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Now showing items 145 - 160 of 1618

  • Association between polymorphism of TGFA Taq I and cleft Lip and/or palate: a meta-analysis

    Cuijuan Feng   Enjiao Zhang   Weiyi Duan   Zhongfei Xu   Yang Zhang   Li Lu  

    Background: Cleft lip and palate (CL/P) is one of the most common malformations in humans. Transforming growth factor alpha (TGFA) is a well characterized mammalian growth factor which might contribute to the development of CL/P. This meta-analysis aimed to summarize the association between the TGFA Taq I polymorphisms and CL/P. Methods: We retrieved the relevant articles from PubMed, EMBASE, ISI Web of Science and SCOPUS databases. Studies were selected using specific inclusion and exclusion criteria. The odds ratios (ORs) and their 95% confidence intervals (95% CIs) were calculated to assess the association between TGFA Taq I polymorphism and CL/P risk. Meta-analyses were performed on the total data set and separately for the major ethnic groups, disease type and source of control. All analyses were performed using the Stata software. Results: Twenty articles were included in the present analysis. There is a significant association between the TGFA Taq I polymorphism and CL/P (C1C2 vs C1C1: OR = 1.67, 95% CI = 1.23-2.25, C2C2 + C1C2 vs C1C1C1: OR = 1.52, 95% CI = 1.15-2.01; C2 vs C1: OR = 1.41, 95% CI = 1.12-1.78). Stratified analyses suggested that the TGFA Taq I polymorphism was significantly associated with CL/P in Caucasians (C1C2 vs C1C1: OR = 1.95, 95% CI = 1.34-2.86; C2C2 + C1C2 vs C1C1: OR = 1.68, 95% CI = 1.18-2.38; C2 vs V1: OR = 1.52, 95% CI = 1.14 -2.02). Conclusion: TGFA Taq I polymorphism may be associated with the risk of CL/P.
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  • Online calibration of MOSFET on-state resistance for precise current sensing

    Yang Zhang   Zane, R.   Prodic, A.   Erickson, R.   Maksimovic, D.  

    An approach for online current sensing calibration is presented where an auxiliary switch and a precision sense resistor are connected in parallel with a main power switch to achieve accuracy comparable to the sense resistor method, together with the advantage of essentially no additional power loss. The proposed current-sensing circuit and the calibration methods are particularly well suited for digital controller implementations where the required control and calibration functions can be easily accomplished. Experimental results with a digitally controlled 1.5-V 15-A synchronous buck converter demonstrate functionality of the online calibration approach, showing a significant improvement in accuracy over voltage sensing across the power MOSFET on-resistance
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  • Ceramide-enriched membrane domains—Structure and function

    Yang Zhang   Xiang Li   Katrin Anne Becker   Erich Gulbins  

    Membrane lipids seem to be organized and not randomly distributed in the cell membrane. In particular, sphingolipids seem to interact with cholesterol in the outer leaflet of the cell membrane resulting in the formation of distinct membrane domains, i.e. rafts. The generation of ceramide within rafts alters their biophysical properties and results in the formation of large ceramide-enriched membrane platforms. These platforms serve to cluster receptor molecules and to organize intracellular signalling molecules to facilitate signal transduction via a receptor upon stimulation. Thus, ceramide-enriched membrane domains amplify not only receptor-, but also stress-mediated signalling events. Although many receptors cluster, the molecular mechanisms mediating this important and general event in signal transduction need to be identified.
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  • Edge city formation and the resulting vacated business district

    Yang Zhang   Komei Sasaki  

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  • Monitoring and troubleshooting a module associated with a portable communication device

    Methods, apparatuses, and software to monitor, troubleshoot, or diagnose one or more specialty modules associated with a portable communication device are provided. The methods, apparatuses, and software identify the specialty module, obtain and execute procedures to monitor, test, or diagnose the specialty module. If unsatisfactory, error, defective or the like performance is identified, a solution is applied to correct the performance.
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  • Personal health modules supported by portable communication devices

