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At least 937 records · Page 52Linked to original sources
PubMedDate not supplied

Thunderstorm-associated asthma or shortness of breath epidemic: a Canadian case report.

Thunderstorm-associated asthma epidemics have been documented in the literature, but no Canadian experience has been reported. On July 31, 2000, a thunderstorm-associated epidemic of asthma or shortness of breath occurred in Calgary, Alberta. The Calgary Health Region investigated the event using diagnostic data from emergency departments, an urgent care medical clinic and patient interviews, in addition to bioaerosol counts, pollutant data and weather data reflecting atmospheric conditions at that time. On July 31, 2000 and August 1, 2000, 157 people sought care for asthma symptoms. The expected number of people to seek care for such symptoms in a 48 h period in Calgary is 17. Individuals with a personal or family history of asthma, allergies or hay fever who were not taking regular medication for these conditions and who were outdoors before the storm appeared to have been preferentially affected. A stagnant air mass the day before the thunderstorm may have resulted in declining bioaerosol concentrations, and the possible accumulation of spore and pollen reservoirs within mould and plant structures. The elevated bioaerosol concentrations observed on the day of the thunderstorm may be attributed to the sudden onset of high winds during the thunderstorm, which triggered a sudden release of spores and pollens into the atmosphere, which was probably responsible for the epidemic. Several pollutant levels slightly increased on the day of the storm and possibly also played a role in symptom development. It is unclear whether an atmospheric pressure drop contributed to the release of spores and pollens.

Adolescent↗
PubMed2000

The role of environmental factors in asthma.

Although the everyday experience of asthmatic patients provides ample anecdotal evidence that environmental exposures provoke bronchospasm, it has proved more difficult to assess the impact of air quality on the timing of asthma attacks and the prevalence of asthma in populations. Spectacular 'asthma epidemic days' are sometimes attributable to exceptional outdoor aero-allergen exposures. By comparison, effects of inorganic particles and gaseous pollutants in outdoor air on the incidence of asthma attacks are subtle and poorly quantified. Environmental tobacco smoke and mould growth are the indoor factors most consistently associated with respiratory morbidity, but their roles in initiating allergic asthma remain uncertain. Evidence relating asthma risk to fumes from gas cooking, and to allergens from dust mites and household pets remains confused and controversial. It is unlikely that trends in either outdoor or indoor air pollution have contributed substantially to the rise in prevalence of asthma and allergic disease in recent decades.

Adolescent↗
PubMedDate not supplied

Shuttles of artificial electron donors for photosystem I across the thylakoid membrane.

NADP+ reduction in isolated chloroplasts of spinach by photosystem I at the expense of various artificial donor systems is not inhibited by the plastoquinome antagonist dibromothymoquinone. The coupled ATP formation in such photoreductions is attributed to an artificial energy conserving site, i. e. a proton liberation during oxidation of the donor at the inner surface of the thylakoid membrane. Some donor systems for photosystem I are stimulated by uncouplers whereas others are not. The stimulation shows no correlation to the efficiency of the coupled photophosphorylation. Instead a correlation of the stimulation by uncouplers to the presence of an acidic OH-group in the donor molecule is seen. The uncoupler effect is therefore not explained by a release of electron transport control by the high energy state but rather by a pH-dependent distribution of the donor compound across the membrane. This is supported by the properties of donor systems in sonicated chloroplast particles with external oxidation sites of photosystem I.

Adenosine Triphosphate↗
PubMed2006

Atmospheric flash injuries in roe deer (Capreolus capreolus).

The pathological and histopathological examination of two female roe deer found dead after a severe thunderstorm is described. One of the two roe deer was killed by a direct hit of atmospheric flash, while the other animal, lying 1.5 m from the first one, died as a consequence of ground current strike. The major part of the coat and skin of the animal that was killed by a direct hit was covered with scorched streaks. The trachea and bronchi of both animals contained a considerable amount of aspirated light-red foam. Necropsy revealed diffuse haemorrhages over the epicardium of the right atrium with a diameter of 1 millimetre. The liver and the kidney exhibited severe congestion.

Animals↗
PubMed1998

Corona chemistry in Titan.

