Search Results
Results 451 - 500 of 1048
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Soulat J M - - 1999
BACKGROUND: characterize To the effects of high asbestos exposure during annual periods of insulation. METHOD: 170 ex-workers underwent clinical examination, spirometry, standard chest X-rays and high-resolution computed tomography (HRCT). Asbestos exposure was retrospectively assessed for latency, duration, and intensity. RESULTS: Sixty-six percent of these workers were annually exposed to high ...
Timmins G S - - 1999
This study investigates the respiratory physiology of bioluminescent larvae of Pyrearinus termitilluminans in relation to their tolerance to hypoxia and hyperoxia and to the supply of oxygen for bioluminescence. The partial pressure of oxygen (P(O2)) was measured within the bioluminescent prothorax by in vivo electron paramagnetic resonance (EPR) oximetry following ...
Ponganis PJ - - 1999
To evaluate blood N(2) uptake and the role of the respiratory volume (air sacs/lungs) as a N(2) and O(2) reservoir in deep-diving penguins, diving respiratory volume (Vdr), heart rate (fh), venous P(N)(sum), blood volume (V(b)) and hemoglobin (Hb) concentration were measured in king penguins (Aptenodytes patagonicus) during forced submersions and ...
Hill V M - - 1999
An aqueous glucose-lysine model system (initial pH 10.1) was incubated at 60 degrees C and atmospheric pressure (system A) or 600 MPa (system B) to the same absorbance value at 420 nm. Volatile reaction products were isolated by solvent extraction and analyzed by gas chromatography/mass spectrometry. Thirty-two compounds were identified; ...
Spira A - - 1999
Diving is a high-risk sport. There are approximately between 1 to 3 million recreational scuba divers in the USA (with over a quarter-million learning scuba annually); there are about 1 million in Europe and over 50,000 in the United Kingdom. In this population 3-9 deaths/100,000 occur annually in the US ...
Hanna J M - - 1999
The effects of climate and altitude on casual blood pressure are examined from the perspectives of initial exposure, acclimatization, long-term residence, and birthplace. Hot arid and hot humid climates seem to have little effect on blood pressure, although a slight reduction may be found in some naturally acclimatized groups. Exposure ...
Lenzen M - - 1999
Measurements of the 222Rn and 220Rn concentration in air, the atmospheric pressure, and the air sample temperature were carried out in an abandoned gypsum mine in Walferdange, Luxembourg. The 222Rn concentration shows a negative correlation with the atmospheric pressure and a tentative positive correlation with gravity variations. The results suggest ...
Kumar R - - 1999
OBJECTIVE: A composite Indian herbal preparation-I (CIHP-I) containing ingredients derived from 7 different plants and asphalt was tested for its adaptogenic activity and its mechanism of action was investigated. DESIGN: CIHP-I was tested using the cold-hypoxia-restraint (C-H-R) animal model in which the restrained rats were exposed to 5 degrees C ...
Diarra G M - - 1999
Oxygen consumption of single mosquitoes was measured using a differential pressure transducer (DPT) connected to two small chambers. A mosquito was placed in the experimental chamber (P1) and was separated from NaOH by 4 cm2 of marquisette mesh. The reference chamber (P2) contained the same amount of NaOH and the ...
Neubauer B - - 1999
OBJECTIVES: A hyperbaric environment may influence lactate metabolism due to hyperoxia affecting biochemical pathways. The purpose of our study was to determine the blood lactate levels occurring at high workloads in a sample of professional divers under simulated caisson conditions. The ambient air pressure was equivalent to a diving depth ...
Ozaki T - - 1999
Mechanical forces related to pressure and flow are important for the etiology of atherosclerosis and hypertension. We hypothesized the presence of mechanosensors that were solely sensitive to pure atmospheric pressure in the absence of shear and tensile stresses. A pressure-loading apparatus was set up to examine the effects of atmospheric ...
Massimino D - - 1999
Wheat plants were grown in twin closed growth chambers under normal and reduced atmospheric pressures. For the first 22 days from sowing, the reduced pressure was maintained at 200 hPa, and at 100 hPa for the remaining 27 days until harvest. These pressures were obtained by evacuation of the chamber ...
