asymptomatic group (n ∼ 182), a minor symptom group with headache or dizziness (n ∼ 519), a cardiac group with coronary artery steno-occlusive disease (n ∼ 15), a hemorrhagic group with old cerebral hemorrhage (n ∼ 26), an anterior circulation infarct group (n ∼ 121), and posterior circulation infarct group (n ∼ 72). Prevalence of stenosis of the proximal vertebral artery, distal vertebral/basilar artery, and internal carotid artery was analyzed. Results: The prevalence of stenosis of the proximal vertebral artery, distal vertebral/basilar artery, and internal carotid artery was 12.9%, 5.5%, and 7.2%, respectively, in the study population, and rose as the age increased (P <0.0001 for all arteries). The prevalence of stenosis of the proximal vertebral artery, distal vertebral/basilar artery, and internal carotid artery was 3.3%, 0.5%, and.1%, respectively, in the asymptomatic group; 8.3%, 2.1%, and 3.7%, respectively, in the minor symptom group; 13.3%, 6.7%, and 6.7%, respectively, in the cardiac group; 19.2%, 7.7%, and 7.7%, respectively, in the hemorrhagic group; 27.3%, 8.3%, and 25.6%, respectively, in the anterior circulation infarct group; and 44.4%, 36.1%, and 16.7%, respectively, in the posterior circulation infarct group. This increasing tendency of stenosis accordingly was statistically significant ( P <0.0001 for all arteries). Conclusion: The prevalence of proximal vertebral artery stenosis was highest, compared with those of the distal vertebral/basilar artery and

  6. Carbon Dioxide Mitigation Benefit of High-Speed Railway in Terms of Carbon Tax

    Directory of Open Access Journals (Sweden)

    Fu Yanbing

    2013-01-01

    Full Text Available This paper calculates the carbon dioxide mitigation benefit of high-speed railway based on the carbon dioxide tax policy. We define the carbon dioxide emission system boundary for high-speed railway in its whole life cycle and estimate the life cycle carbon dioxide inventories during its construction, application, and recovery stages. And then we establish a theoretical model to calculate the life cycle carbon dioxide mitigation quantity for high-speed railway when compared with road transport and then calculate its carbon dioxide mitigation benefit. The numerical example shows that the carbon dioxide mitigation benefit of high-speed railway is better than that of road transport from the whole life cycle perspective.

  7. 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.

  8. Denervation of pulmonary artery during mitral valve surgery in patients with high pulmonary hypertension

    Directory of Open Access Journals (Sweden)

    А. В. Богачев-Прокофьев

    2016-01-01

    Full Text Available Objective. Pulmonary hypertension impairs the mitral valve and often leads to more severe symptoms of heart failure, low exercise tolerance and thus higher rates of morbidity and mortality. The purpose of this study is to evaluate the safety and efficacy of simultaneous radiofrequency ablation of ganglionated plexi of the pulmonary artery in patients with high pulmonary hypertension during mitral valve surgery.Methods. The inclusion criteria were based on patients’ echocardiography/right heart catheterization data. The main criteria were mean pulmonary artery pressure ≥40 mm Hg at rest and a positive reactive test with nitric oxide inhalation. From January 2014 to May 2015, 14 patients underwent radiofrequency denervation of the pulmonary artery in addition to planned mitral valve surgery. Mean patient age was 53.4±7.8 years, with 57.1% of patients being females.Results. Mean cardiopulmonary bypass time was 116±12 minutes, mean cross-clamp time was 95±13 minutes, and mean ablation time amounted to 9.5±3.1 minutes. Pulmonary artery pressure decreased significantly from a mean of 56.5±9.8 mmHg to 32.0±7.3 mmHg immediately after the operation (p<0.001, and to 28.4±5.2 mmHg and 29.7±4.4 mmHg on the first and third days at ICU respectively. Mean ICU stay was 3.1±1.2 days. There were neither early deaths nor specific complications.Conclusions. Simultaneous radiofrequency ablation of pulmonary artery ganglionated plexi when performing mitral valve surgery in patients with pulmonary hypertension is a safe and effective procedure. Further research and long-term follow-up would help to determine whether a decrease in the mean pressure of the pulmonary artery can be interpreted as a clinical advantage.

  9. Palygorskite Hybridized Carbon Nanocomposite as a High ...

    African Journals Online (AJOL)

    TEM and XRD results showed that acid treatment had an effective impact on ... The electrochemical results showed that the addition of palygorskite into the carbon facilitated the formation of OHads or Oads on the ... and cost-efficient way to improve the electrocatalytic performance of carbon ... AJOL African Journals Online.

  10. Effect of high pressurized carbon dioxide on Escherichia coli ...

    African Journals Online (AJOL)

    Carbon dioxide at high pressure can retard microbial growth and sometimes kill microorganisms depending on values of applied pressure, temperature and exposure time. In this study the effect of high pressurised carbon dioxide (HPCD) on Escherichia coli was investigated. Culture of E. coli was subjected to high ...

  11. High-resolution flow imaging of the carotid arteries

    International Nuclear Information System (INIS)

    Masaryk, T.J.; Modic, M.T.; Haacke, E.M.; Lenz, G.W.; Ross, J.S.

    1986-01-01

    Recently, high-contrast vascular images have been demonstrated using short TEs, gating and subtraction. However, to obtain short TE values, large gradients are required. This potentially limits the field of view, signal-to-noise- ratio, and resolution. Furthermore, gating in different parts of the cardiac cycle can lead to pixel misregistration. In this study, additional refocusing gradients were applied so that no velocity-dependent dephasing occurs at the echo restoring signal from moving blood. Two cardiac-gated sequences using the same trigger delay and one acquisition were obtained. Preliminary results indicate that good quality vascular images of the carotid bifurcation can be obtained with modifications of the spin-echo technique of with short TEs utilizing a gradient echo technique

  12. Bonding Unidirectional Carbon Nanotube with Carbon for High Performance

    Science.gov (United States)

    2015-06-24

    samples in a dilute aqueous solution of AgNO3 and placing them under a UV lamp . After 30 minutes of UV exposure, an obvious color change from black...purposefully avoided due to the potential damages to CNTs and the uncertainty on their effect on carbonization. Millimeter-long CNTs were used to develop...inter-connected network of the sheet, which led to foam-like recovery of the structure after compression. The ACNT/C foams can be tuned by changing

  13. High-Flux Carbon Molecular Sieve Membranes for Gas Separation.

    Science.gov (United States)

    Richter, Hannes; Voss, Hartwig; Kaltenborn, Nadine; Kämnitz, Susanne; Wollbrink, Alexander; Feldhoff, Armin; Caro, Jürgen; Roitsch, Stefan; Voigt, Ingolf

    2017-06-26

    Carbon membranes have great potential for highly selective and cost-efficient gas separation. Carbon is chemically stable and it is relative cheap. The controlled carbonization of a polymer coating on a porous ceramic support provides a 3D carbon material with molecular sieving permeation performance. The carbonization of the polymer blend gives turbostratic carbon domains of randomly stacked together sp 2 hybridized carbon sheets as well as sp 3 hybridized amorphous carbon. In the evaluation of the carbon molecular sieve membrane, hydrogen could be separated from propane with a selectivity of 10 000 with a hydrogen permeance of 5 m 3 (STP)/(m 2 hbar). Furthermore, by a post-synthesis oxidative treatment, the permeation fluxes are increased by widening the pores, and the molecular sieve carbon membrane is transformed from a molecular sieve carbon into a selective surface flow carbon membrane with adsorption controlled performance and becomes selective for carbon dioxide. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. 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

    OBJECTIVES: To test if cardiac computed tomography angiography (CCTA) can be used in the triage of patients at high risk of coronary artery disease. DESIGN: The diagnostic value of 64-detector CCTA was evaluated in 400 patients presenting with non-ST segment elevation myocardial infarction using...... invasive coronary angiography (ICA) as the reference method. The relation between the severity of disease by CCTA and a combined endpoint of death, re-hospitalization due to new myocardial infarction, or symptom-driven coronary revascularization was assessed. RESULTS: CCTA detects significant (>50...... 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....

  15. High efficiency carbon nanotube thread antennas

    Science.gov (United States)

    Amram Bengio, E.; Senic, Damir; Taylor, Lauren W.; Tsentalovich, Dmitri E.; Chen, Peiyu; Holloway, Christopher L.; Babakhani, Aydin; Long, Christian J.; Novotny, David R.; Booth, James C.; Orloff, Nathan D.; Pasquali, Matteo

    2017-10-01

    Although previous research has explored the underlying theory of high-frequency behavior of carbon nanotubes (CNTs) and CNT bundles for antennas, there is a gap in the literature for direct experimental measurements of radiation efficiency. These measurements are crucial for any practical application of CNT materials in wireless communication. In this letter, we report a measurement technique to accurately characterize the radiation efficiency of λ/4 monopole antennas made from the CNT thread. We measure the highest absolute values of radiation efficiency for CNT antennas of any type, matching that of copper wire. To capture the weight savings, we propose a specific radiation efficiency metric and show that these CNT antennas exceed copper's performance by over an order of magnitude at 1 GHz and 2.4 GHz. We also report direct experimental observation that, contrary to metals, the radiation efficiency of the CNT thread improves significantly at higher frequencies. These results pave the way for practical applications of CNT thread antennas, particularly in the aerospace and wearable electronics industries where weight saving is a priority.

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

    Science.gov (United States)

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

    2018-01-01

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

  17. High prevalence of vertebral artery tortuosity of Loeys-Dietz syndrome in comparison with Marfan syndrome

    International Nuclear Information System (INIS)

    Kono, Atsushi K.; Higashi, Masahiro; Tsutsumi, Yoshiaki; Akutsu, Koichi; Naito, Hiroaki; Morisaki, Hiroko; Morisaki, Takayuki; Sugimura, Kazuro

    2010-01-01

    Loeys-Dietz syndrome (LDS) is a connective tissue disease caused by mutations in the genes encoding the transforming growth factor-β receptor (TGFBR). LDS is associated with aneurysms or dissections of the aorta similar to Marfan syndrome (MFS) as well as arterial tortuosity and aneurysms in the peripheral arteries. The purpose of this study was to evaluate the arterial diseases of LDS to differentiate it from MFS. A total of 10 LDS patients with an identified mutation in TGFBR (6 male, 4 female; mean age 36.3 years) and 20 MFS patients with an identified mutation in fibrilin-1 who were age- and sex-matched to the LDS subjects (12 male, 8 female; mean age 37.1 years) were reviewed. The prevalence of vertebral arterial tortuosity (VAT) and peripheral aneurysm (PAN) was studied using computed tomography angiography. In all, 9 of the 10 LDS patients had VAT, and five PANs were observed in 3 patients. In contrast, 8 (40%) of the MFS patients had VAT, and 1 patient had a PAN. LDS had a higher prevalence of VAT (P=0.017) by Fisher's exact test. The VAT was highly prevalent among LDS patients. Thus, the presence of VAT has the potential to differentiate LDS from MFS. (author)

  18. The high opening of the right bronchial artery with a non-typical course.

    Science.gov (United States)

    Maciejewski, R; Madej, B; Anasiewicz, A

    1995-01-01

    Authors describing the bronchial vessels agree to the fact that they are characterised by a great variability in regard to their number and the place where they leave aorta (1, 2, 6). The characteristic feature of the right bronchial artery is that it often forms common trunks with other vessels (mainly with the first right aortic intercostal branch or with one of the upper oesophageal arteries). It can also have a common let-out trunk with the left upper bronchial artery (4). Bearing in mind that the operations on trachea and bronchi are difficult, and that it is very important to maintain the blood supply of the walls in the operated organs we have decided to publish our observations. They refer to a case, not described before, in which the right bronchial artery left the aortic arch in a high position making the vascular supply to the front lower half of the trachea and its bifurcation. Then, it went down to the membranous part of the right bronchus.

  19. 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...

  20. A high-performance carbon derived from polyaniline for supercapacitors

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Jun [Harbin Engineering University, Harbin (China). Key Laboratory of Superlight Materials and Surface Technology; College of Automation, Harbin Engineering University, Harbin (China); Wei, Tong; Fan, Zhuangjun; Li, Tianyou [Harbin Engineering University, Harbin (China). Key Laboratory of Superlight Materials and Surface Technology; Qiao, Wenming [Harbin Engineering University, Harbin (China). Coll. of Material Science and Chemical Engineering; Zhang, Lijun; Zhao, Qiankun [College of Automation, Harbin Engineering University, Harbin (China)

    2010-10-15

    Activated carbon derived from rod-shaped polyaniline (the diameter of 170 nm) was synthesized by carbonization and subsequent activation with KOH. The obtained activated carbon exhibits a high specific capacitance (455 F g{sup -1}) and remarkable rate capability due to its high specific surface area (1976 m{sup 2}g{sup -1}), narrow pore size distribution (< 3 nm) as well as short diffusion length. It is indicated that the promising synthetic method used in this work can pave the way for designing new carbon based materials from different polymers for high-performance energy applications. (author)

  1. A critical appraisal of the use of umbilical artery Doppler ultrasound in high-risk pregnancies: use of meta-analyses in evidence-based obstetrics

    DEFF Research Database (Denmark)

    Westergaard, H.B.; Langhoff-Roos, J.; Lingman, G.

    2001-01-01

    Doppler velocimetry; high-risk pregnancy; meta-analysis; intrauterine growth restriction; perinatal mortality; umbilical artery......Doppler velocimetry; high-risk pregnancy; meta-analysis; intrauterine growth restriction; perinatal mortality; umbilical artery...

  2. 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...

  3. High-Intensity Statin Therapy Is Associated With Improved Survival in Patients With Peripheral Artery Disease.

    Science.gov (United States)

    Foley, T Raymond; Singh, Gagan D; Kokkinidis, Damianos G; Choy, Ho-Hin K; Pham, Thai; Amsterdam, Ezra A; Rutledge, John C; Waldo, Stephen W; Armstrong, Ehrin J; Laird, John R

    2017-07-15

    The relative benefit of higher statin dosing in patients with peripheral artery disease has not been reported previously. We compared the effectiveness of low- or moderate-intensity (LMI) versus high-intensity (HI) statin dose on clinical outcomes in patients with peripheral artery disease. We reviewed patients with symptomatic peripheral artery disease who underwent peripheral angiography and/or endovascular intervention from 2006 to 2013 who were not taking other lipid-lowering medications. HI statin use was defined as atorvastatin 40-80 mg or rosuvastatin 20-40 mg. Baseline demographics, procedural data, and outcomes were retrospectively analyzed. Among 909 patients, 629 (69%) were prescribed statins, and 124 (13.6%) were treated with HI statin therapy. Mean low-density lipoprotein level was similar in patients on LMI versus HI (80±30 versus 87±44 mg/dL, P =0.14). Demographics including age (68±12 versus 67±10 years, P =0.25), smoking history (76% versus 80%, P =0.42), diabetes mellitus (54% versus 48%, P =0.17), and hypertension (88% versus 89%, P =0.78) were similar between groups (LMI versus HI). There was a higher prevalence of coronary artery disease (56% versus 75%, P =0.0001) among patients on HI statin (versus LMI). After propensity weighting, HI statin therapy was associated with improved survival (hazard ratio for mortality: 0.52; 95% confidence interval, 0.33-0.81; P =0.004) and decreased major adverse cardiovascular events (hazard ratio: 0.58; 95% confidence interval 0.37-0.92, P =0.02). In patients with peripheral artery disease who were referred for peripheral angiography or endovascular intervention, HI statin therapy was associated with improved survival and fewer major adverse cardiovascular events compared with LMI statin therapy. © 2017 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley.

  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. 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

    In situ saphenous vein arterial bypass flow was studied in 16 patients with respect to level of epidural anaesthesia. Arterial pressure and electromagnetic flow were used to evaluate arterial tone by intra-arterial (i.a.) papaverine. Eight patients had a low epidural block (... 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...... during low epidural anaesthesia (P i.a. papaverine was not significantly different in patients operated in low epidural and general anaesthesia (n = 8). In eight patients with insulin-dependent diabetes mellitus who had low epidural anaesthesia, the increase...

  6. Randomized trial of low versus high carbon dioxide insufflation pressures in posterior retroperitoneoscopic adrenalectomy.

    Science.gov (United States)

    Fraser, Sheila; Norlén, Olov; Bender, Kyle; Davidson, Joanne; Bajenov, Sonya; Fahey, David; Li, Shawn; Sidhu, Stan; Sywak, Mark

    2018-05-01

    Posterior retroperitoneoscopic adrenalectomy has gained widespread acceptance for the removal of benign adrenal tumors. Higher insufflation pressures using carbon dioxide (CO 2 ) are required, although the ideal starting pressure is unclear. This prospective, randomized, single-blinded, study aims to compare physiologic differences with 2 different CO 2 insufflation pressures during posterior retroperitoneoscopic adrenalectomy. Participants were randomly assigned to a starting insufflation pressure of 20 mm Hg (low pressure) or 25 mm Hg (high pressure). The primary outcome measure was partial pressure of arterial CO 2 at 60 minutes. Secondary outcomes included end-tidal CO 2 , arterial pH, blood pressure, and peak airway pressure. Breaches of protocol to change insufflation pressure were permitted if required and were recorded. A prospective randomized trial including 31 patients (low pressure: n = 16; high pressure: n = 15) was undertaken. At 60 minutes, the high pressure group had greater mean partial pressure of arterial CO 2 (64 vs 50 mm Hg, P = .003) and end-tidal CO 2 (54 vs 45 mm Hg, P = .008) and a lesser pH (7.21 vs 7.29, P = .0005). There were no significant differences in base excess, peak airway pressure, operative time, or duration of hospital stay. Clinically indicated protocol breaches were more common in the low pressure than the high pressure group (8 vs 3, P = .03). In posterior retroperitoneoscopic adrenalectomy, greater insufflation pressures are associated with greater partial pressure of arterial CO 2 and end-tidal CO 2 and lesser pH at 60 minutes, be significant. Commencing with lesser CO 2 insufflation pressures decreases intraoperative acidosis. Copyright © 2017 Elsevier Inc. All rights reserved.

  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. 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.

  9. Carbon in high-purity germanium

    International Nuclear Information System (INIS)

    Haller, E.E.; Hansen, W.L.; Luke, P.; McMurray, R.; Jarrett, B.

    1981-10-01

    Using 14 C-spiked pyrolytic graphite-coated quartz crucibles for the growth of nine ultra-pure germanium single crystals, we have determined the carbon content and distribution in these crystals. Using autoradiography, we observe a rapidly decreasing carbon cluster concentration in successively grown crystals. Nuclear radiation detectors made from the crystals measure the betas from the internally decaying 14 C nuclei with close to 100% efficiency. An average value for the total carbon concentration [ 14 C + 12 C] is approx. 2 x 10 14 cm -3 , a value substantially larger than expected from earlier metallurgical studies. Contrary to the most recent measurement, we find the shape of the beta spectrum to agree very well with the statistical shape predicted for allowed transitions

  10. 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.

  11. Carbon nanotubes for high-performance logic

    NARCIS (Netherlands)

    Chen, Zhihong; Philip Wong, H.-S.; Mitra, S.; Bol, A.A.; Peng, Lianmao; Hills, Gage; Thissen, N.F.W.

    2014-01-01

    Single-wall carbon nanotubes (CNTs) were discovered in 1993 and have been an area of intense research since then. They offer the right dimensions to explore material science and physical chemistry at the nanoscale and are the perfect system to study low-dimensional physics and transport. In the past

  12. High performance carbon–carbon composites

    Indian Academy of Sciences (India)

    R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

    protected against oxidation either through matrix modification with Si, Zr, Hf etc. or by multilayer oxidation protection ... advanced composites for a wide range of applications. The majority of products still ... CVD is a very slow process and it takes months together to get dense carbon–carbon composites. Porous structures ...

  13. New technology for carbon dioxide at high pressure

    International Nuclear Information System (INIS)

    Hassina, Bazaze; Raouf, Zehioua; Menial, A. H.

    2006-01-01

    Carbon dioxide has long been the nemesis of environmentalists because of its role in global warming, but under just the right conditions-namely, high pressure and high temperature its one of nature's best and most environmentally benign solvents. Decaf-coffee lovers, for instance, benefit from its ability to remove caffeine from coffee beans.During the last few years, carbon dioxide has also made inroads in the dry-cleaning industry, providing a safe cleaning alternative to the chemical perchloroethylene. But it's on the high-tech front that carbon dioxide may make its biggest impact. T here are huge opportunities. Scientists have known for more than a century that at 75 times atmospheric pressure and 31 degree centigrade, carbon dioxide goes into and odd state that chemists called s upercritical . What's interesting to industry is that supercritical carbon dioxide may be an enabling technology for going to smaller dimensions.(Author)

  14. 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.

  15. Feasibility of recanalization of human coronary arteries using high-intensity ultrasound.

    Science.gov (United States)

    Ernst, A; Schenk, E A; Woodlock, T J; Alliger, H; Gottlieb, S; Child, S Z; Meltzer, R S

    1994-01-15

    To investigate the feasibility of ultrasonic recanalization of obstructed human coronary arteries in vitro, high-intensity ultrasound was applied to 16 coronary arteries obtained at autopsy, using a prototype instrument enabling insonification through a catheter tip. It was a 119 cm long, 0.95 mm thick wire in an 8Fr catheter connected to an external ultrasonic transformer and power generator. A 5 MHz phased-array 2-dimensional echocardiography instrument was used to determine minimal luminal diameter and percent diameter narrowing before and after ultrasound application. The ultrasonic energy was delivered at 21.5 kHz and with a 52 +/- 19 micrometer average amplitude of tip displacement. The mean percent luminal diameter narrowing, flow rate and mean pressure gradient before ultrasound exposure were 74 +/- 11%, 97 +/- 61 ml/min, and 92 +/- 18 mm Hg, respectively. After recanalization, the mean percent luminal diameter narrowing decreased to 45 +/- 17% (p ultrasound application. Mechanical fracture of the wire occurred in 8 cases (50%). No signs of thermal injury were found on histology. Thus, ultrasonic recanalization of human coronary arteries in vitro is feasible. It may reduce obstruction and improve blood flow. Debris sizes are sufficiently small to minimize the hazard of peripheral embolization.

  16. High-dose external beam irradiation inhibits neointima formation in stented pig coronary arteries

    International Nuclear Information System (INIS)

    Verheye, Stefan; Coussement, Patrick K.; Salame, Mahomed Y.; Fallahi, Payam; Cui Jianhua; Chronos, Nicolas A.F.; King, Spencer B.; Crocker, Ian R.; Robinson, Keith A.

    2001-01-01

    Purpose: To evaluate high-dose external beam irradiation (EBRT) in a pig coronary stent preparation because low and intermediate-dose EBRT failed to show inhibition of neointima formation in stented animal models. Methods and Materials: Thirty-five stents were implanted in the coronary arteries of 17 pigs. Seven pigs were exposed to a single dose of 21 Gy EBRT immediately after stenting. Ten stented, nonirradiated pigs served as controls. After 4 weeks, the study arteries and myocardium were examined by light and scanning electron microscopy. Results: Compared with controls, 21 Gy EBRT resulted in a larger lumen area (7.57±1.67 mm 2 vs. 4.00±1.63 mm 2 , p 2 vs. 3.36±2.26 mm 2 , p<0.001) and a smaller maximal intimal thickness (0.16±0.09 mm vs. 0.68±0.31 mm, p<0.001). Unresorbed intramural hemorrhages and adherent mural thrombi were present in the irradiated vessels, which also showed incomplete re-endothelialization. The irradiated hearts demonstrated diffuse interstitial and perivascular inflammation and fibrosis. Conclusions: EBRT at 21 Gy to the entire heart significantly inhibited neointima formation in stented pig coronary arteries but also resulted in incomplete re-endothelialization, myocardial inflammation, and fibrosis. Improvements in localization and delivery techniques are required to allow clinical implementation of this technique

  17. Carbon-carbon composite and copper-composite bond damages for high flux component controlled fusion

    International Nuclear Information System (INIS)

    Chevet, G.

    2010-01-01

    Plasma facing components constitute the first wall in contact with plasma in fusion machines such as Tore Supra and ITER. These components have to sustain high heat flux and consequently elevated temperatures. They are made up of an armour material, the carbon-carbon composite, a heat sink structure material, the copper chromium zirconium, and a material, the OFHC copper, which is used as a compliant layer between the carbon-carbon composite and the copper chromium zirconium. Using different materials leads to the apparition of strong residual stresses during manufacturing, because of the thermal expansion mismatch between the materials, and compromises the lasting operation of fusion machines as damage which appeared during manufacturing may propagate. The objective of this study is to understand the damage mechanisms of the carbon-carbon composite and the composite-copper bond under solicitations that plasma facing components may suffer during their life. The mechanical behaviours of carbon-carbon composite and composite-copper bond were studied in order to define the most suitable models to describe these behaviours. With these models, thermomechanical calculations were performed on plasma facing components with the finite element code Cast3M. The manufacturing of the components induces high stresses which damage the carbon-carbon composite and the composite-copper bond. The damage propagates during the cooling down to room temperature and not under heat flux. Alternative geometries for the plasma facing components were studied to reduce damage. The relation between the damage of the carbon-carbon composite and its thermal conductivity was also demonstrated. (author) [fr

  18. Identification of Detrital Carbonate in East Cepu High

    Science.gov (United States)

    Sari, R.; Andika, I. K.; Haris, A.; Miftah, A.

    2018-03-01

    East Cepu High is a part of horst – graben series which formed by extensional tectonic processes during Paleogene in North East Java Basin. Due to excellent paleogeography position, the carbonate build-up was growth very well and as the main reservoir in East Cepu High. Sea level change have important factor to provide variation of facies in each carbonate buildup, one of emerging facies is detrital carbonate. Detrital carbonate indicated by onlap horizon featured with carbonate build up body. Based on paleogeography, fluctuation of sea level change and sediment source, detrital carbonate formed in leeward area in lowstand or highstand phases. Distinguish between detrital carbonate facies with other facies, advanced seismic processing performed by using continuous wavelet transform (CWT) and seismic inversion. CWT is one method of spectral decomposition used to find the frequency that represent a facies. The result from seismic inversion will support the interpretation for facies distribution. As the result, seismic data which have interval frequency 10 – 45 Hz and Acoustic Impedance (AI) value above 35000 (from cross plot between acoustic impedance and gamma ray) can be interpreted as detrital carbonate. Based on seismic interpretation, detrital carbonate facies distributed along leeward area with geometrical spreading. The lateral facies change from detrital carbonate to shale was identified which causing this facies become potential as hydrocarbon reservoir with stratigraphic trap. Based on the earlier studies, North East Java Basin have a strong hydrocarbon migration to fill the reservoir, therefore the detrital carbonate have high chance to be a new hydrocarbon prospect in this area.

  19. Comparison of high-resolution contrast-enhanced 3D MRA with digital subtraction angiography in the evaluation of hepatic arterial anatomy

    International Nuclear Information System (INIS)

    Matoba, M.; Tonami, H.; Kuginuki, M.; Yokota, H.; Takashima, S.; Yamamoto, I.

    2003-01-01

    AIM: To evaluate the validity of high-resolution contrast-enhanced three-dimensional magnetic resonance angiography (MRA) in defining hepatic arterial anatomy and to compare this with digital subtraction angiography (DSA). MATERIALS AND METHODS: MRA and DSA were performed in 30 patients. MRA was performed with breath-hold, gadolinium-enhanced, three-dimensional, fast low-angle shot sequence with a 512 pixel matrix. MRA was compared with DSA in terms of image quality and depiction of hepatic arterial anatomy. The agreement in image quality between MRA and DSA was determined with the kappa statistic. RESULTS: With respect to image quality, there was excellent or good correlation between MRA and DSA for the common hepatic artery (κ=0.85), proper hepatic artery (κ=0.72), gastroduodenal artery (κ=0.70), left hepatic artery (κ=0.49), left gastric artery (κ=0.50), splenic artery (κ=0.84), and superior mesenteric artery (κ=0.88). Poor correlation was found for the right hepatic artery (κ=0.18) and right gastric artery (κ=0.38). With regard to hepatic arterial anatomy, MRA correlated correctly with DSA in 28 of the 29 cases, i.e. 97% of patients. CONCLUSION: MRA is a useful technique for the evaluation of the hepatic artery, and for the vast majority of patients, MRA can replace intra-arterial DSA

  20. Prognostic value of stress echocardiography in women with high (⩾80%) probability of coronary artery disease

    OpenAIRE

    Davar, J; Roberts, E; Coghlan, J; Evans, T; Lipkin, D

    2001-01-01

    OBJECTIVE—To assess the prognostic significance of stress echocardiography in women with a high probability of coronary artery disease (CAD).
SETTING—Secondary and tertiary cardiology unit at a university teaching hospital.
PARTICIPANTS—A total of 135 women (mean (SD) age 63 (9) years) with pre-test probability of CAD ⩾80% were selected from a database of patients investigated by treadmill or dobutamine stress echocardiography between 1995 and 1998.
MAIN OUTCOME MEASURES—Patients were followe...

  1. Endovascular Management of Infected Femoral Artery Pseudoaneurysms in High-Risk Patients: A Case Series

    Energy Technology Data Exchange (ETDEWEB)

    D’Oria, Mario, E-mail: mario.doria88@outlook.com; Sgorlon, Giada; Calvagna, Cristiano; Zamolo, Francesca; Chiarandini, Stefano; Adovasio, Roberto; Griselli, Filippo [University Hospital of Cattinara, Vascular and Endovascular Surgery Unit (Italy)

    2017-04-15

    We report our experience with the urgent treatment of two high-risk patients with infected femoral artery pseudoaneurysms (IFAPs) with the placement of a self-expandable covered stent (SECS). In both cases, there was no perioperative mortality and the aneurysm exclusion was successful without early or late stent thrombosis/stent fracture nor acute or chronic limb ischemia or limb loss. There was no recurrence of local or systemic infection during the follow-up period. Endovascular therapy represents a feasible treatment option for IFAPs in those patients for whom the risk of open surgical repair would be prohibitive, especially under urgent circumstances.

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

    Science.gov (United States)

    Pallavee, P; Samal, Sunita; Samal, Rupal

    2013-01-01

    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.

  3. Uncovering the Driving Factors of Carbon Emissions in an Investment Allocation Model of China’s High-Carbon and Low-Carbon Energy

    Directory of Open Access Journals (Sweden)

    Shumin Jiang

    2017-06-01

    Full Text Available In the view of long-term comprehensive development, the concept of low-carbon economy has long been a concern. In this paper, we build a pure energy-economic system and explore the exact influencing factors in the investment allocation of high-carbon and low-carbon energy with the purpose of mitigating carbon dioxide in the atmosphere. The dynamic analysis shows that the model that we built is applicable for the current market situation and the way we adjust the investments of high-carbon and low-carbon energy are conductive to carbon abatement in the atmosphere. On the basis of the stability analysis and numerical simulation, some strategies are given to decrease the carbon dioxide in the atmosphere. The results show that the social consumption and public consumption behavior are the most important factors responsible for the variation in the atmospheric carbon dioxide. The cleanliness of high carbon presents an obvious mitigating effect on carbon in the atmosphere and the effect of marginal profit of high-carbon energy is the weakest. In addition, enhancing marginal profit, return on investment and investment share of low-carbon energy are beneficial to reduce carbon dioxide in the atmosphere, while a return on investment of high-carbon energy increasing is the detriment of the carbon dioxide in the atmosphere. Finally, we provide carbon mitigation effort by considering both economic development and carbon abatement for policymakers to achieve a desirable emission-reduction effect.

  4. Percutaneous closure of patent arterial ducts in patients from high altitude: a sub-Saharan experience.

    Science.gov (United States)

    Tefera, Endale; Qureshi, Shakeel A; Bermudez-Cañete, Ramòn; Rubio, Lola

    2015-01-01

    At high altitude, patent arterial ducts tend to be larger and associated with pulmonary hypertension. Patent ductus arteriosus device closure in this background could be challenging. We report our experience with percutaneous closure of patent arterial ducts using a variety of devices in patients residing in a high altitude. This is a retrospective review of the case records of 145 patients (age 9 months-20 years, mean 5.6 ± 3.9 years, and weight 7-54 kg, mean 17.7 ± 9.4) with duct sizes ranging between 2 and 21 mm, (mean, 5.8 ± 2.7) who underwent percutaneous closure of patent arterial ducts. One hundred thirty-six (93.8%) of the patients were from a geographic area of 2100-2800 m above sea level. Successful device closure was achieved in 143 cases. It was difficult to achieve device stability in two patients with expansile ducts. Therefore, they were treated surgically. The devices used were various types of duct occluder devices in 131 patients, while atrial and ventricular septal occluders were used in eight patients. For the group, mean systolic pulmonary artery (PA) pressure decreased from 47.0 ± 16.7 mmHg before occlusion to 29.0 ± 7.4 mmHg after occlusion (P ≤ 0.001)., mean diastolic PA pressure from 25.0 ± 10.9 mmHg to 14.8 ± 6.0 mmHg and the average mean PA pressure decreased from 35.9 ± 13.5 mmHg to 21.1 ± 6.5 mmHg. Complications (4.8%) included device and coil embolization, bleeding, and pulse loss. On follow-up (mean duration of 36.1 ± 12.1 months, range 12-62 months), 137 patients were in functional class 1, 3 had residual shunt, 2 had device migration and one patient had persisting pulse loss. Successful duct closure was achieved in the vast majority of patients, even though the ducts were larger and significant number of them had pulmonary hypertension in this high altitude group. There was a relatively higher incidence of residual shunts and device migration in this series, generally due to the nonavailability of optimal device and

  5. Highly reversible lead-carbon battery anode with lead grafting on the carbon surface

    KAUST Repository

    Yin, Jian; Lin, Nan; Zhang, Wenli; Lin, Zheqi; Zhang, Ziqing; Wang, Yue; Shi, Jun; Bao, Jinpeng; Lin, Haibo

    2018-01-01

    A novel C/Pb composite has been successfully prepared by electroless plating to reduce the hydrogen evolution and achieve the high reversibility of the anode of lead-carbon battery (LCB). The deposited lead on the surface of C/Pb composite was found to be uniform and adherent to carbon surface. Because lead has been stuck on the surface of C/Pb composite, the embedded structure suppresses the hydrogen evolution of lead-carbon anode and strengthens the connection between carbon additive and sponge lead. Compared with the blank anode, the lead-carbon anode with C/Pb composite displays excellent charge–discharge reversibility, which is attributed to the good connection between carbon additives and lead that has been stuck on the surface of C/Pb composite during the preparation process. The addition of C/Pb composite maintains a solid anode structure with high specific surface area and power volume, and thereby, it plays a significant role in the highly reversible lead-carbon anode.

  6. Highly reversible lead-carbon battery anode with lead grafting on the carbon surface

    KAUST Repository

    Yin, Jian

    2018-03-27

    A novel C/Pb composite has been successfully prepared by electroless plating to reduce the hydrogen evolution and achieve the high reversibility of the anode of lead-carbon battery (LCB). The deposited lead on the surface of C/Pb composite was found to be uniform and adherent to carbon surface. Because lead has been stuck on the surface of C/Pb composite, the embedded structure suppresses the hydrogen evolution of lead-carbon anode and strengthens the connection between carbon additive and sponge lead. Compared with the blank anode, the lead-carbon anode with C/Pb composite displays excellent charge–discharge reversibility, which is attributed to the good connection between carbon additives and lead that has been stuck on the surface of C/Pb composite during the preparation process. The addition of C/Pb composite maintains a solid anode structure with high specific surface area and power volume, and thereby, it plays a significant role in the highly reversible lead-carbon anode.

  7. Highly Enhanced Raman Scattering on Carbonized Polymer Films.

    Science.gov (United States)

    Yoon, Jong-Chul; Hwang, Jongha; Thiyagarajan, Pradheep; Ruoff, Rodney S; Jang, Ji-Hyun

    2017-06-28

    We have discovered a carbonized polymer film to be a reliable and durable carbon-based substrate for carbon enhanced Raman scattering (CERS). Commercially available SU8 was spin coated and carbonized (c-SU8) to yield a film optimized to have a favorable Fermi level position for efficient charge transfer, which results in a significant Raman scattering enhancement under mild measurement conditions. A highly sensitive CERS (detection limit of 10 -8 M) that was uniform over a large area was achieved on a patterned c-SU8 film and the Raman signal intensity has remained constant for 2 years. This approach works not only for the CMOS-compatible c-SU8 film but for any carbonized film with the correct composition and Fermi level, as demonstrated with carbonized-PVA (poly(vinyl alcohol)) and carbonized-PVP (polyvinylpyrollidone) films. Our study certainly expands the rather narrow range of Raman-active material platforms to include robust carbon-based films readily obtained from polymer precursors. As it uses broadly applicable and cheap polymers, it could offer great advantages in the development of practical devices for chemical/bio analysis and sensors.

  8. High power and high energy electrodes using carbon nanotubes

    Science.gov (United States)

    Martini, Fabrizio; Brambilla, Nicolo Michele; Signorelli, Riccardo

    2015-04-07

    An electrode useful in an energy storage system, such as a capacitor, includes an electrode that includes at least one to a plurality of layers of compressed carbon nanotube aggregate. Methods of fabrication are provided. The resulting electrode exhibits superior electrical performance in terms of gravimetric and volumetric power density.

  9. 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.

  10. Hierarchically structured nanoporous carbon tubes for high pressure carbon dioxide adsorption

    Directory of Open Access Journals (Sweden)

    Julia Patzsch

    2017-05-01

    Full Text Available Mesoscopic, nanoporous carbon tubes were synthesized by a combination of the Stoeber process and the use of electrospun macrosized polystyrene fibres as structure directing templates. The obtained carbon tubes have a macroporous nature characterized by a thick wall structure and a high specific surface area of approximately 500 m²/g resulting from their micro- and mesopores. The micropore regime of the carbon tubes is composed of turbostratic graphitic areas observed in the microstructure. The employed templating process was also used for the synthesis of silicon carbide tubes. The characterization of all porous materials was performed by nitrogen adsorption at 77 K, Raman spectroscopy, infrared spectroscopy, thermal gravimetric analysis (TGA, scanning electron microscopy (SEM as well as transmission electron microscopy (TEM. The adsorption of carbon dioxide on the carbon tubes at 25 °C at pressures of up to 30 bar was studied using a volumetric method. At 26 bar, an adsorption capacity of 4.9 mmol/g was observed. This is comparable to the adsorption capacity of molecular sieves and vertically aligned carbon nanotubes. The high pressure adsorption process of CO2 was found to irreversibly change the microporous structure of the carbon tubes.

  11. Highly Crumpled All-Carbon Transistors for Brain Activity Recording.

    Science.gov (United States)

    Yang, Long; Zhao, Yan; Xu, Wenjing; Shi, Enzheng; Wei, Wenjing; Li, Xinming; Cao, Anyuan; Cao, Yanping; Fang, Ying

    2017-01-11

    Neural probes based on graphene field-effect transistors have been demonstrated. Yet, the minimum detectable signal of graphene transistor-based probes is inversely proportional to the square root of the active graphene area. This fundamentally limits the scaling of graphene transistor-based neural probes for improved spatial resolution in brain activity recording. Here, we address this challenge using highly crumpled all-carbon transistors formed by compressing down to 16% of its initial area. All-carbon transistors, chemically synthesized by seamless integration of graphene channels and hybrid graphene/carbon nanotube electrodes, maintained structural integrity and stable electronic properties under large mechanical deformation, whereas stress-induced cracking and junction failure occurred in conventional graphene/metal transistors. Flexible, highly crumpled all-carbon transistors were further verified for in vivo recording of brain activity in rats. These results highlight the importance of advanced material and device design concepts to make improvements in neuroelectronics.

  12. 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.

  13. High-Resolution 3 T MR Microscopy Imaging of Arterial Walls

    International Nuclear Information System (INIS)

    Sailer, Johannes; Rand, Thomas; Berg, Andreas; Sulzbacher, Irene; Peloschek, P.; Hoelzenbein, Thomas; Lammer, Johannes

    2006-01-01

    Purpose. To achieve a high spatial resolution in MR imaging that allows for clear visualization of anatomy and even histology and documentation of plaque morphology in in vitro samples from patients with advanced atherosclerosis. A further objective of our study was to evaluate whether T2-weighted high-resolution MR imaging can provide accurate classification of atherosclerotic plaque according to a modified American Heart Association classification. Methods. T2-weighted images of arteries were obtained in 13 in vitro specimens using a 3 T MR unit (Medspec 300 Avance/Bruker, Ettlingen, Germany) combined with a dedicated MR microscopy system. Measurement parameters were: T2-weighted sequences with TR 3.5 sec, TE 15-120 msec; field of view (FOV) 1.4 x 1.4; NEX 8; matrix 192; and slice thickness 600 μm. MR measurements were compared with corresponding histologic sections. Results. We achieved excellent spatial and contrast resolution in all specimens. We found high agreement between MR images and histology with regard to the morphology and extent of intimal proliferations in all but 2 specimens. We could differentiate fibrous caps and calcifications from lipid plaque components based on differences in signal intensity in order to differentiate hard and soft atheromatous plaques. Hard plaques with predominantly intimal calcifications were found in 7 specimens, and soft plaques with a cholesterol/lipid content in 5 cases. In all specimens, hemorrhage or thrombus formation, and fibrotic and hyalinized tissue could be detected on both MR imaging and histopathology. Conclusion. High-resolution, high-field MR imaging of arterial walls demonstrates the morphologic features, volume, and extent of intimal proliferations with high spatial and contrast resolution in in vitro specimens and can differentiate hard and soft plaques

  14. 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

  15. 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.

  16. 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

  17. 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.

  18. Inhibition of ROS and inflammation by an imidazopyridine derivative X22 attenuate high fat diet-induced arterial injuries.

    Science.gov (United States)

    Li, Weixin; Wang, Lintao; Huang, Weijian; Skibba, Melissa; Fang, Qilu; Xie, Longteng; Wei, Tiemin; Feng, Zhiguo; Liang, Guang

    2015-09-01

    Obesity is strongly associated with the cause of structural and functional changes of the artery. Oxidative stress and inflammation play a critical role in the development of obesity-induced cardiovascular disorders. Our group previously found that an imidazopyridine derivative X22 showed excellent anti-inflammatory activity in LPS-stimulated macrophages. This study was designed to investigate the protective effects of X22 on high fat diet (HFD)-induced arterial injury and its underlying mechanisms. We observed that palmitate (PA) treatment in HUVECs induced a marked increase in reactive oxygen species, inflammation, apoptosis, and fibrosis. All of these changes were effectively suppressed by X22 treatment in a dose-dependent manner, associated with NF-κB inactivation and Nrf-2 activation. In HFD-fed rats, administration of X22 at 10mg/kg significantly decreased the arterial inflammation and oxidative stress, and eventually improved the arterial matrix remodeling and apoptosis. X22 at 10mg/kg showed a comparable bioactivity with the positive control, curcumin at 50mg/kg. The in vivo beneficial effects of X22 are also associated with its ability to increase Nrf2 expression and inhibit NF-κB activation in the artery of HFD-fed rats. Overall, these results suggest that X22 may have therapeutic potential in the treatment of obesity-induced artery injury via regulation of Nrf2-mediated oxidative stress and NF-κB-mediated inflammation. Copyright © 2015 Elsevier Inc. All rights reserved.

  19. EFFECT OF ASCORBIC ACID ON THE RIGHT AND LEFT CORONARY ARTERIES OF MALE RABBITS FED WITH HIGH-CHOLESTEROL DIET

    Directory of Open Access Journals (Sweden)

    Gholamreza Dashti

    2010-12-01

    Full Text Available   Abstract INTRODUCTION: Atherosclerosis and cardiovascular diseases are the most common causes of death in western countries. The beneficial effect of ascorbic acid on various organs has been reported. The present study was conducted to determine the effect of ascorbic acid on the right and left coronary arteries of male rabbits fed with high-cholesterol diet. methods: Twenty white male rabbits (mean weight: 950 g were weighed and randomly divided into two groups. For 40 days, group 1 (n=10 was given a high-cholesterol (1% diet, group 2 (n=10 was fed with a high-cholesterol diet and ascorbic acid (100 mg/kg. Then both of the groups were weighed and the animals were sacrificed. The right and left coronary arteries were dissected and then fixation, tissue processing, histological sectioning and H & E staining were carried out and sections were studied by light microscopy. The results were analyzed by using the Mann Whitney test. results: Group 2 which received ascorbic acid had no fatty streaks in their coronary arteries. Significant difference in mean weight was observed before and after the diet in both groups (P<0.05. CONCLUSIONS: Histopathological study of the coronary arteries showed that the rabbits which received ascorbic acid diet did not develop fatty streaks. Thus ascorbic acid exerts an apparently inhibitory effect on fatty streak formation and may slow down or prevent atherosclerosis by countering the side effects of a high-fat meal.     Keywords: Ascorbic acid, cholesterol, coronary arteries.

  20. 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

  1. 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. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Confinement of hydrogen at high pressure in carbon nanotubes

    Science.gov (United States)

    Lassila, David H [Aptos, CA; Bonner, Brian P [Livermore, CA

    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.

  3. A Comparison of Po2, Pco2, Ph and Bicarbonate in Blood from the Carotid and Coccygeal Arteries of Calves

    OpenAIRE

    Gustin, Pascal; de Groote, A.; Dhem, A. R.; Bakima, M.; Lomba; Lekeux, Pierre

    1988-01-01

    A technique is described for the subcutaneous deviation of the carotid artery into the jugular groove of calves weighing between 90 and 200 kg. This makes sampling arterial blood or chronic cannulation for further experimentation very easy. Values of oxygen tension, carbon dioxide tension, pH and bicarbonate concentration in blood sampled from the ventral coccygeal artery were compared with the values obtained in blood from carotid artery puncture. The high correlations observed indicate that...

  4. Usefulness of computed tomography angiography for the detection of high-risk aortas for carotid artery stenting

    International Nuclear Information System (INIS)

    Yamamoto, Hiromichi; Kuwayama, Naoya; Hayashi, Nakamasa; Kubo, Michiya; Endo, Shunro

    2011-01-01

    This study evaluated the usefulness of computed tomography (CT) angiography for the detection of high-risk aortas for carotid artery stenting (CAS). We investigated changes in the treatment method and modifications of endovascular techniques according to the information from CT angiography. CT angiography using three-dimensional and multi-planar reconstruction was performed in 43 consecutive patients with carotid artery stenoses intended to undergo CAS. Two neurosurgeons evaluated the images and estimated the risk and difficulties of CAS. CT angiography clearly depicted the entire aorta, the supra-aortic vessels, and the ilio-femoral arteries in all patients. Abnormal vascular findings were found in 17 patients. High-risk aortic lesions for CAS were detected in 5 patients, including thick aortic plaques with thrombi in 2. We changed the treatment strategy from CAS to carotid endarterectomy (CEA) in these 2 patients. CT angiograms proved very useful in evaluating the approach routes of CAS in 12 patients. One patient had dissecting aneurysm of the thoracic aorta and another had aberrant right vertebral artery. In these two, the treatment strategy was changed from CAS to CEA. The treatment method was changed in 4 patients in total. CT angiography is useful for the detection of high-risk aortas for CAS and for the evaluation of safe approaches to the carotid artery. (author)

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

    International Nuclear Information System (INIS)

    Negron M, A.; Ramos B, S.; Camargo R, C.; Uribe, R. M.; Gomez V, V.; Kobayashi, K.

    2014-08-01

    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)

  6. 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)

  7. 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 and to id......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...

  8. 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.

  9. MR angiography of the carotid arteries and intracranial circulation: advantage of a high relaxivity contrast agent

    International Nuclear Information System (INIS)

    Anzalone, N.; Scotti, R.; Iadanza, A.

