Influence of Geometry on Cutting Tool Durability

Import 23/08/2017Bakalářská práce se zabývá porovnáním rozdílných geometrií frézovacích nástrojů v podmínkách společnosti Pramet Tools s.r.o. V úvodu je popsána obecná charakteristika rovinného a kopírovacího frézování spolu s charakteristikou geometrie nástroje a popisu trvanlivosti a opotřebení břitu nástroje. V další části této práce je popsána příprava a provedení experimentálních zkoušek nástrojů, konkrétně se jedná o funkční zkoušky obrábění a zkoušky trvanlivosti. Poslední část práce je zaměřena na shrnutí a vyhodnocení naměřených hodnot jednotlivých zkoušek, na základě kterých je stanoven závěr práce.The aim of this bachelor thesis is to compares different geometries of machining milling tools in conditions set by Pramet Tools s.r.o. company. The introduction part describes general charakteristics of planar and profille milling, tool geometry, durability and wear endurance. Next part of the thesis describes test preparation, machining characterization and durability trials. The aim of the last part is summary of all results, post processing and conclusion of the bachelor thesis.346 - Katedra obrábění, montáže a strojírenské metrologievýborn

Effect of Cutting Speed on Accuracy and Surface Roughness during Multi-Axis Milling

Tato diplomová práce pojednává o vlivu efektivní řezné rychlosti na kvalitu a drsnost obrobeného povrchu technologií víceosého frézování. Hlavním cílem práce je analýza drsnosti povrchů experimentálních vzorků vyrobených metodou 3osého frézování a metodou 5osého frézování, kde je porovnáváno několik skupin naklonění osy nástroje. V teoretické části je zmíněn technický rozbor 3osého a víceosého frézování spolu s popisem vztahů efektivních řezných průměrů a efektivní řezné rychlosti na změně náklonu nástroje, charakteristika profilové drsnosti povrchu a charakteristika plošného hodnocení textury povrchu. V další části práce je popsána příprava a provedení experimentálního měření vzorků s vyhodnocením naměřených dat, na základě kterých je stanoven závěr práce.This master thesis deals with influence of the effective cuting speed on quality, texture and roughness of the multi-axis milling machined surface. The main goal of the work is to analyze the surface roughness of experimental samples produced by the 3-axis and 5-axis milling process, where several tool tilt angles are compared. In the theoretical part is mentioned the technical analysis of 3-axis and multi-axis milling together with the description of the effective cutting diameter relationship and the effective speed cutting on the tool tilt geometry change, the surface roughness profile and the characteristic of the surface texture. The next part of the thesis describes the preparation and execution of an experimental measurement of the sample with the evalution of the measured data, based on which the conclusion of the work is determined.346 - Katedra obrábění, montáže a strojírenské metrologievýborn

Pentraxin 3(PTX 3): An Endogenous Modulator of the Inflammatory Response

Inflammatory or anti-inflammatory? That is the question as far as the acute-phase response and its mediators, the pentraxins, are concerned. Only some ten years ago, the classical or short pentraxin C-reactive protein and the newly discovered long pentraxin PTX3 were considered to exert most of the detrimental effects of acute inflammation, whether microbial or sterile in origin. However, accumulating evidence suggests an at least dichotomous, context-dependent outcome attributable to the pentraxins, if not a straightforward anti-inflammatory nature of the acute-phase response. This paper is focused on the inherent effects of pentraxin 3 in inflammatory responses, mainly in coronary artery disease and in Aspergillus fumigatus infection. Both are examples of inflammatory reactions in which PTX3 is substantially involved; the former sterile, the latter infectious in origin. Apart from different inducing noxae, similarities in the pathogenesis of the two are striking. All the same, the introductory question still persists: is the ultimate impact of PTX3 in these conditions inflammatory or anti-inflammatory, paradoxical as the latter might appear? We try to provide an answer such as it emerges in the light of recent findings

The Effect of Conventional and Mini-Invasive Cardiopulmonary Bypass on Neutrophil Activation in Patients Undergoing Coronary Artery Bypass Grafting