Bowman C L - - 1999
Accurate knowledge of the internal diameter (id) of micropipet tips is important, because the ability to study many different aspects of biological membranes is a very sensitive function of tip size. The authors examined two methods used to characterize pipet tips: the digital manometric method (DMM) and bubble number method ...
Cockell C - - 1999
Insects have a number of potential roles in closed-loop life support systems. In this study we examined the tolerance of a range of insect orders and life stages to drops in atmospheric pressure using a terrestrial atmosphere. We found that all insects studied could tolerate pressures down to 100 mb. ...
Butler F K FK - - 1999
A myopic shift occurred in a closed-circuit mixed-gas scuba diver using a 1.3 atm abs constant partial pressure of oxygen in a nitrogen-oxygen mix. This change was noticed after approximately 18 days of diving with a mean dive time of 4.04 h each day. The observed myopic shift was due ...
Djurhuus R - - 1999
Saturation diving involves exposure to elevated partial pressure of oxygen (Po2) and high pressure. The present work demonstrated that hyperoxic exposure for up to 72 h had significant effects on human lung fibroblasts. Forty to sixty kPa Po2 had severe acute toxic effects, and 60 kPa O2 reduced plating efficiency ...
Eisenthal A - - 1999
In the present study we show that a brief exposure of human PBMC to hydrostatic pressure (HyP) increased their proliferative response to PHA and anti-CD3 antibody, assessed by DNA synthesis. The effect of HyP was most prominent at 400 atmospheres of HyP followed by 600 and 200 atmospheres. At any ...
Jauchem J R - - 1999
We investigated the thermal distribution and cardiovascular effects produced by sustained exposure of rats to 94 GHz radio-frequency electromagnetic radiation (RFR). Sixteen ketamine-anesthetized Sprague-Dawley rats were exposed individually at a power density of 75 mW/cm2 under far-field conditions in E orientation. Irradiation began when colonic temperature was 37 degrees C ...
Wynne D C DC Department of Chemistry, University of California, Davis, CA 95616, USA, Fax: - - 1999
The tunable dielectric constant ε of supercritical fluoroform is the explanation for pressure-dependent enantioselectivity in a reaction conducted at low pressure. For the cyclopropanation of styrene and methyl phenyldiazoacetate with a dirhodium catalyst, the enantioselectivity was significantly higher at 52 bar than above 80 bar (see plot).
Sada P V - - 1998
We have performed high-resolution spectral observations at mid-infrared wavelengths of CH4 (8.14 micrometers), C2H6 (12.16 micrometers), and C2H2 (13.45 micrometers) on Jupiter. These emission features probe the stratosphere of the planet and provide information on the carbon-based photochemical processes taking place in that region of the atmosphere. The observations were ...
Guy R J - - 1998
BACKGROUND: Primary blast injuries are produced by the blast shock wave. The critical determinant of survival is pulmonary injury, but acute cardiorespiratory responses to blast exposure are not well understood. The aim of this study was to investigate these changes. METHODS: Twenty anesthetized rats were exposed to moderate blast overpressure, ...
Shi Z Y - - 1998
Depth limitations to diving operation with air as the breathing gas are well known: air density, oxygen toxicity, nitrogen narcosis and requirement for decompression. The main objectives of our experiment were to assess the decompression, counterdiffusion and performance aspect of helium-nitrogen-oxygen excursions from nitrox saturation. The experiment was carried out ...
Niemann H B - - 1998
The Galileo probe mass spectrometer determined the composition of the Jovian atmosphere for species with masses between 2 and 150 amu from 0.5 to 21.1 bars. This paper presents the results of analysis of some of the constituents detected: H2, He, Ne, Ar, Kr, Xe, CH4, NH3, H2O, H2S, C2 ...
Boggs D F - - 1998
The air in the respiratory system of diving birds contains a large proportion of the body oxygen stores, but it must be in the lungs for gas exchange with blood to occur. To test the hypothesis that locomotion induces mixing of air sac air with lung air during dives, we ...
Larar A M - - 1998
The feasibility of observing global tropospheric and total ozone (O(3)) fields with a double-etalon Fabry-Perot interferometer (FPI) has been assessed. The FPI provides high spectral resolution and high-throughput capabilities that enable observation in pressure-broadened wings of strong O(3) lines while minimizing the impact of undesirable signal contributions (i.e., from the ...