The atmosphere of Titan is constantly bombarded by galactic cosmic rays and Saturnian magnetospheric electrons causing the formation of free electrons and primary ions, which are then stabilized by ion cluster formation and charging of aerosols. These charged particles accumulate in drops in cloud regions of the troposphere. Their abundance can substantially increase by friction, fragmentation or collisions during convective activity. Charge separation occurs with help of convection and gravitational settling leading to development of electric fields within the cloud and between the cloud and the ground. Neutralization of these charged particles leads to corona discharges which are characterized by low current densities. We have therefore, experimentally studied the corona discharge of a simulated Titan's atmosphere (10% methane and 2% argon in nitrogen) at 500 Torr and 298 K by GC-FTIR-MS techniques. The main products have been identified as hydrocarbons (ethane, ethyne, ethene, propane, propene+propyne, cyclopropane, butane, 2-methylpropane, 2-methylpropene, n-butane, 2-butene, 2,2-dimethylpropane, 2-methylbutane, 2-methylbutene, n-pentane, 2,2-dimethylbutane, 2-methylpentane, 3-methylpentane, n-hexane, 2,2-dimethylhexane, 2,2-dimethylpentane, 2,2,3-trimethylbutane, 2,3-dimethylpentane and n-heptane), nitriles (hydrogen cyanide, cyanogen, ethanenitrile, propanenitrile, 2-methylpropanenitrile and butanenitrile) and a highly branched hydrocarbon deposit. We present the trends of hydrocarbons and nitriles formation as a function of discharge time in an ample interval and have derived their initial yields of formation. The results clearly demonstrate that a complex organic chemistry can be initiated by corona processes in the lower atmosphere. Although photochemistry and charged particle chemistry occurring in the stratosphere can account for many of the observed hydrocarbon species in Titan, the predicted abundance of ethene is too low by a factor of 10 to 40. While some ethene will be produced by charged-particle chemistry, the production of ethene by corona processes and its subsequent diffusion into the stratosphere appears to be an adequate source. Because little UV penetrates to the lower atmosphere to destroy the molecules formed there, the corona-produced species may be long-lived and contribute significantly to the composition of the lower atmosphere and surface.

Aerosols↗
PubMedDate not supplied

Electrocution in Western Australia, 1976-1990.

OBJECTIVE: To describe the epidemiology of electrical fatalities in Western Australia between 1976 and 1990. DATA SOURCES: Data for the study were gathered from hospital records, autopsy reports and findings from State Energy Commission and coronal investigations. DATA EXTRACTION: Information that was abstracted included age, sex, occupation, voltage, history of incident and autopsy findings. DATA SYNTHESIS: There were 104 victims. Death occurred most frequently in young men exposed to low voltage current during summer, and nearly half the fatalities occurred in the workplace. Water was present in up to 52% of fatalities. Without exception, all victims developed a lethal arrhythmia at the time of exposure to the electric shock, which usually resulted in death at the scene. CONCLUSION: When a victim is exposed to a fatal electric shock, the lethal arrhythmia occurs at the time of electrocution and is just as likely to occur at home as in the workplace. Electrical fatalities can be prevented largely by the use of residual current devices.

Accidents, Home↗
PubMed2000

Next-generation pulse oximetry. Focusing on Masimo's signal extraction technology.

Pulse oximeters are used to determine trends in patients' blood oxygen saturation and to warn of dangerous saturation levels. But conventional pulse oximetry has some inherent limitations. For example, it has difficulty monitoring patients who are moving or who have poor perfusion; it is also subject to interference from certain visible and infrared light sources. Over the past several years, a number of companies have developed advanced signal-processing techniques that allow pulse oximeters to overcome many of these limitations. We refer to such new technologies as next-generation pulse oximetry. In this Evaluation, we focus on the first next-generation technology to have reached the market: Masimo Corporation's Signal Extraction Technology (SET). We designed our study of Masimo SET to address the main question that needs to be asked of any next-generation technology: How well does it compare to conventional pulse oximetry? Specifically, how well does it perform when a patient is moving or being moved, when a patient is poorly perfused, or when certain types of light strike the sensor while it is attached to or detached from the patient? We also examined one type of sensor used with this product, comparing it to conventional tape-on sensors for comfort and durability. Several other next-generation pulse-oximeter products have become available since we began this study. We are currently evaluating these products and will publish our findings in the near future. A list of the products, including a brief description of each, is included in this article. Pulse oximeters are used to determine trends in patients' blood oxygen saturation and to warn against dangerous saturation levels. These monitors are often vital in helping to ensure patient safety, especially for critically ill patients, pediatric patients, and neonates. But conventional pulse oximetry has some inherent limitations--most significantly, it has difficulty monitoring patients who are moving or who have poor perfusion. Although gradual improvements have been made to the technology, only recently has it advanced to the point where it has really begun to overcome these limitations. A number of manufacturers have developed advanced signal-processing algorithms that allow pulse oximeters to "read through" motion and conditions of poor perfusion. The first of these "next-generation" pulse-oximeter technologies that reached the market was Masimo Corporation's Signal Extraction Technology (SET). We tested that product in this Evaluation. In this Overview, we'll tell you about conventional pulse oximetry and its shortfalls, next-generation technology and how it's designed to improve on the old methods, and how we approached our Evaluation of Masimo SET.

Adult↗
PubMed1975

Electric shock.

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Accidents, Home↗