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Pesquisa : G01.374.618 [Categoria DeCS]
Referências encontradas : 3179 [refinar]
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  1 / 3179 MEDLINE  
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PMID:28002504
Autor:Moreno T; Querol X; Martins V; Minguillón MC; Reche C; Ku LH; Eun HR; Ahn KH; Capdevila M; de Miguel E
Endereço:Institute of Environmental Assessment and Water Research (IDÆA-CSIC), C/Jordi Girona 18-24, 08034 Barcelona, Spain. teresa.moreno@idaea.csic.es.
Título:Formation and alteration of airborne particles in the subway environment.
Fonte:Environ Sci Process Impacts; 19(1):59-64, 2017 Jan 25.
ISSN:2050-7895
País de publicação:England
Idioma:eng
Resumo:Most particles in the rail subway environment are sub-micron sized ferruginous flakes and splinters generated mechanically by frictional wear of brake pads, wheels and rails. To better understand the mechanisms of formation and the alteration processes affecting inhalable particles in subways, PM samples (1-2.5 µm and 2.5-10 µm) were collected in the Barcelona Metro and then studied under a scanning electron microscope. Most particles in these samples are hematitic (up to 88%), with relatively minor amounts of mineral matter (up to 9%) and sulphates (up to 5%). Detailed microscopy (using back scattered and TEM-DRX imaging) reveals how many of the metallic particles comprise the metallic Fe nucleus surrounded by hematite (Fe O ) and a coating of sulphate and chloride salts mixed with mineral matter (including Ca-carbonates, clay minerals and quartz). These observations record the emission of fine to ultrafine FePM by frictional wear at elevated temperatures that promote rapid partial (or complete) oxidation of the native metal. Water condensing on the PM surface during cooling leads to the adsorption of inorganic mineral particles that coat the iron oxide. The distinctively layered polymineralic structure that results from these processes is peculiar to particles generated in the subway environment and very different from PM typically inhaled outdoors.
Tipo de publicação: JOURNAL ARTICLE
Nome de substância:0 (Air Pollutants); 0 (Ferric Compounds); 0 (Metals); 0 (Particulate Matter); 1K09F3G675 (ferric oxide); E1UOL152H7 (Iron)


  2 / 3179 MEDLINE  
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PMID:28166875
Autor:Pliner EM; Seo NJ; Beschorner KE
Endereço:Department of Bioengineering, 3700 O'hara St. #302, University of Pittsburgh, Pittsburgh, PA 15261, USA.
Título:Factors affecting fall severity from a ladder: Impact of climbing direction, gloves, gender and adaptation.
Fonte:Appl Ergon; 60:163-170, 2017 Apr.
ISSN:1872-9126
País de publicação:England
Idioma:eng
Resumo:Ladder falls cause many fatal injuries. The factors that affect whether a ladder perturbation leads to a fall are not well understood. This study quantified the effects of several factors on a person's ability to recover from a ladder perturbation. Thirty-five participants each experienced six unexpected ladder missteps, for three glove conditions (bare hands, high friction, low friction) and two climbing directions (ascent, descent). Fall severity was increased during ladder descent (p < 0.001). Gloves did not affect fall severity. Females compared to males had greater fall severity during ascent (p < 0.001) and descent (p = 0.018). During ascent, females had greater fall severity during the second perturbation but similar fall severity to males during the other perturbations. Additional protection may be needed when descending a ladder. Also, females may benefit from targeted interventions like training. This study does not suggest that gloves are effective for preventing ladder falls.
Tipo de publicação: JOURNAL ARTICLE


