188 research outputs found

    Controllers design for plants with small time constants

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    Tato bakaláƙskĂĄ prĂĄce se zabĂœvĂĄ nĂĄvrhem a nastavenĂ­m spojitĂœch regulĂĄtorĆŻ pro regulovanĂ© soustavy s malĂœmi časovĂœmi konstantami. Byly navrĆŸeny regulovanĂ© obvody s rĆŻznĂœmi typy regulĂĄtorĆŻ a s rĆŻznĂœm nastavenĂ­m jejich parametrĆŻ. NastavenĂ­ parametrĆŻ bylo provedeno pomocĂ­ metod syntĂ©zy regulačnĂ­ho obvodu. Tyto vypočtenĂ© parametry byly porovnĂĄny a vyhodnoceny z hlediska pƙesnosti a kvality regulace.The main reason of this project is to set up and to propose continous controllers for process with small time responses. The regulated circuits with different type of regulators and its different settings were proposed in this project. These parameters were set up with method synthesis. These calculation were compared and evaculated as regards to control accurancy and quality.

    Synchronization of economic cycles in countries of the Visegrad Group, Germany and Eurozone

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    Most countries of the Visegrad group presently undertake meticulous preparation for entry to the Eurozone, which makes the issue of business cycle synchronization contemporary. In this study, we identified business cycle in V4 member states, Germany and the Eurozone and investigated the degree of business cycle synchronization among V4 countries, with Germany and the Eurozone. Quarterly GDP data, season and calendar adjusted from 1995: 1 through 2016: 4 (T = 88) were broken down to trend and cyclical elements by the Hodrick-Prescott filter and used to obtain the relative output gap. Phases of the business cycle were identified through modified BBQ algorithm. Business cycle synchronization was quantified with Pearson correlation coefficient, concordance index and Mink similarity index calculated separately for time segments before EU accession in 2004 and after. Tests of statistical significance were carried out, where relevant. In the period before EU enlargement, few economic cycles were correlated weakly, but many were not synchronized at all or were even negatively correlated. After EU accession, the cycles became closely synchronized among V4 countries or between V4 state and Germany or Eurozone. Although the degree of correlation between V4 countries and Eurozone is not as strong, as for Germany and Eurozone, it is obvious that V4 countries are becoming increasingly prepared for adopting Euro, as their currency, with respect to the requisite of economic cycle synchronization.O

    The Effect of Fiscal Policy Asymmetries on Business Cycle Correlation in the EU

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    This paper reviews the role of bilateral fiscal differences, fiscal indiscipline and their joint effects in particular in determining business cycle synchronicity in the European Union (EU). Panel data comprising 28 EU members from 1999–2019 are used in the analysis. The two-step Instrumental Variable–Generalized Method of Moments (IV–GMM) is employed to estimate the effects of examined fiscal measures on business cycle correlations. The study finds that fiscal indiscipline doubles the negative effect of increasing fiscal differences on business cycle correlation compared to fiscally disciplined country-pairs. The findings suggest reopening the debate on fiscal policy coordination across Europe

    Expression of S100A8 correlates with inflammatory lung disease in congenic mice deficient of the cystic fibrosis transmembrane conductance regulator

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    BACKGROUND: Lung disease in cystic fibrosis (CF) patients is dominated by chronic inflammation with an early and inappropriate influx of neutrophils causing airway destruction. Congenic C57BL/6 CF mice develop lung inflammatory disease similar to that of patients. In contrast, lungs of congenic BALB/c CF mice remain unaffected. The basis of the neutrophil influx to the airways of CF patients and C57BL/6 mice, and its precipitating factor(s) (spontaneous or infection induced) remains unclear. METHODS: The lungs of 20-day old congenic C57BL/6 (before any overt signs of inflammation) and BALB/c CF mouse lines maintained in sterile environments were investigated for distinctions in the neutrophil chemokines S100A8 and S100A9 by quantitative RT-PCR and RNA in situ hybridization, that were then correlated to neutrophil numbers. RESULTS: The lungs of C57BL/6 CF mice had spontaneous and significant elevation of both neutrophil chemokines S100A8 and S100A9 and a corresponding increase in neutrophils, in the absence of detectable pathogens. In contrast, BALB/c CF mouse lungs maintained under identical conditions, had similar elevations of S100A9 expression and resident neutrophil numbers, but diverged in having normal levels of S100A8. CONCLUSION: The results indicate early and spontaneous lung inflammation in CF mice, whose progression corresponds to increased expression of both S100A8 and S100A9, but not S100A9 alone. Moreover, since both C57BL/6 and BALB/c CF lungs were maintained under identical conditions and had similar elevations in S100A9 and neutrophils, the higher S100A8 expression in the former (or suppression in latter) is a result of secondary genetic influences rather than environment or differential infection

    Intra-amniotic delivery of CFTR-expressing adenovirus does not reverse cystic fibrosis phenotype in inbred CFTR-knockout mice

