159 research outputs found

    Global behavior of a fourth order difference equation

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    We determine the forbidden set, introduce an explicit formula for the solutions, and discuss the global behavior of solutions of a fourth order difference equation

    Functional Analysis of Heat Shock Protein HSPA4

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    Die Ziele dieser Arbeit waren, die GrĂŒnde fĂŒr die mĂ€nnliche InfertilitĂ€t, das verringerte GrĂ¶ĂŸenwachstum und die kardiale Hypertrophie, die in Hspa4-/- MĂ€usen vorliegen, zu untersuchen.Um das spermatogoniale Stadium zu identifizieren, in dem die Spermatogenese in Hspa4-defizienten MĂ€usen mit C57BL/6J x 129/Sv hybridem genetischem Hintergrund betroffen ist, fĂŒhrten wir histologische und immunologische Analysen durch. Untersuchungen der Keimzellentwicklung in juvenilen Hspa4-/- MĂ€usen zeigten einen Arrest der ersten Spermatogenesewelle in der spĂ€ten Prophase I. Auf RNA-Ebene konnte eine deutliche Verminderung der Expression spĂ€ter meiotischer und postmeiotischer Markergene detektiert werden, wohingegen die Expression frĂŒher meiotischer Gene in Hspa4-/- Testes nicht verĂ€ndert war. Diese Ergebnisse lassen vermuten, dass HSPA4 fĂŒr die Regulierung diverser Chaperon-vermittelter Prozesse und des Zellzyklus wĂ€hrend der Keimzellentwicklung benötigt wird.Das zweite Ziel dieser Arbeit war es, den Grund fĂŒr das verringerte GrĂ¶ĂŸenwachstum in Hspa4-defizienten MĂ€usen im inbred 129/Sv genetischen Hintergrund zu untersuchen. Um herauszufinden, ob das verringerte GrĂ¶ĂŸenwachstum an einer Myopathie der Skelettmuskeln liegt, wurden verschiedene histologische Analysen verschiedener Skelettmuskeln durchgefĂŒhrt. Diese Analysen zeigten, dass die Muskeln Tibialis anterior, Vastus intermedius, Soleus und die paraspinale Muskulatur in adulten Hspa4-/- MĂ€usen myopathische VerĂ€nderungen aufwiesen. DarĂŒber hinaus konnte gezeigt werden, dass diese myopathischen VerĂ€nderungen bereits im frĂŒhen postnatalen Entwicklungsstadium der Hspa4-/- MĂ€use vorlagen. Dies ließ vermuten, dass die Myopathie der Skelettmuskeln der Grund fĂŒr das verringerte GrĂ¶ĂŸenwachstum ist. Außerdem lassen diese Ergebnisse vermuten, dass HSPA4 einen Effekt ausĂŒbt, der die Skelettmuskulatur vor mechanischem oder metabolischem Stress schĂŒtzt, der sonst die Degradierung der Skel! ettmuskulatur auslöst.Um herauszufinden, ob diese Myopathie der Skelettmuskulatur auch im Herzen als hypertrophe Kardiomyopathie vorliegt, wurden histologische Analysen und zwei-dimensionale Echokardiogramme durchgefĂŒhrt. Die histologischen Analysen zeigten die Entwicklung der kardialen Hypertrophie und von Fibrose im Herzen der Hspa4-defizienten MĂ€use. Ultrastrukturanalysen zeigten einen Abbau der Myofibrillen in Kardiomyocyten und eine gesteigerte Annsammlung von Collagen (Fibrose) im Herzen der Hspa4-defizienten MĂ€use. Echokardiogramme bestĂ€tigten die kardiale Hypertrophie bei Hspa4-/- MĂ€usen. Um herauszufinden, zu welchem Zeitpunkt die Entwicklung der kardialen Hypertrophie und der Fibrose in Hspa4-/- Herzen beginnt, wurde die Expression von Hypertrophie- und Fibrose-Markergenen im Herzen verschiedener postnataler Stadien mittels Northern Blot und RealTime-PCR untersucht. Diese Analysen zeigten, dass die Entwicklung der kardialen Hypertrophie und der Fibrose in Hspa4-/- MĂ€usen in frĂŒhen postnatalen Stadien beginnt. Wir vermuten, dass die frĂŒhe postnatale LetalitĂ€t bei Hspa4-/- MĂ€usen im inbred 129/SV genetischen Hintergrund durch das Fortschreiten der Myopathie der Skelettmuskulatur und die hypertrophe Kardiomyopathie erklĂ€rt werden kann. Im Gegensatz zum Skelettmuskel- und HerzphĂ€notyp bei Hspa4-/- MĂ€usen mit inbred Hintergrund zeigten histologische Untersuchungen und Expressionsanalysen hypertropher Gene, dass die kardiale Hypertrophie in Hspa4-defizienten MĂ€usen mit C57BL/6J x 129/Sv hybridem genetischem Hintergrund nicht ausgeprĂ€gt ist. Um die Signalwege zu identifizieren, die die kardiale Hypertrophie in Hspa4-/- MĂ€usen vermitteln, untersuchten wir in Herzen von Wildtyp-MĂ€usen und von Hspa4-/- MĂ€usen die Expression einiger Gene und Proteine, die am Gp130/STAT3-, MAPK- und Calcineurin-NFAT-Signalweg beteiligt sind. Diese Analysen ließen vermuten, dass die Stat3- und MAPK-Signalwege nicht fĂŒr die Entwicklung der kardialen Hypertrophie in Hspa4-/- MĂ€usen verantwortlich sind. Im Gegensatz dazu scheint eine erhöhte AktivitĂ€t des Calcineurin-NFAT-Signalwegs die kardiale Hypertrophie zu modulieren. Microarray-Analysen wurden verwendet, um die Genexpression im Herzen der Hspa4-defizienten MĂ€use im Alter von 25 Tagen mit denen von Wildtyp-MĂ€usen zu vergleichen. 98 Gene wurden identifiziert, die unterschiedlich exprimiert waren. Einige Gene wurden ausgewĂ€hlt und anhand ihrer Funktion in der Entwicklung der kardialen Hypertrophie klassifiziert. Um die Ergebnisse der Microarray-Analysen zu bestĂ€tigen, wurden quantitative RealTime-PCRs durchgefĂŒhrt. Wir konnten bestĂ€tigen, dass Gene, die in der Ionenkanal-vermittelten Signalweiterleitung (Kcne1, Kcnd2, Scn4a, Hcn1 and Irx4), im Schutz der Zellen vor oxidativem Stress (Gnao1, Ptp4a1 and Mme1) oder in der Induktion von oxidativem Stress (Maob) involviert sind, unterschiedlich exprimiert werden. Diese verĂ€nderte Expression kann an der Entwicklung der kardialen Hypertrophie in Hspa4-/- MĂ€usen beteiligt sein

