347 research outputs found

    Application of the transferrin receptor-mediated drug delivery systems in the treatment of acute cerebral infarction

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    2004-2005 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

    Ge/Si interdiffusion in the GeSi dots and wetting layers

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    The Ge/Si interdiffusion in GeSi dots grown on Si (001) substrate by gas-source molecular beam epitaxy is investigated. Transmission electron microscopy images show that, after annealing, the aspect ratio of the height to base diameter increases. Raman spectra show that the Si-Ge mode redshifts and the intensity of the local Si-Si mode increases with the increase of annealing temperature, which suggests the Ge/Si interdiffusion during annealing. The photoluminescence peaks from the dots and the wetting layers show blueshift due to the atomic intermixing during annealing. The interdiffusion thermal activation energies of GeSi dots and the wetting layers are 2.16 and 2.28 eV, respectively. The interdiffusion coefficient of the dots is about 40 times higher than that of wetting layers and the reasons were discussed. (C) 2001 American Institute of Physics

    Spatiotemporal Structure of Molecular Evolution of H5N1 Highly Pathogenic Avian Influenza Viruses in Vietnam

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    BackgroundVietnam is one of the countries most affected by outbreaks of H5N1 highly pathogenic avian influenza viruses. First identified in Vietnam in poultry in 2001 and in humans in 2004, the virus has since caused 111 cases and 56 deaths in humans. In 2003/2004 H5N1 outbreaks, nearly the entire poultry population of Vietnam was culled. Our earlier study (Wan et al., 2008, PLoS ONE, 3(10): e3462) demonstrated that there have been at least six independent H5N1 introductions into Vietnam and there were nine newly emerged reassortants from 2001 to 2007 in Vietnam. H5N1 viruses in Vietnam cluster distinctly around Hanoi and Ho Chi Minh City. However, the nature of the relationship between genetic divergence and geographic patterns is still unclear.Methodology/Principal FindingsIn this study, we hypothesized that genetic distances between H5N1 viruses in Vietnam are correlated with geographic distances, as the result of distinct population and environment patterns along Vietnam's long north to south longitudinal extent. Based on this hypothesis, we combined spatial statistical methods with genetic analytic techniques and explicitly used geographic space to explore genetic evolution of H5N1 highly pathogenic avian influenza viruses at the sub-national scale in Vietnam. Our dataset consisted of 125 influenza viruses (with whole genome sets) isolated in Vietnam from 2003 to 2007. Our results document the significant effect of space and time on genetic evolution and the rise of two regional centers of genetic mixing by 2007. These findings give insight into processes underlying viral evolution and suggest that genetic differentiation is associated with the distance between concentrations of human and poultry populations around Hanoi and Ho Chi Minh City.Conclusions/SignificanceThe results show that genetic evolution of H5N1 viruses in Vietnamese domestic poultry is highly correlated with the location and spread of those viruses in geographic space. This correlation varies by scale, time, and gene, though a classic isolation by distance pattern is observed. This study is the first to characterize the geographic structure of influenza viral evolution at the sub-national scale in Vietnam and can shed light on how H5N1 HPAIVs evolve in certain geographic settings

    An Analysis of How Interactive Technology Supports the Appreciation of Traditional Chinese Puppetry: A Review of Case Studies

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    From the perspective of safeguarding Chinese Cultural Heritage, this paper discusses how to enhance the appreciation of traditional Chinese puppetry through the support of interactive technology. The author analyses extensive, yet current case studies, based on the findings described in the interactive systems for puppetry performances and interactive technology for puppetry appreciation. The author summarises four aspects of how to enhance the appreciation of, and engagement with, traditional Chinese puppetry: (1) maintaining originality is necessary for the design phase; (2) it is crucial to explore how to use interactive technology in order to design a way for adults to appreciate this form of art; (3) it is also necessary to determine ways to support adult audiences in grasping the cultural significance and folk customs of traditional Chinese puppetry; and (4) the study’s further main research goals are to investigate ways to use emotional expressions, digital storytelling and other methods in conjunction with interactive technology to help multi-cultural users comprehend traditional Chinese puppetry

