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Casselbrant A - - 2003
BACKGROUND: The present study explores some aspects of the triggering of the acid-induced oesophago-salivary reflex. In addition to hydrogen ions, there are two acid-dependent molecules with messenger potential in the oesophageal lumen: CO2 and NO. The aim of this study was to clarify whether oesophageal NO and CO2 participate in ...
Conyers Simon T - - 2003
The results of a laboratory investigation into the effects of modified atmospheres (MA) on the eggs of mite pests of grain and cheese are presented. Four species of astigmatid mite were tested; Acarus farris (Oudemans). A. siro L., Lepidoglyphus destructor (Schrank) and Tyrophagus longior (Gervais). All are found in many ...
Carcaillet C - - 2002
Fire regimes have changed during the Holocene due to changes in climate, vegetation, and in human practices. Here, we hypothesise that changes in fire regime may have affected the global CO2 concentration in the atmosphere through the Holocene. Our data are based on quantitative reconstructions of biomass burning deduced from ...
Sun Xing-Guo - - 2002
When evaluating dyspnea in patients with heart or lung disease it is useful to measure the quantity of ventilation needed to eliminate metabolically produced CO2 (i.e., the ventilatory efficiency). Mathematically, the relationship between ventilation (VE) and CO2 output is determined by the arterial CO2 pressure and the physiologic dead space-tidal ...
Ruan Benfang - - 2002
Yeast produce traces of aberrant sterols by minor alternative pathways, which can become significant when normal metabolism is blocked by inhibitors or mutations. We studied sterols generated in the absence of the delta(8)-delta(7) isomerase (Erg2p) or delta(5) desaturase (Erg3p) by incubating three mutant strains of Saccharomyces cerevisiae with 5 alpha-cholest-8-en-3beta-ol, ...
Shoemaker J K - - 2002
We tested the hypothesis that integrated sympathetic and cardiovascular reflexes are modulated by systemic CO2 differently in hypoxia than in hyperoxia (n = 7). Subjects performed a CO2 rebreathe protocol that equilibrates CO2 partial pressures between arterial and venous blood and that elevates end tidal CO2 (PET(CO2)) from approximately 40 ...
DeLucia Evan H - - 2002
We compared radiation-use efficiency of growth (epsilon;), defined as rate of biomass accumulation per unit of absorbed photosynthetically active radiation, of forest plots exposed to ambient (approximately 360 micro l l-1) or elevated (approximately 560 micro l l-1) atmospheric CO2 concentration ([CO2]). Large plots (30-m diameter) in a loblolly pine ...
Turner Duncan L - - 2002
Repeated hypercapnic exercise augmented the ventilatory response to subsequent trials of exercise alone in running goats and in humans performing arm exercise, suggesting a form of associative conditioning or 'long-term modulation' had taken place. These studies did not include 'control' single stimulus conditioning paradigms. This study demonstrated that ten repeated ...
Brown Sandra - - 2002
The global carbon cycle is significantly influenced by changes in the use and management of forests and agriculture. Humans have the potential through changes in land use and management to alter the magnitude of forest-carbon stocks and the direction of forest-carbon fluxes. However, controversy over the use of biological means ...
Miller Martin F - - 2002
Nearly all chemical processes fractionate 17O and 18O in a mass-dependent way relative to 16O, a major exception being the formation of ozone from diatomic oxygen in the presence of UV radiation or electrical discharge. Investigation of oxygen three-isotope behavior during thermal decomposition of naturally occurring carbonates of calcium and ...
Perry Steve F - - 2002
The gill is both a site of gas transfer and an important location of chemoreception or gas sensing in fish. While often considered separately, these two processes are clearly intricately related because the gases that are transferred between the ventilatory water and blood at the gill are simultaneously sensed by ...
Stenqvist Ola - - 2002
BACKGROUND: Clinically applicable methods for measuring FRC are currently lacking. This study presents a new method for FRC monitoring based on quantification of metabolic gas fluxes of O2 and CO2 during a short apnea. METHODS: Base line exchange of oxygen and carbon dioxide was measured with indirect calorimetry. End-tidal ( ...