    On the oscillation of a third order rational difference equation

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    AbstractIn this paper, we discuss the global asymptotic stability of all solutions of the difference equationxn+1=Axn-2B+Cxnxn-1xn-2,n=0,1,
where A,B,C are positive real numbers and the initial conditions x-2,x-1,x0 are real numbers. Although we have an explicit formula for the solutions of that equation, the oscillation character is worth to be discussed

    The Effect of Heat Treatment on Nanoparticle Size and ORRActivity for Carbon-supported Pd–Fe Alloy Electrocatalysts

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    The synthesized carbon-supported Pd-Fealloy electrocatalysts were characterized for the purpose of the fuel cell cathode oxygen reduction reaction (ORR). The synthesized catalysts were characterized in terms of structural morphology and catalytic activity by XRD and electrochemical measurements. Surface cyclic voltammetry was used to confirm the formation of the Pd–Fe alloy. The catalysts were heat-treated at temperatures ranging from 300 ◩C to 700 ◩C for different ageing times, in order to improve activity and stability. The average particle size of 10.16 nm, and the highest ORR catalytic activity were obtained at the optimal heat-treatment temperature 300 ◩C for 3h. Electrocatalytic ORR activity was also examined in an acidic solution containing methanol. The results showed that the synthesized Pd–Fe/C catalyst has methanol tolerant capabilities

    Assessment of the Elderly and Their Caregivers' Practices Regarding Food Safety in Assiut Governorate, Egypt