    2006-01-01

    Several studies have shown the usefulness of contrast-enhanced MR angiography (CE-MRA) for imaging the supraortic vessels, and, as a consequence, it has rapidly become a routine imaging modality. The main advantage over unenhanced techniques is the possibility to acquire larger volumes, allowing demonstration of the carotid artery from its origin to the intracranial portion. Most published studies on CE-MRA of the carotid arteries have been performed with standard Gd-based chelates whose T1 relaxivity values are similar. Recently new gadolinium chelates such as gadobenate dimeglumine (Gd-BOP-TA, MultiHance; Bracco Imaging, Milan, Italy) have been developed which have markedly higher intravascular T1 relaxivity values. When administered at an equivalent dose to that of a standard agent, these newer contrast agents produce significantly greater intravascular signal enhancement. The availability of an appropriate high-relaxivity contrast agent might also help to overcome some of the intrinsic technical problems (e. g. those related to flow) that affect time-of-flight (TOF) and phase contrast (PC) MR angiography of the intracranial vasculature. To avoid the problem of superimposition of veins, ultrafast gradient echo MRA techniques with very short TR and TE have been developed. Although the precise sequence parameters vary between manufacturers, they are basically similar. The choice between performing a time-resolved or high spatial resolution CE-MRA examination depends upon the precise clinical application. The most common applications include the study of cerebral aneurysms, arteriovenous malformations, dural arteriovenous fistulas and dural venous diseases

  10. 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.

  11. 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

    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......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...... 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...

  12. Dynamic Contrast-Enhanced Perfusion MRI of High Grade Brain Gliomas Obtained with Arterial or Venous Waveform Input Function.

    Science.gov (United States)

    Filice, Silvano; Crisi, Girolamo

    2016-01-01

    The aim of this study was to evaluate the differences in dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) perfusion estimates of high-grade brain gliomas (HGG) due to the use of an input function (IF) obtained respectively from arterial (AIF) and venous (VIF) approaches by two different commercially available software applications. This prospective study includes 20 patients with pathologically confirmed diagnosis of high-grade gliomas. The data source was processed by using two DCE dedicated commercial packages, both based on the extended Toft model, but the first customized to obtain input function from arterial measurement and the second from sagittal sinus sampling. The quantitative parametric perfusion maps estimated from the two software packages were compared by means of a region of interest (ROI) analysis. The resulting input functions from venous and arterial data were also compared. No significant difference has been found between the perfusion parameters obtained with the two different software packages (P-value < .05). The comparison of the VIFs and AIFs obtained by the two packages showed no statistical differences. Direct comparison of DCE-MRI measurements with IF generated by means of arterial or venous waveform led to no statistical difference in quantitative metrics for evaluating HGG. However, additional research involving DCE-MRI acquisition protocols and post-processing would be beneficial to further substantiate the effectiveness of venous approach as the IF method compared with arterial-based IF measurement. Copyright © 2015 by the American Society of Neuroimaging.

  13. Bainite formation kinetics in high carbon alloyed steel

    International Nuclear Information System (INIS)

    Luzginova, N.V.; Zhao, L.; Sietsma, J.

    2008-01-01

    In recent years, many investigations have been carried out on the modeling of the bainite formation. In the present work, a physical approach proposed in the literature is implemented to model the formation of lower bainite in high carbon steels (1 wt.% C). In this model, the carbon diffusion is assumed to control the kinetics of the bainite formation. Both the nucleation and the growth rates are considered in an Avrami type analysis. The effect of alloying elements is taken into account considering only the thermodynamics of the system. The results and the physical meaning of the model parameters are discussed. It is shown that the diffusional approach gives a reasonable description of bainite formation kinetics in high carbon steel. Only two fitting parameters are used: the first accounts for carbon grain-boundary diffusion and the second is the initial nucleation-site density. The model satisfactorily accounts for the effect of transformation temperature, but does not take into account the carbide precipitation during bainite formation and the effect of alloying elements on the diffusion coefficient of carbon

  14. Uterine Artery Embolization for Symptomatic Fibroids with High Signal Intensity on T2-Weighted MR Imaging

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Suyon; Kim, Man Deuk; Lee, Myung Su; Lee, Mu Sook; Park, Sung Il; Won, Jong Yun; Lee, Do Yun; Lee, Kwang Hun [Dept. of Radiology, Research Institute of Radiological Science, Yonsei University College of Medicine, Severance Hospital, Seoul (Korea, Republic of)

    2012-09-15

    To evaluate the effectiveness of uterine artery embolization (UAE) for treating symptomatic fibroids with high signal intensity (SI) on magnetic resonance (MR) T2-weighted imaging (T2WI). A total of 537 cases, consisting of 14 patients with high SI fibroids on T2WI (T2 high group), were retrospectively included and compared with 28 randomly selected patients with low SI fibroids on T2WI (control group). High SI of a predominant fibroid on T2WI was defined as having the same or higher SI than the myometrium. Patient ages ranged from 28 to 52 years (mean, 38.1 years). All patients underwent MRI before and after UAE. Predominant fibroid and uterine volumes were calculated with MR images. Symptom status in terms of menorrhagia and dysmenorrhea was scored on a scale of 0-10, with 0 being no symptoms and 10 being the baseline, or initial symptoms. Of the patients in the T2 high group, 13 out of 14 (92.9%) patients demonstrated complete necrosis of the predominant fibroids. The mean volume reduction rates of the predominant fibroids in the T2 high group was 61.7% at three months after UAE, which was significantly higher than the volume reduction rates of 42.1% noted in the control group (p < 0.05). Changes in symptom scores for menorrhagia and dysmenorrhea after UAE (baseline score minus follow-up score) were 4.9 and 7.5 in T2 high group and they were 5.0 and 7.7 in control group, suggesting a significant resolution of symptoms (p < 0.01) in both groups but no significant difference between the two groups. UAE is effective for uttering fibroids showing high SI on T2WI. The mean volume reduction rate of the predominant fibroids three months after UAE was greater in the T2 high group than in the control group.

  15. Uterine Artery Embolization for Symptomatic Fibroids with High Signal Intensity on T2-Weighted MR Imaging

    International Nuclear Information System (INIS)

    Chang, Suyon; Kim, Man Deuk; Lee, Myung Su; Lee, Mu Sook; Park, Sung Il; Won, Jong Yun; Lee, Do Yun; Lee, Kwang Hun

    2012-01-01

    To evaluate the effectiveness of uterine artery embolization (UAE) for treating symptomatic fibroids with high signal intensity (SI) on magnetic resonance (MR) T2-weighted imaging (T2WI). A total of 537 cases, consisting of 14 patients with high SI fibroids on T2WI (T2 high group), were retrospectively included and compared with 28 randomly selected patients with low SI fibroids on T2WI (control group). High SI of a predominant fibroid on T2WI was defined as having the same or higher SI than the myometrium. Patient ages ranged from 28 to 52 years (mean, 38.1 years). All patients underwent MRI before and after UAE. Predominant fibroid and uterine volumes were calculated with MR images. Symptom status in terms of menorrhagia and dysmenorrhea was scored on a scale of 0-10, with 0 being no symptoms and 10 being the baseline, or initial symptoms. Of the patients in the T2 high group, 13 out of 14 (92.9%) patients demonstrated complete necrosis of the predominant fibroids. The mean volume reduction rates of the predominant fibroids in the T2 high group was 61.7% at three months after UAE, which was significantly higher than the volume reduction rates of 42.1% noted in the control group (p < 0.05). Changes in symptom scores for menorrhagia and dysmenorrhea after UAE (baseline score minus follow-up score) were 4.9 and 7.5 in T2 high group and they were 5.0 and 7.7 in control group, suggesting a significant resolution of symptoms (p < 0.01) in both groups but no significant difference between the two groups. UAE is effective for uttering fibroids showing high SI on T2WI. The mean volume reduction rate of the predominant fibroids three months after UAE was greater in the T2 high group than in the control group.

  16. SU-8 photoresist-derived electrospun carbon nanofibres as high ...

    Indian Academy of Sciences (India)

    2017-06-09

    Jun 9, 2017 ... as high-capacity anode material for lithium ion battery. M KAKUNURI, S KAUSHIK, A SAINI and C S SHARMA. ∗. Creative and Advanced Research Based On Nanomaterials (CARBON) Laboratory, Department of Chemical Engineering,. Indian Institute of Technology, Hyderabad, Kandi 502285, India. ∗.

  17. SU-8 photoresist-derived electrospun carbon nanofibres as high ...

    Indian Academy of Sciences (India)

    ... Refresher Courses · Symposia · Live Streaming. Home; Journals; Bulletin of Materials Science; Volume 40; Issue 3. SU-8 photoresist-derived electrospun carbon nanofibres as high-capacity anode material for lithium ion battery. M KAKUNURI S KAUSHIK A SAINI C S SHARMA. Volume 40 Issue 3 June 2017 pp 435-439 ...

  18. Cavitation-induced reactions in high-pressure carbon dioxide

    NARCIS (Netherlands)

    Kuijpers, M.W.A.; van Eck, D.; Kemmere, M.F.; Keurentjes, J.T.F.

    2002-01-01

    The feasibility of ultrasound-induced in situ radical formation in liquid carbon dioxide was demonstrated. The required threshold pressure for cavitation could be exceeded at a relatively low acoustic intensity, as the high vapor pressure of CO2 counteracts the hydrostatic pressure. With the use of

  19. High-performance carbon nanotube-reinforced bioplastic

    CSIR Research Space (South Africa)

    Ramontja, J

    2009-12-01

    Full Text Available -1 High-Performance Carbon Nanotube-Reinforced Bioplastic 1. James Ramontja1,2, 2. Suprakas Sinha Ray1,*, 3. Sreejarani K. Pillai1, 4. Adriaan S. Luyt2 1. 1 DST/CSIR Nanotechnology Innovation Centre, National Centre for Nano-Structured Materials...

  20. Venous-to-arterial carbon dioxide difference in the resuscitation of patients with severe sepsis and septic shock: A systematic review.

    Science.gov (United States)

    Diaztagle Fernández, J J; Rodríguez Murcia, J C; Sprockel Díaz, J J

    2017-10-01

    The way to assess tissue perfusion during the resuscitation of patients with severe sepsis and septic shock is a current subject of research and debate. Venous oxygen saturation and lactate concentration have been the most frequently used criteria, though they involve known limitations. The venous-to-arterial difference of carbon dioxide (pCO 2 delta) is a parameter than can be used to indicate tissue perfusion, and its determination therefore may be useful in these patients. A qualitative systematic review of the literature was made, comprising studies that assessed pCO 2 delta in adult patients with severe sepsis or septic shock, and published between January 1966 and November 2016 in the Medline-PubMed, Embase-Elsevier, Cochrane Library, and LILACS databases. There was no language restriction. The PRISMA statement was followed, and methodological quality was evaluated. Twelve articles were included, all of an observational nature, and including 10 prospective studies (9 published since 2010). Five documented greater mortality among patients with high pCO 2 delta values, in 3 cases even when achieving venous oxygen saturation targets. In 4 studies, a high pCO 2 delta was related to lower venous oxygen saturation and higher lactate levels, and another 3 documented lesser percentage lactate reductions. The parameter pCO 2 delta has been more frequently assessed in the management of patients with severe sepsis during the last few years. The studies demonstrate its correlation to mortality and other clinical outcomes, defining pCO 2 delta as a useful tool in the management of these patients. Copyright © 2017 Elsevier España, S.L.U. y SEMICYUC. All rights reserved.

  1. Optimal Treatment of the ‘High-Risk’ Patient with Carotid Artery Stenosis

    NARCIS (Netherlands)

    Fokkema, T.M.

    2013-01-01

    Four landmark randomized trials have clearly validated the use of carotid endarterectomy (CEA) for the management of asymptomatic and symptomatic significant carotid artery stenosis. However, its risk-to-benefit ratio is variable for different patients. With the advent of carotid artery stenting

  2. High-temperature carbonates in the Stillwater Complex, Montana, USA

    Science.gov (United States)

    Aird, H. M.; Boudreau, A. E.

    2012-12-01

    The processes involved in the petrogenesis of the sulphide-hosted platinum-group-element (PGE) deposits of the Stillwater Complex are controversial, with theories ranging from the purely magmatic to those involving an aqueous fluid. To further constrain these models, we have been examining the trace phase assemblages in rocks away from the ore zones. High-temperature carbonates have been observed in association with sulphide minerals below the platiniferous J-M Reef of the Stillwater Complex. The carbonate assemblage consists of dolomite with exsolved calcite and is found in contact with sulphide minerals: chalcopyrite and pyrrhotite in the Peridotite Zone; and pyrrhotite with pentlandite, pyrite and chalcopyrite in Gabbronorite I of the Lower Banded Series. The minimal silicate alteration and the lack of greenschist minerals in association with the mineral assemblage are consistent with a high-temperature origin for the carbonates. The calcite-dolomite geothermometer [1] yields a minimum formation temperature of ~900°C for the unmixed assemblages. A reaction rim surrounds the carbonate-sulphide assemblages, showing an alteration of the host orthopyroxene to a more Ca-enriched, Fe-depleted composition. This is consistent with diffusive exchange between carbonates and pyroxenes at high temperatures, mediated by an aqueous fluid. The highly variable molar MnO/FeO ratios in both the high-temperature carbonates and their associated altered pyroxene rims also imply their interaction with a fluid. The carbonate assemblages are consistent with Stillwater fluid inclusion studies [2], showing that fluids comprising coexisting Cl-rich brine and carbonic fluid were trapped in pegmatitic quartz at 700-715°C, some of which also contained "accidental" calcite inclusions. The high Cl-content of apatite [3] found below the platiniferous J-M Reef is further evidence that a Cl-rich fluid was migrating through the rocks beneath the Reef. Carbonates have been shown to be stabilized

  3. NOVEL CERAMIC MEMBRANE FOR HIGH TEMPERATURE CARBON DIOXIDE SEPARATION; SEMIANNUAL

    International Nuclear Information System (INIS)

    Jerry Y.S. Lin; Jun-ichi Ida

    2001-01-01

    This project is aimed at demonstrating technical feasibility for a lithium zirconate based dense ceramic membrane for separation of carbon dioxide from flue gas at high temperature. The research work conducted in this reporting period was focused on several fundamental issues of lithium zirconate important to the development of the dense inorganic membrane. These fundamental issues include material synthesis of lithium zirconate, phases and microstructure of lithium zirconate and structure change of lithium zirconate during sorption/desorption process. The results show difficulty to prepare the dense ceramic membrane from pure lithium zirconate, but indicate a possibility to prepare the dense inorganic membrane for carbon dioxide separation from a composite lithium zirconate

  4. Determination of vanadium in high grade carbons by radioanalytical methods

    International Nuclear Information System (INIS)

    Jinno, K.; Sato, M.; Amemiya, S.; Katoh, T.

    1980-01-01

    The present work deals with the determination of vanadium in high grade carbons by three radioanalytical methods, viz. thermal neutron activation analysis with an accelerator, thermal neutron activation analysis with a reactor and proton induced X-ray emission analysis with an accelerator. It is shown that thermal neutron activation with an accelerator is more convenient for the rapid and non-destructive analysis of ppm-level vanadium in bulk carbons than thermal neutron activation analysis with a reactor. Proton-induced X-ray emission is less useful for the analysis of bulk samples. (author)

  5. Carbonation by fluid-rock interactions at high-pressure conditions: Implications for carbon cycling in subduction zones

    Science.gov (United States)

    Piccoli, Francesca; Vitale Brovarone, Alberto; Beyssac, Olivier; Martinez, Isabelle; Ague, Jay J.; Chaduteau, Carine

    2016-07-01

    Carbonate-bearing lithologies are the main carbon carrier into subduction zones. Their evolution during metamorphism largely controls the fate of carbon, regulating its fluxes between shallow and deep reservoirs. Recent estimates predict that almost all subducted carbon is transferred into the crust and lithospheric mantle during subduction metamorphism via decarbonation and dissolution reactions at high-pressure conditions. Here we report the occurrence of eclogite-facies marbles associated with metasomatic systems in Alpine Corsica (France). The occurrence of these marbles along major fluid-conduits as well as textural, geochemical and isotopic data indicating fluid-mineral reactions are compelling evidence for the precipitation of these carbonate-rich assemblages from carbonic fluids during metamorphism. The discovery of metasomatic marbles brings new insights into the fate of carbonic fluids formed in subducting slabs. We infer that rock carbonation can occur at high-pressure conditions by either vein-injection or chemical replacement mechanisms. This indicates that carbonic fluids produced by decarbonation reactions and carbonate dissolution may not be directly transferred to the mantle wedge, but can interact with slab and mantle-forming rocks. Rock-carbonation by fluid-rock interactions may have an important impact on the residence time of carbon and oxygen in subduction zones and lithospheric mantle reservoirs as well as carbonate isotopic signatures in subduction zones. Furthermore, carbonation may modulate the emission of CO2 at volcanic arcs over geological time scales.

  6. 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.

  7. 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...

  8. Highly Efficient Catalytic Cyclic Carbonate Formation by Pyridyl Salicylimines.

    Science.gov (United States)

    Subramanian, Saravanan; Park, Joonho; Byun, Jeehye; Jung, Yousung; Yavuz, Cafer T

    2018-03-21

    Cyclic carbonates as industrial commodities offer a viable nonredox carbon dioxide fixation, and suitable heterogeneous catalysts are vital for their widespread implementation. Here, we report a highly efficient heterogeneous catalyst for CO 2 addition to epoxides based on a newly identified active catalytic pocket consisting of pyridine, imine, and phenol moieties. The polymeric, metal-free catalyst derived from this active site converts less-reactive styrene oxide under atmospheric pressure in quantitative yield and selectivity to the corresponding carbonate. The catalyst does not need additives, solvents, metals, or co-catalysts, can be reused at least 10 cycles without the loss of activity, and scaled up easily to a kilogram scale. Density functional theory calculations reveal that the nucleophilicity of pyridine base gets stronger due to the conjugated imines and H-bonding from phenol accelerates the reaction forward by stabilizing the intermediate.

  9. Carbon nanotubes as nanotexturing agents for high power supercapacitors based on seaweed carbons.

    Science.gov (United States)

    Raymundo-Piñero, Encarnación; Cadek, Martin; Wachtler, Mario; Béguin, François

    2011-07-18

    The advantages provided by multiwalled carbon nanotubes (CNTs) as backbones for composite supercapacitor electrodes are discussed. This paper particularly highlights the electrochemical properties of carbon composites obtained by pyrolysis of seaweed/CNTs blends. Due to the nanotexturing effect of CNTs, supercapacitors fabricated with electrodes from these composites exhibit enhanced electrochemical performances compared with CNT-free carbons. The cell resistance is dramatically reduced by the excellent conductivity of CNTs and by the good propagation of ions favored by the presence of opened mesopores. As a consequence, the specific power of supercapacitors based on these nanocomposites is very high. Another advantage related to the presence of CNTs is a better life cycle of the systems. The composite electrodes are resilient during the charge/discharge of capacitors; these are able to perfectly accommodate the dimensional changes appearing in the active material without mechanical damages. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. High-energy, short-pulse, carbon-dioxide lasers

    International Nuclear Information System (INIS)

    Fenstermacher, C.A.

    1979-01-01

    Lasers for fusion application represent a special class of short-pulse generators; not only must they generate extremely short temporal pulses of high quality, but they must do this at ultra-high powers and satisfy other stringent requirements by this application. This paper presents the status of the research and development of carbon-dioxide laser systems at the Los Alamos Scientific Laboratory, vis-a-vis the fusion requirements

  11. Performance of CVD and CVR coated carbon-carbon in high temperature hydrogen

    Science.gov (United States)

    Adams, J. W.; Barletta, R. E.; Svandrlik, J.; Vanier, P. E.

    As a part of the component development process for the particle bed reactor (PBR), it is necessary to develop coatings which will be time and temperature stable at extremely high temperatures in flowing hydrogen. These coatings must protect the underlying carbon structure from attack by the hydrogen coolant. Degradation which causes small changes in the reactor component, e.g. hole diameter in the hot frit, can have a profound effect on operation. The ability of a component to withstand repeated temperature cycles is also a coating development issue. Coatings which crack or spall under these conditions would be unacceptable. While refractory carbides appear to be the coating material of choice for carbon substrates being used in PBR components, the method of applying these coatings can have a large effect on their performance. Two deposition processes for these refractory carbides, chemical vapor deposition (CVD) and chemical vapor reaction (CVR), have been evaluated. Screening tests for these coatings consisted of testing of coated 2-D and 3-D weave carbon-carbon in flowing hot hydrogen at one atmosphere. Carbon loss from these samples was measured as a function of time. Exposure temperatures up to 3,000 K were used, and samples were exposed in a cyclical fashion cooling to room temperature between exposures. The results of these measurements are presented along with an evaluation of the relative merits of CVR and CVD coatings for this application.

  12. Efficacy of Novel Carbon Nanoparticle Antioxidant Therapy in a Severe Model of Reversible Middle Cerebral Artery Stroke in Acutely Hyperglycemic Rats

    Directory of Open Access Journals (Sweden)

    Roderic H. Fabian

    2018-04-01

    Full Text Available IntroductionWhile oxidative stress can be measured during transient cerebral ischemia, antioxidant therapies for ischemic stroke have been clinically unsuccessful. Many antioxidants are limited in their range and/or capacity for quenching radicals and can generate toxic intermediates overwhelming depleted endogenous protection. We developed a new antioxidant class, 40 nm × 2 nm carbon nanoparticles, hydrophilic carbon clusters, conjugated to poly(ethylene glycol termed PEG-HCCs. These particles are high-capacity superoxide dismutase mimics, are effective against hydroxyl radical, and restore the balance between nitric oxide and superoxide in the vasculature. Here, we report the effects of PEG-HCCs administered during reperfusion after transient middle cerebral artery occlusion (tMCAO by suture in the rat under hyperglycemic conditions. Hyperglycemia occurs in one-third of stroke patients and worsens clinical outcome. In animal models, this worsening occurs largely by accelerating elaboration of reactive oxygen species (ROS during reperfusion.MethodsPEG-HCCs were studied for their protective ability against hydrogen peroxide in b.End3 brain endothelial cell line and E17 primary cortical neuron cultures. In vivo, hyperglycemia was induced by streptozotocin injection 2 days before tMCAO. 58 Male Sprague-Dawley rats were analyzed. They were injected IV with PBS or PEG-HCCs (4 mg/kg 2× at the time of recanalization after either 90- or 120-min occlusion. Rats were survived for up to 3 days, and infarct volume characteristics and neurological functional outcome (modified Bederson Score were assessed.ResultsPEG-HCCs were protective against hydrogen peroxide in both culture models. In vivo improvement was found after PEG-HCCs with 90-min ischemia with reduction in infarct size (42%, hemisphere swelling (46%, hemorrhage score (53%, and improvement in Bederson score (70% (p = 0.068–0.001. Early high mortality in the 2-h in the PBS

  13. Carbon Dioxide Flush of an Integrated Minimized Perfusion Circuit Prior to Priming Prevents Spontaneous Air Release Into the Arterial Line During Clinical Use.

    Science.gov (United States)

    Stehouwer, Marco C; de Vroege, Roel; Hoohenkerk, Gerard J F; Hofman, Frederik N; Kelder, Johannes C; Buchner, Bas; de Mol, Bastian A; Bruins, Peter

    2017-11-01

    Recently, an oxygenator with an integrated centrifugal blood pump (IP) was designed to minimize priming volume and to reduce blood foreign surface contact even further. The use of this oxygenator with or without integrated arterial filter was compared with a conventional oxygenator and nonintegrated centrifugal pump. To compare the air removal characteristics 60 patients undergoing coronary artery bypass grafting were alternately assigned into one of three groups to be perfused with a minimized extracorporeal circuit either with the conventional oxygenator, the oxygenator with IP, or the oxygenator with IP plus integrated arterial filter (IAF). Air entering and leaving the three devices was measured accurately with a bubble counter during cardiopulmonary bypass. No significant differences between all groups were detected, considering air entering the devices. Our major finding was that in both integrated devices groups incidental spontaneous release of air into the arterial line in approximately 40% of the patients was observed. Here, detectable bolus air (>500 µm) was shown in the arterial line, whereas in the minimal extracorporeal circulation circuit (MECC) group this phenomenon was not present. We decided to conduct an amendment of the initial design with METC-approval. Ten patients were assigned to be perfused with an oxygenator with IP and IAF. Importantly, the integrated perfusion systems used in these patients were flushed with carbon dioxide (CO 2 ) prior to priming of the systems. In the group with CO 2 flush no spontaneous air release was observed in all cases and this was significantly different from the initial study with the group with the integrated device and IAF. This suggests that air spilling may be caused by residual air in the integrated device. In conclusion, integration of a blood pump may cause spontaneous release of large air bubbles (>500 µm) into the arterial line, despite the presence of an integrated arterial filter. CO 2 flushing of

  14. Highly selective and stable carbon dioxide uptake in polyindole-derived microporous carbon materials.

    Science.gov (United States)

    Saleh, Muhammad; Tiwari, Jitendra N; Kemp, K Christain; Yousuf, Muhammad; Kim, Kwang S

    2013-05-21

    Adsorption with solid sorbents is considered to be one of the most promising methods for the capture of carbon dioxide (CO₂) from power plant flue gases. In this study, microporous carbon materials used for CO₂ capture were synthesized by the chemical activation of polyindole nanofibers (PIF) at temperatures from 500 to 800 °C using KOH, which resulted in nitrogen (N)-doped carbon materials. The N-doped carbon materials were found to be microporous with an optimal adsorption pore size for CO₂ of 0.6 nm and a maximum (Brunauer-Emmett-Teller) BET surface area of 1185 m(2) g(-1). The PIF activated at 600 °C (PIF6) has a surface area of 527 m(2) g(-1) and a maximum CO₂ storage capacity of 3.2 mmol g(-1) at 25 °C and 1 bar. This high CO₂ uptake is attributed to its highly microporous character and optimum N content. Additionally, PIF6 material displays a high CO₂ uptake at low pressure (1.81 mmol g(-1) at 0.2 bar and 25 °C), which is the best low pressure CO₂ uptake reported for carbon-based materials. The adsorption capacity of this material remained remarkably stable even after 10 cycles. The isosteric heat of adsorption was calculated to be in the range of 42.7-24.1 kJ mol(-1). Besides the excellent CO₂ uptake and stability, PIF6 also exhibits high selectivity values for CO₂ over N₂, CH₄, and H₂ of 58.9, 12.3, and 101.1 at 25 °C, respectively, and these values are significantly higher than reported values.

  15. Denuded zone in Czochralski silicon wafer with high carbon content

    International Nuclear Information System (INIS)

    Chen Jiahe; Yang Deren; Ma Xiangyang; Que Duanlin

    2006-01-01

    The thermal stability of the denuded zone (DZ) created by high-low-high-temperature annealing in high carbon content (H[C]) and low carbon content (L[C]) Czochralski silicon (Cz-Si) has been investigated in a subsequent ramping and isothermal 1050 deg. C annealing. The tiny oxygen precipitates which might occur in the DZ were checked. It was found in the L[C] Cz-Si that the DZ shrank and the density of bulk micro-defects (BMDs) reduced with the increase of time spent at 1050 deg. C. Also, the DZs above 15 μm of thickness present in the H[C] Cz-Si wafers continuously and the density and total volume of BMDs first decreased then increased and finally decreased again during the treatments. Moreover, tiny oxygen precipitates were hardly generated inside the DZs, indicating that H[C] Cz-Si wafers could support the fabrication of integrated circuits

  16. Denuded zone in Czochralski silicon wafer with high carbon content

    Science.gov (United States)

    Chen, Jiahe; Yang, Deren; Ma, Xiangyang; Que, Duanlin

    2006-12-01

    The thermal stability of the denuded zone (DZ) created by high-low-high-temperature annealing in high carbon content (H[C]) and low carbon content (L[C]) Czochralski silicon (Cz-Si) has been investigated in a subsequent ramping and isothermal 1050 °C annealing. The tiny oxygen precipitates which might occur in the DZ were checked. It was found in the L[C] Cz-Si that the DZ shrank and the density of bulk micro-defects (BMDs) reduced with the increase of time spent at 1050 °C. Also, the DZs above 15 µm of thickness present in the H[C] Cz-Si wafers continuously and the density and total volume of BMDs first decreased then increased and finally decreased again during the treatments. Moreover, tiny oxygen precipitates were hardly generated inside the DZs, indicating that H[C] Cz-Si wafers could support the fabrication of integrated circuits.

  17. Highly Flexible Freestanding Porous Carbon Nanofibers for Electrodes Materials of High-Performance All-Carbon Supercapacitors.

    Science.gov (United States)

    Liu, Ying; Zhou, Jinyuan; Chen, Lulu; Zhang, Peng; Fu, Wenbin; Zhao, Hao; Ma, Yufang; Pan, Xiaojun; Zhang, Zhenxing; Han, Weihua; Xie, Erqing

    2015-10-28

    Highly flexible porous carbon nanofibers (P-CNFs) were fabricated by electrospining technique combining with metal ion-assistant acid corrosion process. The resultant fibers display high conductivity and outstanding mechanical flexibility, whereas little change in their resistance can be observed under repeatedly bending, even to 180°. Further results indicate that the improved flexibility of P-CNFs can be due to the high graphitization degree caused by Co ions. In view of electrode materials for high-performance supercapacitors, this type of porous nanostructure and high graphitization degree could synergistically facilitate the electrolyte ion diffusion and electron transportation. In the three electrodes testing system, the resultant P-CNFs electrodes can exhibit a specific capacitance of 104.5 F g(-1) (0.2 A g(-1)), high rate capability (remain 56.5% at 10 A g(-1)), and capacitance retention of ∼94% after 2000 cycles. Furthermore, the assembled symmetric supercapacitors showed a high flexibility and can deliver an energy density of 3.22 Wh kg(-1) at power density of 600 W kg(-1). This work might open a way to improve the mechanical properties of carbon fibers and suggests that this type of freestanding P-CNFs be used as effective electrode materials for flexible all-carbon supercapacitors.

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

    International Nuclear Information System (INIS)

    Ko, Heung Kyu; Shin, Ji Hoon; Ko, Gi Young; Gwon, Dong Il; Kim, Jin Hyung; Han, Ki Chang; Lee, Shin Wha

    2017-01-01

    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

  19. 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.

  20. Achieving high performance in intermediate temperature direct carbon fuel cells with renewable carbon as a fuel source

    International Nuclear Information System (INIS)

    Hao, Wenbin; He, Xiaojin; Mi, Yongli

    2014-01-01

    Highlights: • Bamboo fiber and waste paper were pyrolyzed to generate bamboo carbon and waste paper carbon as anode fuels of IT-DCFC. • Superior cell performance was achieved with the waste paper carbon. • The results suggested the high performance was due to the highest thermal reactivity and the catalytic inherent impurities. • Calcite and kaolinite as inherent impurities favored the thermal decomposition and the electrooxidation of carbon. - Abstract: Three kinds of carbon sources obtained from carbon black, bamboo fiber and waste paper were investigated as anode fuels in an intermediate temperature direct carbon fuel cell. The carbon sources were characterized with X-ray photoelectron spectroscopy, thermal gravimetric analysis, etc. The results indicated that the waste paper carbon was more abundant in calcite and kaolinite, and showed higher thermal reactivity in the intermediate temperature range compared with the other two carbon sources. The cell performance was tested at 650 °C in a hybrid single cell, using Sm 0.20 Ce 0.80 O 2−x as the electrolyte. As a result, the cell fed with waste paper carbon showed the highest performance among the three carbon sources, with a peak power density of 225 mW cm −2 . The results indicated that its inherent impurities, such as calcite and kaolinite, might favor the thermal gasification of renewable carbon sources, which resulted in the enhanced performance of the intermediate temperature direct carbon fuel cell

  1. High sodium intake during postnatal phases induces an increase in arterial blood pressure in adult rats.

    Science.gov (United States)

    Moreira, M C S; da Silva, E F; Silveira, L L; de Paiva, Y B; de Castro, C H; Freiria-Oliveira, A H; Rosa, D A; Ferreira, P M; Xavier, C H; Colombari, E; Pedrino, Gustavo R

    2014-12-28

    Epigenetic studies suggest that diseases that develop in adulthood are related to certain conditions to which the individual is exposed during the initial stages of life. Experimental evidence has demonstrated that offspring born to mothers maintained on high-Na diets during pregnancy have higher mean arterial pressure (MAP) in adulthood. Although these studies have demonstrated the importance of prenatal phases to hypertension development, no evidence regarding the role of high Na intake during postnatal phases in the development of this pathology has been reported. Therefore, in the present study, the effects of Na overload during childhood on induced water and Na intakes and on cardiovascular parameters in adulthood were evaluated. Experiments were carried out in two groups of 21-d-old rats: experimental group, maintained on hypertonic saline (0.3 m-NaCl) solution and food for 60 d, and control group, maintained on tap water and food. Later, both groups were given water and food for 15 d (recovery period). After the recovery period, chronic cannulation of the right femoral artery was performed in unanaesthetised rats to record baseline MAP and heart rate (HR). The experimental group was found to have increased basal MAP (98.6 (sem 2.6) v. 118.3 (sem 2.7) mmHg, P< 0.05) and HR (365.4 (sem 12.2) v. 398.2 (sem 7.5) beats per min, P< 0.05). There was a decrease in the baroreflex index in the experimental group when compared with that in the control group. A water and Na intake test was performed using furosemide. Na depletion was found to induce an increase in Na intake in both the control and experimental groups (12.1 (sem 0.6) ml and 7.8 (sem 1.1), respectively, P< 0.05); however, this increase was of lower magnitude in the experimental group. These results demonstrate that postnatal Na overload alters behavioural and cardiovascular regulation in adulthood.

  2. 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

  3. 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.

  4. Cardiac magnetic resonance imaging in patients with chest pain, high troponin levels and absence of coronary artery obstruction

    International Nuclear Information System (INIS)

    Avegliano, G.P.; Costabel, J.P.; Kuschnir, P.; Thierer, J.; Alves de Lima, A.; Sanchez, G.; Ronderos, J.; Huguet, M.; Petit, M.; Frangi, A.A.

    2011-01-01

    The prevalence of myocardial infarction with angiographically normal coronary arteries is approximately 7-10%. The etiological diagnosis is sometimes difficult and is important in terms of clinical practice and prognosis. The goal of our study was to show a series of consecutive patients with an initial diagnosis of acute coronary syndrome with high troponin levels and absence of coronary artery obstruction in which cardiac magnetic resonance imaging (CMRI) gave a description of the myocardial lesion, orientating towards the etiological diagnosis. From January 2005 to December 2009, 720 consecutive patients with an initial diagnosis of acute coronary syndrome and elevated troponins were included; 64 of these patients did not present angiographically significant coronary artery stenosis. Within 72 ± 24 h after coronary angiography, these patients underwent CMRI using b-SSFP sequences for cine imaging in short-axis, 2-, 3- and 4- chamber views for the evaluation of segmental wall motion, with T2-weighted and delayed enhancement (DE) images of the myocardium with an 'inversion-recovery' sequence. The following diagnoses were made: myocarditis (39 patients); myocardial infarction (12 patients); Tako-Tsubo syndrome (8 patients); apical hypertrophic cardiomyopathy (2 patients); 3 patients remained without diagnosis. These findings demonstrate the usefulness of CMRI in the clinical scenario of patients with chest pain, inconclusive ECG findings and high troponin levels with angiographically normal coronary arteries. The presence and distribution pattern of DE make it possible to define the etiological diagnosis and interpret the physiopathological process. (authors) [es

  5. High performance supercapacitor using catalysis free porous carbon nanoparticles

    International Nuclear Information System (INIS)

    Ali, Gomaa A M; Manaf, Shoriya Aruni Bt Abdul; Chong, Kwok Feng; Hegde, Gurumurthy; Kumar, Anuj

    2014-01-01

    Very high supercapacitance values are obtained using catalyst free porous carbon nanoparticles (PCNs). The obtained PCNs have a porous structure with fine particles 35 nm in size. The specific capacitance of PCNs is 343 F g −1 and 309 F g −1 at 5 mV s −1 and 0.06 A g −1 , respectively. PCNs shows a high cyclic stability of about 90% and high columbic efficiency of 95% over 2500 cycles at 1 A g −1 . Impedance spectra show low resistance of PCNs, supporting their suitability for supercapacitor electrode application. (paper)

  6. High Gradient Accelerating Structures for Carbon Therapy Linac

    Energy Technology Data Exchange (ETDEWEB)

    Kutsaev, Sergey; Agustsson, R.; Faillace, L.; Goel, A.; Mustapha, B.; Nassiri, A.; Ostroumov, P.; Plastun, A.; Savin, E.

    2016-05-01

    Carbon therapy is the most promising among techniques for cancer treatment, as it has demonstrated significant improvements in clinical efficiency and reduced toxicity profiles in multiple types of cancer through much better localization of dose to the tumor volume. RadiaBeam, in collaboration with Argonne National Laboratory, are developing an ultra-high gradient linear accelerator, Advanced Compact Carbon Ion Linac (ACCIL), for the delivery of ion-beams with end-energies up to 450 MeV/u for 12C6+ ions and 250 MeV for protons. In this paper, we present a thorough comparison of standing and travelling wave designs for high gradient S-Band accelerating structures operating with ions at varying velocities, relative to the speed of light, in the range 0.3-0.7. In this paper we will compare these types of accelerating structures in terms of RF, beam dynamics and thermo-mechanical performance.

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

    International Nuclear Information System (INIS)

    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 10 g cm -3 and if the propagation of the deflagration wave is slower than ∼ 0.15 υ/sub s/ (υ/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

  8. Thirty-day outcomes of direct carotid artery stenting with cerebral protection in high-risk patients

    International Nuclear Information System (INIS)

    Veselka, J.; Cerna, D.; Zimolova, P.; Blasko, P.; Fiedler, J.; Hajek, P.; Maly, M.; Zemanek, D.; Duchonova, R.

    2007-01-01

    Implantation of a carotid artery stent after predilation is a standard approach in the endovascular treatment of carotid artery stenoses. Stenting without predilation may be an alternative approach in a certain subset of patients. The present prospective, single-center registry was designed to evaluate the feasibility and safety of direct carotid artery stenting (DCAS) in high-risk patients. Symptomatic patients with stenosis >50% and asymptomatic patients with stenosis >70% were eligible for enrolment. Criteria for high-risk patients included: need or history of open heart surgery, history of myocardial infarction, multivessel coronary artery disease, left ventricular dysfunction (ejection fraction ≤40%), severe pulmonary or renal disease, significant contralateral carotid disease, previous endarterectomy, and age ≥80 years. All procedures were performed using a filter protection device. Patients underwent complete clinical examination before and after DCAS and at 30-day follow-up. A total of 83 consecutive patients (45 males, 68±9 years, 33% symptomatic) underwent 100 procedures and 103 stents were deployed successfully. The technical success rate of stenting was 100%. Predilation of carotid stenosis was necessary in 1 (1%) procedure. Carotid-artery stenoses before and after DCAS were 80±9% and 7±9%, respectively. The median fluoroscopic time for DCAS was 7 min. The overall rate of in-hospital major adverse cerebrovascular events (death, stroke, myocardial infarction) was 5% (2 minor strokes, 3 transient attacks). There was 1 (1%) minor stroke within the 30-day follow-up. DCAS is feasible and can be performed with an acceptable risk in high-risk patients. (author)

  9. Noninvasive Diagnosis of Coronary Artery Disease Using 12-Lead High-Frequency Electrocardiograms

    Science.gov (United States)

    Schlegel, Todd T.; Arenare, Brian

    2006-01-01

    A noninvasive, sensitive method of diagnosing certain pathological conditions of the human heart involves computational processing of digitized electrocardiographic (ECG) signals acquired from a patient at all 12 conventional ECG electrode positions. In the processing, attention is focused on low-amplitude, high-frequency components of those portions of the ECG signals known in the art as QRS complexes. The unique contribution of this method lies in the utilization of signal features and combinations of signal features from various combinations of electrode positions, not reported previously, that have been found to be helpful in diagnosing coronary artery disease and such related pathological conditions as myocardial ischemia, myocardial infarction, and congestive heart failure. The electronic hardware and software used to acquire the QRS complexes and perform some preliminary analyses of their high-frequency components were summarized in Real-Time, High-Frequency QRS Electrocardiograph (MSC- 23154), NASA Tech Briefs, Vol. 27, No. 7 (July 2003), pp. 26-28. To recapitulate, signals from standard electrocardiograph electrodes are preamplified, then digitized at a sampling rate of 1,000 Hz, then analyzed by the software that detects R waves and QRS complexes and analyzes them from several perspectives. The software includes provisions for averaging signals over multiple beats and for special-purpose nonrecursive digital filters with specific low- and high-frequency cutoffs. These filters, applied to the averaged signal, effect a band-pass operation in the frequency range from 150 to 250 Hz. The output of the bandpass filter is the desired high-frequency QRS signal. Further processing is then performed in real time to obtain the beat-to-beat root mean square (RMS) voltage amplitude of the filtered signal, certain variations of the RMS voltage, and such standard measures as the heart rate and R-R interval at any given time. A key signal feature analyzed in the present

  10. Pumpkin-Derived Porous Carbon for Supercapacitors with High Performance.

    Science.gov (United States)

    Bai, Suying; Tan, Guangqun; Li, Xiaoqin; Zhao, Qian; Meng, Yan; Wang, Yujue; Zhang, Yongzhi; Xiao, Dan

    2016-06-21

    Pumpkin has been employed for the first time as a renewable, low-cost precursor for the preparation of porous carbon materials with excellent performance. Unlike most other precursors, pumpkin is rich in sugars and starch, and it has advantageous properties for large-scale production. The as-prepared materials adopted a unique morphology that consisted of numerous fused sphere-like carbon grains with a high specific surface area (2968 m(2)  g(-1) ), abundant micro and mesopores, and excellent electrochemical properties. The pumpkin-derived activated carbon (PAC) material not only exhibited a high specific capacitance of 419 F g(-1) , but also showed considerable cycling stability, with 93.6 % retention after 10 000 cycles. Moreover, a symmetrical supercapacitor that was based on PAC showed a high energy density of 22.1 W h kg(-1) in aqueous electrolyte. These superior properties demonstrate that PAC holds great promise for applications in electrochemical energy-storage devices. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Diffusion barrier coatings for high temperature corrosion resistance of advanced carbon/carbon composites

    International Nuclear Information System (INIS)

    Singh Raman, K.S.

    2000-01-01

    Carbon possesses an excellent combination of mechanical and thermal properties, viz., excellent creep resistance at temperatures up to 2400 deg C in non-oxidizing environment and a low thermal expansion coefficient. These properties make carbon a potential material for very high temperature applications. However, the use of carbon materials at high temperatures is considerably restricted due to their extremely poor oxidation resistance at temperatures above 400 deg C. The obvious choice for improving high temperature oxidation resistance of such materials is a suitable diffusion barrier coating. This paper presents an overview of recent developments in advanced diffusion- and thermal-barrier coatings for ceramic composites, with particular reference to C/C composites. The paper discusses the development of multiphase and multi-component ceramic coatings, and recent investigations on the oxidation resistance of the coated C/C composites. The paper also discusses the cases of innovative engineering solutions for traditional problems with the ceramic coatings, and the scope of intelligent processing in developing coatings for the C/C composites. Copyright (2000) AD-TECH - International Foundation for the Advancement of Technology Ltd

  12. 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.

  13. 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

  14. European Registry of Carotid Artery Stenting: results from a prospective registry of eight high volume EUROPEAN institutions.

    Science.gov (United States)

    Stabile, Eugenio; Garg, Pallav; Cremonesi, Alberto; Bosiers, Marc; Reimers, Bernhard; Setacci, Carlo; Cao, Piergiorgio; Schmidt, Andrej; Sievert, Horst; Peeters, Patrick; Nikas, Dimitry; Werner, Martin; de Donato, Gianmarco; Parlani, Giambattista; Castriota, Fausto; Hornung, Marius; Mauri, Laura; Rubino, Paolo

    2012-08-01

    Carotid endarterectomy (CEA) is the standard revascularization therapy to prevent stroke in patients with carotid artery disease. Carotid artery stenting (CAS) could be considered a potential alternative in patients at high surgical risk. Recent clinical trials have challenged this concept due a relatively high incidence of post-CAS adverse events, which occurred in low volume centers. The aim of this study was to evaluate the outcomes associated with neuroprotected CAS in selected high volume centers. From January 2007 to December 2007, 1,611 patients underwent neuroprotected CAS in eight European Centers. For each patients, clinical, procedural, and one month follow-up data from all patients have been collected. An independent clinical events committee adjudicated the events. Overall in hospital death was 0.06% (one patient), whereas in-hospital stroke was 0.49% (eight patients). Between hospital discharge and 30 days three additional patients died (0.18%) and 10 patients experienced a stroke (0.67%). Overall 30 days mortality was 0.24% (four patients) and stroke incidence 1.12% (18 patients). The 30 day stroke/death rate was 1.36%. CAS is a reasonable alternative to CEA to treat carotid artery atherosclerosis in well-experienced high volume centers. These data suggest that future prospective trials comparing CAS and CEA outcomes should include only centers highly experienced in both treatment modalities. Copyright © 2012 Wiley Periodicals, Inc.

  15. Intravascular near-infrared fluorescence molecular imaging of atherosclerosis: toward coronary arterial visualization of biologically high-risk plaques

    Science.gov (United States)

    Calfon, Marcella A.; Vinegoni, Claudio; Ntziachristos, Vasilis; Jaffer, Farouc A.

    2010-01-01

    New imaging methods are urgently needed to identify high-risk atherosclerotic lesions prior to the onset of myocardial infarction, stroke, and ischemic limbs. Molecular imaging offers a new approach to visualize key biological features that characterize high-risk plaques associated with cardiovascular events. While substantial progress has been realized in clinical molecular imaging of plaques in larger arterial vessels (carotid, aorta, iliac), there remains a compelling, unmet need to develop molecular imaging strategies targeted to high-risk plaques in human coronary arteries. We present recent developments in intravascular near-IR fluorescence catheter-based strategies for in vivo detection of plaque inflammation in coronary-sized arteries. In particular, the biological, light transmission, imaging agent, and engineering principles that underlie a new intravascular near-IR fluorescence sensing method are discussed. Intravascular near-IR fluorescence catheters appear highly translatable to the cardiac catheterization laboratory, and thus may offer a new in vivo method to detect high-risk coronary plaques and to assess novel atherosclerosis biologics.

  16. Friction stir processing on high carbon steel U12

    Energy Technology Data Exchange (ETDEWEB)

    Tarasov, S. Yu., E-mail: tsy@ispms.ru; Rubtsov, V. E., E-mail: rvy@ispms.ru [Institute of Strength Physics and Materials Science SB RAS, Tomsk, 634055 (Russian Federation); National Research Tomsk Polytechnic University, Tomsk, 634050 (Russian Federation); Melnikov, A. G., E-mail: melnikov-ag@tpu.ru [National Research Tomsk Polytechnic University, Tomsk, 634050 (Russian Federation)

    2015-10-27

    Friction stir processing (FSP) of high carbon steel (U12) samples has been carried out using a milling machine and tools made of cemented tungsten carbide. The FSP tool has been made in the shape of 5×5×1.5 mm. The microstructural characterization of obtained stir zone and heat affected zone has been carried out. Microhardness at the level of 700 MPa has been obtained in the stir zone with microstructure consisting of large grains and cementitte network. This high-level of microhardness is explained by bainitic reaction developing from decarburization of austenitic grains during cementite network formation.

  17. On the carbide formation in high-carbon stainless steel

    International Nuclear Information System (INIS)

    Mujahid, M.; Qureshi, M.I.

    1996-01-01

    Stainless steels containing high Cr as well as carbon contents in excess of 1.5 weight percent have been developed for applications which require high resistance erosion and environmental corrosion. Formation of carbides is one of important parameters for controlling properties of these materials especially erosion characteristics. Percent work includes the study of different type of carbides which from during the heat treatment of these materials. It has been found that precipitation of secondary carbides and the nature of matrix transformation plays an important role in determining the hardness characteristics of these materials. (author)

  18. High-Performance Field Emission from a Carbonized Cork.

    Science.gov (United States)

    Lee, Jeong Seok; Lee, Hak Jun; Yoo, Jae Man; Kim, Taewoo; Kim, Yong Hyup

    2017-12-20

    To broaden the range of application of electron beams, low-power field emitters are needed that are miniature and light. Here, we introduce carbonized cork as a material for field emitters. The light natural cork becomes a graphitic honeycomb upon carbonization, with the honeycomb cell walls 100-200 nm thick and the aspect ratio larger than 100, providing an ideal structure for the field electron emission. Compared to nanocarbon field emitters, the cork emitter produces a high current density and long-term stability with a low turn-on field. The nature of the cork material makes it quite simple to fabricate the emitter. Furthermore, any desired shape of the emitter tailored for the final application can easily be prepared for point, line, or planar emission.

  19. 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.

