Technical analysis of possibility to replace the carbonitriding with sulfonitriding process to reduce the frictional resistances and increase the service life

katedra: KMT; přílohy: 1 CD ROM; rozsah: 55In the thesis the modification of surface through thermal-chemical treatment on final elements of MQ 200 gear box to carry out the analysis of possibility to replace the carbonitriding with sulfonitriding process is undertaken. In the theoretical part the typical processes of thermal-chemical treatments and the wear model arising during machine elements' mating are described. There is also the evaluation of sulfonitriding from technical, economical and ecological point of view brought up. In the experimental part the characteristics of obtained layers by using of following testing techniques: optical microscopy, X-ray microanalysis, microhardness measurements and tribological tests using the Pin-On-Disc method is carried out. The obtained test results are shown in a form of pictures, diagrams and tables.Práce se zaobírala modifikací povrchů chemickotepelným zpracováním na připravených součástech převodové skříně MQ 200 za účelem provedení analýzy možnosti zastoupení nitrocementovaného zpracování procesem sulfonitridace. V teoretické části byly popsány typické procesy chemickotepelného zpracování a rovněž formy úbytků vystupující během vzájemné spolupráce součástí strojů. Rovněž se zaobírala hodnocením sulfonitridace z technického, ekonomického a také ekologického hlediska. V experimentální části byla provedena charakteristika získaných vrstev s použitím následujících zkušebních technik: optická mikroskopie, rentgenová mikroanalýza, měření mikrotvrdosti a také tribologické zkoušky metodou Pin-On-Disc. Získané výsledky zkoušek byly představeny v podobě fotografií, grafů a zároveň tabulek

Are bone erosions detected by magnetic resonance imaging and ultrasonography true erosions? A comparison with computed tomography in rheumatoid arthritis metacarpophalangeal joints

The objective of the study was, with multidetector computed tomography (CT) as the reference method, to determine whether bone erosions in rheumatoid arthritis (RA) metacarpophalangeal (MCP) joints detected with magnetic resonance imaging (MRI) and ultrasonography (US), but not with radiography, represent true erosive changes. We included 17 RA patients with at least one, previously detected, radiographically invisible MCP joint MRI erosion, and four healthy control individuals. They all underwent CT, MRI, US and radiography of the 2nd to 5th MCP joints of one hand on the same day. Each imaging modality was evaluated for the presence of bone erosions in each MCP joint quadrant. In total, 336 quadrants were examined. The sensitivity, specificity and accuracy, respectively, for detecting bone erosions (with CT as the reference method) were 19%, 100% and 81% for radiography; 68%, 96% and 89% for MRI; and 42%, 91% and 80% for US. When the 16 quadrants with radiographic erosions were excluded from the analysis, similar values for MRI (65%, 96% and 90%) and US (30%, 92% and 80%) were obtained. CT and MRI detected at least one erosion in all patients but none in control individuals. US detected at least one erosion in 15 patients, however, erosion-like changes were seen on US in all control individuals. Nine patients had no erosions on radiography. In conclusion, with CT as the reference method, MRI and US exhibited high specificities (96% and 91%, respectively) in detecting bone erosions in RA MCP joints, even in the radiographically non-erosive joints (96% and 92%). The moderate sensitivities indicate that even more erosions than are seen on MRI and, particularly, US are present. Radiography exhibited high specificity (100%) but low sensitivity (19%). The present study strongly indicates that bone erosions, detected with MRI and US in RA patients, represent a loss of calcified tissue with cortical destruction, and therefore can be considered true bone erosions

Antibodies to infliximab and adalimumab in patients with rheumatoid arthritis in clinical remission:a cross-sectional study