    A wireless device having a remote station portion, such as a cellular telephone, PDA, laptop computer, handheld computer, or the like and a removably connectable medical device portion, such as a blood glucose monitor or the like, is provided. The medical device portion is separated from the remote station portion by an isolation circuit and electromagnetic shielding to inhibit the electronics and radio frequency transmission of the remote station portion interfering with the medical device. Moreover, a control processor in the remote station portion has a battery management module to disable functions as the charge in the power source falls to provide sufficient power for operation of the medical device.
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  • Method for use in a digital frequency synthesizer

    A method for use in a digital frequency synthesizer, the method comprising phase to amplitude conversion of an output value of a phase accumulator in said synthesizer, said conversion being carried out as an approximation (y) of a phase value (x) which corresponds to said output amplitude value, the method being characterized in that the approximation comprises a combination of a linear interpolation value and a second order sinusoidal value, the second order sinusoidal value being used as an error term to correct for errors in the linear interpolation value.
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  • Migration of task to different pool of resources based on task retry count during task lease

    Systems and methods are presented for providing resources by way of a platform as a service in a distributed computing environment to perform a job. Resources of the system, job performing on the system, and schedulers of the jobs performing on the system are decoupled in a manner that allows a job to easily migrate among resources. It is contemplated that the migration of jobs from a first pool of resource to a second pool of resource is performed by the system without human intervention. The migration of a job may utilize different schedulers for the different resources. Further, it is contemplated that a pool of resources may automatically allocate additional or fewer resources in response to a migration of a job.
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  • Metallic lustre and the optical mechanism generated from the leaf surface of Begonia rex

    Yang Zhang   Takahiro Hayashi   Munetaka Hosokawa   Susumu Yazawa   Yuhua Li  

    The mechanism of sparkling metallic lustre formation in leaves of Begonia rex Putz. was investigated. On the metallic lustre and normal green areas of one leaf, we observed two light reflection patterns, one a spotted pattern (SP) composed of white spots formed on the centre of epidermal cells and the other a polygonal pattern (PP) composed of white polygons formed around the epidermal cell edges. The SP was observed both in metallic lustre and normal green areas, and the intensity did not differ significantly, but the PP was much stronger in the metallic lustre area. Different reflection of the PP in metallic lustre and normal green areas indicated that metallic lustre formation was attributable to the PP. Light reflection of the PP was mainly derived from interior light reflection because the PP became very weak after air removal from leaf. The formation of the PP is associated with the interior structure of the leaf, such as chlorophyll density, cell arrangement and air space. The experimental results indicated that interior air space is an important factor in forming the polygonal pattern.
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  • Letter: A Model of Dark Energy for the Accelerating Universe

    Yang Zhang  

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  • Stability of commercial metal oxide nanoparticles in water

    Yang Zhang   Yongsheng Chen   Paul Westerhoff   Kiril Hristovski   John C Crittenden  

    The fate of commercial nanoparticles in water is of significant interest to health and regulatory authorities. This research investigated the dispersion and stability of metal oxide nanoparticles in water as well as their removal by potable water treatment processes. Commercial nanoparticles were received as powder aggregates, and in water neither ultrasound nor chemical dispersants could break them up into primary nanoparticles. Lab-synthesized hematite was prepared as a primary nanoparticle (85nm) suspension; upon drying and 1-month storage, however, hematite formed aggregates that could not be dispersed completely as primary nanoparticles in water. This observation may explain why it is difficult to disperse dry commercial nanoparticles. Except for silica, other nanoparticles rapidly aggregated in tap water due to electric double layer (EDL) compression. The stability of silica in tap water is related to its low Hamaker constant. For all these nanoparticles, at an alum dosage of 60 mg/L, coagulation followed by sedimentation could remove 20-60% of the total nanoparticle mass. Filtration using a 0.45 mu m filter was required to remove more than 90% of the nanoparticle mass. (C) 2007 Elsevier Ltd. All rights reserved.
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  • Stability of commercial metal oxide nanoparticles in water