Affek Hagit P - - 2002
Isoprene (2-methyl-1,3-butadiene) protection against effects of singlet oxygen was investigated in Myrtus communis and Rhamnus alaternus. In M. communis, singlet oxygen produced in the leaves by Rose Bengal (RB) led to a 65% decrease in net assimilation rates within 3 h, whereas isoprene emission rates showed either a 30% decrease ...
Gos T - - 2002
Carbon dioxide euthanasia is an established method for the termination of small laboratory animals. It has also been employed by the authors in neurobiological research on the post-mortem glutamate concentration in the structures of rat brains. The following investigations were aimed at optimizing the termination procedure based on the CO2 ...
Chan Theodore C - - 2002
We performed a randomized, cross-over controlled trial to assess the effect of Oleoresin capsicum (OC) spray inhalation on respiratory function by itself and combined with restraint. Thirty-five subjects were exposed to OC or placebo spray, followed by 10 min of sitting or prone maximal restraint position (PMRP). Spirometry, oximetry, and ...
Arena Ross - - 2002
BACKGROUND: Several ventilatory expired gas measures obtained during exercise testing demonstrate prognostic value in the heart failure (HF) population. Comparison of prognostic efficacy between pertinent measures is sparse. METHODS: The ability of various expressions of peak oxygen consumption (VO2), the relationship between minute ventilation (VE) and carbon dioxide production (VCO2), ...
Lai Yih-Loong - - 2002
Antioxidants attenuate hyperpnea-induced airway constriction. It was hypothesized that this type of airway constriction is closely related to reactive oxygen species (ROS). However, there is no direct evidence of an increase in ROS during or right after the course of hyperpnea. To detect ROS production induced by hyperpnea, forty one ...
Clair T A - - 2002
Temperate forests can contain large numbers of wetlands located in areas of low relief and poor drainage. These wetlands can make a large contribution to the dissolved organic carbon (DOC) load of streams and rivers draining the forests, as well as the exchange of methane (CH4) and carbon dioxide (CO2) ...
Nieuwenhuijs D - - 2001
We tested the effect of tramadol on ventilatory control by quantifying its effect on the steady-state ventilatory carbon dioxide response and by locating its site of respiratory action within the ventilatory control system. We imposed square-wave changes in end-tidal carbon dioxide (approximately 1 kPa; end-tidal oxygen concentration kept constant at ...
Zha T - - 2001
We determined effects of long-term elevation of carbon dioxide concentration ([CO2]) and temperature on growth, respiration and carbohydrate concentration in needles of field-grown Scots pine (Pinus sylvestris L.) trees during the needle expansion period. Sixteen 20-year-old Scots pine trees were individually enclosed in closed-top, environmentally controlled chambers for 4 years ...
Kemme M J - - 2001
During studies on warfarin, heparin and various anticoagulants with novel mechanisms of action, the activated partial thromboplastin time (aPTT) and the (apparent) international normalized ratio (INR) from a bedside monitor (Coagucheck Plus(R)) were compared with laboratory assay results. Data were compared using the Bland and Altman method of comparison where ...
Beaufort L - - 2001
Late Pleistocene changes in oceanic primary productivity along the equator in the Indian and Pacific oceans are revealed by quantitative changes in nanoplankton communities preserved in nine deep-sea cores. We show that variations in equatorial productivity are primarily caused by glacial-interglacial variability and by precession-controlled changes in the east-west thermocline ...
Webster A B - - 2001
Observations of the behavioral reactions of laying hens and broilers to different gas stunning atmospheres were made. Sixty Hy-Line W-36 hens and 60 market-weight commercial broilers were placed individually into a plexiglass gas stunning unit and exposed to one of six gas atmospheres: air, concentrations of 30, 45, or 60% ...
Zhang Q - - 2001
Joint Implementation under the Climate Change Convention and Clean Development Mechanism of the Kyoto Protocol require a scientific understanding of current carbon stocks, fluxes, and sequestration potential, especially in tropical ecosystems where there are large carbon reservoirs, significant carbon emissions, and large land areas available for reforestation. Central Africa contains ...
Bavis R W - - 2001
To test the hypothesis that the adult ventilatory response to CO2 can be modified by exposure to CO2 during development, we exposed Japanese quail (Coturnix japonica) from two populations to 2% CO2 throughout embryonic development. The ventilatory response to 6% CO2 was subsequently measured in control and CO2-exposed quail following ...
