Carbon Dioxide (Total 270514 Papers Found)

Information and communications technology (ICT) systems are the core of today’s knowledge based society. Innovations in this area are adapted at tremendous speed and worldwide use of ICT has soared in recent years. However, this unprecedented growth comes at a price: ICT systems are meanwhile responsible for the same amount of CO2 emissions as global air travel. If the growth of ICT systems energy consumption continues at the present pace, it will endanger ambitious plans to reduce CO2 emissio ...
The white rot fungus Phanerochaete chrysosporium degraded DDT [1,1,-bis(4-chlorophenyl)-2,2,2-trichloroethane], 3,4,3',4'-tetrachlorobiphenyl, 2,4,5,2',-4',5'-hexachlorobiphenyl, 2,3,7,8-tetrachlorodibenzo-p-dioxin, lindane (1,2,3,4,5,6-hexachlorocylohexane), and benzo[a]pyrene to carbon dioxide. Model studies, based on the use of DDT, suggest that the ability of Phanerochaete chrysosporium to metabolize these compounds is dependent on the extracellular lignin-degrading enzyme system of this fun ...
The gram-positive bacterium Rhodococcus sp. strain IGTS8 is able to remove sulfur from certain aromatic compounds without breaking carbon-carbon bonds. In particular, sulfur is removed from dibenzothiophene (DBT) to give the final product, 2-hydroxybiphenyl. A genomic library of IGTS8 was constructed in the cosmid vector pLAFR5, but no desulfurization phenotype was imparted to Escherichia coli. Therefore, IGTS8 was mutagenized, and a new strain (UV1) was selected that had lost the ability to des ...
In vivo isotope-fractionation factors were determined for hydrogen and oxygen between plasma water samples and samples of urine, saliva, respiratory water vapor, and carbon dioxide in 20 normal adults. The isotope-fractionation factors ranged from 0.944 to 1.039 for 2H in breath water vapor and for 18O in breath CO2, respectively. When corrected for isotope fractionation, the 2H- and 18O-dilution spaces determined from urine, saliva, respiratory water, and CO2 were within -0.10 +/- 1.09 kg (mean ...
The analysis of air in polar ice cores revealed 30% lower CO2 values during glacial periods than during interglacial periods. At present this is confirmed by results from six different ice cores, two from Greenland and four from Antarctica1–5. In all cores the CO2 change coincides with the change in the isotopic composition of the ice, expressed as either the δ18O or δD ratio; both are indicators for the mean annual surface temperature6. To investigate the relationship between atmospheric CO ...
The physiology and central metabolism of a ppc mutant Escherichia coli were investigated based on the metabolic flux distribution obtained by (13)C-labelling experiments using gas chromatography-mass spectrometry (GC-MS) and 2-dimensional nuclear magnetic resonance (2D NMR) strategies together with enzyme activity assays and intracellular metabolite concentration measurements. Compared to the wild type, its ppc mutant excreted little acetate and produced less carbon dioxide at the expense of a s ...
Biological denitrification of high nitrate-containing wastewater was examined in a sulfur-packed column using a smaller amount of methanol than required stoichiometrically for heterotrophic denitrification. In the absence of methanol, the observed nitrate removal efficiency was only about 40%, and remained at 400 mg NO3 –-N/l, which was due to an alkalinity deficiency of the pH buffer and of CO2 as a carbon source. Complete denitrification was achieved by adding approximately 1.4 g methanol/ ...
A major proportion of bacterial types, common in the gastrointestinal tract of many animals and man, were active in degrading diphenylnitrosamine and dimethylnitrosamine, the former being degraded more rapidly than the latter. At low nitrosamine concentrations (is less than 0.05 micronmol/ml), approximately 55% of added diphenylnitrosamine, 30% of N-nitrosopyrrolidine, and 4% of dimethylnitrosamine were degraded. The route of nitrosamine metabolism by bacteria appears to be different from that p ...
Nine sub-3-h male marathoners performed three 45-min monitored treadmill runs at approximately 75% of VO2max during a 2-wk period. The men were assigned in a random, double-blind fashion following the control run to receive either 350 ml of decaffeinated coffee or 350 ml of decaffeinated coffee with 400 mg of caffeine added 1 h before the second run with crossover to the other beverage for the third run. Venous blood was analyzed for free fatty acids, triglycerides, glucose, and lactic acid befo ...