    Atrioventricular block of intraoperative device closure perimembranous ventricular septal defects; a serious complication

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    <p>Abstract</p> <p>Background</p> <p>Atrioventricular block (AVB) is a well-reported complication after closure of perimembranous ventricular septal defects (VSDs). To report the occurrence of AVB either during or following closure of perimembranous VSDs using a novel "hybrid" method involving a minimal inferior median incision and of intraoperative device closure of the perimembranous VSDs.</p> <p>Methods</p> <p>Between January 2009 and January 2011, patients diagnosed with perimembranous VSDs eligible for intraoperative device closure with a domestic occluder were identified. All patients were assessed by real-time transesophageal echocardiography (TEE) and electrocardiography.</p> <p>Results</p> <p>Of the 97 included patients, 94 were successfully occluded using this approach. Complete AVB occurred in only one case and one case of Mobitz type II AVB was diagnosed intraoperatively. In both patients, the procedure was aborted and the AVBs quickly resolved. Glucocorticosteroids were administered to another two patients who developed Mobitz type II AVB intraoperatively. Those two patients converted to Mobitz type I AVB 3 days and 5 days postsurgically. During the follow-up period (range, 6-24 months), one patient developed complete AVB 1 week following device insertion. Surgical device removal was followed by a rapid and complete recovery of atrioventricular conduction.</p> <p>Conclusions</p> <p>Intraoperative device closure of perimembranous VSDs with a domestic occluder resulted in excellent closure rates; however, AVB is a serious complication that can occur either during or any time after device closure of perimembranous VSDs. The technique described herein may reduce the incidence of perioperative AVB complications. Surgeons are encouraged to closely monitor all patients postsurgically to ensure AVB does not occur in their patients. Additional long-term data to better identify the prevalence and risk factors for AVB in treated patients are needed.</p

    Search for Kaluza-Klein Graviton Emission in ppˉp\bar{p} Collisions at s=1.8\sqrt{s}=1.8 TeV using the Missing Energy Signature

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    We report on a search for direct Kaluza-Klein graviton production in a data sample of 84 pb1{pb}^{-1} of \ppb collisions at s\sqrt{s} = 1.8 TeV, recorded by the Collider Detector at Fermilab. We investigate the final state of large missing transverse energy and one or two high energy jets. We compare the data with the predictions from a 3+1+n3+1+n-dimensional Kaluza-Klein scenario in which gravity becomes strong at the TeV scale. At 95% confidence level (C.L.) for nn=2, 4, and 6 we exclude an effective Planck scale below 1.0, 0.77, and 0.71 TeV, respectively.Comment: Submitted to PRL, 7 pages 4 figures/Revision includes 5 figure

    Measurement of the average time-integrated mixing probability of b-flavored hadrons produced at the Tevatron

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    We have measured the number of like-sign (LS) and opposite-sign (OS) lepton pairs arising from double semileptonic decays of bb and bˉ\bar{b}-hadrons, pair-produced at the Fermilab Tevatron collider. The data samples were collected with the Collider Detector at Fermilab (CDF) during the 1992-1995 collider run by triggering on the existence of μμ\mu \mu and eμe \mu candidates in an event. The observed ratio of LS to OS dileptons leads to a measurement of the average time-integrated mixing probability of all produced bb-flavored hadrons which decay weakly, χˉ=0.152±0.007\bar{\chi} = 0.152 \pm 0.007 (stat.) ±0.011\pm 0.011 (syst.), that is significantly larger than the world average χˉ=0.118±0.005\bar{\chi} = 0.118 \pm 0.005.Comment: 47 pages, 10 figures, 15 tables Submitted to Phys. Rev.

