869 resultados para Occuational Exposure
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L'activit lectrique du coeur est initie par la gnration spontane de potentiels d'action venant des cellules pacemaker du noeud sinusal (SN). Toute dysfonction au niveau de cette rgion entrane une instabilit lectrique du coeur. La majorit des patients souffrant d'un noeud sinusal dficient ncessitent l'implantation chirurgicale d'un pacemaker lectronique; cependant, les limitations de cette approche incitent la recherche d'une alternative thrapeutique. La base molculaire des courants ioniques jouant un rle crucial dans l'activit du noeud sinusal sont de plus en plus connues. Une composante importante de l'activit des cellules pacemakers semble tre le canal HCN, responsable du courant pacemaker If. Le facteur T-box 3 (Tbx3), un facteur de transcription conserv durant le processus de l'volution, est ncessaire au dveloppement du systme de conduction cardiaque. De prcdentes tudes ont dmontr que dans diffrentes lignes cellulaires le Phorbol 12-myristate 13-acetate (PMA) active l'expression du gne codant Tbx3 via des ractions en cascade partant de la protine kinase C (PKC). L'objectif principal de cette tude est de tester si le PMA peut augmenter la frquence et la synchronisation de l'activit spontane du pacemaker biologique en culture. Plus prcisment, nous avons tudi les effets de l'exposition chronique au PMA sur l'expression du facteur de transcription Tbx3, sur HCN4 et l'activit spontane chez des monocouches de culture de myocytes ventriculaires de rats nonataux (MVRN). Nos rsultats dmontrent que le PMA augmente significativement le facteur transcription de Tbx3 et l'expression ARNm de HCN4, favorisant ainsi l'augmentation du rythme et de la stabilit de l'activit autonome. De plus, une diminution significative de la vitesse de conduction a t releve et est attribue la diminution du couplage intercellulaire. La diminution de la vitesse de conduction pourrait expliquer l'effet ngatif du PMA sur la synchronisation de l'activit autonome du pacemaker biologique. Ces rsultats ont t confirms par un modle mathmatique multicellulaire suggrant que des frquences et rsistances intercellulaires plus leve pourraient induire une activit plus stable et moins synchrone. Cette tude amne de nouvelles connaissances trs importantes destines la production d'un pacemaker biologique efficient et robuste.
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Prevalence of faecal coliform bacteria and the survival of Escherichia coli, Vibrio parahaemolyticus and Salmonella paratyphi were studied in the water and sediment from Vembanadu Lake in the presence and absence of protozoan predators. The density of faecal coliform bacteria ranged between mean MPN value 50809000/100 ml in water and 110,000988,000/1 g in sediment (p <0.01), which was 110 times greater than in overlying water. The laboratory microcosm studies revealed that E. coli, V. parahaemolyticus and S. paratyphi showed significantly higher survival (p <0.05) potential in sediment than in overlying water both in the presence and absence of protozoan predators. The results indicate that Vembanadu Lake sediment constitutes a reservoir of pathogenic bacteria and exhibits potential health hazard from possible resuspension and subsequent ingestion during recreational activities. Therefore, assessment of bacterial concentration in freshwater lake sediments used for contact and non-contact recreation is of considerable significance for the proper assessment of microbial pollution of the overlying water and the management and protection of related health risk at specific recreational sites. In addition, assessment of the bacterial concentration in sediments can be used as a relatively stable indicator of long-term mean bacterial concentration in the water column above.
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Spinel ferrites are commercially important because of their excellent magnetic and catalytic properties. The study by Low Energy Ion Scattering (LEIS) can reveal atomic scale information on the surface. The surface of selected spinel ferrites was investigated by LEIS. It has been found that it is the octahedral sites which are preferentially exposed on the surface of the spinel ferrites. So the probable planes which are exposed on spinel ferrite surfaces are D(110) or B(111). This prediction using LEIS gives scope for tailor-making compounds with catalytically active ions on the surface for various catalytic reactions.
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Resumen tomado de la publicaci??n
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Descriptive study that identified chemical agents (AQ) use and training on risk management and waste disposal techniques in a public Hospital in Valencia. A questionnaire was answered by 48 workers. Information obtained was: personal data, occupational history, AQ used; knowledge of risk management and waste disposal. There were 16 occupations from 12 High Risk areas. Adult emergency was the one with more workers (11 individuals), followed by sterilization and clinical laboratory (7 each) and oncology (5). The remained areas had less than 8.3% workers. The most used anesthetic agents were: Halothane, Enfluorane and Isofluorane 4.17% each and main antineoplastics used were: Doxorubicin 16.67% and Paclitaxel, 5-Fluoracil and Etoposide, 8.33% each. The most mentioned substances were: alcohol (70.8%) and Chlorine (64.6%). None of the answers regarding knowledge of AQ risk management and waste disposal was satisfactory. Statistical associations between training and several variables such as age, time in their job and being or not a professional, resulted non-significant. The correlation between training and the knowledge of AQs management was significant (p < 0.001). Participants showed that their knowledge about chemical occupational risk factors they are exposed to is still insufficient. Therefore, this theme should be included in graduate course curricula. These results provide important data and will serve as a pilot research for the follow up Phase II study that will include clinical aspects and environmental and biological monitoring.
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Resumen tomado de la publicacin
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A study of strial capillary permeability using fluorescent microspheres and immunohistochemistry in mice that do or do not exhibit a reduction in endocochlear potential following a single, intense noise exposure.
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This paper discusses a study done to determine noise levels in operating rooms
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This paper discusses noise exposure to firefighters on the job and whether this contributes to noise induced hearing loss.
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This paper examines a study conducted to evaluate the impact of occupational noise exposure and the role of a hearing conservation program in the occupational setting.
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The focus of this study was to measure the noise exposure that high school basketball referees experience during games.
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This paper examines the effects of noise on high school music teachers.
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This paper discusses the effect of noise exposure on high school aged boys' hearing levels and how to measure the effects.
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This paper examines the noise levels of movies and whether or not movie theater sound levels may be hazardous to audience members.
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This paper describes a study undertaken to study noise levels of rock music.
