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Results 351 - 400 of 1052
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Gong Henry H - - 2003
Epidemiologic studies report health effects associated with exposure to ambient particulate matter (PM), but underlying biologic mechanisms remain unclear. We evaluated pulmonary and systemic effects in twelve healthy human adult and twelve asthmatic volunteers exposed once for 2 hours in a whole-body chamber to approximately 200 microg/m3 concentrated ambient particles ...
DeGorordo Antonio - - 2003
Self-Contained Underwater Breathing Apparatus (SCUBA) diving popularity is increasing tremendously, reaching a total of 9 million people in the US during 2001, and 50,000 in the UK in 1985. Over the past 10 years, new advances, equipment improvements, and improved diver education have made SCUBA diving safer and more enjoyable. ...
He Chuanjiu - - 2003
Elevated levels of ethylene occur in enclosed crop production systems and in spaceflight environments, leading to adverse plant growth and sterility. There are engineering advantages in growing plants at hypobaric (reduced atmospheric pressure) conditions in biomass production for extraterrestrial base or spaceflight environments. Objectives of this research were to characterize ...
Theron Michaël - - 2003
The goal of this article was to assess whether a pressure change can constitute a bias of interpretation of pressure effects on pressure-acclimatized fishes. This work consisted first in a study of the recompression effects of mitochondrial extracts from eels pressure-acclimatized; and then in a study of red muscle fibre ...
Meller Renaud - - 2003
HYPOTHESIS: Direct pressure applied on the inner ear cannot induce hearing loss. BACKGROUND: Three possible causes have been described in the literature for inner ear permanent lesions during scuba diving: pressure imbalance between the middle ear and the external ear, appearance of microbubbles in the internal ear, and direct effect ...
Ferretti Guido - - 2003
Several features of potential adaptation to breath-hold diving in diving populations and extreme divers are reviewed. Thermal adaptation consists of an improvement in cold tolerance, as witnessed by a decrease in critical water temperature, and implies an elevation of the shivering threshold associated with a greater body insulation. This is ...
Kim Joon-Youn - - 2003
This study was performed to determine whether there was any relationship between cold exposure and hypertension, and to evaluate risk factors affecting hypertension in cold-exposed workers. In 11 refrigeration industries, 68 male workers working in cold areas more than once per day were selected as the cold-exposed group, and 68 ...
Dean Jay B - - 2003
As ambient pressure increases, hydrostatic compression of the central nervous system, combined with increasing levels of inspired Po2, Pco2, and N2 partial pressure, has deleterious effects on neuronal function, resulting in O2 toxicity, CO2 toxicity, N2 narcosis, and high-pressure nervous syndrome. The cellular mechanisms responsible for each disorder have been ...
Sindosi O A - - 2003
This work aims at defining characteristic air mass types that dominate in the region of Athens, Greece during the cold (November-March) and the warm (May-September) period of the year and also at evaluating the corresponding concentration levels of the main air pollutants. For each air mass type, the mean atmospheric ...
Sicardy B - - 2003
Pluto's tenuous nitrogen atmosphere was first detected by the imprint left on the light curve of a star that was occulted by the planet in 1985 (ref. 1), and studied more extensively during a second occultation event in 1988 (refs 2-6). These events are, however, quite rare and Pluto's atmosphere ...
Fitzpatrick Daniel T - - 2003
INTRODUCTION: There is limited data about the long-term pulmonary effects of nitrox use in divers at shallow depths. This study examined changes in pulmonary function in a cohort of working divers breathing a 46% oxygen enriched mixture while diving at depths less than 12 m. METHODS: A total of 43 ...
Gibbons John A - - 2003
Neurologic and respiratory decompression sickness (DCS) symptoms occurring in the same individual represent complications rarely observed in altitude research. A case is presented of multi-symptom serious DCS resulting from exposure to 12,192 m (40,000 ft). Following 90 min of preoxygenation, the patient was decompressed in a hypobaric chamber from ground ...