Eddy covariance nighttime fluxes are uncertain due to potential measurement biases. Many studies report eddy covariance nighttime flux lower than flux from extrapolated chamber measurements, despite corrections for low turbulence. We compared eddy covariance and chamber estimates of ecosystem respiration at the GLEES Ameriflux site over seven growing seasons under high turbulence [summer night mean friction velocity (u*) = 0.7 m s(-1)], during which bark beetles killed or infested 85% of the abo ...
Soot was harvested from five combustion sources: a dodecane flame, marine and bus diesel engines, a wood stove, and an oil furnace. The soots ranged from 20% to 90% carbon by weight and molar C/H ratios from 1 to 7, the latter suggesting a highly condensed aromatic structure. Total surface areas (by nitrogen adsorption using the Brunauer Emmett Teller, BET method) ranged from 1 to 85 m2 g(-1). Comparison of the surface area and meso-pore (pores 2-50 nm) surface area predicted by density function ...
Marine bacteria are the main consumers of freshly produced organic matter. Many enzymatic processes involved in the bacterial digestion of organic compounds were shown to be pH sensitive in previous studies. Due to the continuous rise in atmospheric CO2 concentration, seawater pH is presently decreasing at a rate unprecedented during the last 300 million years but the consequences for microbial physiology, organic matter cycling and marine biogeochemistry are still unresolved. We studied the eff ...
The biotransformation potential of a commercial naphthenic acid (NA) mixture (NA sodium salt; TCI Chemicals) under aerobic conditions was investigated using mixed aerobic cultures developed under various levels and duration of NA exposure. A culture enriched using the commercial NA mixture as the sole carbon source degraded NAs in a range of NA concentrations, regardless of culture age and the presence of a co-substrate; however, only 28.5% of the NA-carbon was detected as CO2 while 44% was util ...
Velopharyngeal sonorous snoring is best treated with uvulopalatopharyngoplasty (UPPP). To reduce surgical risks and minimize the morbidity, a simplified carbon dioxide laser uvulopalatoplasty (LUPP) was performed under local anesthesia. Among a total of 146 patients who had a LUPP performed, there was no significant bleeding or postoperative episodes of asphyxia. The procedure was well tolerated even by those patients with strong vomiting reflexes. The operation time was halved, as was the conva ...
Tropical forests have a mitigating effect on man-made climate change by acting as a carbon sink. For that effect to continue, tropical trees will have to acclimate to rising temperatures, but it is currently unknown whether they have this capacity. We grew seedlings of three tropical tree species over a range of temperature regimes (TGrowth = 25, 30, 35 °C) and measured the temperature response of photosynthetic CO2 uptake. All species showed signs of acclimation: the temperature-response curve ...
Steady-state and dynamic gas exchange responses to ozone visible injury were investigated in an ozone-sensitive poplar clone under field conditions. The results were translated into whole tree water loss and carbon assimilation by comparing trees exposed to ambient ozone and trees treated with the ozone-protectant ethylenediurea (EDU). Steady-state stomatal conductance and photosynthesis linearly decreased with increasing ozone visible injury. Dynamic responses simulated by severing of a leaf re ...
Recently, we have provided evidence that suggests that ethanol (ETOH) acts at the hypothalamic level to cause depressed serum LH levels and delay the onset of puberty in the female rat; however, the mechanism of this action is unknown. Thus, we evaluated the in vitro effects of ETOH on basal and stimulated LHRH and prostaglandin E2 (PGE2) secretion from the median eminence (ME) of prepubertal female rats. Brains were removed, and MEs dissected under a stereomicroscope, rinsed, and preincubated i ...
To evaluate the influence of human activities on ecosystem respiration (CO2) and CH4 fluxes and determine the seasonal and spatial variations, we measured CO2 and CH4 fluxes at four sampling sites (west side of the seawall, WSS; oilfield, OF; Spartina alterniflora coastal marsh, SCM; aquaculture pond, ACP) in the Yellow River estuary from June to December in 2013. Both CO2 and CH4 fluxes showed seasonal and spatial variations in the Yellow River estuary. The average CO2 fluxes from WSS, OF, SCM ...
Responsive assembly of 2D materials is of great interest for a range of applications. In this work, interfacial functionalized carbon nitride (CN) nanofibers were synthesized by hydrolyzing bulk CN in sodium hydroxide solution. The reversible assemble and disassemble behavior of the as-prepared CN nanofibers was investigated by using CO2 as a trigger to form a hydrogel network at first. Compared to the most widespread absorbent materials such as active carbon, graphene and previously reported su ...
