Search Results
Results 401 - 450 of 1023
< 4 5 6 7 8 9 10 11 12 13 14 >
Taylor D M - - 2000
STUDY OBJECTIVES: To examine the psychometric and cardiac effects of pseudoephedrine at 1 and 3 atmospheres (atm) of pressure (0 and 66 feet of sea water, respectively), and to make recommendations about the agent's safety in the diving environment. DESIGN: Double-blind, placebo-controlled, crossover study. SETTING: Monoplace hyperbaric chamber of a ...
Taylor D M - - 2000
STUDY OBJECTIVES: To examine the psychometric and cardiac effects of dimenhydrinate at 1 and 3 atmospheres (atm) of pressure (0 and 66 feet of sea water, respectively), and to make recommendations about the drug's safety in the diving environment. DESIGN: Double-blind, placebo-controlled, crossover study SETTING: Monoplace hyperbaric chamber of a ...
Sébert P - - 2000
The hexose part of glycolysis has been studied in the freshwater Chinese crab Eriocheir sinensis exposed to high pressure (101 ATA, i.e. 1000 m depth) at 14 degrees C and in normoxic conditions. Glycolytic fluxes (from glucose, JA and from Glucose 6 Phosphate, JB) have been determined using NADH depletion ...
Hälinen A I - - 2000
The purpose of this study was to characterize the respiratory effects of single and repeated controlled exposures to clean warm humid and cold dry air in a new model of anesthetized, mechanically ventilated guinea pigs, and to compare findings with known effects in humans. Intratracheal air (T(tr)) and retrotracheal tissue ...
Dean J B - - 2000
We developed a hyperbaric chamber for intracellular recording in rat brain stem slices during continuous compression and decompression of the tissue bath with the inert gas helium. Air, rather than helium, was also used as the compression medium in some cases to increase tissue nitrogen levels. An important feature is ...
Dromsky D M - - 2000
We developed a swine model to describe the untreated natural history of severe decompression sickness (DCS) after direct ascent from saturation conditions. In a recompression chamber, neutered male Yorkshire swine were pressurized to a predetermined depth from 50-150 feet of seawater [fsw; 2.52-5.55 atmospheres absolute (ATA)]. After 22 h, they ...
Nightingale J A - - 2000
Epidemiologic evidence suggests a link between morbidity and mortality and levels of particulate matter in the atmosphere. We studied the inflammatory response to inhalation of diesel exhaust particulates (DEP) in normal volunteers. DEP were collected from the exhaust of a stationary diesel engine and were resuspended in an exposure chamber. ...
Ryerson N V - - 2000
This study investigated the effect of pressurized atmosphere on the size and number of voids in dental stones and investments. Control specimens of casts and invested patterns were bench set. Experimental specimens of casts and invested patterns were allowed to set under pressure. The specimens were then sectioned and voids ...
Webb J T - - 2000
INTRODUCTION: Space Shuttle extravehicular activity (EVA) requires decompression from sea level pressure (14.7 psia) to a 4.3 psia (30,300 ft) pressure suit. The transition currently involves altering the shuttle atmosphere to allow shirt-sleeve denitrogenation to occur during a 12 to 36-h staged decompression (SD) at 10.2 psia (9,800 ft) with ...
Yoles E - - 2000
Age is a natural factor that has been found to significantly affect sensitivity to hyperbaric hyperoxia (HBO). Exposure to HBO may lead to damages in the energy metabolism of the brain cells. The aim of this study was to test the effect of HBO on the metabolic, hemodynamic and electrical ...
Belo I - - 2000
The effects of increased air pressure in a culture of the thermophilic microorganism Thermus sp. RQ-1 were investigated. Cell growth dependence on oxygen supply was investigated in a fermenter at atmospheric pressure. Total oxygen depletion from the medium for low values of kLa was observed during the exponential growth phase. ...
Jauchem J R - - 2000
Relatively large thermal gradients may exist during exposure of an animal to microwaves (MWs), particularly at high frequencies. Differences in thermal gradients within the body may lead to noticeable differences in the magnitude of cardiovascular changes resulting from MW exposure. This study compares the thermal distribution and cardiovascular effects of ...
Lacey J P - - 2000
Barotrauma is defined as an injury due to pressure differences between atmospheric and intratympanic pressures. Human beings are well suited to operate within an environment involving small alterations in atmospheric pressure. Man's persistence in operating outside this environment leads to exposure to large pressure differentials with resulting trauma. External, middle, ...