  20. High performance all-carbon composite transparent electrodes containing uniform carbon nanotube networks

    Energy Technology Data Exchange (ETDEWEB)

    Yun, Hyung Duk; Kwak, Jinsung; Kim, Se-Yang [School of Materials Science and Engineering & Low-Dimensional Carbon Materials Center, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919 (Korea, Republic of); Seo, Han; Bang, In Cheol; Kim, Sung Youb [School of Mechanical and Nuclear Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919 (Korea, Republic of); Kang, Seoktae [Department of Civil and Environmental Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141 (Korea, Republic of); Kwon, Soon-Yong, E-mail: sykwon@unist.ac.kr [School of Materials Science and Engineering & Low-Dimensional Carbon Materials Center, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919 (Korea, Republic of); School of Mechanical and Nuclear Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919 (Korea, Republic of)

    2016-08-05

    Indium tin oxide-free, flexible transparent electrodes (TEs) are crucial for the future commercialization of flexible and wearable electronics. While carbon-based TEs containing carbon nanotube (CNT) networks show promise, they usually exhibit poor dispersion properties, limiting their performance and practicality. In this study, we report a highly efficient and bending durable all-carbon composite TE (ac-TE) that employs uniform CNT networks on a monolayer graphene/polyethylene terephthalate (PET) substrate via a simple air spray deposition method. The air-sprayed CNT/graphene assembly was free-standing on solution, making a polymer-free transfer of carbon composites to target substrates possible. The excellent performance of the ac-TEs was attributed to the uniformly networked CNTs on the polycrystalline graphene with a well-controlled density, effectively bridging the line defects and filling the tears/voids or folds necessarily existing in the as-processed graphene. The sheet resistance of the ac-TEs was increased only 6% from its original value at a bending radius of 2.7 mm, while that of the pristine graphene/PET assembly increased 237%. Mechanical bending of the ac-TEs worsened the electrical performance by only ∼1.7% after 2000 bending cycles at a bending radius of 2.5 mm. Degradation of the performance by the bending was the result of line defects formation in the graphene, demonstrating the potential of the uniform CNT networks to achieve more efficient and flexible carbon-based TEs. Furthermore, the chemically-doped ac-TEs showed commercially suitable electronic and optical properties with much enhanced thermal stability, closer to practical TEs in flexible devices. - Highlights: • Highly efficient and bending durable all-carbon composite transparent electrodes (TEs) are designed. • The performance was strongly dependent on morphology of CNT networks on graphene. • The mechanism relies on the defect reductions in graphene by uniform CNT coating

  1. High performance all-carbon composite transparent electrodes containing uniform carbon nanotube networks

    International Nuclear Information System (INIS)

    Yun, Hyung Duk; Kwak, Jinsung; Kim, Se-Yang; Seo, Han; Bang, In Cheol; Kim, Sung Youb; Kang, Seoktae; Kwon, Soon-Yong

    2016-01-01

    Indium tin oxide-free, flexible transparent electrodes (TEs) are crucial for the future commercialization of flexible and wearable electronics. While carbon-based TEs containing carbon nanotube (CNT) networks show promise, they usually exhibit poor dispersion properties, limiting their performance and practicality. In this study, we report a highly efficient and bending durable all-carbon composite TE (ac-TE) that employs uniform CNT networks on a monolayer graphene/polyethylene terephthalate (PET) substrate via a simple air spray deposition method. The air-sprayed CNT/graphene assembly was free-standing on solution, making a polymer-free transfer of carbon composites to target substrates possible. The excellent performance of the ac-TEs was attributed to the uniformly networked CNTs on the polycrystalline graphene with a well-controlled density, effectively bridging the line defects and filling the tears/voids or folds necessarily existing in the as-processed graphene. The sheet resistance of the ac-TEs was increased only 6% from its original value at a bending radius of 2.7 mm, while that of the pristine graphene/PET assembly increased 237%. Mechanical bending of the ac-TEs worsened the electrical performance by only ∼1.7% after 2000 bending cycles at a bending radius of 2.5 mm. Degradation of the performance by the bending was the result of line defects formation in the graphene, demonstrating the potential of the uniform CNT networks to achieve more efficient and flexible carbon-based TEs. Furthermore, the chemically-doped ac-TEs showed commercially suitable electronic and optical properties with much enhanced thermal stability, closer to practical TEs in flexible devices. - Highlights: • Highly efficient and bending durable all-carbon composite transparent electrodes (TEs) are designed. • The performance was strongly dependent on morphology of CNT networks on graphene. • The mechanism relies on the defect reductions in graphene by uniform CNT coating

  2. A high-performance mesoporous carbon supported nitrogen-doped carbon electrocatalyst for oxygen reduction reaction

    Science.gov (United States)

    Xu, Jingjing; Lu, Shiyao; Chen, Xu; Wang, Jianan; Zhang, Bo; Zhang, Xinyu; Xiao, Chunhui; Ding, Shujiang

    2017-12-01

    Investigating low-cost and highly active electrocatalysts for oxygen reduction reactions (ORR) is of crucial importance for energy conversion and storage devices. Herein, we design and prepare mesoporous carbon supported nitrogen-doped carbon by pyrolysis of polyaniline coated on CMK-3. This electrocatalyst exhibits excellent performance towards ORR in alkaline media. The optimized nitrogen-doped mesoporous electrocatalyst show an onset potential (E onset) of 0.95 V (versus reversible hydrogen electrode (RHE)) and half-wave potential (E 1/2) of 0.83 V (versus RHE) in 0.1 M KOH. Furthermore, the as-prepared catalyst presents superior durability and methanol tolerance compared to commercial Pt/C indicating its potential applications in fuel cells and metal-air batteries.

  3. 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.

  4. High Altitude Emissions of Black Carbon Aerosols: Potential Climate Implications

    Science.gov (United States)

    Satheesh, S. K.

    2017-12-01

    Synthesizing a series of ground-based and airborne measurements of aerosols over the Indian region during summer and pre-monsoon seasons have revealed the persistence of elevated absorbing aerosol layers over most of the Indian region; more than 50% of which located above clouds. Subsequent, in situ measurements of black carbon (BC) using high-altitude balloons, showed surprising layers with high concentrations in the middle and upper troposphere even at an altitude of 8 to 10 kms. Simultaneous measurements of the vertical thermal structure have shown localized warming due to BC absorption leading to large reduction in lapse rate and sharp temperature inversion, which in turn increases the atmospheric stability. This aerosol-induced stable layer is conducive for maintaining the black carbon layer longer at that level, leading thereby to further solar absorption and subsequently triggering dry convection. These observations support the `solar escalator' concept through which absorption-warming-convection cycles lead to self-lifting of BC to upper troposphere or even to lower stratosphere under favorable conditions in a matter of a few days. Employing an on-line regional chemistry transport model (WRF-Chem), incorporating aircraft emissions, it is shown that emissions from high-flying aircrafts as the most likely source of these elevated black carbon layers. These in-situ injected particles, produce significant warming of the thin air in those heights and lift these layers to even upper tropospheric/lower stratospheric heights, aided by the strong monsoonal convection occurring over the region, which are known to overshoot the tropical tropopause leading to injection of tropospheric air mass (along with its constituent aerosols) into the stratosphere, especially during monsoon season when the tropical tropopause layer is known to be thinnest. These simulations are further supported by the CALIPSO space-borne LIDAR derived extinction coefficient profiles. Based on

  5. High nitrogen-containing cotton derived 3D porous carbon frameworks for high-performance supercapacitors

    Science.gov (United States)

    Fan, Li-Zhen; Chen, Tian-Tian; Song, Wei-Li; Li, Xiaogang; Zhang, Shichao

    2015-10-01

    Supercapacitors fabricated by 3D porous carbon frameworks, such as graphene- and carbon nanotube (CNT)-based aerogels, have been highly attractive due to their various advantages. However, their high cost along with insufficient yield has inhibited their large-scale applications. Here we have demonstrated a facile and easily scalable approach for large-scale preparing novel 3D nitrogen-containing porous carbon frameworks using ultralow-cost commercial cotton. Electrochemical performance suggests that the optimal nitrogen-containing cotton-derived carbon frameworks with a high nitrogen content (12.1 mol%) along with low surface area 285 m2 g-1 present high specific capacities of the 308 and 200 F g-1 in KOH electrolyte at current densities of 0.1 and 10 A g-1, respectively, with very limited capacitance loss upon 10,000 cycles in both aqueous and gel electrolytes. Moreover, the electrode exhibits the highest capacitance up to 220 F g-1 at 0.1 A g-1 and excellent flexibility (with negligible capacitance loss under different bending angles) in the polyvinyl alcohol/KOH gel electrolyte. The observed excellent performance competes well with that found in the electrodes of similar 3D frameworks formed by graphene or CNTs. Therefore, the ultralow-cost and simply strategy here demonstrates great potential for scalable producing high-performance carbon-based supercapacitors in the industry.

  6. High nitrogen-containing cotton derived 3D porous carbon frameworks for high-performance supercapacitors

    Science.gov (United States)

    Fan, Li-Zhen; Chen, Tian-Tian; Song, Wei-Li; Li, Xiaogang; Zhang, Shichao

    2015-01-01

    Supercapacitors fabricated by 3D porous carbon frameworks, such as graphene- and carbon nanotube (CNT)-based aerogels, have been highly attractive due to their various advantages. However, their high cost along with insufficient yield has inhibited their large-scale applications. Here we have demonstrated a facile and easily scalable approach for large-scale preparing novel 3D nitrogen-containing porous carbon frameworks using ultralow-cost commercial cotton. Electrochemical performance suggests that the optimal nitrogen-containing cotton-derived carbon frameworks with a high nitrogen content (12.1 mol%) along with low surface area 285 m2 g−1 present high specific capacities of the 308 and 200 F g−1 in KOH electrolyte at current densities of 0.1 and 10 A g−1, respectively, with very limited capacitance loss upon 10,000 cycles in both aqueous and gel electrolytes. Moreover, the electrode exhibits the highest capacitance up to 220 F g−1 at 0.1 A g−1 and excellent flexibility (with negligible capacitance loss under different bending angles) in the polyvinyl alcohol/KOH gel electrolyte. The observed excellent performance competes well with that found in the electrodes of similar 3D frameworks formed by graphene or CNTs. Therefore, the ultralow-cost and simply strategy here demonstrates great potential for scalable producing high-performance carbon-based supercapacitors in the industry. PMID:26472144

  7. 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...

  8. 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...

  9. 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.)

  10. High contrast enhancement aspect of dynamic computed tomography with arterial infusion - DCT-AI

    International Nuclear Information System (INIS)

    Kato, Seishi; Iwasaki, Naoya; Matsumura, Yoshimitsu; Kuramae, Shigeru; Mishiro, Tadashi

    1983-01-01

    Dynamic computed tomography was performed on 112 cases possibly having hepatic tumors with intraarterial infusion of undiluted contrast into a selectively placed catheter following angiographies. Our dynamic program could evaluate not only early phase of enhancement but also late phase up to 120 sec. Reconstructed views from early scans and magnified views were very useful to evaluate minute sequential changes. Hepatic masses less than 5 cm in size were found in thirty-one cases. Patterns of tumor enhancement and time-density curves have been analysed to correlate them with histology. Four types of tumor enhancement were noted: (1) homogeneous (2) patchy (3) mottled (4) ringed. Characteristic changes were observed in hepatocellular carcinoma - HCC - (mostly mottled) and haemangioma (mostly patchy). The former was divided in two groups reflecting the cellular maturity. The metastatic tumor could be enhanced in a ringed form with dendritic pattern of supplying vascularities in some cases. To support the use of undiluted contrast and to investigate the diagnostic efficacy of high contrast enhancement, experiments were performed by taking transaxial views of an acrylic phantom immersed in different concentrations of contrast. Analysis of CT images taken at different HU values ranging from 0 to 450 demonstrated that the higher the concentration of contrast, the better the spatial resolution was. Also larger magnification could be expected by using higher concentration of contrast. Although our Dynamic Computed Tomography with Arterial Infusion of Contrast still has drawbacks and limited indications, we advocate it as a better way of enhancement to detect and evaluate the hepatic masses, which sometimes elude the examiner's grasp with conventional way of enhancement. (author)

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

    OpenAIRE

    Markey, Oonagh; McClean, Conor M; Medlow, Paul; Davison, Gareth W; Trinick, Tom R; Duly, Ellie; Shafat, Amir

    2011-01-01

    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...

  12. 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.)

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

    International Nuclear Information System (INIS)

    Calcagni, Giulio; Gesualdo, Francesco; Brunelle, Francis; Ou, Phalla

    2008-01-01

    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.)

  14. 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

  15. 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

    International Nuclear Information System (INIS)

    Ryu, Seok Jong; Choi, Byoung Wook; Choe, Kyu Ok

    2001-01-01

    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

  16. Highly stable carbon-doped Cu films on barrierless Si

    International Nuclear Information System (INIS)

    Zhang, X.Y.; Li, X.N.; Nie, L.F.; Chu, J.P.; Wang, Q.; Lin, C.H.; Dong, C.

    2011-01-01

    Electrical resistivities and thermal stabilities of carbon-doped Cu films on silicon have been investigated. The films were prepared by magnetron sputtering using a Cu-C alloy target. After annealing at 400 deg. C for 1 h, the resistivity maintains a low level at 2.7 μΩ-cm and no Cu-Si reaction is detected in the film by X-ray diffraction (XRD) and transmission electron microscopy (TEM) observations. According to the secondary ion mass spectroscopy (SIMS) results, carbon is enriched near the interfacial region of Cu(C)/Si, and is considered responsible for the growth of an amorphous Cu(C)/Si interlayer that inhibits the Cu-Si inter-diffusion. Fine Cu grains, less than 100 nm, were present in the Cu(C) films after long-term and high-temperature annealings. The effect of C shows a combination of forming a self-passivated interface barrier layer and maintaining a fine-grained structure of Cu. A low current leakage measured on this Cu(C) film also provides further evidence for the carbon-induced diffusion barrier interlayer performance.

  17. HTGR fuel rods: carbon-carbon composites designed for high weight and low strength

    International Nuclear Information System (INIS)

    Bullock, R.E.

    1977-01-01

    The evolution of the process for fabricating fuel rods for the high-temperature gas-cooled reactor (HTGR) by injection and carbonization of a thermoplastic matrix that bonds close-packed beds of pyrocarbon-coated fuel particles together is reviewed for the fresh-fuel cycle, and a variant process involving a thermosetting matrix that would allow free-standing carbonization of refabricated fuel is discussed. Previous attempts to fabricate such injection-bonded fuel rods from undiluted thermosetting binders filled with powdered graphite were unsuccessful, because of damage to coatings on fuel particles that resulted from strong particle-to-matrix bonding in conjunction with large matrix shrinkage on carbonization and subsequent irradiation. These problems have now been overcome through the use of a diluted thermosetting matrix with a low-char-yield additive (fugitive), which produces a more porous char similar to that from the pitch-based thermoplastic used in fabrication of fresh fuel. A 1-to-1 dilution of resin with fugitive produced the optimum binder for injection and carbonization, where the fired matrix in such rods contained about 20 wt% binder char and 80 wt% powdered graphite. Thermosetting fuel rods diluted with various amounts of fugitive to give binder chars that range from 12 to 48 wt% of the fired matrix have been subjected to irradiation screening tests, and rods with no more than 32 wt% binder char appear to perform about as well under irradiation as do pitch-based rods. However, particle damage does begin to occur in those lightly diluted rods in which the less-stable binder char constitutes more than 32 wt% of the fired matrix. (author)

  18. Utilizing generalized autocalibrating partial parallel acquisition (GRAPPA) to achieve high-resolution contrast-enhanced MR angiography of hepatic artery: Initial experience in orthotopic liver transplantation candidates

    Energy Technology Data Exchange (ETDEWEB)

    Xu Pengju [Department of Radiology, Zhongshan Hospital, Fudan University, 180 Fenglin Road, Shanghai (China)]. E-mail: xpjbfc@163.com; Yan Fuhua [Department of Radiology, Zhongshan Hospital, Fudan University, 180 Fenglin Road, Shanghai (China)]. E-mail: yanfuhua@yahoo.com; Wang Jianhua [Department of Radiology, Zhongshan Hospital, Fudan University, 180 Fenglin Road, Shanghai (China); Lin Jiang [Department of Radiology, Zhongshan Hospital, Fudan University, 180 Fenglin Road, Shanghai (China); Fan Jia [Liver Cancer Institute, Zhongshan Hospital, Fudan University, 180 Fenglin Road, Shanghai (China)

    2007-03-15

    Objective: To evaluate feasibility of using GRAPPA to acquire high-resolution 3D contrast-enhanced MR angiography (CE-MRA) of hepatic artery and value of GRAPPA for displaying vessels anatomy. Materials and methods: High-resolution CE-MRA using GRAPPA was performed in 67 orthotopic liver transplantation recipient candidates. Signal intensity (SI) and relative SI, i.e., Cv-ro (vessel-to-liver contrast) of the aorta and the hepatic common artery (HCA), were measured. The SI and the relative SI were compared and analyzed using T-test. For purpose of qualitative evaluation, the vessel visualization quality and the order of depicted hepatic artery branches were evaluated by two radiologists independently and assessed by weighted kappa analysis. The depiction of hepatic arterial anatomy and variations was evaluated, and results were correlated with the findings in surgery. Results: The mean SI values were 283.29 {+-} 65.07 (mean {+-} S.D.) for aorta and 283.16 {+-} 64.07 for HCA, respectively. The mean relative SI values were 0.698 {+-} 0.09 for aorta and 0.696 {+-} 0.09 for HCA, respectively. Homogeneous enhancement between aorta and HCA was confirmed by statistically insignificant differences (p-values were 0.89 for mean SI values and 0.12 for mean relative SI values, respectively). The average score for vessel visualization ranged from good to excellent for different artery segments. Overall interobserver agreement in the visualization of different artery segments was excellent (kappa value > 0.80). The distal intrahepatic segmental arteries were well delineated for majority of patients with excellent interobserver agreement. Normal hepatic arterial anatomy was correctly demonstrated in 53 patients, and arterial anomalies were accurately detected on high-resolution MRA image of all 14 patients. Conclusion: High-resolution hepatic artery MRA acquired using GRAPPA in a reproducible manner excellently depicts and delineates small vessels and can be routinely used for

  19. Oxidation kinetics and mechanisms of carbon/carbon composites and their components in water vapour at high temperatures

    International Nuclear Information System (INIS)

    Qin, Fei; Peng, Li-na; He, Guo-qiang; Li, Jiang; Yan, Yong

    2015-01-01

    Highlights: • 4D-C/C composite was fabricated using carbon fibre and coal tar pitch. • The rate of mass loss and oxidation kinetics parameters of fibres-H 2 O and matrix-H 2 O are obtained. • The rate of mass loss and oxidation kinetics parameters of C/C–H 2 O are obtained. • Oxidation rate of the fibre bundle is greater than the oxidation rate of the matrix. - Abstract: Thermogravimetric analysis and scanning electron microscopy were used to study the oxidation kinetics of four-direction carbon/carbon composites and their components (fibres and matrices) in a H 2 O–Ar atmosphere at high temperatures. The oxidation processes were restricted to reaction-limited oxidation. The rate of mass loss was estimated for the four-direction carbon/carbon composites and their components at high temperature. The pressure exponent for the reaction of the carbon/carbon composites with H 2 O was 0.59, and the pre-exponential factor and activation energy for the reactions of H 2 O with the carbon/carbon composites, carbon fibres and matrices were determined

  20. High speed capacitor-inverter based carbon nanotube full adder.

    Science.gov (United States)

    Navi, K; Rashtian, M; Khatir, A; Keshavarzian, P; Hashemipour, O

    2010-03-18

    Carbon Nanotube filed-effect transistor (CNFET) is one of the promising alternatives to the MOS transistors. The geometry-dependent threshold voltage is one of the CNFET characteristics, which is used in the proposed Full Adder cell. In this paper, we present a high speed Full Adder cell using CNFETs based on majority-not (Minority) function. Presented design uses eight transistors and eight capacitors. Simulation results show significant improvement in terms of delay and power-delay product in comparison to contemporary CNFET Adder Cells. Simulations were carried out using HSPICE based on CNFET model with 0.6 V VDD.

  1. Off-pump Coronary Artery Bypass Graft in a High Risk Patient ...

    African Journals Online (AJOL)

    On-pump coronary artery bypass graft (CABG) entails the use of cardiopulmonary bypass (CPB). The procedure is safe but it's not without complications like neurocognitive deficits, cerebrovascular accidents, myocardial ischemic injury and activation of inflammatory pathways that contribute to pulmonary, renal, hematologic ...

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

    Centers for Disease Control (CDC) Podcasts

    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.

  3. High carbon microalloyed martensitic steel with ultrahigh strength-ductility

    Energy Technology Data Exchange (ETDEWEB)

    Qin, Shengwei; Liu, Yu; Hao, Qingguo [School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Wang, Ying [School of Mechanical Engineering, Shanghai Dianji University, Shanghai 200245 (China); Chen, Nailu, E-mail: nlchen@sjtu.edu.cn [School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Zuo, Xunwei; Rong, Yonghua [School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China)

    2016-04-29

    Based on the idea of rising the mechanical stability of retained austenite by the addition of Si in Fe-Mn based steels, an Fe-0.63C-1.52Mn-1.49Si-0.62Cr-0.036Nb was designed, then its hot rolled plate was successively tread by normalization process as pretreatment of novel quenching-partitioning-tempering (Q-P-T) process. Product of tensile and elongation (PSE) of 53.94 GPa% were obtained for this high carbon Q-P-T martensitic steel, and the PSE (40.18 GPa%) obtained by the conversion of tensile sample size using Oliver formula still is more excellent PSE than those of other microalloyed advanced high strength steels reported. The microstructural characterization reveals origin of ultrahigh PSE resulting from both the increase of considerable and dispersed carbon enriched retained austenite with relative high mechanical stability in volume fraction and the decrease of brittle twin-type martensite with the sensitivity of notch.

  4. EFFECT OF OBSTRUCTIVE SLEEP APNEA SYNDROME ON ARTERIAL STIFFNESS IN PATIENTS AT HIGH CARDIOVASCULAR RISK

    Directory of Open Access Journals (Sweden)

    V. E. Oleynikov

    2016-01-01

    Full Text Available Aim. To assess the impact of metabolic abnormalities in combination with obstructive sleep apnea on endothelial function and vascular stiffness parameters in patients with arterial hypertension 1-2 degrees. Material and methods. Patients (n=74 with metabolic syndrome and obstructive sleep apnea were included into the study. All patients underwent cardiorespiratory monitoring of sleep using SomnoCheck2 device (Wiennmann, Germany and were divided into two groups based on its results. Patients with apnea-hypopnea index (AHI <30 episodes per hour were included into group 1 and patients with AHI >30 episodes per hour – into group 2. Monitoring of ambulatory blood pressure (BP and arterial stiffness was performed by the device BPLab ("Peter Telegin", Russia. Endothelial function was assessed in a probe of flow-mediated dilation by the ultrasound device MyLab 90 (Esaote, Italy. Diameter of the common carotid artery (DCCA and the intima-media thickness (IMT were determined. Results. Patients with AHI >30 episodes per hour had higher mean daily and night systolic BP and pulse BP in aorta and brachial artery. Pulse wave velocity in aorta in per day averaged was also higher in these patients (8.2±0.8 vs 9.1±1.1 m/sec; p<0.05. Mean level of flow-mediated dilation was significantly lower in patients with severe sleep apnea> (8.8% (5.6; 13.1 vs 4.5% (2.2; 8.0; p<0.05. Prevalence of negative index of reactivity in group 2 was 2 times higher than this in group 1. An increase in IMT and DCCA in patients with severe obstructive sleep apnea was also revealed. Conclusion. Severe sleep apnea in patients with metabolic syndrome in combination with hypertension aggravates structural changes and endothelial dysfunction of the main arteries, as well as contributes to the progression of atherosclerosis.

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

    Science.gov (United States)

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

    2011-11-15

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

  6. Direct synthesis of highly porous interconnected carbon nanosheets and their application as high-performance supercapacitors.

    Science.gov (United States)

    Sevilla, Marta; Fuertes, Antonio B

    2014-05-27

    An easy, one-step procedure is proposed for the synthesis of highly porous carbon nanosheets with an excellent performance as supercapacitor electrodes. The procedure is based on the carbonization of an organic salt, i.e., potassium citrate, at a temperature in the 750-900 °C range. In this way, carbon particles made up of interconnected carbon nanosheets with a thickness of <80 nm are obtained. The porosity of the carbon nanosheets consists essentially of micropores distributed in two pore systems of 0.7-0.85 nm and 0.95-1.6 nm. Importantly, the micropore sizes of both systems can be enlarged by simply increasing the carbonization temperature. Furthermore, the carbon nanosheets possess BET surface areas in the ∼1400-2200 m(2) g(-1) range and electronic conductivities in the range of 1.7-7.4 S cm(-1) (measured at 7.1 MPa). These materials behave as high-performance supercapacitor electrodes in organic electrolyte and exhibit an excellent power handling ability and a superb robustness over long-term cycling. Excellent results were obtained with the supercapacitor fabricated from the material synthesized at 850 °C in terms of both gravimetric and volumetric energy and power densities. This device was able to deliver ∼13 Wh kg(-1) (5.2 Wh L(-1)) at an extremely high power density of 78 kW kg(-1) (31 kW L(-1)) and ∼30 Wh kg(-1) (12 Wh L(-1)) at a power density of 13 kW kg(-1) (5.2 kW L(-1)) (voltage range of 2.7 V).

  7. Converting biomass waste into microporous carbon with simultaneously high surface area and carbon purity as advanced electrochemical energy storage materials

    Science.gov (United States)

    Sun, Fei; Wang, Lijie; Peng, Yiting; Gao, Jihui; Pi, Xinxin; Qu, Zhibin; Zhao, Guangbo; Qin, Yukun

    2018-04-01

    Developing carbon materials featuring both high accessible surface area and high structure stability are desirable to boost the performance of constructed electrochemical electrodes and devices. Herein, we report a new type of microporous carbon (MPC) derived from biomass waste based on a simple high-temperature chemical activation procedure. The optimized MPC-900 possesses microporous structure, high surface area, partially graphitic structure, and particularly low impurity content, which are critical features for enhancing carbon-based electrochemical process. The constructed MPC-900 symmetric supercapacitor exhibits high performances in commercial organic electrolyte such as widened voltage window up to 3 V and thereby high energy/power densities (50.95 Wh kg-1 at 0.44 kW kg-1; 25.3 Wh kg-1 at 21.5 kW kg-1). Furthermore, a simple melt infiltration method has been employed to enclose SnO2 nanocrystals onto the carbon matrix of MPC-900 as a high-performance lithium storage material. The obtained SnO2-MPC composite with ultrafine SnO2 nanocrystals delivers high capacities (1115 mAh g-1 at 0.2 A g-1; 402 mAh g-1 at 10 A g-1) and high-rate cycling lifespan of over 2000 cycles. This work not only develops a microporous carbon with high carbon purity and high surface area, but also provides a general platform for combining electrochemically active materials.

  8. Comparison of diamond-like carbon-coated nitinol stents with or without polyethylene glycol grafting and uncoated nitinol stents in a canine iliac artery model

    Science.gov (United States)

    Kim, J H; Shin, J H; Shin, D H; Moon, M-W; Park, K; Kim, T-H; Shin, K M; Won, Y H; Han, D K; Lee, K-R

    2011-01-01

    Objective Neointimal hyperplasia is a major complication of endovascular stent placement with consequent in-stent restenosis or occlusion. Improvements in the biocompatibility of stent designs could reduce stent-associated thrombosis and in-stent restenosis. We hypothesised that the use of a diamond-like carbon (DLC)-coated nitinol stent or a polyethylene glycol (PEG)-DLC-coated nitinol stent could reduce the formation of neointimal hyperplasia, thereby improving stent patency with improved biocompatibility. Methods A total of 24 stents were implanted, under general anaesthesia, into the iliac arteries of six dogs (four stents in each dog) using the carotid artery approach. The experimental study dogs were divided into three groups: the uncoated nitinol stent group (n = 8), the DLC-nitinol stent group (n = 8) and the PEG-DLC-nitinol stent group (n = 8). Results The mean percentage of neointimal hyperplasia was significantly less in the DLC-nitinol stent group (26.7±7.6%) than in the nitinol stent group (40.0±20.3%) (p = 0.021). However, the mean percentage of neointimal hyperplasia was significantly greater in the PEG-DLC-nitinol stent group (58.7±24.7%) than in the nitinol stent group (40.0±20.3%) (p = 0.01). Conclusion Our findings indicate that DLC-coated nitinol stents might induce less neointimal hyperplasia than conventional nitinol stents following implantation in a canine iliac artery model; however, the DLC-coated nitinol stent surface when reformed with PEG induces more neointimal hyperplasia than either a conventional or DLC-coated nitinol stent. PMID:21325363

  9. Carotid artery stenting in high surgical risk patients using the FiberNet embolic protection system: the EPIC trial results.

    Science.gov (United States)

    Myla, Subbarao; Bacharach, J Michael; Ansel, Gary M; Dippel, Eric J; McCormick, Daniel J; Popma, Jeffrey J

    2010-05-01

    The multicenter EPIC (FiberNet Embolic Protection System in Carotid Artery Stenting Trial) single-arm trial evaluated the 30-day outcomes of a new design concept for embolic protection during carotid artery stenting (CAS). Embolic protection filters available for use during CAS include fixed and over-the-wire systems that rely on embolic material capture within a "basket" structure. The FiberNet Embolic Protection System (EPS), which features a very low crossing profile, consists of a three-dimensional fiber-based filter distally mounted on a 0.014 inch guidewire with integrated aspiration during filter retrieval. The trial enrolled 237 patients from 26 centers. Demographics, clinical and lesion characteristics, as well as adverse events through a 30-day follow-up were recorded. The mean age of the patients was 74 years, 64% were male and 20% had symptomatic carotid artery disease. The combined major adverse event (MAE) rate at 30 days for all death, stroke, and myocardial infarction was 3.0%. There were three major strokes (two ischemic and one hemorrhagic) and two minor strokes (both ischemic) for a 2.1% 30-day stroke rate. The procedural technical success rate was 97.5% and macroscopic evidence of debris was reported in 90.9% of the procedures. The FiberNet EPS, used with commercially available stents, produced low stroke rates following CAS in high surgical risk patients presenting with carotid artery disease. The unique filter design including aspiration during retrieval may have contributed to the low 30-day stroke rate reported during CAS in patients considered at high risk for complications following carotid endarterectomy (CEA). Copyright 2010 Wiley-Liss, Inc.

  10. Fabrication of mesoporous and high specific surface area lanthanum carbide-carbon nanotube composites

    International Nuclear Information System (INIS)

    Biasetto, L.; Carturan, S.; Maggioni, G.; Zanonato, P.; Bernardo, P. Di; Colombo, P.; Andrighetto, A.; Prete, G.

    2009-01-01

    Mesoporous lanthanum carbide-carbon nanotube composites were produced by means of carbothermal reaction of lanthanum oxide, graphite and multi-walled carbon nanotube mixtures under high vacuum. Residual gas analysis revealed the higher reactivity of lanthanum oxide towards carbon nanotubes compared to graphite. After sintering, the composites revealed a specific surface area increasing with the amount of carbon nanotubes introduced. The meso-porosity of carbon nanotubes was maintained after thermal treatment.

  11. Effect of high pressure hydrogen on the mechanical characteristics of single carbon fiber

    Science.gov (United States)

    Jeon, Sang Koo; Kwon, Oh Heon; Jang, Hoon-Sik; Ryu, Kwon Sang; Nahm, Seung Hoon

    2018-02-01

    In this study, carbon fiber was exposed to a pressure of 7 MPa for 24 h in high pressure chamber. The tensile test for carbon fiber was conducted to estimate the effect on the high pressure hydrogen in the atmosphere. To determine the tensile strength and Weibull modulus, approximately thirty carbon fiber samples were measured in all cases, and carbon fiber exposed to high pressure argon was evaluated to verify only the effect of hydrogen. Additionally, carbon fiber samples were annealed at 1950 °C for 1 h for a comparison with normal carbon fiber and then tested under identical conditions. The results showed that the tensile strength scatter of normal carbon fiber exposed to hydrogen was relatively wider and the Weibull modulus was decreased. Moreover, the tensile strength of the annealed carbon fiber exposed to hydrogen was increased, and these samples indicated a complex Weibull modulus because the hydrogen stored in the carbon fiber influenced the mechanical characteristic.

  12. Tobacco Stem-Based Activated Carbons for High Performance Supercapacitors

    Science.gov (United States)

    Xia, Xiaohong; Liu, Hongbo; Shi, Lei; He, Yuede

    2012-09-01

    Tobacco stem-based activated carbons (TS-ACs) were prepared by simple KOH activation and their application as electrodes in the electrical double layer capacitor (EDLC) performed successfully. The BET surface area, pore volume, and pore size distribution of the TS-ACs were evaluated based on N2 adsorption isotherms at 77 K. The surface area of the obtained activated carbons varies over a wide range (1472.8-3326.7 m2/g) and the mesoporosity was enhanced significantly as the ratio of KOH to tobacco stem (TS) increased. The electrochemical behaviors of series TS-ACs were characterized by means of galvanostatic charging/discharging, cyclic voltammetry, and impedance spectroscopy. The correlation between electrochemical properties and pore structure was investigated. A high specific capacitance value as 190 F/g at 1 mA/cm2 was obtained in 1 M LiPF6-EC/DMC/DEC electrolyte solution. Furthermore, good performance is also achieved even at high current densities. A development of new use for TS into a valuable energy storage material is explored.

  13. 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.

  14. Activated polyaniline-based carbon nanoparticles for high performance supercapacitors

    International Nuclear Information System (INIS)

    Zhou, Jin; Zhu, Tingting; Xing, Wei; Li, Zhaohui; Shen, Honglong; Zhuo, Shuping

    2015-01-01

    Polyaniline (PANI) nanoparticles have been prepared by disperse polymerization of aniline in the presence of poly(4-styrenesulfonate). The PANI nanoparticles are further subjected to pyrolysis treatment and chemical-activation to prepare the activated nitrogen-doped carbon nanoparticles (APCNs). The porosity, structure and nitrogen-doped surface chemistry are analyzed by a varies of means, such as scanning electron microscopy, transition electron microscopy, N 2 sorption, X-ray diffraction and X-ray photoelectron spectroscopy. The capacitive performance of the APCNs materials are test in 6 M KOH electrolyte. Benefitting from the abundant micropores with short length, large specific surface area, hierarchical porosity and heteroatom-doped polar pore surface, the APCNs materials exhibit v exhibit very high specific capacitance up to 341 F g −1 , remarkable power capability and excellent long-term cyclic stability (96.6% after 10 000 cycles). At 40 A g −1 , APCN-2 carbon shows a capacitance of 164 F g −1 , responding to a high energy and power densities of 5.7 Wh kg −1 and 10 000 W kg −1

  15. 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.

  16. High performance thiol-ene thermosets based on fully bio-based poly(limonene carbonate)s

    NARCIS (Netherlands)

    Li, C.; Johansson, M.; Sablong, R.J.; Koning, C.E.

    2017-01-01

    High glass transition temperature (Tg) thiol-ene networks (TENs) based on poly(limonene carbonate)s (PLCs), derived from orange oils and of potential degradability are described here. PLCs with moderate molecular weight were prepared by copolymerization of limonene oxide with CO2 and subsequent

  17. 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

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

    Science.gov (United States)

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

    2008-01-01

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

  19. Effects of carbonated mineral water treatment in Băile Tuşnad on chronic arterial occlusive disease – a case report

    Directory of Open Access Journals (Sweden)

    Gabriela Dogaru

    2017-05-01

    Full Text Available Introduction. Băile Tușnad spa is recognized for its role in the prevention and rehabilitation treatment of cardiovascular diseases, including chronic arterial occlusive disease, due to the presence of natural therapeutic factors: carbonated mineral waters through their peripheral vasodilator effects, natural mofettes, stimulating bioclimate. Aim. The current study aimed to assess the clinical efficiency of natural therapeutic factors in Băile Tuşnad for the continuation of rehabilitation treatment in a patient with chronic arterial occlusive disease, in order to encourage walking, reduce cardiovascular risk and improve quality of life. Material and method. Patient N.M., aged 75, with multiple cardiovascular risk factors. In 2013, he was diagnosed with lower limb peripheral ischemia syndrome stage II B Fontaine, predominantly left claudication at about 100 m, for which balloon angioplasty was performed. He attended rehabilitation treatment for 3 years in Baile Tuşnad, consisting of carbonated mineral water baths for 15 minutes, aerotherapy for 30 minutes daily for the stimulation of walking, massotherapy, kinesiotherapy, performed daily for 16 days, and in 2016, at the Rehabilitation Hospital Cluj-Napoca. He was clinically evaluated before and at the end of treatment by the Visual Analogue Scale, the 10-m walking test, adverse reactions, Doppler ultrasound. Results. At the end of treatment, an increase in the walking distance and speed, a significant improvement in the quality of gait was found; claudication occurred after 250 m, pain in the lower limbs was improved. There were no side reactions. Conclusions. Rehabilitation treatment with natural therapeutic factors influenced the clinical and functional picture, determining a significant improvement in the quality of gait and quality of life.

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

    International Nuclear Information System (INIS)

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

    2015-01-01

    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 × 10 6 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. (paper)

  1. 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

  2. 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.

  3. 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.)

  4. 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.

  5. Energy Saving High-Capacity Moderate Pressure Carbon Dioxide Storage System, Phase I

    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...

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

    Science.gov (United States)

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

    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 x 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 degrees C. No significant influence of pH on adsorption was observed at pH 3 to 9; however, adsorption capacity decreased dramatically from pH 9 to 13.

  7. High dispersity of carbon nanotubes diminishes immunotoxicity in spleen.

    Science.gov (United States)

    Lee, Soyoung; Khang, Dongwoo; Kim, Sang-Hyun

    2015-01-01

    From the various physiochemical material properties, the chemical functionalization order of single-walled carbon nanotubes (swCNTs) has not been considered as a critical factor for modulating immunological responses and toxicological aspects in drug delivery applications. Although most nanomaterials, including carbon nanotubes, are specifically accumulated in spleen, few studies have focused on spleen immunotoxicity. For this reason, this study demonstrated that the dispersity of swCNTs significantly influenced immunotoxicity in vitro and in vivo. For cytotoxicity of swCNTs, MTT assay, reactive oxygen species production, superoxide dismutase activity, cellular uptake, and confocal microscopy were used in macrophages. In the in vivo study, female BALB/c mice were intravenously administered with 1 mg/kg/day of swCNTs for 2 weeks. The body weight, organ weight, hematological change, reverse-transcription polymerase chain reaction, and lymphocyte population were evaluated. Different orders of chemical functionalization of swCNTs controlled immunotoxicity. In short, less-dispersed swCNTs caused cytotoxicity in macrophages and abnormalities in immune organs such as spleen, whereas highly dispersed swCNTs did not result in immunotoxicity. This study clarified that increasing carboxyl groups on swCNTs significantly mitigated immunotoxicity in vitro and in vivo. Our findings clarified the effective immunotoxicological factors of swCNTs by increasing dispersity of swCNTs and provided useful guidelines for the effective use of nanomaterials.

  8. Oxidation kinetics and mechanisms of four-direction carbon/carbon composites and their components in carbon dioxide at high temperature

    International Nuclear Information System (INIS)

    Qin, Fei; Peng, Li-na; He, Guo-qiang; Li, Jiang

    2013-01-01

    Highlights: •Four-direction C/C composite was fabricated using carbon fibres and coal tar pitches. •Large-sized bulk matrix was prepared using same process as matrix of C/C composites. •A and E a of C/C, bulk matrix and fibres in CO 2 were determined, respectively. •Pressure exponent n was 0.62 in C/C–CO 2 . -- Abstract: Thermogravimetric analysis and scanning electron microscopy were used to study the oxidation kinetics of four-direction carbon/carbon composites and their components (fibres and matrix) in a CO 2 atmosphere at high temperature. The ablation processes were restricted to reaction-limited oxidation. The mass loss rate was estimated for the four-direction carbon/carbon composites and their components within the temperature of range of 600–1400 °C. The pressure exponent for the reaction of carbon/carbon composites and CO 2 was 0.62, and the pre-exponential factor and activation energy for the reactions of CO 2 and the carbon/carbon composites, carbon fibres and matrix were determined, respectively

  9. 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

  10. 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

  11. Prognostic Value of Coronary Computed Tomography Imaging in Patients at High Risk Without Symptoms of Coronary Artery Disease.

    Science.gov (United States)

    Dedic, Admir; Ten Kate, Gert-Jan R; Roos, Cornelis J; Neefjes, Lisan A; de Graaf, Michiel A; Spronk, Angela; Delgado, Victoria; van Lennep, Jeanine E Roeters; Moelker, Adriaan; Ouhlous, Mohamed; Scholte, Arthur J H A; Boersma, Eric; Sijbrands, Eric J G; Nieman, Koen; Bax, Jeroen J; de Feijter, Pim J

    2016-03-01

    At present, traditional risk factors are used to guide cardiovascular management of asymptomatic subjects. Intensified surveillance may be warranted in those identified as high risk of developing cardiovascular disease (CVD). This study aims to determine the prognostic value of coronary computed tomography (CT) angiography (CCTA) next to the coronary artery calcium score (CACS) in patients at high CVD risk without symptoms suspect for coronary artery disease (CAD). A total of 665 patients at high risk (mean age 56 ± 9 years, 417 men), having at least one important CVD risk factor (diabetes mellitus, familial hypercholesterolemia, peripheral artery disease, or severe hypertension) or a calculated European systematic coronary risk evaluation of >10% were included from outpatient clinics at 2 academic centers. Follow-up was performed for the occurrence of adverse events including all-cause mortality, nonfatal myocardial infarction, unstable angina, or coronary revascularization. During a median follow-up of 3.0 (interquartile range 1.3 to 4.1) years, adverse events occurred in 40 subjects (6.0%). By multivariate analysis, adjusted for age, gender, and CACS, obstructive CAD on CCTA (≥50% luminal stenosis) was a significant predictor of adverse events (hazard ratio 5.9 [CI 1.3 to 26.1]). Addition of CCTA to age, gender, plus CACS, increased the C statistic from 0.81 to 0.84 and resulted in a total net reclassification index of 0.19 (p value and risk reclassification benefit beyond CACS in patients without CAD symptoms but with high risk of developing CVD. Copyright © 2016 Elsevier Inc. All rights reserved.

  12. High methanol oxidation activity of electrocatalysts supported by directly grown nitrogen-containing carbon nanotubes on carbon cloth

    International Nuclear Information System (INIS)

    Wang, C.-H.; Shih, H.-C.; Tsai, Y.-T.; Du, H.-Y.; Chen, L.-C.; Chen, K.-H.

    2006-01-01

    The microstructure and electrochemical activity of the Pt-Ru supported by nitrogen-containing carbon nanotubes (CN x NTs) directly grown on the carbon cloth have been investigated. The CN x NTs directly grown on the carbon cloth (CN x NTs-carbon cloth composite electrode) were synthesized using microwave-plasma-enhanced chemical vapour deposition first and then use as the template to support the Pt-Ru nanoclusters subsequently sputtered on. The ferricyanide/ferrocyanide redox reaction in cyclic voltammetry (CV) measurements showed a faster electron transfer on the CN x NTs-carbon cloth composite electrode than the one with carbon cloth alone. Comparing their methanol oxidation abilities, it is found that the Pt-Ru nanoclusters supported by the CN x NTs-carbon cloth composite electrode have considerably higher electrocatalytic activity than the carbon cloth counterpart. This result suggests high performance of the CN x NTs-carbon cloth composite electrode, and demonstrates its suitability for direct methanol fuel cell applications

  13. High methanol oxidation activity of electrocatalysts supported by directly grown nitrogen-containing carbon nanotubes on carbon cloth

    Energy Technology Data Exchange (ETDEWEB)

    Wang, C.-H. [Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu, Taiwan (China); Shih, H.-C. [Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu, Taiwan (China); Institue of Materials Science and Nano Technology, Chinese Culture University, Taipei, Taiwan (China); Tsai, Y.-T. [Institue of Materials Science and Nano Technology, Chinese Culture University, Taipei, Taiwan (China); Du, H.-Y. [Institue of Materials Science and Nano Technology, Chinese Culture University, Taipei, Taiwan (China); Chen, L.-C. [Center for Condensed Matter Sciences, National Taiwan University, Taipei, Taiwan (China); Chen, K.-H. [Center for Condensed Matter Sciences, National Taiwan University, Taipei, Taiwan (China) and Institue of Atomic and Molecular Science, Academia Sinica, Taipei, Taiwan (China)]. E-mail: chenkh@pub.iams.sinica.edu.tw

    2006-12-01

    The microstructure and electrochemical activity of the Pt-Ru supported by nitrogen-containing carbon nanotubes (CN {sub x} NTs) directly grown on the carbon cloth have been investigated. The CN {sub x} NTs directly grown on the carbon cloth (CN {sub x} NTs-carbon cloth composite electrode) were synthesized using microwave-plasma-enhanced chemical vapour deposition first and then use as the template to support the Pt-Ru nanoclusters subsequently sputtered on. The ferricyanide/ferrocyanide redox reaction in cyclic voltammetry (CV) measurements showed a faster electron transfer on the CN {sub x} NTs-carbon cloth composite electrode than the one with carbon cloth alone. Comparing their methanol oxidation abilities, it is found that the Pt-Ru nanoclusters supported by the CN {sub x} NTs-carbon cloth composite electrode have considerably higher electrocatalytic activity than the carbon cloth counterpart. This result suggests high performance of the CN {sub x} NTs-carbon cloth composite electrode, and demonstrates its suitability for direct methanol fuel cell applications.

  14. Nano-micro carbon spheres anchored on porous carbon derived from dual-biomass as high rate performance supercapacitor electrodes

    Science.gov (United States)

    Liu, Shaobo; Zhao, Yang; Zhang, Baihui; Xia, Hui; Zhou, Jianfei; Xie, Wenke; Li, Hongjian

    2018-03-01

    Hierarchical nano-micro carbon spheres@rice straw-derived porous carbon composites are successfully synthesized by the in situ decoration of the porous carbon with carbon spheres from glucose under the assistance of cetyltrimethyl ammonium bromide micelles and further activated by KOH. The scanning electron microscope images clearly show the carbon spheres disperse homogeneously and orderly onto the surface and in the inner macropores of the porous carbon. The diameter of the carbon spheres varies from 475 nm to 1.6 μm, which can be easily controlled by introducing extra inducing agent. The optimal composites exhibit a large specific surface area (1122 m2 g-1), rich content of oxygen (14.2 wt %), and tunable hierarchical porous structure. When used as supercapacitor electrodes, the novel composites with abundant fruits present a high specific capacitance of 337 F g-1 at 1 A g-1, excellent rate retention of 83% from 1 to 20 A g-1 and a good cycling stability with 96% capacitance retention after 10000 cycles. In this strategy, the thought of shared ion-buffering reservoirs is proposed and the mutual promotion effects between the carbon spheres and porous carbon in the composites are also practically demonstrated to contribute the enhanced electrochemical performances.

  15. 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

  16. Aloe vera Derived Activated High-Surface-Area Carbon for Flexible and High-Energy Supercapacitors.

    Science.gov (United States)

    Karnan, M; Subramani, K; Sudhan, N; Ilayaraja, N; Sathish, M

    2016-12-28

    Materials which possess high specific capacitance in device configuration with low cost are essential for viable application in supercapacitors. Herein, a flexible high-energy supercapacitor device was fabricated using porous activated high-surface-area carbon derived from aloe leaf (Aloe vera) as a precursor. The A. vera derived activated carbon showed mesoporous nature with high specific surface area of ∼1890 m 2 /g. A high specific capacitance of 410 and 306 F/g was achieved in three-electrode and symmetric two-electrode system configurations in aqueous electrolyte, respectively. The fabricated all-solid-state device showed a high specific capacitance of 244 F/g with an energy density of 8.6 Wh/kg. In an ionic liquid electrolyte, the fabricated device showed a high specific capacitance of 126 F/g and a wide potential window up to 3 V, which results in a high energy density of 40 Wh/kg. Furthermore, it was observed that the activation temperature has significant role in the electrochemical performance, as the activated sample at 700 °C showed best activity than the samples activated at 600 and 800 °C. The electron microscopic images (FE-SEM and HR-TEM) confirmed the formation of pores by the chemical activation. A fabricated supercapacitor device in ionic liquid with 3 V could power up a red LED for 30 min upon charging for 20s. Also, it is shown that the operation voltage and capacitance of flexible all-solid-state symmetric supercapacitors fabricated using aloe-derived activated carbon could be easily tuned by series and parallel combinations. The performance of fabricated supercapacitor devices using A. vera derived activated carbon in all-solid-state and ionic liquid indicates their viable applications in flexible devices and energy storage.