[1] We examine the sensitivity of simultaneous simulation of climate, natural C, bomb C, and anthropogenic CO2 uptake to the choice of three different ocean mixing schemes: horizontal/vertical mixing (HV), isopycnal mixing (ISO), and Gent-McWilliams mixing (GM) using an Earth system model of intermediate complexity, Integrated Science Assessment Model-2.5D (ISAM-2.5D). Our modeling results suggest that the HV scheme greatly underestimates the observed values of natural C in the deep ocean, while ...
Production of chemicals directly from carbon dioxide using light energy is an attractive option for a sustainable future. The 1,3-propanediol (1,3-PDO) production directly from carbon dioxide was achieved by engineered Synechococcus elongatus PCC 7942 with a synthetic metabolic pathway. Glycerol dehydratase catalyzing the conversion of glycerol to 3-hydroxypropionaldehyde in a coenzyme B12-dependent manner worked in S. elongatus PCC 7942 without addition of vitamin B12, suggesting that the intri ...
Microbial processes were investigated in the soil of a declining, more eutrophic (Rožmberk West) and a healthy looking, less eutrophic (Rožmberk East) freshwater reed stand. Soil was sampled monthly from June to September 1997. Glucose induced carbon dioxide (CO2) production in oxic and anoxic conditions, methane (CH4) production, nitrification and denitrification activities were measured in laboratory conditions in suspensions prepared from homogenised soil samples. Within a stand the proport ...
Distribution of photoassimilated carbon into major metabolite classes differed between two Antarctic diatom species, Nitzschia curta and a small unicellular Chaetoceros sp.. Time course uptake studies (over 54 h) revealed that 14C allocation appeared to be equilibrated after approximately 8 h at light saturated photosynthesis. During short term dark periods (6 h), polysaccharides as well as low-molecular-weight compounds were catabolised to sustain protein synthesis in the dark, whilst lipid res ...
A formate-requiring auxotroph of Methanobacterium thermoautotrophicum Marburg was isolated after hydroxylamine mutagenesis and bacitracin selection. The requirement for formate is unique and specific; combined pools of other volatile fatty acids, amino acids, vitamins, and nitrogen bases did not substitute for formate. Compared with those of the wild type, cell extracts of the formate auxotroph were deficient in formate dehydrogenase activity, but cells of all of the strains examined catalyzed a ...
Physico-chemical properties of a bioorganic char were modified by pyrolysis in the presence of NaOH, and with subsequent physical activation of carbonaceous species with CO2 a value-added activated carbon was fabricated. Bioorganic char is produced as a co-product during the production of bio-fuel from the pyrolysis of chicken litter. Untreated char contains approximately 37 wt% of C and approximately 43-45 wt% of inorganic minerals containing K, Ca, Fe, P, Cu, Mg, and Si. Carbonization and chem ...
The lattice constants of hydrogenated and deuterated CH4-, CO2-, Xe- (clathrate structure type I) and N2-hydrates (clathrate structure type II) from 10 K up to the stability limit were established in neutron- and synchrotron diffraction experiments and were used to derive the related thermal expansivities. The following results emerge from this analysis: (1) The differences of expansivities of structure type I and II hydrates are fairly small. (2) Despite the larger guest-size of CO2 as compared ...
The sensing properties of carbon nanomaterials are studied and compared in this paper. Graphene oxide and multi-walled carbon nanotube films were used as active layers of chemoresistive gas sensors and characterized at room temperature towards ammonia detection in concentration levels from 100 ppm to 500 ppm in air. We conclude that graphene oxide based sensor has higher response (2.4% to 7.4% in range from 100 ppm to 500 ppm) than the multi-walled carbon nanotubes based one (1.0-2.4%). On the o ...
Two mesoporous ordered carbon materials (MOCs) have been synthesized from silica templates by using sucrose as the carbon precursor. The textural characterization using Ar, N2, and CO2 adsorption combined with neutron diffraction showed that the two samples exhibit a significant microporous volume close to 0.5 cm3/g and an ordered network of mesopores. For both MCM48 and SBA15 templated carbons, adsorption first proceeds with the filling of micropores and then by the filling of mesopores with an ...
Carbon Nanotube (CNT) based gas sensors have a variety of advantages over conventional gas sensors. They are smaller in size, consume less power, have quicker response times, and have great electronic and thermal properties. In addition, they are easy to functionalize and have amazing mechanical properties that allow them to be modified and targeted for a specific gas molecule. This allows them to be highly specific. ...
