A study on the influence of prosthetic interface material in transtibial amputees’ gait

Interfaces of transtibial prosthesis have an important role in the transmission of ground reaction forces, damping gait loads and tissue protection.info:eu-repo/semantics/publishedVersio

Co-infection by human immunodeficiency virus type 1 (HIV-1) and human T cell leukemia virus type 1 (HTLV-1): does immune activation lead to a faster progression to AIDS?

<p>Abstract</p> <p>Background</p> <p>Recent data have shown that HTLV-1 is prevalent among HIV positive patients in Mozambique, although the impact of HTLV-1 infection on HIV disease progression remains controversial. Our aim was to determine the phenotypic profile of T lymphocytes subsets among Mozambican patients co-infected by HIV and HTLV-1.</p> <p>Methods</p> <p>We enrolled 29 patients co-infected by HTLV-1 and HIV (co-infected), 59 patients mono-infected by HIV (HIV) and 16 healthy controls (HC), respectively.</p> <p>For phenotypic analysis, cells were stained with the following fluorochrome-labeled anti-human monoclonal antibodies CD4-APC, CD8-PerCP, CD25-PE, CD62L-FITC, CD45RA-FITC. CD45RO-PE, CD38-PE; being analysed by four-colour flow cytometry.</p> <p>Results</p> <p>We initially found that CD4⁺T cell counts were significantly higher in co-infected, as compared to HIV groups. Moreover, CD4⁺T Lymphocytes from co-infected patients presented significantly higher levels of CD45RO and CD25, but lower levels of CD45RA and CD62L, strongly indicating that CD4⁺T cells are more activated under HTLV-1 plus HIV co-infection.</p> <p>Conclusion</p> <p>Our data indicate that HTLV-1/HIV co-infected patients progress with higher CD4⁺T cell counts and higher levels of activation markers. In this context, it is conceivable that in co-infected individuals, these higher levels of activation may account for a faster progression to AIDS.</p

Comportamento tribológico de filmes finos de W-CO-C-influência do cobalto

Tese de doutoramento em Ciências da Engenharia (Engenharia Mecânica - Ciência dos Materiais) apresentada à Fac. de Ciências e Tecnologia da Univ. de CoimbraEste estudo pretende contribuir para uma melhor compreensão dos fenómenos tribológicos que podem ocorrer entre superfícies revestidas com filmes fino

Friction of Human Skin against Different Fabrics for Medical Use

Knowledge of the tribology of human skin is essential to improve and optimize surfaces and materials in contact with the skin. Besides that, friction between the human skin and textiles is a critical factor in the formation of skin injuries, which are caused if the loads and shear forces are high enough and/or over long periods of time. This factor is of particular importance in bedridden patients, since they are not moving about or are confined to wheelchairs. Decubitus ulcers are one of the most frequently-reported iatrogenic injuries in developed countries. The risk of developing decubitus ulcers can be predicted by using the “Braden Scale for Predicting Pressure Ulcer Risk” that was developed in 1987 and contains six areas of risk (cognitive-perceptual, immobility, inactivity, moisture, nutrition, friction/shear), although there are limitations to the use of such tools. The coefficient of friction of textiles against skin is mainly influenced by: the nature of the textile, skin moisture content and ambient humidity. This study will investigate how skin friction (different anatomical regions) varies, rubbing against different types of contacting materials (i.e., fabrics for medical use) under different contact conditions and their relationship in the formation and prevention of decubitus ulcers

Skin Friction: Mechanical and Tribological Characterization of Different Papers Used in Everyday Life

The coefficient of friction for different contacting materials against skin is mainly influenced by the nature of the materials (synthetic and natural fabrics), mechanical contact parameters (interfacial pressure and sliding velocities), and physiological skin conditions (ambient humidity and skin moisture content). In the present research work, seven different types of papers used in everyday life were analyzed. The physical properties of these materials were determined through tensile tests and friction tests. By comparing mechanical properties with coefficient of friction, it was possible to conclude that the coefficient of friction is strongly correlated with the mechanical properties

Tribocorrosion Behaviour of Ti6Al4V Produced by Selective Laser Melting for Dental Implants

Additively produced Ti6Al4V implants display mechanical properties that are economically infeasible to achieve with conventional subtractive methods. The aim of the present research work was to characterize the tribocorrosion behaviour of the newly produced Ti6Al4V, also known as titanium grade 5, by a selective laser melting (SLM) technique and compare it with another specimen produced by a conventional method. It was found that the tribological properties were of the same order, with the wear rate being k= 6.3 &times; 10&minus;4 mm3/N&middot;m and k = 8.3 &times; 10&minus;4 mm3/N&middot;m for respectively, SLM and conventional method. Regarding the friction behaviour, both methods exhibited similar COF in the order of 0.41&ndash;0.51. However, electrochemically, the potentiodynamic polarization curves presented some differences mainly in the potential range of the passive films and passive current density formed, with the passive current density being lower for the SLM method

Sphere-plane methodology to evaluate the wear of titanium of dental implants: a research proposal

Abstract Objective Titanium is the most commonly used material to manufacture dental implants and abutments. Recently, zirconia abutments have been manufactured with better aesthetic properties. However, zirconia abutments are harder than titanium implants; therefore, they could wear the implant surface. Therefore, this article aims to describe a sphere-plane system that can be used to assess the wear that different abutment materials cause in the titanium of dental implants when submitted to cyclic loading. This method can be used to simulate the oral cavity, where the abutment (sphere) applies loads onto the implant (titanium plane). The spheres were made of different materials (titanium and zirconia), and the specimens were loaded for 4,000,000 cycles. The scar size and area on titanium planes were measured with stereoscopic images and analysed through profilometry. Results The wear of titanium planes was similar when tested against zirconia or titanium spheres. The sphere-plane system is a method that can be used to evaluate and quantify the wear of the titanium of dental implants, and compared with methods that use real implants, this system is simpler and less expensive. This method could facilitate further research to evaluate the wear of titanium against different materials and under different testing conditions

Influence of Different Binders and Severe Environmental Conditions on the Tribological and Electrochemical Behaviour of WC-Based Composites

Cemented carbides are highly resistant to abrasion, erosion and sliding wear and are frequently used in drilling and cutting tool operations. In the present investigation, different submicrometric (0.8 µm) WC (tungsten carbide)-based composites were developed, containing various binders of Co, Ni, NiCr, NiMo, and NiCrMo. The main objective of the work was simultaneous tribological and electrochemical characterization to investigate the mechanisms of surface degradation when subjected to mechanical wear and how they interconnect with chemical or electrochemical processes and each other. By comparison with previous tribological tests, under dry sliding and the same contact conditions of load and frequency, it can be concluded that a synergistic effect was not observed and that the solution works mainly as lubrication, resulting in increased combined wear–corrosion resistance

MOESM1 of Sphere-plane methodology to evaluate the wear of titanium of dental implants: a research proposal

Additional file 1: Figure S1. Schematic representation of the testing machine and correspondence between the sphere-plane system and implant-abutment system. This figure contains a schematic representation of the testing machine used on the article. It also shows the correspondence between the sphere and a prosthetic abutment, and between the plane and a dental implant