Objective. To investigate if antibodies towards biological TNF-α inhibitors (anti-TNFi Abs) are present in patients with rheumatoid arthritis (RA) in clinical remission and to relate any anti-TNFi Abs to circulating level of TNF-α inhibitor (TNFi). Methods. Patients with RA, treated with infliximab or adalimumab, and in clinical remission (DAS28(CRP) < 2.6) were included from 6 out-patient clinics. In blood samples, presence of anti-TNFi Abs was determined by radioimmunoassay, and concentration of bioactive TNFi was measured by a cell-based reporter gene assay. Results. Anti-TNFi Abs were present in 8/44 patients (18%) treated with infliximab and 1/49 patients (2%) treated with adalimumab (p=0.012). In the former group, anti-TNFi Abs corresponded with low levels of TNFi (p=0.048). Anti-TNFi Ab-positive patients had shorter disease duration at initiation of TNFi therapy (p=0.023) but were similar for the rest of the compared parameters. Conclusions. In RA patients in clinical remission, anti-TNFi Abs occur frequently in patients treated with infliximab, while they occur rarely in patients treated with adalimumab. Presence of anti-infliximab Abs is accompanied by low or undetectable levels of infliximab. These data suggest that continued infliximab treatment may be redundant in a proportion of RA patients treated with infliximab and in clinical remission

Current state of musculoskeletal ultrasound training and implementation in Europe: results of a survey of experts and scientific societies

Objective. To document the current state of musculoskeletal US (MSUS) training and extent of implementation among rheumatologists in the member countries of EULAR. Methods. An English-language questionnaire, divided into five sections (demographics, clinical use of MSUS, overall MSUS training for rheumatologists, MSUS education in the rheumatology training curriculum and education in MSUS offered by the national rheumatology society) was sent by e-mail to three different groups: (i) all national rheumatology societies of EULAR; (ii) all national societies of the European Federation of Societies for Ultrasound in Medicine and Biology; and (iii) 19 senior rheumatologists involved in MSUS training from 14 European countries. Results. Thirty-one (70.5%) out of 44 countries responded to the questionnaire (59.1% of national rheumatology societies, 34.5% of the national US societies and 100% of expert ultrasonographers). Rheumatology was listed among medical specialities that mainly perform MSUS in 20 (64.5%) countries; however, in most [19 (63.3%)] countries <10% of rheumatologists routinely perform MSUS in clinical practice. Training varies widely from country to country, with low rates of competency assessment. MSUS education is part of the rheumatology training curriculum in over half the surveyed countries, being compulsory in 7 (22.6%) countries and optional in 11 (35.5%). Conclusions. This study confirms the high uptake of MSUS across Europe. The reported variation in training and practice between countries suggests a need for standardization in areas including training guideline

Practice of ultrasound-guided arthrocentesis and joint injection, including training and implementation, in Europe: results of a survey of experts and scientific societies

Objectives. To document the practice and training opportunities of US-guided arthrocentesis and joint injection (UGAJ) among rheumatologists in the member countries of the European League Against Rheumatism (EULAR). Methods. An English-language questionnaire, containing questions on demographics, clinical and practical aspects of UGAJ, training options in UGAJ for rheumatologists, UGAJ education in the rheumatology training curriculum and other structured education programmes in UGAJ was sent to three different groups: (i) all national rheumatology societies of EULAR; (ii) all national societies of the European Federation of Societies for Ultrasound in Medicine and Biology (EFSUMB); and (iii) 22 senior rheumatologists involved in EULAR musculoskeletal US training from 14 European countries, who were also asked to circulate the questionnaire among relevant colleagues. Results. Thirty-three (75%) of 44 countries responded to the questionnaire (61.3% of national rheumatology societies, 25% of the national US societies and 100% of expert ultrasonographers). In the majority of countries (85%) 80%) rate of rheumatologists performing conventional joint injection in most of the surveyed countries. The reported variations in practice and the lack of available structured training programmes for trainees in most countries indicates the need for standardization in areas including training guideline

Musculoskeletal ultrasound including definitions for ultrasonographic pathology

Ultrasound (US) has great potential as an outcome in rheumatoid arthritis trials for detecting bone erosions, synovitis, tendon disease, and enthesopathy. It has a number of distinct advantages over magnetic resonance imaging, including good patient tolerability and ability to scan multiple joints in a short period of time. However, there are scarce data regarding its validity, reproducibility, and responsiveness to change, making interpretation and comparison of studies difficult. In particular, there are limited data describing standardized scanning methodology and standardized definitions of US pathologies. This article presents the first report from the OMERACT ultrasound special interest group, which has compared US against the criteria of the OMERACT filter. Also proposed for the first time are consensus US definitions for common pathological lesions seen in patients with inflammatory arthritis