Interleukin-10 (IL-10) is considered to be a cytokine with potent anti-inflammatory properties, which have been previously linked to increased incidence of sepsis. The level of IL-10 is elevated by cardiac surgery when cardiopulmonary bypass (CPB) and methylprednisolone are used. In our study, we compare the level of IL-10, IL-10 Receptor (IL-10R), and percentage of neutrophils between two groups of cardiac surgical patients undergoing Coronary Artery Bypass Grafting, both of which were not given methylprednisolone. The first group was operated with conventional CPB, while the second group was operated with minimally invasive CPB (mini-CPB). We detected enhanced level of IL-10 during surgery and at the end of surgery in both groups of patients. While no correlation between IL-10 and IL10R was found, IL-10 was positively correlated with increased percentage of neutrophils at the time points when the level of IL-10 peaked

Lipopolysaccharide Binding Protein and sCD14 are Not Produced as Acute Phase Proteins in Cardiac Surgery

Objectives. The changes in the serum levels of lipopolysaccharide binding protein (LBP) and sCD14 during cardiac surgery were followed in this study. Design. Thirty-four patients, 17 in each group, were randomly assigned to coronary artery bypass grafting surgery performed either with (“on-pump”) or without (“off-pump”) cardiopulmonary bypass. LBP and sCD14 were evaluated by ELISA. Results. The serum levels of LBP were gradually increased from the 1st postoperative day and reached their maximum on the 3rd postoperative day in both “on-pump” and “off-pump” patients (30.33±9.96 μg/mL; 37.99±16.58 μg/mL), respectively. There were no significant differences between “on-pump” and “off-pump” patients regarding LBP. The significantly increased levels of sCD14 from the 1st up to the 7th postoperative day in both “on-pump” and “off-pump” patients were found with no significant differences between these groups. No correlations between LBP and sCD14 and IL-6, CRP and long pentraxin PTX3 levels were found. Conclusions. The levels of LBP and sCD14 are elevated in cardiac surgical patients being similar in both groups. These molecules are not produced as acute phase proteins in these patients

Early Expression of FcγRI (CD64) on Monocytes of Cardiac Surgical Patients and Higher Density of Monocyte Anti-Inflammatory Scavenger CD163 Receptor in “On-Pump” Patients

Objective. Activation of innate immunity cells is inseparably linked to cardiac surgical operation. The aim of this study was to assess the kinetics in the expression of receptor for Fc part of IgG, FcγRI (CD64), and scavenger receptor CD163 on peripheral blood cells of cardiac surgical patients and to examine the effect of cardiac bypass as a separable influence on the systemic acute inflammatory response. Methods. Forty patients, twenty in each group, were randomly assigned to CABG surgery performed either with “on-pump” or without “off-pump” cardiopulmonary bypass. Standardized quantitative flow cytometry method was used to determine the expression of surface markers. Results. The density of CD64 molecule on monocytes reached maximum on the 1st postoperative day (P<.001) whereas the peak for CD64 molecule expression on granulocytes was postponed to the 3rd postoperative day (P<.001). The expression of CD163 scavenger molecule on monocytes reached maximum on the 1st postoperative day (P<.001). The density of CD163 molecule on monocytes on the 1st postoperative day is significantly higher in “on-pump” patients in comparison with “off-pump” patients (P<.001). Conclusion. In cardiac surgical patients the expression of activation marker FcγR1 (CD64) on monocytes is increased earlier in comparison with granulocytes in both “on-pump” and “off-pump” patients. The expression of scavenger molecule CD163 on monocytes is significantly higher in “on-pump” patients

TLR2 in Pleural Fluid Is Modulated by Talc Particles during Pleurodesis

The aim of this study was to examine the role of TLR2 molecule in pleural space during thoracoscopic talc pleurodesis period in patients with malignant pleural effusion. We analyzed TLR2 molecule in soluble form as well as on membrane of granulocytes in pleural fluid. Pleural fluid examination was done at three intervals during pleurodesis procedure: 1st—before the thoracoscopic procedure, 2nd—2 hours after the terminating thoracoscopic procedure with talc insufflation, 3rd—24 hours after the thoracoscopic procedure. We reported significant increase of soluble TLR2 molecule in pleural fluid effusion during talc pleurodesis from preoperative value. This increase was approximately 8-fold in the interval of 24 hours. The changes on granulocyte population were quite different. The mean fluorescent intensity of membrane TLR2 molecule examined by flow cytometry on granulocyte population significantly decreased after talc exposure with comparison to prethoracoscopic density. To estimate the prognostic value of TLR2 expression in pleural fluid patients were retrospectively classified into either prognostically favourable or unfavourable groups. Our results proved that patients with favourable prognosis had more than 3-fold higher soluble TLR2 level in pleural fluid early, 2 hours after talc pleurodesis intervention

