Mayer brackets and solvability of PDEs - II

For the Spencer -cohomologies of a symbolic system we construct a spectral sequence associated with a subspace. We calculate the sequence for the systems of Cohen-Macaulay type and obtain a reduction theorem, which facilitates computation of -cohomologies by reducing dimension of the system. Using this algebraic result we prove an efficient compatibility criterion for a system of two scalar non-linear PDEs on a manifold of any dimension in terms of (generalized) Mayer brackets.

     

Enhanced mechanical property of chitosan via blending with functional poly(ε-caprolactone)

Blends of chitosan and poly(ε-caprolactone-co-2-oxepane-1,5-dione) (PCO) were fabricated by solvent casting technique using 77% acetic acid as the cosolvent. The interactions between chitosan and PCO were analyzed by Fourier transform infrared spectroscopy, nuclear magnetic resonance, and differential scanning calorimetry. The miscibility became poorer with increase of PCO from 50% to 75%, which was supported by the Flory–Huggins interaction parameter and crystallinity of PCO. According to X-ray pattern, crystallinity of CS became weaker when PCO content was improved. Results indicated that there existed stronger interactions in comparison with PCL/CS blends. Therefore, the addition of functional polyester PCO made the brittle chitosan ductile. The elongation was significantly prolonged to 21.60 ± 4.92% with the break stress maintaining about 32 MPa, better than that of PCL blends. The degradation behavior showed slower degradation rate compared with pure CS and the morphology was illustrated by scanning electron microscopy. © 2012 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2013     

Compatible stability study of panax notoginseng saponin injection (xueshuantong®) in combination with 47 different injectables

Panax Notoginseng Saponin (PNS) injection (Xueshuantong®, XST) plays an important role in acute and chronic treatment of cardiovascular disease in China. XST, a freeze‐dried powder injection of PNS, contains ginsenosides, Rg1, Rb1, Re, Rd. and notoginsenoside, R1. Study of the stability of herbal medicine injections is limited. The degradation products may contribute to adverse drug reactions (ADRs). The stability kinetics and degradation mechanisms of the five ingredients of PNS in XST injection were systematically explored in aqueous solution. The compatible stability of XST injection in combination with 47 injectables was evaluated using biophysical analysis. A principal components analysis model provided a good clustering result after compatibility. The degradation of the five ingredients in aqueous solution was found to be acid, temperature, oxidation and trivalent ion‐dependent. All ingredients were much more stable in XST injection than in aqueous solutions. Nine degradation products were identified by adopting LC‐Q‐TOF/MS. Standards exceeding the osmotic pressure and/or particle size were found to be the probable causes of the ADR, which were related to drug combination. To minimize the risk of ADRs, drug combinations should be avoided until the complicated chemical matrices of the Chinese medicine injections are more clearly understood. Copyright © 2016 John Wiley & Sons, Ltd.     

动态力学分析方法在塑木复合材料研究中的应用

阐述了动态力学分析(DMA)方法在塑木复合材料研究中的应用现状,重点介绍了国内外运用动态力学方法分析塑木复合材料界面相容性的问题。使用各类改性剂改善塑木复合材料的界面相容性后,塑木复合材料的刚性增加,其储能模量比相容性差的复合材料要高。当用DMA的损耗角正切(tanδ)来分析塑木复合材料的界面相容性时,我们可以得出如下结论:对于填料纤维和塑料之间具有良好界面相容性的复合材料,由于强的界面粘结作用可以限制填料-基体界面链段的运动,往往使得tanδ的振幅值降低,而其对应的温度,即玻璃化转变温度(Tg)将移动到更高的温度,并且复合材料界面增强指数和弛豫过程的活化能越大,界面粘结强度越大。     

Bounds on the value of information in uncertain decision problems II†

In most stochastic decision problems one has the opportunity to collect information that would partially or totally eliminate the inherent uncertainty. One wishes to compare the cost and value of such information in terms of the decision maker's preferences to determine an optimal information gathering plan. The calculation of the value of information generally involves oneor more stochastic recourse problems as well as one or more expected value distribution problems. The difficulty and costs of obtaining solutions to these problems has led to a focus on the development of upper and lower bounds on the various subproblems that yield bounds on the value of information. In this paper we discuss published and new bounds for static problems with linear and concave preference functions for partial and perfect information. We also provide numerical examples utilizing simple production and investment problems that illustrate the calculations involved in the computation of the various bounds and provide a setting for a comparison of the bounds that yields some tentative guidelines for their use. The bounds compared are the Jensen's Inequality bound,the Conditional Jensen's Inequality bound and the Generalized Jensen and Edmundson-Madansky bounds.     

