5,651 research outputs found

    Study of the Top-quark Pair Production in Association with a Bottom-quark Pair from Fast Simulations at the LHC

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    A large number of top quarks will be produced at the Large Hadron Collider (LHC) for Run II period. This will allow us to measure the rare processes from the top sector in great details. We present the study of the top-quark pair production in association with a bottom-quark pair (ttbb) from fast simulations for the Compact Muon Solenoid (CMS) experiment. The differential distributions of ttbb are compared with the top-quark pair production with two additional jets (ttjj) and with the production in association with the Higgs (ttH), where the Higgs decays to a bottom-quark pair. The significances of ttbb process in the dileptonic and semileptonic decay mode are calculated with the data corresponding to an integrated luminosity of 10 fb-1, which is foreseen to be collected in the early Run II period. This study will be an important input in searching for new physics beyond the standard model as well as in searching for ttH process where the Yukawa coupling with the top quark can be directly measured.Comment: 12 pages, 12 figure

    Biological and Biochemical Characterization of a Tick Feeding Stimuli Responsive Amblyomma americanum Acidic Chitinase in Tick Feeding Physiology

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    Without successful feeding, ticks can neither cause damage to their host nor transmit disease agents. Thus, a deeper understanding of tick physiology as a means to discover weaknesses that can be targeted for tick control is needed. In a previous study, 40 genes were discovered that are differentially up regulated in Amblyomma americanum (Aam) (Linnaeus) females when exposed to feeding stimuli. The purpose of this study was to biologically and biochemically characterize one of the 40 candidate genes, a putative acidic chitinase (Ach), to understand its role(s) and significance in regulating tick feeding physiology. This research has shown that A. americanum expresses two putative AamAch isoforms [long (L) and short (S)], both of which are classified into the glycosyl hydrolase 18 (GH-18) family. Members of the GH-18 are involved in regulating multiple functions including nutrition processes in bacteria, morphogenesis in yeast and fungi, pathogen attack in plants, molting in insects, and inflammation and tissue remodeling in mammals. Spatial and temporal mRNA transcript analyses show that putative AamAch-L and AamAch-S are ubiquitously expressed, with highest transcript abundance post-attachment observed at 72h in all tissues, and at 96h in the salivary gland. Pichia pastoris-expressed recombinant AamAch-L was glycosylated, consistent with molecular analysis that predicted N- and O-linked glycosylation sites. Substrate hydrolysis analysis indicated that rAamAch-L does not apparently have chitinase activity. RNAi mediated silencing of AamAch mRNA apparently caused loosening or weakening of the tick cement plug at the feeding site. Animals injected with AamAch-dsRNA bled around mouthparts, and were loosely attached on its rabbit host in that they easily detached with a light touch. The putative AamAch is therefore potentially involved in mediating tick attachment onto host skin. This thesis research advances our knowledge on the understanding of the molecular basis of tick feeding physiology and provides new information on the diverse physiological role of acidic chitinase-like proteins

    Wetting Behavior of Dental Implants

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    Titanium (Ti) and titanium alloys are widely used in biomedical devices and components, because of their desirable properties, such as relatively low modulus, good fatigue strength, formability, machinability, corrosion resistance, and biocompatibility. However, Ti and its alloys cannot meet all of the clinical requirements. Therefore, surface modification of Ti has been often performed to improve the biological, chemical, and mechanical properties. Various modifications of surface properties have been investigated to predictably improve the osseointegration of Ti implants. The rate and quality of osseointegration in Ti implants are related to their surface properties. A multiplicity of implant surface forms exist engineered with mechanical features that physically interlock the implant with bone. Various strategies have been utilized to improve bone integration of Ti-based implants. For example, surface grit blasting, acid-etching and anodization methods enhance cell growth, improving implant fixation through increases in interlocking surface area and alterations of oxide thickness. On the other hand, surface composition and hydrophilicity are parameters that may play a role in implant-tissue interaction and osseointegration. Highly hydrophilic surfaces seem more desirable than hydrophobic ones in view of their interactions with biological fluids, cells and tissues. Several recent studies have shown that the surface energy of biomaterials strongly has influence the initial cell attachment and spreading of osteoblastic cells on the biomaterial surfaces. Hallab et al. said that surface energy might be a more important determinant of cell adhesion and proliferation, and might be more useful than surface roughness for generating cell adhesion and cell. It may have the influence on protein adsorption and the structural rearrangement of the proteins on the material. Therefore, understanding the relationship between surface energy and cell adhesion on different biomaterials will facilitate the design of optimized implant material surfaces and subsequently the cell attachment. Surface energy is an important parameter of the material surface. It is affected by several surface characteristics, such as chemical composition, surface charge, and microstructural topography. Many papers reported that surface energy is one of important surface characteristics parameter of modified titanium surfaces. Given the importance of surface wettability of dental implants surfaces in the achievement of osseointegration, the surface free energy values for a given material, obtained by various methods and with use of different measuring liquids, are not consistent. Thus, we provided a review article of the surface modification on titanium surface and the surface wettability. The relationship between CAs and surface preparations was determined in this review

    One-Sided Competition in Two-Sided Social Platform Markets? An Organizational Ecology Perspective

