Highly photoluminescent multilayer QD-glass films prepared by LbL self-assembly

A novel and facile preparation method for layer-by-layer (LbL) self-assembled films incorporating quantum dots (QDs) and having intense photoluminescence (PL) from blue to red is presented. Functional sol-gel-derived glass layers prepared by the hydrolysis of 3-aminopropyltrimethoxysilane (APS) or 3-mercaptopropyltrimethoxysilane (MPS) have been used as a linkage between QD layers. Absorption, PL spectroscopy, transmission electron microscopy, and atomic force microscopy were employed for characterization, which revealed that the QDs in the prepared films had a nearly close-packed coverage and were not aggregated. The PL efficiencies of the QDs (CdTe or ZnSe, both are thioglycolic acid-stabilized) dispersed in the films were roughly half that of the initial colloidal solutions but reached 24% before a refractive index correction. The thickness of the red-emitting film with 10 CdTe QD layers was approximately 50 nm. The concentration of QDs in the film derived from the first absorption peak was approximately 0.01 M. Because the PL starts to show a red shift, the obtained concentration is practically the ultimate one in the glass matrix. The mercapto, amino, and carboxyl groups play important roles in LbL self-assembling processes.     

Fundamental studies on the intermediate layer of a bipolar membrane: Part III. Effect of starburst dendrimer PAMAM on water dissociation at the interface of a bipolar membrane

Starburst dendrimer polyamidoamine (PAMAM) with ellipsoidal or spheroidal shape is structure-regular and has much more amino groups than conventional polymers. This paper investigates the possibility of these amino groups on water dissociation in a bipolar membrane interface. To do this, a bipolar membrane is prepared by casting the solution of sulfonated poly(phenylene oxide) (SPPO) in dimethyl formamide (DMF) on a commercial anion exchange membrane that is immersed in PAMAM aqueous solution in advance. The existence of PAMAM adsorbed on the membrane is proved by X-ray photoelectron spectroscopy (XPS), and the adsorption amount is evaluated by weighting method. The junction thickness of the prepared bipolar membrane is determined by electrochemical impedance spectroscopy (EIS), and the performance is evaluated by current–voltage curves. The experiments show that both the generation and concentration of PAMAM would strongly affect the characteristics of the bipolar membranes. There exists a transitional concentration for various generations PAMAMs to catalyze effectively the water dissociation, and above or below the transitional concentration the performance of bipolar membranes is decreasing. The higher the generation, the lower the concentration. Moreover, at a fixed solution concentration, there is not the simple relation of monotone decreasing or increasing between the performance of bipolar membranes and the generations of PAMAMs. All these can be explained according to the characteristics of PAMAMs combined with available water dissociation theory.     

Analysis of effective molecular diffusion rates for verteporfin in subcutaneous versus orthotopic Dunning prostate tumors

Photosensitizer biodistribution change inside tissue is one of the dominant factors in photodynamic therapy efficacy. In this study, the pharmacokinetics of a benzoporphyrin derivative (BPD), delivered in verteporfin for injection formulation, have been quantified in the rat Dunning prostate tumor MAT-LyLu model, using both subcutaneous and orthotopic sites. Blood plasma sampling indicated that BPD had a bi-exponential metabolic lifetime in vivo, with the two lifetimes being 9.6 min and 8.3 h. The spatial distributions in the tumor were quantified as a function of distance from the perfused blood vessels, using fluorescence histologic images of the tumor. A fluorescent vascular marker was used to obtain locations and shapes of perfused capillaries at a wavelength of emission different from that of BPD and to allow colocalized images to be acquired of vessel and BPD locations. Using the BPD fluorescence images obtained 15 min after intravenous administration, a forward finite-element solution to the diffusion equation was used to predict the drug distribution by matching the fluorescence intensity images observed microscopically. An inverse solver was used to minimize the root mean square error between the image of simulated diffusion and the experimental image, resulting in estimation of the diffusion coefficient of BPD in the tumor models. Effective diffusion coefficients were 0.88 and 1.59 microm2/s for the subcutaneous and orthotopically grown tumors, respectively, indicating that orthotopic tumors have significantly higher vascular extravasation rates as compared with subcutaneous tumors. This analysis supports the hypothesis that leakage rates of the photosensitizer vary considerably. Thus, although varying the time between injection and optical irradiation may be used to vary the targeting between vascular and less vascular areas, the precise time of treatment will depend on the nature of the permeability of the vasculature in the tissue being treated.     