  3 / 3179 MEDLINE  
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PMID:25831407
Autor:Fang X; Vitrac O
Endereço:a AgroParisTech, UMR 1145 Ingénierie Procédés Aliments , Massy , France.
Título:Predicting diffusion coefficients of chemicals in and through packaging materials.
Fonte:Crit Rev Food Sci Nutr; 57(2):275-312, 2017 Jan 22.
ISSN:1549-7852
País de publicação:England
Idioma:eng
Resumo:Most of the physicochemical properties in polymers such as activity and partition coefficients, diffusion coefficients, and their activation with temperature are accessible to direct calculations from first principles. Such predictions are particularly relevant for food packaging as they can be used (1) to demonstrate the compliance or safety of numerous polymer materials and of their constitutive substances (e.g. additives, residues…), when they are used: as containers, coatings, sealants, gaskets, printing inks, etc. (2) or to predict the indirect contamination of food by pollutants (e.g. from recycled polymers, storage ambiance…) (3) or to assess the plasticization of materials in contact by food constituents (e.g. fat matter, aroma…). This review article summarizes the classical and last mechanistic descriptions of diffusion in polymers and discusses the reliability of semi-empirical approaches used for compliance testing both in EU and US. It is concluded that simulation of diffusion in or through polymers is not limited to worst-case assumptions but could also be applied to real cases for risk assessment, designing packaging with low leaching risk or to synthesize plastic additives with low diffusion rates.
Tipo de publicação: COMPARATIVE STUDY; JOURNAL ARTICLE; REVIEW
Nome de substância:0 (Elastomers); 0 (Plastics); 0 (Polymers)


  4 / 3179 MEDLINE  
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PMID:27890159
Autor:Simeonov P; Hsiao H; Powers J; Ammons D; Kau T; Cantis D; Zwiener J; Weaver D
Endereço:Division of Safety Research, National Institute for Occupational Safety and Health, 1095 Willowdale Rd., Morgantown, WV 26505, USA. Electronic address: psimeonov@cdc.gov.
Título:Evaluation of a "walk-through" ladder top design during ladder-roof transitioning tasks.
Fonte:Appl Ergon; 59(Pt A):460-469, 2017 Mar.
ISSN:1872-9126
País de publicação:England
Idioma:eng
Resumo:This study evaluated the effect of an extension ladder "walk-through" top design on kinetic and kinematic behaviors and the outward destabilizing forces induced on the ladder during transitioning at elevation. Thirty-two male participants performed stepping tasks between a ladder top and a roof at simulated elevation in a surround-screen virtual-reality system. The experimental conditions included a "walk-through" and a standard ladder top section supported on flat and sloped roof surfaces. Three force platforms were placed under the ladder section and in the roof to measure propulsion forces during transitions. A motion measurement system was used to record trunk kinematics. The frictional demand at the virtual ladder base was also calculated. The results indicate that under optimal ladder setup (angle 75.5 °), the frictional demand at the ladder base remains relatively small for all experimental conditions. Also, the "walk through" ladder top eased the ladder-to-roof transitions but not the roof-to-ladder transitions.
Tipo de publicação: JOURNAL ARTICLE


  5 / 3179 MEDLINE  
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PMID:27890145
Autor:Chang WR; Chang CC; Lesch MF; Matz S
Endereço:Liberty Mutual Research Institute for Safety, Hopkinton, MA 01748, USA. Electronic address: Wen.Chang@LibertyMutual.com.
Título:Gait adaptation on surfaces with different degrees of slipperiness.
Fonte:Appl Ergon; 59(Pt A):333-341, 2017 Mar.
ISSN:1872-9126
País de publicação:England
Idioma:eng
Resumo:Gait adaptation to employ different ways to avoid a potential slip is needed to continue walking safely on a new surface, especially when transitioning to a slippery surface. In this experiment, participants walked back and forth five times (trials) on surfaces with different degrees of slipperiness. The results show that trial 1 was significantly different from other trials for most of the dependent variables, especially for the low and high friction conditions. Kinematics on high and medium friction surfaces were very similar, but more adjustments were needed for low friction surfaces. The data for the first trial reflect gait after walking for 2.4 m on the walkway, not the first step onto the walkway. The current data show that gait adaptation continued beyond the first trial. Since participants in this experiment were aware of the floor conditions, the results could have important safety implications that user awareness alone might be insufficient for safe floor designs.
Tipo de publicação: JOURNAL ARTICLE


