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Pesquisa : G01.374.618 [Categoria DeCS]
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PMID:29401577
Autor:Ryss AY
Título:The simplest "field" methods for extractin of nematodes from plants, wood, insects and soil, with additional description how to keep extracted nematodes alive for a long time.
Fonte:Parazitologiia; 51(1):57-67, 2017 Jan-Feb.
ISSN:0031-1847
País de publicação:Russia (Federation)
Idioma:eng
Resumo:The simplest modification of the dynamic extraction method using cottonwool filter based on the Baermann funnel principle, is described. This modification excludes the funnel because a great share of Sticky worms attach to sloping walls of a funnel and thus do not reach the collector Eppendorf tube. But the main principle of the Baermann funnel is used, I. e. sinking down of actively moving heavy narrow bodies via wide holes of filter and thus separating the active worms from passive non-Brownian moving substrate particles, which do not pass the filter and remain above it. This principle is illustrated because it has never been described before. In the proposed modification any sloping walls in the extraction paths are excluded and thus the probability to attach sticky nemotodes to walls is also excluded; only cylindrical equipment with abrupt vertical walls is used; procedures are extremely simplified to be user-friendly for beginners: only filter (cotton pads), Eppendorf tubes, plastic glasses and narrow PVC tubing are applied. The new simplified modification allows one to collect nematodes by non-professional workers, e. g. in Polar expeditions without microscopic study of results. As an addition, an efficient method to maintain extracted nematodes alive is proposed, using the "effect of water film" in foam rubber inside the Eppendorf tube. To maintain nematodes alive during several months it is recommended to suppress bacteria via addition of 0.2-0.4% formaldehyde solution and then keep the tube with nematodes in a refrigerator.
Tipo de publicação: RESEARCH SUPPORT, NON-U.S. GOV'T; JOURNAL ARTICLE
Nome de substância:0 (Soil)


  2 / 3380 MEDLINE  
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PMID:29324875
Autor:Özel C; Gürgenç T
Endereço:Department of Mechanical Engineering, Firat University, Engineering Faculty, Elazig, Turkey.
Título:Effect of heat input on microstructure, wear and friction behavior of (wt.-%) 50FeCrC-20FeW-30FeB coating on AISI 1020 produced by using PTA welding.
Fonte:PLoS One; 13(1):e0190243, 2018.
ISSN:1932-6203
País de publicação:United States
Idioma:eng
Resumo:In this study, AISI 1020 steel surface was coated in different heat inputs with (wt.-%) 50FeCrC-20FeW-30FeB powder mixture by using plasma transferred arc (PTA) welding method. The microstructure of the coated samples were investigated by using optical microscope (OM), scanning electron microscope (SEM), X-ray diffraction (XRD) and energy dispersive X-ray (EDS). The hardness was measured with micro hardness test device. The dry sliding wear and friction coefficient properties were determined using a block-on-disk type wear test device. Wear tests were performed at 19.62 N, 39.24 N, 58.86 N load and the sliding distance of 900 m. The results were shown that different microstructures formed due to the heat input change. The highest average micro hardness value was measured at 1217 HV on sample coated with low heat input. It was determined that the wear resistance decreased with increasing heat input.
Tipo de publicação: JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
Nome de substância:0 (Alloys)


  3 / 3380 MEDLINE  
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PMID:29205226
Autor:Bascou J; Sauret C; Lavaste F; Pillet H
Endereço:Institution Nationale des Invalides, Centre d'Etudes et de Recherche sur l'Appareillage des Handicapés, Woippy, France.
Título:Is bearing resistance negligible during wheelchair locomotion? Design and validation of a testing device.
Fonte:Acta Bioeng Biomech; 19(3):165-176, 2017.
ISSN:1509-409X
País de publicação:Poland
Idioma:eng
Resumo:PURPOSE: Among the different resistances occurring during wheelchair locomotion and that limit the user autonomy, bearing resistance is generally neglected, based on a few studies carried out in static conditions and by manufacturer's assertion. Therefore, no special attention is generally paid to the mounting and the maintenance of manual wheelchair bearings. However, the effect of inadequate mounting or maintenance on wheelchair bearing resistance has still to be clarified. This study aimed at filling this gap by developing and validating a specific device allowing the measurement of wheelchair bearing friction, characterized by low speed velocities, with an accuracy lower than 0.003 Nm. METHODS: The bearing resistance measured by the device was compared to free deceleration measurement, intra and inter operator reproducibility were assessed. A factorial experiment allowed the effects of various functioning parameters (axial and radial loads, velocity) to be classified. RESULTS: The device allowed significant differences in the bearing resistance of static and rotating conditions to be measured, even if a relatively high proportionality was found between both conditions. The factorial experiment allowed the expected impact of the radial load on bearing resistance as well as the predominant effect of the axial load to be demonstrated. CONCLUSIONS: As a consequence, it appeared that the control of the axial load is compulsory for measurement purposes or during wheel mounting, to avoid significant increase of global resistance during wheelchair locomotion. The findings of this study could help enhancing the models which assess manual wheelchair mechanical power from its settings and use conditions.
Tipo de publicação: EVALUATION STUDIES; JOURNAL ARTICLE; VALIDATION STUDIES


