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https://www.readbyqxmd.com/read/28823034/effect-of-pristine-and-functionalized-single-and-multi-walled-carbon-nanotubes-on-co2-separation-of-mixed-matrix-membranes-based-on-polymers-of-intrinsic-microporosity-pim-1-a-molecular-dynamics-simulation-study
#1
Karim Golzar, Hamid Modarress, Sepideh Amjad-Iranagh
Molecular dynamics (MD) and grand canonical Monte Carlo (GCMC) simulations were conducted to investigate the transport properties of carbon dioxide, methane, nitrogen, and oxygen through pure and mixed matrix membranes (MMMs) based on polymers of intrinsic microporosity (PIM-1). For this purpose, first, 0.5 to 3 wt% of pristine single-walled carbon nanotube (p-SWCNT) and multi-walled carbon nanotube (p-MWCNT) were embedded into the pure PIM-1, and then for better dispersion of CNT particles into the polymer matrix and to improve the performance of the resulting MMMs, polyethylene glycol (PEG) functionalized SWCNT and MWCNT (f-SWCNT and f-MWCNT, respectively) were loaded...
August 19, 2017: Journal of Molecular Modeling
https://www.readbyqxmd.com/read/28821870/enhanced-silicon-availability-leads-to-increased-methane-production-nutrient-and-toxicant-mobility-in-peatlands
#2
Gloria-Maria Susanne Reithmaier, Klaus-Holger Knorr, Sebastian Arnhold, Britta Planer-Friedrich, Jörg Schaller
Peatlands perform important ecosystem functions, such as carbon storage and nutrient retention, which are affected, among other factors, by vegetation and peat decomposition. The availability of silicon (Si) in peatlands differs strongly, ranging from <1 to >25 mg L(-1). Since decomposition of organic material was recently shown to be accelerated by Si, the aim of this study was to examine how Si influences decomposition of carbon and nutrient and toxicant mobilization in peatlands. We selected a fen site in Northern Bavaria with naturally bioavailable Si pore water concentrations of 5 mg/L and conducted a Si addition experiment...
August 18, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28820945/a-chiral-gas-hydrate-structure-common-to-the-carbon-dioxide-water-and-hydrogen-water-systems
#3
Dan Amos, Mary-Ellen Donnelly, Pattanasak Teeratchanan, Craig L Bull, Andrzej Falenty, Werner F Kuhs, Andreas Hermann, John Loveday
We present diffraction studies and full in-situ structural solutions of carbon dioxide hydrate-II and hydrogen hydrate $C_0$ at elevated pressures. We find both hydrates adopt a common water network structure. The structure exhibits several features not previously found in hydrates, most notably it is chiral and has large open spiral channels along which the guest molecules are free to move. It has a network that is unrelated to any experimentally known ice, silica or zeolite network but is instead related to two Zintl compounds...
August 18, 2017: Journal of Physical Chemistry Letters
https://www.readbyqxmd.com/read/28819793/the-mechanisms-underlying-the-production-of-discontinuous-gas-exchange-cycles-in-insects
#4
REVIEW
Philip G D Matthews
This review examines the control of gas exchange in insects, specifically examining what mechanisms could explain the emergence of discontinuous gas exchange cycles (DGCs). DGCs are gas exchange patterns consisting of alternating breath-hold periods and bouts of gas exchange. While all insects are capable of displaying a continuous pattern of gas exchange, this episodic pattern is known to occur within only some groups of insects and then only sporadically or during certain phases of their life cycle. Investigations into DGCs have tended to emphasise the role of chemosensory thresholds in triggering spiracle opening as critical for producing these gas exchange patterns...
August 17, 2017: Journal of Comparative Physiology. B, Biochemical, Systemic, and Environmental Physiology
https://www.readbyqxmd.com/read/28819714/utilization-of-waste-bittern-from-saltern-as-a-source-for-magnesium-and-an-absorbent-for-carbon-dioxide-capture
#5
Choon-Ki Na, Hyunju Park, Eun Hea Jho
During solar salt production, large quantities of bittern, a liquid by-product containing high inorganic substance concentrations, are produced. The purpose of this research was to examine the utilization of waste bittern generated from salterns as a source for Mg production and as an absorbent for carbon dioxide (CO2) capture. The study was conducted in a sequential two-step process. At NaOH/Mg molar ratios of 2.70-2.75 and pH 9.5-10.0, > 99% Mg precipitation from the bittern was achieved. After washing with water, 100-120 g/L of precipitate containing 94% Mg(OH)2 was recovered from the bittern...
