26 research outputs found

    Machining of Aluminum Alloy

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    Import 23/07/2015Diplomová práce se zabývá kvalitou opracované hliníkové slitiny EN AW-6082, speciálně drsností povrchu a měřením a vyhodnocením složek řezných sil. Teoretická část objasňuje základní pojmy věnované čelnímu frézování, obrobitelnosti hliníku, obráběným materiálům, řezným podmínkám a geometrii obrábění. V návrhu experimentální části práce je popsáno použití stroje, nástroje a vyměnitelných břitových destiček, přístrojů na měření drsnosti, velikosti řezných sil a navržené řezné podmínky. V experimentální části práce jsou změřeny drsnosti povrchu a presentovány výsledky naměřených hodnot drsnosti Ra a Rz. Řezné síly byly měřeny na piezoelektrickém dynamometru.This master thesis is concerned with the quality of machined aluminium alloy EN AW-6082, especially surface roughness and the measurement and evaluation components of the cutting forces. The theoretical part explains the basic concepts of frontal milling, machinability aluminium, machined material, cutting conditions and geometry processing. In the proposal of the experimental part is described the using of machine, tool and indexable inserts, devices for measuring roughness, cutting forces and proposed cutting conditions. In the experimental part of the work are measured surface roughnesses and presented the results of the measured values of roughness Ra and Rz. Cutting forces were measured on the piezoelectric dynamometer.346 - Katedra obrábění, montáže a strojírenské metrologievelmi dobř

    Multivariable Analysis Evaluating the Association between GDF-15 and Echocardiographic variables in hypertensive patients.

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    <p>Multivariate general linear was performed, adjusted by traditional covariates age, sex, BMI, SBP, DBP, TC, LDL-C, HDL-C, TG, eGFR and glucose in hypertensive patients with LVH. IVS, inter-ventricular septum; PWT, left ventricular posterior wall; EDD, end-diastolic diameter; ESD, end-systolic diameter; LVMI, left ventricular mass index. β standardized coefficients were recorded for each outcome variable. The difference is significant at P<0.05.</p

    Plasma GDF-15 levels in hypertensive patient with or without LVH.

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    <p>The GDF-15 levels are presented as box (median, 25th percentile, 75th percentile) and whisker (5th and 95th percentiles) plots. P<0.001 by the Wilcoxon two-sample test in panels. GDF-15, growth differentiation factor; LVH, left ventricular hypertrophy.</p

    Determinants and Time Trends for Ischaemic and Haemorrhagic Stroke in a Large Chinese Population

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    <div><p>Background</p><p>The clinical epidemiology of stroke has been widely investigated in Caucasian populations, but the changes over time in the proportion of ischaemic to haemorrhagic strokes is less clear, especially in the Chinese population.</p><p>Aims</p><p>Our objective was to study the determinants and time trends for ischaemic and haemorrhagic stroke, in relation to age, in a large Chinese population cohort.</p><p>Methods</p><p>Using a medical insurance database in the southwest of China from 2001 to 2012, time trends in age-adjusted ischaemic and haemorrhagic stroke incidence and the contributing risk factors associated with age were investigated.</p><p>Results</p><p>Among 425,901 individuals without prior stroke (52.4% male, median age 54), the rate of ischaemic stroke (per 1000 patient-years) decreased between 2002–2007, then remained broadly similar between 2008–2012. The rate of haemorrhagic stroke showed a similar trend, being approximately 1.3–1.9 from 2008–2012. Compared to patients age<65, ischaemic and haemorrhagic stroke incidences (rate, 95% confidential interval, CI) were higher in the elderly population (age <65 versus age ≥65: ischaemic: 3.64, 3.33–4.00, vs 14.33, 14.01–14.60; haemorrhagic: 1.09, 1.00–1.10 vs 2.52,2.40–2.70, respectively, both p<0.001). There were no significant differences in haemorrhagic stroke rates between the elderly and the very elderly population. Ischaemic and haemorrhagic stroke shared similar risk factors (age, hypertension, coronary artery disease (CAD), vascular disease, and diabetes mellitus) (all p<0.05). In subjects age<75 years, CAD (7.17, 4.14–12.37) and diabetes mellitus (3.27, 2.42–4.42) contributed most to the developing of haemorrhagic stroke (all p<0.001). Amongst the very elderly, vascular disease (2.24, 1.49–3.37) was an additional major risk factor for haemorrhagic stroke, together with CAD and diabetes mellitus (all p<0.001).</p><p>Conclusion</p><p>In this large Chinese cohort, there was an increased risk of ischaemic stroke compared to haemorrhagic stroke with ageing. CAD, vascular disease, diabetes mellitus, and hypertension were major contributors to the development of hemorrhagic stroke in the very elderly Chinese population.</p></div

    Frequency of FoxO1 and FoxO3 polymorphism in CHD from two different populations.

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    <p>Calculations are performed with comparison of three different genotypes. Values are the number of subjects. No significant difference (chi-square test) was found in the frequency of either polymorphism between CHD cases and non-CHD controls.</p

    Association Study to Evaluate FoxO1 and FoxO3 Gene in CHD in Han Chinese

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    <div><p>Background</p><p>Coronary heart disease (CHD) is one of the leading causes of mortality and morbidity in China. Genetic factors that predispose individuals to CHD are unclear. In the present study, we aimed to determine whether the variation of FoxOs, a novel genetic factor associated with longevity, was associated with CHD in Han Chinese populations.</p><p>Methods</p><p>1271 CHD patients and 1287 age-and sex-matched controls from Beijing and Harbin were included. We selected four tagging single nucleotide polymorphisms (SNPs) of FoxO1 (rs2755209, rs2721072, rs4325427 and rs17592371) and two tagging SNPs of FoxO3 (rs768023 and rs1268165). And the genotypes of these SNPs were determined in both CHD patients and non-CHD controls.</p><p>Results</p><p>For population from Beijing, four SNPs of FoxO1 and two SNPs of FoxO3 were found not to be associated with CHD (p>0.05). And this was validated in the other population from Harbin (p>0.05). After combining the two geographically isolated case-control populations, the results showed that the six SNPs did not necessarily predispose to CHD in Han Chinese(p>0.05). In stratified analysis according to gender, the history of smoking, hypertension, diabetes mellitus, hyperlipidemia and the metabolic syndrome, we further explored that neither the variants of FoxO1 nor the variants of FoxO3 might be associated with CHD (p>0.05).</p><p>Conclusion</p><p>The variants of FoxO1 and FoxO3 may not increase the prevalence of CHD in Han Chinese population.</p></div

    Multivariate analysis of risk factors for ischaemic and haemorrhagic stroke associated with age strata amongst 425,901 Chinese subjects.

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    <p>Multivariate analysis of risk factors for ischaemic and haemorrhagic stroke associated with age strata amongst 425,901 Chinese subjects.</p
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