  17. Geckolike high shear strength by carbon nanotube fiber adhesives

    Science.gov (United States)

    Maeno, Y.; Nakayama, Y.

    2009-01-01

    Carbon nanotube adhesives can adhere strongly to surfaces as a gecko does. The number of carbon nanotube layers is an important determinant of the contact area for adhesion. Balancing the catalyst ratio and buffer layer used for chemical vapor deposition processing controls the number of carbon nanotube layers and their distribution. The features of carbon nanotubes determine the shear strength of adhesion. Carbon nanotubes with a broad distribution of layers exhibit enhanced shear strength with equivalent adhesive capability to that of a natural Tokay Gecko (Gekko gecko)

  18. 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.

  19. High electron thermal conductivity of chiral carbon nanotubes

    International Nuclear Information System (INIS)

    Mensah, S.Y.; Allotey, F.K.A.; Nkrumah, George; Mensah, N.G.

    2003-11-01

    Solving the Boltzmann kinetic equation with energy dispersion relation obtained in the tight binding approximation, the carrier thermal conductivity κ e of a chiral carbon nanotube (CCNT) was determined. The dependence of κ e on temperature T, chiral geometric angle φ h and overlap integrals Δ z and Δ s were obtained. The results were numerically analysed. Unusually high values of κ e were observed suggesting that ne is nontrivial in the calculation of the thermal conductivity κ of CCNT. More interestingly we noted also that at 104 K and for Δ z and Δ s values of 0.020 eV and 0.0150 eV respectively the κ e value is about 41000 W/mK as reported for a 99.9% pure 12 C crystal. We predict that the electron thermal conductivity of CCNT should exceed 200,000 W/mK at ∼ 80 K. (author)

  20. Evaporation of carbon using electrons of a high density plasma

    International Nuclear Information System (INIS)

    Muhl, S.; Camps, E.; Escobar A, L.; Garcia E, J.L.; Olea, O.

    1999-01-01

    The high density plasmas are used frequently in the preparation of thin films or surface modification, for example to nitridation. In these processes, are used mainly the ions and the neutrals which compose the plasma. However, the electrons present in the plasma are not used, except in the case of chemical reactions induced by collisions, although the electron bombardment usually get hot the work piece. Through the adequate polarization of a conductor material, it is possible to extract electrons from a high density plasma at low pressure, that could be gotten the evaporation of this material. As result of the interaction between the plasma and the electron flux with the vapor produced, this last will be ionized. In this work, it is reported the use of this novelty arrangement to prepare carbon thin films using a high density argon plasma and a high purity graphite bar as material to evaporate. It has been used substrates outside plasma and immersed in the plasma. Also it has been reported the plasma characteristics (temperature and electron density, energy and ions flux), parameters of the deposit process (deposit rate and ion/neutral rate) as well as the properties of the films obtained (IR absorption spectra and UV/Vis, elemental analysis, hardness and refractive index. (Author)

  1. 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......-infarct-related epicardial coronary arteries (non-IRA) after successful primary PCI. Patients were treated with high-intensity rosuvastatin (40 mg/day) throughout 13 months and serial intracoronary imaging with the analysis of matched segments was available for 82 patients with 146 non-IRA. The primary IVUS end...

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

    Science.gov (United States)

    Cui, Xiaoming; Li, Tao; Li, Xin; Zhou, Weihua

    2015-05-01

    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. 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. 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. 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. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  3. High-dose superselective intra-arterial cisplatin and concomitant radiation therapy for carcinoma of the oral cavity

    International Nuclear Information System (INIS)

    Suzuki, Gen; Tanaka, Norimitsu; Ogo, Etuyo

    2007-01-01

    The purpose of this study was to evaluate the effect of high-dose superselective intra-arterial cisplatin and concomitant radiation therapy for carcinoma of the oral cavities. The subjects consisted of 18 patients with carcinoma of the oral, and cavity treated with superselective intra-arterial infusion of high dose cisplatin (100 mg/body) concomitant with delivery of external beam radiotherapy (median total dose, 60.8 Gy) between 2001 and 2004. Sodium thiosulfate was administered intravenously to provide effective cisplatin neutlization. They were International Union Against Cancer (UICC)1997 stage II-IV (stage II: 4 patients, stage III: 4 patients, stage IV: 10 patients). Patients ranged from 43-81 years of age, with a median of 60 years, and included 14 men and 4 women. A follow-up period was 6 months minimum from the atart of the radiation therapy, the median follow up period at 28 months. The three-year overall survival rate was 71%. The three-year disease free rate and local control rate were 60% and 65%, respectively. Three-year local control rate of the T2-3 was achieved at 83%, and that for T4 at 50%. There was borderline significant difference in local control rate between T2-3 and T4 (p=0.05). We conclude that the high-dose superselective intra-arterial cisplatin and concomitant radiation therapy provides effective results in organ preservation for cancer of oral cavities. Further studies are also required to determine the validity of this method. (author)

  4. Physical Activity and Characteristics of the Carotid Artery Wall in High-Risk Patients-The SMART (Second Manifestations of Arterial Disease) Study.

    Science.gov (United States)

    Boss, H Myrthe; van der Graaf, Yolanda; Visseren, Frank L J; Van den Berg-Vos, Renske M; Bots, Michiel L; de Borst, Gert Jan; Cramer, Maarten J; Kappelle, L Jaap; Geerlings, Mirjam I

    2017-07-23

    Physical activity reduces the risk of vascular disease. This benefit is not entirely explained through an effect on vascular risk factors. We examined the relationship of physical activity and characteristics of the carotid artery wall in patients with vascular disease or risk factors. Cross-sectional analyses were performed in 9578 patients from the SMART (Second Manifestations of Arterial Disease) study, a prospective cohort study among patients with vascular disease or risk factors. Physical activity was assessed using questionnaires. Carotid intima-media thickness and carotid artery stenosis of both common carotid arteries was measured. In a subset of 3165 participants carotid diastolic diameter and distension were assessed. Carotid stiffness was expressed as the distensibility coefficient and Young's elastic modulus. Regression analyses adjusted for vascular risk factors showed that physical activity was inversely associated with diastolic diameter (fifth versus first quintile B=-0.13 mm; 95% CI, -0.21 to -0.05) and decreased risk of carotid artery stenosis (relative risk, 0.58; 95% CI, 0.48-0.69). A light level of physical activity was associated with less carotid stiffness (second versus first quintile; Young's elastic modulus B=-0.11 kPa -1 ×10 -3 ; 95% CI, -0.16 to -0.06; distensibility coefficient B=0.93 kPa×10 3 ; 95% CI, 0.34-1.51), but there was no additional benefit with increasing levels of physical activity. In patients with vascular disease, physical activity was inversely associated with common carotid intima-media thickness, but not in patients with vascular risk factors. In patients with vascular disease or risk factors, increased physical activity was associated with smaller carotid diastolic diameter, decreased risk of carotid artery stenosis, and less carotid stiffness, but it only showed benefits on carotid intima-media thickness in patients with vascular disease. © 2017 The Authors. Published on behalf of the American Heart

  5. High resolution of black carbon and organic carbon emissions in the Pearl River Delta region, China.

    Science.gov (United States)

    Zheng, Junyu; He, Min; Shen, Xingling; Yin, Shasha; Yuan, Zibing

    2012-11-01

    A high-resolution regional black carbon (BC) and organic carbon (OC) emission inventory for the year 2009 was developed for the Pearl River Delta (PRD) region, China, based on the collected activity data and the latest emission factors. PM(2.5), BC and OC emissions were estimated to be 303 kt, 39 kt and 31 kt, respectively. Industrial processes were major contributing sources to PM(2.5) emissions. BC emissions were mainly from mobile sources, accounting for 65.0%, while 34.1% of OC emissions were from residential combustion. The primary OC/BC ratios for individual cities in the PRD region were dependent on the levels of economic development due to differences in source characteristics, with high ratios in the less developed cities and low ratios in the central and southern developed areas. The preliminary temporal profiles were established, showing the highest OC emissions in winter and relatively constant BC emissions throughout the year. The emissions were spatially allocated into grid cells with a resolution of 3 km × 3 km. Large amounts of BC emissions were distributed over the central-southern PRD city clusters, while OC emissions exhibited a relatively even spatial distribution due to the significant biomass burning emissions from the outlying area of the PRD region. Uncertainties in carbonaceous aerosol emissions were usually higher than in other primary pollutants like SO(2), NO(x), and PM(10). One of the key uncertainty sources was the emission factor, due to the absence of direct measurements of BC and OC emission rates. Copyright © 2012 Elsevier B.V. All rights reserved.

  6. Genetics Home Reference: pulmonary arterial hypertension

    Science.gov (United States)

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

  7. 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

  8. 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...

  9. The Mechanism of High Ductility for Novel High-Carbon Quenching-Partitioning-Tempering Martensitic Steel

    Science.gov (United States)

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

    2015-09-01

    In this article, a novel quenching-partitioning-tempering (Q-P-T) process was applied to treat Fe-0.6C-1.5Mn-1.5Si-0.6Cr-0.05Nb hot-rolled high-carbon steel and the microstructures including retained austenite fraction and the average dislocation densities in both martensite and retained austenite were characterized by X-ray diffraction, scanning electron microscopy, and transmission electron microscopy, respectively. The Q-P-T steel exhibits high strength (1950 MPa) and elongation (12.4 pct). Comparing with the steel treated by traditional quenching and tempering (Q&T) process, the mechanism of high ductility for high-carbon Q-P-T steel is revealed as follows. Much more retained austenite existing in Q-P-T steel than in Q&T one remarkably enhances the ductility by the following two effects: the dislocation absorption by retained austenite effect and the transformation-induced plasticity effect. Besides, lower dislocation density in martensite matrix produced by Q-P-T process plays an important role in the improvement of ductility. However, some thin plates of twin-type martensite embedded in dislocation-type martensite matrix in high-carbon Q-P-T steel affect the further improvement of ductility.

  10. High tie versus low tie of the inferior mesenteric artery in colorectal cancer: A meta-analysis.

    Science.gov (United States)

    Yang, Yafan; Wang, Guiying; He, Jingli; Zhang, Jianfeng; Xi, Jinchuan; Wang, Feifei

    2018-04-01

    Colorectal cancer surgery includes "high tie" and "low tie"of the inferior mesenteric artery(IMA). However, different ligation level is closely related to the blood supply of anastomosis, which may increase the leakage rate, and it is unclear which technique confers a lower anastomotic leakage rate(AL) and survival advantage. To compare the effectiveness and impact of inferior mesenteric artery (IMA) high ligation versus IMA low ligation on anastomotic leakage, lymph nodes yield rates and 5-year survival. A list of these studies, published in English from 1990 to 2017, was obtained independently by two reviewers from databases such as PubMed, Medline, ScienceDirect and Web of Science. Anastomotic leakage rate, the yield of lymph nodes and 5-year survival were compared using Review Manager 5.3. There was no significant difference in anastomotic leakage, number of lymph nodes retrieved and 5-year survival rate for both techniques. Neither the high tie nor the low tie strategy has an evidence in terms of anastomotic leakage rate, harvested lymph nodes, and the 5-year survival rate. Further RCT is needed. Copyright © 2018 IJS Publishing Group Ltd. Published by Elsevier Ltd. All rights reserved.

  11. Spine-like Nanostructured Carbon Interconnected by Graphene for High-performance Supercapacitors

    Science.gov (United States)

    Park, Sang-Hoon; Yoon, Seung-Beom; Kim, Hyun-Kyung; Han, Joong Tark; Park, Hae-Woong; Han, Joah; Yun, Seok-Min; Jeong, Han Gi; Roh, Kwang Chul; Kim, Kwang-Bum

    2014-08-01

    Recent studies on supercapacitors have focused on the development of hierarchical nanostructured carbons by combining two-dimensional graphene and other conductive sp2 carbons, which differ in dimensionality, to improve their electrochemical performance. Herein, we report a strategy for synthesizing a hierarchical graphene-based carbon material, which we shall refer to as spine-like nanostructured carbon, from a one-dimensional graphitic carbon nanofiber by controlling the local graphene/graphitic structure via an expanding process and a co-solvent exfoliation method. Spine-like nanostructured carbon has a unique hierarchical structure of partially exfoliated graphitic blocks interconnected by thin graphene sheets in the same manner as in the case of ligaments. Owing to the exposed graphene layers and interconnected sp2 carbon structure, this hierarchical nanostructured carbon possesses a large, electrochemically accessible surface area with high electrical conductivity and exhibits high electrochemical performance.

  12. Measurements of Carbon Dioxide, Carbon Monoxide, and Other Related Tracers at High Spatial and Temporal Resolution in an Urban Environment

    Science.gov (United States)

    Rella, C.; Jacobson, G.

    2012-04-01

    The ability to quantify the sources and sinks of carbon dioxide on the urban scale is essential for understanding the atmospheric drivers to global climate change. In the 'top-down' approach, overall carbon fluxes are determined by combining remote measurements of carbon dioxide concentrations with complex atmospheric transport models, and these emissions measurements are compared to "bottoms-up" predictions based on detailed inventories of the sources and sinks of carbon, both anthropogenic and biogenic in nature. This approach, which has been proven to be effective at continental scales, becomes challenging to implement at the urban scale, due to poorly understood micrometeorological atmospheric transport models and high variability of the emissions sources in space (e.g., factories, highways, residences) and time (rush hours, factory shifts and shutdowns, residential energy usage variability during the day and over the year). New measurement and analysis techniques are required to make sense of the carbon dioxide signal in cities. Here we present detailed, high spatial- and temporal-resolution greenhouse gas measurements in Silicon Valley in California. The synthesis of two experimental campaigns is presented: real-time measurements from two ten-meter urban 'towers,' and ground-based mobile mapping measurements. Real-time carbon dioxide data from a nine-month period are combined with real-time carbon monoxide, methane, acetylene, and carbon 13 measurements to partition the observed CO2 concentrations between different anthropogenic sectors (e.g., transport, residential) and biogenic sources. The carbon monoxide to carbon dioxide ratio is shown to vary over more than a factor of two from season to season or even from day to night, indicating rapid and frequent shifts in the balance between different carbon dioxide sources. Clear differences are seen between the two urban sites, which are separated by 7 km. Further information is given by the carbon 13 signature

  13. [High percentage of obesity during childhood and adolescence and subsequent increases in childhood arterial hypertension].

    Science.gov (United States)

    Menghetti, E; Carletti, M; Strisciuglio, P; Spagnolo, A

    2010-04-01

    The main objective of the study was to assess the prevalence of obesity, overweight and blood hypertension amongst children and adolescents. The study enrolled 2045 students between 6 and 17 years of age in three Italian cities, Varese (in the North), Rome (in the Center) and Catanzaro (in the South). The findings demonstrate that the obesity rate is 3.5% in the North, 6.1% in the Center and 8.8% in the South; these figures represent an increase both in the North and in the South. At the same time, the incidence of arterial hypertension has increased in respect to past years with 5.5% of the total study population diagnosed with hypertension over the 95 degrees percentile and 7.1% with borderline hypertension. Parental obesity has been demonstrated to be a key factor in determining the presence or level of obesity in their children. Obesity and arterial hypertension represent a worrisome departure point for a dangerous metabolic syndrome and hence require the full dedication of pediatricians in order to prevent the disease, with an urgent need for school interventions, support for a healthy diet and insistence on the necessity of adequate daily exercise.

  14. 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

  15. Cognitive outcomes in elderly high-risk patients after off-pump versus conventional coronary artery bypass grafting

    DEFF Research Database (Denmark)

    Jensen, Birte Ostergaard; Hughes, Pia; Rasmussen, Lars S

    2006-01-01

    It has been suggested that the risk of cerebral dysfunction is less with off-pump coronary artery bypass grafting (OPCAB) than with conventional coronary artery bypass grafting (CCAB). However, evidence for this statement is preliminary, and additional insight is needed.......It has been suggested that the risk of cerebral dysfunction is less with off-pump coronary artery bypass grafting (OPCAB) than with conventional coronary artery bypass grafting (CCAB). However, evidence for this statement is preliminary, and additional insight is needed....

  16. Nitrogen doped carbon derived from polyimide/multiwall carbon nanotube composites for high performance flexible all-solid-state supercapacitors

    Science.gov (United States)

    Kim, Dae Kyom; Kim, Nam Dong; Park, Seung-Keun; Seong, Kwang-dong; Hwang, Minsik; You, Nam-Ho; Piao, Yuanzhe

    2018-03-01

    Flexible all-solid-state supercapacitors are desirable as potential energy storage systems for wearable technologies. Herein, we synthesize aminophenyl multiwall carbon nanotube (AP-MWCNT) grafted polyimide precursor by in situ polymerization method as a nitrogen-doped carbon precursor. Flexible supercapacitor electrodes are fabricated via a coating of carbon precursor on carbon cloth surface and carbonization at high temperature directly. The as-obtained electrodes, which can be directly used without any binders or additives, can deliver a high specific capacitance of 333.4 F g-1 at 1 A g-1 (based on active material mass) and excellent cycle stability with 103% capacitance retention after 10,000 cycles in a three-electrode system. The flexible all-solid-state supercapacitor device exhibits a high volumetric capacitance of 3.88 F cm-3 at a current density of 0.02 mA cm-3. And also the device can deliver a maximum volumetric energy density of 0.50 mWh cm-3 and presents good cycling stability with 85.3% capacitance retention after 10,000 cycles. This device cell can not only show extraordinary mechanical flexibilities allowing folding, twisting, and rolling but also demonstrate remarkable stable electrochemical performances under their forms. This work provides a novel approach to obtain carbon textile-based flexible supercapacitors with high electrochemical performance and mechanical flexibility.

  17. Activated Biomass-derived Graphene-based Carbons for Supercapacitors with High Energy and Power Density.

    Science.gov (United States)

    Jung, SungHoon; Myung, Yusik; Kim, Bit Na; Kim, In Gyoo; You, In-Kyu; Kim, TaeYoung

    2018-01-30

    Here, we present a facile and low-cost method to produce hierarchically porous graphene-based carbons from a biomass source. Three-dimensional (3D) graphene-based carbons were produced through continuous sequential steps such as the formation and transformation of glucose-based polymers into 3D foam-like structures and their subsequent carbonization to form the corresponding macroporous carbons with thin graphene-based carbon walls of macropores and intersectional carbon skeletons. Physical and chemical activation was then performed on this carbon to create micro- and meso-pores, thereby producing hierarchically porous biomass-derived graphene-based carbons with a high Brunauer-Emmett-Teller specific surface area of 3,657 m 2  g -1 . Owing to its exceptionally high surface area, interconnected hierarchical pore networks, and a high degree of graphitization, this carbon exhibited a high specific capacitance of 175 F g -1 in ionic liquid electrolyte. A supercapacitor constructed with this carbon yielded a maximum energy density of 74 Wh kg -1 and a maximum power density of 408 kW kg -1 , based on the total mass of electrodes, which is comparable to those of the state-of-the-art graphene-based carbons. This approach holds promise for the low-cost and readily scalable production of high performance electrode materials for supercapacitors.

  18. 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

  19. High purity samarium oxide from mixed rare earth carbonates

    International Nuclear Information System (INIS)

    Queiroz, Carlos A. da S.; Seneda, Jose A.; Vasconcellos, Mari E. de; Pedreira Filho, Walter dos R.

    2013-01-01

    A simple and economical chemical process for the production of highly pure samarium oxides is discussed. The raw material, which was used in the form of rare earth carbonates was produced industrially from the chemical treatment of Brazilian monazite. Ion exchange chromatography was performed using a strong cationic resin that is typically employed in water treatment processes to fractionate rare earth elements (REE) without the use of retention ions. Under these conditions, 99.9% pure Sm 2 O 3 was eluted using the ammonium salt of ethylenediaminetetraacetic acid (EDTA) at a controlled pH. The EDTA-samarium complex was separated from EDTA and then precipitated as oxalate and fired to samarium oxide. Molecular absorption spectrophotometry was used to monitor the samarium content during the proposed process, and sector field inductively coupled plasma mass spectrometry was used to certify the purity of the samarium oxide. Typical samarium oxide obtained from the proposed procedure contained the following contaminants in micrograms per gram: Sc (20.90); Y (11.80); La (8.4); Ce (4.3); Pr (2.5); Nd (5.1); Eu (94); Gd (114); Tb (3.6); Dy (2.5), Ho (2.3); Er (3.0); Tm (2.3); Yb (38,2); Lu (25.6). The high-purity samarium oxides produced in the present study can be used as an alternative to imported products in research and development applications. (author)

  20. 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.

  1. High performance transistors via aligned polyfluorene-sorted carbon nanotubes

    Science.gov (United States)

    Brady, Gerald J.; Joo, Yongho; Singha Roy, Susmit; Gopalan, Padma; Arnold, Michael S.

    2014-02-01

    We evaluate the performance of exceptionally electronic-type sorted, semiconducting, aligned single-walled carbon nanotubes (s-SWCNTs) in field effect transistors (FETs). High on-conductance and high on/off conductance modulation are simultaneously achieved at channel lengths which are both shorter and longer than individual s-SWCNTs. The s-SWCNTs are isolated from heterogeneous mixtures using a polyfluorene-derivative as a selective agent and aligned on substrates via dose-controlled, floating evaporative self-assembly at densities of ˜50 s-SWCNTs μm-1. At a channel length of 9 μm the s-SWCNTs percolate to span the FET channel, and the on/off ratio and charge transport mobility are 2.2 × 107 and 46 cm2 V-1 s-1, respectively. At a channel length of 400 nm, a large fraction of the s-SWCNTs directly span the channel, and the on-conductance per width is 61 μS μm-1 and the on/off ratio is 4 × 105. These results are considerably better than previous solution-processed FETs, which have suffered from poor on/off ratio due to spurious metallic nanotubes that bridge the channel. 4071 individual and small bundles of s-SWCNTs are tested in 400 nm channel length FETs, and all show semiconducting behavior, demonstrating the high fidelity of polyfluorenes as selective agents and the promise of assembling s-SWCNTs from solution to create high performance semiconductor electronic devices.

  2. High performance transistors via aligned polyfluorene-sorted carbon nanotubes

    International Nuclear Information System (INIS)

    Brady, Gerald J.; Joo, Yongho; Singha Roy, Susmit; Gopalan, Padma; Arnold, Michael S.

    2014-01-01

    We evaluate the performance of exceptionally electronic-type sorted, semiconducting, aligned single-walled carbon nanotubes (s-SWCNTs) in field effect transistors (FETs). High on-conductance and high on/off conductance modulation are simultaneously achieved at channel lengths which are both shorter and longer than individual s-SWCNTs. The s-SWCNTs are isolated from heterogeneous mixtures using a polyfluorene-derivative as a selective agent and aligned on substrates via dose-controlled, floating evaporative self-assembly at densities of ∼50 s-SWCNTs μm −1 . At a channel length of 9 μm the s-SWCNTs percolate to span the FET channel, and the on/off ratio and charge transport mobility are 2.2 × 10 7 and 46 cm 2  V −1  s −1 , respectively. At a channel length of 400 nm, a large fraction of the s-SWCNTs directly span the channel, and the on-conductance per width is 61 μS μm −1 and the on/off ratio is 4 × 10 5 . These results are considerably better than previous solution-processed FETs, which have suffered from poor on/off ratio due to spurious metallic nanotubes that bridge the channel. 4071 individual and small bundles of s-SWCNTs are tested in 400 nm channel length FETs, and all show semiconducting behavior, demonstrating the high fidelity of polyfluorenes as selective agents and the promise of assembling s-SWCNTs from solution to create high performance semiconductor electronic devices

  3. High performance transistors via aligned polyfluorene-sorted carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Brady, Gerald J.; Joo, Yongho; Singha Roy, Susmit; Gopalan, Padma; Arnold, Michael S., E-mail: msarnold@wisc.edu [Department of Materials Science and Engineering, University of Wisconsin-Madison, 1509 University Avenue, Madison, Wisconsin 53706 (United States)

    2014-02-24

    We evaluate the performance of exceptionally electronic-type sorted, semiconducting, aligned single-walled carbon nanotubes (s-SWCNTs) in field effect transistors (FETs). High on-conductance and high on/off conductance modulation are simultaneously achieved at channel lengths which are both shorter and longer than individual s-SWCNTs. The s-SWCNTs are isolated from heterogeneous mixtures using a polyfluorene-derivative as a selective agent and aligned on substrates via dose-controlled, floating evaporative self-assembly at densities of ∼50 s-SWCNTs μm{sup −1}. At a channel length of 9 μm the s-SWCNTs percolate to span the FET channel, and the on/off ratio and charge transport mobility are 2.2 × 10{sup 7} and 46 cm{sup 2} V{sup −1} s{sup −1}, respectively. At a channel length of 400 nm, a large fraction of the s-SWCNTs directly span the channel, and the on-conductance per width is 61 μS μm{sup −1} and the on/off ratio is 4 × 10{sup 5}. These results are considerably better than previous solution-processed FETs, which have suffered from poor on/off ratio due to spurious metallic nanotubes that bridge the channel. 4071 individual and small bundles of s-SWCNTs are tested in 400 nm channel length FETs, and all show semiconducting behavior, demonstrating the high fidelity of polyfluorenes as selective agents and the promise of assembling s-SWCNTs from solution to create high performance semiconductor electronic devices.

  4. Effect of high surface area activated carbon on thermal degradation of jet fuel

    Energy Technology Data Exchange (ETDEWEB)

    Gergova, K.; Eser, S.; Arumugam, R.; Schobert, H.H. [Pennsylvania State Univ., University Park, PA (United States)

    1995-05-01

    Different solid carbons added to jet fuel during thermal stressing cause substantial changes in pyrolytic degradation reactions. Activated carbons, especially high surface area activated carbons were found to be very effective in suppressing solid deposition on metal reactor walls during stressing at high temperatures (425 and 450{degrees}C). The high surface area activated carbon PX-21 prevented solid deposition on reactor walls even after 5h at 450{degrees}C. The differences seen in the liquid product composition when activated carbon is added indicated that the carbon surfaces affect the degradation reactions. Thermal stressing experiments were carried out on commercial petroleum-derived JPTS jet fuel. We also used n-octane and n-dodecane as model compounds in order to simplify the study of the chemical changes which take place upon activated carbon addition. In separate experiments, the presence of a hydrogen donor, decalin, together with PX-21 was also studied.

  5. High biolability of ancient permafrost carbon upon thaw

    NARCIS (Netherlands)

    Vonk, J.E.; Mann, P.J.; Davydov, S.; Davydova, A.; Spencer, R.G.M.; Schade, J.; Sobczak, W.V.; Zimov, S.; Bulygina, E.; Eglinton, T.I.; Holmes, R.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

  6. 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

  7. 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...

  8. Effects of carbon dioxide level (PCO2) on the fibrinolytic activity (FA) of pulmonary artery endothelial cells (PAEC)

    International Nuclear Information System (INIS)

    Langleben, D.; Moroz, L.A.; Danes, D.

    1990-01-01

    Recovery from pulmonary thromboembolism depends on the rapidity and completeness of clot lysis. This involves endogenous fibrinolytic mechanisms, particularly the balance between plasminogen activators and inhibitors produced by endothelial cells. Hypocapnia is common in pulmonary embolism, however it is not known if endothelial fibrinolytic function is affected by PCO 2 . The authors therefore measured the FA in medium (MCDB-131, 0.5% albumin) conditioned for 20 hours in-vitro by exposure to confluent cultures of bovine proximal PAEC. During conditioning, cells were exposed to 5% CO 2 in air (PCO 2 - 36-40mm Hg, CONTROL), or various PCO 2 levels (30-55 mmHg, in air). FA of conditioned medium was determined by 125 I-fibrin solid phase assay, with addition of plasminogen (10 ug/ml). With PCO 2 levels ≤ 35 mmHg, FA in the conditioned medium was 5 to 18% higher than CONTROL FA. When PCO 2 was ≥ 45 mmHg, FA decreased 5 to 60% as compared to CONTROL FA. There was a significant negative linear relationship between PCO 2 and FA. Thus, PCO 2 level can affect PAEC mediated plasminogen activation. This finding may be relevant to in-vivo clearance of clots from pulmonary arteries

  9. Carbon isotope ratios of organic matter in Bering Sea settling particles. Extremely high remineralization of organic carbon derived from diatoms

    International Nuclear Information System (INIS)

    Yasuda, Saki; Akagi, Tasuku; Naraoka, Hiroshi; Kitajima, Fumio; Takahashi, Kozo

    2016-01-01

    The carbon isotope ratios of organic carbon in settling particles collected in the highly-diatom-productive Bering Sea were determined. Wet decomposition was employed to oxidize relatively fresh organic matter. The amount of unoxidised organic carbon in the residue following wet decomposition was negligible. The δ 13 C of organic carbon in the settling particles showed a clear relationship against SiO 2 /CaCO 3 ratio of settling particles: approximately -26‰ and -19‰ at lower and higher SiO 2 /CaCO 3 ratios, respectively. The δ 13 C values were largely interpreted in terms of mixing of two major plankton sources. Both δ 13 C and compositional data can be explained consistently only by assuming that more than 98% of diatomaceous organic matter decays and that organic matter derived from carbonate-shelled plankton may remain much less remineralized. A greater amount of diatom-derived organic matter is discovered to be trapped with the increase of SiO 2 /CaCO 3 ratio of the settling particles. The ratio of organic carbon to inorganic carbon, known as the rain ratio, therefore, tends to increase proportionally with the SiO 2 /CaCO 3 ratio under an extremely diatom-productive condition. (author)

  10. 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.

  11. Aligned Carbon Nanotubes for High-Performance Films and Composites

    Science.gov (United States)

    Zhang, Liwen

    Carbon nanotubes (CNTs) with extraordinary properties and thus many potential applications have been predicted to be the best reinforcements for the next-generation multifunctional composite materials. Difficulties exist in transferring the most use of the unprecedented properties of individual CNTs to macroscopic forms of CNT assemblies. Therefore, this thesis focuses on two main goals: 1) discussing the issues that influence the performance of bulk CNT products, and 2) fabricating high-performance dry CNT films and composite films with an understanding of the fundamental structure-property relationship in these materials. Dry CNT films were fabricated by a winding process using CNT arrays with heights of 230 mum, 300 im and 360 mum. The structures of the as-produced films, as well as their mechanical and electrical properties were examined in order to find out the effects of different CNT lengths. It was found that the shorter CNTs synthesized by shorter time in the CVD furnace exhibited less structural defects and amorphous carbon, resulting in more compact packing and better nanotube alignment when made into dry films, thus, having better mechanical and electrical performance. A novel microcombing approach was developed to mitigate the CNT waviness and alignment in the dry films, and ultrahigh mechanical properties and exceptional electrical performance were obtained. This method utilized a pair of sharp surgical blades with microsized features at the blade edges as micro-combs to, for the first time, disentangle and straighten the wavy CNTs in the dry-drawn CNT sheet at single-layer level. The as-combed CNT sheet exhibited high level of nanotube alignment and straightness, reduced structural defects, and enhanced nanotube packing density. The dry CNT films produced by microcombing had a very high Young's modulus of 172 GPa, excellent tensile strength of 3.2 GPa, and unprecedented electrical conductivity of 1.8x10 5 S/m, which were records for CNT films or

  12. High-carbon chromium steel resistance to small plastic deformation

    International Nuclear Information System (INIS)

    Gajduchenya, V.F.; Madyanov, S.A.; Apaev, B.A.; Kirillov, Yu.V.; Sokolov, L.D.

    1978-01-01

    The phase composition of a steel with 1.08% C and 2.1% Cr, and the variation in the level of microstresses in the matrix as related to the annealing temperature in the range of 400-600 deg C and in the applied compression stress were investigated. To study the phase composition, and chromium content in the α-solution and the carbide phases, magnetic, chemical, and X-ray spectrum analyses were carried out. The change in the level of microstresses was determined roentgenographically. During the stress relaxation test at temperatures of 20-180 deg C, the mechanism of plastic deformation near the yield point was investigated. It is shown that three dislocation mechanisms operate in high-carbon chromium steel under the conditions at hand: overcoming the Pierls-Nabarro barriers by the dislocations, overcoming the stress fields of coherent carbide particles by dislocations, and circumvention of second-phase particles by dislocations. The dependence of the realization of the different plastic deformation mechanisms on the number of carbide particles and the chromium concentration in the matrix was established. The thermally activated nature of the motion of the dislocations under conditions of stress relaxation at an elevated temperature is noted

  13. Tungsten and carbon surface change under high dose plasma exposure

    International Nuclear Information System (INIS)

    Martynenko, Y.V.; Khripunov, B.I.; Petrov, V.B.

    2009-01-01

    Study of surface composition dynamics has been made on the LENTA linear plasma simulator. Experiments have been made on tungsten and carbon materials subjected to steady-state plasma exposure. The achieved ion doses on the surface were 10 21 ion cm -2 . WL 10 tungsten containing 1% of La2O3 oxide and titanium-doped graphite RG-T were studied. The following experimental conditions were varied in these experiments: energy of ions, surface temperature, working gas. Irradiations of tungsten WL 10 were executed in deuterium plasma at low ion energies (about 20 eV) and at 200 eV for temperatures below 340 K. Graphite RG-T was exposed at 1300 K. Elevated surface temperature (about 1050K) was also characteristic of experiments on tungsten sample under nitrogen plasma impact (simulated inter-ELMs condition). Surface microstructure modification has been observed and surface composition changes were found on the materials showing influence of high dose plasma irradiations on element redistribution in the near surface layers. (author)

  14. High Temperature Resin/Carbon Nanotube Composite Fabrication

    Science.gov (United States)

    Ghose, Sayata; Watson, Kent A.; Sun, Keun J.; Criss, Jim M.; Siochi, Emilie J.; Connell, John W.

    2006-01-01

    For the purpose of incorporating multifunctionality into advanced composites, blends of phenylethynyl terminated imides-330 (PETI-330) and multi-walled carbon nanotubes (MWCNTs) were prepared, characterized and fabricated into moldings. PETI-330/MWCNT mixtures were prepared at concentrations ranging from 3 to 25 weight percent by dry mixing the components in a ball mill. The resulting powders were characterized for degree of mixing, thermal and rheological properties. Based on the characterization results, PETI-330/MWCNT samples were scaled up to approximately 300 g and used to fabricate moldings by injecting the mixtures at 260-280 deg C into a stainless steel tool followed by curing for 1 h at 371 deg C. The tool was designed to impart a degree of shear during the injection process in an attempt to achieve some alignment of the MWCNTs in the flow direction. Obtained moldings were subsequently characterized for thermal, mechanical, and electrical properties. The degree of dispersion and alignment of MWCNTs were investigated using high-resolution scanning electron microscopy. The preparation and preliminary characterization of PETI-330/MWCNT composites will be discussed.

  15. 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

  16. 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.

  17. High-performance carbon nanotube-implanted mesoporous carbon spheres for supercapacitors with low series resistance

    Energy Technology Data Exchange (ETDEWEB)

    Yi, Bin [College of Materials Science and Engineering, Hunan University, Changsha 410082 (China); Chen, Xiaohua, E-mail: hudacxh62@yahoo.com.cn [College of Materials Science and Engineering, Hunan University, Changsha 410082 (China); Guo, Kaimin [College of Physics and Electronic Science, Changsha University of Science and Technology (China); Xu, Longshan [Department of Mechanical Engineering, Xiamen University of Technology, Xiamen 361024 (China); Chen, Chuansheng [College of Physics and Electronic Science, Changsha University of Science and Technology (China); Yan, Haimei; Chen, Jianghua [College of Materials Science and Engineering, Hunan University, Changsha 410082 (China)

    2011-11-15

    Research highlights: {yields} CNTs-implanted porous carbon spheres are prepared by using gelatin as soft template. {yields} Homogeneously distributed CNTs form a well-develop network in carbon spheres. {yields} CNTs act as a reinforcing backbone assisting the formation of pore structure. {yields} CNTs improve electrical conductivity and specific capacitance of supercapacitor. -- Abstract: Carbon nanotube-implanted mesoporous carbon spheres were prepared by an easy polymerization-induced colloid aggregation method using gelatin as a soft template. Scanning electron microscopy, transmission electron microscopy and nitrogen adsorption-desorption measurements reveal that the materials are mesoporous carbon spheres, with a diameter of {approx}0.5-1.0 {mu}m, a specific surface area of 284 m{sup 2}/g and average pore size of 3.9 nm. Using the carbon nanotube-implanted mesoporous carbon spheres as electrode material for supercapacitors in an aqueous electrolyte solution, a low equivalent series resistance of 0.83 {Omega} cm{sup 2} and a maximum specific capacitance of 189 F/g with a measured power density of 8.7 kW/kg at energy density of 6.6 Wh/kg are obtained.

  18. Utilizing generalized autocalibrating partial parallel acquisition (GRAPPA) to achieve high-resolution contrast-enhanced MR angiography of hepatic artery: Initial experience in orthotopic liver transplantation candidates

    International Nuclear Information System (INIS)

    Xu Pengju; Yan Fuhua; Wang Jianhua; Lin Jiang; Fan Jia

    2007-01-01

    Objective: To evaluate feasibility of using GRAPPA to acquire high-resolution 3D contrast-enhanced MR angiography (CE-MRA) of hepatic artery and value of GRAPPA for displaying vessels anatomy. Materials and methods: High-resolution CE-MRA using GRAPPA was performed in 67 orthotopic liver transplantation recipient candidates. Signal intensity (SI) and relative SI, i.e., Cv-ro (vessel-to-liver contrast) of the aorta and the hepatic common artery (HCA), were measured. The SI and the relative SI were compared and analyzed using T-test. For purpose of qualitative evaluation, the vessel visualization quality and the order of depicted hepatic artery branches were evaluated by two radiologists independently and assessed by weighted kappa analysis. The depiction of hepatic arterial anatomy and variations was evaluated, and results were correlated with the findings in surgery. Results: The mean SI values were 283.29 ± 65.07 (mean ± S.D.) for aorta and 283.16 ± 64.07 for HCA, respectively. The mean relative SI values were 0.698 ± 0.09 for aorta and 0.696 ± 0.09 for HCA, respectively. Homogeneous enhancement between aorta and HCA was confirmed by statistically insignificant differences (p-values were 0.89 for mean SI values and 0.12 for mean relative SI values, respectively). The average score for vessel visualization ranged from good to excellent for different artery segments. Overall interobserver agreement in the visualization of different artery segments was excellent (kappa value > 0.80). The distal intrahepatic segmental arteries were well delineated for majority of patients with excellent interobserver agreement. Normal hepatic arterial anatomy was correctly demonstrated in 53 patients, and arterial anomalies were accurately detected on high-resolution MRA image of all 14 patients. Conclusion: High-resolution hepatic artery MRA acquired using GRAPPA in a reproducible manner excellently depicts and delineates small vessels and can be routinely used for evaluating

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

    Science.gov (United States)

    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.

  20. 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. Copyright © 2015 Elsevier Ltd. All rights reserved.

  1. Retinal artery occlusion during carotid artery stenting with distal embolic protection device.

    Science.gov (United States)

    Kohara, Kotaro; Ishikawa, Tatsuya; Kobayashi, Tomonori; Kawamata, Takakazu

    2018-01-01

    Retinal artery occlusion associated with carotid artery stenosis is well known. Although it can also occur at the time of carotid artery stenting, retinal artery occlusion via the collateral circulation of the external carotid artery is rare. We encountered two cases of retinal artery occlusion that were thought to be caused by an embolus from the external carotid artery during carotid artery stenting with a distal embolic protection device for the internal carotid artery. A 71-year-old man presented with central retinal artery occlusion after carotid artery stenting using the Carotid Guardwire PS and a 77-year-old man presented with branch retinal artery occlusion after carotid artery stenting using the FilterWire EZ. Because additional new cerebral ischaemic lesions were not detected in either case by postoperative diffusion-weighted magnetic resonance imaging, it was highly likely that the debris that caused retinal artery occlusion passed through not the internal carotid artery but collaterals to retinal arteries from the external carotid artery, which was not protected by a distal embolic protection device. It is suggested that a distal protection device for the internal carotid artery alone cannot prevent retinal artery embolisation during carotid artery stenting and protection of the external carotid artery is important to avoid retinal artery occlusion.

  2. 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

  3. High purity neodymium acetate from mixed rare earth carbonates

    International Nuclear Information System (INIS)

    Queiroz, Carlos A. da Silva; Rocha, Soraya M. Rizzo da; Vasconcellos, Mari E. de; Lobo, Raquel M.; Seneda, Jose A.; Pedreira, Walter dos R.

    2011-01-01

    A simple and economical chemical process for obtaining high purity neodymium acetate is discussed. The raw material in the form rare earth carbonate is produced industrially from the chemical treatment of Brazilian monazite. Ion exchange chromatography technique with a strong cationic resin, proper to water treatment, and without the use of retention ions was used for the fractionating of the rare earth elements (REE). In this way, it was possible to obtain 99.9% pure Nd 2 O 3 in yields greater than or equal 80%, with the elution of the REE using ammonium salt of ethylenediaminetetraacetic acid (EDTA) solution in pH controlled. The complex of EDTA-neodymium was transformed into neodymium oxide, which was subsequently dissolved in acetic acid to obtain the neodymium acetates. Molecular absorption spectrophotometry was used to monitor the neodymium content during the process and sector field inductively coupled plasma mass spectrometry was used to certify the purity of the neodymium acetates. The typical neodymium acetates obtained contain the followings contaminants in μg g -1 : Sc(5.1); Y (0.9); La (1.0); Ce (6.1); Pr (34,4); Sm (12.8); Eu (1.1); Gd (15.4); Tb (29.3); Dy (5.2), Ho(7.4); Er (14.6); Tm (0.3); Yb (2.5); Lu (1.0). The high purity neodymium acetates obtained from this procedure have been applied, replacing the imported product, in research and development area on rare earth catalysts. (author)

  4. High-resolution mapping of motor vehicle carbon dioxide emissions

    Science.gov (United States)

    McDonald, Brian C.; McBride, Zoe C.; Martin, Elliot W.; Harley, Robert A.

    2014-05-01

    A fuel-based inventory for vehicle emissions is presented for carbon dioxide (CO2) and mapped at various spatial resolutions (10 km, 4 km, 1 km, and 500 m) using fuel sales and traffic count data. The mapping is done separately for gasoline-powered vehicles and heavy-duty diesel trucks. Emission estimates from this study are compared with the Emissions Database for Global Atmospheric Research (EDGAR) and VULCAN. All three inventories agree at the national level within 5%. EDGAR uses road density as a surrogate to apportion vehicle emissions, which leads to 20-80% overestimates of on-road CO2 emissions in the largest U.S. cities. High-resolution emission maps are presented for Los Angeles, New York City, San Francisco-San Jose, Houston, and Dallas-Fort Worth. Sharp emission gradients that exist near major highways are not apparent when emissions are mapped at 10 km resolution. High CO2 emission fluxes over highways become apparent at grid resolutions of 1 km and finer. Temporal variations in vehicle emissions are characterized using extensive day- and time-specific traffic count data and are described over diurnal, day of week, and seasonal time scales. Clear differences are observed when comparing light- and heavy-duty vehicle traffic patterns and comparing urban and rural areas. Decadal emission trends were analyzed from 2000 to 2007 when traffic volumes were increasing and a more recent period (2007-2010) when traffic volumes declined due to recession. We found large nonuniform changes in on-road CO2 emissions over a period of 5 years, highlighting the importance of timely updates to motor vehicle emission inventories.

  5. Highly Efficient Procedure for the Synthesis of Fructone Fragrance Using a Novel Carbon based Acid

    Directory of Open Access Journals (Sweden)

    Xuezheng Liang

    2010-08-01

    Full Text Available The novel carbon based acid has been synthesized via one-step hydrothermal carbonization of furaldehyde and hydroxyethylsulfonic acid. A highly efficient procedure for the synthesis of fructone has been developed using the novel carbon based acid. The results showed that the catalyst possessed high activity for the reaction, giving a yield of over 95%. The advantages of high activity, stability, reusability and low cost for a simple synthesis procedure and wide applicability to various diols and β-keto esters make this novel carbon based acid one of the best choices for the reaction.

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

    Science.gov (United States)

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

    2009-07-01

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

  7. Growth of highly oriented carbon nanotubes by plasma-enhanced hot filament chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Z.P.; Xu, J.W.; Ren, Z.F.; Wang, J.H. [Materials Synthesis Laboratory, Departments of Physics and Chemistry, and Center for Advanced Photonic and Electronic Materials (CAPEM), State University of New York at Buffalo, Buffalo, New York 14260 (United States); Siegal, M.P.; Provencio, P.N. [Sandia National Laboratories, Albuquerque, New Mexico 87185-1421 (United States)

    1998-12-01

    Highly oriented, multiwalled carbon nanotubes were grown on polished polycrystalline and single crystal nickel substrates by plasma enhanced hot filament chemical vapor deposition at temperatures below 666 {degree}C. The carbon nanotubes range from 10 to 500 nm in diameter and 0.1 to 50 {mu}m in length depending on growth conditions. Acetylene is used as the carbon source for the growth of the carbon nanotubes and ammonia is used for dilution gas and catalysis. The plasma intensity, acetylene to ammonia gas ratio, and their flow rates, etc. affect the diameters and uniformity of the carbon nanotubes. {copyright} {ital 1998 American Institute of Physics.}

  8. 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

    2017-12-01

    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.

  9. Highly porous carbon with large electrochemical ion absorption capability for high-performance supercapacitors and ion capacitors

    Science.gov (United States)

    Wang, Shijie; Wang, Rutao; Zhang, Yabin; Zhang, Li

    2017-11-01

    Carbon-based supercapacitors have attracted extensive attention as the complement to batteries, owing to their durable lifespan and superiority in high-power-demand fields. However, their widespread use is limited by the low energy storage density; thus, a high-surface-area porous carbon is urgently needed. Herein, a highly porous carbon with a Brunauer-Emmett-Teller specific surface area up to 3643 m2 g-1 has been synthesized by chemical activation of papayas for the first time. This sp2-bonded porous carbon has a continuous three-dimensional network of highly curved, atom-thick walls that form narrow mesopores of 2 ˜ 5 nm in width, which can be systematically tailored with varied activation levels. Two-electrode symmetric supercapacitors constructed by this porous carbon achieve energy density of 8.1 Wh kg-1 in aqueous electrolyte and 65.5 Wh kg-1 in ionic-liquid electrolyte. Furthermore, half-cells (versus Li or Na metal) using this porous carbon as ion sorption cathodes yield high specific capacity, e.g., 51.0 and 39.3 mAh g-1 in Li+ and Na+ based organic electrolyte. These results underline the possibility of obtaining the porous carbon for high-performance carbon-based supercapacitors and ion capacitors in a readily scalable and economical way.

  10. Highly porous carbon with large electrochemical ion absorption capability for high-performance supercapacitors and ion capacitors.

    Science.gov (United States)

    Wang, Shijie; Wang, Rutao; Zhang, Yabin; Zhang, Li

    2017-11-03

    Carbon-based supercapacitors have attracted extensive attention as the complement to batteries, owing to their durable lifespan and superiority in high-power-demand fields. However, their widespread use is limited by the low energy storage density; thus, a high-surface-area porous carbon is urgently needed. Herein, a highly porous carbon with a Brunauer-Emmett-Teller specific surface area up to 3643 m 2 g -1 has been synthesized by chemical activation of papayas for the first time. This sp 2 -bonded porous carbon has a continuous three-dimensional network of highly curved, atom-thick walls that form narrow mesopores of 2 ∼ 5 nm in width, which can be systematically tailored with varied activation levels. Two-electrode symmetric supercapacitors constructed by this porous carbon achieve energy density of 8.1 Wh kg -1 in aqueous electrolyte and 65.5 Wh kg -1 in ionic-liquid electrolyte. Furthermore, half-cells (versus Li or Na metal) using this porous carbon as ion sorption cathodes yield high specific capacity, e.g., 51.0 and 39.3 mAh g -1 in Li + and Na + based organic electrolyte. These results underline the possibility of obtaining the porous carbon for high-performance carbon-based supercapacitors and ion capacitors in a readily scalable and economical way.