Davies Daryl L - - 2003
BACKGROUND: Behavioral and biochemical studies indicate that exposure to 12 times normal atmospheric pressure (12 ATA) of helium-oxygen gas (heliox) is a direct, selective ethanol antagonist. The current study begins to test the hypothesis that ethanol acts by a common mechanism on ligand-gated ion channels by expanding previous hyperbaric investigations ...
Mulkey Daniel K - - 2003
Neuronal sensitivity to pressure, barosensitivity, is illustrated by high-pressure nervous syndrome, which manifests as increased central nervous system excitability when heliox or trimix is breathed at >15 atmospheres absolute (ATA). We have tested the hypothesis that smaller levels of pressure (<or=4 ATA) also increase neuronal excitability. The effect of hyperbaric ...
Vouyouka Angela G - - 2003
High in vitro pressures have been reported to alter smooth muscle cell (SMC) and endothelial cell (EC) phenotype, while endothelial cells (ECs) can influence the proliferation, phenotype, and contractile features of smooth muscle cells (SMC) in coculture systems. However, little is known about the in vitro effects of pressure on ...
Pickard Brian J - - 2003
U-2 pilots are at an increased risk of decompression sickness compared with other aviators in the U.S. Air Force. This is due to the extreme altitudes at which the missions take place. Presented here is a case of decompression sickness that occurred in a U-2 pilot who was wearing a ...
Cheng Tsun-Jen - - 2003
Epidemiologic studies have shown that increased concentrations of ambient particles are associated with cardiovascular morbidity and mortality. However, the exact mechanisms remain unclear. Recent studies have revealed that particulate air pollution exposure is associated with indicators of autonomic function including heart rate, blood pressure, and heart rate variability. However, this ...
Muth C M - - 2003
Elite apnea divers have considerably extended the limits of dive depth and duration but the mechanisms allowing humans to tolerate the compression- and decompression-induced changes in alveolar gas partial pressures are still not fully understood. Therefore we measured arterial blood gas tensions and acid-base-status in two elite apnea divers during ...
van der Werf Siebren Y - - 2003
A new and flexible ray-tracing procedure for calculating astronomical refraction is outlined and applied to the US1976 standard atmosphere. This atmosphere is generalized to allow for a free choice of the temperature and pressure at sea level, and in this form it has been named the modified US1976 (MUSA76) atmosphere. ...
Iwabuchi K - - 2003
In this study, spinach plants were grown under atmospheric and low pressure conditions with constant O2 and CO2 partial pressures, and the effects of low total pressure on gas exchange rates were investigated. CO2 assimilation and transpiration rates of spinach grown under atmospheric pressure increased after short-term exposure to low ...
Bown M J - - 2003
INTRODUCTION: the rate of rupture of abdominal aortic aneurysms (AAAs) has been shown to have a seasonal variation with more ruptures occurring during the winter months. One of the main meterological changes between the seasons is a change in atmospheric pressure. The aim of this study was to investigate whether ...
Pinheiro R - - 2003
AIMS: To investigate the effect of total air pressure raise on cell growth and intracellular beta-galactosidase activity in batch cultures of Kluyveromyces marxianus CBS 7894. METHODS AND RESULTS: A pressurized bioreactor was used for K. marxianus batch cultivation under increased air pressure from 1.2 to 6 bar. Under these conditions ...
Machera K - - 2003
One of the steps during the authorization process of plant protection products (PPP) in the European Union is to evaluate the safety of the operator. For this purpose, information on the probable levels of operator exposure during the proposed uses of the PPP is required. These levels can be estimated ...
Spanarkel Robert - - 2002
The response of lettuce (Lactuca sativa L. cv. Waldmann's Green) to low atmospheric pressure was examined during the initial 5 days of germination and emergence, and also during subsequent growth to vegetative maturity at 30 days. Growth took place inside a 66-l-volume low pressure chamber maintained at 70 kPa, and ...
Lydersen C - - 2002
In this study we used a Doppler ultrasonic device, in combination with a sonographic contrast medium, to test whether free-living bearded seal (Erignathus barbatus) pups have a closed (anatomically or functionally) foramen ovale. A total of 17 examinations were performed on 12 individual pups with a body mass range of ...
