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Carbon dioxide

Peter R Worsley, Dan Rebolledo, Sally Webb, Silvia Caggiari, Dan L Bader
BACKGROUND: Individuals with limited mobility can spend prolonged periods in leisure chairs, increasing their risk of developing a seated acquired pressure ulcer. The present study aims to use objective measures of posture and tissue viability to identify the associated risks of leisure chair related pressure ulcers. METHODS: Healthy participants (n = 13) were recruited to sit on a leisure chair with either a viscoelastic foam or air cushion. Participants were asked to adopt four different postures for a period of 10 min followed by a 10 min refractory period...
October 12, 2017: Journal of Tissue Viability
Shu-Xian Li, Chang-Zhou Chen, Ming-Fei Li, Xiao Xiao
Corncob was torrefied under nitrogen and carbon dioxide atmospheres at 220-300 °C, obtaining solid products with mass yields of 69.38-95.03% and 67.20-94.99% and higher heating values of 16.58-24.77 MJ/kg and 16.68-24.10 MJ/kg, respectively. The changes of physicochemical properties of the charcoal was evaluated by many spectroscopies, contact angle determination, and combustion test. Hemicelluloses were not detected for the torrefaction under the hard conditions. As the severity increased, C concentration raised while H and O concentrations reduced...
October 12, 2017: Bioresource Technology
Isabel Pestana da Paixão Cansado, Cristóvão Ramiro Belo, Paulo Alexandre Mira Mourão
This work presents a first approach concerning the use of Tectona Grandis tree sawdust (from East Timor) for high activated carbon production, by physical activation with carbon dioxide at different temperatures. The activated carbons (AC) obtained exhibit a well-developed porous structure with a pore size distribution varying from micro to mesopores. Selected AC was successfully evaluated for pesticide removal, specific to 4-chloro-2-methylphenoxyacetic acid, from the liquid phase. The results presented are very promising, allowing to establish that Tectona Grandis sawdust is as an excellent precursor for the basic AC production and allow to expect good performance of theses adsorbents on the removal of a broad range of pollutants...
October 10, 2017: Bioresource Technology
Sung-Eun Kim, Jun Ho Lee, Tae Gon Kim, Yong-Ha Kim, Kyu Jin Chung
BACKGROUND: Fat grafting is a commonly performed procedure not only for augmenting the soft tissue but also for regeneration in esthetic and reconstructive plastic surgery.However, unpredictable fat survival rate because of high resorption rate is remained as the main problem. The purpose of this study was to investigate the effect of pretreatment of the recipient site to the fat survival using fractional carbon dioxide (CO2) laser. METHODS: The rats were divided to 2 groups...
October 19, 2017: Annals of Plastic Surgery
Robert B Balow, Jeffrey G Lundin, Grant C Daniels, Wesley O Gordon, Monica McEntee, Gregory W Peterson, James H Wynne, Pehr E Pehrsson
Zirconium hydroxide (Zr(OH)4) has excellent sorption properties and wide-ranging reactivity towards numerous types of chemical warfare agents (CWAs) and toxic industrial chemicals. Under pristine laboratory conditions, the effectiveness of Zr(OH)4 has been attributed to a combination of diverse surface hydroxyl species and defects; however, atmospheric components (e.g. CO2, H2O, etc.) and trace contaminants can form adsorbates with potentially detrimental impact to the chemical reactivity of Zr(OH)4. Here, we report the hydrolysis of a chemical warfare agent simulant, dimethyl methylphosphonate (DMMP) on Zr(OH)4 determined by gas chromatography mass spectrometry and in situ attenuated total reflectance Fourier transform infrared spectroscopy under ambient conditions...
October 20, 2017: ACS Applied Materials & Interfaces
William Dudefoi, Hélène Terrisse, Aurelian Florin Popa, Eric Gautron, Bernard Humbert, Marie-Hélène Ropers
Titanium dioxide is a metal oxide used as a white pigment in many food categories, including confectionery. Due to differences in the mass fraction of nanoparticles contained in TiO2, the estimated intakes of TiO2 nanoparticles differ by a factor of 10 in the literature. To resolve this problem, a better estimation of the mass of nanoparticles present in food products is needed. In this study, we focused our efforts on chewing gum, which is one of the food products contributing most to the intake of TiO2. The coatings of four kinds of chewing gum, where the presence of TiO2 was confirmed by Raman spectroscopy, were extracted in aqueous phases...