Steinacker J M - - 2001
The slope of the expired alveolar partial pressure of carbon dioxide profile increases during exercise. Its relationship to metabolic rate, however, remains to be determined at high exercise intensities. We therefore determined the slope of alveolar partial pressures of carbon dioxide and oxygen (PACO2, PAO2, respectively) during incremental cycle ergometer ...
Rodman J R - - 2001
We assessed the time course of changes in eupneic arterial PCO(2) (Pa(CO(2))) and the ventilatory response to hyperoxic rebreathing after removal of the carotid bodies (CBX) in awake female dogs. Elimination of the ventilatory response to bolus intravenous injections of NaCN was used to confirm CBX status on each day ...
Tanner L H - - 2001
The Triassic/Jurassic boundary, 208 million years ago, is associated with widespread extinctions in both the marine and terrestrial biota. The cause of these extinctions has been widely attributed to the eruption of flood basalts of the Central Atlantic Magmatic Province. This volcanic event is thought to have released significant amounts ...
Hernández P A - - 2001
Magmatic carbon dioxide (CO2) degassing has been documented before the 31 March 2000 eruption of Usu volcano, Hokkaido, Japan. Six months before the eruption, an increase in CO2 flux was detected on the summit caldera, from 120 (September 1998) to 340 metric tons per day (September 1999), followed by a ...
Yamaura K - - 2001
BACKGROUND: Phosphodiesterase (PDE) III inhibitors have both an inotropic and a peripheral vasodilatory effect, and also inhibit the activation of macrophages. Thus a newly developed PDE III inhibitor, olprinone, could modify gastric intramucosal pH (pHi), systemic oxygen consumption, and systemic inflammatory responses in patients undergoing cardiac surgery with cardiopulmonary bypass ...
Moe W M - - 2001
The literature reports conflicting observations regarding the need for nutrient addition to biofilters treating contaminated gases. Such conflicts are often based on quasi-steady-state performance data collected on biofilters operated under continuous loading conditions. In the studies described herein, the impact of nitrogen limitations on two toluene-fed biofilters was assessed over ...
Fatemian M - - 2001
The ventilatory sensitivity to CO2, in hyperoxia, is increased after an 8-h exposure to hypoxia. The purpose of the present study was to determine whether this increase arises through an increase in peripheral or central chemosensitivity. Ten healthy volunteers each underwent 8-h exposures to 1) isocapnic hypoxia, with end-tidal PO2 ...
Wang T - - 2001
Many ectothermic vertebrates ingest very large meals at infrequent intervals. The digestive processes associated with these meals, often coupled with an extensive hypertrophy of the gastrointestinal organs, are energetically expensive and metabolic rate, therefore, increases substantially after feeding (specific dynamic action, SDA). Here, we review the cardio-respiratory consequences of SDA ...
Lee S M - - 2001
BACKGROUND: In a previous study from our laboratory, we observed carbon dioxide (CO2) accumulation in the helmet of the NASA Launch and Entry Suit (LES) during a simulated emergency egress from the Space Shuttle. Of 12 subjects, 8 were unable to complete the egress simulation with a G-suit inflation pressure ...
Al-Delaimy W K - - 2001
OBJECTIVES: To examine the effect of breathing 3% CO2 on exercise-induced asthma (EIA), as a raised airway CO2 level is suggested to mediate the effects of Buteyko breathing training (BBT). DESIGN: Double-blind crossover study, using a standard laboratory-based exercise challenge, with EIA defined as a fall of 15% or greater ...
Miglietta F - - 2001
The Bog Ecosystem Research Initiative (BERI) project was initiated to investigate, at five climatically different sites across Europe, the effects of elevated CO2 and N deposition on the net exchange of CO2 and CH4 between bogs and the atmosphere, and to study the effects of elevated CO2 and N deposition ...
Robbins P A - - 2001
The purpose of this article is to set out the hypothesis that arterial PO2 may play a significant role in the regulation of breathing at sea level. The following points are made: 1) Although CO2 is clearly the dominant feedback signal in the acute setting, there is evidence, particularly clinical ...