August 18, 2017: Environmental Science and Pollution Research International
https://www.readbyqxmd.com/read/28818947/methanogenic-heterodisulfide-reductase-hdrabc-mvhagd-uses-two-noncubane-4fe-4s-clusters-for-reduction
#6
Tristan Wagner, Jürgen Koch, Ulrich Ermler, Seigo Shima
In methanogenic archaea, the carbon dioxide (CO2) fixation and methane-forming steps are linked through the heterodisulfide reductase (HdrABC)-[NiFe]-hydrogenase (MvhAGD) complex that uses flavin-based electron bifurcation to reduce ferredoxin and the heterodisulfide of coenzymes M and B. Here, we present the structure of the native heterododecameric HdrABC-MvhAGD complex at 2.15-angstrom resolution. HdrB contains two noncubane [4Fe-4S] clusters composed of fused [3Fe-4S]-[2Fe-2S] units sharing 1 iron (Fe) and 1 sulfur (S), which were coordinated at the CCG motifs...
August 18, 2017: Science
https://www.readbyqxmd.com/read/28818484/the-physiology-of-submaximal-exercise-the-steady-state-concept
#7
REVIEW
Guido Ferretti, Nazzareno Fagoni, Anna Taboni, Paolo Bruseghini, Giovanni Vinetti
The steady state concept implies that the oxygen flow is invariant and equal at each level along the respiratory system. The same is the case with the carbon dioxide flow. This condition has several physiological consequences, which are analysed. First, we briefly discuss the mechanical efficiency of exercise and the energy cost of human locomotion, as well as the roles played by aerodynamic work and frictional work. Then we analyse the equations describing the oxygen flow in lungs and in blood, the effects of ventilation and of the ventilation - perfusion inequality, and the interaction between diffusion and perfusion in the lungs...
August 14, 2017: Respiratory Physiology & Neurobiology
https://www.readbyqxmd.com/read/28818140/dynamic-cerebral-autoregulation-during-the-combination-of-mild-hypercapnia-and-cephalad-fluid-shift
#8
Takuya Kurazumi, Yojiro Ogawa, Ryo Yanagida, Hiroshi Morisaki, Ken-Ichi Iwasaki
BACKGROUND: Mild hypercapnia combined with a cephalad fluid shift [e.g., that occurring during spaceflight or laparoscopic surgery with head-down tilt (HDT)] might affect cerebral autoregulation. However, no reports have described the effects of the combination on dynamic cerebral autoregulation. Therefore, we tested the hypothesis that the combination of mild hypercapnia and a cephalad fluid shift would attenuate dynamic cerebral autoregulation. METHODS: There were 15 healthy male volunteers who were exposed to 4 10-min protocols in which they received air in the supine position (Placebo/Supine), 3% carbon dioxide (CO2) in the supine position (CO2/Supine), air with -10° HDT (Placebo/HDT) and 3% CO2 with -10° HDT (CO2/HDT)...
September 1, 2017: Aerospace Medicine and Human Performance
https://www.readbyqxmd.com/read/28817882/re-warmed-and-humidified-carbon-dioxide-for-abdominal-laparoscopic-surgery-meta-analysis-of-the-current-literature
#9
Jeffrey A Cadeddu
No abstract text is available yet for this article.
September 2017: Journal of Urology
https://www.readbyqxmd.com/read/28817401/challenges-in-the-anesthetic-management-of-ambulatory-patients-in-the-mri-suites
#10
Jasper Deen, Yzabel Vandevivere, Peter Van de Putte
PURPOSE OF REVIEW: MRI is becoming an indispensable diagnostic tool. The need for prolonged motion-free periods has substantially increased the need for deep sedation or anesthesia in a challenging environment. This review summarises recent literature with respect to pharmacological sedative strategies, nonpharmacological alternative approaches, airway management and safety issues in the ambulatory setting. RECENT FINDINGS: Most literature researches the pediatric patient population...