  4 / 3380 MEDLINE  
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PMID:29205219
Autor:Vogel D; Rathay A; Teufel S; Ellenrieder M; Zietz C; Sander M; Bader R
Endereço:Biomechanics and Implant Technology Research Laboratory, Department of Orthopaedics, University of Rostock, Rostock, Germany.
Título:Experimental analysis of insertion torques and forces of threaded and press-fit acetabular cups by means of ex vivo and in vivo measurements.
Fonte:Acta Bioeng Biomech; 19(3):155-163, 2017.
ISSN:1509-409X
País de publicação:Poland
Idioma:eng
Resumo:PURPOSE: In THA a sufficient primary implant stability is the precondition for successful secondary stability. Industrial foams of different densities have been used for primary stability investigations. The aim of this study was to analyse and compare the insertion behaviour of threaded and press-fit cups in vivo and ex vivo using bone substitutes with various densities. METHODS: Two threaded (Bicon Plus®, Trident® TC) and one press-fit cup (Trident PSL®) were inserted by orthopaedic surgeons (S1, S2) into 10, 20 and 31 pcf blocks, using modified surgical instruments allowing measurements of the insertion forces and torques. Furthermore, the insertion behaviour of two cups were analysed intraoperatively. RESULTS: Torques for the threaded cups increased while bone substitute density increased. Maximum insertion torques were observed for S2 with 102 Nm for the Bicon Plus® in 20 pcf blocks and 77 Nm for the Trident® TC in 31 pcf blocks, which compares to the in vivo measurement (85 Nm). The average insertion forces for the press-fit cup varied from 5.2 to 6.8 kN (S1) and 7.2-11.5 kN (S2) ex vivo. Intraoperatively an average insertion force of 8.0 kN was determined. CONCLUSIONS: Implantation behaviour was influenced by acetabular cup design, bone substitute and experience of the surgeon. No specific density of bone substitute could be favoured for ex vivo investigations on the implantation behaviour of acetabular cups. The use synthetic bone blocks of high density (31 pcf) led to problems regarding cup orientation and seating. Therefore, bone substitutes used should be critically scrutinized in terms of the comparability to the in vivo situation.
Tipo de publicação: JOURNAL ARTICLE


  5 / 3380 MEDLINE  
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PMID:28452830
Autor:Janssen L; Allard NAE; Ten Haaf DSM; van Romburgh CPP; Eijsvogels TMH; Hopman MTE
Título:First-Aid Treatment for Friction Blisters: "Walking Into the Right Direction?"
Fonte:Clin J Sport Med; 28(1):37-42, 2018 Jan.
ISSN:1536-3724
País de publicação:United States
Idioma:eng
Resumo:OBJECTIVE: Blisters are common foot injuries during and after prolonged walking. However, the best treatment remains unclear. The aim of the study was to compare the effect of 2 different friction blister treatment regimens, wide area fixation dressing versus adhesive tape. DESIGN: A prospective observational cohort study. SETTING: The 2015 Nijmegen Four Days Marches in the Netherlands. PARTICIPANTS: A total of 2907 participants (45 ± 16 years, 52% men) were included and received 4131 blister treatments. INTERVENTIONS: Blisters were treated with either a wide area fixation dressing or adhesive tape. MAIN OUTCOME MEASURES: Time of treatment application was our primary outcome. In addition, effectiveness and satisfaction were evaluated in a subgroup (n = 254). During a 1-month follow-up period, blister healing, infection and the need for additional medical treatment were assessed in the subgroup. RESULTS: Time of treatment application was lower (41.5 minutes; SD = 21.6 minutes) in the wide area fixation dressing group compared with the adhesive tape group (43.4 minutes; SD = 25.5 minutes; P = 0.02). Furthermore, the wide area fixation dressing group demonstrated a significantly higher drop-out rate (11.7% vs 4.0%, P = 0.048), delayed blister healing (51.9% vs 35.3%, P = 0.02), and a trend toward lower satisfaction (P = 0.054) when compared with the adhesive tape group. CONCLUSIONS: Wide area fixation dressing decreased time of treatment application by 2 minutes (4.5%) when compared with adhesive tape. However, because of lower effectiveness and a trend toward lower satisfaction, we do not recommend the use of wide area fixation dressing over adhesive tape in routine first-aid treatment for friction blisters.
Tipo de publicação: JOURNAL ARTICLE; OBSERVATIONAL STUDY