  6 / 3179 MEDLINE  
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PMID:27450600
Autor:Wall PL; Weasel J; Rometti M; Birkholz S; Gildemaster Y; Grulke L; Sahr SM; Buising CM
Título:Pressures Under 3.8cm, 5.1cm, and Side-by-Side 3.8cm-Wide Tourniquets.
Fonte:J Spec Oper Med; 16(2):28-35, 2016.
ISSN:1553-9768
País de publicação:United States
Idioma:eng
Resumo:BACKGROUND: Applications of wider tourniquet are expected to occlude arterial flow at lower pressures. We examined pressures under 3.8cm-wide, 5.1cm-wide, and side-by-side-3.8cm-wide nonelastic strap-based tourniquets. METHODS: Ratcheting Medical Tourniquets (RMT) were applied mid-thigh and mid-arm for 120 seconds with Doppler-indicated occlusion. The RMTs were a Single Tactical RMT (3.8cm-wide), a Wide RMT (5.1cm-wide), and Paired Tactical RMTs (7.6cm-total width). Tightening completion was measured at one-tooth advance past arterial occlusion, and paired applications involved alternating tourniquet tightening. RESULTS: All 96 applications on the 16 recipients reached occlusion. Paired tourniquets had the lowest occlusion pressures (ρ < .05). All pressures are given as median mmHg, minimum-maximum mmHg. Thigh application occlusion pressures were Single 256, 219-299; Wide 259, 203-287; Distal of Pair 222, 183-256; and Proximal of Pair 184, 160-236. Arm application occlusion pressures were Single 230, 189-294; Wide 212, 161-258; Distal of Pair 204, 193-254, and Proximal of Pair 168, 148-227. Pressure increases with the final tooth advance were greater for the 2 teeth/cm Wide than for the 2.5 teeth/cm Tacticals (ρ < .05). Thigh final tooth advance pressure increases were Single 40, 33-49; Wide 51, 37-65; Distal of Pair 13, 1-35; and Proximal of Pair 15, 0-30. Arm final tooth advance pressure increases were Single 49, 41-71; Wide 63, 48-77; Distal of Pair 3, 0-14; and Proximal of Pair 23, 2-35. Pressure decreases occurred under all tourniquets over 120 seconds. Thigh pressure decreases were Single 41, 32-75; Wide 43, 28-62; Distal of Pair 25, 16-37; and Proximal of Pair 22, 15-37. Arm pressure decreases were Single 28, 21-43; Wide 26, 16-36; Distal of Pair 16, 12-35; and Proximal of Pair 12, 5-24. Occlusion losses before 120 seconds occurred predominantly on the thigh and with paired applications (ρ < .05). Occlusion losses occurred in six Paired thigh applications, two Single thigh applications, and one Paired arm application. CONCLUSIONS: Side-by-side tourniquets achieve occlusion at lower pressures than single tourniquets. Additionally, pressure decreases under tourniquets over time; so all tourniquet applications require reassessments for continued effectiveness.
Tipo de publicação: COMPARATIVE STUDY; JOURNAL ARTICLE


  7 / 3179 MEDLINE  
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PMID:27354734
Autor:Martin S; Bhushan B
Endereço:Nanoprobe Laboratory for Bio and Nanotechnology and Biomimetics (NLBB), The Ohio State University, 201 West 19th Avenue, Columbus, OH 43210-1142, USA bhushan.2@osu.edu.
Título:Discovery of riblets in a bird beak (Rynchops) for low fluid drag.
Fonte:Philos Trans A Math Phys Eng Sci; 374(2073), 2016 Aug 06.
ISSN:1364-503X
País de publicação:England
Idioma:eng
Resumo:Riblet structures found on fast-swimming shark scales, such as those found on a mako shark, have been shown to reduce fluid drag. In previous experimental and modelling studies, riblets have been shown to provide drag reduction by lifting vortices formed in turbulent flow, decreasing overall shear stresses. Skimmer birds (Rynchops) are the only birds to catch fish in flight by flying just above the water surface with a submerged beak to fish for food. Because they need to quickly catch prey, reducing drag on their beak is advantageous. For the first time, riblet structures found on the beak of the skimmer bird have been studied experimentally and computationally for low fluid drag properties. In this study, skimmer replicas were studied for drag reduction through pressure drop in closed-channel, turbulent water flow. Pressure drop measurements are compared for black and yellow skimmer beaks in two configurations, and mako shark skin. In addition, two configurations of skimmer beak were modelled to compare drag properties and vortex structures. Results are discussed, and a conceptual model is presented to explain a possible drag reduction mechanism in skimmers.This article is part of the themed issue 'Bioinspired hierarchically structured surfaces for green science'.
Tipo de publicação: JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T