  11. High frequency electromechanical memory cells based on telescoping carbon nanotubes.

    Science.gov (United States)

    Popov, A M; Lozovik, Y E; Kulish, A S; Bichoutskaia, E

    2010-07-01

    A new method to increase the operational frequency of electromechanical memory cells based on the telescoping motion of multi-walled carbon nanotubes through the selection of the form of the switching voltage pulse is proposed. The relative motion of the walls of carbon nanotubes can be controlled through the shape of the interwall interaction energy surface. This allows the use of the memory cells in nonvolatile or volatile regime, depending on the structure of carbon nanotube. Simulations based on ab initio and semi-empirical calculations of the interwall interaction energies are used to estimate the switching voltage and the operational frequency of volatile cells with the electrodes made of carbon nanotubes. The lifetime of nonvolatile memory cells is also predicted.

  12. Design of Low Cost, Highly Adsorbent Activated Carbon Fibers

    National Research Council Canada - National Science Library

    Mangun, Christian

    2003-01-01

    .... EKOS has developed a novel activated carbon fiber - (ACF) that combines the low cost and durability of GAC with tailored pore size and pore surface chemistry for improved defense against chemical agents...

  13. Carbon dioxide concentrations are very high in developing oilseeds.

    Science.gov (United States)

    Goffman, Fernando D; Ruckle, Mike; Ohlrogge, John; Shachar-Hill, Yair

    2004-09-01

    A new method has been developed to rapidly determine the total inorganic carbon concentration (gaseous [CO2] + aqueous [CO(2)] + [HCO3-] + [CO3(2)-]) in developing seeds. Seeds are rapidly dissected and homogenized in 1 N HCl in gas-tight vials. The headspace gas is then analyzed by infrared gas analysis. Developing rapeseed (Brassica napus L.) and soybean [Glycine max (L.) Merr.] seeds were analyzed and found to have up to 40 and 12 mM total inorganic carbon, respectively. These concentrations are ca. 600-2000-fold higher than in ambient air or values reported for leaves. Carbon dioxide concentrations in rapeseed peaked during the stage of maximum oil synthesis and declined as seeds matured. The consequences for seed metabolism, physiology and carbon economy are discussed.

  14. The role of carbon in the breakaway oxidation of mild steel in high pressure carbon dioxide

    International Nuclear Information System (INIS)

    Surman, P.L.; Brown, A.M.

    1974-01-01

    The rate controlling step in the oxidation of iron and mild steel in CO 2 is the diffusion of iron across the inner of two layers of magnetite scale. Cation diffusion is directed towards available oxidant and hence tends to produce fresh oxide in freely available space. The initial oxidation process is thus protective and stress-free. As oxidation proceeds the gaseous reaction product, carbon monoxide, tends to accumulate at the oxide/metal interface. Eventually this leads to simultaneous carbon deposition and oxide formation. This carbon contamination allows oxidant access to oxide crystallite 'jacking points', and hence volume expansion and stressed breakaway corrosion can occur. Experiments designed to simulate the promotion, propagation and healing of breakaway oxidation and to define the conditions for carbon deposition are reported. (author)

  15. The role of central venous oxygen saturation, blood lactate, and central venous-to-arterial carbon dioxide partial pressure difference as a goal and prognosis of sepsis treatment.

    Science.gov (United States)

    Wittayachamnankul, Borwon; Chentanakij, Boriboon; Sruamsiri, Kamphee; Chattipakorn, Nipon

    2016-12-01

    The current practice in treatment of severe sepsis and septic shock is to ensure adequate oxygenation and perfusion in patients, along with prompt administration of antibiotics, within 6 hours from diagnosis, which is considered the "golden hour" for the patients. One of the goals of treatment is to restore normal tissue perfusion. With this goal in mind, some parameters have been used to determine the success of treatment and mortality rate; however, none has been proven to be the best predictor of mortality rate in sepsis patients. Despite growing evidence regarding the prognostic indicators for mortality in sepsis patients, inconsistent reports exist. This review comprehensively summarizes the reports regarding the frequently used parameters in sepsis including central venous oxygen saturation, blood lactate, and central venous-to-arterial carbon dioxide partial pressure difference, as prognostic indicators for clinical outcomes in sepsis patients. Moreover, consistent findings and inconsistent reports for their pathophysiology and the potential mechanisms for their use as well as their limitations in sepsis patients are presented and discussed. Finally, a schematic strategy for potential management and benefits in sepsis patients is proposed based upon these current available data. There is currently no ideal biomarker that can indicate prognosis, predict progression of the disease, and guide treatment in sepsis. Further studies are needed to be carried out to identify the ideal biomarker that has all the desired properties. Copyright © 2016 Elsevier Inc. All rights reserved.

  16. Combining central venous-to-arterial partial pressure of carbon dioxide difference and central venous oxygen saturation to guide resuscitation in septic shock.

    Science.gov (United States)

    Du, Wei; Liu, Da-Wei; Wang, Xiao-Ting; Long, Yun; Chai, Wen-Zhao; Zhou, Xiang; Rui, Xi

    2013-12-01

    Central venous oxygen saturation (Scvo2) is a useful therapeutic target when treating septic shock. We hypothesized that combining Scvo2 and central venous-to-arterial partial pressure of carbon dioxide difference (△Pco2) may provide additional information about survival. We performed a retrospective analysis of 172 patients treated for septic shock. All patients were treated using goal-directed therapy to achieve Scvo2 ≥ 70%. After 6 hours of treatment, we divided patients into 4 groups based on Scvo2 (<70% or ≥ 70%) and △Pco2 (<6 mm Hg or ≥ 6 mm Hg). Overall, 28-day mortality was 35.5%. For patients in whom the Scvo2 target was not achieved at 6 hours, mortality was 50.0%, compared with 29.5% in those in whom Scvo2 exceeded 70% (P = .009). In patients with Scvo2 ≥ 70%, mortality was lower if △Pco2 was <6 mm Hg than if △Pco2 was ≥ 6 mm Hg (56.1% vs 16.1%, respectively; P < .001) and 6-hour lactate clearance was superior (0.01 ± 0.61 vs 0.21 ± 0.31, respectively; P = .016). The combination of Scvo2 and △Pco2 appears to predict outcome in critically ill patients resuscitated from septic shock better than Scvo2 alone. Patients who meet both targets appear to clear lactate more efficiently. © 2013.

  17. NOVEL CERAMIC MEMBRANE FOR HIGH TEMPERATURE CARBON DIOXIDE SEPARATION

    International Nuclear Information System (INIS)

    Ida, Jun-ichi; Yang, Zhaohui; Lin, Jerry Y.S.

    2002-01-01

    A new CO 2 semi-permeable dense inorganic membrane consisting of a porous metal phase and molten carbonate was proposed. A simple direct infiltration method was used to synthesize the metal-carbonate dual-phase membrane. Hermetic (gas-tight) dual phase membrane was successfully obtained. Permeation data showed that nitrogen or helium is not permeable through the membrane (only CO 2 , with O 2 can permeate through the membrane based on transport mechanism)

  18. 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...... adsorption of [C2C1MIM][Cl] on the inner sidewalls of 1-3 nm carbon nanotubes....

  19. Liver cirrhosis and arterial hypertension

    DEFF Research Database (Denmark)

    Henriksen, Jens Henrik; Møller, Søren

    2006-01-01

    blood pressure. This review considers the alterations in systemic hemodynamics in patients with cirrhosis in relation to essential hypertension and arterial hypertension of the renal origin. Subjects with arterial hypertension (essential, secondary) may become normotensive during the development...... of cirrhosis, and arterial hypertension is rarely manifested in patients with cirrhosis, even in cases with renovascular disease and high circulating renin activity. There is much dispute as to the understanding of homoeostatic regulation in cirrhotic patients with manifest arterial hypertension. This most...

  20. Low-carbohydrate, high-protein, high-fat diet alters small peripheral artery reactivity in metabolic syndrome patients.

    Science.gov (United States)

    Merino, Jordi; Kones, Richard; Ferré, Raimon; Plana, Núria; Girona, Josefa; Aragonés, Gemma; Ibarretxe, Daiana; Heras, Mercedes; Masana, Luis

    2014-01-01

    Low carbohydrate diets have become increasingly popular for weight loss. Although they may improve some metabolic markers, particularly in type 2 diabetes mellitus (T2D) or metabolic syndrome (MS), their net effect on vascular function remains unclear. Evaluate the relation between dietary macronutrient composition and the small artery reactive hyperaemia index (saRHI), a marker of small artery vascular function, in a cohort of MS patients. This cross-sectional study included 160 MS patients. Diet was evaluated by a 3-day food-intake register and reduced to a novel low-carbohydrate diet score (LCDS). Physical examination, demographic, biochemical and anthropometry parameters were recorded, and saRHI was measured in each patient. Individuals in the lowest LCDS quartile (Q1; 45% carbohydrate, 19% protein, 31% fat) had higher saRHI values than those in the top quartile (Q4; 30% carbohydrate, 25% protein, 43% fat) (1.84±0.42 vs. 1.55±0.25, P=.012). These results were similar in T2D patients (Q1=1.779±0.311 vs. Q4=1.618±0.352, P=.011) and also in all of the MS components, except for low HDLc. Multivariate analysis demonstrated that individuals in the highest LCDS quartile, that is, consuming less carbohydrates, had a significantly negative coefficient of saRHI which was independent of confounders (HR: -0.747; 95%CI: 0.201, 0.882; P=.029). These data suggest that a dietary pattern characterized by a low amount of carbohydrate, but reciprocally higher amounts of fat and protein, is associated with poorer vascular reactivity in patients with MS and T2D. Copyright © 2013 Sociedad Española de Arteriosclerosis. Published by Elsevier España. All rights reserved.

  1. 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

  2. Highly ordered macroporous woody biochar with ultra-high carbon content as supercapacitor electrodes

    International Nuclear Information System (INIS)

    Jiang, Junhua; Zhang, Lei; Wang, Xinying; Holm, Nancy; Rajagopalan, Kishore; Chen, Fanglin; Ma, Shuguo

    2013-01-01

    Woody biochar monolith with ultra-high carbon content and highly ordered macropores has been prepared via one-pot pyrolysis and carbonization of red cedar wood at 750 °C without the need of post-treatment. Energy-dispersive spectroscope (EDX) and scanning electron microscope (SEM) studies show that the original biochar has a carbon content of 98 wt% with oxygen as the only detectable impurity and highly ordered macroporous texture characterized by alternating regular macroporous regions and narrow porous regions. Moreover, the hierarchically porous biochar monolith has a high BET specific surface area of approximately 400 m 2 g −1 . We have studied the monolith material as supercapacitor electrodes under acidic environment using electrochemical and surface characterization techniques. Electrochemical measurements show that the original biochar electrodes have a potential window of about 1.3 V and exhibit typical rectangular-shape voltammetric responses and fast charging–discharging behavior with a gravimetric capacitance of about 14 F g −1 . Simple activation of biochar in diluted nitric acid at room temperature leads to 7 times increase in the capacitance (115 F g −1 ). Because the HNO 3 -activation slightly decreases rather than increases the BET surface area of the biochar, an increase in the coverage of surface oxygen groups is the most likely origin of the substantial capacitance improvement. This is supported by EDX, X-ray photoelectron spectroscopy (XPS), and Raman measurements. Preliminary life-time studies show that biochar supercapacitors using the original and HNO 3 -activated electrodes are stable over 5000 cycles without performance decays. These facts indicate that the use of woody biochar is promising for its low cost and it can be a good performance electrode with low environmental impacts for supercapacitor applications

  3. High Mortality without ESCAPE: The Registry of Heart Failure Patients Receiving Pulmonary Artery Catheters without Randomization

    Science.gov (United States)

    Allen, Larry A.; Rogers, Joseph G.; Warnica, J. Wayne; DiSalvo, Thomas G.; Tasissa, Gudaye; Binanay, Cynthia; O’Connor, Christopher M.; Califf, Robert M.; Leier, Carl V.; Shah, Monica R.; Stevenson, Lynne W.

    2008-01-01

    Background In ESCAPE, there was no difference in days alive and out of the hospital for patients with decompensated heart failure (HF) randomly assigned to therapy guided by pulmonary artery catheter (PAC) plus clinical assessment versus clinical assessment alone. The external validity of these findings is debated. Methods and Results ESCAPE sites enrolled 439 patients receiving PAC without randomization in a prospective registry. Baseline characteristics, pertinent trial exclusion criteria, reasons for PAC use, hemodynamics, and complications were collected. Survival was determined from the National Death Index and the Alberta Registry. On average, registry patients had lower blood pressure, worse renal function, less neurohormonal antagonist therapy, and higher use of intravenous inotropes as compared with trial patients. Although clinical assessment anticipated less volume overload and greater hypoperfusion among the registry population, measured filling pressures were similarly elevated in the registry and trial, while measured perfusion was slightly higher among registry patients. Registry patients had longer hospitalization (13 vs. 6 days, p <0.001) and higher 6-month mortality (34% vs. 20%, p < 0.001) than trial patients. Conclusions The decision to use PAC without randomization identified a population with higher disease severity and risk of mortality. This prospective registry highlights the complex context of patient selection for randomized trials. PMID:18926438

  4. 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 th, pBP ≥90th, pBP th. In each group, haemodynamic and vascular parameters were compared for subgroups defined considering the level of the remaining 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.

  5. Electrorefining of High Carbon Ferromanganese in Molten Salts to Produce Pure Ferromanganese

    Directory of Open Access Journals (Sweden)

    Xiao S. J.

    2017-09-01

    Full Text Available High carbon ferromanganese is used as a starting material to prepare pure ferromanganese by electrorefining in molten salts. High carbon ferromanganese was applied as the anode, molybdenum was the cathode and Ag/AgCl was the reference electrode. The anodic dissolution was investigated by linear polarization in molten NaCl-KCl system. Then potentiostatic electrolysis was carried out to produce pure ferromanganese from high carbon ferromanganese. The cathodic product was determined to be a mixture of manganese and iron by x-ray diffraction (XRD. The content of carbon in the product was analyzed by carbon and sulfur analyzer. The post-electrolysis anode was characterized by scanning electron microscope (SEM. The mechanism of the anode dissolution and the distribution of the main impurity of carbon and silicon after electrolysis were discussed.

  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

    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. High-dose statin therapy in patients with stable coronary artery disease: treating the right patients based on individualized prediction of treatment effect

    NARCIS (Netherlands)

    Dorresteijn, Johannes A. N.; Boekholdt, S. Matthijs; van der Graaf, Yolanda; Kastelein, John J. P.; LaRosa, John C.; Pedersen, Terje R.; Demicco, David A.; Ridker, Paul M.; Cook, Nancy R.; Visseren, Frank L. J.

    2013-01-01

    Clinicians need to identify coronary artery disease patients for whom the benefits of high-dose versus usual-dose statin therapy outweigh potential harm. We therefore aimed to develop and validate a model for prediction of the incremental treatment effect of high-dose statins for individual patients

  8. General corrosion of carbon steels in high temperature water

    International Nuclear Information System (INIS)

    Gras, J.M.

    1994-04-01

    This short paper seeks to provide a summary of the main knowledge about the general corrosion of carbon steels in high temperature water. In pure water or slightly alkaline deaerated water, steels develop a protective coating of magnetite in a double layer (Potter and Mann oxide) or a single layer (Bloom oxide). The morphology of the oxide layer and the kinetics of corrosion depend on the test parameters controlling the solubility of iron. The parameters exercising the greatest influence are partial hydrogen pressure and mass transfer: hydrogen favours the solubilization of the magnetite; the entrainment of the dissolved iron prevents a redeposition of magnetite on the surface of the steel. Cubic or parabolic in static conditions, the kinetics of corrosion tends to be linear in dynamic conditions. In dynamic operation, corrosion is at least one order of magnitude lower in water with a pH of 10 than in pure water with a pH of 7. The activation energy of corrosion is 130 kJ/mol (31 kcal/mol). This results in the doubling of corrosion at around 300 deg C for a temperature increase of 15 deg C. Present in small quantities (100-200 ppb), oxygen decreases general corrosion but increases the risk of pitting corrosion - even for a low chloride content - and stress corrosion cracking or corrosion-fatigue. The steel composition has probably an influence on the kinetics of corrosion in dynamic conditions; further work would be required to clarify the effect of some residual elements. (author). 31 refs., 9 figs., 2 tabs

  9. Relationships between high-sensitive C-reactive protein and markers of arterial stiffness in hypertensive patients. Differences by sex

    Directory of Open Access Journals (Sweden)

    Gomez-Marcos Manuel A

    2012-06-01

    Full Text Available Abstract Background The present study was designed to evaluate the relationship between high-sensitivity C-reactive protein (hs-CRP and arterial stiffness according to sex in patients with arterial hypertension. Methods A case-series study was carried out in 258 hypertensive patients without antecedents of cardiovascular disease or diabetes mellitus. Nephelometry was used to determine hs-CRP. Office or clinical and home blood pressures were measured with a validated OMRON model M10 sphygmomanometer. Ambulatory blood pressure monitoring was performed with the SpaceLabs 90207 system. Pulse wave velocity (PWV and central and peripheral augmentation index (AIx were measured with the SphygmoCor system, and a Sonosite Micromax ultrasound unit was used for automatic measurements of carotid intima-media thickness (IMT. Ambulatory arterial stiffness index and home arterial stiffness index were calculated as “1-slope” from the within-person regression analysis of diastolic-on-systolic ambulatory blood pressure. Results Central and peripheral AIx were greater in women than in men: 35.31 ± 9.95 vs 26.59 ± 11.45 and 102.06 ± 20.47 vs 85.97 ± 19.13, respectively. IMT was greater in men (0.73 ± 0.13 vs 0.69 ± 0.10. hs-CRP was positively correlated to IMT (r = 0.261, maximum (r = 0.290 and to peripheral AIx (r = 0.166 in men, and to PWV in both men (r = 0.280 and women (r = 0.250. In women, hs-CRP was negatively correlated to central AIx (r = −0.222. For each unit increase in hs-CRP, carotid IMT would increase 0.05 mm in men, and PWV would increase 0.07 m/sec in men and 0.08 m/sec in women, while central AIx would decrease 2.5 units in women. In the multiple linear regression analysis, hs-CRP explained 10.2% and 6.7% of PWV variability in women and men, respectively, 8.4% of carotid IMT variability in men, and 4.9% of central AIx variability in women. Conclusions After adjusting for age, other

  10. Effect of alkali metal content of carbon on retention of iodine at high temperatures

    International Nuclear Information System (INIS)

    Evans, A.G.

    1975-01-01

    Activated carbon for filters in reactor confinement systems is intentionally impregnated with iodine salts to enhance the removal of radioiodine from air streams containing organic iodides. When a variety of commercial impregnated carbons were evaluated for iodine retention at elevated temperatures (4 hours at 180 0 C), wide variations in iodine penetration were observed. The alkali metal and iodine content of carbon samples was determined by neutron activation analysis, and a strong correlation was shown between the atom ratio of iodine to alkali metals in the carbons and the high-temperature retention performance. Carbons containing excess alkali (especially potassium) have iodine penetration values 10 to 100 times lower than carbons containing excess iodine. Both low I/K ratios and high pH values were shown essential to high efficiency iodine retention; therefore, conversion of elemental iodine to ionic iodine is the basic reaction mechanism. The natural high K + content and high pH coconut carbons make coconut the preferred natural base material for nuclear air cleaning applications. Studies show, however, that treatment of low potassium carbons with a mixture of KOH and I 2 may produce a product equal to or better than I 2 -impregnated coconut carbons at a lower cost. (U.S.)

  11. Arterial to end-tidal carbon dioxide tension difference (CO2 gap) as a prognostic marker for adverse outcomes in emergency department patients presenting with suspected sepsis.

    Science.gov (United States)

    Shetty, Amith; Sparenberg, Sebastian; Adams, Kristian; Selvedran, Selwyn; Tang, Benjamin; Hanna, Kim; Iredell, Jonathan

    2018-05-13

    The arterial to end-tidal carbon dioxide tension difference (CO 2 gap) correlates with physiologic dead space. The prognostic value of increased CO 2 gap in trauma and respiratory distress patients is documented. Transpulmonary arteriovenous shunting is identified as a predictor of mortality in non-pulmonary sepsis. We set out to investigate the prognostic value of the CO 2 gap in a pilot study of patients with suspected sepsis from non-respiratory causes. Patients presenting to tertiary Australian ED with suspected sepsis (n = 215) underwent near-simultaneous end-tidal carbon dioxide and partial pressure of carbon dioxide measurements. We investigated the correlation of CO 2 gap levels with the primary outcome of in-hospital mortality (IHM) and secondary outcomes of sepsis (ΔSOFA ≥2) and IHM and/or intensive care unit stay ≥72 h (IHM/ICU72h) in patients with sepsis because of non-respiratory causes. Among patients included in the analysis (n = 165), the CO 2 gap showed modest positive correlation with qSOFA (ρ = 0.39) and weak positive correlation with SOFA scores (ρ = 0.29) (both P < 0.01). The CO 2 gap had modest predictive value for primary outcome (IHM), area under receiver operating curve (AUROC 0.85, 95% confidence interval [CI] 0.78-0.90) and IHM/ICU72h outcome (AUROC 0.80, 95% CI 0.73-0.86), but lower predictive value for sepsis outcome (AUROC 0.64, 95% CI 0.55-0.71) (all P < 0.001). We report modest test performance for primary outcome at CO 2 gap ≥5 and ≥10 mmHg cut-offs. In this pilot study of patients with suspected sepsis from non-respiratory causes, an increased CO 2 gap demonstrates value in risk stratification and needs to be further evaluated and compared to other existent biomarkers. © 2018 Australasian College for Emergency Medicine & Australasian Society for Emergency Medicine.

  12. Pulse contour analysis of arterial waveform in a high fidelity human patient simulator.

    Science.gov (United States)

    Persona, Paolo; Saraceni, Elisabetta; Facchin, Francesca; Petranzan, Enrico; Parotto, Matteo; Baratto, Fabio; Ori, Carlo; Rossi, Sandra

    2017-10-03

    The measurement of cardiac output (CO) may be useful to improve the assessment of hemodynamics during simulated scenarios. The purpose of this study was to evaluate the feasibility of introducing an uncalibrated pulse contour device (MostCare, Vytech, Vygon, Padova, Italy) into the simulation environment. MostCare device was plugged to a clinical monitor and connected to the METI human patient simulator (HPS) to obtain a continuous arterial waveform analysis and CO calculation. In six different simulated clinical scenarios (baseline, ventricular failure, vasoplegic shock, hypertensive crisis, hypovolemic shock and aortic stenosis), the HPS-CO and the MostCare-CO were simultaneously recorded. The level of concordance between the two methods was assessed by the Bland and Altman analysis. 150-paired CO values were obtained. The HPS-CO values ranged from 2.3 to 6.6 L min -1 and the MostCare-CO values from 2.8 to 6.4 L min -1 . The mean difference between HPS-CO and MostCare-CO was - 0.3 L min -1 and the limits of agreement were - 1.5 and 0.9 L min -1 . The percentage of error was 23%. A good correlation between HPS-CO and MostCare-CO was observed in each scenario of the study (r = 0.88). Although MostCare-CO tended to underestimate the CO over the study period, good agreements were found between the two methods. Therefore, a pulse contour device can be integrated into the simulation environment, offering the opportunity to create new simulated clinical settings.

  13. 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.

  14. Highly conductive porous Na-embedded carbon nanowalls for high-performance capacitive deionization

    Science.gov (United States)

    Chang, Liang; Hu, Yun Hang

    2018-05-01

    Highly conductive porous Na-embedded carbon nanowalls (Na@C), which were recently invented, have exhibited excellent performance for dye-sensitized solar cells and electric double-layer capacitors. In this work, Na@C was demonstrated as an excellent electrode material for capacitive deionization (CDI). In a three-electrode configuration system, the specific capacity of the Na@C electrodes can achieve 306.4 F/g at current density of 0.2 A/g in 1 M NaCl, which is higher than that (235.2 F/g) of activated carbon (AC) electrodes. Furthermore, a high electrosorption capacity of 8.75 mg g-1 in 100 mg/L NaCl was obtained with the Na@C electrodes in a batch-mode capacitive deionization cell. It exceeds the electrosorption capacity (4.08 mg g-1) of AC electrodes. The Na@C electrode also showed a promising cycle stability. The excellent performance of Na@C electrode for capacitive deionization (CDI) can be attributed to its high electrical conductivity and large accessible surface area.

  15. Hierarchically porous carbon with high-speed ion transport channels for high performance supercapacitors

    Science.gov (United States)

    Lu, Haoyuan; Li, Qingwei; Guo, Jianhui; Song, Aixin; Gong, Chunhong; Zhang, Jiwei; Zhang, Jingwei

    2018-01-01

    Hierarchically porous carbons (HPC) are considered as promising electrode materials for supercapacitors, due to their outstanding charge/discharge cycling stabilities and high power densities. However, HPC possess a relatively low ion diffusion rate inside the materials, which challenges their application for high performance supercapacitor. Thus tunnel-shaped carbon pores with a size of tens of nanometers were constructed by inducing the self-assembly of lithocholic acid with ammonium chloride, thereby providing high-speed channels for internal ion diffusion. The as-formed one-dimensional pores are beneficial to the activation process by KOH, providing a large specific surface area, and then facilitate rapid transport of electrolyte ions from macropores to the microporous surfaces. Therefore, the HPC achieve an outstanding gravimetric capacitance of 284 F g-1 at a current density of 0.1 A g-1 and a remarkable capacity retention of 64.8% when the current density increases by 1000 times to 100 A g-1.

  16. Hardness of high-pressure high-temperature treated single-walled carbon nanotubes

    International Nuclear Information System (INIS)

    Kawasaki, S.; Nojima, Y.; Yokomae, T.; Okino, F.; Touhara, H.

    2007-01-01

    We have performed high-pressure high-temperature (HPHT) treatments of high quality single-walled carbon nanotubes (SWCNTs) over a wide pressure-temperature range up to 13 GPa-873 K and have investigated the hardness of the HPHT-treated SWCNTs using a nanoindentation technique. It was found that the hardness of the SWCNTs treated at pressures greater than 11 GPa and at temperatures higher than 773 K is about 10 times greater than that of the SWCNTs treated at low temperature. It was also found that the hardness change of the SWCNTs is related to the structural change by the HPHT treatments which was based on synchrotron X-ray diffraction measurements

  17. Preparation of activated carbon from western Canadian high rank coals

    Energy Technology Data Exchange (ETDEWEB)

    Kovacik, G.; Wong, B.; Furimsky, E. [Alberta Research Council, Devon, AB (Canada). Coal and Hydrocarbon Processing Dept.

    1995-01-01

    Partial steam gasification of Mt. Klappan anthracite and Cascade semianthracite with char conversion greater than 60%, produced activated carbons with surface areas greater than 1000 m{sup 2}/g. The pore structures of the activated carbons were predominantly microporous and mesoporous. The proportions of macropores were of the order of 2%. Fuel gas produced during steam activation of chars contained predominantly combustible gases i.e. 45-55% H{sub 2} and 30-40% CO whereas the amount of CO{sub 2} ranged between 5 and 15%. Correlations of char conversion with operating parameters and surface areas were developed and used to predict the activation process. Selected samples of activated carbons were characterized for the water and wastewater treatment as well as for gold recovery. 7 refs., 3 figs., 7 tabs.

  18. 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.

  19. Anomalous origin of the coronary artery from the wrong coronary sinus evaluated with computed tomography: ''High-risk'' anatomy and its clinical relevance

    International Nuclear Information System (INIS)

    Krupinski, Maciej; Urbanczyk-Zawadzka, Malgorzata; Laskowicz, Bartosz; Irzyk, Malgorzata; Banys, Robert; Klimeczek, Piotr; Gruszczynska, Katarzyna; Baron, Jan

    2014-01-01

    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.)

  20. High-resolution computed tomography evaluation of the bronchial lumen to vertebral body diameter and pulmonary artery to vertebral body diameter ratios in anesthetized ventilated normal cats.

    Science.gov (United States)

    Lee-Fowler, Tekla M; Cole, Robert C; Dillon, A Ray; Tillson, D Michael; Garbarino, Rachel; Barney, Sharron

    2017-10-01

    Objectives Bronchial lumen to pulmonary artery diameter (BA) ratio has been utilized to investigate pulmonary pathology on high-resolution CT images. Diseases affecting both the bronchi and pulmonary arteries render the BA ratio less useful. The purpose of the study was to establish bronchial lumen diameter to vertebral body diameter (BV) and pulmonary artery diameter to vertebral body diameter (AV) ratios in normal cats. Methods Using high-resolution CT images, 16 sets of measurements (sixth thoracic vertebral body [mid-body], each lobar bronchi and companion pulmonary artery diameter) were acquired from young adult female cats and 41 sets from pubertal female cats. Results Young adult and pubertal cat BV ratios were not statistically different from each other in any lung lobe. Significant differences between individual lung lobe BV ratios were noted on combined age group analysis. Caudal lung lobe AV ratios were significantly different between young adult and pubertal cats. All other lung lobe AV ratios were not significantly different. Caudal lung lobe AV ratios were significantly different from all other lung lobes but not from each other in both the young adult and pubertal cats. Conclusions and relevance BV ratio reference intervals determined for individual lung lobes could be applied to both young adult and pubertal cats. Separate AV ratios for individual lung lobes would be required for young adult and pubertal cats. These ratios should allow more accurate evaluation of cats with concurrent bronchial and pulmonary arterial disease.

  1. Highly aligned carbon nanotube arrays fabricated by bias sputtering

    International Nuclear Information System (INIS)

    Hayashi, Nobuyuki; Honda, Shin-ichi; Tsuji, Keita; Lee, Kuei-Yi; Ikuno, Takashi; Fujimoto, Keiichi; Ohkura, Shigeharu; Katayama, Mitsuhiro; Oura, Kenjiro; Hirao, Takashi

    2003-01-01

    Vertically aligned carbon nanotube (CNT) arrays have been successfully grown on Si substrates by dc bias sputtering. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) observations revealed that the resultant arrays consisted of dense CNTs with diameters of 40-60 nm and lengths of 300-400 nm. The CNTs were found to have a bamboo-like structure at the end of which metallic nanoparticle was formed, indicating tip growth mechanism. The energy enhancement of carbon particles is a key factor for synthesis of CNTs using dc bias sputtering system

  2. 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

  3. 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...... 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. CONCLUSION: In giraffes, GFR, ERPF and RI appear much lower than expected based...... adaption in the giraffe kidney allows normal for size renal haemodynamics and glomerular filtration rate (GFR) despite a MAP double that of other mammals. METHODS: Fourteen anaesthetized giraffes were instrumented with vascular and bladder catheters to measure glomerular filtration rate (GFR) and effective...

  4. 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...... of pyrolysed carbon films with increased film resistance due to oxidation during storage....

  5. N-Doped carbon spheres with hierarchical micropore-nanosheet networks for high performance supercapacitors.

    Science.gov (United States)

    Wang, Shoupei; Zhang, Jianan; Shang, Pei; Li, Yuanyuan; Chen, Zhimin; Xu, Qun

    2014-10-18

    N-doped carbon spheres with hierarchical micropore-nanosheet networks (HPSCSs) were facilely fabricated by a one-step carbonization and activation process of N containing polymer spheres by KOH. With the synergy effect of the multiple structures, HPSCSs exhibit a very high specific capacitance of 407.9 F g(-1) at 1 mV s(-1) (1.2 times higher than that of porous carbon spheres) and a robust cycling stability for supercapacitors.

  6. From carbon nanostructures to high-performance sorbents for chromatographic separation and preconcentration

    International Nuclear Information System (INIS)

    Postnov, V N; Rodinkov, O V; Moskvin, L N; Novikov, A G; Bugaichenko, A S; Krokhina, O A

    2016-01-01

    Information on carbon nanostructures (fullerenes, nanotubes, graphene, nanodiamond and nanodispersed active carbon) used to develop high-performance sorbents of organics and heavy metal ions from aqueous solutions is collected and analyzed. The advantages in the synthesis of hybrid carbon nanostructures and the possibilities of surface modification of these systems in order to carry out fast sorption pre-concentration are considered. Prospects for application of these materials in sorption technologies and analytical chemistry are discussed. The bibliography includes 364 references

  7. 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.

  8. Highly Loaded Carbon Black Supported Pt Catalysts for Fuel Cells

    Czech Academy of Sciences Publication Activity Database

    Kaluža, Luděk; Larsen, M.J.; Zdražil, Miroslav; Gulková, Daniela; Vít, Zdeněk; Šolcová, Olga; Soukup, Karel; Koštejn, Martin; Bonde, J.L.; Maixnerová, Lucie; Odgaard, M.

    2015-01-01

    Roč. 256, NOV 1 (2015), s. 375-383 ISSN 0920-5861 R&D Projects: GA MŠk(CZ) 7HX13003 EU Projects: European Commission(XE) 303466 - IMMEDIATE Institutional support: RVO:67985858 Keywords : carbon black * fuell cell * electrocatalyst Subject RIV: CI - Industrial Chemistry , Chemical Engineering Impact factor: 4.312, year: 2015

  9. The effect of carbon dioxide at high pressure under different ...

    African Journals Online (AJOL)

    user

    2011-03-14

    Mar 14, 2011 ... the pulse beetle, Callosobruchus maculates. J. Insect Sci. 9: 58-61. George NM, Sonny BR (1998). Comparative effect of short term exposures of Callosobruchus subinnotatus to carbon dioxide, nitrogen, or low temperature on behaviour and fecundity. Entomologia Experimentalis et Applicata Vol. 89, No.

  10. 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

  11. Polyazidopyrimidines: High Energy Compounds and Precursors to Carbon Nanotubes (Postprint)

    National Research Council Canada - National Science Library

    Ye, Chengfeng; Gao, Haixiang; Boatz, Jerry A; Drake, Gregory W; Twamley, Brendan; Shreeve, Jean'ne M

    2006-01-01

    ...). The compound 4,4',6,6'-tetra(azido)azo-1,3,5-triazine (2), has a heat of formation of 2171 (6164 kJ kg -1) (Fig. 1). Recently it was demonstrated that 1 and 2 were good precursors to nano carbon nitride materials...

  12. Engineering of High-Toughness Carbon Nanotubes Hierarchically Laminated Composites

    Science.gov (United States)

    2012-01-27

    Bernsmann, F.; Ersen, O.; Voegel, J.-C.; Jan, E.; Kotov, N. A.; Ball, V. Melanin -Containing Films: Growth from Dopamine Solutions versus Layer-by-Layer...Chen, Wei; Doty, Chris; Xu, Chuanlai; Kotov, Nicholas A.. Smart Electronic Yarns and Wearable Fabrics for Human Biomonitoring made by Carbon Nanotube

  13. High resolution heart rate variability analysis in patients with angina pectoris during coronary artery bypass graft surgery

    Science.gov (United States)

    Mironov, V. A.; Mironova, T. F.; Kuvatov, V. A.; Nokhrina, O. Yu.; Kuvatova, E. V.

    2017-12-01

    The purpose of the study is approbation of the capabilities of high-resolution rhythmocardiography (RCG) for the determination of the actual cardiovascular status of operated patients with angina pectoris during coronary artery bypass graft surgery (CABGS) for myocardial revascularization. The research was done by means of a KAP-RK-02-Mikor hardware-software complex with a monitor record and the time- and frequency-domain analyses of heart rate variability (HRV). Monitor records were made at each stage of CABGS in 123 patients. As a result, HRV manifested itself as a fairly adequate and promising method for the determination of the cardiovascular status during CABGS. In addition, the data of the HRV study during CABGS testify to the capability of RCG to determine the high risk of life-threatening cardioarrhythmias before and during operation, to different changes in sinoatrial heart node (SN) dysregulation, and contain the HRV symptoms of a high death risk before, during and after shunting. The loss of the peripheral autonomic sympathetic and parasympathetic control in SN in the form of the autonomic cardioneuropathy syndrome is a predictor of the complications related to CABGS. The obtained data on RCG monitoring of HRV recording are suggestive of wide prospects of the high-resolution RCG method to be used in cardiac surgery as a whole. The actual multivariant dysregulations of SN pacemaker activity testify to its adequacy to the pathophysiology of each period of the cardiac operation, according to the initial ischemic damages and localization of cardiosurgical manipulations during CABGS.

  14. Patterned growth of carbon nanotubes obtained by high density plasma chemical vapor deposition

    Science.gov (United States)

    Mousinho, A. P.; Mansano, R. D.

    2015-03-01

    Patterned growth of carbon nanotubes by chemical vapor deposition represents an assembly approach to place and orient nanotubes at a stage as early as when they are synthesized. In this work, the carbon nanotubes were obtained at room temperature by High Density Plasmas Chemical Vapor Deposition (HDPCVD) system. This CVD system uses a new concept of plasma generation, where a planar coil coupled to an RF system for plasma generation was used with an electrostatic shield for plasma densification. In this mode, high density plasmas are obtained. We also report the patterned growth of carbon nanotubes on full 4-in Si wafers, using pure methane plasmas and iron as precursor material (seed). Photolithography processes were used to pattern the regions on the silicon wafers. The carbon nanotubes were characterized by micro-Raman spectroscopy, the spectra showed very single-walled carbon nanotubes axial vibration modes around 1590 cm-1 and radial breathing modes (RBM) around 120-400 cm-1, confirming that high quality of the carbon nanotubes obtained in this work. The carbon nanotubes were analyzed by atomic force microscopy and scanning electron microscopy too. The results showed that is possible obtain high-aligned carbon nanotubes with patterned growth on a silicon wafer with high reproducibility and control.

  15. Circulation, metabolism, and ventilation during prolonged exposure to carbon monoxide and to high altitude

    Energy Technology Data Exchange (ETDEWEB)

    Klausen, K.; Rasmussen, B; Gjellerod, H.; Madsen, H.; Petersen, E.

    1968-01-01

    Eight volunteers were exposed to CO (13% COHb) or high altitude (3454 m). There was no change in circulation, metabolism, or ventilation during CO exposure. With similar arterial O/sub 2/ concentration from high-altitude, V/sub e/ (BTPS) increased, Pa/sub CO/sub 2// decreased. Regulating mechanisms respond to a decrease in Pa/sub CO/sub 2// rather than a gereral lack in tissue O/sub 2/ per se.

  16. 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.

  17. Performance capabilities of EDM of high carbon high chromium steel with copper and brass electrodes

    Science.gov (United States)

    Surekha, B.; Swain, Sudiptha; Suleman, Abu Jafar; Choudhury, Suvan Dev

    2017-07-01

    The paper address the statistical modeling of input-output relationships of electric discharge machining. In the present work, peak current (I) pulse on time (T) and gap voltage of electric discharge machining (EDM) process are chosen as control parameters to analyze the performance of the process. The output characteristics, namely radial overcut, electrode wear rate (EWR) and metal removal rate (MRR) are treated as the responses. A full factorial design (FFD) of experiments has been used to conduct the experiments and linear regression models are developed for different process characteristics. While conducting the experiments, high carbon and high chromium steel is considered as work piece material and brass and copper are used as electrode material. It is important to note that the experimental conditions are kept similar while machining with the help of different electrode materials. The data obtained from the experiments has been used to develop the regression models for three process parameters for two electrode materials.

  18. Fe-Catalyzed Synthesis of Porous Carbons Spheres with High Graphitization Degree for High-Performance Supercapacitors

    Science.gov (United States)

    Zhu, Jun; Shi, Hongwei; Zhuo, Xin; Hu, Yalin

    2017-10-01

    We have developed a facile and efficient Fe-catalyzed method for fabrication of porous carbons spheres with high graphitization degree (GNPCs) using glucose as carbon precursor at relatively low carbonization temperature. GNPCs not only have relatively large accessible ion surface area to accommodate greater capacity but also high graphitization degree to accelerate ion diffusion. As a typical application, we demonstrate that GNPCs exhibit excellent electrochemical performance for use in supercapacitors, with high specific capacity of 150.6 F g-1 at current density of 1 A g-1 and good rate capability and superior cycling stability over 10,000 cycles, confirming their potential application for energy storage. Moreover, it is believed that this method offers a new strategy for synthesis of porous carbons with high graphitization degree.

  19. Climate policy and the optimal extraction of high- and low-carbon fossil fuels

    International Nuclear Information System (INIS)

    Smulders, S.; Van der Werf, E.

    2005-01-01

    We study how restricting CO2 emissions affects resource prices and depletion over time. We use a Hotelling-style model with two non- renewable fossil fuels that differ in their carbon content (e.g. coal and natural gas) and that are imperfect substitutes in final good production. We study both an unexpected constraint and an anticipated constraint. Both shocks induce intertemporal substitution of resource use. When emissions are unexpectedly restricted, it is cost-effective to use high-carbon resources relatively more (less) intensively on impact if this resource is relatively scarce (abundant). If the emission constraint is anticipated, it is cost-effective to use relatively more (less) of the low-carbon input before the constraint becomes binding, in order to conserve relatively more (less) of the high-carbon input for the period when climate policy is active in case the high-carbon resource is relatively scarce (abundant)

  20. Martensitic transformations, structure, and strengthness of processed high-nitrogen and high-carbon ferrous alloys

    Science.gov (United States)

    Kaputkina, L. M.; Prokoshkina, V. G.

    2003-10-01

    Structures and properties of metastable austenitic alloys Fe-18Cr-16Ni-I2Mn-(0.17 to 0. 50)N, Fe-18Cr-12Mn-(0.48 to 1.12)N, Fe-18Cr-(0.1 to 1.18)N, and Fe-(12 to 20)Ni-(0.6 to 1.3)C, Fe-(6 to 8)Mn-(0.6 to 1.0)C, Fe-(5 to 6)Cr-(4 to 5)Mn-(0.6 to 0.8)C, Fe-6Cr-(1.0 to 1.3)C resulting from martensitic transformations under cooling and cold deformation (CD), as well as following tempering processes, were studied by magnetometry, X-ray and electron microscopy analyses, hardness measurements and mechanical properties tests. Martensite with a b.c.t. lattice was formed in all alloys with M_s{>}-196^circC during cooling. Under CD transformations of γ{to}α, γ{to}\\varepsilon{to}α, or γ{to}\\varepsilon types were realized depending on the alloy composition. Carbon increased but nitrogen decreased stacking fault energy. Thus carbon assists α-martensite formation but nitrogen promotese. As CD level and/or concentration of carbon and nitrogen increase residual stresses resulting from the CD also increase. The martensitic transformation during CD can decrease the residual stresses. Kinetic of tempering of b.c.t. thermal martensite differs from those of CD-induced martensite. In the second case, deformation aging, texture, and residual stresses are more visible. The maximal strengthening under CD takes place in (Mn+N)-steels. (Cr+N) and (Cr+Mn+N)-steels are high-strength, non-magnetic and corrosion resistant and are easily hardened by a low level of plastic deformation.

  1. 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

  2. Aligned Carbon Nanotubes for Highly Efficient Energy Generation and Storage Devices

    Science.gov (United States)

    2012-01-24

    solution processing methods, including filtration, solution-casting, electrophoretic deposition, and Langmuir - Blodgett deposition. However, most...supercapacitors with environmentally friendly ionic liquid electrolytes. These new nanocomposite electrodes consist of the high-surface-area activated...carbons, carbon nanotubes, and ionic liquids as the integrated constituent components. The resultant composites show significantly improved charge

  3. 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

  4. High performance bulk metallic glass/carbon nanotube composite cathodes for electron field emission

    International Nuclear Information System (INIS)

    Hojati-Talemi, Pejman; Gibson, Mark A.; East, Daniel; Simon, George P.

    2011-01-01

    We report the preparation of new nanocomposites based on a combination of bulk metallic glass and carbon nanotubes for electron field emission applications. The use of bulk metallic glass as the matrix ensures high electrical and thermal conductivity, high thermal stability, and ease of processing, whilst the well dispersed carbon nanotubes act as highly efficient electron emitters. These advantages, alongside excellent electron emission properties, make these composites one of the best reported options for electron emission applications to date.

  5. High performance bulk metallic glass/carbon nanotube composite cathodes for electron field emission

    Energy Technology Data Exchange (ETDEWEB)

    Hojati-Talemi, Pejman [Department of Materials Engineering, Monash University, Clayton, Vic 3800 (Australia); Mawson Institute, University of South Australia, Mawson Lakes, SA 5095 (Australia); Gibson, Mark A. [Process Science and Engineering, Commonwealth Scientific and Industrial Research Organisation, Clayton, Vic 3168 (Australia); East, Daniel; Simon, George P. [Department of Materials Engineering, Monash University, Clayton, Vic 3800 (Australia)

    2011-11-07

    We report the preparation of new nanocomposites based on a combination of bulk metallic glass and carbon nanotubes for electron field emission applications. The use of bulk metallic glass as the matrix ensures high electrical and thermal conductivity, high thermal stability, and ease of processing, whilst the well dispersed carbon nanotubes act as highly efficient electron emitters. These advantages, alongside excellent electron emission properties, make these composites one of the best reported options for electron emission applications to date.

  6. Valuing carbon assets for high-tech with application to the wind energy industry

    International Nuclear Information System (INIS)

    Han, Liyan; Liu, Yang; Lin, Qiang; Huang, Gubo

    2015-01-01

    In contrast to the traditional methods for high-tech evaluation, we introduce a new, more active idea for considering the carbon asset effect, in addition to the economic and technological considerations for strategic significance. The method proposed in this paper considers a reduced amount of carbon emissions, less than that of the current industry baseline, to be an asset that is beneficial to a firm that adopts a new technology. The measured carbon asset values vary across different technologies, in different industries and over time. The new method is applied to the valuing of wind energy technology and uses the Weibull distribution to estimate the wind energy capacity and a concrete sensitivity analysis. These applications support the validity of the new method and show that the impact of the fluctuations of carbon sinks on the values of carbon assets is significantly greater than that of volatility in the production output. The paper also presents some policy recommendations based on the results. - Highlights: • Carbon asset dimension for high-tech evaluation. • Valuing wind energy technology by Weibull distribution. • Greater impact of the carbon sink price on the carbon asset value than that of production output. • The environmental risk could be measured based on the carbon asset assessment.

  7. Interactions of carbon monoxide and hemoglobin at high altitude

    Energy Technology Data Exchange (ETDEWEB)

    Collier, C.R. (Univ. of Southern California Medical Center, Los Angeles); Goldsmith, J.R.

    1983-01-01

    The health risks to U.S. populations who are exposed to ambient carbon monoxide and live at altitudes (such as Denver, Salt Lake City, and Albuquerque) were evaluated using a set of mathematical models. The assumption that a given increase in carboxyhemoglobin would require a more stringent volumetric air quality standard was tested. The results using the model predict that the 8-h or 1-h standards adopted for sea level condition need not be altered to protect individuals against health risks at altitude, if the standards are in volumetric terms. They would need to be reduced if the standards are left in gravimetric terms. If the guideline is to be based on a given decrement of oxygen tension, many other variables must be specified, but expected differences in ambient carbon monoxide have a small impact compared to the effect of altitude itself.