Studies on the Complexes of N,N′-Bis[o-(diphenylphosphino)benzylidene]ethylenediamine with Transition Metal Ions

The thermodynamic parameters for the interaction of Cu²⁺, Ni²⁺, Co²⁺, Cd²⁺, andAg⁺ with the new title ligand have been determined by titration calorimetry in 50% THF–methanol (V/V) at 25 °C.Ag⁺ exhibited remarkably higher complexation selectivity.Ag⁺ and several transition metal ions have been transportedusing this ligand as carrier in a bulk liquid membrane. CompetitiveAg⁺–M²⁺ transport studies have also beencarried out for the same system. In this membrane transport study, high transport of Ag⁺ was observed in both single and competitiveAg⁺–M²⁺ transport studies. The complexformation of N,N-bis[o-(diphenylphosphino)benzylidene]ethylenediamine (P₂N₂) with silver,[Ag(P₂N₂)] (NO₃), (1) is reported. Complex 1 has been characterized by X-ray crystallography. 1 ismonoclinic, space group P2_1/n (No. 14), with cell dimensionsa = 13.398(4) , b=12.577(5) , c = 21.521(4) , =100.14(2) , V = 3570(2) ³ and Z = 4.     

Chemical fixation of CO2 with highly efficient ZnCl2/[BMIm]Br catalyst system

The chemical fixation of CO₂ with mono-substituted terminal epoxides or cyclohexene oxide to form cyclic carbonates under the ZnCl₂/[BMIm]Br catalyst system without using additional organic solvents was achieved in excellent selectivity (>98%) and TOF (5410 h⁻¹) and the catalyst could be used six times almost without losing its catalytic activity and selectivity. Besides, the pure cis-cyclic carbonate of cyclohexene oxide was obtained in this catalyst system.     

Bis­(ethyl­enedi­amine)copper(II) bis(O,O′‐diethyl di­thio­phosphate)

In the structure of the title compound, [Cu^II­(en)₂][(EtO)₂P(S)S]₂ (en is ethyl­ene­di­amine) or [Cu(C₂H₈N₂)₂](C₄H₁₀O₂PS₂)₂, the Cu atom lies on a center of inversion and is coordinated in a slightly distorted square coordination geometry by four N atoms from two ethyl­enedi­amine mol­ecules. The diethyl di­thio­phosphate moieties, (EtO)₂P(S)S^?, act as counter‐anions.     

双核银络合物[Ag_2(dppm)_2(Py)_2(μ-Cl)]ClO_4的合成与结构

二-(二苯基膦)甲烷(dppm)是一种易与金属形成多核络合物的有机膦配体。我们用dppm作为配体合成了一系列银的多核络合物,并对其结构进行了研究。本文报导了其中一个双核化合物[Ag_2(dppm)_2(Py)_2(μ-Cl)]ClO_4的合成及晶体结构、分子结构的测定。     

尺寸排除色谱扩展因子的保留体积依赖性

尺寸排除色谱扩展函数的方差即尺寸排除色谱柱中单分散高分子峰的扩展因子,以窄分布聚苯乙烯标样用分子量分离和扩展效应同时标准的方法作了测量。简单的理论分析导出了一个方程以表示扩展因子的保留体积依赖性,其中包括四个具有明确物理意义并可实验测量的参数。该方程与实验数据符合得相当好,并解释了扩展因子极值出现的条件。     

石墨炉原子吸收光谱无标样分析法的研究：Ⅰ.消除基体干扰

实现石墨炉原子吸收光谱绝对分析必须消除基体干扰，本研究采用有机基体改进剂，管壁原子化、热解涂层石墨管，峰面积积分吸收信号，Ｄ２灯或Ｚｅｅｍａｎ效应扣除背景，有效地控制和消除了海水基体对Ａｓ，Ｃｄ，Ｃｏ，Ｃｒ，Ｃｕ，Ｍｎ，Ｎｉ，Ｐｂ和Ｖ等元素的干扰，实现了无干扰测定。     

应用扩展的重叠分辨率法优化液相色谱条件分离二茂铁类化合物

本文对优化液相色谱分离条件的重叠分辨率法进行了改进与扩展：首先利用全范围的二元线性梯度淋洗进行溶剂强度的优化，再通过重叠分辨率法进行了溶剂选择性的优化，并且建立了计算机系统，使此方法程序化。利用此方法建立了分离Ｎ－二茂铁甲酰基－Ｎ＇－芳基硫脲类衍生物的最佳流动相体系。