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    Food safety continues to be a concern of consumers and a focal point of the food industry and regulatory agencies. For over a century, developments in food production and new control philosophies have contributed to food safety systems in most developed countries to be efficient in the prevention of food borne diseases. The elderly are at particular risk of food borne illnesses because of their weaken immune systems, decrease in stomach acidity and intestinal peristalsis. The aim: to assess the practices of the elderly people and their caregivers about food safety. Setting: The present study was carried out at Assiut city (urban) and Assiut district (rural) in Assiut governorate. Design: descriptive cross sectional research design. The subjects were 10% of the total number of the elderly people from every area was selected randomly who aged 60 years and above and their caregivers involved in the study. The total number of the studied elderly was 720 (340 from urban and 380 from rural areas) and their caregivers (135 subjects). Results: nearly the total subject from the urban elderly (97.1%) and the majority of rural elderly (86.3%) did not know the temperature of the refrigerator, more than two fifths (44.7%) of the urban and more than one fifth (20.3%) of the rural elderly defrosting product in tape water. Conclusion: the elderly and their caregivers (urban and rural) were followed incorrect defrosting practices, incorrect hygiene of the kitchen counter, lack of knowledge regarding refrigeration temperature. Recommendations: the  information about food safety should be disseminated through mass media, television., newspapers and magazines at regular periods, establishment of an information center to help and guide the public especially mothers to maintain their practices regarding food safety. Key words: food safety, defrosting , kitchen counter

    New Polymer Syntheses Part: 55#. Novel Conducting Arylidene Polymers and Copolymers Based on Methyl-Cyclohexanone Moiety

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    A new interesting class of conducting polymers based on methyl-cyclohexanone in the polymer main chain has been synthesized by solution polycondensation of terephthalaldehyde with methyl-cyclohexanone. Copolymers containing different cycloalkanone moieties were also synthesized using solution polycondensation technique. The model compound I was synthesized by the interaction of methyl-cyclohexanone monomer with benzaldehyde, and its structure was confirmed by elemental and spectral analyses. The resulting new polymers and copolymers were characterized by elemental and spectral analyses, beside solubility and viscometry measurements. The thermal properties of those polymer and copolymers were evaluated by TGA, DrTGA and DTA measurements and correlated to their structural units. PDT as well as T10 was in the range from 205 to 370 ÂșC. In addition, T10 thermal stability for all the polymers was in theorder: VI> II > III > IV > V. X–ray analysis showed that it has some degree of crystallinity in the region 2q = 5–60 degree.The UV– visible spectra of some selected polymers were measured in DMSO solution and showed absorption bands in the range 265-397 nm, due to n – π* and π – π* transition. The morphological properties of copolymer IV as selected examples were tested by SEM. The electrical conductivities of the synthesized polymers and copolymers enhanced to become in the range of 10-9-10-8 S cm-1 by doping with iodine

    Global behavior of the difference equation x n+1 =

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    abstract: The aim of this work is to investigate the global stability, periodic nature, oscillation and the boundedness of all admissible solutions of the difference equation where A, B, C are positive real numbers

    Fetal lung volume and pulmonary artery resistance index for prediction of neonatal respiratory distress syndrome

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    Background: As gestational age grows, the risk of newborn respiratory distress syndrome (RDS) diminishes because the lungs are the last foetal organs to properly mature. While neonatal RDS does not just occur following preterm births, it is often thought of as a disorder of premature babies. This study sought to determine how prenatal lung capacity and foetal Pulmonary artery resistance index (PARI) affected the probability that newborn RDS would occur. Methods: This prospective observational study was carried out on 200 pregnant women aged 20-35 years, with gestational age between 36-40 weeks and singleton pregnancy. According to neonatal outcome the patients were classified into two groups: group A: 26 cases with noenatal RDS and group B: 174 cases without neonatal RDS. All patients were subjected to 2D ultrasonography and 3D ultrasonography. Results: Fetal lung volume (FLV) is a significant predictor of neonatal RDS (AUC: 0.820, p <0.001), at a cut off value of ≀35, with 88.5% sensitivity and 68.4% specificity. PARI is not a significant predictor of neonatal RDS. 1 and 5 min Apgar score were significantly lower in neonates who developed RDS and those who didn’t (p<0.001). Conclusions: 3D FLV and estimated fetal weight measurement using ultrasonography may be a reliable non-invasive indicator of the incidence of newborn RDS in preterm pregnancies when the risk of RDS progression is present. FLV is a significant predictor for neonatal RDS at a cutoff for ≀35 cm3 with sensitivity 88.5% and specificity 68.4%
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