October 20, 2017: Food Additives & Contaminants. Part A, Chemistry, Analysis, Control, Exposure & Risk Assessment
Hong Zhong, Yanqing Su, Xingwei Chen, Xiaoju Li, Ruihu Wang
Carbon dioxide (CO2) adsorption and concomitant catalytic conversion into useful chemicals are promising approaches to alleviate energy crisis and global warming. It is highly desirable for developing new types of heterogeneous catalytic materials containing CO2-philic groups and catalytic active sites for CO2 chemical transformation. Here, we present an imidazolium- and triazine-based porous organic polymer with counter chloride anion (IT-POP-1). The porosity and CO2 affinity of IT-POP-1 may be modulated at molecular level through facile anion exchange strategy...
October 20, 2017: ChemSusChem
Satish Kumar Iyemperumal, N Aaron Deskins
Catalytic reduction of carbon dioxide to useful chemicals is a potent way to mitigate this greenhouse gas, but the challenge lies in finding active reduction catalysts. Using density functional theory we studied CO2 activation over TiO2-supported Cu clusters of size 1-4 atoms. The linear to bent transformation of CO2 is necessary for activation, and we found that all the clusters stabilized bent CO2, along with a significant gain of electrons on the CO2 (indicative of activation). On all the TiO2 supported Cu clusters, the interfacial sites were found to stabilize the bent CO2 adsorption, where the active site of adsorption on Cu dimer, trimer and tetramer was on the Cu atom farthest away from the TiO2 surface...
October 20, 2017: Physical Chemistry Chemical Physics: PCCP
James R Sackett, Zachary J Schlader, Suman Sarker, Christopher L Chapman, Blair D Johnson
Carbon dioxide (CO2) retention occurs during water immersion, but it is not known if peripheral chemosensitivity is altered during water immersion, which could contribute to CO2 retention. We tested the hypothesis that peripheral chemosensitivity to hypercapnia and hypoxia is blunted during 2 h of thermoneutral head out water immersion (HOWI) in healthy young adults. Peripheral chemosensitivity was assessed by the ventilatory, heart rate, and blood pressure responses to hypercapnia and hypoxia at baseline, 10, 60, 120 min, and post HOWI and a time-control visit (control)...
November 2017: Physiological Reports
Kênia C Bícego, Jacopo P Mortola
Many adult mammals and birds respond to heat with thermal tachypnea, an increase in breathing frequency with shallow tidal volume, with minimal increase in oxygen consumption (V̇O2 ). This pattern favors heat dissipation by evaporative water loss (EWL) through the respiratory tract. We asked to what extent this response was apparent at the earliest stages of development, when pulmonary ventilation (V̇E) initiates. Measurements of V̇E(barometric technique), V̇O2 (open-flow methodology) and EWL (water scrubbers) were performed on chicken embryos at the earliest appearance of V̇E, during the internal pipping stage...
October 19, 2017: Journal of Experimental Biology
Victor D Mandel, Federica Arginelli, Giovanni Pellacani, Maurizio Greco
No abstract text is available yet for this article.
December 2017: Giornale Italiano di Dermatologia e Venereologia: Organo Ufficiale, Società Italiana di Dermatologia e Sifilografia
C Y Ou, H Ran, L Qiu, Z D Huang, Z Z Lin, J Deng, W B Liu
Objective: To investigate the clinical features of the Pre-Crisis State and analyze the correlated risk factors of Pre-Crisis State of myasthenia crisis. Methods: We included 93 patients with myasthenia gravis (MG) who experienced 127 times Pre-Crisis State between October 2007 and July 2016. Those patients were hospitalized in the MG specialize center, Department of Neurological Science, first Affiliated Hospital of Sun Yat-sen University. The information of the general situation, the clinical manifestations and the blood gas analysis in those patients were collected using our innovated clinical research form...
October 10, 2017: Zhonghua Yi Xue za Zhi [Chinese medical journal]
Nicholas Teo, Sadhan C Jana
Water-in-oil emulsion-templating method is used in this work for fabrication of open cell aerogel foams from syndiotactic polystyrene (sPS). A surfactant-stabilized emulsion is prepared at 60 C-100 C by dispersing water in a solution of sPS in toluene. sPS gel, formed upon cooling of the emulsion to room temperature, locks the water droplets inside the gel. The gel is solvent exchanged in ethanol and then dried under supercritical condition of carbon dioxide to yield the aerogel foams. The aerogel foams show significant fraction of macropores of diameter of a few tens of micrometer, defined as macrovoids that originated from the emulsified water droplets...
October 19, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
Juan Du, Yadan Zhu, Shiguang Li, Junxuan Zhang, Yanguang Sun, Huaguo Zang, Dan Liu, Xiuhua Ma, Decang Bi, Jiqiao Liu, Xiaolei Zhu, Weibiao Chen
A ground-based double-pulse integrated path differential absorption (IPDA) instrument for carbon dioxide (CO2) concentration measurements at 1572 nm has been developed. A ground experiment was implemented under different conditions with a known wall located about 1.17 km away acting as the scattering hard target. Off-/offline testing of a laser transmitter was conducted to estimate the instrument systematic and random errors. Results showed a differential absorption optical depth (DAOD) offset of 0.0046 existing in the instrument...