  6 / 3380 MEDLINE  
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PMID:28743045
Autor:Prata AA; Santos JM; Timchenko V; Reis NC; Stuetz RM
Endereço:UNSW Water Research Centre, School of Civil and Environmental Engineering, The University of New South Wales, Sydney, NSW, 2052, Australia.
Título:Wind friction parametrisation used in emission models for wastewater treatment plants: A critical review.
Fonte:Water Res; 124:49-66, 2017 11 01.
ISSN:1879-2448
País de publicação:England
Idioma:eng
Resumo:Emission models are widely applied tools for estimating atmospheric emissions from wastewater treatment plants (WWTPs). The friction velocity u is a key variable for the modelling of emissions from passive liquid surfaces in WWTPs. This work evaluated different parametrisations of u for passive liquid surfaces at the scale of WWTP units, which present relatively small fetches, based on available wind friction and wave data measured at wind-wave tanks (fetches spanning from approximately 3 to 100 m, and wind speeds from 2 to 17 m s ). The empirical correlation by Smith (1980; J. Phys. Oceanogr. 10, 709-726), which has been frequently adopted in air emission models (despite the fact that it was originally derived for the ocean) presented a general tendency to overestimate u , with significant (although not extreme) relative errors (mean and maximum errors of 13.5% and 36.6%, respectively); the use of Charnock's relation, with Charnock constant 0.010, performed in a very similar manner (mean and maximum errors of 13.3% and 37.8%, respectively). Better estimates of u were achieved by parametrisations based on the significant wave steepness. Simplified correlations between the wind drag and the non-dimensional fetch were obtained. An approach was devised, comprising the use of Charnock's relation (with Charnock constant 0.010) and of these simplified correlations, depending on the ranges of frequency of the peak waves, fetch and wind speed. The proposed approach predicted u with improved accuracy (mean, maximum and 95%-percentile relative errors of 6.6%, 16.7% and 13.9%, respectively), besides being able to incorporate the influence of the fetch in the wind drag, thus taking into account the size of the tanks in the WWTPs.
Tipo de publicação: JOURNAL ARTICLE; REVIEW; RESEARCH SUPPORT, NON-U.S. GOV'T
Nome de substância:0 (Air Pollutants); 0 (Waste Water)


  7 / 3380 MEDLINE  
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PMID:29065112
Autor:Liu H; Zong Q; Lv H; Jin J
Endereço:College of Water Conservancy and Architectural Engineering, Shihezi University, Shihezi, China.
Título:Analytical equation for outflow along the flow in a perforated fluid distribution pipe.
Fonte:PLoS One; 12(10):e0185842, 2017.
ISSN:1932-6203
País de publicação:United States
Idioma:eng
Resumo:Perforated fluid distribution pipes have been widely used in agriculture, water supply and drainage, ventilation, the chemical industry, and other sectors. The momentum equation for variable mass flow with a variable exchange coefficient and variable friction coefficient was developed by using the momentum conservation method under the condition of a certain slope. The change laws of the variable momentum exchange coefficient and the variable resistance coefficient along the flow were analyzed, and the function of the momentum exchange coefficient was given. According to the velocity distribution of the power function, the momentum equation of variable mass flow was solved for different Reynolds numbers. The analytical solution contains components of pressure, gravity, friction and momentum and reflects the influence of various factors on the pressure distribution along the perforated pipe. The calculated results of the analytical solution were compared with the experimental values of the study by Jin et al. 1984 and Wang et al. 2001 with the mean errors 8.2%, 3.8% and 2.7%, and showed that the analytical solution of the variable mass momentum equation was qualitatively and quantitatively consistent with the experimental results.
Tipo de publicação: JOURNAL ARTICLE
Nome de substância:059QF0KO0R (Water)


  8 / 3380 MEDLINE  
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PMID:28886102
Autor:Sonntag R; Braun S; Al-Salehi L; Reinders J; Mueller U; Kretzer JP
Endereço:Laboratory of Biomechanics and Implant Research, Clinic for Orthopedics and Trauma Surgery, Heidelberg University Hospital, Heidelberg, Germany.
Título:Three-dimensional friction measurement during hip simulation.
Fonte:PLoS One; 12(9):e0184043, 2017.
ISSN:1932-6203
País de publicação:United States
Idioma:eng
Resumo:OBJECTIVES: Wear of total hip replacements has been the focus of many studies. However, frictional effects, such as high loading on intramodular connections or the interface to the bone, as well as friction associated squeaking have recently increased interest about the amount of friction that is generated during daily activities. The aim of this study was thus to establish and validate a three-dimensional friction setup under standardized conditions. MATERIALS AND METHODS: A standard hip simulator was modified to allow for high precision measurements of small frictional effects in the hip during three-dimensional hip articulation. The setup was verified by an ideal hydrostatic bearing and validated with a static-load physical pendulum and an extension-flexion rotation with a dynamic load profile. Additionally, a pendulum model was proposed for screening measurement of frictional effects based on the damping behavior of the angular oscillation without the need for any force/moment transducer. Finally, three-dimensional friction measurements have been realized for ceramic-on-polyethylene bearings of three different sizes (28, 36 and 40 mm). RESULTS: A precision of less than 0.2 Nm during three-dimensional friction measurements was reported, while increased frictional torque (resultant as well as taper torque) was measured for larger head diameters. These effects have been confirmed by simple pendulum tests and the theoretical model. A comparison with current literature about friction measurements is presented. CONCLUSIONS: This investigation of friction is able to provide more information about a field that has been dominated by the reduction of wear. It should be considered in future pre-clinical testing protocols given by international organizations of standardization.
Tipo de publicação: JOURNAL ARTICLE