    A Bayesian Model for Detection of Highorder Interactions Among Genetic Variants in Genome-Wide Association Studies

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    Background: A central question for disease studies and crop improvements is how genetics variants drive phenotypes. Genome Wide Association Study (GWAS) provides a powerful tool for characterizing the genotypephenotype relationships in complex traits and diseases. Epistasis (gene-gene interaction), including high-order interaction among more than two genes, often plays important roles in complex traits and diseases, but current GWAS analysis usually just focuses on additive effects of single nucleotide polymorphisms (SNPs). The lack of effective computational modelling of high-order functional interactions often leads to significant under-utilization of GWAS data. Results: We have developed a novel Bayesian computational method with a Markov Chain Monte Carlo (MCMC) search, and implemented the method as a Bayesian High-order Interaction Toolkit (BHIT) for detecting epistatic interactions among SNPs. BHIT first builds a Bayesian model on both continuous data and discrete data, which is capable of detecting high-order interactions in SNPs related to case—control or quantitative phenotypes. We also developed a pipeline that enables users to apply BHIT on different species in different use cases. Conclusions: Using both simulation data and soybean nutritional seed composition studies on oil content and protein content, BHIT effectively detected some high-order interactions associated with phenotypes, and it outperformed a number of other available tools. BHIT is freely available for academic users at http://digbio.missouri.edu/BHIT/

    Introgression of Chromosome 3Ns from Psathyrostachys huashanica into Wheat Specifying Resistance to Stripe Rust

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    Wheat stripe rust is a destructive disease in the cool and humid wheat-growing areas of the world. Finding diverse sources of stripe rust resistance is critical for increasing genetic diversity of resistance for wheat breeding programs. Stripe rust resistance was identified in the alien species Psathyrostachys huashanica, and a wheat- P. huashanica amphiploid line (PHW-SA) with stripe rust resistance was reported previously. In this study, a P. huashanica 3Ns monosomic addition line (PW11) with superior resistance to stripe rust was developed, which was derived from the cross between PHW-SA and wheat J-11. We evaluated the alien introgressions PW11-2, PW11-5 and PW11-8 which were derived from line PW11 for reaction to new Pst race CYR32, and used molecular and cytogenetic tools to characterize these lines. The introgressions were remarkably resistant to CYR32, suggesting that the resistance to stripe rust of the introgressions thus was controlled by gene(s) located on P. huashanica chromosome 3Ns. All derived lines were cytologically stable in term of meiotic chromosome behavior. Two 3Ns chromosomes of P. huashanica were detected in the disomic addition line PW11-2. Chromosomes 1B of substitution line PW11-5 had been replaced by a pair of P. huashanica 3Ns chromosomes. In PW11-8, a small terminal segment from P. huashanica chromosome arm 3NsS was translocated to the terminal region of wheat chromosomes 3BL. Thus, this translocated chromosome is designated T3BL-3NsS. These conclusions were further confirmed by SSR analyses. Two 3Ns-specific markers Xgwm181 and Xgwm161 will be useful to rapidly identify and trace the translocated fragments. These introgressions, which had significant characteristics of resistance to stripe rust, could be utilized as novel germplasms for wheat breeding

    Amiloride Enhances Antigen Specific CTL by Faciliting HBV DNA Vaccine Entry into Cells

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    The induction of relatively weak immunity by DNA vaccines in humans can be largely attributed to the low efficiency of transduction of somatic cells. Although formulation with liposomes has been shown to enhance DNA transduction of cultured cells, little, if any, effect is observed on the transduction of somatic tissues and cells. To improve the rate of transduction, DNA vaccine delivery by gene gun and the recently developed electroporation techniques have been employed. We report here that to circumvent requirement for such equipment, amiloride, a drug that is prescribed for hypertension treatment, can accelerate plasmid entry into antigen presenting cells (APCs) both in vitro and in vivo. The combination induced APCs more dramatically in both maturation and cytokine secretion. Amiloride enhanced development of full CD8 cytolytic function including induction of high levels of antigen specific CTL and expression of IFN-γ+perforin+granzymeB+ in CD8+ T cells. Thus, amiloride is a facilitator for DNA transduction into host cells which in turn enhances the efficiency of the immune responses
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