Chappell M A - - 2000
Ventilatory accommodation of changing metabolic rates is a relatively little-studied aspect of the discontinuous gas exchange cycles (DGCs) that occur in a wide variety of terrestrial arthropods. We used correlation analysis of resting metabolic rate (RMR, measured as the rate of CO(2) emission; V(CO2)) and several components of the DGC ...
Saucier L - - 2000
The shelf life of ground chicken and turkey meat packaged under a modified atmosphere containing O2 and a high level of CO2 (62% CO2, 8% O2, and 30% N2; gas-1), or a gas mixture without O2 (20% CO2 and 80% N2; gas-2) was evaluated for 20 d at 1 C. ...
Haouzi P - - 2000
In order to describe the factors which, during hyperoxic exercise, can counteract the chemoreceptor-mediated inhibition of ventilation by O2, minute ventilation (VE) and the pulmonary gas exchange were studied breath-by-breath in four dogs running on a treadmill (5 km x h(-1)) for 10 min during and following exposure to O2 ...
Benallal H - - 2000
The aim of this paper was to analyse the difference between end-tidal carbon dioxide tension (PETCO2) and arterial carbon dioxide tension (PaCO2) at rest and during exercise using a homogeneous lung model that simulates the cyclic feature of breathing. The model was a catenary two-compartment model that generated five non-linear ...
Haouzi P - - 2000
The study of a patient with an Arnold Chiari malformation gave us the opportunity to test the hypothesis that the motor cortex contributes significantly to respiratory control during muscular exercise through the corticospinal pathway. The patient was a 25 years old woman who exhibited a severe impairment of the 'automatic' ...
Heman-Ackah Y D - - 2000
Sudden infant death syndrome is the leading cause of death in infants in the United States. The laryngeal chemoreflex (LCR) is thought to contribute to its pathogenesis. In adult animals, increasing levels of intralaryngeal CO2 result in a decrease in ventilatory activity. Intravenous acetazolamide (AZ) abolishes this response. The purpose ...
Sun X G - - 2000
BACKGROUND AND STUDY OBJECTIVE: Theoretically, cardiac output (CO) calculated by the Fick principle should be the same using O(2) (CO[O2]) or CO2 (CO[CO2]) as the test gas. However, agreement depends on the accuracy of gas exchange and blood gas measurements and the validity of the equations to convert measured variables ...
Carswell F E - - 2000
Carbon assimilation by Cedrela odorata L. (Meliaceae) seedlings was investigated in ambient and elevated CO2 concentrations ([CO2]) for 119 days, using small fumigation chambers. A solution containing macro- and micronutrients was supplied at two rates. The 5% rate (high rate) was designed to avoid nutrient limitation and allow a maximum ...
van der Meer M T - - 2000
Inferences about the evidence of life recorded in organic compounds within the Earth's ancient rocks have depended on 13C contents low enough to be characteristic of biological debris produced by the well-known CO2 fixation pathway, the Calvin cycle. 'Atypically' high values have been attributed to isotopic alteration of sedimentary organic ...
Secor S M - - 2000
To investigate the potential limiting steps of peak metabolic rates, we examined gas exchange rates ( vdot (O2), vdot (CO2)), respiratory exchange ratio (RER), breathing frequency, tidal volume, minute ventilation volume (V.e) as well as the heart rate, systemic blood flow and stroke volume of Burmese pythons (Python molurus) while ...
Forster H V - - 2000
Pulmonary ventilation (VE) increases during exercise to meet the demands of increased oxygen consumption (VO2) and CO2 production. Despite numerous studies over the past century, the mechanism mediating exercise hyperpnea remains controversial. Progress has been limited primarily by the incomplete understanding of the complex basic ventilatory control system and by ...
Henderson D R - - 2000
Increased respiratory dead space causes a serotonin (5-HT) dependent augmentation of the exercise ventilatory response known as short term modulation (STM). Contrary to predictions, 5-HT reuptake inhibition with fluoxetine failed to enhance, and even impaired STM with large dead space volumes (0.4-0.6 L). In this study, we tested the hypotheses ...
Carter R - - 2000
The slow response characteristics of the combined transcutaneous electrode have been viewed as a major disadvantage when compared with other types of non-invasive assessment of gas exchange during exercise testing. We have previously shown that by using the highest recommended temperature of 45 degrees C to reduce response times, and ...
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