683 research outputs found

    Approximation of conformal mappings using conformally equivalent triangular lattices

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    Consider discrete conformal maps defined on the basis of two conformally equivalent triangle meshes, that is edge lengths are related by scale factors associated to the vertices. Given a smooth conformal map ff, we show that it can be approximated by such discrete conformal maps fϵf^\epsilon. In particular, let TT be an infinite regular triangulation of the plane with congruent triangles and only acute angles (i.e.\ <π/2<\pi/2). We scale this tiling by ϵ>0\epsilon>0 and approximate a compact subset of the domain of ff with a portion of it. For ϵ\epsilon small enough we prove that there exists a conformally equivalent triangle mesh whose scale factors are given by logf\log|f'| on the boundary. Furthermore we show that the corresponding discrete conformal maps fϵf^\epsilon converge to ff uniformly in C1C^1 with error of order ϵ\epsilon.Comment: 14 pages, 3 figures; v2 typos corrected, revised introduction, some proofs extende

    Helicobacter pylori infection is associated with increased expression of macrophage migratory inhibitory factor - by epithelial cells, T cells, and macrophages - in gastric mucosa

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    The macrophage migratory inhibitory factor (MIF) plays a pivotal role in inflammatory and immune diseases; however, its role in gastrointestinal diseases has not been clarified. This study intended to determine the expression of MIF, by gastric epithelial cells, T cells, and macrophages, in Helicobacter pylori-induced gastritis. Sixty-four patients (30 males, 34 females; mean age, 47 years) referred for upper endoscopy were recruited. Biopsy specimens from the gastric antrum and corpus were obtained for (1) detection of H. pylori and histological examination, (2) single and double immunostaining to test for expression of MIF protein in epithelial cells, T cells, and macrophages, and (2) in situ hybridization for expression of MIF mRNA within the lamina propria. In mucosal specimens from each of the 2 sites, both the percentage of MIF + epithelial cells and the numbers of MIF mRNA+ inflammatory cells, MIF+ T cells, and MIF+ macrophages were significantly higher in H. pylori-positive patients than in H. pylori-negative patients. Overall, the percentage of MIF+ epithelial cells and the numbers of MIF mRNA+ cells, MIF+ T cells, and MIF+ macrophages were higher in the antrum than in the corpus. The percentage of MIF+ epithelial cells and the numbers of MIF mRNA+ cells, MIF+ T cells, and MIF+ macrophages increased in chronic gastritis, but, in the absence of H. pylori infection, this increase disappeared for all except MIF+ T cells. Therefore, H. pylori infection is associated with increased expression of the MIF protein and MIF mRNA in gastric epithelial and inflammatory cells; along with other cytokines, MIF may play a significant role in gastric inflammation related to H. pylori infection.published_or_final_versio

    Expression of macrophage migration inhibitory factor in Helicobacter pylori-induced gastritis and peptic ulcer disease

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    P2P Lending platforms in Malaysia: the awareness among Malaysian adults [version 3; peer review: 2 approved]

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    Background: Since 2016, the Securities Commission (SC) in Malaysia has given licenses to only eleven P2P lending platforms. Such lending platforms are expected to disrupt the lending services of traditional lenders in the coming years. However, being still in their infant stages, it is essential to know the extent to which such platforms are made known to potential investors out there. This study aims to examine the awareness level of the eleven P2P lending platforms among Malaysian adults. The study also explores if past investment experience and financial knowledge would influence such awareness from Malaysian adults. Methods: A sample of 335 Malaysian individuals was used for this study. An online questionnaire was designed with three main parts: demographic, financial literacy, and P2P lending awareness. Using IBM SPSS Statistics 26, frequency, descriptive, normality, Pearson coefficients and multiple regression analyses were carried out.  Results: Although seven out of ten respondents have good knowledge in three areas of finance: compounding rate, inflation and diversification, only 14.33% had a good and excellent awareness level of P2P lending. Thus, one would expect lesser awareness about P2P lending among Malaysian adults whose financial literacy is poor or zero. Test results from multiple regression analysis suggest that past lending experiences positively affect the awareness of P2P lending in Malaysia, but not the financial literacy. Conclusions: The awareness about P2P lending among Malaysian adults is too low, despite their high level of education and financial literacy. No investing experience and not knowing any existing P2P lending in the country may be the reason for this low awareness. Therefore, for P2P lending to thrive in Malaysia, the eleven P2P lending platforms need to be promoted aggressively in various social media outlets

    5-Hy­droxy-3,4′,6,7-tetra­meth­oxy­flavone

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    The title compound, C19H18O7 [systematic name 5-hy­droxy-3,6,7-tri­meth­­oxy-2-(4-meth­oxy­phen­yl)-4H-1-benzopyran-4-one], is a flavonoid which was isolated from the traditional Chinese medicine Laggera alata. The benzene ring of the benzopyran­one unit forms dihedral angles of 1.72 (3) and 37.39 (5)° with the pyran ring and the substituent benzene ring, respectively. The mol­ecular conformation is stabilized by an intra­molecular phenol O—H⋯Oketone hydrogen bond

    Overexpression of eIF-5A2 in mice causes accelerated organismal aging by increasing chromosome instability

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    <p>Abstract</p> <p>Background</p> <p>Amplification of 3q26 is one of the most frequent genetic alterations in many human malignancies. Recently, we isolated a novel oncogene <it>eIF-5A2 </it>within the 3q26 region. Functional study has demonstrated the oncogenic role of <it>eIF-5A2 </it>in the initiation and progression of human cancers. In the present study, we aim to investigate the physiological and pathological effect of <it>eIF-5A2 </it>in an <it>eIF-5A2 </it>transgenic mouse model.</p> <p>Methods</p> <p>An <it>eIF-5A2 </it>transgenic mouse model was generated using human <it>eIF-5A2 </it>cDNA. The <it>eIF-5A2 </it>transgenic mice were characterized by histological and immunohistochemistry analyses. The aging phenotypes were further characterized by wound healing, bone X-ray imaging and calcification analysis. Mouse embryo fibroblasts (MEF) were isolated to further investigate molecular mechanism of <it>eIF-5A2 </it>in aging.</p> <p>Results</p> <p>Instead of resulting in spontaneous tumor formation, overexpression of eIF-5A2 accelerated the aging process in adult transgenic mice. This included decreased growth rate and body weight, shortened life span, kyphosis, osteoporosis, delay of wound healing and ossification. Investigation of the correlation between cellular senescence and aging showed that cellular senescence is not required for the aging phenotypes in <it>eIF-5A2 </it>mice. Interestingly, we found that activation of <it>eIF-5A2 </it>repressed p19 level and therefore destabilized p53 in transgenic mouse embryo fibroblast (MEF) cells. This subsequently allowed for the accumulation of chromosomal instability, such as errors in cell dividing during metaphase and anaphase. Additionally, a significantly increase in number of aneuploidy cells (<it>p </it>< 0.05) resulted from an increase in the incidences of misaligned and lagging chromosomal materials, anaphase bridges, and micronuclei in the transgenic mice.</p> <p>Conclusion</p> <p>These observations suggest that <it>eIF-5A2 </it>mouse models could accelerate organismal aging by increasing chromosome instability.</p
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