Oxidative Damage to Nucleic Acids and Benzo(a)pyrene-7,8-diol-9,10-epoxide-DNA Adducts and Chromosomal Aberration in Children with Psoriasis Repeatedly Exposed to Crude Coal Tar Ointment and UV Radiation

The paper presents a prospective cohort study. Observed group was formed of children with plaque psoriasis (n = 19) treated by Goeckerman therapy (GT). The study describes adverse (side) effects associated with application of GT (combined exposure of 3% crude coal tar ointment and UV radiation). After GT we found significantly increased markers of oxidative stress (8-hydroxy-2 -deoxyguanosine, 8-hydroxyguanosine, and 8-hydroxyguanine), significantly increased levels of benzo[a]pyrene-7,8-diol-9,10-epoxide (BPDE) DNA adducts (BPDE-DNA), and significantly increased levels of total number of chromosomal aberrations in peripheral lymphocytes. We found significant relationship between (1) time of UV exposure and total number of aberrated cells and (2) daily topical application of 3% crude coal tar ointment (% of body surface) and level of BPDE-DNA adducts. The findings indicated increased hazard of oxidative stress and genotoxic effects related to the treatment. However, it must be noted that the oxidized guanine species and BPDE-DNA adducts also reflect individual variations in metabolic enzyme activity (different extent of bioactivation of benzo[a]pyrene to BPDE) and overall efficiency of DNA/RNA repair system. The study confirmed good effectiveness of the GT (significantly decreased PASI score)

Clinical Study Selected Inflammatory and Metabolic Markers in Psoriatic Patients Treated with Goeckerman Therapy

Psoriasis is associated with metabolic activity of adipose tissue which produces pro-and anti-inflammatory adipokines. Goeckerman therapy (GT) represents an effective treatment of psoriasis. This study evaluated variation of selected inflammatory and metabolic markers during GT and the relationships between the markers, severity of the disease (PASI score), body mass, and the basic characteristics of the therapy. The study was conducted on a group of patients ( = 32) and on a control group ( = 24). Before GT, we found significantly elevated levels of proinflammatory CRP ( &lt; 0.001) and leptin ( &lt; 0.05) in psoriatic patients (compared to the controls). The therapy significantly decreased the levels of CRP and adiponectin. We found positive correlations between CRP and total duration of GT ( &lt; 0.05) and CRP and the time of UV exposure ( &lt; 0.01) and negative correlations between adiponectin and the total duration of GT ( &lt; 0.05) and adiponectin and the application of CCT ointment ( &lt; 0.001). From our results, we can conclude that GT causes partial reduction of both proinflammatory and anti-inflammatory markers. However, the levels of proinflammatory CRP and leptin remained significantly higher in the patients than in the control group

Vitamin D as an Adjunctive Therapy in Asthma. Part 1: A Review of Potential Mechanisms

Vitamin D deficiency (VDD) is highly prevalent worldwide. The classical role for vitamin D is to regulate calcium absorption form the gastrointestinal tract and influence bone health. Recently vitamin D receptors and vitamin D metabolic enzymes have been discovered in numerous sites systemically supporting diverse extra-skeletal roles of vitamin D, for example in asthmatic disease. Further, VDD and asthma share several common risk factors including high latitude, winter season, industrialization, poor diet, obesity, and dark skin pigmentation. Vitamin D has been demonstrated to possess potent immunomodulatory effects, including effects on T cells and B cells as well as increasing production of antimicrobial peptides (e.g. cathelicidin). This immunomodulation may lead to asthma specific clinical benefits in terms of decreased bacterial/viral infections, altered airway smooth muscle-remodeling and efunction as well as modulation of response to standard anti-asthma therapy (e.g. glucocorticoids and immunotherapy). Thus, vitamin D and its deficiency have a number of biological effects that are potentially important in altering the course of disease pathogenesis and severity in asthma. The purpose of this first of a two-part review is to review potential mechanisms whereby altering vitamin D status may influence asthmatic disease