Ramsey C S - - 1998
A 46-yr-old airline captain with many exposures to altitude chamber, fighter, and airliner flight developed migraine-type headaches after exposure to cabin altitudes above 6,000 feet. He had no prior history of chronic headaches or migraine. Symptoms began within days of starting pravastatin for hypercholesterolemia, but had not occurred during 4 ...
Saito T - - 1998
By using a Mach-Zehnder interferometer, we evaluated photosensitivity in silica-based waveguides deposited by atmospheric pressure vapor deposition. Our results show that photosensitivity with ArF excimer laser irradiation was ten times greater than photosensitivity with KrF excimer laser irradiation. ArF excimer laser irradiation induced a refractive-index change of greater than 2 ...
Shuke N - - 1998
A 19-year-old man with a double-chambered right ventricle (DCRV) and an associated ventricular septal defect was admitted to the hospital for surgical correction. Preoperative study of myocardial perfusion with Tc-99m tetrofosmin SPECT depicted the two chambers of the right ventricle. There was a substantial differential in the radioactive uptake between ...
Meningaud J P - - 1998
OBJECTIVE: The purpose of this study was to investigate the popular belief that the incidence of odontogenic cellulitis is weather-related. Two meteorologic parameters were examined: temperature and atmospheric pressure. STUDY DESIGN: To test the hypothesis being studied, a retrospective cohort study design was used. Medical reports of all patients with ...
Vouyouka A G - - 1998
Many studies over the last decade have indicated that circulatory forces such as shear stress and cyclic strain can influence the endothelial cell (EC) phenotype. However, very little is known about the in vitro effects of pressure on EC. To study this, cultured bovine aortic EC were grown in custom ...
Järvinen P - - 1998
This study attempted to determine whether cold box core makers exposed to triethylamine in foundries experienced headaches or had elevated blood pressure more often than workers without TEA exposure, as proposed by earlier reports. Forty-one core makers in three foundries and 82 referents were interviewed according to a structured questionnaire, ...
Sakairi M - - 1998
We describe the structure of a multi-atmospheric pressure ionisation (multi-API) interface for liquid chromatography-mass spectrometry (LC-MS). This interface includes five modes of atmospheric pressure spray with electron impact ionisation (APEI), atmospheric pressure chemical ionisation (APCI), atmospheric pressure spray ionisation (APSI), electrospray ionisation (ESI) and sonic spray ionisation (SSI). This LC-MS ...
Omae T - - 1998
BACKGROUND AND PURPOSE: There are several reports that have studied the effects of hyperbaric oxygen (HBO) on cerebral blood flow (CBF). However, most of the reports have been of animal experiments, and human studies are few so far. The aim of this study is to clarify the relationship between HBO ...
Nuytten P - - 1998
Manned submersibles and atmospheric diving suits share a number of characteristics, with the most obvious being the rigid hull structure required to maintain a one-atmosphere cabin pressure in the presence of high external pressures. The rigid pressure hull results in a fixed internal volume that allow a simple, mechanical means ...
McEwan C E - - 1998
The genomic GC contents of both nitrogen-fixing and non-fixing members of eight genera of bacteria are investigated. Analysis by t-tests showed that in the two aerobic general investigated (Aquaspirillum and Vibrio) there is a significantly higher GC content in the nitrogen-fixing members of the genus than in those unable to ...
Lillo R S - - 1998
These experiments examined whether increasing the partial pressure of oxygen (PO2), hydrostatic pressure, or both were responsible for the improvement in effectiveness of recompression treatment previously observed in guinea pigs with increasing depths of air. Unanesthetized male guinea pigs (600-700 g) were subjected to 8.6 atm abs (871 kPa) air ...
Taylor W F - - 1998
In vitro studies have shown that mild pressure increases red blood cell (RBC) aggregation. Enhanced RBC aggregation in pathologic states can drive the circulation into stasis. This investigation examined the effects of pressure on RBC aggregation in human volunteers. The hypothesis tested is that RBC aggregation is increased during hyperbaric ...