August 16, 2017: Current Opinion in Anaesthesiology
https://www.readbyqxmd.com/read/28817275/influence-of-sodium-chloride-on-the-formation-and-dissociation-behavior-of-co2-gas-hydrates
#11
Christine Carola Holzammer, Judith Maria Schicks, Stefan Will, Andreas Siegfried Braeuer
We present an experimental study on the formation and dissociation characteristics of carbon dioxide (CO2) gas hydrates using Raman spectroscopy. The CO2 hydrates were formed from sodium-chloride/water solutions with salinities of 0-10 wt-%, which were pressurized with liquid CO2 in a stirred vessel at 6 MPa and a subcooling of 9.5 K. The formation of the CO2 hydrate resulted in a hydrate gel where the solid hydrate can be considered as the continuous phase that includes small amounts of a dispersed liquid water-rich phase that has not been converted to hydrate...
August 17, 2017: Journal of Physical Chemistry. B
https://www.readbyqxmd.com/read/28815998/architects-of-nature-growing-buildings-with-bacterial-biofilms
#12
Martyn Dade-Robertson, Alona Keren-Paz, Meng Zhang, Ilana Kolodkin-Gal
In his text 'On Architecture', Vitruvius suggested that architecture is an imitation of nature. Here we discuss what happens when we begin using nature in architecture. We describe recent developments in the study of biofilm structure, and propose combining modern architecture and synthetic microbiology to develop sustainable construction approaches. Recently, Kolodkin-Gal laboratory and others revealed a role for precipitation of calcium carbonate in the maturation and assembly of bacterial communities with complex structures...
August 16, 2017: Microbial Biotechnology
https://www.readbyqxmd.com/read/28815992/the-spatial-distribution-of-soil-organic-carbon-in-tidal-wetland-soils-of-the-continental-united-states
#13
Audra L Hinson, Rusty A Feagin, Marian Eriksson, Raymond G Najjar, Maria Herrmann, Thomas S Bianchi, Michael Kemp, Jack A Hutchings, Steve Crooks, Thomas Boutton
Tidal wetlands contain large reservoirs of carbon in their soils and can sequester carbon dioxide (CO2 ) at a greater rate per unit area than nearly any other ecosystem. The spatial distribution of this carbon influences climate and wetland policy. To assist with international accords such as the Paris Climate Agreement, national-level assessments such as the United States (U.S.) National Greenhouse Gas Inventory, and regional, state, local, and project-level evaluation of CO2 sequestration credits, we developed a geodatabase (CoBluCarb) and high-resolution maps of soil organic carbon (SOC) distribution by linking National Wetlands Inventory data with the U...
August 17, 2017: Global Change Biology
https://www.readbyqxmd.com/read/28814807/psychological-impact-of-vehicle-exhaust-exposure-insights-from-an-animal-model
#14
Ankita Salvi, Gaurav Patki, Hesong Liu, Samina Salim
Air pollution resulting from exhaust emissions of vehicles has risen in the recent years, reportedly causing major adverse effects on the heart, lungs and the brain. Though respiratory and cardiovascular effects of these emissions are well identified, psychological and neurobiological complications of prolonged exposure to vehicle emissions remain unknown. Pro-oxidants are considered as major constituents of vehicle emissions. This is important considering causal link between oxidative stress and behavioral and cognitive impairments...
August 16, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28814651/n2-fixing-tropical-legume-evolution-a-contributor-to-enhanced-weathering-through-the-cenozoic
#15
REVIEW
Dimitar Z Epihov, Sarah A Batterman, Lars O Hedin, Jonathan R Leake, Lisa M Smith, David J Beerling
Fossil and phylogenetic evidence indicates legume-rich modern tropical forests replaced Late Cretaceous palm-dominated tropical forests across four continents during the early Cenozoic (58-42 Ma). Tropical legume trees can transform ecosystems via their ability to fix dinitrogen (N2) and higher leaf N compared with non-legumes (35-65%), but it is unclear how their evolutionary rise contributed to silicate weathering, the long-term sink for atmospheric carbon dioxide (CO2). Here we hypothesize that the increasing abundance of N2-fixing legumes in tropical forests amplified silicate weathering rates by increased input of fixed nitrogen (N) to terrestrial ecosystems via interrelated mechanisms including increasing microbial respiration and soil acidification, and stimulating forest net primary productivity...
