Rotational viscosity of uniaxial molecules

Non-equilibrium molecular dynamics (NEMD) are used to calculate the vortex or rotational viscosity of fluids composed of uniaxial molecules. It is shown that the NEMD homogeneous spin flow algorithm proposed by Edberg, R., Evans, D. J., and Moriss, G. P., 1987, Molec. Phys., 62, 1357 considerably underestimates the vortex viscosity. A modified version of this algorithm is proposed and applied to liquid chlorine and nitrogen. The results are in good agreement with previous work using equilibrium or other NEMD methods, and also show that at high spin rates the vortex viscosity decreases with increase in magnitude of the external torque used to drive the spin flow.     

THE HADAMARD INEQUALITY FOR CONVEX FUNCTION VIA FRACTIONAL INTEGRALS

In this paper, we establish several inequalities for some differantiable mappings that are connected with the Riemann-Liouville fractional integrals. The analysis used in the proofs is fairly elementar...     

On the role of the definition of potential models in Gibbs ensemble phase equilibria simulations of the H2S-pentane mixture

The effect of treating explicitly the coulombic and polarization interactions is investigated through the calculation of the coexistence curve of the pentane-H₂S binary mixture. In this work, potential models have been developed for hydrogen sulphide and pentane, which include electrostatic sites—estimated from ab initio calculations—and polarizable sites—estimated from experimental data—in addition to Lennard-Jones sites. Compared to existing models, these new models have the same number of fitting parameters to experimental thermodynamic data. They are shown to correctly describe the coexistence curve of the pure compounds. When applied to the case of mixtures, together with Lorentz-Berthelot combining rules, they allow one to obtain a more accurate prediction of the coexisting compositions of the mixture. Furthermore, it is shown that the interaction energy in this kind of mixture cannot be properly described by using effective potential models usually considered for pure compounds.     

在硅胶表面制备牛血红蛋白分子印迹聚合物

采用表面印迹法, 以乙烯基三甲氧基硅烷修饰的硅胶为载体, 丙烯酰胺为功能单体, N,N-亚甲基双丙烯酰胺为交联剂, 并将改性聚乙烯醇(PVA)作为辅助识别聚合物链(ARPCs)引入聚合体系中, 制备了牛血红蛋白分子印迹聚合物(MIP). 实验使用红外光谱分析了改性PVA的结构特征, 用扫描电镜(SEM)观察MIP的表面形貌, 考察了ARPCs的含量对MIP吸附性能的影响. 吸附动力学实验研究表明, 聚合体系中ARPCs的引入使MIP对模板牛血红蛋白(BHb)的吸附量明显提高|十二烷基磺酸钠-聚丙烯酰胺凝胶电泳(SDS-PAGE)结果显示, MIP对BHb的特异性吸附能力明显提高.     

TRANSFER MECHANISM OF QUININE DRUG ACROSS THE OIL/WATER (O/W) INTERFACE

The transfer phenomena of quinine drug at the aqueous 1,2- dichloroethane (DCE)interface have been studied by the current- scanning polarography. The relationships be-tween the wave height and pH of aqueous phase, concentration of quinine as well as therate of water drop are discussed. The effect of supporting electrolyte, buffer solution andthe nature of organic solvent on the polarographic wave is studied. The transfer char-acteristics of quinine in aqueous phase and in organic phase are compared, The mono- pro-tonated and diprotonated quinines can both transfer at the interface so as to produce twopolarographic waves. The transfer process of quinine at the interface is simultaneouslycontrolled by diffusion and reestablishment of the disturbed protonated equilibrium ofquinine. A further investigation is made by chronopotentiometry. On the basis of thetheoretical analysis, the formulae of the limiting current are derived and discussed. Thetheoretical results are in agreement with the experimental ones.     

Gamma induced changes in Makrofol/CdSe nanocomposite films

We applied an ex-situ casting procedure to prepare a nanocomposite (NCP) from Makrofol polycarbonate (PC) and CdSe nanoparticles. The CdSe nanoparticles were prepared by a thermolysis procedure in the presence of N₂ gas flow. Rietveld refinement of x-ray data illustrated that the CdSe adopts a cubic zinc blend structure of 6.057 Å lattice parameter and 2 nm typical grain size. Samples from the prepared NCP were exposed to γ dosages (20 kGy-250 kGy). The modifications induced in the NCP films owing to γ dosages have been studied. The γ irradiation (50 kGy-250 kGy) causes crosslinks that reduce the optical bandgap from 4.15 eV to 3.81 eV, associated with an increase in dielectric parameters and refractive index. This is attributed to an increase in the mass fraction of the disordered regions as specified by x-ray diffraction. The PC-CdSe NCP was found to have a reaction to color modification which makes it suitable for saleable reproduction on a printing press.     

Are signal intensity and homogeneity useful parameters for distinguishing between benign and malignant soft tissue masses on MR images?: Objective evaluation by means of texture analysis

Objectives

To objectively identify possible differences in the signal characteristics of benign and malignant soft tissue masses (STM) on magnetic resonance (MR) images by means of texture analysis and to determine the value of these differences for computer-assisted lesion classification.

Method

Fifty-eight patients with histologically proven STM (benign, n=30; malignant, n=28) were included. STM texture was analyzed on routine T1-weighted, T2-weighted and short tau inversion recovery (STIR) images obtained with heterogeneous acquisition protocols. Fisher coefficients (F) and the probability of classification error and average correlation coefficients (POE+ACC) were calculated to identify the most discriminative texture features for separation of benign and malignant STM. F>1 indicated adequate discriminative power of texture features. Based on the texture features, computer-assisted classification of the STM by means of k-nearest-neighbor (k-NN) and artificial neural network (ANN) classification was performed, and accuracy, sensitivity and specificity were calculated.

Results

Discriminative power was only adequate for two texture features, derived from the gray-level histogram of the STIR images (first and 10th gray-level percentiles). Accordingly, the best results of STM classification were achieved using texture information from STIR images, with an accuracy of 75.0% (sensitivity, 71.4%; specificity, 78.3%) for the k-NN classifier, and an accuracy of 90.5% (sensitivity, 91.1%; specificity, 90.0%) for the ANN classifier.

Conclusion

Texture analysis revealed only small differences in the signal characteristics of benign and malignant STM on routine MR images. Computer-assisted pattern recognition algorithms may aid in the characterization of STM, but more data is necessary to confirm their clinical value.