Balestra C - - 1998
Scuba divers with patent foramen ovale (PFO) may be at risk for paradoxical nitrogen gas emboli when performing maneuvers that cause a rebound blood loading to the right atrium. We measured the rise and fall in intrathoracic pressure (ITP) during various maneuvers in 15 divers. The tests were standard isometric ...
Djurhuus R - - 1998
Saturation diving involves the exposure of humans to elevated partial pressure of oxygen (PO2) and high ambient pressure. The present study is part of a research program that focuses on how such conditions affect basal cellular functions. C3H/10T1/2 Cl 8 mouse embryo fibroblasts were exposed to 20-80 kPa O2 in ...
Kernbach-Wighton G - - 1998
A 24-year-old student died while filling flasks with liquid nitrogen. The arms, legs and back were frozen and the face, ears and neck showed a dark red and livid colour with horizontal lines of demarcation. In the electrocardiogram, the heart showed asystolia followed by wide ventricular complexes. The patient was ...
Reinertsen R E - - 1998
Reduction in ascent speed and an increase in the O2 tension in the inspired air have been used to reduce the risk for decompression sickness. It has previously been reported that decompression speed and O2 partial pressure are linearly related for human decompressions from saturation hyperbaric exposures. The constant of ...
Mennel H D - - 1997
HPNS (high pressure neurological syndrome) is considered to be reversible condition of the nervous system caused by elevated (atmospheric) pressure. Clinical observations and experimental findings gave rise to the belief that this syndrome at least partly functions as a model of a dopamin dependent psychosis. Morphological alterations during or after ...
Tokumaru O - - 1997
Extended and more frequent extravehicular activity (EVA) is planned in NASA's future space programs. The more EVAs are conducted, the higher the incidence of decompression sickness (DCS) that is anticipated. Since Japan is also promoting the Space Station Freedom project with NASA, DCS during EVA will be an inevitable complication. ...
Darbin O - - 1997
High pressure is known as a basic etiological factor underlying central nervous system changes known as the high pressure neurological syndrome (HPNS). In the rat, HPNS includes behavioural disturbances including locomotor and motor hyperactivities (LMA) linked to a striatal dopamine (DA) increase. Recent findings have shown that intracerebroventricular administration of ...
Sato S - - 1997
Experimental middle ear barotrauma was studied morphologically. White guinea pigs were placed in an experimental hyperbaric chamber, and middle ear barotrauma was created by increasing the pressure in the hyperbaric chamber from 1 atmosphere absolute (ATA) to 2 ATA using pure oxygen, maintaining the pressure at 2 ATA for 10 ...
Ferrigno M - - 1997
Electrocardiogram, cardiac output, and blood lactate accumulation were recorded in three elite breath-hold divers diving to 40-55 m in a pressure chamber in thermoneutral (35 degrees C) or cool (25 degrees C) water. In two of the divers, invasive recordings of arterial blood pressure were also obtained during dives to ...
Guerrero F - - 1997
The aim of this study was to investigate the effects of a high ambient pressure of He on vascular contraction induced by noradrenaline and to distinguish the effects of ambient pressure per se from those of increased pressure of inert gas. Rings of thoracic aorta were isolated from male Wistar ...
Abraini J H - - 1997
The psychomotor and cognitive abilities of experienced professional divers participating in training and experimental dives in a hyperbaric chamber were investigated during experiments at high ambient pressure of either air or hydrogen-helium-nitrogen-oxygen mixtures. Decrements in psychomotor ability were not as large as decrements in cognitive ability: manual dexterity was 2-16%, ...
Gomaa M N - - 1997
Ammoniation represents the best technique to detoxify aflatoxin-contaminated grain and it is considered as economically practicable for commercial applications. In the present studyAspergillus parasiticus was used to contaminate yellow corn to produce the final concentration reached 4000 μg/kg corn total aflatoxin. Two procedures of ammoniation (in aqueous ammonia concentrations, 0.25, ...
Kayar S R - - 1997
We analyzed O2 pulse, the total volume of O2 consumed per heart beat, in guinea pigs at pressures from 10 to 60 atmospheres. Animals were placed in a hyperbaric chamber and breathed 2% O2 in either helium (heliox) or hydrogen (hydrox). Oxygen consumption rate (VO2) was measured by gas chromatographic ...
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