Electrochemically partitioned assembly of organosulfur monolayers and nanoparticles

Partitionally assembled organosulfur monolayers were prepared by using an electrochemically assisted assembly method on gold films that were preseparated into two regions insulated from each other. Cyclic voltammetry (CV) and X-ray photoelectron spectroscopy (XPS) were employed to characterize the n-dodecanethiol (DDT) and the 11-mercaptoundecanoic acid (MUA) monolayers, which were separately assembled on different substrate regions. CV results indicated that both the DDT- and MUA-coated gold electrodes showed a blocking property toward the negatively charged redox probe Fe(CN)6(3-). However, when positively charged Ru(NH3)6(3+) was used as the redox probe, the MUA- and DDT-modified electrodes showed quasireversible and blocking CV features, respectively. These phenomena were attributed to different interactions between the negatively charged MUA surface and the negatively or positively charged redox probes. XPS spectra obtained on the MUA modified region exhibited an O(1s) peak and a small discrete C(1s) peak, which arose from the oxygen and the carbon atoms in the carboxylic acid groups, respectively. For the DDT-modified region, these two peaks were absent. CV and XPS experimental results provided strong evidence that different SAMs were selectively deposited onto different regions of the preexisting patterns of the substrate by electrochemically partitioned assembly. The partitionally assembled sulfur-based monolayers with different terminal groups were used to form location-selective nanoparticle assemblies. This electrochemically partitioned assembly technique has great potential in controllable constructions of molecular layers and nanostructures on different surface microarchitectures that are closely integrated on one substrate but insulated from each other.     

Tricritical phenomena in quasi-ternary mixtures of water + n-decane + n-undecane + tert-butanol

Coexistence curves for the quasi-ternary system of water + n-decane + n-undecane + tert-butanol have been determined by measurements of the refractive index in three coexisting liquid phases. The binary mixtures of n-decane + n-undecane constructed the quasi-pure components in which the mass fraction beta of n-decane controls the approach to the tricritical point. The coexistence curves can be fitted to Scott's extended theory and can be extrapolated to a tricritical point at (44.1 +/- 0.3) degrees C and beta = 0.77 +/- 0.02 corresponding to an average n-alkane-carbon number of 10.19 +/- 0.02. The nonclassical critical amplitude ratio has been confirmed to be 4-5% smaller than the classical value, which is consistent with Fisher's prediction.     

Adjoint transform of Willmore surfaces in

Using moving frame method, we study the Möbius geometry of a pair of conformally immersed surfaces in . Two new invariants θ and ρ associated with them arise naturally as well as the notion of touch and co-touch. As an application, adjoint transform is defined for any Willmore surface in . It always exists locally, hence generalizes known duality theorems of Willmore surfaces. Finally we characterize a pair of adjoint Willmore surfaces in terms of harmonic map.     

Synthesis of functionalized quinolines via Ugi and Pd-catalyzed intramolecular arylation reactions

Two types of quinoline scaffolds were constructed in a combinatorial format via the Ugi four-component reaction (U-4CR) and Pd-catalyzed intramolecular arylation reaction. The scope of this two-step synthetic sequence was examined from commercially available and synthetically accessible starting materials.     

Design and synthesis of a tetracyclic pyrimidine-fused benzodiazepine library

Method development for a heterocyclic library which entails novel scaffolds of benzodiazepines fused with various heterocycles, such as pyrimidines, indolines, and tetrahydroquinolines, was accomplished. The new synthetic strategy is based on an electrophilic cyclization reaction involving an iminium intermediate formed by the corresponding aminopyrimidine with a carbonyl compound to give the desired heterocycles in high yields. Subsequent replacement of the chloro group in the resulted structures with a nucleophile, such as boronic acids, amines, alcohols and thiols, led to a library of privileged compounds with up to eight accessible diversity points.     

Fabrication of monodisperse colloidal array with confinement effects

A monodisperse 1D colloidal array is prepared from monomer directly combining precipitation polymerization and confinement effects.     

On a nonlocal problem modelling Ohmic heating in planar domains

In this paper, we consider the nonlocal problem of the form ut-Δu = (λe-u)/(∫Ωe-udx)2,x ∈Ω, t0 and the associated nonlocal stationary problem -Δv = (λe-v)/(∫Ωe-vdx)2, x ∈Ω,where λ is a positive parameter. For Ω to be an annulus, we prove that the nonlocal stationary problemhas a unique solution if and only if λ 2| Ω| 2 , and for λ = 2|Ω|2, the solution of the nonlocal parabolic problem grows up globally to infinity as t →∞.     

多级轴流压气机稳定性数值研究

本文以某压气机前五级为研究对象,利用计算流体力学方法研究了可转静叶对提高压气机部分转速下喘振裕度的效果,研究表明,可转静叶能够明显地提高压气机部分转速下的喘振裕度。通过分析影响压气机不稳定性的因素,给出了一个扩压参数来衡量压气机稳定性和承载能力,从而指导选取最优可转静叶安装角,使压气机喘振裕度达到最大,并在该参数的指导下,得出了可转静叶的一组最优安装角。     

White matter abnormalities in children and adolescents with temporal lobe epilepsy

Background and Purpose

The widespread propagation of synchronized neuronal firing in seizure disorders may affect cortical and subcortical brain regions. Diffusion tensor imaging (DTI) can noninvasively quantify white matter integrity. The purpose of this study was to investigate the abnormal changes of white matter in children and adolescents with focal temporal lobe epilepsy (TLE) using DTI.

Materials and Methods

Eight patients with clinically diagnosed TLE and eight age- and sex-matched healthy controls were studied. DTI images were obtained with a 3-T magnetic resonance imaging scanner. The epileptic foci were localized with magnetoencephalography. Fractional anisotropy (FA), mean diffusivity (MD), parallel (λ_||) and perpendicular (λ_⊥) diffusivities in the genu of the corpus callosum, splenium of the corpus callosum (SCC), external capsule (EC), anterior limbs of the internal capsule (AIC), and the posterior limbs of the internal capsule (PIC) were calculated. The DTI parameters between patients and controls were statistically compared. Correlations of these DTI parameters of each selected structure with age of seizure onset and duration of epilepsy were analysed.

Results

In comparison to controls, both patients' seizure ipsilateral and contralateral had significantly lower FA in the AIC; PIC and SCC and higher MD, λ_|| and λ_⊥ in the EC, AIC, PIC and SCC. The MD, λ_|| and λ_⊥ were significantly correlated with age of seizure onset in the EC and PIC. λ_|| was significantly correlated with the duration of epilepsy in the EC and PIC.

Conclusion

The results of the present study indicate that children and adolescents with TLE had significant abnormalities in the white matter in the hemisphere with seizure foci. Furthermore, these abnormalities may extend to the other brain hemisphere. The age of seizure onset and duration of epilepsy may be important factors in determining the extent of influence of children and adolescents TLE on white matter.