Unconventional methods of welding of wrought magnesium alloys

Diplomová práce je zaměřena na posouzení možností svařování tvářených slitin hořčíku konvenčními i nekonvenčními metodami. Byly k dispozici tvářené slitiny hořčíku AZ31, AZ61, ZE10 a ZE41, které byly svařeny metodami Friction Stir Welding, pulzním pevnolátkovým a kontinuálním vláknovým laserem. Byl hodnocen vliv jednotlivých metod na mikrostrukturu a základní mechanické vlastnosti svarových spojů. Ke studiu bylo využito metod světelné a rastrovací elektronové mikroskopie, zkoušky tahem a měření mikrotvrdosti dle Vickerse. Z výsledků experimentu lze konstatovat, že z hlediska zachování meze pevnosti je nejvhodnější svařování metodou Friction Stir Welding. Z porovnání mikrostruktury a základních mechanických vlastností vyplývá, že pro svařování hořčíkových slitin je vhodnější kontinuální vláknový laser. V literatuře nebyly informace o svařování metodou FSW slitin skupiny ZE uvedeny, podobná situace nastává v případě svařovaných plechů o tloušťce 0,8 mm a 1,6 mm.Master's thesis deals with consideration possibility of conventional and unconvetional welding methods of wrought magnesium alloys. Methods of Friction Stir Welding, Pulsed Nd:YAG laser and Continuous Fiber laser was used to join magnesium alloy sheets AZ31, AZ61, ZE10 and ZE41. For studying influence of processing parameters on microstructure and mechanical properties were used methods of light microscopy, scanning electron microscopy, tensile tests and microhardness measurements. The results of tensile tests show that from the point of view of keeping ultimate tensile strength is the best methods for welding magnesium alloys Friction Stir Welding. Compared with Nd:YAG laser, fiber laser give better properties of welds. From comparing microstructure and mechanical properties . It wasn't found publications about Friction Stir Welding of magnesium ZE alloys or about FSW sheets with thickness only 0,8 mm and 1,6 mm.

Research and development of surface modifications of bearing steels by means of ion nitridation

Základní požadavky kladené na součásti valivých ložisek jsou vysoká mez únavy, odolnost proti otěru a korozivzdornost. Protože kompletní výroba ložisek z materiálů, které těmito vlastnostmi disponují, by byla finančně náročná, využívají se pro zvyšování mechanických vlastností povrchové úpravy. Tato bakalářská práce se zabývá aplikací vrstev metodou iontové nitridace na ložiskové oceli. Pozorován byl vliv vstupních podmínek iontové nitridace a stavu povrchu na tribologické vlastnosti ložiskové oceli s danou povrchovou úpravou. Ke studiu byly využity metody světelné mikroskopie, měření tvrdosti dle Vickerse, rastrovací elektronové mikroskopie vybavené energiově disperzní chemickou mikroanalýzou, optické emisní spektroskopie s doutnavým výbojem a metod fázové analýzy pomocí rentgenové difrakce.Basic requirements placed on rolling bearing components include the high fatigue limit, the wear resistance and the corrosion resistance. As full production of bearings from materials with these attributes would be quite expensive, surface modifications are used to improve mechanical characteristics. This thesis deals with application of layers to the bearing steel by means of ion nitridation. It studies effects of input conditions of the ion nitridation and of the surface condition on tribological characteristics of the bearing steel with the above mentioned finishing. The study employed the interaction light microscopy, the scanning electron microscopy equipped by energy dispersive chemical microanalysis, the hardness measurement by Vickers, the glow discharge optical emission spectroscopy, and methods of the phase analysis by means of the X-ray diffraction were used.