Danielides Vasilis - - 2002
The aim of this study was to investigate the influence of weather conditions on the frequency of acute laryngitis in adults. The medical records of 825 patients with a diagnosis of acute laryngitis obtained over a 5-year period were reviewed. Meteorological data reviewed included the daily values of 13 parameters. ...
Balon Norbert - - 2002
Nitrogen-oxygen breathing mixtures, for pressures higher than 0.5 MPa, decrease the release of dopamine in the rat striatum, due to the narcotic potency of nitrogen. In contrast, high pressures of helium-oxygen breathing mixtures of more than 1-2 MPa induce an increase of the striatal dopamine release and an enhancement of ...
Hull Jay G - - 2002
Five studies demonstrated that private self-consciousness is associated with nonconscious, automatic behaviors. In 2 studies, high but not low self-conscious individuals walked more slowly following exposure to an implicit elderly prime. In a 3rd study, high but not low self-conscious individuals showed improved performance following exposure to a subliminal success ...
Dodd I C - - 2002
The role of shoot water status in mediating the decline in leaf elongation rate of nitrogen (N)-deprived barley plants was assessed. Plants were grown at two levels of N supply, with or without the application of pneumatic pressure to the roots. Applying enough pressure (balancing pressure) to keep xylem sap ...
Broekaert J A C - - 2002
Miniaturized microwave, high-frequency, and dc-powered microplasmas are discussed, with emphasis on the state-of-the-art and development trends. Specific atomic emission sources discussed include the microstrip microwave plasma operated in argon and helium at ca 10-30 W and below 1 L min(-1) gas at atmospheric pressure, the capacitively coupled microplasma, operated at ...
Zimmer J L - - 2002
The increased use of UV radiation as a drinking water treatment technology has instigated studies of the repair potential of microorganisms following treatment. This study challenged the repair potential of an optimally grown nonpathogenic laboratory strain of Escherichia coli after UV radiation from low- and medium-pressure lamps. Samples were irradiated ...
Nagashima Hidetoshi - - 2002
Sleep patterns during saturation dives equivalent to a 30-m depth (pressurized condition) and habitation in a confined environment at 1 atm absolute pressure (non-pressurized condition) were studied to determine the effects of environmental pressure. Eight inexperienced divers experienced the pressurized condition of the saturation dives, and nine healthy subjects experienced ...
Muhonen Arja - - 2002
The purpose of the study was to evaluate the effects of irradiation and hyperbaric oxygenation (HBO) on osteoblastic activity of the temporomandibular joint (TMJ) region during mandibular distraction osteogenesis. Unilateral distraction was performed on 19 rabbits, which were divided into five groups. One group served as a control group, while ...
Danielides V - - 2002
This retrospective study aims to search out the influence of temperature, atmospheric pressure and humidity on the frequency of epistaxis. The study includes 701 patients who have suffered from epistaxis and have been treated in the ENT department of the University of Ioannina Hospital, during the years 1995 and 1996. ...
Park Chan Beum - - 2002
The effect of decompression on the structure of Methanococcus jannaschii, an extremely thermophilic deep-sea methanogen, was studied in a novel high-pressure, high-temperature bioreactor. The cell envelope of M. jannaschii appeared to rupture upon rapid decompression (ca. 1 s) from 260 atm of hyperbaric pressure. When decompression from 260 atm was ...
Marković Dubravko - - 2002
This paper describes the treatment of a severe case of acute mountain sickness with a portable hyperbaric chamber. A 37-year old climber was treated for acute high altitude pulmonary oedema, which developed on the North Col of Mount Everest, at an altitude of 7,060 m. The treatment in the portable ...
Kertesz Vilmos - - 2002
Reduction of the oligomers formed from on-line electropolymerization of aniline, the compound N-phenyl-1,4-phenylenediimine, and the thiazine dye thionin was observed in both an atmospheric pressure chemical ionization and an atmospheric pressure photoionization source. The reduction, which alters the mass of these analytes by 2 Da, was shown to occur by ...