    Yang Zhang   Yongsheng Chen   Paul Westerhoff   Kiril Hristovski   John C Crittenden  

    The fate of commercial nanoparticles in water is of significant interest to health and regulatory authorities. This research investigated the dispersion and stability of metal oxide nanoparticles in water as well as their removal by potable water treatment processes. Commercial nanoparticles were received as powder aggregates, and in water neither ultrasound nor chemical dispersants could break them up into primary nanoparticles. Lab-synthesized hematite was prepared as a primary nanoparticle (85 nm) suspension; upon drying and 1-month storage, however, hematite formed aggregates that could not be dispersed completely as primary nanoparticles in water. This observation may explain why it is difficult to disperse dry commercial nanoparticles. Except for silica, other nanoparticles rapidly aggregated in tap water due to electric double layer (EDL) compression. The stability of silica in tap water is related to its low Hamaker constant. For all these nanoparticles, at an alum dosage of 60 mg/L, coagulation followed by sedimentation could remove 20–60%of the total nanoparticle mass. Filtration using a 0.45 μm filter was required to remove more than 90%of the nanoparticle mass.
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  • SPICKER: A clustering approach to identify near-native protein folds

    Yang Zhang   Jeffrey Skolnick  

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  • Combined p53-related genetic variants together with HPV infection increase oral cancer risk

    Zhongqiu Wang   Erich M. Sturgis   Yang Zhang   Zhigang Huang   Qi Zhou   Qingyi Wei and Guojun Li  

    To explore the role of polymorphisms of p53-related genes in etiology of oral cancer, we investigated joint effects of seven putatively functional polymorphisms of p53 (codon 72 Arg/Pro), p73 (4/14 GC/AT), murine double minute 2 gene (MDM2; A2164G and T2580G) and MDM4 (rs11801299 G > A, rs10900598 G > T and rs1380576 C > G) on risk of human papillomavirus (HPV)16-associated oral cancer in a case–control study with 325 cases and 335 cancer-free controls. We found that HPV16 seropositivity alone was associated with an increased risk of oral cancer [adjusted odds ratio (OR), 3.1; 95% confidence interval (CI), 2.1–4.6]. After combining genotypes of seven polymorphisms and using the low-risk group (0–3 combined risk genotypes) and HPV16 seronegativity as the reference group, the medium-risk (4 combined risk genotypes) and high-risk groups (5–7 combined risk genotypes) and HPV16 seronegativity were associated with only an OR of 1.6 (95% CI, 1.1–2.5) and 1.2 (95% CI, 0.7–1.9) for oral cancer risk, respectively, whereas the low-risk, medium-risk and high-risk groups and HPV16 seropositivity were significantly associated with a higher OR of 2.1 (95% CI, 1.2–3.6), 4.0 (95% CI, 1.8–9.1) and 19.1 (95% CI, 5.7–64.2), respectively. Notably, such effect modification by these combined risk genotypes was particularly pronounced in young subjects (aged < 50 years), never smokers and patients with oropharyngeal cancer. Taken together, these findings suggest that the combined risk genotypes of p53-related genes may modify risk of HPV16-associated oral cancer, especially in young patients, never-smokers and patients with oropharyngeal cancer. Larger studies are needed to validate our findings.
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  • Error estimates of CFVE method for fully nonlinear convection-dominated diffusion problems

    Yang Zhang  

    Abstract Finite volume method and characteristics finite element method are two important methods for solving the partial differential equations. These two methods are combined in this paper to establish a fully discrete characteristics finite volume method for fully nonlinear convection-dominated diffusion problems. Through detailed theoretical analysis, optimal order H1 norm error estimates are obtained for this fully discrete scheme. Copyright © 2010 John Wiley & Sons, Ltd.
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  • I-TASSER server for protein 3D structure prediction

    Yang Zhang  

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