Podle výsledků několika etap šetření respiračního zdraví českých dětí prováděných v rámci Systému monitorování zdravotního stavu obyvatelstva ČR v minulých dvou dekádách je v Moravskoslezském kraji (MSK) prevalence respiračních alergií, opakovaných zánětů dýchacích cest i nespecifických respiračních symptomů vyšší, než je republikový průměr. Vzhledem ke zvýšenému znečištění ovzduší ve velké části tohoto kraje bylo naším cílem potvrdit předpoklad, že prevalence alergických onemocnění a respiračních obtíží dětí souvisí s prostorově variabilní kvalitou ovzduší. K tomu byla použita metoda shlukové analýzy (rozdělení kraje na oblasti lišící se charakterem dlouhodobého znečištění ovzduší) a mnohonásobné logistické regrese (porovnání prevalence respiračních onemocnění mezi těmito oblastmi). V dalším kroku byla plošným modelováním pomocí generalizovaného aditivního modelu odhadnuta pravděpodobná prevalence respiračních alergií/onemocnění/symptomů. Podkladem pro analýzy bylo dotazníkové šetření, provedené v 18 městech MSK v roce 2015, kterého se zúčastnilo více než 7 000 dětí ve věku 5, 9, 13 a 17 let. Dlouhodobá expozice znečištěnému ovzduší byla hodnocena na základě map průměrných koncentrací suspendovaných prachových částic PM10,,SO2 a oxidu dusičitého za období 2009-2013. Výsledky potvrdily předpoklad, že prevalence sledovaných respiračních onemocnění je, s výjimkou diagnostikovaného astmatu, ovlivněna prostorově variabilní kvalitou ovzduší, a přispěly k odhadu výskytu sledovaných respiračních alergií a onemocnění dětí v MS kraji.
Repeated surveys of respiratory health among Czech children conducted by the National Institute of Public Health in the past two decades revealed a higher prevalence of respiratory allergies, recurrent respiratory infections and non-specific respiratory symptoms in the Moravian-Silesian Region (MS Region) than the national average levels. In view of the substantial pollution of large areas in that region, our aim was to examine how the prevalence of allergic diseases and respiratory symptoms in children is related to spatially variable air quality. Cluster analysis (division of the region into areas differring by the characteristics of long-term air pollution) and multiple logistic regressions (comparing the respiratory diseases prevalence among regions) were used for this purpose. In the next step, the probable prevalence of respiratory allergies/disease/symptomes was spatially modelled using the generalized additive model. The data source for the analysis was a questionnaire survey conducted in 18 MS Region cities in 2015, involving more than 7,000 children aged 5, 9, 13 and 17 years. Long-term exposure to particulate matter PM10, nitrogen dioxide and sulphur dioxide was assessed on the basis of average concentration maps for the period 2009-2013. The results confirmed the assumption that the prevalence of the surveyed respiratory diseases, with the exception of diagnosed asthma, was influenced by the spatially variable air quality and contributed to the estimation of the occurrence of respiratory allergies and other diseases in children in the MS Region.
The aim of the present paper is to provide a novel experimental approach enabling to assess the thickness of lubricant film within hip prostheses in meaning of the contribution of particular proteins. Thin film colorimetric interferometry was combined with fluorescent microscopy finding that a combination of optical methods can help to better understand the interfacial lubrication processes in hip replacements. The contact of metal femoral head against a glass disc was investigated under various operating conditions. As a test lubricant, the saline solution containing the albumin and γ-globulin in a concentration 2:1 was employed. Two different mean speeds were applied, 5.7 and 22mm/s, respectively. The measurements were carried out under pure rolling, partial negative and partial positive sliding conditions showing that kinematic conditions substantially affects the formation of protein film. Under pure rolling conditions, an increasing tendency of lubricant film independently on rolling speed was detected, while the total thickness of lubricant film can be attributed mainly to albumin. When the ball was faster than the disc (negative sliding), a very thin lubricant film was observed for lower speed with no significant effect of particular proteins. The increase in sliding speed led to the increase of film thickness mainly caused due to the presence of γ-globulin. On the contrary, when the disc was faster than the ball (positive sliding), the film formation was very complex and time dependent while both of the studied proteins have shown any qualitative change during the test, however the effect of albumin seems to be much more important. Since a very good agreement of the results was obtained, it can be concluded that the approach consisting of two optical methods can provide the fundamental information about the lubricant film formation in meaning of particular proteins while the simultaneous presence of other constituents in model synovial fluid.
An advanced surface engineering process combining micro-texture with a plasma carburising process was produced on CoCrMo femoral head, and their tribological properties were evaluated by the cutting-edge pendulum hip joint simulator coupled with thin film colorimetric interferometry. FESEM and GDOES showed that precipitation-free C S-phase with a uniform case depth of 10μm was formed across the micro-textures after duplex treatment. Hip simulator tests showed that the friction coefficient was reduced by 20% for micro-metre sized texture, and the long-term tribological property of microtexture was enhanced by the C-supersaturated crystalline microstructure formed on the surface of duplex treated CoCrMo, thereby enhancing biotribological durability significantly. In-situ colorimetric interferometry confirmed that the maximum film thickness around texture area was 530nm, indicating that the additional lubricant during sliding motion might provide exceptional bearing life.
This study investigates a tribological performance of diamond like carbon (DLC) coated micro dimpled prosthesis heads against ceramic cups in a novel pendulum hip joint simulator. The simulator enables determining friction coefficient and viscous effects of a concave shaped specimen interface (conformal contact). Two types of DLC such as hydrogenated amorphous carbon (a-C:H) and tetrahedral amorphous carbon (Ta-C) and one set of micro dimple (diameter of 300µm, depth of 70µm, and pitch of 900µm) were fabricated on metallic prosthesis heads. The experiment results reveal a significant friction coefficient reduction to the 'dimpled a-C:H/ceramic' prosthesis compared to a 'Metal (CoCr)/ceramic' prosthesis because of their improved material and surface properties and viscous effect. The post-experiment surface analysis displays that the dimpled a-C:H yielded a minor change in the surface roughness, and generated a larger sizes of wear debris (40-200nm sized, equivalent diameter), a size which could be certainly stored in the dimple, thus likely to reducing their possible third body abrasive wear rate. Thus, dimpled a:C-H can be used as a 'metal on ceramic hip joint interface', whereas the simulator can be utilized as an advanced bio-tribometer.
