Degradation induced variation of LC transition of poly(n-undecyl isocyanate)

The first-order thermal transitions including side-chain melting, crystal-LC, biphasic chimney-like, and isotropic transitions of poly(n-undecyl isocyanate) (PUDIC) were investigated by varying its thermal history. After annealing at 140 °C for different periods of time, it leads to different degrees of backbiting degradation into n-undecyl isocyanurate trimer which behaves as a solvent for the rest non-degraded/rigid PUDIC to change into a lyotropic LC from thermotropic transition. Based on the degree of degradation, various amounts of trimers are present and the PUDIC demonstrates different types of thermal transitions found in DSC thermograms due to the variation of the non-degraded PUDIC concentration in solvent trimers. Finally, a phase diagram includes all types of crystallines, LC, and isotropic regions can be drawn according to the DSC thermograms.     

基于多软件融合方法的真核生物基因启动子预测

基于多个软件的预测结果,提出了一种融合方法(ComPromoter)提高真核生物基因启动子的预测精度.ComPromoter以ProKey、FirstEF和Eponine等软件对启动子的预测结果为基础,融合了可用于启动子识别的多个特征(包括ProKey预测结果中真阳性和假阳性的出现频率随投票距离以及预测分值变化的统计特征),并利用支持向量机构建了启动子预测模型.在人类ENCODE区域测试数据集上测试的结果显示,ComPromoter的Pearson相关系数CC值高于所融合的单个启动子预测软件.     

The effect of F substitution on the magnetic properties of Nd−Fe−B based compounds

Various efforts are currently undertaken to raise the relatively low Curie temperature of the otherwise promising Nd?Fe?B type permanent magnet material. The substitution of Fe by several elements was found to increaseT _c, which, on the other hand, can be accompanied by a reduction of the magnetocrystalline anistropy. In the present paper a systematic Mössbauer study was carried out, using Co, Ni, Al, Si and Ga as substituents. The specific influence of each element upon the magnetic properties is attributed to its preference for entering a certain Fe lattice site. Simple atomic size considerations are proved to be insufficient for explaining the preferred occupation observed experimentally. Obviously the local electronic structure has to be studied more carefully. Finally, the interplay between magnetism and metallurgy (particularly the formation of precipitations), is found to be of some importance.     

Flexural behavior of strain-softening solids

The flexural behavior of a beam is investigated in an attempt to establish a correlation between the tensile and bending properties of strain-softening solids. Given the complete uniaxial stress—strain relations, including the post-peak tension-softening portion, it is possible to predict the flexural behavior in moment—curvature and load—deflection relations. The results indicate that strain-softening gives rise to enhanced bending strength in agreement with experimental data. Conversely, given the bending responses together with the softening characteristics the complete tensile behavior can be determined. Since bending experiments are easier to perform than uniaxial tensile tests, this well-defined correlation provides a feasible means to obtain the entire tensile behavior of strain-softening solids such as concrete, rocks and ceramics.     

Textile‐based Electrochemical Sensing: Effect of Fabric Substrate and Detection of Nitroaromatic Explosives

This study examines the influence of textile substrates upon the behavior of wearable screen‐printed electrodes and demonstrates the attractive sensing properties of these sensors towards the detection of nitroaromatic explosives. Compared to electrodes printed on common cotton or polyester substrates, GORE‐TEX‐based electrochemical sensors display reproducible background cyclic voltammograms, reflecting the excellent water‐repellant properties of the GORE‐TEX fabric. The wetting properties of different printed textile electrodes are elucidated using contact angle measurements. The influence of laundry washing and mechanical stress is explored. The GORE‐TEX‐based printed electrodes exhibit favorable detection of 2,4‐dinitrotoluene (DNT) and 2,4,6‐trinitrotoluene (TNT) explosives, including rapid detection of DNT vapor.     

Protein identification from two-dimensional gel electrophoresis by connecting ZipTip with a home-assembled nanoflow system

Mass spectrometry (MS) is a powerful technique for protein identification in proteomic research. Two-dimensional gel electrophoresis (2-DE) combined with MS is a significant method for protein separation and identification. For protein identification, peptide sequencing is usually carried out by an effective but expensive nano-flow liquid chromatographic system combined to tandem mass spectrometry (MS/MS). However, protein identification based on such method is time-consuming, and contamination may occur as a result of column overloading. In this study, we establish an alternative nanoscale system for protein identification using MS/MS. The system consists of several devices that can be purchased from commercial sources and can be connected to an electrospray ionization quadrupole-time of flight (ESI-Q-TOF) MS in order to analyze proteins from 2D gels. This inexpensive strategy provides an attractive alternative method for rapid identification of proteins using a nanospray source. In addition, the device is disposable so that contamination is avoided. It is shown that peptide sequencing based on this device using ESI-Q-TOF MS is accomplished within 10 min.     

Application of sugaring-out extraction for the determination of sulfonamides in honey by high-performance liquid chromatography with fluorescence detection

A simple sugaring-out assisted liquid-liquid extraction method combined with high-performance liquid-chromatography with fluorescence detection (HPLC-FL) was developed for the extraction and determination of sulfonamides in honey. Sample preparation consisted of acid hydrolysis to release sugar-bound sulfonamides. After derivatization with fluorescamine, the derivatives were partitioned into the organic layer under the honey (sugar)/water/acetonitrile system. The clear organic extract obtained by centrifugation could be injected into the HPLC system either directly or after dilution. Linearity was obtained with the coefficient of determination (R(2)) higher than 0.998 from 2 to 200 ng/mL. Under the optimal conditions, recoveries were determined for honey fortified at three levels (5, 20, and 100 ng/g) were 80.9-99.6% with coefficients of variation of 0.3-4.4%. Limits of detection for the sulfonamides studied were found to range from 0.6 to 0.9 ng/g.     

BIFURCATION ANALYSIS IN A GENERALIZED FRICTION MODEL WITH TIME-DELAYED FEEDBACK

In this paper, we consider a generalized model of the two friction models, both of which have two different types of control forces with time-delayed feedback proposed by Ashesh Sara et al. By taking the time delay as the bifurcation parameter, we discuss the local stability of the Hopf bifurcations. Under some condition, the generalized model harbors a phenomenon that the equilibrium may undergo finite switches from stability to instability to stability and finally become unstable. By applying the method introduced by Faria and Magalhaes, we compute the normal form on the center manifold to determine the direction and stability of the Hopf bifurcations. Numerical simulations are carried out and more than one periodic solutions may exist according to the bifurcation diagram given by BIFTOOL. Finally a brief conclusion is presented.     

An integrated inventory model with quality improvement and two-part credit policy

Trade credit financing plays a vital role in current business operations. Vendors extend payment dates to encourage sales, and buyers are not required to pay immediately after receiving products. This is equivalent to receiving a price reduction. Besides, buyers reduce their need for capital from bank loans. In addition, a number of defective products are produced during the production process. The number of defective items influences the on-hand inventory levels of buyers, service levels, and frequency of orders. To ensure that the analysis incorporates a realistic production environment, we developed an integrated inventory model with a two-part trade credit and considered an imperfect production process that can be improved by capital investment. The objective was to determine the optimal ordering, shipping, and quality improvement policies to maximize joint total profit. An iterative algorithm was established to determine the optimal strategy. Furthermore, a sensitivity analysis was conducted to examine the effects of changing parameter values on the optimal solution.