244 research outputs found

    First-principles method of propagation of tightly bound excitons: exciton band structure of LiF and verification with inelastic x-ray scattering

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    We propose a simple first-principles method to describe propagation of tightly bound excitons. By viewing the exciton as a composite object (an effective Frenkel exciton in Wannier orbitals), we define an exciton kinetic kernel to encapsulate the exciton propagation and decay for all binding energy. Applied to prototypical LiF, our approach produces three exciton bands, which we verified quantitatively via inelastic x-ray scattering. The proposed real-space picture is computationally inexpensive and thus enables study of the full exciton dynamics, even in the presence of surfaces and impurity scattering. It also provides intuitive understanding to facilitate practical exciton engineering in semiconductors, strongly correlated oxides, and their nanostructures.Comment: 5 pages, 4 figures. Accepted by PR

    Association of DRD4 uVNTR and TP53 codon 72 polymorphisms with schizophrenia: a case-control study

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    <p>Abstract</p> <p>Background</p> <p>The tumour supressor gene TP53 is thought to be involved in neural apoptosis. The polymorphism at codon 72 in TP53 and the long form variants of the upstream variable number of tandem repeats (uVNTR) polymorphism in the dopamine D4 receptor (DRD4) gene are reported to confer susceptibility to schizophrenia.</p> <p>Methods</p> <p>We recruited 934 patients with schizophrenia and 433 healthy individuals, and genotyped the locus of the TP53 codon 72 and DRD4 uVNTR polymorphisms by combining the polymerase chain reaction-restriction fragment length polymorphism method (PCR-RFLP) with direct sequencing.</p> <p>Results</p> <p>No significant differences were found in the frequency of the genotype of the TP53 codon72 polymorphism between patients with schizophrenia and their controls. However, the long form alleles (≄ 5 repeats) of the DRD4 uVNTR polymorphism were more frequent in patients with schizophrenia than in controls (p = 0.001). Hence, this class of alleles might be a risk factor for enhanced vulnerability to schizophrenia (odds ratio = 3.189, 95% confidence interval = 1.535-6.622). In the logistic regression analysis, the long form variants of the DRD4 polymorphism did predict schizophrenia after the contributions of the age and gender of the subjects were included (p = 0.036, OR = 2.319), but the CC and GG genotypes of the codon 72 polymorphism of TP53 did not.</p> <p>Conclusions</p> <p>The long form variants of the uVNTR polymorphism in DRD4 were associated with schizophrenia, in a manner that was independent of the TP53 codon 72 polymorphism. In addition, given that the genetic effect of the TP53 codon 72 polymorphism on the risk of developing schizophrenia was very small, this polymorphism is unlikely to be associated with schizophrenia. The roles that other single nucleotide polymorphisms (SNPs) in the TP53 gene or in other apoptosis-related genes play in the synaptic dysfunction involved in the pathogenesis of schizophrenia should be investigated.</p

    Enhancing National Chi Nan University Campus’s Ecological Friendliness by Creating a Butterfly Habitat Using Reclaimed Water

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    The campus of National Chi Nan University (NCNU), Taiwan is about 150 hectares, and surrounded by dense valleys and forests that provides a habitat for many wild animals. In order to further enhance the ecological friendliness of the campus, the school implemented courses to create habitats for butterflies around the Sun Pond in the campus. The reclaimed water, originated from Water Treatment Factory, in the Sun Pond is used to irrigate the vegetation in the habitat to enhance the ecological conservation value. From 2019 to 2020, a number of 17 species with 670 individuals and food plants for butterflies was planted, and special instruction signs focusing on butterfly ecology were set up, so that staff and students can better understand the actions and goals in ecological conservation of green university. From 2020 to mid-2021, a total of 6 courses with 750 students (13% of the total number of students) visited the wonderful habit. The number of 22 species of butterflies was recorded in the habitat and this number was an average of 132 per 30 minutes, which shows that the construction of the habitats is successful. The creation of the butterfly habitat is in line with United Nations Sustainable Development Goal (SDG) 6 and SDG 15. The habitat has become a distinguished place for environmental education in the university. In the future, more community residents and tourists can experience this fantastic place and realize the efforts and achievements in ecological conservation succeeded by NCNU.Keyword: Butterfly Habitat, Reclaimed Water, Green University, Environmental Education, Community Resident

    Numerical modeling of unsaturated layered soil for rainfall-induced shallow landslides

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    In this paper, a pioneer study on numerical modeling of rainfall-induced shallow landslides in unsaturated layered soil using the variably saturated flow equation is presented. To model the shallow landslides, the infinite slope stability analysis coupled with the hydrological model with the consideration of the fluctuation of time-dependent pore water pressure and Gardner equation for soil water characteristic curve was developed. A linearization process for the nonlinear Richards equation to deal with groundwater flow in unsaturated layered soil is derived using the Gardner model. To solve one-dimensional flow in the unsaturated zone of layered soil profiles, flux conservation and the continuity of pressure potential at the interface between two consecutive layers are considered in the numerical discretization of the finite difference method. The validity of the proposed model is established in three numerical problems by comparing the results with the analytical and other numerical solutions. Application examples have also been conducted. Obtained results demonstrate that the fluctuation of pore water pressure in unsaturated layered soil dominates slope stability of landslides and the lowest factor of safety may occur at the interface between two consecutive layers. The findings observed in this study are a fundamental contribution to environmental protection engineering for landslides in areas with higher occurrence and vulnerability to extreme precipitation

    The relationship between gallbladder status and recurrent biliary complications in patients with choledocholithiasis following endoscopic treatment

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    AbstractBackgroundEndoscopic methods are currently the treatment of choice for patients with common bile duct (CBD) stones, but subsequent management of the intact gallbladder for patients following endoscopic treatment is still controversial. The primary aim of this study was to discover the association between gallbladder status and recurrent biliary complications for patients with CBD stones after endoscopic treatment. Additionally, we also sought to determine risk factors for recurrent biliary complications in these patients.MethodsThe records of 1625 patients with CBD stones following endoscopic treatment were reviewed. A total of 681 patients were enrolled and subsequently categorized into four groups: Group 1 (n = 201), calculous gallbladder; Group 2 (n = 140), acalculous gallbladder; Group 3 (n = 175), elective cholecystectomy after endoscopic treatment; and Group 4 (n = 165), prior cholecystectomy. The basic demographics and recurrent biliary complications during follow-up among these four groups were analyzed by Chi-square test, ANOVA, Kaplan-Meier analysis, and log-rank test.ResultsDuring the median follow-up period of 34 months, 133 patients (20%) with recurrent biliary complications were identified. The recurrence rates of Groups 1, 2, 3, and 4 were 29%, 11%, 15%, and 19%, respectively. Kaplan-Meier analysis showed that patients with calculous gallbladder had a significantly higher rate of recurrent biliary complication. In multivariate analysis, patients with a history of cirrhosis, juxta-papillary diverticulum, calculous gallbladder, CBD size ≄1.5 cm, and endoscopic management with endoscopic sphincterotomy were at a higher risk for developing biliary complications (p = 0.029, p = 0.039, p < 0.001, p = 0.002, p = 0.021, respectively.)ConclusionPatients with cholecystolithiasis and CBD stones had a higher incidence of recurrent biliary complications. For some of these patients, elective cholecystectomy following endoscopic treatment may be considered. However, routine elective cholecystectomy in patients with normal gallbladder is not appropriate because of the low recurrence of biliary complications. Whether gallbladder function affects the biliary clearance and biliary complications requires further research
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