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    Similar to love, competition can often be unrequited. This study explores the asymmetric pattern of competition driven by membership overlap in two-sided mobile social apps (MSAs) markets. Building on the niche-width dynamics framework, we theorize and validate the relative prevalence and survival capabilities of messaging apps and SNS apps, especially when membership overlap fosters current or potential competition between the two app categories. The analyses—based on panel dataset consisting of information on 8,483 panel members’ exact amount of time used for 21 mobile social apps—show that competition between SNS and messaging apps can be asymmetric in favor of messaging apps. This asymmetric pattern is more pronounced for membership-based competition compared to usage-based competition. In addition, different MSAs developed by same platform providers exhibit synergistic effects, rather than destructive consequences, on each other’s growth. The findings identify the complex nature of competition within-category and between-category competition in MSAs markets

    Identification of C16orf74 as a Marker of Progression in Primary Non-Muscle Invasive Bladder Cancer

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    PURPOSE: Methylation-induced silencing of PRSS3 has been shown to be significantly associated with invasive bladder cancer, and expression of the C16orf74 gene locus has been shown to correlate positively with PRSS3. The aim of the current study was to evaluate the relationship between C16orf74 expression level and progression in non-muscle invasive bladder cancer (NMIBC). MATERIALS AND METHODS: C16orf74 mRNA levels were examined by real-time reverse transcriptase polymerase chain reaction (RT-PCR) analysis of 193 tumor specimens from patients with primary NMIBC. Expression data were analyzed in terms of clinical and experimental parameters. Kaplan-Meier curves and multivariate Cox regression models, respectively, were used to determine progression-free survival and to identify independent predictive parameters of progression. RESULTS: Analysis using Kaplan-Meier curves revealed prolonged progression-free survival of high-C16orf74-expressors as compared to low-expressors (p<0.001). Multivariate Cox regression analysis revealed that low C16orf74 mRNA expression levels are a significant risk factor for disease progression in patients with primary NMIBC (HR: 10.042, CI:2.699-37.360, p = 0.001). CONCLUSIONS: Decreased expression of C16orf74 correlates significantly with progression in primary NMIBC. C16orf74 expression level represents a potentially useful marker for predicting progression in primary NMIBC patients

    Application of Copula-Based Markov Model to Generate Monthly Precipitation

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    Source: ICHE Conference Archive - https://mdi-de.baw.de/icheArchiv

    Alpha-tocopherol exerts protective function against the mucotoxicity of particulate matter in amphibian and human goblet cells

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    Exposure to particulate matter (PM) in ambient air is known to increase the risk of cardiovascular disorders and mortality. The cytotoxicity of PM is mainly due to the abnormal increase of reactive oxygen species (ROS), which damage cellular components such as DNA, RNA, and proteins. The correlation between PM exposure and human disorders, including mortality, is based on long-term exposure. In this study we have investigated acute responses of mucus-secreting goblet cells upon exposure to PM derived from a heavy diesel engine. To this end, we employed the mucociliary epithelium of amphibian embryos and human Calu-3 cells to examine PM mucotoxicity. Our data suggest that acute exposure to PM significantly impairs mucus secretion and results in the accumulation of mucus vesicles in the cytoplasm of goblet cells. RNA-seq analysis revealed that acute responses to PM exposure significantly altered gene expression patterns; however, known regulators of mucus production and the secretory pathway were not significantly altered. Interestingly, pretreatment with alpha-tocopherol nearly recovered the hyposecretion of mucus from both amphibian and human goblet cells. We believe this study demonstrates the mucotoxicity of PM and the protective function of alpha-tocopherol on mucotoxicity caused by acute PM exposure from heavy diesel engines

    Vegetation change in the regional surface climate over East Asia due to global warming using BIOME4

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    This study investigates the possible changes in the regional surface climate due to global warming from a MM5 downscaling simulation for the period of 1971-2100. The main focus of this study is to observe the changes in vegetation types over East Asia. BIOME4, an equilibrium terrestrial biosphere model, is utilized to simulate vegetation patterns. Regional projections of this study show the increase of surface air temperature by 5◦C and precipitation by 6% over East Asia in the end of the 21st century. The present study also noticed that the increasing trend of temperature is associated with the increasing trends of the minimum temperature of the coldest month. Therefore, the region of favorable temperature conditions for vegetation growth in lower latitudes seems to extend toward the higher latitude. It leads to a northward shift of vegetation distribution in the lower latitudes besides the area extension. For instance, the trend in which the warm mixed forest and temperate deciduous forest shift northward may be distinguished. At the same time, the area of temperate deciduous forest pervades the area and replaces temperate grassland regions. Of interest, the tropical evergreen forest is expected to appear over southern China in the end of the 21st century. The possible vegetation changes are mainly affected by a temperature increase rather than a precipitation increase

    The Devil in the Details: Simple and Effective Optical Flow Synthetic Data Generation

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    Recent work on dense optical flow has shown significant progress, primarily in a supervised learning manner requiring a large amount of labeled data. Due to the expensiveness of obtaining large scale real-world data, computer graphics are typically leveraged for constructing datasets. However, there is a common belief that synthetic-to-real domain gaps limit generalization to real scenes. In this paper, we show that the required characteristics in an optical flow dataset are rather simple and present a simpler synthetic data generation method that achieves a certain level of realism with compositions of elementary operations. With 2D motion-based datasets, we systematically analyze the simplest yet critical factors for generating synthetic datasets. Furthermore, we propose a novel method of utilizing occlusion masks in a supervised method and observe that suppressing gradients on occluded regions serves as a powerful initial state in the curriculum learning sense. The RAFT network initially trained on our dataset outperforms the original RAFT on the two most challenging online benchmarks, MPI Sintel and KITTI 2015
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