941 research outputs found

    Repair of corroded steel beam using CFRP

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    Many steel structures were built during World War I and II. More than twenty percent of steel bridges in the USA are structurally deficient. The cost for rehabilitation in most cases is far less than the cost of replacement. Moreover, the rehabilitation generally takes less time than replacement. Due to the limited methods available to mitigate this problem, new materials were explored in recent years to adopt cost-effective technique to address this issue. This thesis focuses on the use of Carbon Fiber Reinforced Polymer (CFRP) sheets as a competitive technique to restore the capacity of surface corroded steel beam. Rehabilitation was achieved by bonding the CFRP fabrics on to the corroded area of the bottom flange of steel beams. A series of tests and finite element analyses were also conducted. Results showed that the ultimate load capacity of the rehabilitated structures can be restored using this method; however, ductility reduces

    FACEBOOK EWOM MARKETING STRATEGY: A SOCIAL SUPPORT THEORY PERSPECTIVE

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    Today, social media is a major communication medium for online users. Along the use of social media, electronic word-of-mouth (EWOM) is a common user behavior. To understating the Facebook marketing and form marketing strategy has become an increasingly important issue. Facebook ranks at top one social medium where the posts on food and dining ranks at top 5 topics. To understand the EWOM behavior, this study investigates that positive and negative EWOM over Facebook. Both social exchange theory and social support theory are applied in our study. The results suggest that trust and social support are the major reason that influence customer satisfaction and dissatisfaction of Facebook, which in turn influence the positive and negative EWOM intention respectively. The theoretical contribution of our study lies in the application of two social theories in online context. The empirical contribution is to provide our findings to e-retailers to create positive EWOM meanwhile to avoid negative EWOM. The results of our study benefits e-retailers to build up positive reputations and form marketing strategy for business growth

    The Nonsubsampled Contourlet Transform Based Statistical Medical Image Fusion Using Generalized Gaussian Density

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    We propose a novel medical image fusion scheme based on the statistical dependencies between coefficients in the nonsubsampled contourlet transform (NSCT) domain, in which the probability density function of the NSCT coefficients is concisely fitted using generalized Gaussian density (GGD), as well as the similarity measurement of two subbands is accurately computed by Jensen-Shannon divergence of two GGDs. To preserve more useful information from source images, the new fusion rules are developed to combine the subbands with the varied frequencies. That is, the low frequency subbands are fused by utilizing two activity measures based on the regional standard deviation and Shannon entropy and the high frequency subbands are merged together via weight maps which are determined by the saliency values of pixels. The experimental results demonstrate that the proposed method significantly outperforms the conventional NSCT based medical image fusion approaches in both visual perception and evaluation indices

    PointGPT: Auto-regressively Generative Pre-training from Point Clouds

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    Large language models (LLMs) based on the generative pre-training transformer (GPT) have demonstrated remarkable effectiveness across a diverse range of downstream tasks. Inspired by the advancements of the GPT, we present PointGPT, a novel approach that extends the concept of GPT to point clouds, addressing the challenges associated with disorder properties, low information density, and task gaps. Specifically, a point cloud auto-regressive generation task is proposed to pre-train transformer models. Our method partitions the input point cloud into multiple point patches and arranges them in an ordered sequence based on their spatial proximity. Then, an extractor-generator based transformer decoder, with a dual masking strategy, learns latent representations conditioned on the preceding point patches, aiming to predict the next one in an auto-regressive manner. Our scalable approach allows for learning high-capacity models that generalize well, achieving state-of-the-art performance on various downstream tasks. In particular, our approach achieves classification accuracies of 94.9% on the ModelNet40 dataset and 93.4% on the ScanObjectNN dataset, outperforming all other transformer models. Furthermore, our method also attains new state-of-the-art accuracies on all four few-shot learning benchmarks.Comment: 9 pages, 2 figure

    Organic cation transporter 1 (OCT1) modulates multiple cardiometabolic traits through effects on hepatic thiamine content.

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    A constellation of metabolic disorders, including obesity, dysregulated lipids, and elevations in blood glucose levels, has been associated with cardiovascular disease and diabetes. Analysis of data from recently published genome-wide association studies (GWAS) demonstrated that reduced-function polymorphisms in the organic cation transporter, OCT1 (SLC22A1), are significantly associated with higher total cholesterol, low-density lipoprotein (LDL) cholesterol, and triglyceride (TG) levels and an increased risk for type 2 diabetes mellitus, yet the mechanism linking OCT1 to these metabolic traits remains puzzling. Here, we show that OCT1, widely characterized as a drug transporter, plays a key role in modulating hepatic glucose and lipid metabolism, potentially by mediating thiamine (vitamin B1) uptake and hence its levels in the liver. Deletion of Oct1 in mice resulted in reduced activity of thiamine-dependent enzymes, including pyruvate dehydrogenase (PDH), which disrupted the hepatic glucose-fatty acid cycle and shifted the source of energy production from glucose to fatty acids, leading to a reduction in glucose utilization, increased gluconeogenesis, and altered lipid metabolism. In turn, these effects resulted in increased total body adiposity and systemic levels of glucose and lipids. Importantly, wild-type mice on thiamine deficient diets (TDs) exhibited impaired glucose metabolism that phenocopied Oct1 deficient mice. Collectively, our study reveals a critical role of hepatic thiamine deficiency through OCT1 deficiency in promoting the metabolic inflexibility that leads to the pathogenesis of cardiometabolic disease