Sicko Zdzisław - - 2002
The basic problem in decompression is the limit of maximum tolerable change of pressure after diving. Due to the number of parameters involved in decompression models (bottom time, ambient pressure, exposition profile, content of breathing mixtures, properties of inert gases) the number of possible solutions is theoretically unlimited. Since the ...
Weiner Randy - - 2002
Those individuals interested in diving and flying are often more susceptible to a condition known as barodontalgia: tooth sensitivity or pain caused by a change in pressure. More specifically, the discomfort is caused by a change in ambient pressure, which affects liquids and gases within the body. Diagnosis is based ...
Sakamoto K - - 2002
The effect of pressured environment from 1 to 24 ATA (Atmosphere Absolute) on total power spectrum (TP) of physiological tremor, whose value was the sum of power spectra for frequency range in 0.5-50 Hz, was investigated. The main effects obtained were as follows. (1) In the case of 3 ATA, ...
Dempster William F - - 2002
Atmospheric leakage from a Mars base would create a demand for continuous or periodic replenishment, which would in turn require extraction or mining for oxygen and other gases from local resources and attendant equipment and energy requirements for such operations. It therefore becomes a high priority to minimize leakage. This ...
Coon Joshua J - - 2002
We have designed and constructed an atmospheric pressure laser desorption/chemical ionization (AP-LD/CI) source that utilizes a laser pulse to desorb intact neutral molecules, followed by chemical ionization via reagent ions produced by a corona discharge. This source employs a heated capillary atmospheric pressure inlet coupled to a quadrupole ion trap ...
Neeper Donald A - - 2002
This paper documents a technique for investigating one-dimensional airflow in the vadose zone. Variations in pore gas pressures resulting from barometric cycles were measured at depths as great as 180 m in several gas monitoring wells. The data were transformed to the frequency domain, enabling comparison with closed-form analytic expressions ...
Dubin Marc G - - 2002
OBJECTIVE: To examine the effects of tobacco smoke exposure on eustachian tube (ET) function. STUDY DESIGN: ET pressures of Sprague Dawley Rats (n = 16) were measured after 1, 7, and 15 exposures and in control animals. Passive opening pressure, passive closing pressure, active clearance of positive pressure, and active ...
de Diego J I - - 2002
To assess the possible influence of atmospheric factors on the incidence of Bell's palsy, a retrospective case review of patients seen between 1 January 1992 and 30 June 1996, was designed. The population included all Bell's palsy patients in whom the exact date of onset of paralysis (day, month, year) ...
Lemaître F - - 2002
Long term effects on respiratory function have been found in air divers and have indicated the development of small-airway disease. These effects have been attributed to oxygen toxicity or to venous gas micro emboli (VGM). The airway obstructions observed in air divers raise fundamental questions about whether these alterations exist ...
Dillard T A - - 2001
Millions of people engage in occupational or leisure activities at high altitude or at variable depths below sea level. This article presents an overview of the utility of pulmonary function testing in evaluating complications and other consequences of exposure to high and low pressure environments. The authors review recent literature ...
Boggs D F - - 2001
Air-sac pressures have been reported to oscillate with wing beat in flying magpies and with foot paddling in diving ducks. We sought to determine the impact on air-sac pressure of wing beats during swimming and of the step cycle during walking in little penguins (Eudyptula minor). Fluctuations averaged 0.16+/-0.06 kPa ...
McGregor G R - - 2001
Winter ischaemic heart disease (IHD) mortality events (ME) were identified in order to establish their degree of meteorological sensitivity. Sensitivity was evaluated using regression of surface meteorological and large-scale atmospheric circulation variables on daily mortality for each mortality event. Critical meteorological variables affecting IHD mortality appear to be local surface ...
Buxton N - - 2001
OBJECT: The purpose of this study was to evaluate the relationship between atmospheric pressure and subarachnoid hemorrhage (SAH) in a region in the English Midlands. METHODS: All patients with angiographically proven SAH for the calendar year 1998 were analyzed. A geographical allocation was made based on the patients' origin within ...
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