  9 / 3380 MEDLINE  
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PMID:28886084
Autor:Groves D; Fisher J; Williams S
Endereço:Institute of Medical and Biological Engineering, School of Mechanical Engineering, University of Leeds, Leeds, United Kingdom.
Título:An in vitro simulation method for the tribological assessment of complete natural hip joints.
Fonte:PLoS One; 12(9):e0184226, 2017.
ISSN:1932-6203
País de publicação:United States
Idioma:eng
Resumo:The use of hip joint simulators to evaluate the tribological performance of total hip replacements is widely reported in the literature, however, in vitro simulation studies investigating the tribology of the natural hip joint are limited with heterogeneous methodologies reported. An in vitro simulation system for the complete natural hip joint, enabling the acetabulum and femoral head to be positioned with different orientations whilst maintaining the correct joint centre of rotation, was successfully developed for this study. The efficacy of the simulation system was assessed by testing complete, matched natural porcine hip joints and porcine hip hemiarthroplasty joints in a pendulum friction simulator. The results showed evidence of biphasic lubrication, with a non-linear increase in friction being observed in both groups. Lower overall mean friction factor values in the complete natural joint group that increased at a lower rate over time, suggest that the exudation of fluid and transition to solid phase lubrication occurred more slowly in the complete natural hip joint compared to the hip hemiarthroplasty joint. It is envisaged that this methodology will be used to investigate morphological risk factors for developing hip osteoarthritis, as well as the effectiveness of early interventional treatments for degenerative hip disease.
Tipo de publicação: JOURNAL ARTICLE


  10 / 3380 MEDLINE  
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PMID:28682544
Autor:Guoxin H; Ying Y; Yuemei J; Wenjing X
Endereço:Fuzhou Medical College, Nanchang University, Fuzhou 344000, China.
Título:[Study on friction and wear properties of dental zirconia ceramics processed by microwave and conventional sintering methods].
Fonte:Hua Xi Kou Qiang Yi Xue Za Zhi; 35(2):150-154, 2017 Apr 01.
ISSN:1000-1182
País de publicação:China
Idioma:chi
Resumo:OBJECTIVE: This study evaluated the wear of an antagonist and friction and wear properties of dental zirconia ceramic that was subjected to microwave and conventional sintering methods. METHODS: Ten specimens were fabricated from Lava brand zirconia and randomly assigned to microwave and conventional sintering groups. A profile tester for surface roughness was used to measure roughness of the specimens. Wear test was performed, and steatite ceramic was used as antagonist. Friction coefficient curves were recorded, and wear volume were calculated. Finally, optical microscope was used to observe the surface morphology of zirconia and steatite ceramics. Field emission scanning electron microscopy was used to observe the microstructure of zirconia. RESULTS: Wear volumes of microwave and conventionally sintered zirconia were (6.940±1.382)×10⁻², (7.952±1.815) ×10⁻² mm³, respectively. Moreover, wear volumes of antagonist after sintering by the considered methods were (14.189±4.745)×10⁻², (15.813±3.481)×10⁻² mm³, correspondingly. Statistically significant difference was not observed in the wear resistance of zirconia and wear volume of steatite ceramic upon exposure to two kinds of sintering methods. Optical microscopy showed that ploughed surfaces were apparent in zirconia. The wear surface of steatite ceramic against had craze, accompanied by plough. Scanning electron microscopy showed that zirconia was sintered compactly when subjected to both conventional sintering and microwave methods, whereas grains of zirconia sintered by microwave alone were smaller and more uniform. CONCLUSIONS: Two kinds of sintering methods are successfully used to produce dental zirconia ceramics with similar friction and wear properties.
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Tipo de publicação: JOURNAL ARTICLE
Nome de substância:12001-21-7 (Dental Porcelain); 3A3U0GI71G (Magnesium Oxide); 63210-56-0 (steatite); 7631-86-9 (Silicon Dioxide); C6V6S92N3C (Zirconium); S38N85C5G0 (zirconium oxide)



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