A carbohydrate-linked hypericinic photosensitizing agent

With respect to an enhanced solubility under physiological conditions, a carbohydrate-containing hypericin-based second-generation photosensitizer was prepared. Its photochemical properties were tested by means of the light-sensitized destruction of bilirubin IXα to be even better than those of the parent compound hypericin. Investigations on binding-interactions with DNA showed promising results as well.     

Polymer coated sensor array based on quartz crystal microbalance for chemical agent analysis

Quartz crystal microbalance (QCM) gas sensors based on polymeric material were fabricated and their gas response characteristics were examined for four simulant gases of chemical agents, which were dimethyl methyl phosphonate (DMMP), N,N-dimethylacetamide (DMA), 1,5-dichloropentane (DCP) and dichloroethane (DCE). For the selection of appropriate coating materials, both principal component analysis (PCA) and hierarchical cluster methods were applied to a data set collected from 15 QCM sensors for 12 analytes. Four appropriate coating materials were selected after optimizing the correlation between the 15 coating materials and the first four principal component (PC) factors. The four chosen polymers were used as sensitive component for a sensor array, and then PCA is adapted to classify four simulant gases. The results show that the QCM sensor array has high sensitivity and selectivity to four chemical agents.     

Effect of nucleating agent supported on zeolite via the impregnation on the crystallization ability of isotactic polypropylene and its mechanism

Addition of an α‐nucleating agent is the simple and effective method to increase nucleation efficiency of isotactic polypropylene (iPP). However, severe agglomeration and poor dispersibility of sodium 2,2′‐methylene‐bis(4,6‐di‐tertbutylphenyl) phosphate (NA11) decrease the nucleation efficiency in the iPP, and much more nucleating agent is needed to maintain the nucleating property. As a result, it becomes the key how to decrease the size of NA11 and increase the nucleating property. In this paper, zeolite 4A (Z4A) was firstly supported by NA11 through solution impregnation, and NA11 was dispersed by Z4A depending on the dispersion of zeolite as carrier for the second component. Then, the dispersed NA11 system (NA11‐Z4A) exhibited a superior nucleation behavior during the crystallization of the iPP matrix when it was used with iPP together. The isothermal and nonisothermal crystallization kinetics indicated that the NA11‐Z4A/iPP system had the best crystallization effect. Polarized optical microscopy (POM) and scanning electron microscopy (SEM) analyses showed that the size of NA11 decreased obviously when it was adsorbed on the surface of Z4A, which leads a better dispersibility of the nucleating agent and thus an accelerated nucleation process in the iPP matrix. In the end, the mechanism for the excellent dispersibility of NA11‐Z4A, which was based on hydrogen bonding between NA11 and Z4A, was confirmed by Fourier‐transform infrared spectroscopy (FTIR). Based on the research work, the solution impregnation strategy can potentially be applied to other systems to inhibit the agglomeration and improve the dispersibility of additives in iPP.     

Hydrophobic modification of SiO2 surface by aminosilane derivatives

New aminosilanes with hydrolysable Si-N bond(s) were prepared by the amination of chlorosilanes and used as hydrophobic modifiers of SiO₂ surface. The aminosilanes are rather stable towards hydrolysis in air compared to their chlorosilane analogs. The modified SiO₂ was applied as a gate insulator of an organic thin-film transistor with a vapor-deposited film of pentacene as the active material. The transistor with the aminosilane-modified SiO₂ showed two- to threefold higher hole mobility than the device with bare SiO₂.     

Regioselective bromination of arenes mediated by triphosgene-oxidized bromide

This article first time describes triphosgene (BTC) as an oxidant while the non-toxic and easy-to-handle potassium bromide (KBr) as the source of bromine to the bromination reaction of aromatic substrates. The novel brominating protocol gives excellent para-regioselectivity of the alkoxyl/hydroxyl arenes and high yield, offering good potential of commercial scale applications. The mechanism of “Triphosgene oxidize bromide” was proposed.     