Dohgomori H - - 2000
We evaluated the accuracy of delivery of one type of infusion pump at three nominal flow rates under two environmental pressures (measured in atmospheres absolute, ATA), one of which is used for hyperbaric oxygenation. Overall, we observed significant differences between the two different pressures (1 ATA and 2 ATA). Changes ...
Suarez-Varel M M - - 2000
Spontaneous pneumothorax (SP) is a common respiratory condition that is easily recognized and treated, though the etiology remains largely unknown. Apart from individual factors, it has been suggested that changes in atmospheric pressure may trigger the onset of SP. Our aim was to examine the association between the onset of ...
Parker E C - - 2000
Individual crewmember escape from a disabled U.S. Navy nuclear submarine has never been necessary, but remains an important contingency. Decompression sickness (DCS) is one of the foreseeable risks and a robust mathematical model of DCS incidence has been used to estimate the magnitude of this risk under a variety of ...
Darbin O - - 2000
In mammals high pressure of helium-oxygen (He-O2) breathing mixture leads to the high pressure neurological syndrome (HPNS) which includes a set of behavioural disorders such as locomotor and motor hyperactivity (LMA) and myoclonia. In rats, i.c.v. administrations of competitive NMDA antagonists decrease some of these symptoms suggesting that He-O2 pressure ...
Thomas P S - - 2000
Increasing numbers of patients are receiving hyperbaric oxygen therapy as an intensive care treatment, some of whom have pre-existing airway obstruction. Spirometers are the ideal instruments for measuring airway obstruction, but peak flow meters are useful and versatile devices. The behaviour of both types of device was therefore studied in ...
Dudley R - - 2000
Recent geophysical analyses suggest the presence of a late Paleozoic oxygen pulse beginning in the late Devonian and continuing through to the late Carboniferous. During this period, plant terrestrialization and global carbon deposition resulted in a dramatic increase in atmospheric oxygen levels, ultimately yielding concentrations potentially as high as 35% ...
Saito S - - 2000
A transportable hyperbaric chamber durable for 15 psi of pressure was used to treat a patient suffering from moderate acute mountain sickness at 3700 m above sea level. The symptoms were ameliorated a few minutes after pressurization in the chamber. After a 20-minute stay in the chamber, the patient was ...
Huang E T - - 2000
A novice scuba diver with an implanted ventriculo-peritoneal (VP) shunt inquired about the performance characteristics of his shunt while diving. A literature search revealed no information regarding shunt performance under hyperbaric conditions. The manufacturer could not certify that the shunt would function under pressure. Therefore, four VP shunts were tested ...
Abraini J H - - 1999
High helium pressure of more than 2 MPa produces central neuroexcitatory motor behavior. In rodents, symptoms comprise locomotor and motor activity (LMA), myoclonia, and, at pressure greater than 9-10 MPa, convulsions and tonic-clonic seizures. We studied the behavioral effects of bilateral injection of the glutamate uptake inhibitor L-trans-pyrollidine-2,4-dicarboxylic acid (L-trans-PDC), ...
Sugihara G - - 1999
We use residual-delay maps of observational field data for barometric pressure to demonstrate the structure of latitudinal gradients in nonlinearity in the atmosphere. Nonlinearity is weak and largely lacking in tropical and subtropical sites and increases rapidly into the temperate regions where the time series also appear to be much ...
Enstipp M R - - 1999
Heart rates were recorded from double-crested cormorant chicks during their first ever and subsequent voluntary head submergences and dives, as well as during longer dives made after the chicks were accustomed to diving. Despite variation between chicks, the cardiac response to first ever and subsequent voluntary submergence (head submergences and ...
Peters N T - - 1999
PURPOSE: To evaluate the effect of increased atmospheric pressure on visual acuity in patients who have had radial keratotomy (RK). SETTING: Long Beach Memorial Medical Center, Long Beach, California, USA. METHODS: This controlled clinical study comprised 4 eyes that had RK and 4 control eyes that were age and sex ...
Tetzlaff K - - 1999
The purpose of this study was to evaluate respiratory effects of wet and dry hyperbaric chamber dives to 0.6 MPa ambient pressure in healthy males. There were 19 and 22 subjects who participated in two series of dives with a bottom time of 15 min and decompression times of 28 ...
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 ...
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 ...
< 4 5 6 7 8 9 10 11 12 13 14 >