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    This article is available open access through the publisher’s website at the link below. Copyright © 2008 The American Society of Gene Therapy.Due to its early onset and severe prognosis, cystic fibrosis (CF) has been suggested as a candidate disease for in utero gene therapy. In 1997, a study was published claiming that to how transient prenatal expression of CF transmembrane conductance regulator (CFTR) from an in utero –injected adenovirus vector could achieve permanent reversal of the CF intestinal pathology in adult CF knockout mice, despite the loss of CFTR transgene expression by birth. This would imply that the underlying cause of CF is a prenatal defect for which lifelong cure can be achieved by transient prenatal expression of CFTR. Despite criticism at the time of publication, no independent verification of this contentious finding has been published so far. This is vital for the development of future therapeutic strategies as it may determine whether CF gene therapy should be performed prenatally or postnatally. We therefore reinvestigated this finding with an identical adenoviral vector and a knockout CF mouse line (CftrtmlCam) with a completely inbred genetic background to eliminate any effects due to genetic variation. After delivery of the CFTR-expressing adenovirus to the fetal mouse, both vector DNA and transgenic CFTR expression were detected in treated animals postpartum but statistically no significant difference in survival was observed between the Cftr–/– mice treated with the CFTR-adenovirus and those treated with the control vector.Sport Aiding Medical Research for Kids, the Cystic Fibrosis Trust, and the Katharine Dormandy Trust

    Cystic Fibrosis, Atopy, Asthma and ABPA

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    The role of atopy on cystic fibrosis (CF) progression remains unclear but evidence suggests that it may influence the appearance of co-morbid conditions such as CF asthma or allergic bronchopulmonary aspergillosis (ABPA). Recognising asthma in patients with CF is not always easy but the identification of atopic markers favours the diagnosis. Physicians should be aware of this fact in order to achieve a better control of respiratory symptoms in patients with CF. Bronchial mucosa inflammation and abnormal mucus predispose to mould colonisation. These patients are at higher risk of allergic sensitisation, especially when atopic susceptibility is present. In the particular case of A. fumigatus, allergic sensitisation precedes ABPA development, which occurs in up to 10% of CF patients. Progression of lung function deterioration is most strikingly pronounced in patients with ABPA. Therefore, sensitisation with A. fumigatus should be regularly tested in patients with CF, especially those at higher risk. Recombinant allergens constitute an important advance in differentiating Aspergillus sensitisation from ABPA itself

    CLC-2 single nucleotide polymorphisms (SNPs) as potential modifiers of cystic fibrosis disease severity

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    BACKGROUND: Cystic fibrosis (CF) lung disease manifest by impaired chloride secretion leads to eventual respiratory failure. Candidate genes that may modify CF lung disease severity include alternative chloride channels. The objectives of this study are to identify single nucleotide polymorphisms (SNPs) in the airway epithelial chloride channel, CLC-2, and correlate these polymorphisms with CF lung disease. METHODS: The CLC-2 promoter, intron 1 and exon 20 were examined for SNPs in adult CF dF508/dF508 homozygotes with mild and severe lung disease (forced expiratory volume at one second (FEV1) > 70% and < 40%). RESULTS: PCR amplification of genomic CLC-2 and sequence analysis revealed 1 polymorphism in the hClC -2 promoter, 4 in intron 1, and none in exon 20. Fisher's analysis within this data set, did not demonstrate a significant relationship between the severity of lung disease and SNPs in the CLC-2 gene. CONCLUSIONS: CLC-2 is not a key modifier gene of CF lung phenotype. Further studies evaluating other phenotypes associated with CF may be useful in the future to assess the ability of CLC-2 to modify CF disease severity

    DHA Supplemented in Peptamen Diet Offers No Advantage in Pathways to Amyloidosis: Is It Time to Evaluate Composite Lipid Diet?

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    Numerous reports have documented the beneficial effects of dietary docosahexaenoic acid (DHA) on beta-amyloid production and Alzheimer's disease (AD). However, none of these studies have examined and compared DHA, in combination with other dietary nutrients, for its effects on plaque pathogenesis. Potential interactions of DHA with other dietary nutrients and fatty acids are conventionally ignored. Here we investigated DHA with two dietary regimes; peptamen (pep+DHA) and low fat diet (low fat+DHA). Peptamen base liquid diet is a standard sole-source nutrition for patients with gastrointestinal dysfunction. Here we demonstrate that a robust AD transgenic mouse model shows an increased tendency to produce beta-amyloid peptides and amyloid plaques when fed a pep+DHA diet. The increase in beta-amyloid peptides was due to an elevated trend in the levels of beta-secretase amyloid precursor protein (APP) cleaving enzyme (BACE), the proteolytic C-terminal fragment beta of APP and reduced levels of insulin degrading enzyme that endoproteolyse beta-amyloid. On the contrary, TgCRND8 mice on low fat+DHA diet (based on an approximately 18% reduction of fat intake) ameliorate the production of abeta peptides and consequently amyloid plaques. Our work not only demonstrates that DHA when taken with peptamen may have a tendency to confer a detrimental affect on the amyloid plaque build up but also reinforces the importance of studying composite lipids or nutrients rather than single lipids or nutrients for their effects on pathways important to plaque development

    Intestinal Obstruction Syndromes in Cystic Fibrosis: Meconium Ileus, Distal Intestinal Obstruction Syndrome, and Constipation

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    Meconium ileus at birth, distal intestinal obstruction syndrome (DIOS), and constipation are an interrelated group of intestinal obstruction syndromes with a variable severity of obstruction that occurs in cystic fibrosis patients. Long-term follow-up studies show that today meconium ileus is not a risk factor for impaired nutritional status, pulmonary function, or survival. DIOS and constipation are frequently seen in cystic fibrosis patients, especially later in life; genetic, dietary, and other associations have been explored. Diagnosis of DIOS is based on suggestive symptoms, with a right lower quadrant mass confirmed on abdominal radiography, whereas symptoms of constipation are milder and of longer standing. In DIOS, early aggressive laxative treatment with oral laxatives (polyethylene glycol) or intestinal lavage with balanced osmotic electrolyte solution and rehydration is required, which now makes the need for surgical interventions rare. Constipation can generally be well controlled with polyethylene glycol maintenance treatment
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