  8. Multilayer oxidation resistant coating for SiC coated carbon/carbon composites at high temperature

    International Nuclear Information System (INIS)

    Li Hejun; Jiao Gengsheng; Li Kezhi; Wang Chuang

    2008-01-01

    To prevent carbon/carbon (C/C) composites from oxidation, a multilayer coating based on molybdenum disilicide and titanium disilicide was formed using a two-step pack cementation technique in argon atmosphere. XRD and SEM analysis showed that the internal coating was a bond SiC layer that acts as a buffer layer, and that the external multilayer coating formed in the two-step pack cementation was composed of two MoSi 2 -TiSi 2 -SiC layers. This coating, which is characterized by excellent thermal shock resistance, could effectively protect the composites from exposure to an oxidizing atmosphere at 1773 K for 79 h. The oxidation of the coated C/C composites was primarily due to the reaction of C/C matrix and oxygen diffusing through the penetrable cracks in the coating

  9. Ultra High Energy Density Cathodes with Carbon Nanotubes

    Science.gov (United States)

    2013-12-10

    a) Carbon nanotube paper coated with NCA cathode composite for testing as positive electrode in Li-ion battery (b) Comparison of NCA specific...received and purified CNT electrodes coated with NCA cathode composite. (b) Discharge capacities as a function of rate and cycle for NCA on Al and...thickness increases. The first approach was to cast SOA NCA cathode composites onto CNT current collectors using an adjustable blade coater. The

  10. 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

  11. Preoperative mapping of arterial spinal supply using 3.0-T MR angiography with an intravasal contrast medium and high-spatial-resolution steady-state

    International Nuclear Information System (INIS)

    Mordasini, Pasquale; El-Koussy, Marwan; Schmidli, Jürg; Bonel, Harald Marcel; Ith, Michael; Gralla, Jan; Schroth, Gerhard; Hoppe, Hanno

    2012-01-01

    Introduction: Preoperative mapping of the arterial spinal supply prior to thoracoabdominal aortic aneurysm repair is highly relevant because of high risk for postoperative ischemic spinal cord injuries such as paraparesis or paraplegia. Methods: Twenty-four consecutive patients prior to surgical thoracoabdominal aortic aneurysm repair were investigated. All patients underwent steady-state MR angiography (MRA) of the spinal vasculature with 3-T MRI. The sequence used was a steady-state coronary 3D FLASH with 0.7-mm isotropic voxels. MRA was performed using an intravasal contrast agent. Studies were evaluated by three readers including delineation of arterial spinal supply including both aortic origin and spinal canal entry by three readers. Results: Identification and localization of the Adamkiewicz artery and its spinal canal entry was successful in all patients. Overall depiction of the vascular anatomy was graded as very good in 3 (12.5%), good in 14 (58.4%), sufficient in 5 (20.8%), and poor in 2 (8.3%) patients. Depiction of segmental artery aortic exit level was graded as good in 6 (25.0%), sufficient in 10 (41.7%), poor in 4 (16.7%) and not identifiable in 4 (16.7%) patients. Delineation of segmental artery entry level into the spinal canal was graded as very good in 4 (16.7%), good in 11 (45.8%), sufficient in 6 (25.0%), and poor in 3 (12.5%) patients. Conclusions: The use of 3-T MRA with an intravascular contrast agent and steady-state enables AKA localization including its segmental arteries with regard to the level of aortic origin and spinal canal entry in most patients.

  12. Experiment Plan of High Temperature Steam and Carbon dioxide Co-electrolysis for Synthetic Gas Production

    International Nuclear Information System (INIS)

    Yoon, Duk-Joo; Ko, Jae-Hwa

    2008-01-01

    Currently, Solid oxide fuel cells (SOFC) come into the spotlight in the middle of the energy technologies of the future for highly effective conversion of fossil fuels into electricity without carbon dioxide emission. The SOFC is a reversible cell. By applying electrical power to the cell, which is solid oxide electrolysis cell (SOEC), it is possible to produce synthetic gas (syngas) from high temperature steam and carbon dioxide. The produced syngas (hydrogen and carbon monoxide) can be used for synthetic fuels. This SOEC technology can use high temperature from VHTRs for high efficiency. This paper describes KEPRI's experiment plan of high temperature steam and carbon co-electrolysis for syngas production using SOEC technology

  13. Late gestational hypoxia and a postnatal high salt diet programs endothelial dysfunction and arterial stiffness in adult mouse offspring.

    Science.gov (United States)

    Walton, Sarah L; Singh, Reetu R; Tan, Tiffany; Paravicini, Tamara M; Moritz, Karen M

    2016-03-01

    Gestational hypoxia and high dietary salt intake have both been associated with impaired vascular function in adulthood. Using a mouse model of prenatal hypoxia, we examined whether a chronic high salt diet had an additive effect in promoting vascular dysfunction in offspring. Pregnant CD1 dams were placed in a hypoxic chamber (12% O2) or housed under normal conditions (21% O2) from embryonic day 14.5 until birth. Gestational hypoxia resulted in a reduced body weight for both male and female offspring at birth. This restriction in body weight persisted until weaning, after which the animals underwent catch-up growth. At 10 weeks of age, a subset of offspring was placed on a high salt diet (5% NaCl). Pressurized myography of mesenteric resistance arteries at 12 months of age showed that both male and female offspring exposed to maternal hypoxia had significantly impaired endothelial function, as demonstrated by impaired vasodilatation to ACh but not sodium nitroprusside. Endothelial dysfunction caused by prenatal hypoxia was not exacerbated by postnatal consumption of a high salt diet. Prenatal hypoxia increased microvascular stiffness in male offspring. The combination of prenatal hypoxia and a postnatal high salt diet caused a leftward shift in the stress-strain relationship in both sexes. Histopathological analysis of aortic sections revealed a loss of elastin integrity and increased collagen, consistent with increased vascular stiffness. These results demonstrate that prenatal hypoxia programs endothelial dysfunction in both sexes. A chronic high salt diet in postnatal life had an additive deleterious effect on vascular mechanics and structural characteristics in both sexes. © 2015 The Authors. The Journal of Physiology © 2015 The Physiological Society.

  14. 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.

  15. 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 (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.

  16. Vascular reactivity of mesenteric arteries and veins to endothelin-1 in a murine model of high blood pressure.

    Science.gov (United States)

    Pérez-Rivera, Alex A; Fink, Gregory D; Galligan, James J

    2005-06-01

    We characterized vascular reactivity to endothelin-1 (ET-1) in mesenteric vessels from DOCA-salt hypertensive and SHAM control mice and assessed the effect that endothelial-derived vasodilators have on ET-1-induced vasoconstriction. Changes in the diameter of unpressurized small mesenteric arteries and veins (100- to 300-microm outside diameter) were measured in vitro using computer-assisted video microscopy. Veins were more sensitive than arteries to the contractile effects of ET-1. There was a decrease in arterial maximal responses (E(max)) compared to veins, this effect was larger in DOCA-salt arteries. The selective ET(B) receptor agonist, sarafotoxin 6c (S6c), contracted DOCA-salt and SHAM veins but did not contract arteries. The ET(B) receptor antagonist, BQ-788 (100 nM), but not the ET(A) receptor antagonist, BQ-610 (100 nM), blocked S6c responses. BQ-610 partially inhibited responses to ET-1 in mesenteric veins from DOCA-salt and SHAM mice while BQ-788 did not affect responses to ET-1. Co-administration of both antagonists inhibited responses to ET-1 to a greater extent than BQ-610 alone suggesting a possible functional interaction between ET(A) and ET(B) receptors. Responses to ET-1 in mesenteric arteries were completely inhibited by BQ-610 while BQ-788 did not affect arterial responses. Nitric oxide synthase inhibition potentiated ET-1 responses in veins from SHAM but not DOCA-salt mice. There was a prominent role for ET-mediated nitric oxide release in DOCA-salt but not SHAM arteries. In summary, these studies showed a differential regulation of ET-1 contractile mechanisms between murine mesenteric arteries and veins.

  17. Rice bran protein hydrolysates reduce arterial stiffening, vascular remodeling and oxidative stress in rats fed a high-carbohydrate and high-fat diet.

    Science.gov (United States)

    Senaphan, Ketmanee; Sangartit, Weerapon; Pakdeechote, Poungrat; Kukongviriyapan, Veerapol; Pannangpetch, Patchareewan; Thawornchinsombut, Supawan; Greenwald, Stephen E; Kukongviriyapan, Upa

    2018-02-01

    Rice bran protein hydrolysates (RBPH) contain highly nutritional proteins and antioxidant compounds which show benefits against metabolic syndrome (MetS). Increased arterial stiffness and the components of MetS have been shown to be associated with an increased risk of cardiovascular disease. This study aimed to investigate whether RBPH could alleviate the metabolic disorders, arterial stiffening, vascular remodeling, and oxidative stress in rats fed a high-carbohydrate and high-fat (HCHF) diet. Male Sprague-Dawley rats were fed either a standard chow and tap water or a HCHF diet and 15 % fructose solution for 16 weeks. HCHF rats were treated orally with RBPH (250 or 500 mg/kg/day) for the final 6 weeks of the experimental period. Rats fed with HCHF diet had hyperglycemia, insulin resistance, dyslipidemia, hypertension, increased aortic pulse wave velocity, aortic wall hypertrophy and vascular remodeling with increased MMP-2 and MMP-9 expression. RBPH supplementation significantly alleviated these alterations (P stress was also alleviated after RBPH treatment by decreasing plasma malondialdehyde, reducing superoxide production and suppressing p47 phox NADPH oxidase expression in the vascular tissues of HCHF rats. RBPH increased plasma nitrate/nitrite level and up-regulated eNOS expression in the aortas of HCHF-diet-fed rats, indicating that RBPH increased NO production. RBPH mitigate the deleterious effects of HCHF through potential mechanisms involving enhanced NO bioavailability, anti-ACE, anti-inflammatory and antioxidant properties. RBPH could be used as dietary supplements to minimize oxidative stress and vascular alterations triggered by MetS.

  18. 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.

  19. Changes in endothelial function, arterial stiffness and blood pressure in pregnant women after consumption of high-flavanol and high-theobromine chocolate: a double blind randomized clinical trial.

    Science.gov (United States)

    Babar, Asma; Bujold, Emmanuel; Leblanc, Vicky; Lavoie-Lebel, Élise; Paquette, Joalee; Bazinet, Laurent; Lemieux, Simone; Marc, Isabelle; Abdous, Belkacem; Dodin, Sylvie

    2018-04-16

    The aim of this 2-group, parallel, double blind single-centre RCT was to evaluate the acute and chronic impacts of high flavanol high theobromine (HFHT) chocolate consumption on endothelial function, arterial stiffness and blood pressure (BP) in women at risk of preeclampsia. 131 pregnant women considered at risk of preeclampsia based on uterine artery Doppler ultrasound were divided into two groups (HFHT or low flavanol and theobromine chocolate (LFLT). Acute changes in plasma flavanol and theobromine, peripheral arterial tonometry and BP were evaluated at randomization (0, 60 and 120 min after a single 40-g dose of chocolate) and again 6 and 12 weeks after daily 30-g chocolate intake. The EndoPAT 2000 provided reactive hyperemia index (RHI) and adjusted augmentation index (AIx) as markers for endothelial function and arterial stiffness, respectively. Compared with LFLT, acute HFHT intake significantly increased plasma epicatechin and theobromine (p theobromine (p theobromine concentrations and decreased arterial stiffness, with no effect on endothelial function and a marginal increase in diastolic BP. Chronic HFHT intake increased plasma theobromine, though it did not have positive impacts on endothelial function, arterial stiffness or BP when compared to LFLT in pregnant women at risk of PE.

  20. A doped activated carbon prepared from polyaniline for high performance supercapacitors

    Energy Technology Data Exchange (ETDEWEB)

    Li, Limin; Liu, Enhui; Li, Jian; Yang, Yanjing; Shen, Haijie; Huang, Zhengzheng; Xiang, Xiaoxia; Li, Wen [Key Laboratory of Environmentally Friendly Chemistry and Applications of Ministry of Education, College of Chemistry, Xiangtan University, Hunan 411105 (China)

    2010-03-01

    A novel doped activated carbon has been prepared from H{sub 2}SO{sub 4}-doped polyaniline which is prepared by the oxypolymerization of aniline. The morphology, surface chemical composition and surface area of the carbon have been investigated by scanning electron microscope, X-ray photoelectron spectroscopy and Brunaner-Emmett-Teller measurement, respectively. Electrochemical properties of the doped activated carbon have been studied by cyclic voltammograms, galvanostatic charge/discharge, and electrochemical impedance spectroscopy measurements in 6 mol l{sup -1} KOH. The specific capacitance of the carbon is as high as 235 F g{sup -1}, the specific capacitance hardly decreases at a high current density 11 A g{sup -1} after 10,000 cycles, which indicates that the carbon possesses excellent cycle durability and may be a promising candidate for supercapacitors. (author)

  1. Myocardial perfusion assessment by dual-energy computed tomography in patients with intermediate to high likelihood of coronary artery disease

    International Nuclear Information System (INIS)

    De Zam, M.C.; Capunay, C.; Rodriguez Granillo, G.A.; Deviggiano, A.; Campisi, R.; Munain, M. López de; Vallejos, J.; Carrascosa, P.M.

    2015-01-01

    Objectives. We sought to explore the feasibility and diagnostic performance of dual-energy computed tomography (DECT) for the evaluation of myocardial perfusion in patients with intermediate to high likelihood of coronary artery disease (CAD), and to assess the impact of beam hardening artifacts (HAE). Methods. The present prospective study involved patients with known or suspected CAD referred for myocardial perfusion imaging by single-photon emission computed tomography (SPECT). Twenty patients were included in the study protocol, and scanned using DECT imaging (n = 20). The same pharmacological stress was used for DECT and SPECT scans. Results. A total of 680 left ventricular segments were evaluated by DECT and SPECT. The contrast to noise ratio was 8.8±2.9. The diagnostic performance of DECT was very good in identifying perfusion defects [area under ROC curve (AUC) of DECT 0.90 (0.86-0.94)] compared with SPECT, and remained unaffected when including only segments affected by beam hardening artifacts (BHA) [AUC= DECT 0.90 (0.84-0.96)]. Conclusions. In this pilot investigation, myocardial perfusion assessment by DECT imaging in patients with intermediate to high likelihood of CAD was feasible and remained unaffected by the presence of BHA. (authors) [es

  2. 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.

  3. CDSD-4000: High-resolution, high-temperature carbon dioxide spectroscopic databank

    International Nuclear Information System (INIS)

    Tashkun, S.A.; Perevalov, V.I.

    2011-01-01

    We present a high-resolution, high-temperature version of the Carbon Dioxide Spectroscopic Databank called CDSD-4000. The databank contains the line parameters (positions, intensities, air- and self-broadened half-widths, coefficients of temperature dependence of air- and self-broadened half-widths, and air-broadened pressure shifts) of the four most abundant isotopologues of CO 2 . A reference temperature is 296 K and an intensity cutoff is 10 -27 cm -1 /molecule cm -2 at 4000 K. The databank has 628,324,454 entries, covers the 226-8310 cm -1 spectral range and designed for the temperature range 2500-5000 K. Format of CDSD-4000 is similar to that of HITRAN-2008. The databank has been generated within the framework of the method of effective operators and based on the global fittings of spectroscopic parameters (parameters of the effective Hamiltonians and effective dipole moment operators) to observed data collected from the literature. The databank is useful for studying high-temperature radiative properties of CO 2 , including exoplanets atmospheres, aerothemal modeling for Mars entry missions, high-temperature laboratory spectra, and industrial applications. CDSD-4000 is freely accessible via the Internet site (ftp://ftp.iao.ru/pub/CDSD-4000).

  4. Effect of small addition of Cr on stability of retained austenite in high carbon steel

    Energy Technology Data Exchange (ETDEWEB)

    Hossain, Rumana; Pahlevani, Farshid, E-mail: f.pahlevani@unsw.edu.au; Sahajwalla, Veena

    2017-03-15

    High carbon steels with dual phase structures of martensite and austenite have considerable potential for industrial application in high abrasion environments due to their hardness, strength and relatively low cost. To design cost effective high carbon steels with superior properties, it is crucial to identify the effect of Chromium (Cr) on the stability of retained austenite (RA) and to fully understand its effect on solid-state phase transition. This study addresses this important knowledge gap. Using standard compression tests on bulk material, quantitative X-ray diffraction analysis, nano-indentation on individual austenitic grains, transmission electron microscopy and electron backscatter diffraction–based orientation microscopy techniques, the authors investigated the effect of Cr on the microstructure, transformation behaviour and mechanical stability of retained austenite in high carbon steel, with varying Cr contents. The results revealed that increasing the Cr %, altered the morphology of the RA and increased its stability, consequently, increasing the critical pressure for martensitic transformation. This study has critically addressed the elastoplastic behaviour of retained austenite – and provides a deep understanding of the effect of small additions of Cr on the metastable austenite of high carbon steel from the macro- to nano-level. Consequently, it paves the way for new applications for high carbon low alloy steels. - Highlights: • Effect of small addition of Cr on metastable austenite of high carbon steel from the macro- to nano-level • A multi-scale study of elastoplastic behaviour of retained austenite in high carbon steel • The mechanical stability of retained austenite during plastic deformation increased with increasing Cr content • Effect of grain boundary misorientation angle on hardness of individual retained austenite grains in high carbon steel.

  5. Freestanding bucky paper with high strength from multi-wall carbon nanotubes

    International Nuclear Information System (INIS)

    Li, Zhonglai; Xu, Ju; O'Byrne, Justin P.; Chen, Lan; Wang, Kaixue; Morris, Michael A.; Holmes, Justin D.

    2012-01-01

    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 −1 was obtained by Supercritical Fluid (SCF) drying technique. -- Highlights: ► Multi-wall carbon nanotube bucky paper. ► Structural defects of carbon nanotubes. ► CoMo catalyst. ► Tensile strength of bucky paper.

  6. High-resolution forest carbon stocks and emissions in the Amazon.

    Science.gov (United States)

    Asner, Gregory P; Powell, George V N; Mascaro, Joseph; Knapp, David E; Clark, John K; Jacobson, James; Kennedy-Bowdoin, Ty; Balaji, Aravindh; Paez-Acosta, Guayana; Victoria, Eloy; Secada, Laura; Valqui, Michael; Hughes, R Flint

    2010-09-21

    Efforts to mitigate climate change through the Reduced Emissions from Deforestation and Degradation (REDD) depend on mapping and monitoring of tropical forest carbon stocks and emissions over large geographic areas. With a new integrated use of satellite imaging, airborne light detection and ranging, and field plots, we mapped aboveground carbon stocks and emissions at 0.1-ha resolution over 4.3 million ha of the Peruvian Amazon, an area twice that of all forests in Costa Rica, to reveal the determinants of forest carbon density and to demonstrate the feasibility of mapping carbon emissions for REDD. We discovered previously unknown variation in carbon storage at multiple scales based on geologic substrate and forest type. From 1999 to 2009, emissions from land use totaled 1.1% of the standing carbon throughout the region. Forest degradation, such as from selective logging, increased regional carbon emissions by 47% over deforestation alone, and secondary regrowth provided an 18% offset against total gross emissions. Very high-resolution monitoring reduces uncertainty in carbon emissions for REDD programs while uncovering fundamental environmental controls on forest carbon storage and their interactions with land-use change.

  7. X-ray photoelectron spectroscopy characterization of high dose carbon-implanted steel and titanium alloys

    Science.gov (United States)

    Viviente, J. L.; García, A.; Alonso, F.; Braceras, I.; Oñate, J. I.

    1999-04-01

    A study has been made of the depth dependence of the atomic fraction and chemical bonding states of AISI 440C martensitic stainless steel and Ti-6Al-4V alloy implanted with 75 keV C + at very high doses (above 10 18 ions cm -2), by means of X-ray photoelectron spectroscopy combined with an Ar + sputtering. A Gaussian-like carbon distribution was observed on both materials at the lowest implanted dose. More trapezoidal carbon depth-profiles were found with increasing implanted doses, and a pure carbon layer was observed only on the titanium alloy implanted at the highest dose. The implanted carbon was combined with both base metal and carbon itself to form metallic carbides and graphitic carbon. Furthermore, carbon-enriched carbides were also found by curve fitting the C 1s spectra. The titanium alloy showed a higher carbidic contribution than the steel implanted at the same C + doses. A critical carbon concentrations of about 33 at.% and 23 at.% were measured for the formation of C-C bonds in Ti-6Al-4V and steel samples, respectively. The carbon atoms were bound with metal to form carbidic compounds until these critical concentrations were reached; when this C concentration was exceeded the proportion of C-C bonds increased and resulted in the growth of carbonaceous layers.

  8. High-cycle electromechanical aging of dielectric elastomer actuators with carbon-based electrodes

    Science.gov (United States)

    de Saint-Aubin, C. A.; Rosset, S.; Schlatter, S.; Shea, H.

    2018-07-01

    We present high-cycle aging tests of dielectric elastomer actuators (DEAs) based on silicone elastomers, reporting on the time-evolution of actuation strain and of electrode resistance over millions of cycles. We compare several types of carbon-based electrodes, and for the first time show how the choice of electrode has a dramatic influence on DEA aging. An expanding circle DEA configuration is used, consisting of a commercial silicone membrane with the following electrodes: commercial carbon grease applied manually, solvent-diluted carbon grease applied by stamping (pad printing), loose carbon black powder applied manually, carbon black powder suspension applied by inkjet-printing, and conductive silicone-carbon composite applied by stamping. The silicone-based DEAs with manually applied carbon grease electrodes show the shortest lifetime of less than 105 cycles at 5% strain, while the inkjet-printed carbon powder and the stamped silicone-carbon composite make for the most reliable devices, with lifetimes greater than 107 cycles at 5% strain. These results are valid for the specific dielectric and electrode configurations that were tested: using other dielectrics or electrode formulations would lead to different lifetimes and failure modes. We find that aging (as seen in the change in resistance and in actuation strain versus cycle number) is independent of the actuation frequency from 10 Hz to 200 Hz, and depends on the total accumulated time the DEA spends in an actuated state.

  9. Carbon dioxide and water vapor high temperature electrolysis

    Science.gov (United States)

    Isenberg, Arnold O.; Verostko, Charles E.

    1989-01-01

    The design, fabrication, breadboard testing, and the data base obtained for solid oxide electrolysis systems that have applications for planetary manned missions and habitats are reviewed. The breadboard tested contains sixteen tubular cells in a closely packed bundle for the electrolysis of carbon dioxide and water vapor. The discussion covers energy requirements, volume, weight, and operational characteristics related to the measurement of the reactant and product gas compositions, temperature distribution along the electrolyzer tubular cells and through the bundle, and thermal energy losses. The reliability of individual cell performance in the bundle configuration is assessed.

  10. Atlas of high resolution infrared spectra of carbon dioxide

    Science.gov (United States)

    Rinsland, C. P.; Benner, D. C.; Devi, V. M.; Ferry, P. S.; Sutton, C. H.; Richardson, D. J.

    1984-01-01

    A long path, low pressure laboratory spectrum of carbon dioxide is presented for the spectral region 1830 to 2010/cm. The data were recorded at 0.01/cm resolution and room temperature with the Fourier transform spectrometer in the McMath solar telescope complex at Kitt Peak National Observatory. A list of positions and assignments is given for the 1038 lines observed in this region. A total of 30 bands and subbands of 12C1602, 13C1602, 12C160180, 12C160170, and 13C160180 were observed. Previously announced in STAR as N83-19598

  11. High-performance supercapacitors based on vertically aligned carbon nanotubes and nonaqueous electrolytes

    Science.gov (United States)

    Kim, Byungwoo; Chung, Haegeun; Kim, Woong

    2012-04-01

    We demonstrate the high performance of supercapacitors fabricated with vertically aligned carbon nanotubes and nonaqueous electrolytes such as ionic liquids and conventional organic electrolytes. Specific capacitance, maximum power and energy density of the supercapacitor measured in ionic liquid were ˜75 F g-1, ˜987 kW kg-1 and ˜27 W h kg-1, respectively. The high power performance was consistently indicated by a fast relaxation time constant of 0.2 s. In addition, electrochemical oxidation of the carbon nanotubes improved the specific capacitance (˜158 F g-1) and energy density (˜53 W h kg-1). Both high power and energy density could be attributed to the fast ion transport realized by the alignment of carbon nanotubes and the wide operational voltage defined by the ionic liquid. The demonstrated carbon-nanotube- and nonaqueous-electrolyte-based supercapacitors show great potential for the development of high-performance energy storage devices.

  12. High-performance supercapacitors based on vertically aligned carbon nanotubes and nonaqueous electrolytes.

    Science.gov (United States)

    Kim, Byungwoo; Chung, Haegeun; Kim, Woong

    2012-04-20

    We demonstrate the high performance of supercapacitors fabricated with vertically aligned carbon nanotubes and nonaqueous electrolytes such as ionic liquids and conventional organic electrolytes. Specific capacitance, maximum power and energy density of the supercapacitor measured in ionic liquid were ~75 F g(-1), ~987 kW kg(-1) and ~27 W h kg(-1), respectively. The high power performance was consistently indicated by a fast relaxation time constant of 0.2 s. In addition, electrochemical oxidation of the carbon nanotubes improved the specific capacitance (~158 F g(-1)) and energy density (~53 W h kg(-1)). Both high power and energy density could be attributed to the fast ion transport realized by the alignment of carbon nanotubes and the wide operational voltage defined by the ionic liquid. The demonstrated carbon-nanotube- and nonaqueous-electrolyte-based supercapacitors show great potential for the development of high-performance energy storage devices. © 2012 IOP Publishing Ltd

  13. 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.

  14. Hollow Carbon Nanofiber-Encapsulated Sulfur Cathodes for High Specific Capacity Rechargeable Lithium Batteries

    KAUST Repository

    Zheng, Guangyuan; Yang, Yuan; Cha, Judy J.; Hong, Seung Sae; Cui, Yi

    2011-01-01

    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

  15. Highly stable carbon coated Mg2Si intermetallic nanoparticles for lithium-ion battery anode

    Science.gov (United States)

    Tamirat, Andebet Gedamu; Hou, Mengyan; Liu, Yao; Bin, Duan; Sun, Yunhe; Fan, Long; Wang, Yonggang; Xia, Yongyao

    2018-04-01

    Silicon is an ideal candidate anode material for Li-ion batteries (LIBs). However, it suffers from rapid capacity fading due to large volume expansion upon lithium insertion. Herein, we design and fabricate highly stable carbon coated porous Mg2Si intermetallic anode material using facile mechano-thermal technique followed by carbon coating using thermal vapour deposition (TVD), toluene as carbon source. The electrode exhibits an excellent first reversible capacity of 726 mAh g-1 at a rate of 100 mA g-1. More importantly, the electrode demonstrates high rate capability (380 mAh g-1 at high rate of 2 A g-1) as well as high cycle stability, with capacity retentions of 65% over 500 cycles. These improvements are attributable to both Mg supporting medium and the uniform carbon coating, which can effectively increase the conductivity and electronic contact of the active material and protects large volume alterations during the electrochemical cycling process.

  16. High-Performance Modeling of Carbon Dioxide Sequestration by Coupling Reservoir Simulation and Molecular Dynamics

    KAUST Repository

    Bao, Kai; Yan, Mi; Allen, Rebecca; Salama, Amgad; Lu, Ligang; Jordan, Kirk E.; Sun, Shuyu; Keyes, David E.

    2015-01-01

    The present work describes a parallel computational framework for carbon dioxide (CO2) sequestration simulation by coupling reservoir simulation and molecular dynamics (MD) on massively parallel high-performance-computing (HPC) systems

  17. Plasma Treatment of Carbon Nanotubes Applied to Improve the High Performance of Carbon Nanofiber Supercapacitors

    International Nuclear Information System (INIS)

    Chang, Wei-Min; Wang, Cheng-Chien; Chen, Chuh-Yung

    2015-01-01

    Graphical abstract: This article focused on improving conductivity of carbon nanofibers (CNFs) by added plasma-treatment carbon nanotubes (CNTs). The plasma modification method avoided the destruction of the length and structure of the CNTs and maintained their good electrical properties. Through this method, the relation between conductivity and surface activity site of CNFs was investigated. The results shown that he CNTs-MA added to the CNFs successfully maintained the activity sites on the surface of the CNFs and provide a good electric network to enhance the supercapacitor performance of the CNFs. - Highlights: • The plasma modification method avoided the destruction of the length and structure of the CNTs and maintained their good electrical properties. • The highest conductivity of the CNTs-MA/CNF was 5.2 s/cm at 2.5 wt.% of CNTs-MA addition. It was increased to 8.7 time. • The CNTs-MA added to the CNFs successfully maintained the activity sites on the surface of the CNFs and provide a good electric network to enhance the supercapacitor performance of the CNFs. The highest capacitance was 382 F/g. - Abstract: Plasma-treatment carbon nanotubes (CNTs) grafted with maleic anhydride (MA) were embedded in polyacryonitrile nanofibers via electrospinning and subsequently carbonizated at 800 °C to fabricate carbon nanofibers (CNFs). The grafted degree of MA on CNTs (CNTs-MA) was determined via Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. The morphology, surface composition and conductivity of the CNTs-MA/CNF were characterized using electron microscopy, X-ray photoelectron and electrochemical impedance spectroscopy, respectively. CNTs-MA not only affected the conductivity of the CNFs but also the types of the nitrogen functional groups that could be represented as active sites on the CNFs to enhance the performance of the supercapacitors. When 2.5 wt.% CNTs-MA was embedded in the CNFs, the highest conductivity was obtained at

  18. Accelerated Carbonation of Steel Slag Compacts: Development of High-Strength Construction Materials

    Energy Technology Data Exchange (ETDEWEB)

    Quaghebeur, Mieke; Nielsen, Peter, E-mail: peter.nielsen@vito.be; Horckmans, Liesbeth [Sustainable Materials Management, VITO, Mol (Belgium); Van Mechelen, Dirk [RECMIX bvba, Genk (Belgium)

    2015-12-17

    Mineral carbonation involves the capture and storage of carbon dioxide in carbonate minerals. Mineral carbonation presents opportunities for the recycling of steel slags and other alkaline residues that are currently landfilled. The Carbstone process was initially developed to transform non-hydraulic steel slags [stainless steel (SS) slag and basic oxygen furnace (BOF) slags] in high-quality construction materials. The process makes use of accelerated mineral carbonation by treating different types of steel slags with CO{sub 2} at elevated pressure (up to 2 MPa) and temperatures (20–140°C). For SS slags, raising the temperature from 20 to 140°C had a positive effect on the CO{sub 2} uptake, strength development, and the environmental properties (i.e., leaching of Cr and Mo) of the carbonated slag compacts. For BOF slags, raising the temperature was not beneficial for the carbonation process. Elevated CO{sub 2} pressure and CO{sub 2} concentration of the feed gas had a positive effect on the CO{sub 2} uptake and strength development for both types of steel slags. In addition, the compaction force had a positive effect on the strength development. The carbonates that are produced in situ during the carbonation reaction act as a binder, cementing the slag particles together. The carbonated compacts (Carbstones) have technical properties that are equivalent to conventional concrete products. An additional advantage is that the carbonated materials sequester 100–150 g CO{sub 2}/kg slag. The technology was developed on lab scale by the optimization of process parameters with regard to compressive strength development, CO{sub 2} uptake, and environmental properties of the carbonated construction materials. The Carbstone technology was validated using (semi-)industrial equipment and process conditions.

  19. 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

  20. 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.

  1. High incidence of the median artery of the forearm in a sample of recent southern African cadavers.

    Science.gov (United States)

    Henneberg, M; George, B J

    1992-01-01

    Observations of the presence of the median artery, providing substantial blood supply to the hand, were conducted on 96 dissected forearms of 15 adult African females and 49 adult males. The artery has a much higher incidence (27.1%) than previously reported by any author. There is no significant difference in its occurrence between sexes, nor between right and left limbs. The artery seems to occur more often bilaterally than unilaterally. The presence of the artery is not related to age. From a theoretical standpoint it is difficult to accept that a structure present in more than 1 in 4 of individuals should be considered an 'anomaly' or a 'variant'. A different approach to description of normal human anatomy is therefore necessary--that of presenting alternative anatomical patterns of equal standing rather than a single 'normal' pattern. Images Fig. 1 Fig. 2 Fig. 3 PMID:1452474

  2. A Study of the Effect of Interrupted Quenches on a Thermomechanically Processed High Carbon Steel.

    Science.gov (United States)

    1982-10-01

    steel . Successful martempering requires a cooling rate sufficient to avoid the nose of the C- curve and thus prevent significant bainite formation. When...STUDY OF THE EFFECT OF INTERRUPTED QUENCHES ON A THERMONECHANICALLY PROCESSED HIGH CARBON STEEL by Steven A. Barton October 1982 Thesis Advisor: T.R...unlimited. A Study of the Effect of Interrupted Quenches on a Thermomechanically Processed High Carbon Steel by Steven A. Barton Lieutenant, United

  3. Left ventricular mechanics in humans with high aerobic fitness: adaptation independent of structural remodelling, arterial haemodynamics and heart rate

    Science.gov (United States)

    Stöhr, Eric J; McDonnell, Barry; Thompson, Jane; Stone, Keeron; Bull, Tom; Houston, Rory; Cockcroft, John; Shave, Rob

    2012-01-01

    Individuals with high aerobic fitness have lower systolic left ventricular strain, rotation and twist (‘left ventricular (LV) mechanics’) at rest, suggesting a beneficial reduction in LV myofibre stress and more efficient systolic function. However, the mechanisms responsible for this functional adaptation are not known and the influence of aerobic fitness on LV mechanics during dynamic exercise has never been studied. We assessed LV mechanics, LV wall thickness and dimensions, central augmentation index (AIx), aortic pulse wave velocity (aPWV), blood pressure and heart rate in 28 males (age: 21 ± 2 years SD) with a consistent physical activity level (no change >6 months). Individuals were examined at rest and during exercise (40% peak exercise capacity) and separated post hoc into a moderate and high aerobic fitness group (: 49 ± 5 and 63 ± 7 ml kg−1 min−1, respectively, P 0.05). However, for the same AIx, the high group had significantly lower LV apical rotation (P = 0.002) and LV twist (P = 0.003) while basal rotation and strain indices did not differ between groups (P > 0.05). We conclude that young males with high aerobic fitness have lower LV apical rotation at rest and during submaximal exercise that can occur without changes in gross LV structure, arterial haemodynamics or heart rate. The findings suggest a previously unknown type of physiological adaptation of the left ventricle that may have important implications for exercise training in older individuals and patient populations in which exercise training has previously failed to show clear benefits for LV function. PMID:22431336

  4. Highly sensitive and selective determination of methylergometrine maleate using carbon nanofibers/silver nanoparticles composite modified carbon paste electrode

    International Nuclear Information System (INIS)

    Kalambate, Pramod K.; Rawool, Chaitali R.; Karna, Shashi P.; Srivastava, Ashwini K.

    2016-01-01

    A highly sensitive and selective voltammetric method for determination of Methylergometrine maleate (MM) in pharmaceutical formulations, urine and blood serum samples has been developed based on enhanced electrochemical response of MM at carbon nanofibers and silver nanoparticles modified carbon paste electrode (CNF-AgNP-CPE). The electrode material was characterized by various techniques viz., X-ray diffraction, scanning electron microscopy and energy dispersive X-ray spectroscopy. The electrocatalytic response of MM at CNF-AgNP-CPE was studied by cyclic voltammetry (CV), differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy (EIS). Under optimized conditions, the proposed sensor exhibits excellent electrochemical response towards MM. The DPV study shows greatly enhanced electrochemical signal for MM at CNF-AgNP-CPE lending high sensitivity to the proposed sensor for MM detection. The peak (I p ) current for MM is found to be rectilinear in the range 4.0 × 10 −8 –2.0 × 10 −5 M with a detection limit of 7.1 × 10 −9 M using DPV. The feasibility of the proposed sensor in analytical applications was investigated by conducting experiments on commercial pharmaceutical formulations, human urine and blood serum samples, which yielded satisfactory recoveries of MM. The proposed electrochemical sensor offers high sensitivity, selectivity, reproducibility and practical utility. We recommend it as an authentic and productive electrochemical sensor for successful determination of MM. - Highlights: • Voltammetric sensor for methylergometrine maleate using carbon nanofibers and silver nanoparticle - carbon paste electrode • Wide working range, good reproducibility, fast response and high stability were the main advantages of the proposed sensor • Analysis of methylergometrine maleate in pharmaceutical formulations, urine and blood serum samples • Lowest limit of detection obtained for methylergometrine maleate

  5. Physiological dead space and arterial carbon dioxide contributions to exercise ventilatory inefficiency in patients with reduced or preserved ejection fraction heart failure.

    Science.gov (United States)

    Van Iterson, Erik H; Johnson, Bruce D; Borlaug, Barry A; Olson, Thomas P

    2017-12-01

    Patients with heart failure (HF) with reduced (HFrEF) or preserved (HFpEF) ejection fraction demonstrate an increased ventilatory equivalent for carbon dioxide (V̇ E /V̇CO 2 ) slope. The physiological correlates of the V̇ E /V̇CO 2 slope remain unclear in the two HF phenotypes. We hypothesized that changes in the physiological dead space to tidal volume ratio (V D /V T ) and arterial CO 2 tension (PaCO 2 ) differentially contribute to the V̇ E /V̇CO 2 slope in HFrEF vs. HFpEF. Adults with HFrEF (n = 32) and HFpEF (n = 27) [mean ± standard deviation (SD) left ventricular ejection fraction: 22 ± 7% and 61 ± 9%, respectively; mean ± SD body mass index: 28 ± 4 kg/m 2 and 33 ± 6 kg/m 2 , respectively; P breath-by-breath ventilation and gas exchange measurements. PaCO 2 was measured via radial arterial catheterization. We calculated the V̇ E /V̇CO 2 slope via linear regression, and V D /V T  = 1 - [(863 × V̇CO 2 )/(V̇ E  × PaCO 2 )]. Resting V D /V T (0.48 ± 0.08 vs. 0.41 ± 0.11; P = 0.04), but not PaCO 2 (38 ± 5 mmHg vs. 40 ± 3 mmHg; P = 0.21) differed between HFrEF and HFpEF. Peak exercise V D /V T (0.39 ± 0.08 vs. 0.32 ± 0.12; P = 0.02) and PaCO 2 (33 ± 6 mmHg vs. 38 ± 4 mmHg; P < 0.01) differed between HFrEF and HFpEF. The V̇ E /V̇CO 2 slope was higher in HFrEF compared with HFpEF (44 ± 11 vs. 35 ± 8; P < 0.01). Variance associated with the V̇ E /V̇CO 2 slope in HFrEF and HFpEF was explained by peak exercise V D /V T (R 2  = 0.30 and R 2  = 0.50, respectively) and PaCO 2 (R 2  = 0.64 and R 2  = 0.28, respectively), but the relative contributions of each differed (all P < 0.01). Relationships between the V̇ E /V̇CO 2 slope and both V D /V T and PaCO 2 are robust, but differ between HFpEF and HFrEF. Increasing V̇ E /V̇CO 2 slope appears to be strongly explained by mechanisms influential in

  6. Highly ordered three-dimensional macroporous carbon spheres for determination of heavy metal ions

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yuxiao; Zhang, Jianming [Institute of Functional Nano and Soft Materials (FUNSOM) and Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Soochow University, Suzhou 215123 (China); Liu, Yang, E-mail: yangl@suda.edu.cn [Institute of Functional Nano and Soft Materials (FUNSOM) and Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Soochow University, Suzhou 215123 (China); Huang, Hui [Institute of Functional Nano and Soft Materials (FUNSOM) and Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Soochow University, Suzhou 215123 (China); Kang, Zhenhui, E-mail: zhkang@suda.edu.cn [Institute of Functional Nano and Soft Materials (FUNSOM) and Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Soochow University, Suzhou 215123 (China)

    2012-04-15

    Highlights: Black-Right-Pointing-Pointer Highly ordered three dimensional macroporous carbon spheres (MPCSs) were prepared. Black-Right-Pointing-Pointer MPCS was covalently modified by cysteine (MPCS-CO-Cys). Black-Right-Pointing-Pointer MPCS-CO-Cys was first time used in electrochemical detection of heavy metal ions. Black-Right-Pointing-Pointer Heavy metal ions such as Pb{sup 2+} and Cd{sup 2+} can be simultaneously determined. -- Abstract: An effective voltammetric method for detection of trace heavy metal ions using chemically modified highly ordered three dimensional macroporous carbon spheres electrode surfaces is described. The highly ordered three dimensional macroporous carbon spheres were prepared by carbonization of glucose in silica crystal bead template, followed by removal of the template. The highly ordered three dimensional macroporous carbon spheres were covalently modified by cysteine, an amino acid with high affinities towards some heavy metals. The materials were characterized by physical adsorption of nitrogen, scanning electron microscopy, and transmission electron microscopy techniques. While the Fourier-transform infrared spectroscopy was used to characterize the functional groups on the surface of carbon spheres. High sensitivity was exhibited when this material was used in electrochemical detection (square wave anodic stripping voltammetry) of heavy metal ions due to the porous structure. And the potential application for simultaneous detection of heavy metal ions was also investigated.

  7. Highly ordered three-dimensional macroporous carbon spheres for determination of heavy metal ions

    International Nuclear Information System (INIS)

    Zhang, Yuxiao; Zhang, Jianming; Liu, Yang; Huang, Hui; Kang, Zhenhui

    2012-01-01

    Highlights: ► Highly ordered three dimensional macroporous carbon spheres (MPCSs) were prepared. ► MPCS was covalently modified by cysteine (MPCS–CO–Cys). ► MPCS–CO–Cys was first time used in electrochemical detection of heavy metal ions. ► Heavy metal ions such as Pb 2+ and Cd 2+ can be simultaneously determined. -- Abstract: An effective voltammetric method for detection of trace heavy metal ions using chemically modified highly ordered three dimensional macroporous carbon spheres electrode surfaces is described. The highly ordered three dimensional macroporous carbon spheres were prepared by carbonization of glucose in silica crystal bead template, followed by removal of the template. The highly ordered three dimensional macroporous carbon spheres were covalently modified by cysteine, an amino acid with high affinities towards some heavy metals. The materials were characterized by physical adsorption of nitrogen, scanning electron microscopy, and transmission electron microscopy techniques. While the Fourier-transform infrared spectroscopy was used to characterize the functional groups on the surface of carbon spheres. High sensitivity was exhibited when this material was used in electrochemical detection (square wave anodic stripping voltammetry) of heavy metal ions due to the porous structure. And the potential application for simultaneous detection of heavy metal ions was also investigated.

  8. Low-carbohydrate diets reduce lipid accumulation and arterial inflammation in guinea pigs fed a high-cholesterol diet.

    Science.gov (United States)

    Leite, Jose O; DeOgburn, Ryan; Ratliff, Joseph; Su, Randy; Smyth, Joan A; Volek, Jeff S; McGrane, Mary M; Dardik, Alan; Fernandez, Maria Luz

    2010-04-01

    Low-carbohydrate diets (LCD) efficiently induce weight loss and favorably affect plasma lipids, however, the effect of LCD on atherosclerosis is still argued. To evaluate the effect of LCD on the prevention of atherosclerosis. Twenty guinea pigs were fed either a LCD or a low-fat diet (LFD) in combination with high-cholesterol (0.25g/100g) for 12 weeks. The percentage energy of macronutrient distribution was 10:65:25 for carbohydrate:fat:protein for the LCD, and 55:20:25 for the LFD. Plasma lipids were measured using colorimetric assays. Plasma and aortic oxidized (oxLDL) were quantified using ELISA methods. Inflammatory cytokines were measured in aortic homogenates using an immunoassay. H&E stained sections of aortic sinus and Schultz stained sections of carotid arteries were examined. LDL cholesterol was lower in the LCD compared to the LFD group (71.9+/-34.8 vs. 81.7+/-26.9mg/dL; p=0.039). Aortic cholesterol was also lower in the LCD (4.98+/-1.3mg/g) compared to the LFD group (6.68+/-2.0mg/g); p<0.05. The Schultz staining method confirmed less aortic cholesterol accumulation in the LCD group. Plasma oxLDL did not differ between groups, however, aortic oxLDL was 61% lower in the LCD compared to the LFD group (p=0.045). There was a positive correlation (r=0.63, p=0.03) between oxLDL and cholesterol concentration in the aorta of LFD group, which was not observed in LCD group (r=-0.05, p=0.96). Inflammatory markers were reduced in guinea pigs from the LCD group (p<0.05) and they were correlated with the decreases in oxLDL in aorta. These results suggest that LCD not only decreases lipid deposition, but also prevents the accumulation of oxLDL and reduces inflammatory cytokines within the arterial wall and may prevent atherosclerosis. Copyright 2009 Elsevier Ireland Ltd. All rights reserved.

  9. 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. Copyright © 2012 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.

  10. 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.

  11. Persistent cyclestability of carbon coated Zn–Sn metal oxide/carbon microspheres as highly reversible anode material for lithium-ion batteries

    International Nuclear Information System (INIS)

    Fang, Guoqing; Kaneko, Shingo; Liu, Weiwei; Xia, Bingbo; Sun, Hongdan; Zhang, Ruixue; Zheng, Junwei; Li, Decheng

    2013-01-01

    Development of high-capacity anode materials equipped with strong cyclestability is a great challenge for use as practical electrode for high-performance lithium-ion rechargeable battery. In this study, we synthesized a carbon coated Zn–Sn metal nanocomposite oxide and carbon spheres (ZTO@C/CSs) via a simple glucose hydrothermal reaction and subsequent carbonization approach. The carbon coated ZTO/carbon microspheres composite maintained a reversible capacity of 680 mAh g −1 after 345 cycles at a current density of 100 mA g −1 , and furthermore the cell based on the composite exhibited an excellent rate capability of 470 mAh g −1 even when the cell was cycled at 2000 mA g –1 . The thick carbon layer formed on the ZTO nanoparticles and carbon spheres effectively buffered the volumetric change of the particles, which thus prolonged the cycling performance of the electrodes

  12. Percutaneous closure of patent arterial ducts in patients from high altitude: a sub-Saharan experience

    Directory of Open Access Journals (Sweden)

    Endale Tefera

    2015-01-01

    Conclusions: Successful duct closure was achieved in the vast majority of patients, even though the ducts were larger and significant number of them had pulmonary hypertension in this high altitude group. There was a relatively higher incidence of residual shunts and device migration in this series, generally due to the nonavailability of optimal device and surgical support. Long-term follow-up is required before we can draw conclusions with regard to the sustainability of drop in PA pressures. Septal Occluder devices may be a possible alternative for large tubular or window-type ducts with severe pulmonary hypertension, where there may be concerns about the size and stability of duct occluder devices.

  13. High-Definition Computed Tomography for Coronary Artery Stent Imaging: a Phantom Study

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Wen Jie; Chen, Ke Min; Pang, Li Fang; Zhang, Huang; Pan, Zi Lai [Rui Jin Hospital, Medical School, Shanghai Jiao Tong University, Shangha (China); Guo, Ying; Li, Jian Ying [Beijing Economic and Technology Development Area, Beijing (China)

    2012-01-15

    To assess the performance of a high-definition CT (HDCT) for imaging small caliber coronary stents ({<=} 3 mm) by comparing different scan modes of a conventional 64-row standard-definition CT (SDCT). A cardiac phantom with twelve stents (2.5 mm and 3.0 mm in diameter) was scanned by HDCT and SDCT. The scan modes were retrospective electrocardiography (ECG)-gated helical and prospective ECG-triggered axial with tube voltages of 120 kVp and 100 kVp, respectively. The inner stent diameters (ISD) and the in-stent attenuation value (AVin-stent) and the in-vessel extra-stent attenuation value (AVin-vessel) were measured by two observers. The artificial lumen narrowing (ALN = [ISD - ISDmeasured]/ISD) and artificial attenuation increase between in-stent and in-vessel (AAI = AVin-stent - AVin-vessel) were calculated. All data was analyzed by intraclass correlation and ANOVA-test. The correlation coefficient of ISD, AVin-vessel and AVin-stent between the two observers was good. The ALNs of HDCT were statistically lower than that of SDCT (30 {+-} 5.7% versus 35 {+-} 5.4%, p < 0.05). HDCT had statistically lower AAI values than SDCT (15.7 {+-} 81.4 HU versus 71.4 {+-} 90.5 HU, p < 0.05). The prospective axial dataset demonstrated smaller ALN than the retrospective helical dataset on both HDCT and SDCT (p < 0.05). Additionally, there were no differences in ALN between the 120 kVp and 100 kVp tube voltages on HDCT (p = 0.05). High-definition CT helps improve measurement accuracy for imaging coronary stents compared to SDCT. HDCT with 100 kVp and the prospective ECG-triggered axial technique, with a lower radiation dose than 120 kVp application, may be advantageous in evaluating coronary stents with smaller calibers ({<=} 3 mm).