Muscular exercise is accompanied by evident and perfectly matched cardiovascular and respiratory adjustments to avoid changes in arterial blood gases. The mechanisms responsible for this perfect regulation have not yet been defined. Our previous experimental investigations have shown that a consistent rate of cardiorespiratory reflex responses to exercise is caused by chemosensitive muscular receptors activation. The 2 different types of classical muscular exercise (rhythmic and isometric exerci ...
Selective catalysts that activate small molecules such as hydrocarbons, dioxygen, water, carbon dioxide and dihydrogen are central to new technologies for the use of alternative energy sources. For example, controlled hydrocarbon functionalization can lead to high impact technologies, but such catalysts require a level of molecular control beyond current means. The Center for Catalytic Hydrocarbon Functionalization facilitates collaborations among research groups in catalysis, materials, electro ...
Dusan Kentera was born on April 2nd 1925 in Stip. He finished high school in Belgrade in 1944, graduated from Medical school, University of Belgrade in 1951, and completed his internal medicine residency in 1957. In 1960 he fulfilled the requirements for the teaching position at the University with a thesis "The use of dilution methods in the study of circulation" and defended his PhD thesis "Hemodynamic characteristics of pulmonary hypertension with increased precapillary resistance" in 1964 at ...
Many coral reefs have phase shifted from coral to macroalgal dominance. Ocean acidification (OA) due to elevated CO2 is hypothesised to advantage macroalgae over corals, contributing to these shifts, but the mechanisms affecting coral-macroalgal interactions under OA are unknown. Here, we show that (i) three common macroalgae are more damaging to a common coral when they compete under CO2 concentrations predicted to occur in 2050 and 2100 than under present-day conditions, (ii) that two macroalg ...
Measurement of atmospheric temperature as a function of pressure, T (P ), is key to understanding many atmospheric processes and a prerequisite for retrieving gas mixing ratios and other parameters from solar occultation measurements. This paper gives a brief overview of the solar occultation measurement technique followed by a detailed discussion of the mechanisms that make the measurement sensitive to temperature. Methods for retrieving T (P ) using both broadband transmittance and refraction ...
A complete mineralization of a textile dye widely used in the Chilean textile industry, acid yellow 42 (AY42), was studied. Degradation was carried out in an aqueous solution containing 100mgL(-1) of total organic carbon (TOC) of dye using the advanced solar photoelectro-Fenton (SPEF) process in a lab-scale pilot plant consisting of a filter press cell, which contains a boron doped diamond electrode and an air diffusion cathode (BDD/air-diffusion cell), coupled with a solar photoreactor for trea ...
AIM The aim of this study was to investigate the effect of kisspeptin (KP) on in vitro maturation (IVM) of sheep oocytes aspirated from the ovaries collected from slaughterhouse. MATERIALS AND METHODS Two different experiments were conducted to investigate the effect of KP (5, 10 and 15 µg/ml) alone (experiment 1) or in combination with follicle-stimulating hormone (FSH), luteinizing hormone (LH), and Estradiol (E2) (experiment 2) on IVM of sheep oocytes. Tissue culture medium 199 supplemente ...
The thermal performances of nanocomposite layers formed by Single-walled Carbon Nanotubes (SWCNT) dispersed in 2 different kind of polydimethyl-siloxane (PDMSO) matrices has been investigated by measuring the thermal resistance under conditions similar to the ones used for thermal management in microelectronics. A series of nanocomposite samples with thickness in the range 25 microm(-1) cm have been tested. The nanocomposites were prepared varying the amounts of nanotubes embedded in the matrix ...
The ventilatory responses to pulses or steps in the fraction of CO2 in the insufflated gas stream (FICO2) in awake, unidirectionally ventilated White Leghorn roosters (Gallus domesticus) were studied. Within 0.2-0.5 s of the change in FICO2 at the syrinx, a change in inspiratory or expiratory flow occurred. Increases in FICO2 increased flow and tidal volume (VT), whereas decreases in FICO2 decreased flow and VT. Expiratory duration (TE) was markedly prolonged by decreases in FICO2 and shortened ...
The redox state of the anterior suprasylvian gyrus of cats was measured during electrical stimulation and under hypercapnia on cast immobilized and artificially respirated. The state of the nicotinamide adenine dinucleotide-reduced nicotinamide adenine dinucleotide (NAD/NADH) redox system was monitored by in vivo fluorometry. Hypercapnia was produced by inhalation of 10, 15, and 30% CO2, respectively. Hypercapnic acidosis led to NADH oxidation. The NADH oxidation under 30% CO2 inhalation was sig ...