August 16, 2017: Proceedings. Biological Sciences
https://www.readbyqxmd.com/read/28814306/blood-acid-base-status-in-impala-aepyceros-melampus-immobilised-and-maintained-under-total-intravenous-anaesthesia-using-two-different-drug-protocols
#16
Gareth E Zeiler, Leith C R Meyer
BACKGROUND: In mammals, homeostasis and survival are dependent on effective trans-membrane movement of ions and enzyme function, which are labile to extreme acid-base changes, but operate efficiently within a narrow regulated pH range. Research in patients demonstrating a pH shifts outside the narrow regulated range decreased the cardiac output and systemic vascular resistance and altered the oxygen binding to haemoglobin. These cardiopulmonary observations may be applicable to the risks associated with anaesthesia and performance of wildlife ungulates on game farms...
August 16, 2017: BMC Veterinary Research
https://www.readbyqxmd.com/read/28813557/facial-erosive-pustular-dermatosis-after-cosmetic-resurfacing
#17
Julie E Mervak, Stephanie D Gan, Emily H Smith, Frank Wang
Importance: Erosive pustular dermatosis (EPD) is a rare condition that typically affects actinically damaged skin of the scalp. Characterized by sterile pustules, erosions, and crusts, EPD is difficult to treat and heals slowly. The exact cause of EPD is unknown, although trauma is an inciting factor. Objective: To describe 3 women who presented with prolonged facial erosions after cosmetic resurfacing procedures, specifically fully ablative carbon dioxide laser or medium-depth chemical peel...
August 16, 2017: JAMA Dermatology
https://www.readbyqxmd.com/read/28813511/differentiation-of-human-embryonic-stem-cells-into-corneal-epithelial-progenitor-cells-under-defined-conditions
#18
Canwei Zhang, Liqun Du, Kunpeng Pang, Xinyi Wu
The development of cell-based therapies using stem cells represents a significant breakthrough in the treatment of limbal stem cell deficiency (LSCD). The aim of this study was to develop a novel protocol to differentiate human embryonic stem cells (hESCs) into corneal epithelial progenitor cells (CEPCs), with similar features to primary cultured human limbal stem cells (LSCs), using a medium composed of DMEM/F12 and defined keratinocyte serum-free medium (KSFM) (1:1) under different carbon dioxide (CO2) levels in culture...
2017: PloS One
https://www.readbyqxmd.com/read/28813040/enhanced-selectivity-of-methane-production-for-photocatalytic-reduction-by-the-piezoelectric-effect
#19
Kaiqiang Wang, Zhibin Fang, Xueyan Huang, Wenhui Feng, Yaozhu Wang, Bo Wang, Ping Liu
Under simultaneous full arc light and ultrasonic irradiation, photo-generated electrons are brought together by piezoelectric potential, and thus dense electrons induce the reduction of carbon dioxide on the surface of piezoelectric semiconductors, resulting in an improved selectivity of methane production to a greater degree.
August 16, 2017: Chemical Communications: Chem Comm
https://www.readbyqxmd.com/read/28812872/effect-of-mineral-dissolution-precipitation-and-co2-exsolution-on-co2-transport-in-geological-carbon-storage
#20
Ruina Xu, Rong Li, Jin Ma, Di He, Peixue Jiang
Geological carbon sequestration (GCS) in deep saline aquifers is an effective means for storing carbon dioxide to address global climate change. As the time after injection increases, the safety of storage increases as the CO2 transforms from a separate phase to CO2(aq) and HCO3(-) by dissolution and then to carbonates by mineral dissolution. However, subsequent depressurization could lead to dissolved CO2(aq) escaping from the formation water and creating a new separate phase which may reduce the GCS system safety...
August 16, 2017: Accounts of Chemical Research
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