Low-temperature fabrication and photocatalytic activity of clustered TiO2 particles formed on glass fibers

Clustered anatase phase TiO₂ particles were uniformly formed on the surface of glass fibers by a liquid phase deposition (LPD) method at 60 °C using TiF₄ and H₃BO₃ as the precursors. The clustered TiO₂ particles deposited on the glass fibers and as a photocatalyst these particles not only have a larger surface area than TiO₂ thin films, but also can avoid the disadvantages of using TiO₂ powders encountered in air purification or water treatment. The photocatalytic activity of the sample was evaluated by the photocatalytic oxidation of nitrogen monoxide (NO) in the gaseous phase. The deposition conditions and chemical composition of the clustered TiO₂ particles were discussed. It was found that the clustered TiO₂ particles that formed on the glass fibers obviously showed photocatalytic activity without high-temperature calcination. A formation mechanism was proposed to account for the formation of TiO₂ clustered morphology on the glass fibers.     

Noncontrast dynamic MRA in intracranial arteriovenous malformation (AVM), comparison with time of flight (TOF) and digital subtraction angiography (DSA)

Digital subtraction angiography (DSA) remains the gold standard to diagnose intracranial arteriovenous malformations (AVMs) but is invasive. Existing magnetic resonance angiography (MRA) is suboptimal for assessing the hemodynamics of AVMs. The objective of this study was to evaluate the clinical utility of a novel noncontrast four-dimensional (4D) dynamic MRA (dMRA) in the evaluation of intracranial AVMs through comparison with DSA and time-of-flight (TOF) MRA. Nineteen patients (12 women, mean age 26.2±10.7 years) with intracranial AVMs were examined with 4D dMRA, TOF and DSA. Spetzler-Martin grading scale was evaluated using each of the above three methods independently by two raters. Diagnostic confidence scores for three components of AVMs (feeding artery, nidus and draining vein) were also rated. Kendall's coefficient of concordance was calculated to evaluate the reliability between two raters within each modality (dMRA, TOF, TOF plus dMRA). The Wilcoxon signed-rank test was applied to compare the diagnostic confidence scores between each pair of the three modalities. dMRA was able to detect 16 out of 19 AVMs, and the ratings of AVM size and location matched those of DSA. The diagnostic confidence scores by dMRA were adequate for nidus (3.5/5), moderate for feeding arteries (2.5/5) and poor for draining veins (1.5/5). The hemodynamic information provided by dMRA improved diagnostic confidence scores by TOF MRA. As a completely noninvasive method, 4D dMRA offers hemodynamic information with a temporal resolution of 50-100 ms for the evaluation of AVMs and can complement existing methods such as DSA and TOF MRA.     

Investigation on the oxidation of aryl oxiranylmethanols and the synthesis of 2-aryl-N-thiazolyl-oxirane-2-carboxamides as glucokinase activators

RuCl₃/NaIO₄-initiated oxidation of oxiranemethanols was investigated, and two products, oxirane-2-carboxylic acid and (5′-oxotetrahydrofuran-3-yl)acetic acid, were obtained in variant ratios. The product structures were determined and a tentative mechanism involving oxidation-rearrangement-oxidation process was proposed. Glucokinase enzymatic assay revealed that oxiranecarboxamides 4a-c retained moderate GK activation potency with amide 4a showing an EC₅₀ value of 584 nM and a high activation fold of 3.14. However, (5′-oxotetrahydrofuran-3-yl)acetamide 11a is inactive. This study not only provided an alternative protocol to access (5′-oxotetrahydrofuran-3-yl)acetic acid analogs, but also yielded nanomolar GA activators (esp. 4a) for further structure-activity relationship study.     

Oscillation criteria of a class of fourth order differential equations

In the present paper, we consider the oscillation of a class of self‐adjoint fourth order differential equation. Some oscillation and non‐oscillation criteria on a perturbation equation of Euler differential equation are given. In particular, we find the exact value of a constant in some oscillation criteria, which has answered the open problem presented by Do?lý in 2004. Copyright © 2011 John Wiley & Sons, Ltd.     

福寿螺的生活习性及养殖试验

本文介绍福寿螺的外部形态,生活习性,人工繁殖方法和越冬。     

基于利润—CVaR的期权契约供应链协调

文章以一个风险厌恶销售商与风险中性供应商所组成的两级供应链为背景,以条件风险价值(CVaR)和期望利润的加权平均作为销售商的决策目标,对期权契约下销售商的订购策略及供应链协调问题进行了研究,并对比分析了销售商以CVaR为目标时的情形。在给出销售商在不同风险厌恶程度下的最优订购策略后,文章进一步给出了供应链相应的协调条件,并分析了此时期权权利金,销售商的风险厌恶程度和期望利润权重等参数对供销双方收益的影响,发现“利润-CVaR”法下销售商的风险厌恶程度对供销双方利润的影响与CVaR法下的情况有所不同,但权利金依然起到了分配整体供应链利润的作用,且销售商期望利润权重的增加会降低自身收益水平而提高供应商利润。最后,文章通过数值模拟的方式对上述结论进行了验证。     

Noise in a Small Genetic Circuit that Undergoes Bifurcation

Based on the consideration of Boolean dynamics, it has been hypothesized that cell types may correspond to alternative attractors of a gene regulatory network. Recent stochastic Boolean network analysis, however, raised the important question concerning the stability of such attractors. In this paper a detailed numerical analysis is performed within the framework of Langevin dynamics. While the present results confirm that the noise is indeed an important dynamical element, the cell type as represented by attractors can still be a viable hypothesis. It is found that the stability of an attractor depends on the strength of noise related to the distance of the system to the bifurcation point and it can be exponentially stable depending on biological parameters.     

Optimal adaptive generalized Pólya urn design for multi-arm clinical trials

A class of optimal adaptive multi-arm clinical trial designs is proposed based on an extended generalized Pólya urn (GPU) model. The design is applicable to both the qualitative and quantitative responses and achieves, asymptotically, some pre-specified optimality criterion. Such criterion is specified by a functional of the response distributions and is implemented through the relationship between the design matrix and its first eigenvector. The asymptotic properties of the design are studied using the existing methods on GPU. Some examples for commonly used clinical designs are given as illustration.     

类拟b-距离空间中几类循环压缩映射不动点定理

在类拟b-距离空间中建立了几种类型的循环映射的不动点定理,所得结果改进并统一了前人文献中的主要结果.而且,给出了几个非平凡的例子突出了其主要结果的优越性.