  8 / 3179 MEDLINE  
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PMID:27159940
Título:Oral Pathology Quiz #90. Case Number 1. Frictional keratosis.
Fonte:J N J Dent Assoc; 87(1):12, 16, 2016.
ISSN:0093-7347
País de publicação:United States
Idioma:eng
Tipo de publicação: CASE REPORTS; JOURNAL ARTICLE


  9 / 3179 MEDLINE  
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PMID:27125094
Autor:Filep R; Ilea M; Turnea M; Arotaritei D; Rotariu M; Popescu M
Título:COMBINED EFFECT OF THERMAL LOAD AND MECHANICAL LOAD IN TRANSTIBIAL PROSTHESIS. AN EMPIRICAL STUDY.
Fonte:Rev Med Chir Soc Med Nat Iasi; 120(1):186-91, 2016 Jan-Mar.
ISSN:0048-7848
País de publicação:Romania
Idioma:eng
Resumo:UNLABELLED: Probably the most important factor in evaluating a patient's prosthesis is quality of life. Transtibial amputations, are among the most frequently performed major limb amputations. Many individuals with transtibial amputations successfully achieve rehabilitation at or near their preamputation levels. Discomfort in prosthetic sockets continues to be a critical challenge faced by both prosthetists and amputees. MATERIAL AND METHODS: This paper proposes a fusion Graphic User Interface that combines two types of information (pressure and temperature). Data from pressure sensors and thermistors (an electrical resistor whose resistance is greatly reduced by heating, used for measurement and control) placed on the stump in transtibial prosthetics are collected in real time using a National Instruments Data Acquisition device. RESULTS: All the data stored in files are available for offline processing. The user has the possibility to analyse the signal by zooming or positioning the marker and window on different parts of signal. A complex analysis that involves the pressure and temperature for a location (where both sensors are placed) is available in time domain. CONCLUSIONS: Blunt-prosthesis interface is characterized by few parameters among the most important are pressure and friction. The action of these parameters during static and dynamic stage is very important because their actions can produce lesions of skin at the level of interface. Despite the advancements in surgical techniques and prostheses, much still needs to be done. We made certain that the sensors were in the same location by pressing on specific cells on the residual limb during various stages of the experimentation. The highest pressures recorded were during the stance phase of walking. The curve that shows the temperature evolution or pressure in one point could differ in different points from patient to patient.
Tipo de publicação: JOURNAL ARTICLE


  10 / 3179 MEDLINE  
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PMID:27096616
Autor:Hayat T; Jabeen S; Shafiq A; Alsaedi A
Endereço:Department of Mathematics, Quaid-I-Azam University, 45320, Islamabad, 44000, Pakistan.
Título:Radiative Squeezing Flow of Second Grade Fluid with Convective Boundary Conditions.
Fonte:PLoS One; 11(4):e0152555, 2016.
ISSN:1932-6203
País de publicação:United States
Idioma:eng
Resumo:Influence of magnetohydrodynamic (MHD) flow between two parallel disks is considered. Heat transfer analysis is disclosed due to thermal radiation and convective boundary condition. Appropriate transformations are invoked to obtain the ordinary differential system. This system is solved using homotopic approach. Convergence of the obtained solution is discussed. Variations of embedded parameters into the governing problems are graphically discussed. Skin friction coefficient and Nusselt number are numerically computed and analyzed. It is noticed that temperature profile is increasing function of radiation parameter.
Tipo de publicação: JOURNAL ARTICLE



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