    SYK-targeted dendritic cell-mediated cytotoxic T lymphocytes enhance the effect of immunotherapy on retinoblastoma

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    Purpose: Retinoblastoma (RB) is the most common primary intraocular tumor in children. Chemotherapy is currently the main method of RB treatment. Unfortunately, RB often becomes chemoresistant and turns lethal. Here, we used in vitro cell immunotherapy to explore whether adoptive immunotherapy could be used as a potential treatment for RB. We focused on spleen tyrosine kinase (SYK), which is significantly upregulated in RB cells and serves as a marker for RB cells. Methods: Using lentiviruses, we genetically modified dendritic cells (DCs) to express and present the SYK peptide antigen to cytotoxic T lymphocytes (CTLs) in vitro. We used SYK-negative cell lines (MDA-MB-231, MCF-10A, and hTERT-RPE1) and SYK-positive cell lines (MCF-7 and RB-Y79) to evaluate the specificity and cytotoxicity of DC presented CTLs using FACS, live-cell imaging, and RNA interference. Results: The cytotoxicity of CTLs induced by SYK-overexpressing DCs (SYK-DC–CTLs) was enhanced more than three times in SYK-positive cell lines compared with SYK-negative cell lines. DCs primed with SYK could drive CTL cytotoxicity against SYK-positive cell lines but not against SYK-negative cell lines. Moreover, SYK-silenced RB-Y79 cells successfully evaded the cytotoxic attack from SYK-DC–CTLs. However, SYK-DC–CTLs could target SYK overexpressed hTERT-RPE1 cells, suggesting that SYK is a specific antigen for RB. Furthermore, SYK-DC–CTL exhibited specific cytotoxicity against carboplatin-resistant RB-Y79 cells in vitro. Conclusions: Our data showed that SYK could be a potential immunotherapy target mediated by DCs. We propose SYK as a candidate target for treatment of chemoresistant RB.Fil: Chen, Xuemei. Xi'an Jiaotong University; ChinaFil: Kunda, Patricia Elena. Instituto Universitario de Ciencias Biomédicas de Córdoba; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; ArgentinaFil: Lin, Jianwei. Shenzhen University; ChinaFil: Zhou, Meiling. Shenzhen Luohu Peoples Hospital; China. Shenzhen University; ChinaFil: Huang, Jinghan. Shenzhen Luohu Peoples Hospital; ChinaFil: Zhang, Huqin. Xi'an Jiaotong University; ChinaFil: Liu, Tao. Shenzhen University; China. Shenzhen Luohu Peoples Hospital; Chin

    Co-existence of multiple distinct lineages in Vibrio parahaemolyticus serotype O4:K12

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    Vibrio parahaemolyticus is an important cause of foodborne gastroenteritis globally. Thermostable direct haemolysin (TDH) and the TDH-related haemolysin are the two key virulence factors in V. parahaemolyticus. Vibrio pathogenicity islands harbour the genes encoding these two haemolysins. The serotyping of V. parahaemolyticus is based on the combination of O and K antigens. Frequent recombination has been observed in V. parahaemolyticus , including in the genomic regions encoding the O and K antigens. V. parahaemolyticus serotype O4:K12 has caused gastroenteritis outbreaks in the USA and Spain. Recently, outbreaks caused by this serotype of V. parahaemolyticus have been reported in China. However, the relationships among this serotype of V. parahaemolyticus strains isolated in different regions have not been addressed. Here, we investigated the genome variation of the V. parahaemolyticus serotype O4:K12 using the whole-genome sequences of 29 isolates. We determined five distinct lineages in this strain collection. We observed frequent recombination among different lineages. In contrast, little recombination was observed within each individual lineage. We showed that the lineage of this serotype of V. parahaemolyticus isolated in America was different from those isolated in Asia and identified genes that exclusively existed in the strains isolated in America. Pan-genome analysis showed that strain-specific and cluster-specific genes were mostly located in the genomic islands. Pan-genome analysis also showed that the vast majority of the accessory genes in the O4:K12 serotype of V. parahaemolyticus were acquired from within the genus Vibrio . Hence, we have shown that multiple distinct lineages exist in V. parahaemolyticus serotype O4:K12 and have provided more evidence about the gene segregation found in V. parahaemolyticus isolated in different continents
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