Association between TCF7L2

Previous studies showed associations between variants in TCF7L2 gene and the therapeutic response to sulfonylureas. All sulfonylureas stimulate insulin secretion by the closure of ATP-sensitive potassium (KATP) channel. The aim of the present study was to compare TCF7L2 genotype specific effect of gliclazide binding to KATP channel A-site (Group 1) with sulfonylureas binding to AB-site (Group 2). A total of 101 patients were treated with sulfonylureas for 6 months as an add-on therapy to the previous metformin treatment. TCF7L2 rs7903146 C/T genotype was identified by real-time PCR with subsequent melting curve analysis. Analyses using the dominant genetic model showed significantly higher effect of gliclazide in the CC genotype group in comparison with combined CT + TT genotype group (1.32±0.15% versus 0.73±0.11%, Padj=0.005). No significant difference in ΔHbA1c between the patients with CC genotype and the T-allele carriers was observed in Group 2. In the multivariate analysis, only the TCF7L2 genotype (P=0.006) and the baseline HbA1c (P<0.001) were significant predictors of ΔHbA1c. After introducing an interaction term between the TCF7L2 genotype and the sulfonylurea type into multivariate model, the interaction became a significant predictor (P=0.023) of ΔHbA1c. The results indicate significantly higher difference in ΔHbA1c among the TCF7L2 genotypes in patients treated with gliclazide than in patients treated with glimepiride, glibenclamide, or glipizide

Association of JAG1 gene polymorphism with systemic blood pressure in patients with obstructive sleep apnea: a prospective cohort study

Aim To assess the effects of single nucleotide polymorphisms (SNPs) on blood pressure control in patients with obstructive sleep apnea (OSA). Methods This prospective observational cohort study, conducted between 2004 and 2014, examined the associations of SNPs of JAG1, GUCY1A3-GUCY1B3, SH2B3, and NPR3-C5orf23 genes with systolic and diastolic blood pressure (SBP, DBP) in 1179 adults evaluated for OSA with overnight polysomnography. Genotyping was performed by unlabeled probe melting analysis.Results The patients were predominantly male (69.6%, mean age 52 ± 11 years, apnea-hypopnea index 34 ± 31 episodes/h). Only JAG1 genotype was associated with SBP and DBP: compared with AA homozygotes, G allele carriers (pooled GG and AG genotype) had significantly higher morning SBP (132 ± 19 vs 129 ± 18 mm Hg; P = 0.009) and morning and evening DBP (85 ± 11 vs 83 ± 10 mm Hg, P = 0.004; 86 ± 10 vs 84 ± 10 mm Hg, P = 0.012, respectively); the differences remained significant after the correction for multiple SNPs testing. In multivariate analyses, oxygen desaturation index and JAG1 genotype independently predicted morning SBP (P = 0.001, P = 0.003, respectively) and DBP (P < 0.001, P = 0.005, respectively), and evening SBP (P = 0.019, P = 0.048, respectively) and DBP (P = 0.018, P = 0.018, respectively). Conclusion This is the first replication study of the SNPs recently linked to arterial hypertension in general population by genome-wide association studies. Our findings suggest that JAG1 genotype is related to blood pressure control in OSA: G allele was associated with higher morning and evening SBP and DBP

Macrophages and Adipocytes in Human Obesity: Adipose Tissue Gene Expression and Insulin Sensitivity During Calorie Restriction and Weight Stabilization

International audienceOBJECTIVE: We investigated the regulation of adipose tissue gene expression during different phases of a dietary weight loss program and its relation with insulin sensitivity. RESEARCH DESIGN AND METHODS: Twenty-two obese women followed a dietary intervention program composed of an energy restriction phase with a 4-week very-low-calorie diet and a weight stabilization period composed of a 2-month low-calorie diet followed by 3-4 months of a weight maintenance diet. At each time point, a euglycemic-hyperinsulinemic clamp and subcutaneous adipose tissue biopsies were performed. Adipose tissue gene expression profiling was performed using a DNA microarray in a subgroup of eight women. RT-quantitative PCR was used for determination of mRNA levels of 31 adipose tissue macrophage markers (n = 22). RESULTS: Body weight, fat mass, and C-reactive protein level decreased and glucose disposal rate increased during the dietary intervention program. Transcriptome profiling revealed two main patterns of variations. The first involved 464 mostly adipocyte genes involved in metabolism that were downregulated during energy restriction, upregulated during weight stabilization, and unchanged during the dietary intervention. The second comprised 511 mainly macrophage genes involved in inflammatory pathways that were not changed or upregulated during energy restriction and downregulated during weight stabilization and dietary intervention. Accordingly, macrophage markers were upregulated during energy restriction and downregulated during weight stabilization and dietary intervention. The increase in glucose disposal rates in each dietary phase was associated with variation in expression of sets of 80-110 genes that differed among energy restriction, weight stabilization, and dietary intervention. CONCLUSIONS: Adipose tissue macrophages and adipocytes show distinct patterns of gene regulation and association with insulin sensitivity during the various phases of a dietary weight loss program