A homogeneous assay principle for universal substrate quantification via hydrogen peroxide producing enzymes

H₂O₂ is a widely occurring molecule which is also a byproduct of a number of enzymatic reactions. It can therefore be used to quantify the corresponding enzymatic substrates. In this study, the time-resolved fluorescence emission of a previously described complex consisting of phthalic acid and terbium (III) ions (PATb) is used for H₂O₂ detection. In detail, glucose oxidase and choline oxidase convert glucose and choline, respectively, to generate H₂O₂ which acts as a quencher for the PATb complex. The response time of the PATb complex toward H₂O₂ is immediate and the assay time only depends on the conversion rate of the enzymes involved. The PATb assay quantifies glucose in a linear range of 0.02–10 mmol L⁻¹, and choline from 1.56 to 100 μmol L⁻¹ with a detection limit of 20 μmol L⁻¹ for glucose and 1.56 μmol L⁻¹ for choline. Both biomolecules glucose and choline could be detected without pretreatment with good precision and reproducibility in human serum samples and infant formula, respectively. Furthermore, it is shown that the detected glucose concentrations by the PATb system agree with the results of a commercially available assay. In principle, the PATb system is a universal and versatile tool for the quantification of any substrate and enzyme reaction where H₂O₂ is involved.     

高管个人特征对股权激励模式选择的影响研究

上市公司股权激励模式的选择问题一直受社会各界关注。本文利用2006年到2017年期间实施股权激励的上市公司数据,研究了高管个人特征如何对股权激励模式的选择产生影响。结果表明,被激励高管的个人特征如高管年龄、任期、学历与社会资本显著影响公司股权激励模式的选择,年龄越大、任期越久、学历越高、社会资本越丰富的高管,公司更倾向选择限制性股票激励模式;男性高管越多的公司,越倾向选择股票期权激励模式,然而性别对其影响并不显著。本文在经过一系列的稳健性和内生性检验后,研究结论依然成立。本文研究结果丰富了股权激励相关理论,并为上市公司科学合理地选择股权激励模式提供参考。     

基于数值分布的激励型综合评价方法

针对激励评价中的等级划分问题,本文提出了一种基于数值分布的等级划分方法,相比于现有的等级划分方法,该方法能够综合考虑数值分布情况来划分等级,并结合本文提出的等级划分法对密度算子进行拓展,提出了一种基于数值分布的激励型综合评价方法。首先本文从数值分布的角度提出了一种新的等级划分方法,从而得出各等级区间的等级区间分界点;其次确定等级系数,并结合指标值和等级区间分界点给出各指标的权向量,给出一种不需要进行归一化处理的等级权向量确定方法,该方法能够较好的解决归一化处理带来的不公平性;再次根据密度算子思想对评价数据进行集结得出评价结果;最后通过一个算例对该方法进行验证,结果表明该方法可以实现对被评价对象科学激励的作用。该方法尤其适用于企业员工激励、省市综合排名、高校人才选拔等问题。     

一种求解序列二次规划结合信赖域的多维滤子算法

求解非线性规划问题最有效的方法之一为序列二次规划。但是,由于序列二次规划结合信赖域时,会出现可能无解的情况(即不相容性)。而本文针对不相容性提出了一类序列二次规划结合信赖域的多维相容滤子算法。首先,本文根据一般文献中提及的方法对其约束条件引进参数变量,对其目标函数加以惩罚,即实行了可行化处理(也就是无需可行性恢复阶段),从而克服了不相容性。其次,本文提出了多维滤子条件来对迭代步进行选择性的接受,从而避免了传统二维滤子算法的严格条件,使得对迭代步的接受程度大大的放松。最后针对可能出现的maratos效应,我们通过二阶校正策略提出了一种修改后的多维滤子算法。同时,在一定的假设条件下算法具有全局收敛性。     

Development and evaluation of cyclodextrin complexed hydroxyapatite nanoparticles for preferential albumin adsorption

Our study focuses on the incorporation of β-CD into the HA structure, its effects on the phase of HA and the biological responses to proteins and blood cells. Hydroxyapatite (HA) containing levels of β-cyclodextrin (β-CD) of upto 0.9 wt% has been produced by co-precipitation method. The complexes were analyzed by X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared (FT-IR) spectroscopy, thermal gravimetric analysis (TG) and differential scanning analysis (DSC) methods. The size of the complexes as analyzed using DLS (dynamic light scattering) was between 150 nm and 350 nm. The results show that an increase in concentration of β-CD in the prepared samples that leads to an increase in hydrophobicity seems to promote an affinity for albumin adsorption. The PAGE results were substantiated by Lowry measurements and the results reveal that the H2 (containing 0.7 wt% β-CD) sample shows around 40% increase in albumin adsorption when compared to the H1 (containing 0.5 wt% β-CD) sample. The preferential adsorption of albumin has not been demonstrated in vivo. The ability to design particles that can preferentially interact with particular protein can obtain desired targeting effects. So the results indicate that HA/β-CD complexes have immense potential in targeted delivery of drugs. The in vivo potential of the developed samples was further confirmed in vitro by the results of cell aggregation and haemolytic activity.