  14. High-performance radio frequency transistors based on diameter-separated semiconducting carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Cao, Yu; Che, Yuchi; Zhou, Chongwu, E-mail: chongwuz@usc.edu [Department of Electrical Engineering, University of Southern California, Los Angeles, California 90089 (United States); Seo, Jung-Woo T.; Hersam, Mark C. [Department of Materials Science and Engineering and Department of Chemistry, Northwestern University, Evanston, Illinois 60208 (United States); Gui, Hui [Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, California 90089 (United States)

    2016-06-06

    In this paper, we report the high-performance radio-frequency transistors based on the single-walled semiconducting carbon nanotubes with a refined average diameter of ∼1.6 nm. These diameter-separated carbon nanotube transistors show excellent transconductance of 55 μS/μm and desirable drain current saturation with an output resistance of ∼100 KΩ μm. An exceptional radio-frequency performance is also achieved with current gain and power gain cut-off frequencies of 23 GHz and 20 GHz (extrinsic) and 65 GHz and 35 GHz (intrinsic), respectively. These radio-frequency metrics are among the highest reported for the carbon nanotube thin-film transistors. This study provides demonstration of radio frequency transistors based on carbon nanotubes with tailored diameter distributions, which will guide the future application of carbon nanotubes in radio-frequency electronics.

  15. High-flux water desalination with interfacial salt sieving effect in nanoporous carbon composite membranes

    Science.gov (United States)

    Chen, Wei; Chen, Shuyu; Liang, Tengfei; Zhang, Qiang; Fan, Zhongli; Yin, Hang; Huang, Kuo-Wei; Zhang, Xixiang; Lai, Zhiping; Sheng, Ping

    2018-04-01

    Freshwater flux and energy consumption are two important benchmarks for the membrane desalination process. Here, we show that nanoporous carbon composite membranes, which comprise a layer of porous carbon fibre structures grown on a porous ceramic substrate, can exhibit 100% desalination and a freshwater flux that is 3-20 times higher than existing polymeric membranes. Thermal accounting experiments demonstrated that the carbon composite membrane saved over 80% of the latent heat consumption. Theoretical calculations combined with molecular dynamics simulations revealed the unique microscopic process occurring in the membrane. When the salt solution is stopped at the openings to the nanoscale porous channels and forms a meniscus, the vapour can rapidly transport across the nanoscale gap to condense on the permeate side. This process is driven by the chemical potential gradient and aided by the unique smoothness of the carbon surface. The high thermal conductivity of the carbon composite membrane ensures that most of the latent heat is recovered.

  16. High resolution analysis of tropical forest fragmentation and its impact on the global carbon cycle

    Science.gov (United States)

    Brinck, Katharina; Fischer, Rico; Groeneveld, Jürgen; Lehmann, Sebastian; Dantas de Paula, Mateus; Pütz, Sandro; Sexton, Joseph O.; Song, Danxia; Huth, Andreas

    2017-03-01

    Deforestation in the tropics is not only responsible for direct carbon emissions but also extends the forest edge wherein trees suffer increased mortality. Here we combine high-resolution (30 m) satellite maps of forest cover with estimates of the edge effect and show that 19% of the remaining area of tropical forests lies within 100 m of a forest edge. The tropics house around 50 million forest fragments and the length of the world's tropical forest edges sums to nearly 50 million km. Edge effects in tropical forests have caused an additional 10.3 Gt (2.1-14.4 Gt) of carbon emissions, which translates into 0.34 Gt per year and represents 31% of the currently estimated annual carbon releases due to tropical deforestation. Fragmentation substantially augments carbon emissions from tropical forests and must be taken into account when analysing the role of vegetation in the global carbon cycle.

  17. High-flux water desalination with interfacial salt sieving effect in nanoporous carbon composite membranes

    KAUST Repository

    Chen, Wei

    2018-03-05

    Freshwater flux and energy consumption are two important benchmarks for the membrane desalination process. Here, we show that nanoporous carbon composite membranes, which comprise a layer of porous carbon fibre structures grown on a porous ceramic substrate, can exhibit 100% desalination and a freshwater flux that is 3-20 times higher than existing polymeric membranes. Thermal accounting experiments demonstrated that the carbon composite membrane saved over 80% of the latent heat consumption. Theoretical calculations combined with molecular dynamics simulations revealed the unique microscopic process occurring in the membrane. When the salt solution is stopped at the openings to the nanoscale porous channels and forms a meniscus, the vapour can rapidly transport across the nanoscale gap to condense on the permeate side. This process is driven by the chemical potential gradient and aided by the unique smoothness of the carbon surface. The high thermal conductivity of the carbon composite membrane ensures that most of the latent heat is recovered.

  18. 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.

  19. Highly conductive interwoven carbon nanotube and silver nanowire transparent electrodes

    Directory of Open Access Journals (Sweden)

    Andrew J Stapleton, Rakesh A Afre, Amanda V Ellis, Joe G Shapter, Gunther G Andersson, Jamie S Quinton and David A Lewis

    2013-01-01

    Full Text Available Electrodes fabricated using commercially available silver nanowires (AgNWs and single walled carbon nanotubes (SWCNTs produced sheet resistances in the range 4–24 Ω squ−1 with specular transparencies up to 82 %. Increasing the aqueous dispersibility of SWCNTs decreased the bundle size present in the film resulting in improved SWCNT surface dispersion in the films without compromising transparency or sheet resistance. In addition to providing conduction pathways between the AgNW network, the SWCNTs also provide structural support, creating stable self-supporting films. Entanglement of the AgNWs and SWCNTs was demonstrated to occur in solution prior to deposition by monitoring the transverse plasmon resonance mode of the AgNWs during processing. The interwoven AgNW/SWCNT structures show potential for use in optoelectronic applications as transparent electrodes and as an ITO replacement.

  20. High-resolution optical microscopy of carbon and graphite

    International Nuclear Information System (INIS)

    Cook, W.H.; Allen, M.D.; Leslie, B.C.; Gray, R.J.

    1975-01-01

    The ceramographic preparation of carbonaceous materials varying in crystalline quality, amorphous carbon to well crystallized graphite, is described. In a two-step process, using alumina and diamond polishing compounds, one can prepare more samples, obtain a substantial saving in man hours, avoid rounding material around pores, and obtain flatter surfaces than were obtainable with earlier, conventional methods. Improved resolution of microstructural details is achieved without impregnation with epoxy resins or other materials to support the porous structures. Use of rotatable, half-wave retardation (sensitive tint) enhances the microstructural definition in both color and black and white. These innovations were extensively used as part of the examination of nuclear grades of graphite before and after exposure to fast neutrons at temperatures from 650 to 1100 0 C; typical examples are discussed. (auth)

  1. Arterial carboxyhemoglobin level and outcome in critically ill patients.

    Science.gov (United States)

    Melley, Daniel D; Finney, Simon J; Elia, Androula; Lagan, Anna L; Quinlan, Gregory J; Evans, Timothy W

    2007-08-01

    Arterial carboxyhemoglobin is elevated in patients with critical illness. It is an indicator of the endogenous production of carbon monoxide by the enzyme heme oxygenase, which modulates the response to oxidant stress. The objective was to explore the hypothesis that arterial carboxyhemoglobin level is associated with inflammation and survival in patients requiring cardiothoracic intensive care. Prospective, observational study. A cardiothoracic intensive care unit. All patients admitted over a 15-month period. None. Arterial carboxyhemoglobin, bilirubin, and standard biochemical, hematologic, and physiologic markers of inflammation were measured in 1,267 patients. Associations were sought between levels of arterial carboxyhemoglobin, markers of the inflammatory response, and clinical outcome. Intensive care unit mortality was associated with lower minimum and greater maximal carboxyhemoglobin levels (p carboxyhemoglobin was associated with an increased risk of death from all causes (odds risk of death, 0.391; 95% confidence interval, 0.190-0.807; p = .011). Arterial carboxyhemoglobin correlated with markers of the inflammatory response. Both low minimum and high maximum levels of arterial carboxyhemoglobin were associated with increased intensive care mortality. Although the heme oxygenase system is protective, excessive induction may be deleterious. This suggests that there may be an optimal range for heme oxygenase-1 induction.

  2. Measurements of Carbon Dioxide and Carbon Monoxide at High Spatial and Temporal Resolution in an Urban Environment

    Science.gov (United States)

    Rella, C.; Jacobson, G. A.; Crosson, E.

    2011-12-01

    The ability to take inventory of critical greenhouse gases such as carbon dioxide and methane and quantify their sources and sinks is essential for understanding the atmospheric drivers to global climate change. "Top down" inversion measurements and models are used to quantify net carbon fluxes into the atmosphere. The overall carbon fluxes are determined by combining remote measurements of carbon dioxide concentrations with complex atmospheric transport models, and these emissions measurements are compared to "bottoms-up" predictions based on detailed inventories of the sources and sinks of carbon, both anthropogenic and biogenic in nature. At smaller distance scales, such as that of a city or even smaller, the basic framework underpinning the inversion modeling technique begins to break down: atmospheric transport models, which are well understood at a length scale of 100 km, work poorly or not at all at a 100m distance scale. Furthermore, the variability of the emissions sources in space (e.g., factories, highways, residences) and time (rush hours, factory shifts and shutdowns, residential energy usage variability during the day and over the year) complicate the interpretation of the measured signals. In this paper we present detailed, high spatial- and temporal-resolution greenhouse gas measurements in Silicon Valley, CA. The results of two experimental campaigns are presented: a 10m urban 'tower' and ground-based mobile mapping measurements. In both campaigns, real-time carbon dioxide data are combined with real-time carbon monoxide measurements to partition the observed CO2 concentrations between anthropogenic and biogenic sources . The urban tower measurements are made continuously over a period of many weeks. The mobile maps of the vicinity of the urban tower are taken repeatedly over a period of several days, and at different times of the day and under different atmospheric conditions, to assess the robustness and repeatability of the maps. Initial

  3. Polyfurfuryl alcohol derived activated carbons for high power electrical double layer capacitors

    Energy Technology Data Exchange (ETDEWEB)

    Ruiz, V. [CSIRO Division of Energy Technology, Box 312, Clayton South, Vic. 3169 (Australia); Pandolfo, A.G., E-mail: tony.pandolfo@csiro.a [CSIRO Division of Energy Technology, Box 312, Clayton South, Vic. 3169 (Australia)

    2010-10-30

    Polyfurfuryl alcohol (PFA) derived activated carbons were prepared by the acid catalysed polymerization of furfuryl alcohol, followed by potassium hydroxide activation. Activated carbons with apparent BET surface areas ranging from 1070 to 2600 m{sup 2} g{sup -1}, and corresponding average micropore sizes between 0.6 and 1.6 nm were obtained. The porosity of these carbons can be carefully controlled during activation and their performance as electrode materials in electric double layer capacitors (EDLCs) in a non-aqueous electrolyte (1 M Et{sub 4}NBF{sub 4}/ACN) is investigated. Carbon materials with a low average pore size (<{approx}0.6 nm) exhibited electrolyte accessibility issues and an associated decrease in capacitance at high charging rates. PFA carbons with larger average pore sizes exhibited greatly improved performance, with specific electrode capacitances of 150 F g{sup -1} at an operating voltage window of 0-2.5 V; which corresponds to 32 Wh kg{sup -1} and 38 kW kg{sup -1} on an active material basis. These carbons also displayed an outstanding performance at high current densities delivering up to 100 F g{sup -1} at current densities as high as 250 A g{sup -1}. The exceptionally high capacitance and power of this electrode material is attributed to its good electronic conductivity and a highly effective combination of micro- and fine mesoporosity.

  4. 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.

  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. Carbon nanotubes/cobalt sulfide composites as potential high-rate and high-efficiency supercapacitors

    Science.gov (United States)

    Chen, Chia-Ying; Shih, Zih-Yu; Yang, Zusing; Chang, Huan-Tsung

    2012-10-01

    We have prepared carbon nanotube (CNT)/cobalt sulfide (CoS) composites from cobalt nitrate, thioacetamide, and CNTs in the presence of poly(vinylpyrrolidone). CNT/CoS composites are deposited onto fluorine-doped tin oxide glass substrates and then subjected to simple annealing at 300 °C for 0.5 h to fabricate CNT/CoS electrodes. Data collected from Raman spectroscopy, X-ray photoelectron spectroscopy, high-resolution transmission electron microscopy, and d-spacing reveal the changes in the CoS structures and crystalline lattices after annealing. Cyclic voltammetry results reveal that the annealed CNT/CoS composite electrodes yield values of 2140 ± 90 and 1370 ± 50 F g-1 for specific capacitance at scan rates of 10 and 100 mV s-1, respectively. To the best of our knowledge, the annealed CNT/CoS composite electrodes provide higher specific capacitance relative to other reported ones at a scan rate of 100 mV s-1. CNT/CoS composite electrodes yield a power density of 62.4 kW kg-1 at a constant discharge current density of 217.4 A g-1. With such a high-rate capacity and power density, CNT/CoS composite supercapacitors demonstrate great potential as efficient energy storage devices.

  7. 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.

  8. Arterial stick

    Science.gov (United States)

    ... be some throbbing. Why the Test Is Performed Blood transports oxygen, nutrients, waste products, and other materials within ... venous blood) mainly in its content of dissolved gases . Testing arterial blood shows the makeup of the blood before any ...

  9. Estimates of Carbon Reservoirs in High-Altitude Wetlands in the Colombian Andes

    Directory of Open Access Journals (Sweden)

    Enrique Javier Peña

    2009-10-01

    Full Text Available The observed increase in emission of greenhouse gases, with attendant effects on global warming, have raised interests in identifying sources and sinks of carbon in the environment. Terrestrial carbon (C sequestration involves capture of atmospheric C through photosynthesis and storage in biota, soil and wetlands. Particularly, wetland systems function primarily as long-term reservoirs for atmospheric carbon dioxide (CO2 and as sources of atmospheric methane (CH4. The objective of this study was to evaluate the patterns of carbon reservoirs in two high-altitude wetlands in the central Andean mountain of Colombia. Carbon cycle in both systems is related mainly with the plant biomass dynamics from the littoral zone. Thus, total organic carbon concentrate an average up to 329 kg of N ha-1 and 125 kg of P ha-1 every year vs only 17 kg N ha-1 and 6 kg P ha-1 in the water column of the limnetic zone in the wetland, evidencing spatial differences in carbon concentrations for these types of ecosystems. Results revealed that these systems participate in the balance and sequestration of carbon in the Colombian Andes.

  10. Activated carbon derived from chitosan as air cathode catalyst for high performance in microbial fuel cells

    Science.gov (United States)

    Liu, Yi; Zhao, Yong; Li, Kexun; Wang, Zhong; Tian, Pei; Liu, Di; Yang, Tingting; Wang, Junjie

    2018-02-01

    Chitosan with rich of nitrogen is used as carbon precursor to synthesis activated carbon through directly heating method in this study. The obtained carbon is activated by different amount of KOH at different temperatures, and then prepared as air cathodes for microbial fuel cells. Carbon sample treated with double amount of KOH at 850 °C exhibits maximum power density (1435 ± 46 mW m-2), 1.01 times improved, which ascribes to the highest total surface area, moderate micropore and mesoporous structure and the introduction of nitrogen. The electrochemical impedance spectroscopy and powder resistivity state that carbon treated with double amount of KOH at 850 °C possesses lower resistance. The other electrochemical measurements demonstrate that the best kinetic activity make the above treated sample to show the best oxygen reduction reaction activity. Besides, the degree of graphitization of samples increases with the activated temperature increasing, which is tested by Raman. According to elemental analysis and X-ray photoelectron spectroscopy, all chitosan samples are nitrogen-doped carbon, and high content nitrogen (pyridinic-N) improves the electrochemical activity of carbon treated with KOH at 850 °C. Thus, carbon materials derived from chitosan would be an optimized catalyst for oxygen reduction reaction in microbial fuel cell.

  11. Large-deformation and high-strength amorphous porous carbon nanospheres

    Science.gov (United States)

    Yang, Weizhu; Mao, Shimin; Yang, Jia; Shang, Tao; Song, Hongguang; Mabon, James; Swiech, Wacek; Vance, John R.; Yue, Zhufeng; Dillon, Shen J.; Xu, Hangxun; Xu, Baoxing

    2016-04-01

    Carbon is one of the most important materials extensively used in industry and our daily life. Crystalline carbon materials such as carbon nanotubes and graphene possess ultrahigh strength and toughness. In contrast, amorphous carbon is known to be very brittle and can sustain little compressive deformation. Inspired by biological shells and honeycomb-like cellular structures in nature, we introduce a class of hybrid structural designs and demonstrate that amorphous porous carbon nanospheres with a thin outer shell can simultaneously achieve high strength and sustain large deformation. The amorphous carbon nanospheres were synthesized via a low-cost, scalable and structure-controllable ultrasonic spray pyrolysis approach using energetic carbon precursors. In situ compression experiments on individual nanospheres show that the amorphous carbon nanospheres with an optimized structure can sustain beyond 50% compressive strain. Both experiments and finite element analyses reveal that the buckling deformation of the outer spherical shell dominates the improvement of strength while the collapse of inner nanoscale pores driven by twisting, rotation, buckling and bending of pore walls contributes to the large deformation.

  12. Erosion of pyrolytic carbon under high surface energy deposition from a pulsed hydrogen plasma

    International Nuclear Information System (INIS)

    Bolt, H.

    1992-01-01

    Carbon materials are widely applied as plasma facing materials in nuclear fusion devices and are also the prime candidate materials for the next generation of experimental fusion reactors. During operation these materials are frequently subjected to high energy deposition from plasma disruptions. The erosion of carbon materials is regarded as the main issue governing the operational lifetime of plasma facing components. Laboratory experiments have been performed to study the thermal erosion behaviour of carbon in a plasma environment. In the experiments the surface of pyrolytic carbon specimens was exposed to pulsed energy deposition of up to 3.8 MJ m -2 from a hydrogen plasma. The behaviour of the eroded carbon species in the plasma was measured by time-resolved and space-resolved spectroscopy. Intense line radiation of ionic carbon has been measured in the plasma in front of the carbon surface. The results show that the eroded carbon is immediately ionised in the vicinity of the material surface, with a fraction of it being ionised to the double-charged state. (Author)

  13. Evidence of arterial wall uptake of fluorodeoxyglucose on imaging can indicate recent or future cardiovascular events in high-risk patients

    International Nuclear Information System (INIS)

    Paulmier, B.; Khayat, R.; Duet, M.; Pierquet-Ghazzar, N.; Maunoury, C.; Sauvaget, E.; Faraggi, M.; Laissy, J.P.

    2007-01-01

    With this study, we sought to identify plaque inflammation as assessed by 18 FDG uptake on positron emission tomography (PET)/computed tomography (CT) as an independent cardiovascular risk factor in patients at high risk for cardiovascular events. We compared 31 consecutive cancer patients presenting with visually enhanced 18 FDG uptake in arterial walls on PET/CT (Group 1) to a selection of 34 matched cancer patients not showing arterial uptake (Group 2). All patients were followed for two years before and six months after PET/CT... Cardiovascular events were classified as older (>6 months before PET/CT) or recent ( 18 FDG uptake was computed on non-attenuation corrected data by a AW/L ratio: mean Arterial Wall uptake/Lung uptake in a normal area, and by SUV on corrected data. A calcium score (CS) was also calculated. 18 FDG uptake and CS were higher in Group 1 than Group 2 (both p = 0.02), and older and recent cardiovascular events were significantly more frequent in Group 1 than Group 2 (p = 0.001 and p = 0.03. respectively). Among the following parameters: number of conventional risk factor, calcium score and presence of 18 FDG uptake, only the latter was significantly related to the occurrence of a recent event by multivariate analysis (p = 0.02). Patients with elevated arterial 18 FDG uptake have a high risk of immediate or future cardiovascular events. Arterial 18 FDG uptake is an indicator of evolving atherosclerotic process and can indicate future cardiovascular events. (authors)

  14. 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

  15. The effects of carbon nano filaments (CNT and CNF) doping on high temperature superconductors Y-123

    International Nuclear Information System (INIS)

    Dadras, S.; Daadmehr, V.

    2007-01-01

    Full text: This paper is based on the effects of carbon nano filaments (carbon nano tubes and carbon nano fibers) doping on Y-123 studies. We synthesized Y-123 with different contents of CNT and CNF doping. The samples were prepared from powders of Y 2 O 3 , BaCO 3 and Cu O by the solid state reaction. After calcination in air, we mixed Y-123 powder with different percentage of carbon nano filaments weight, produced by the CVD method. For obtaining more homogenous mixing, we have suspended it in an organic solvent with an ultrasonic mixer to prevent agglomeration of CNT. The CNT-Y-123 powder was dried afterwards, and pressed as pellet samples, in about 1mm thick, 10mm diameter, and 1gr weight, and sintered in oxygen atmosphere. We tried to find the transport effects on CNT and CNF doping in 123 systems. The strong coupling between grains in CNT doped samples caused the flow of inter-granular currents. Therefore the presence of CNT in high temperature superconductor samples increases the critical current density. Among various carbon precursors, carbon nano tubes (CNT) are very interesting because of their nano meter diameter which may make them as effective pinning centers, compared to the ordinary carbon. The carbon nano tubes are functioning like columnar defects produced by heavy-ion irradiation. Nano phase particles or aggregates embodied in the superconductor matrix can pin the flux lines effectively and enhance the intra-grain transport critical current density in high applied magnetic fields. Nano phase size particles in the size range of about 5-10 nm can be used as flux pinning centers for low field applications. The effects of carbon and carbon dioxide in Y-123 were studied by several groups, but none of them argued the effects of carbon nano tubes doping on Y-123. Uno et al. found that Jc was related to the carbon concentration, but they showed that Tc value and other physical properties did not change. In carbon doped Y-123 samples, Tc decreases with

  16. High-Density Lipoproteins-Associated Proteins and Subspecies Related to Arterial Stiffness in Young Adults with Type 2 Diabetes Mellitus

    Directory of Open Access Journals (Sweden)

    Xiaoting Zhu

    2018-01-01

    Full Text Available Lower plasma levels of high-density lipoproteins (HDL in adolescents with type 2 diabetes (T2D have been associated with a higher pulse wave velocity (PWV, a marker of arterial stiffness. Evidence suggests that HDL proteins or particle subspecies are altered in T2D and these may drive these relationships. In this work, we set out to reveal any specific proteins and subspecies that are related to arterial stiffness in youth with T2D from proteomics data. Plasma and PWV measurements were previously acquired from lean and T2D adolescents. Each plasma sample was separated into 18 fractions and evaluated by mass spectrometry. Then, we applied a validated network-based computational approach to reveal HDL subspecies associated with PWV. Among 68 detected phospholipid-associated proteins, we found that seven were negatively correlated with PWV, indicating that they may be atheroprotective. Conversely, nine proteins show positive correlation with PWV, suggesting that they may be related to arterial stiffness. Intriguingly, our results demonstrate that apoA-I and histidine-rich glycoprotein may reverse their protective roles and become antagonistic in the setting of T2D. Furthermore, we revealed two arterial stiffness-associated HDL subspecies, each of which contains multiple PWV-related proteins. Correlation and disease association analyses suggest that these HDL subspecies might link T2D to its cardiovascular-related complications.

  17. Low pulmonary artery flush perfusion pressure combined with high positive end-expiratory pressure reduces oedema formation in isolated porcine lungs

    International Nuclear Information System (INIS)

    Schumann, Stefan; Schließmann, Stephan J; Wagner, Giskard; Goebel, Ulrich; Priebe, Hans-Joachim; Guttmann, Josef; Kirschbaum, Andreas

    2010-01-01

    Flush perfusion of the pulmonary artery with organ protection solution is a standard procedure before lung explantation. However, rapid flush perfusion may cause pulmonary oedema which is deleterious in the lung transplantation setting. In this study we tested the hypotheses that high pulmonary perfusion pressure contributes to the development of pulmonary oedema and positive end-expiratory pressure (PEEP) counteracts oedema formation. We expected oedema formation to increase weight and decrease compliance of the lungs on the basis of a decrease in alveolar volume as fluid replaces alveolar air spaces. The pulmonary artery of 28 isolated porcine lungs was perfused with a low-potassium dextrane solution at low (mean 27 mmHg) or high (mean 40 mmHg) pulmonary artery pressure (PAP) during mechanical ventilation at low (4 cmH 2 O) or high (8 cmH 2 O) PEEP, respectively. Following perfusion and storage, relative increases in lung weight were smaller (p < 0.05) during perfusion at low PAP (62 ± 32% and 42 ± 26%, respectively) compared to perfusion at high PAP (133 ± 54% and 87 ± 30%, respectively). Compared to all other PAP–PEEP combinations, increases in lung weight were smallest (44 ± 9% and 27 ± 12%, respectively), nonlinear intratidal lung compliance was largest (46% and 17% respectively, both p < 0.05) and lung histology showed least infiltration of mononuclear cells in the alveolar septa, and least alveolar destruction during the combination of low perfusion pressure and high PEEP. The findings suggest that oedema formation during pulmonary artery flush perfusion in isolated and ventilated lungs can be reduced by choosing low perfusion pressure and high PEEP. PAP–PEEP titration to minimize pulmonary oedema should be based on lung mechanics and PAP monitoring

  18. Differentiation of deep subcortical infarction using high-resolution vessel wall MR imaging of middle cerebral artery

    Energy Technology Data Exchange (ETDEWEB)

    Bae, Yun Jung; Choi, Byung Se; Jung, Cheol Kyu; Yoon, Yeon Hong; Sunwoo, Leonard; Kim, Jae Hyoung; Bae, Hee Joon [Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam (Korea, Republic of)

    2017-11-15

    To evaluate the utility of high-resolution vessel wall imaging (HR-VWI) of middle cerebral artery (MCA), and to compare HR-VWI findings between striatocapsular infarction (SC-I) and lenticulostriate infarction (LS-I). This retrospective study was approved by the Institutional Review Board, and informed consent was waived. From July 2009 to February 2012, 145 consecutive patients with deep subcortical infarctions (SC-I, n = 81; LS-I, n = 64) who underwent HR-VWI were included in this study. The degree of MCA stenosis and the characteristics of MCA plaque (presence, eccentricity, location, extent, T2-high signal intensity [T2-HSI], and plaque enhancement) were analyzed, and compared between SC-I and LS-I, using Fisher's exact test. Stenosis was more severe in SC-I than in LS-I (p = 0.040). MCA plaque was more frequent in SC-I than in LS-I (p = 0.028), having larger plaque extent (p = 0.001), more T2-HSI (p = 0.001), and more plaque enhancement (p = 0.002). The eccentricity and location of the plaque showed no significant difference between the two groups.Both SC-I and LS-I have similar HR-VWI findings of the MCA plaque, but SC-I had more frequent, larger plaques with greater T2-HSI and enhancement. This suggests that HR-VWI may have a promising role in assisting the differentiation of underlying pathophysiological mechanism between SC-I and LS-I.

  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. 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.

  1. Economic Evaluations for the Carbon Dioxide-involved Production of High-value Chemicals

    International Nuclear Information System (INIS)

    Lee, Ji Hyun; Lee, Dong Woog; Jang, Se Gyu; Kwak, No-Sang; Lee, In Young; Jang, Kyung Ryoung; Shim, Jae-Goo; Choi, Jong Shin

    2014-01-01

    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

  2. Environmental variation, vegetation distribution, carbon dynamics and water/energy exchange at high latitudes

    Science.gov (United States)

    McGuire, A.D.; Wirth, C.; Apps, M.; Beringer, J.; Clein, J.; Epstein, H.; Kicklighter, D.W.; Bhatti, J.; Chapin, F. S.; De Groot, B.; Efremov, D.; Eugster, W.; Fukuda, M.; Gower, T.; Hinzman, L.; Huntley, B.; Jia, G.J.; Kasischke, E.; Melillo, J.; Romanovsky, V.; Shvidenko, A.; Vaganov, E.; Walker, D.

    2002-01-01

    The responses of high latitude ecosystems to global change involve complex interactions among environmental variables, vegetation distribution, carbon dynamics, and water and energy exchange. These responses may have important consequences for the earth system. In this study, we evaluated how vegetation distribution, carbon stocks and turnover, and water and energy exchange are related to environmental variation spanned by the network of the IGBP high latitude transects. While the most notable feature of the high latitude transects is that they generally span temperature gradients from southern to northern latitudes, there are substantial differences in temperature among the transects. Also, along each transect temperature co-varies with precipitation and photosynthetically active radiation, which are also variable among the transects. Both climate and disturbance interact to influence latitudinal patterns of vegetation and soil carbon storage among the transects, and vegetation distribution appears to interact with climate to determine exchanges of heat and moisture in high latitudes. Despite limitations imposed by the data we assembled, the analyses in this study have taken an important step toward clarifying the complexity of interactions among environmental variables, vegetation distribution, carbon stocks and turnover, and water and energy exchange in high latitude regions. This study reveals the need to conduct coordinated global change studies in high latitudes to further elucidate how interactions among climate, disturbance, and vegetation distribution influence carbon dynamics and water and energy exchange in high latitudes.

  3. 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. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. 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.

  5. High-Throughput Screening of the Asymmetric Decarboxylative Alkylation Reaction of Enolate-Stabilized Enol Carbonates

    KAUST Repository

    Stoltz, Brian; McDougal, Nolan; Virgil, Scott

    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.

  6. Amorphous carbon nanofibres inducing high specific capacitance of deposited hydrous ruthenium oxide

    International Nuclear Information System (INIS)

    Barranco, V.; Pico, F.; Ibanez, J.; Lillo-Rodenas, M.A.; Linares-Solano, A.; Kimura, M.; Oya, A.; Rojas, R.M.; Amarilla, J.M.; Rojo, J.M.

    2009-01-01

    Composites consisting of ruthenium oxide particles deposited on amorphous carbon nanofibres are prepared by a repetitive impregnation procedure. The choice of amorphous carbon nanofibres as support of amorphous ruthenium oxide leads to composites in which the deposited oxide consists of aggregates of extremely small primary particles (1-1.5 nm-size) and showing high porosity (specific surface area of 450 m 2 g -1 ). This special deposition of the oxide seems to favour: (i) high oxide capacitance (1000 Fg -1 ) at high oxide loadings (up to 20 wt%) and (ii) high capacitance retention (ca. 80% from the initial oxide capacitance) at high current densities (200 mA cm -2 ). Amorphous carbon nanofibres are suitable supports for amorphous ruthenium oxide and perhaps for other amorphous oxides acting as active electrode materials.

  7. Towards ultrahigh volumetric capacitance: graphene derived highly dense but porous carbons for supercapacitors

    Science.gov (United States)

    Tao, Ying; Xie, Xiaoying; Lv, Wei; Tang, Dai-Ming; Kong, Debin; Huang, Zhenghong; Nishihara, Hirotomo; Ishii, Takafumi; Li, Baohua; Golberg, Dmitri; Kang, Feiyu; Kyotani, Takashi; Yang, Quan-Hong

    2013-10-01

    A small volumetric capacitance resulting from a low packing density is one of the major limitations for novel nanocarbons finding real applications in commercial electrochemical energy storage devices. Here we report a carbon with a density of 1.58 g cm-3, 70% of the density of graphite, constructed of compactly interlinked graphene nanosheets, which is produced by an evaporation-induced drying of a graphene hydrogel. Such a carbon balances two seemingly incompatible characteristics: a porous microstructure and a high density, and therefore has a volumetric capacitance for electrochemical capacitors (ECs) up to 376 F cm-3, which is the highest value so far reported for carbon materials in an aqueous electrolyte. More promising, the carbon is conductive and moldable, and thus could be used directly as a well-shaped electrode sheet for the assembly of a supercapacitor device free of any additives, resulting in device-level high energy density ECs.

  8. 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.

  9. A graphene oxide-carbon nanotube grid for high-resolution transmission electron microscopy of nanomaterials

    International Nuclear Information System (INIS)

    Zhang Lina; Zhang Haoxu; Zhou Ruifeng; Chen Zhuo; Li Qunqing; Fan Shoushan; Jiang Kaili; Ge Guanglu; Liu Renxiao

    2011-01-01

    A novel grid for use in transmission electron microscopy is developed. The supporting film of the grid is composed of thin graphene oxide films overlying a super-aligned carbon nanotube network. The composite film combines the advantages of graphene oxide and carbon nanotube networks and has the following properties: it is ultra-thin, it has a large flat and smooth effective supporting area with a homogeneous amorphous appearance, high stability, and good conductivity. The graphene oxide-carbon nanotube grid has a distinct advantage when characterizing the fine structure of a mass of nanomaterials over conventional amorphous carbon grids. Clear high-resolution transmission electron microscopy images of various nanomaterials are obtained easily using the new grids.

  10. Crystalline and amorphous carbon nitride films produced by high-energy shock plasma deposition

    International Nuclear Information System (INIS)

    Bursilll, L.A.; Peng, Julin; Gurarie, V.N.; Orlov, A.V.; Prawer, S.

    1995-01-01

    High-energy shock plasma deposition techniques are used to produce carbon-nitride films containing both crystalline and amorphous components. The structures are examined by high-resolution transmission electron microscopy, parallel-electron-energy loss spectroscopy and electron diffraction. The crystalline phase appears to be face-centered cubic with unit cell parameter approx. a=0.63nm and it may be stabilized by calcium and oxygen at about 1-2 at % levels. The carbon atoms appear to have both trigonal and tetrahedral bonding for the crystalline phase. There is PEELS evidence that a significant fraction of the nitrogen atoms have sp 2 trigonal bonds in the crystalline phase. The amorphous carbon-nitride film component varies from essentially graphite, containing virtually no nitrogen, to amorphous carbon-nitride containing up to 10 at % N, where the fraction of sp 3 bonds is significant. 15 refs., 5 figs

  11. 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.

  12. Preparation of carbon quantum dots based high photostability luminescent membranes.

    Science.gov (United States)

    Zhao, Jinxing; Liu, Cui; Li, Yunchuan; Liang, Jiyuan; Liu, Jiyan; Qian, Tonghui; Ding, Jianjun; Cao, Yuan-Cheng

    2017-06-01

    Urethane acrylate (UA) was used to prepare carbon quantum dots (C-dots) luminescent membranes and the resultants were examined with FT-IR, mechanical strength, scanning electron microscope (SEM) and quantum yields (QYs). FT-IR results showed the polyurethane acrylate (PUA) prepolymer -C = C-vibration at 1101 cm -1 disappeared but there was strong vibration at1687cm -1 which was contributed from the-C = O groups in cross-linking PUA. Mechanical strength results showed that the different quantity of C-dots loadings and UV-curing time affect the strength. SEM observations on the cross-sections of the membranes are uniform and have no structural defects, which prove that the C-dots are compatible with the water-soluble PUA resin. The C-dot loading was increased from 0 to 1 g, the maximum tensile stress was nearly 2.67 MPa, but the tensile strain was decreased from 23.4% to 15.1% and 7.2% respectively. QYs results showed that the C-dots in the membrane were stable after 120 h continuous irradiation. Therefore, the C-dots photoluminescent film is the promising material for the flexible devices in the future applications. Copyright © 2016 John Wiley & Sons, Ltd.

  13. 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.

  14. Crystal size control of sulfathiazole using high pressure carbon dioxide

    Science.gov (United States)

    Kitamura, M.; Yamamoto, M.; Yoshinaga, Y.; Masuoka, H.

    1997-07-01

    The effect of the pressurization method of carbon dioxide on the crystallization behavior and crystal size of sulphathiazole (SUT) was investigated. In the "stepwise pressurization" method exceptionally large pillar-like crystals of 2-6 mm were obtained as mainly a scaling on the wall of the crystallizer. In the "rapid pressurization" method, crystals with a size one third to half of that obtained in the stepwise method precipitated, indicating the accelerated nucleation rate by the rapid increase of the supersaturation degree with a vigorous bubbling. With the new method of "two-step pressurization", in the first step the nucleation is accelerated with a much larger pressure instantly created, and in the second step the growth rate is retarded with the lower pressure. By this method much more fine crystals (from a few tens to several hundred micrometers) were produced and the scaling was suppressed. In this method a large supersaturation degree at an interface between the gas (bubble) and liquid phase under a vigorous bubbling may play an important role in accelerating the nucleation. The average size of the crystals tended to become smaller with increase of the first pressure and the expansion ratio at a decompression point, and it tended to get larger with increase of the second pressure. These results show that the GAS method is very useful for the control of crystal size over a wide range.

  15. Platinum decorated carbon nanotubes for highly sensitive amperometric glucose sensing

    International Nuclear Information System (INIS)

    Xie Jining; Wang Shouyan; Aryasomayajula, L; Varadan, V K

    2007-01-01

    Fine platinum nanoparticles (1-5 nm in diameter) were deposited on functionalized multi-walled carbon nanotubes (MWNTs) through a decoration technique. A novel type of enzymatic Pt/MWNTs paste-based mediated glucose sensor was fabricated. Electrochemical measurements revealed a significantly improved sensitivity (around 52.7 μA mM -1 cm -2 ) for glucose sensing without using any picoampere booster or Faraday cage. In addition, the calibration curve exhibited a good linearity in the range of 1-28 mM of glucose concentration. Transmission electron microscopy (TEM) and x-ray photoelectron spectroscopy (XPS) were performed to investigate the nanoscale structure and the chemical bonding information of the Pt/MWNTs paste-based sensing material, respectively. The improved sensitivity of this novel glucose sensor could be ascribed to its higher electroactive surface area, enhanced electron transfer, efficient enzyme immobilization, unique interaction in nanoscale and a synergistic effect on the current signal from possible multi-redox reactions

  16. 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.

  17. High Efficiency Flexible Battery Based on Graphene-carbon Nanotube Hybrid Structure

    Science.gov (United States)

    2015-02-26

    Choi, Carbon 77 1065(2014) 2. Hierarchical NiCo2O4@nickel-sulfide nanoplate arrays for high-performance supercapacitors , Chu Q, Wang W, Wang X...Graphene:Synthesis and Applications, CRC Press ISBN-10: 1439861870 | ISBN-13: 978-1439861875 | Publication Date: October 11, 2011 Handbook of Nanomaterials ...Properties, Carbon Nanomaterials : a review, Nitin Choudhary, Sookhyun Hwang, Wonbong Choi, Springer (2013) 15. Santanu Das and Wonbong Choi, Graphene

  18. High yield growth of patterned vertically aligned carbon nanotubes using inkjet-printed catalyst.

    Science.gov (United States)

    Beard, James D; Stringer, Jonathan; Ghita, Oana R; Smith, Patrick J

    2013-10-09

    This study reports on the fabrication of vertically aligned carbon nanotubes localized at specific sites on a growth substrate by deposition of a nanoparticle suspension using inkjet printing. Carbon nanotubes were grown with high yield as vertically aligned forests to a length of approximately 400 μm. The use of inkjet printing for catalyst fabrication considerably improves the production rate of vertically aligned patterned nanotube forests compared with conventional patterning techniques, for example, electron beam lithography or photolithography.

  19. Study of LiFePO{sub 4} cathode materials coated with high surface area carbon

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Cheng-Zhang; Fey, George Ting-Kuo [Department of Chemical and Materials Engineering, National Central University, Chung-Li 32054 (China); Kao, Hsien-Ming [Department of Chemistry, National Central University, Chung-Li 32054 (China)

    2009-04-01

    LiFePO{sub 4} is a potential cathode material for 4 V lithium-ion batteries. Carbon-coated lithium iron phosphates were prepared using a high surface area carbon to react precursors through a solid-state process, during which LiFePO{sub 4} particles were embedded in amorphous carbon. The carbonaceous materials were synthesized by the pyrolysis of peanut shells under argon, where they were carbonized in a two-step process that occurred between 573 and 873 K. The shells were also treated with a proprietary porogenic agent with the goal of altering the pore structure and surface area of the pyrolysis products. The electrochemical properties of the as-prepared LiFePO{sub 4}/C composite cathode materials were systematically characterized by X-ray diffraction, scanning electron microscope, element mapping, energy dispersive spectroscopy, Raman spectroscopy, and total organic carbon (TOC) analysis. In LiFePO{sub 4}/C composites, the carbon not only increases rate capability, but also stabilizes capacity. In fact, the capacity of the composites increased with the specific surface area of carbon. The best result was observed with a composite made of 8.0 wt.% with a specific surface area of 2099 m{sup 2} g{sup -1}. When high surface area carbon was used as a carbon source to produce LiFePO{sub 4}, overall conductivity increased from 10{sup -8} to 10{sup -4} S cm{sup -1}, because the inhibition of particle growth during the final sintering process led to greater specific capacity, improved cycling properties and better rate capability compared to a pure olivine LiFePO{sub 4} material. (author)

  20. Development of highly microporous activated carbon from the alcoholic beverage industry organic by-products

    International Nuclear Information System (INIS)

    Nieto-Delgado, C.; Terrones, M.; Rangel-Mendez, J.R.

    2011-01-01

    This work has the aim to employ the agave bagasse, a waste from Tequila and Mescal industries, to obtain a product of high commercial value such as activated carbon. The activated carbon production methodology was based on a chemical activation, by using ZnCl 2 and H 3 PO 4 as activating agent and agave bagasse as a natural source of carbon. The activation temperature (150-450 o C), activation time (0-60 min) and weight ratio of activating agent to precursor (0.2-4) were studied. The produced carbon materials were characterized by scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and nitrogen physisorption at -196 o C. In addition, the activating agent recovery was evaluated. We were able to obtain highly microporous activated carbons with micropore volumes between 0.24 and 1.20 cm 3 /g and a surface area within 300 and 2139 m 2 /g. These results demonstrated the feasibility to treat the industrial wastes of the Tequila and Mescal industries, being this wastes an excellent precursor to produce highly microporous activated carbons that can be processed at low activation temperatures in short times, with the possibility of recycling the activating agent.

  1. 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.

  2. Carbon Textile Decorated with Pseudocapacitive VC/Vx Oy for High-Performance Flexible Supercapacitors.

    Science.gov (United States)

    Van Lam, Do; Shim, Hyung Cheoul; Kim, Jae-Hyun; Lee, Hak-Joo; Lee, Seung-Mo

    2017-11-01

    It is demonstrated that, via V 2 O 5 coating by low temperature atomic layer deposition and subsequent pyrolysis, ubiquitous cotton textile can readily turn into high-surface-area carbon textile fully decorated with pseudocapacitive V x O y /VC widely usable as electrodes of high-performance supercapacitor. It is found that carbothermic reduction of V 2 O 5 (C + V 2 O 5 → C' + VC + CO/CO 2 (g)) leads to chemical/mechanical activation of carbon textile, thereby producing high-surface-area conductive carbon textile. In addition, sequential phase transformation and carbide formation (V 2 O 5 → V x O y → VC) occurred by carbothermic reduction trigger decoration of the carbon textile with redox-active V x O y /VC. Thanks to the synergistic effect of electrical double layer and pseudocapacitance, the supercapacitors made of the hybrid carbon textile exhibit far better energy density (over 30-fold increase) with excellent cycling stability than the carbon textile simply undergone pyrolysis. The method can open up a promising and facile way to synthesize hybrid electrode materials for electrochemical energy storages possessing advantages of both electrical double layer and pseudocapacitive material. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Three-dimensional interconnected porous graphitic carbon derived from rice straw for high performance supercapacitors

    Science.gov (United States)

    Jin, Hong; Hu, Jingpeng; Wu, Shichao; Wang, Xiaolan; Zhang, Hui; Xu, Hui; Lian, Kun

    2018-04-01

    Three-dimensional interconnected porous graphitic carbon materials are synthesized via a combination of graphitization and activation process with rice straw as the carbon source. The physicochemical properties of the three-dimensional interconnected porous graphitic carbon materials are characterized by Nitrogen adsorption/desorption, Fourier-transform infrared spectroscopy, X-ray diffraction, Raman spectroscopy, Scanning electron microscopy and Transmission electron microscopy. The results demonstrate that the as-prepared carbon is a high surface area carbon material (a specific surface area of 3333 m2 g-1 with abundant mesoporous and microporous structures). And it exhibits superb performance in symmetric double layer capacitors with a high specific capacitance of 400 F g-1 at a current density of 0.1 A g-1, good rate performance with 312 F g-1 under a current density of 5 A g-1 and favorable cycle stability with 6.4% loss after 10000 cycles at a current density of 5 A g-1 in the aqueous electrolyte of 6M KOH. Thus, rice straw is a promising carbon source for fabricating inexpensive, sustainable and high performance supercapacitors' electrode materials.

  4. Arterial stiffness

    Directory of Open Access Journals (Sweden)

    Ursula Quinn

    2012-09-01

    Full Text Available Measurements of biomechanical properties of arteries have become an important surrogate outcome used in epidemiological and interventional cardiovascular research. Structural and functional differences of vessels in the arterial tree result in a dampening of pulsatility and smoothing of blood flow as it progresses to capillary level. A loss of arterial elastic properties results a range of linked pathophysiological changes within the circulation including increased pulse pressure, left ventricular hypertrophy, subendocardial ischaemia, vessel endothelial dysfunction and cardiac fibrosis. With increased arterial stiffness, the microvasculature of brain and kidneys are exposed to wider pressure fluctuations and may lead to increased risk of stroke and renal failure. Stiffening of the aorta, as measured by the gold-standard technique of aortic Pulse Wave Velocity (aPWV, is independently associated with adverse cardiovascular outcomes across many different patient groups and in the general population. Therefore, use of aPWV has been proposed for early detection of vascular damage and individual cardiovascular risk evaluation and it seems certain that measurement of arterial stiffness will become increasingly important in future clinical care. In this review we will consider some of the pathophysiological processes that result from arterial stiffening, how it is measured and factors that may drive it as well as potential avenues for therapy. In the face of an ageing population where mortality from atheromatous cardiovascular disease is falling, pathology associated with arterial stiffening will assume ever greater importance. Therefore, understanding these concepts for all clinicians involved in care of patients with cardiovascular disease will become vital.

  5. High-Level Heteroatom Doped Two-Dimensional Carbon Architectures for Highly Efficient Lithium-Ion Storage

    Directory of Open Access Journals (Sweden)

    Zhijie Wang

    2018-04-01

    Full Text Available In this work, high-level heteroatom doped two-dimensional hierarchical carbon architectures (H-2D-HCA are developed for highly efficient Li-ion storage applications. The achieved H-2D-HCA possesses a hierarchical 2D morphology consisting of tiny carbon nanosheets vertically grown on carbon nanoplates and containing a hierarchical porosity with multiscale pore size. More importantly, the H-2D-HCA shows abundant heteroatom functionality, with sulfur (S doping of 0.9% and nitrogen (N doping of as high as 15.5%, in which the electrochemically active N accounts for 84% of total N heteroatoms. In addition, the H-2D-HCA also has an expanded interlayer distance of 0.368 nm. When used as lithium-ion battery anodes, it shows excellent Li-ion storage performance. Even at a high current density of 5 A g−1, it still delivers a high discharge capacity of 329 mA h g−1 after 1,000 cycles. First principle calculations verifies that such unique microstructure characteristics and high-level heteroatom doping nature can enhance Li adsorption stability, electronic conductivity and Li diffusion mobility of carbon nanomaterials. Therefore, the H-2D-HCA could be promising candidates for next-generation LIB anodes.

  6. Nacre-Templated Synthesis of Highly Dispersible Carbon Nanomeshes for Layered Membranes with High-Flux Filtration and Sensing Properties.

    Science.gov (United States)

    Kong, Meng; Li, Mingjie; Shang, Ruoxu; Wu, Jingyu; Yan, Peisong; Xu, Dongmei; Li, Chaoxu

    2018-01-24

    Marine shells not only represent a rapidly accumulating type of fishery wastes but also offer a unique sort of hybrid nanomaterials produced greenly and massively in nature. The elaborate "brick and mortar" structures of nacre enabled the synthesis of carbon nanomeshes with <1 nm thickness, hierarchical porosity, and high specific surface area through pyrolysis, in which two-dimensional (2D) organic layers served as the carbonaceous precursor and aragonite platelets as the hard template. Mineral bridges within 2D organic layers templated the formation of mesh pores of 20-70 nm. In contrast to other hydrophobic carbon nanomaterials, these carbon nanomeshes showed super dispersibility in diverse solvents and thus processability for membranes through filtration, patterning, spray-coating, and ink-writing. The carbon membranes with layered structures were capable of serving not only for high-flux filtration and continuous flow absorption but also for electrochemical and strain sensing with high sensitivity. Thus, utilization of marine shells, on one hand, relieves the environmental concern of shellfish waste, on the other hand, offers a facile, green, low-cost, and massive approach to synthesize unique carbon nanomeshes alternative to graphene nanomeshes and applicable in environmental adsorption, filtration, wearable sensors, and flexible microelectronics.