September 1, 2017: Applied Optics
Upendra N Singh, Tamer F Refaat, Syed Ismail, Kenneth J Davis, Stephan R Kawa, Robert T Menzies, Mulugeta Petros
Sustained high-quality column carbon dioxide (CO2) atmospheric measurements from space are required to improve estimates of regional and continental-scale sources and sinks of CO2. Modeling of a space-based 2 μm, high pulse energy, triple-pulse, direct detection integrated path differential absorption (IPDA) lidar was conducted to demonstrate CO2 measurement capability and to evaluate random and systematic errors. Parameters based on recent technology developments in the 2 μm laser and state-of-the-art HgCdTe (MCT) electron-initiated avalanche photodiode (e-APD) detection system were incorporated in this model...
August 10, 2017: Applied Optics
Axel Amediek, Gerhard Ehret, Andreas Fix, Martin Wirth, Christian Büdenbender, Mathieu Quatrevalet, Christoph Kiemle, Christoph Gerbig
The integrated-path differential-absorption lidar CHARM-F (CO2 and CH4 Remote Monitoring-Flugzeug) was developed for the simultaneous measurement of the greenhouse gases CO2 and CH4 onboard the German research aircraft HALO (High Altitude and Long Range Research Aircraft). The purpose is to derive the weighted, column-averaged dry-air mixing ratios of the two gases with high precision and accuracy between aircraft and ground or cloud tops. This paper presents the first measurements, performed in the spring of 2015, and shows performance analyses as well as the methodology for the quantification of strong point sources applied on example cases...
June 20, 2017: Applied Optics
C Lyons, M Callaghan
Surgery under apnoeic conditions with the use of high-flow nasal oxygen is novel. Between November 2016 and May 2017, 28 patients underwent tubeless laryngeal or tracheal surgery under apnoeic conditions with high-flow nasal oxygen as the sole method of gas exchange. Patients received total intravenous anaesthesia and neuromuscular blocking agents for the duration of their surgery. The median (IQR [range]) apnoea time was 19 (15-24 [9-37]) min. Four patients experienced an episode of oxygen desaturation to a value between 85% and 90%, lasting less than 2 min in each case...
November 2017: Anaesthesia
Kevin J Wolz, Timothy M Wertin, Mark Abordo, Dan Wang, Andrew D B Leakey
Stomatal pores on leaf surfaces respond to environmental and physiological signals to regulate leaf gas exchange. Mathematical models can predict stomatal conductance (g s), with one parameter (m or g l) reflecting the sensitivity of g s to the photosynthetic rate (A), atmospheric carbon dioxide concentration and atmospheric humidity, and a second parameter (g 0) representing the minimum g s. Such models are solved iteratively with a photosynthesis model to form the core of many models of crop or ecosystem carbon and water fluxes...
September 2017: Nature ecology & evolution
Ling-Yang Xu, Ding Xu
The key to the treatment of septic shock is to provide adequate oxygen supply and improve tissue perfusion. Lactate and central venous oxygen saturation (ScvO2) are commonly used as the indices of oxygen metabolism, but tissue hypoxia may still exist even when lactate and ScvO2 are within the normal range. Arteriovenous difference in carbon dioxide partial pressure (CO2 gap) can accurately reflect oxygen delivery when ScvO2 is in the normal range. This article reviews the advantages and shortages of lactate, lactate clearance rate, ScvO2, and CO2 gap in evaluating tissue hypoxia, in order to provide a reference for treatment and severity evaluation of septic shock...
October 2017: Zhongguo Dang Dai Er Ke za Zhi, Chinese Journal of Contemporary Pediatrics
Sheng Hui, Jonathan M Ghergurovich, Raphael J Morscher, Cholsoon Jang, Xin Teng, Wenyun Lu, Lourdes A Esparza, Tannishtha Reya, Le Zhan, Jessie Yanxiang Guo, Eileen White, Joshua D Rabinowitz
Mammalian tissues are fuelled by circulating nutrients, including glucose, amino acids, and various intermediary metabolites. Under aerobic conditions, glucose is generally assumed to be burned fully by tissues via the tricarboxylic acid cycle (TCA cycle) to carbon dioxide. Alternatively, glucose can be catabolized anaerobically via glycolysis to lactate, which is itself also a potential nutrient for tissues and tumours. The quantitative relevance of circulating lactate or other metabolic intermediates as fuels remains unclear...
October 18, 2017: Nature
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