To illustrate the abilities of several physiologic events to indicate a change in metabolic status, dinitrophenol was used to induce hyperthermia. Ten dogs were divided into two groups, one being mechanically ventilated and the other allowed to breathe spontaneously. End-tidal CO2 (ETCO2) and CO2 production, O2 consumption, mean blood pressure, and rectal temperature were monitored continuously in both groups. Respired volume was measured with a pneumotachograph. An infrared-absorption CO2 analy ...
PURPOSE To evaluate the biocompatibility of five dental cement compositions after directly exposing human gingival fibroblast (HGF) and MC3T3-E1 preosteoblast cells to cement alone and cement applied on commercially pure titanium (cpTi) specimens. MATERIALS AND METHODS Nanostructurally integrated bioceramic (NIB), resin (R), resin-modified glass ionomer (RMGIC), zinc oxide eugenol (ZOE), and zinc phosphate (ZP) compositions were prepared according to the respective manufacturer's instructions. ...
The amount of prostaglandin E2 (PGE2) in the supernatant of human bone marrow cell cultures was measured by radioimmunoassay. Bone marrow cells were obtained from adult patients without hematological malignancies. Marrow mononuclear cells (BMMNC) (0.5 X 10(6)) and marrow nonadherent cells (BMNAC) (0.5 X 10(6)) were cultured at 37 degrees C in 5% CO2 in 0.5 ml RPMI 1640 supplemented with L-glutamine, 10% fetal calf serum and 10 mM Hepes buffer. The levels of PGE2 in the supernatant of BMMNC after ...
METHODS In an attempt to verify non-invasive respiratory monitoring for patients in the early postoperative period, cutaneous O2 and CO2 pressures were monitored in 30 female patients recovering from major gynaecologic surgery under halothane anaesthesia. In a double-blind and randomized fashion, in the recovery room the patients received a single intravenous bolus injection of placebo or 150 mg amiphenazole, a respiratory stimulant. The data were collected and stored in a personal computer, usi ...
A cofacial iron tetraphenyl porphyrin dimer, , bio-inspired by the Ni-Fe containing metalloenzyme, carbon monoxide dehydrogenase (CODH), efficiently and selectively catalyses the electrochemical reduction of CO2 to CO in DMF/10% H2O solution at the electro-generated Fe(0)(por) species with high Faradic efficiency (95%) and TOF (4300 s(-1)) at a moderate overpotential, η = 0.66 V. ...
Fasciolosis is a parasitic helminthes disease caused by Fasciola gigantica. The different larval stage (sporocyst, redia and cercaria) are found in intermediate host snail Lymnaea acuminata. In the present study it has been tried to kill the F. gigantica larvae in vitro/ in vivo condition by the use of ferulic acid there is no mortality of snails. Mortality of larvae in in vivo and in vitro condition were observed at 2h, 4h, 6h and 8h, exposure of ferulic acid. Effect of seasonal variation on ab ...
In this study, the thermal-flow characteristics of atmospheric pressure microwave CO2 plasma were numerically investigated by simulation. The electric and gas flow fields in the reaction chamber with a microwave axial injection torch operated at 2.45 GHz were simulated. The microwave launcher had the standard rectangular waveguide WR340 geometry. The simulation was performed by using the COMSOL Multiphysics plasma model with various mass flow rates of CO2. The electric fields, temperature profil ...
  • Timothy Kohl,
  • Ultrasound in obstetrics & gynecology : the official journal of the International Society of Ultrasound in Obstetrics and Gynecology
  • 2016
Semantic Scholar extracted view of "Impact of partial amniotic carbon dioxide insufflation (PACI) on middle cerebral artery blood flow in mid-gestation human fetuses undergoing fetoscopic surgery for spina bifida aperta." by Timothy Kohl ...
A cloud of carbon dioxide gas, with an estimated volume of 1 km3 was released from Lake Nyos, a volcanic crater lake in Cameroon, Africa, causing 1700 to 2000 human fatalities as well as killing thousands of livestock and wild animals. At the request of the Cameroonian Government, the Office of Foreign Disaster Assistance of the U.S. Department of State sent a multidisciplinary team which included 2 forensic pathologists to assist the Government of Cameroon in investigating this natural disaster ...
DETECTORS most commonly found in gas chromatographic instruments involve the use of thermal conductivity cells. Such cells, particularly those of the thermistor type, decrease in sensitivity with increasing temperature. Since it is necessary sometimes to heat the cell to prevent condensation effects of high-boiling materials leaving the chromato-graphic column, new approaches to this problem were sought. Martin and Smart1 were successful in improving the sensitivity by converting the resolved co ...