  7. A further study of the high incidence of the median artery of the forearm in Southern Africa.

    Science.gov (United States)

    Henneberg, M; George, B J

    1992-01-01

    Sixty-two forearms from 36 cadavers of South Africans of European extraction were dissected. The frequency of the median artery per forearm was 27.4%. There was neither bilateral difference nor sexual dimorphism in the incidence of the artery. These findings compare well with a previous study of black South Africans (Henneberg & George, 1992) where frequency per forearm was 27.1%. Our findings are much higher than those of earlier studies. This discrepancy may be explained either by differences in the thoroughness of the observations or regional variation, or by the occurrence of a secular trend in the development of vasculature. Images Fig. 1 Fig. 2 PMID:1294564

  8. Midterm Results after Uterine Artery Embolization Versus MR-Guided High-Intensity Focused Ultrasound Treatment for Symptomatic Uterine Fibroids

    Energy Technology Data Exchange (ETDEWEB)

    Froeling, V., E-mail: vera.froeling@charite.de; Meckelburg, K., E-mail: katrin.meckelburg@charite.de; Scheurig-Muenkler, C., E-mail: christian.scheurig-muenkler@charite.de; Schreiter, N. F., E-mail: nils.schreiter@charite.de; Kamp, J., E-mail: julia.kamp@charite.de; Maurer, M. H., E-mail: martin.maurer@charite.de; Beck, A., E-mail: alexander.beck@charite.de; Hamm, B., E-mail: bernd.hamm@charite.de; Kroencke, T. J., E-mail: Thomas.kroencke@charite.de [Charite-Universitaetsmedizin Berlin, Department of Radiology (Germany)

    2013-12-15

    Purpose: To compare the rate of reintervention and midterm changes in symptom severity (SS) and Total health-related quality of life (HRQoL) scores after uterine artery embolization (UAE) and magnetic resonance-guided high-intensity focused ultrasound (MR-g HIFU) for symptomatic uterine fibroids. Methods: Eighty women (median age 38.3 years), equally eligible for MR-g HIFU and UAE who underwent one of both treatments between 2002 and 2009 at our institution, were included. The primary end point of the study was defined as the rate of reintervention after both therapies. The secondary outcome was defined as changes in SS and Total HRQoL scores after treatment. SS and Total HRQoL scores before treatment and at midterm follow-up (median 13.3 months) were assessed by the uterine fibroid symptom and quality-of-life questionnaire (UFS-QoL) and compared. Results: The rate of reintervention was significantly lower after UAE than after MR-g HIFU (p = 0.002). After both treatments, SS and Total HRQoL scores improved significantly from baseline to follow-up (UAE: p < 0.001, p < 0.001; MR-g HIFU: p = 0.002, p < 0.001). Total HRQoL scores were significantly higher after UAE than after MR-g HIFU (p = 0.032). Changes in the SS scores did not differ significantly for both treatments (p = 0.061). Conclusion: UAE and MR-g HIFU significantly improved the health-related quality of life of women with symptomatic uterine fibroids. After UAE, the change in Total HRQoL score improvement was significantly better, and a significantly lower rate of reintervention was observed.

  9. Midterm Results after Uterine Artery Embolization Versus MR-Guided High-Intensity Focused Ultrasound Treatment for Symptomatic Uterine Fibroids

    International Nuclear Information System (INIS)

    Froeling, V.; Meckelburg, K.; Scheurig-Muenkler, C.; Schreiter, N. F.; Kamp, J.; Maurer, M. H.; Beck, A.; Hamm, B.; Kroencke, T. J.

    2013-01-01

    Purpose: To compare the rate of reintervention and midterm changes in symptom severity (SS) and Total health-related quality of life (HRQoL) scores after uterine artery embolization (UAE) and magnetic resonance–guided high-intensity focused ultrasound (MR-g HIFU) for symptomatic uterine fibroids. Methods: Eighty women (median age 38.3 years), equally eligible for MR-g HIFU and UAE who underwent one of both treatments between 2002 and 2009 at our institution, were included. The primary end point of the study was defined as the rate of reintervention after both therapies. The secondary outcome was defined as changes in SS and Total HRQoL scores after treatment. SS and Total HRQoL scores before treatment and at midterm follow-up (median 13.3 months) were assessed by the uterine fibroid symptom and quality-of-life questionnaire (UFS-QoL) and compared. Results: The rate of reintervention was significantly lower after UAE than after MR-g HIFU (p = 0.002). After both treatments, SS and Total HRQoL scores improved significantly from baseline to follow-up (UAE: p < 0.001, p < 0.001; MR-g HIFU: p = 0.002, p < 0.001). Total HRQoL scores were significantly higher after UAE than after MR-g HIFU (p = 0.032). Changes in the SS scores did not differ significantly for both treatments (p = 0.061). Conclusion: UAE and MR-g HIFU significantly improved the health-related quality of life of women with symptomatic uterine fibroids. After UAE, the change in Total HRQoL score improvement was significantly better, and a significantly lower rate of reintervention was observed

  10. Duration of high-dose aspirin therapy does not affect long-term coronary artery outcomes in Kawasaki disease.

    Science.gov (United States)

    Migally, Karl; Braunlin, Elizabeth A; Zhang, Lei; Binstadt, Bryce A

    2018-05-02

    BackgroundHigh-dose aspirin (HDA) is used with intravenous immunoglobulin (IVIg) in Kawasaki disease (KD). Practice regarding HDA varies, and it is unclear whether HDA duration affects the long-term course.MethodsWe retrospectively studied KD patients at our hospital for over 10 years. Patients were categorized as having received HDA for 0, 1-7, or >7 days. Primary outcome was the maximum coronary Z-score at diagnosis and follow-up; secondary outcomes included inflammatory markers.ResultsOne hundred and three patients had HDA duration documented, of which 35 patients had coronary artery abnormalities (CAAs) at diagnosis. There was no difference in demographics or inflammatory markers between the HDA groups, and no difference in HDA duration between patients with or without CAAs. Seventeen patients received no HDA; they had longer illness and defervescence duration before diagnosis, and were less likely to receive IVIg. For CAAs, multivariate regression revealed that HDA duration did not predict the coronary Z-score at 9-15 months. Higher Z-score at diagnosis was associated with higher Z-score at 9-15 months.ConclusionThe only factor associated with coronary Z-score at 9-15 months was the Z-score at diagnosis. At our institution, longer illness and defervescence duration and the lack of IVIg administration were associated with not administering HDA. HDA duration did not affect the clinically relevant outcomes, particularly CAA persistence.Pediatric Research advance online publication, 2 May 2018; doi:10.1038/pr.2018.44.

  11. Role of high-resolution image integration to visualize left phrenic nerve and coronary arteries during epicardial ventricular tachycardia ablation.

    Science.gov (United States)

    Yamashita, Seigo; Sacher, Frédéric; Mahida, Saagar; Berte, Benjamin; Lim, Han S; Komatsu, Yuki; Amraoui, Sana; Denis, Arnaud; Derval, Nicolas; Laurent, François; Montaudon, Michel; Hocini, Mélèze; Haïssaguerre, Michel; Jaïs, Pierre; Cochet, Hubert

    2015-04-01

    Epicardial ventricular tachycardia (VT) ablation is associated with risks of coronary artery (CA) and phrenic nerve (PN) injury. We investigated the role of multidetector computed tomography in visualizing CA and PN during VT ablation. Ninety-five consecutive patients (86 men; age, 57 ± 15) with VT underwent cardiac multidetector computed tomography. The PN detection rate and anatomic variability were analyzed. In 49 patients undergoing epicardial mapping, real-time multidetector computed tomographic integration was used to display CAs/PN locations in 3-dimensional mapping systems. Elimination of local abnormal ventricular activities (LAVAs) was used as ablation end point. The distribution of CAs/PN with respect to LAVA was analyzed and compared between VT etiologies. Multidetector computed tomography detected PN in 81 patients (85%). Epicardial LAVAs were observed in 44 of 49 patients (15 ischemic cardiomyopathy, 15 nonischemic cardiomyopathy, and 14 arrhythmogenic right ventricular cardiomyopathy) with a mean of 35 ± 37 LAVA points/patient. LAVAs were located within 1 cm from CAs and PN in 35 (80%) and 18 (37%) patients, respectively. The prevalence of LAVA adjacent to CAs was higher in nonischemic cardiomyopathy and arrhythmogenic right ventricular cardiomyopathy than in ischemic cardiomyopathy (100% versus 86% versus 53%; P < 0.01). The prevalence of LAVAs adjacent to PN was higher in nonischemic cardiomyopathy than in ischemic cardiomyopathy (93% versus 27%; P < 0.001). Epicardial ablation was performed in 37 patients (76%). Epicardial LAVAs could not be eliminated because of the proximity to CAs or PN in 8 patients (18%). The epicardial electrophysiological VT substrate is often close to CAs and PN in patients with nonischemic cardiomyopathy. High-resolution image integration is potentially useful to minimize risks of PN and CA injury during epicardial VT ablation. © 2015 American Heart Association, Inc.

  12. Carbon Condensation during High Explosive Detonation with Time Resolved Small Angle X-ray Scattering

    Science.gov (United States)

    Hammons, Joshua; Bagge-Hansen, Michael; Nielsen, Michael; Lauderbach, Lisa; Hodgin, Ralph; Bastea, Sorin; Fried, Larry; May, Chadd; Sinclair, Nicholas; Jensen, Brian; Gustavsen, Rick; Dattelbaum, Dana; Watkins, Erik; Firestone, Millicent; Ilavsky, Jan; van Buuren, Tony; Willey, Trevor; Lawrence Livermore National Lab Collaboration; Los Alamos National Laboratory Collaboration; Washington State University/Advanced Photon Source Team

    Carbon condensation during high-energy detonations occurs under extreme conditions and on very short time scales. Understanding and manipulating soot formation, particularly detonation nanodiamond, has attracted the attention of military, academic and industrial research. An in-situ characterization of these nanoscale phases, during detonation, is highly sought after and presents a formidable challenge even with today's instruments. Using the high flux available with synchrotron X-rays, pink beam small angle X-ray scattering is able to observe the carbon phases during detonation. This experimental approach, though powerful, requires careful consideration and support from other techniques, such as post-mortem TEM, EELS and USAXS. We present a comparative survey of carbon condensation from different CHNO high explosives. This work was performed under the auspices of the US DOE by LLNL under Contract DE-AC52-07NA27344.

  13. High-flavanol and high-theobromine versus low-flavanol and low-theobromine chocolate to improve uterine artery pulsatility index: a double blind randomized clinical trial.

    Science.gov (United States)

    Bujold, Emmanuel; Leblanc, Vicky; Lavoie-Lebel, Élise; Babar, Asma; Girard, Mario; Poungui, Lionel; Blanchet, Claudine; Marc, Isabelle; Lemieux, Simone; Belkacem, Abdous; Sidi, Elhadji Laouan; Dodin, Sylvie

    2017-09-01

    To evaluate the impact of high-flavanol and high-theobromine (HFHT) chocolate in women at risk of preeclampsia (PE). We conducted a single-center randomized controlled trial including women with singleton pregnancy between 11 and 14 weeks gestation who had bilateral abnormal uterine artery (UtA) waveforms (notching) and elevated pulsatility index (PI). Participants were randomized to either HFHT or low-flavanol and low-theobromine (LFLT) chocolate (30 grams daily for a total of 12 weeks). UtA PI, reported as multiple of medians (MoM) adjusted for gestational age, was assessed at baseline and 12 weeks after randomization. One hundred thirty-one women were randomized with mean gestational age of 12.4 ± 0.6 weeks and a mean UtA PI of 1.39 ± 0.31 MoM. UtA PI adjusted for gestational age significantly decreased from baseline to the second visit (12 weeks later) in the two groups (p chocolate, daily intake of HFHT chocolate was not associated with significant changes of UtA PI. Nevertheless, the improvement observed in both groups suggests that chocolate could improve placental function independently of flavanol and/or theobromine content.

  14. High-resolution transmission electron microscopy and energetics of flattened carbon nonoshells

    International Nuclear Information System (INIS)

    Bourgeois, L.N.; Bursill, L.A.

    1998-01-01

    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)

  15. Highly sensitive voltamperometric determination of pyritinol using carbon nanofiber/gold nanoparticle composite screen-printed carbon electrode

    Directory of Open Access Journals (Sweden)

    Apetrei IM

    2017-07-01

    Full Text Available Irina Mirela Apetrei,1 Constantin Apetrei2 1Department of Pharmaceutical Sciences, Medical and Pharmaceutical Research Center, Faculty of Medicine and Pharmacy, 2Department of Chemistry, Physics and Environment, Faculty of Sciences and Environment, “Dunarea de Jos” University of Galati, Galati, Romania Abstract: A novel and highly sensitive electrochemical method for the detection of pyritinol in pharmaceutical products and serum samples has been accomplished based on voltamperometric response of pyritinol in carbon nanofiber-gold nanoparticle (CNF-GNP-modified screen-printed carbon electrode (SPCE. The electrochemical response of pyritinol to CNF-GNP-modified SPCE was studied by cyclic voltammetry and square-wave voltammetry (SWV. Under optimized working conditions, the novel sensor shows excellent voltamperometric response toward pyritinol. The SWV study shows significantly enhanced electrochemical response for pyritinol in CNF-GNP-modified SPCE providing high sensitivity to the novel sensor for pyritinol detection. The peak current for pyritinol is found to be linear with the concentration in the range 1.0×10-8–5.0×10-5 M with a detection limit of 6.23×10-9 M using SWV as the detection method. The viability of the new developed sensor for the analytical purposes was studied by performing experiments on various commercial pharmaceutical products and blood serum samples, which yielded adequate recoveries of pyritinol. The novel electrochemical sensor provides high sensitivity, enhanced selectivity, good reproducibility and practical applicability. Keywords: pyritinol, carbon nanofiber, gold nanoparticle, sensor, square-wave voltammetry

  16. Three-Dimensional Water and Carbon Cycle Modeling at High Spatial-Temporal Resolutions

    Science.gov (United States)

    Liao, C.; Zhuang, Q.

    2017-12-01

    Terrestrial ecosystems in cryosphere are very sensitive to the global climate change due to the presence of snow covers, mountain glaciers and permafrost, especially when the increase in near surface air temperature is almost twice as large as the global average. However, few studies have investigated the water and carbon cycle dynamics using process-based hydrological and biogeochemistry modeling approach. In this study, we used three-dimensional modeling approach at high spatial-temporal resolutions to investigate the water and carbon cycle dynamics for the Tanana Flats Basin in interior Alaska with emphases on dissolved organic carbon (DOC) dynamics. The results have shown that: (1) lateral flow plays an important role in water and carbon cycle, especially in dissolved organic carbon (DOC) dynamics. (2) approximately 2.0 × 104 kg C yr-1 DOC is exported to the hydrological networks and it compromises 1% and 0.01% of total annual gross primary production (GPP) and total organic carbon stored in soil, respectively. This study has established an operational and flexible framework to investigate and predict the water and carbon cycle dynamics under the changing climate.

  17. High efficient and continuous surface modification of carbon fibers with improved tensile strength and interfacial adhesion

    Science.gov (United States)

    Sun, Jingfeng; Zhao, Feng; Yao, Yue; Jin, Zhen; Liu, Xu; Huang, Yudong

    2017-08-01

    Most of the surface modification technologies for carbon fibers, no matter in laboratory scale or for commercial manufacture, are accompanied by a simultaneous decrease in tensile strength. In this paper, a feasible and high efficient strategy for carbon fiber treatment which could obviously improve both tensile strength and interfacial adhesion was proposed. Continuously moving carbon fibers were treated with atmospheric helium plasma for 1 min, followed by a 5 min pyrolytic carbon deposition using ethanol as precursor at 800 °C. The effects of the new approach were characterized by SEM, AFM, nanoindentation, XPS, Raman, wettability analysis, single fiber tensile strength testing and single fiber pull-out testing. After modification, pyrolytic carbon coating was deposited on the fiber surface uniformly, and the roughness and surface energy increased significantly. The single fiber tensile testing results indicate that the resulting fiber strength increased 15.7%, rising from 3.13 to 3.62 GPa. Meanwhile, the interfacial shear strength of its epoxy composites increased from 65.3 to 83.5 MPa. The comparative studies of carbon fibers modified with commercial anodic oxidation and sizing were also carried out. The results demonstrate that the new method can be utilized in the carbon fiber manufacture process and is more efficient than the traditional approaches.

  18. 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.

  19. Carotid artery surgery

    Science.gov (United States)

    Carotid endarterectomy; CAS surgery; Carotid artery stenosis - surgery; Endarterectomy - carotid artery ... through the catheter around the blocked area during surgery. Your carotid artery is opened. The surgeon removes ...

  20. Hierarchical porous carbons prepared by an easy one-step carbonization and activation of phenol-formaldehyde resins with high performance for supercapacitors

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Zhoujun [State Key Laboratory of High Performance Ceramics and Superfine Microstructures, Graduate School, Shanghai Institute of Ceramics, Chinese Academy of Science, 1295 Dingxi Road, Shanghai 200050 (China); Gao, Qiuming [State Key Laboratory of High Performance Ceramics and Superfine Microstructures, Graduate School, Shanghai Institute of Ceramics, Chinese Academy of Science, 1295 Dingxi Road, Shanghai 200050 (China); School of Chemistry and Environment, Beihang University, 37 Xueyuan Road, Haidian District, Beijing 100191 (China)

    2011-02-01

    Hierarchical porous carbons are prepared by an easy one-step process of carbonization and activation derived from phenol-formaldehyde resins, in which potassium hydroxide acts as both the catalyst of polymerization and the activation reagent. The simple one-step preparation saves the cost of carbons and leads to high yield. The porous carbons have high surface areas with abundant pore structures. The plenty of micropores and small mesopores increase the capacitance and make the electrolyte ions diffuse fast into the pores. These hierarchical porous carbons show high performance for supercapacitors possessing of the optimized capacitance of 234 F g{sup -1} in aqueous electrolyte and 137 F g{sup -1} in organic electrolyte with high capacitive retention. (author)

  1. High Residual Collagen-Induced Platelet Reactivity Predicts Development of Restenosis in the Superficial Femoral Artery After Percutaneous Transluminal Angioplasty in Claudicant Patients

    Energy Technology Data Exchange (ETDEWEB)

    Gary, Thomas, E-mail: thomas.gary@medunigraz.at [Medical University of Graz, Division of Angiology, Department of Internal Medicine (Austria); Prüller, Florian, E-mail: florian.prueller@klinikum-graz.at; Raggam, Reinhard, E-mail: reinhard.raggam@klinikum-graz.at [Medical University of Graz, Clinical Institute of Medical and Chemical Laboratory Diagnostics (Austria); Mahla, Elisabeth, E-mail: elisabeth.mahla@medunigraz.at [Medical University of Graz, Department of Anesthesiology and Intensive Care Medicine (Austria); Eller, Philipp, E-mail: philipp.eller@medunigraz.at; Hafner, Franz, E-mail: franz.hafner@klinikum-graz.at; Brodmann, Marianne, E-mail: marianne.brodmann@medunigraz.at [Medical University of Graz, Division of Angiology, Department of Internal Medicine (Austria)

    2016-02-15

    PurposeAlthough platelet reactivity is routinely inhibited with aspirin after percutaneous angioplasty (PTA) in peripheral arteries, the restenosis rate in the superficial femoral artery (SFA) is high. Interaction of activated platelets and the endothelium in the region of intervention could be one reason for this as collagen in the subendothelium activates platelets.Materials and MethodsA prospective study evaluating on-site platelet reactivity during PTA and its influence on the development of restenosis with a total of 30 patients scheduled for PTA of the SFA. Arterial blood was taken from the PTA site after SFA; platelet function was evaluated with light transmission aggregometry. After 3, 6, 12, and 24 months, duplex sonography was performed and the restenosis rate evaluated.ResultsEight out of 30 patients developed a hemodynamically relevant restenosis (>50 % lumen narrowing) in the PTA region during the 24-month follow-up period. High residual collagen-induced platelet reactivity defined as AUC >30 was a significant predictor for the development of restenosis [adjusted odds ratio 11.8 (9.4, 14.2); P = .04].ConclusionsHigh residual collagen-induced platelet reactivity at the interventional site predicts development of restenosis after PTA of the SFA. Platelet function testing may be useful for identifying patients at risk.

  2. Arterial responses during migraine headache

    DEFF Research Database (Denmark)

    Iversen, Helle Klingenberg; Nielsen, T H; Olesen, J

    1990-01-01

    The superficial temporal artery has been thought to be the main focus of pain during migraine attacks, but its diameter has never been measured directly. The use of a new, high-resolution ultrasound machine to measure arterial size in 25 migraine patients with unilateral head pain showed...... that the lumen was wider on the painful than on the non-painful side during a migraine attack. The diameters of both radial arteries and the temporal artery on the non-painful side were smaller during than between attacks. The generalised vasoconstriction was not shared by the temporal artery on the affected...... side, which suggests a local vasodilatory response. The findings suggest that cephalic arteries may play a role in migraine pathogenesis....

  3. Measuring arterial oxygenation in a high altitude field environment: comparing portable pulse oximetry with blood gas analysis.

    Science.gov (United States)

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

    2013-06-01

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

  4. Highly sensitive and selective determination of methylergometrine maleate using carbon nanofibers/silver nanoparticles composite modified carbon paste electrode.

    Science.gov (United States)

    Kalambate, Pramod K; Rawool, Chaitali R; Karna, Shashi P; Srivastava, Ashwini K

    2016-12-01

    A highly sensitive and selective voltammetric method for determination of Methylergometrine maleate (MM) in pharmaceutical formulations, urine and blood serum samples has been developed based on enhanced electrochemical response of MM at carbon nanofibers and silver nanoparticles modified carbon paste electrode (CNF-AgNP-CPE). The electrode material was characterized by various techniques viz., X-ray diffraction, scanning electron microscopy and energy dispersive X-ray spectroscopy. The electrocatalytic response of MM at CNF-AgNP-CPE was studied by cyclic voltammetry (CV), differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy (EIS). Under optimized conditions, the proposed sensor exhibits excellent electrochemical response towards MM. The DPV study shows greatly enhanced electrochemical signal for MM at CNF-AgNP-CPE lending high sensitivity to the proposed sensor for MM detection. The peak (Ip) current for MM is found to be rectilinear in the range 4.0×10(-8)-2.0×10(-5)M with a detection limit of 7.1×10(-9)M using DPV. The feasibility of the proposed sensor in analytical applications was investigated by conducting experiments on commercial pharmaceutical formulations, human urine and blood serum samples, which yielded satisfactory recoveries of MM. The proposed electrochemical sensor offers high sensitivity, selectivity, reproducibility and practical utility. We recommend it as an authentic and productive electrochemical sensor for successful determination of MM. Copyright © 2016. Published by Elsevier B.V.

  5. Highly sensitive hydrogen peroxide sensor based on a glassy carbon electrode modified with platinum nanoparticles on carbon nanofiber heterostructures

    International Nuclear Information System (INIS)

    Yang, Yang; Fu, Renzhong; Yuan, Jianjun; Wu, Shiyuan; Zhang, Jialiang; Wang, Haiying

    2015-01-01

    We are presenting a sensor for hydrogen peroxide (H 2 O 2 ) that is based on the use of a heterostructure composed of Pt nanoparticles (NPs) and carbon nanofibers (CNFs). High-density Pt NPs were homogeneously loaded onto a three-dimensional nanostructured CNF matrix and then deposited in a glassy carbon electrode (GCE). The resulting sensor synergizes the advantages of the conducting CNFs and the nanoparticle catalyst. The porous structure of the CNFs also favor the high-density immobilization of the NPs and the diffusion of water-soluble molecules, and thus assists the rapid catalytic oxidation of H 2 O 2 . If operated at a working voltage of −0.2 V (vs. Ag/AgCl), the modified GCE exhibits a linear response to H 2 O 2 in the 5 μM to 15 mM concentration range (total analytical range: 5 μM to 100 mM), with a detection limit of 1.7 μM (at a signal-to-noise ratio of 3). The modified GCE is not interfered by species such as uric acid and glucose. Its good stability, high selectivity and good reproducibility make this electrode a valuable tool for inexpensive amperometric sensing of H 2 O 2 . (author)

  6. Divertor materials for ITER - Tungsten and carbon/carbon composite behavior under coupled ionic irradiation and high temperature

    Energy Technology Data Exchange (ETDEWEB)

    Raunier, S.; Balat-Pichelin, M.; Sans, J.L.; Hernandez, D. [Laboratoire PROMES-CNRS, Laboratoire Procedes, Materiaux et Energie Solaire, 7 rue du Four Solaire, 66120 Font-Romeu Odeillo (France)

    2007-07-01

    Full text of publication follows: In the frame of the International Thermonuclear Experimental Reactor ITER, the physical-chemical characterization of plasma-facing components (divertor and structural materials) is essential because they are subjected to simultaneous high thermal and ionic fluxes. In this paper, an experimental and theoretical study of the physical-chemical behavior of carbon/carbon composite and tungsten (materials for ITER divertor) under extreme conditions is performed. The simulation of the interaction of hydrogen ions with the material, the theoretical study of physical erosion (TRIM and TRIDYN codes) and the chemical erosion (GEMINI code) are carried out. The conditions of nominal or accidental mode that can occur during the operation of the reactor (high temperature 1300 - 2500 K, high vacuum, H{sup +} ionic flux with different energies) are experimentally simulated. In this work, we have studied the material degradation, the mass loss kinetics, the characterization of the emitted neutral and charged species of heated and both heated and irradiated materials, and the determination of the thermo-radiative properties versus time. This study, done in collaboration with CEA Cadarache, is realized using the MEDIASE experimental device (Moyen d'Essai et de Diagnostic en Ambiance Solaire Extreme) located at the focus of the 1000 kW solar furnace of PROMES-CNRS laboratory in Odeillo. Material characterization pre- and post-processing is performed with classical techniques as SEM, XRD and XPS and also by measuring the BRDF (Bidirectional Reflectivity Diffusion Function). (authors)

  7. Divertor materials for ITER - Tungsten and carbon/carbon composite behavior under coupled ionic irradiation and high temperature

    International Nuclear Information System (INIS)

    Raunier, S.; Balat-Pichelin, M.; Sans, J.L.; Hernandez, D.

    2007-01-01

    Full text of publication follows: In the frame of the International Thermonuclear Experimental Reactor ITER, the physical-chemical characterization of plasma-facing components (divertor and structural materials) is essential because they are subjected to simultaneous high thermal and ionic fluxes. In this paper, an experimental and theoretical study of the physical-chemical behavior of carbon/carbon composite and tungsten (materials for ITER divertor) under extreme conditions is performed. The simulation of the interaction of hydrogen ions with the material, the theoretical study of physical erosion (TRIM and TRIDYN codes) and the chemical erosion (GEMINI code) are carried out. The conditions of nominal or accidental mode that can occur during the operation of the reactor (high temperature 1300 - 2500 K, high vacuum, H + ionic flux with different energies) are experimentally simulated. In this work, we have studied the material degradation, the mass loss kinetics, the characterization of the emitted neutral and charged species of heated and both heated and irradiated materials, and the determination of the thermo-radiative properties versus time. This study, done in collaboration with CEA Cadarache, is realized using the MEDIASE experimental device (Moyen d'Essai et de Diagnostic en Ambiance Solaire Extreme) located at the focus of the 1000 kW solar furnace of PROMES-CNRS laboratory in Odeillo. Material characterization pre- and post-processing is performed with classical techniques as SEM, XRD and XPS and also by measuring the BRDF (Bidirectional Reflectivity Diffusion Function). (authors)

  8. Solubility of carbon dioxide in secondary butyl alcohol at high pressures : experimental and modeling with CPA

    NARCIS (Netherlands)

    Raeissi, S.; Haghbaksh, R.; Florusse, L.J.; Peters, C.J.

    2015-01-01

    Mixtures of carbon dioxide and secondary butyl alcohol at high pressures are interesting for a range of industrial applications. Therefore, it is important to have trustworthy experimental data on the high-pressure phase behavior of this mixture over a wide range of temperatures. In addition, an

  9. Extracranial Carotid Artery Stenting in Surgically High-Risk Patients Using the Carotid Wallstent Endoprosthesis:Midterm Clinical and Ultrasound Follow-Up Results

    International Nuclear Information System (INIS)

    Maleux, Geert; Bernaerts, Pauwel; Thijs, Vincent; Daenens, Kim; Vaninbroukx, Johan; Fourneau, Inge; Nevelsteen, Andre

    2003-01-01

    The purpose of this study was to evaluate the feasibility, safety and midterm outcome of elective implantation of the Carotid Wallstent (registered) in patients considered to be at high surgical risk. In a prospective study, 54 carotid artery stenoses in 51 patients were stented over a 24-month period. Three patients underwent bilateral carotid artery stenting. Institutional inclusion criteria for invasive treatment of carotid occlusive disease (carotid endarterectomy or carotid artery stenting) are patients presenting with a 70% or more symptomatic stenosis and those with an 80% or more asymptomatic stenosis having a life-expectancy of more than 1 year. All patients treated by carotid artery stenting were considered at high risk for carotid endarterectomy because of a hostile neck (17 patients-31.5%) or because of severe comorbidities (37 patients-68.5%). No cerebral protection device was used. Of the 54 lesions, 33 (61.1%) were symptomatic and 21 (38.8%) were asymptomatic. Follow-up was performed by physical examination and by duplex ultrasonography at 1 month, 6 months, 1 year and 2 years after the procedure. All 54 lesions could be stented successfully without periprocedural stroke. Advert events during follow-up (mean 13.9 ± 5.7 months) were non-stroke-related death in 6 patients (11.1%), minor stroke in 4 stented hemispheres(7.4%), transient ipsilateral facial pain in 1 patient (1.8%),infection of the stented surgical patch in 1 patient (1.8%) and asymptomatic in stent restenosis in 4 patients (7.4%). The percutaneous implantation of the Carotid Wallstent (registered) , even without cerebral protection device, appears to be a safe procedure with acceptable clinical and ultrasonographic follow-up results in patients at high surgical risk. But some late adverse events such as ipsilateral recurrence of non-disabling (minor) stroke or in stent restenosis still remain real challenging problems

  10. Hydrotalcites: a highly efficient ecomaterial for effluent treatment originated from carbon nanotubes chemical processing

    Energy Technology Data Exchange (ETDEWEB)

    Alves, O L; Stefani, D; Parizotto, N V; Filho, A G Souza, E-mail: oalves@iqm.unicamp.br [Solid State Chemistry Laboratory, Institute of Chemistry, University of Campinas - UNICAMP, P. O. Box 6154, 13083-970, Campinas-SP (Brazil)

    2011-07-06

    It has been reported that a mixture of carboxylated carbonaceous fragments (CCFs), so called oxidation debris, are generated during carbon nanotubes chemical processing using oxidant agents such as HNO{sub 3}. The elimination of these fragments from carbon nanotubes surface has been point out to be a crucial step for an effective functionalization of the nanotubes as well as for improving the material. However, this process can introduce a potential environmental problem related water contamination because these CCFs can be viewed as a mixture of carbonaceous polyaromatic systems similar to humic substances and dissolved organic matter (DOM). The negative aspects of humic substances and DOM to water quality and wastewater treatment are well known. Since carbon nanotubes industry expands at high rates it is expected that effluent containing oxidation debris will increase since HNO{sub 3} chemical processing is the most applied method for purification and functionalization of carbon nanotubes. In this work, we have demonstrated that Hydrotalcites (HT) are highly efficient to remove oxidation debris from effluent solution originated from HNO{sub 3}-treated multiwalled carbon nanotubes. The strategy presented here is a contribution towards green chemistry practices and life cycle studies in carbon nanotubes field.

  11. Carbon nanospheres derived from Lablab purpureus for high performance supercapacitor electrodes: a green approach.

    Science.gov (United States)

    Ali, Gomaa A M; Divyashree, A; Supriya, S; Chong, Kwok Feng; Ethiraj, Anita S; Reddy, M V; Algarni, H; Hegde, Gurumurthy

    2017-10-17

    Carbon nanospheres derived from a natural source using a green approach were reported. Lablab purpureus seeds were pyrolyzed at different temperatures to produce carbon nanospheres for supercapacitor electrode materials. The synthesized carbon nanospheres were analyzed using SEM, TEM, FTIR, TGA, Raman spectroscopy, BET and XRD. They were later fabricated into electrodes for cyclic voltammetry, galvanostatic charge/discharge and electrochemical impedance spectroscopy testing. The specific capacitances were found to be 300, 265 and 175 F g -1 in 5 M KOH electrolyte for carbon nanospheres synthesized at 800, 700 and 500 °C, respectively. These are on a par with those of prior electrodes made of biologically derived carbon nanospheres but the cycle lives were remarkably higher than those of any previous efforts. The electrodes showed 94% capacitance retention even after 5200 charge/discharge cycles entailing excellent recycling durability. In addition, the practical symmetrical supercapacitor showed good electrochemical behaviour under a potential window up to 1.7 V. This brings us one step closer to fabricating a commercial green electrode which exhibits high performance for supercapacitors. This is also a waste to wealth approach based carbon material for cost effective supercapacitors with high performance for power storage devices.

  12. Highly crystalline carbon dots from fresh tomato: UV emission and quantum confinement

    Science.gov (United States)

    Liu, Weijian; Li, Chun; Sun, Xiaobo; Pan, Wei; Yu, Guifeng; Wang, Jinping

    2017-12-01

    In this article, fresh tomatoes are explored as a low-cost source to prepare high-performance carbon dots by using microwave-assisted pyrolysis. Given that amino groups might act as nucleophiles for cleaving covalent bridging ester or ether in the crosslinked macromolecules in the biomass bulk, ethylenediamine (EDA) and urea with amino groups were applied as nucleophiles to modulate the chemical composites of the carbon nanoparticles in order to tune their fluorescence emission and enhance their quantum yields. Very interestingly, the carbon dots synthesized in the presence of urea had a highly crystalline nature, a low-degree amorphous surface and were smaller than 5 nm. Moreover, the doped N contributed to the formation of a cyclic form of core that resulted in a strong electron-withdrawing ability within the conjugated C plane. Therefore, this type of carbon dot exhibited marked quantum confinement, with the maximum fluorescence peak located in the UV region. Carbon nanoparticles greater than 20 nm in size, prepared using pristine fresh tomato and in the presence of EDA, emitted surface state controlled fluorescence. Additionally, carbon nanoparticles synthesized using fresh tomato pulp in the presence of EDA and urea were explored for bioimaging of plant pathogenic fungi and the detection of vanillin.

  13. 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.

    2010-01-01

    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. PMID:20573629

  14. Highly effective catalytic peroxymonosulfate activation on N-doped mesoporous carbon for o-phenylphenol degradation.

    Science.gov (United States)

    Hou, Jifei; Yang, Shasha; Wan, Haiqin; Fu, Heyun; Qu, Xiaolei; Xu, Zhaoyi; Zheng, Shourong

    2018-04-01

    As a broad-spectrum preservative, toxic o-phenylphenol (OPP) was frequently detected in aquatic environments. In this study, N-doped mesoporous carbon was prepared by a hard template method using different nitrogen precursors and carbonization temperatures (i.e., 700, 850 and 1000 °C), and was used to activate peroxymonosulfate (PMS) for OPP degradation. For comparison, mesoporous carbon (CMK-3) was also prepared. Characterization results showed that the N-doped mesoporous carbon samples prepared under different conditions were perfect replica of their template. In comparison with ethylenediamine (EDA) and dicyandiamide (DCDA) as the precursors, N-doped mesoporous carbon prepared using EDA and carbon tetrachloride as the precursors displayed a higher catalytic activity for OPP degradation. Increasing carbonization temperature of N-doped mesoporous carbon led to decreased N content and increased graphitic N content at the expense of pyridinic and pyrrolic N. Electron paramagnetic resonance (EPR) analysis showed that PMS activation on N-doped mesoporous carbon resulted in highly active species and singlet oxygen, and catalytic PMS activation for OPP degradation followed a combined radical and nonradical reaction mechanism. Increasing PMS concentration enhanced OPP degradation, while OPP degradation rate was independent on initial OPP concentration. Furthermore, the dependency of OPP degradation on PMS concentration followed the Langmuir-Hinshelwood model, reflecting that the activation of adsorbed PMS was the rate controlling step. Based on the analysis by time-of-flight mass spectrometry, the degradation pathway of OPP was proposed. Copyright © 2018 Elsevier Ltd. All rights reserved.

  15. Nanoscale Soldering of Positioned Carbon Nanotubes using Highly Conductive Electron Beam Induced Gold Deposition

    DEFF Research Database (Denmark)

    Madsen, Dorte Nørgaard; Mølhave, Kristian; Mateiu, Ramona Valentina

    2003-01-01

    We have developed an in-situ method for controlled positioning of carbon nanotubes followed by highly conductive contacting of the nanotubes, using electron beam assisted deposition of gold. The positioning and soldering process takes place inside an Environmental Scanning Electron Microscope (E...... in a carbon matrix. Nanoscale soldering of multi-walled carbon nanotubes (MWNT) onto microelectrodes was achieved by deposition of a conducting gold line across a contact point between nanotube and electrode. The solderings were found to be mechanically stronger than the carbon nanotubes. We have positioned...... MWNTs to bridge the gap between two electrodes, and formed soldering bonds between the tube and each of the electrodes. All nanotube bridges showed ohmic resistances in the range 10-30 kΩ. We observed no increase in resistance after exposing the MWNT bridge to air for days....

  16. 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...

  17. The study on density change of carbon dioxide seawater solution at high pressure and low temperature

    International Nuclear Information System (INIS)

    Song, Y.; Chen, B.; Nishio, M.; Akai, M.

    2005-01-01

    It has been widely considered that the global warming, induced by the increasing concentration of carbon dioxide and other greenhouse gases in the atmosphere, is an environmental task affecting the world economic development. In order to mitigate the concentration of CO 2 in the atmosphere, the sequestration of carbon dioxide into the ocean had been investigated theoretically and experimentally over the last 10 years. In addition to ocean dynamics, ocean geological, and biological information on large space and long time scales, the physical-chemistry properties of seawater-carbon dioxide system at high pressure (P>5.0 MPa) and lower temperature (274.15 K 3 , which is approximately same with that of carbon dioxide freshwater solution, the slope of which is 0.275 g/cm 3

  18. Zero- and two-dimensional hybrid carbon phosphors for high colorimetric purity white light-emission.

    Science.gov (United States)

    Ding, Yamei; Chang, Qing; Xiu, Fei; Chen, Yingying; Liu, Zhengdong; Ban, Chaoyi; Cheng, Shuai; Liu, Juqing; Huang, Wei

    2018-03-01

    Carbon nanomaterials are promising phosphors for white light emission. A facile single-step synthesis method has been developed to prepare zero- and two-dimensional hybrid carbon phosphors for the first time. Zero-dimensional carbon dots (C-dots) emit bright blue luminescence under 365 nm UV light and two-dimensional nanoplates improve the dispersity and film forming ability of C-dots. As a proof-of-concept application, the as-prepared hybrid carbon phosphors emit bright white luminescence in the solid state, and the phosphor-coated blue LEDs exhibit high colorimetric purity white light-emission with a color coordinate of (0.3308, 0.3312), potentially enabling the successful application of white emitting phosphors in the LED field.

  19. High-speed logic integrated circuits with solution-processed self-assembled carbon nanotubes.

    Science.gov (United States)

    Han, Shu-Jen; Tang, Jianshi; Kumar, Bharat; Falk, Abram; Farmer, Damon; Tulevski, George; Jenkins, Keith; Afzali, Ali; Oida, Satoshi; Ott, John; Hannon, James; Haensch, Wilfried

    2017-09-01

    As conventional monolithic silicon technology struggles to meet the requirements for the 7-nm technology node, there has been tremendous progress in demonstrating the scalability of carbon nanotube field-effect transistors down to the size that satisfies the 3-nm node and beyond. However, to date, circuits built with carbon nanotubes have overlooked key aspects of a practical logic technology and have stalled at simple functionality demonstrations. Here, we report high-performance complementary carbon nanotube ring oscillators using fully manufacturable processes, with a stage switching frequency of 2.82 GHz. The circuit was built on solution-processed, self-assembled carbon nanotube arrays with over 99.9% semiconducting purity, and the complementary feature was achieved by employing two different work function electrodes.

  20. High-speed logic integrated circuits with solution-processed self-assembled carbon nanotubes

    Science.gov (United States)

    Han, Shu-Jen; Tang, Jianshi; Kumar, Bharat; Falk, Abram; Farmer, Damon; Tulevski, George; Jenkins, Keith; Afzali, Ali; Oida, Satoshi; Ott, John; Hannon, James; Haensch, Wilfried

    2017-09-01

    As conventional monolithic silicon technology struggles to meet the requirements for the 7-nm technology node, there has been tremendous progress in demonstrating the scalability of carbon nanotube field-effect transistors down to the size that satisfies the 3-nm node and beyond. However, to date, circuits built with carbon nanotubes have overlooked key aspects of a practical logic technology and have stalled at simple functionality demonstrations. Here, we report high-performance complementary carbon nanotube ring oscillators using fully manufacturable processes, with a stage switching frequency of 2.82 GHz. The circuit was built on solution-processed, self-assembled carbon nanotube arrays with over 99.9% semiconducting purity, and the complementary feature was achieved by employing two different work function electrodes.

  1. A 66 fs highly stable single wall carbon nanotube mode locked fiber laser

    International Nuclear Information System (INIS)

    Yu, Zhenhua; Zhang, Xiao; Dong, Xinzheng; Tian, Jinrong; Song, Yanrong; Wang, Yonggang

    2014-01-01

    We demonstrate a highly stable mode locked fiber laser based on single wall carbon nanotubes. The mode locking is achieved by the evanescent field interaction of the propagating light with a single wall carbon nanotube saturable absorber in a microfiber. The pulse width is 66 fs, which, to the best of our knowledge, is the shortest pulse achieved in a carbon nanotube mode locked fiber laser. The maximum average output power is 26 mW, which is about 20 times larger than that of a typical carbon nanotube mode locked fiber laser. The center of the wavelength is 1555 nm, with 54 nm spectral width. The repetition rate is 146 MHz. To investigate the laser’s stability, the output pulses are monitored for 120 h and there is no significant degradation of the laser spectral width or shape. (paper)

  2. Modelling of drawing and rolling of high carbon flat wires

    International Nuclear Information System (INIS)

    Bobadilla, C.; Persem, N.; Foissey, S.

    2007-01-01

    In order to meet customer requirements, it is necessary to develop new flat wires with a high tensile strength and a high width/thickness ratio. These products are manufactured from wire rod. The first step is to draw the wire until we have the required mechanical properties and required surface area of the section. After this, the wire is rolled from a round to a rectangular section. During the flat rolling process it can be reduced by more than 50%. Then the wire is exposed to a high level of stress during this process. Modelling allows us to predetermine this stress level, taking into account the final dimensions and the mechanical properties, thus optimising both rolling and drawing process. Forge2005 was used in order to simulate these processes. The aim of this study is to determine the value of residual stresses after drawing and so to optimise rolling. Indeed, the highest stress values are reached at this step of the process by changing the section of the wire from a round to a rectangular one. In order to evaluate the stress value accuracy for high strain levels, a behaviour law has been identified. This is a result of tensile tests carried out at each step of the drawing process. Finally, a multi-axial damage criterion was implemented using Forge2005. The optimisation of the rolling is directly linked to the minimisation of this criterion

  3. Highly stressed carbon film coatings on silicon potential applications

    CERN Multimedia

    Sharda, T

    2002-01-01

    The fabrication of highly stressed and strongly adhered nanocrystalline diamond films on Si substrates is presented. A microwave plasma CVD method with controlled and continuous bias current density was used to grow the films. The stress/curvature of the films can be varied and controlled by altering the BCD. Potential applications for these films include particle physics and x-ray optics.

  4. Laser cladding process development for high carbon steel substrates

    CSIR Research Space (South Africa)

    Lengopeng, T

    2014-11-01

    Full Text Available 316L as a butter layer did not lead to the formation of hard brittle chromium carbides even though the chromium content is high enough for the formation of these stable carbides. It was however observed that the use of an AISI 316L butter layer did...

  5. High spatial resolution and high contrast visualization of brain arteries and veins. Impact of blood pool contrast agent and water-selective excitation imaging at 3T

    International Nuclear Information System (INIS)

    Spuentrup, E.; Jacobs, J.E.; Kleimann, J.F.

    2010-01-01

    Purpose: To investigate a blood pool contrast agent and water-selective excitation imaging at 3 T for high spatial and high contrast imaging of brain vessels including the veins. Methods and Results: 48 clinical patients (47 ± 18 years old) were included. Based on clinical findings, twenty-four patients received a single dose of standard extracellular Gadoterate-meglumine (Dotarem registered ) and 24 received the blood pool contrast agent Gadofosveset (Vasovist registered ). After finishing routine MR protocols, all patients were investigated with two high spatial resolution (0.15 mm 3 voxel size) gradient echo sequences in random order in the equilibrium phase (steady-state) as approved by the review board: A standard RF-spoiled gradient-echo sequence (HR-SS, TR/TE 5.1 / 2.3 msec, FA 30 ) and a fat-suppressed gradient-echo sequence with water-selective excitation (HR-FS, 1331 binominal-pulse, TR/TE 8.8 / 3.8 msec, FA 30 ). The images were subjectively assessed (image quality with vessel contrast, artifacts, depiction of lesions) by two investigators and contrast-to-noise ratios (CNR) were compared using the Student's t-test. The image quality and CNR in the HR-FS were significantly superior compared to the HR-SS for both contrast agents (p < 0.05). The CNR was also improved when using the blood pool agent but only to a minor extent while the subjective image quality was similar for both contrast agents. Conclusion: The utilized sequence with water-selective excitation improved image quality and CNR properties in high spatial resolution imaging of brain arteries and veins. The used blood pool contrast agent improved the CNR only to a minor extent over the extracellular contrast agent. (orig.)

  6. Polyfurfuryl alcohol derived activated carbons for high power electrical double layer capacitors

    International Nuclear Information System (INIS)

    Ruiz, V.; Pandolfo, A.G.

    2010-01-01

    Polyfurfuryl alcohol (PFA) derived activated carbons were prepared by the acid catalysed polymerization of furfuryl alcohol, followed by potassium hydroxide activation. Activated carbons with apparent BET surface areas ranging from 1070 to 2600 m 2 g -1 , and corresponding average micropore sizes between 0.6 and 1.6 nm were obtained. The porosity of these carbons can be carefully controlled during activation and their performance as electrode materials in electric double layer capacitors (EDLCs) in a non-aqueous electrolyte (1 M Et 4 NBF 4 /ACN) is investigated. Carbon materials with a low average pore size ( -1 at an operating voltage window of 0-2.5 V; which corresponds to 32 Wh kg -1 and 38 kW kg -1 on an active material basis. These carbons also displayed an outstanding performance at high current densities delivering up to 100 F g -1 at current densities as high as 250 A g -1 . The exceptionally high capacitance and power of this electrode material is attributed to its good electronic conductivity and a highly effective combination of micro- and fine mesoporosity.

  7. Carbon Bioavailability in a High Arctic Fjord Influenced by Glacial Meltwater, NE Greenland

    Directory of Open Access Journals (Sweden)

    Maria L. Paulsen

    2017-06-01

    Full Text Available The land-to-ocean flux of organic carbon is increasing in glacierized regions in response to increasing temperatures in the Arctic (Hood et al., 2015. In order to understand the response of the coastal ecosystem metabolism to the organic carbon input it is essential to determine the bioavailability of the different carbon sources in the system. We quantified the bacterial turnover of organic carbon in a high Arctic fjord system (Young Sound, NE Greenland during the ice-free period (July-October 2014 and assessed the quality and quantity of the 3 major organic carbon sources; (1 local phytoplankton production (2 runoff from land-terminating glaciers and a lowland river and (3 inflow from the ocean shelf. We found that despite relatively low concentrations of DOC in the rivers, the bioavailability of the river–DOC was significantly higher than in the fjord, and characterized by high cell-specific bacterial production and low C:N ratios. In contrast, the DOC source entering via inflow of coastal shelf waters had high DOC concentrations with high C:N and low specific bacterial production. The phytoplankton production in the fjord could not sustain the bacterial carbon demand, but was still the major source of organic carbon for bacterial growth. We assessed the bacterial community composition and found that communities were specific for the different water types i.e., the bacterial community of the coastal inflow water could be traced mainly in the subsurface water, while the glacial river community strongly dominated the surface water in the fjord.