The information and orientation system of school building

Import 03/08/2012Bakalářská práce na téma „Informační a orientační systém školské budovy“ se zaměřuje na orientační, informační a bezpečnostní systém ve školní budově. Tato práce byla aplikována na ZŠ Hornickou v Hlučíně. Práce se zaměřuje na tyto části: V první části se zaobírám otázkou, co vše patří do informačního a orientačního systému. Konkrétně rozdělením těchto systémů umístěných v exteriéru a interiéru. V druhé části jsou řešeny zásady pro správný návrh systému, jako je písmo, barva, jednoduchost, přehlednost, a umístění. Třetí část je zaměřena na podrobný popis návrhu vnitřního informačního systému na ZŠ Hornická. Návrh obsahuje centrální tabuli, exteriérovou tabuli, patrovou orientační tabuli, popisové kancelářské cedulky, piktogramy, čísla místností a evakuační tabulky. Ve čtvrté části je navrženo možné bezbariérové řešení na ZŠ. Cílem bakalářské práce bylo vytvořit jednoduchý a přehledný informační a orientační systém s bezbariérovým přístupem na ZŠ Hornické v Hlučíně.The following bachelor thesis called “Information and orientation system of a school building“ focuses on orientation, information and security system in a certain school building. This research has been applied to the primary mining school in Hlučín. The first part of this work deals with everything that comes under information and orientation system located both in exterior and interior of the building. The second part focuses on instructions given for an accurate design of the system such as writing fonts, colour, simplicity, correct arrangement and placement. The third part contains detailed description of the design of an interior information system in the mentionned primary school. This design includes central board, exterior board, orientation board for each floor, instructive office signs, pictograms, room numbers and evacuation boards. A wheelchair accessible system is then suggested in the fourth part. The main aim of the bachelor thesis was to design a simple but instructive information and orientation system with a wheelchair access in the primary mining school in Hlučín.Prezenční222 - Katedra městského inženýrstvívýborn

Regulation of human adipose tissue gene expression in relation to obesity and insulin resistance

Obesity is associated with insulin resistance (IR) and type 2 diabetes mellitus. Among possible mechanisms leading to IR are increased plasma levels of free fatty acids and Alfred levels of adipokines secreted from adipose tissue (AT). In the first part of the work, we studied obese patients during different nutritional and physical activity interventions. Phenotypic data were related to the expression of AT genes potentially involved in the regulation of insulin sensitivity (IS) and/or low-grade inflammation. We confirmed that aerobic and dynamic strength training improved IS and demonstrated that these interventions do not promote changes in subcutaneous AT gene expression or in plasma levels of adiponectin, interleukin-6, interleukin-1 beta and tumor necrosis factor-alpha, but decrease circulating leptin level. Very low calorie diet followed by low calorie diet and weight maintenance period enhanced IS in obese women and diminished retinol-binding protein 4 (RBP4) in plasma, but RBP4 mRNA levels were reduced only after very low calorie diet. Our findings indicate that the investigated adipokines, except potentially leptin, might not be mediators of changes in IS induced by lifestyle interventions. In the second part of the work, we investigated the role of peroxisome proliferator-activated receptors..

Regulace lidské tukové tkáni exprese genu ve vztahu k obezitě a inzulínové rezistence

Katedra genetiky a mikrobiologieDepartment of Genetics and MicrobiologyFaculty of SciencePřírodovědecká fakult