多媒体远程教育网中基于Mobile Agent的网络管理

介绍了ＭｂＭＡ（Ｍａｎａｇｅｍ ｅｎｔ ｂｙ Ｍｏｂｉｌｅ Ａｇｅｎｔ）的系统组成及ＭｂＭＡ 中Ａｇｅｎｔ的分类和各自的功能,提出了基于Ｍｏｂｉｌｅ Ａｇｅｎｔ的多媒体远程教育网的网管体系,由于引入了能够集成ＳＮＭＰ设备的ＭｂＭＡ 代理服务器,增强了该体系的实用性．     

Echinops bannaticus plant and Zinnia grandiflora extract as char biosource and reducing agent for the biosynthesis of Ag on magnetic char-polymer: An efficient catalyst for water treatment

In attempt to expand the use of natural compounds for waste treatment, a novel catalyst with the utility for dye reductive degradation is reported. In the catalyst synthesis procedure, the plant Echinops bannaticus was applied as a biosource and hydrothermally treated to furnish a hydrochar that served as a support. The latter was magnetized, vinyl functionalized, and then polymerized with copolymer of 2-hydroxyethyl methacrylate and methacrylate polyhedral oligomeric silsesquioxane. Subsequently, Ag nanoparticles were stabilized on the resultant composite with the aid of Zinnia grandiflora extract as a natural reducing agent. The resulting catalyst displayed high catalytic activity for the reduction of methylene orange and rhodamine B dyes in aqueous media at room temperature. The effects of the reaction variables, including the reaction time and temperature, and the catalyst loading, were examined and the kinetic and thermodynamic terms for both reactions were evaluated. E_a, ΔH^#, and ΔS^# values for the reduction of methyl orange were estimated as 50.0 kJ/mol, 51.50 kJ/mol, and −102.42 J mol⁻¹ K⁻¹, respectively. These values for rhodamine B were measured as 28.0 kJ/mol, 25.5 kJ/mol, and −187.56 J mol⁻¹ K⁻¹, respectively. The recyclability test also affirmed that the catalyst was recyclable for several runs with insignificant Ag leaching and decrement of its activity.     

Determination of cyclosporin A in blood and plasma by column switching-HPLC after rapid sample preparation

A method for the determination of cyclosporin A in human whole blood and plasma is described which uses liquid chromatography with step gradient elution and a column switching technique. The chromatographic conditions chosen allow simple and rapid sample preparation, so that a result can be obtained within one hour. Blood and plasma are deproteinized with diluted methanol and an aliquot of the clear supernatant is directly injected. The detection limit for cyclosporin A is about 20 ng/ml starting from a 0.5 ml sample. The method is sensitive enough for monitoring the drug in the therapeutic range.     

Poly(vinylidene fluoride) (PVDF)/potassium sodium niobate (KNN)–based nanofibrous web: A unique nanogenerator for renewable energy harvesting and investigating the role of KNN nanostructures

In the recent era, finding renewable energy sources that are environmentally benign the main focus of scientific community around the globe. There is a plenty of renewable energy sources that are currently being researched such as solar power, thermal energy, wind energy, salinity gradients, and kinetic energy. Polymer‐ceramic–based nanocomposite piezoelectric material is known for quite some time for energy harvesting, but the real challenge lies as it requires very high loading of the ceramic part to obtain the required property and thus almost makes the system nonflexible. Developed material needs to be poled later on to use it as an electric energy generator from ambient mechanical movement. This current study is the first time attempt to produce a simple yet unique lightweight energy harvester using polyvinylidene fluoride (PVDF)/potassium sodium niobate (KNN) nanostructures–based nanocomposite flexible fibrous web where the material is in situ poled during its production using an electrospinning setup. At the beginning, various parameters were identified to synthesize and modulate KNN as nanostructural materials having higher aspect ratio, which is intended to provide a unique connection between KNN once these are embedded within the fibrous matrix. The incorporated KNN nanostructure having higher aspect ratio was also found to act as a beta nucleating agent in PVDF matrix and enhances the β‐phase crystal into the resultant fibrous web, which in turn increases the piezoelectric energy‐harvesting capacity manifold as compared with bare PVDF fibrous web. The in situ alignment of the nanostructured KNN (with a minimum loading, 5% only) into the fibrous nanocomposite is another achievement to obtain higher output. X‐ray diffraction and Fourier transform infrared analysis confirmed the mixture of α‐ and β‐crystalline phase of pure PVDF, which gets converted into β phase once KNN nanostructures are incorporated inside the nanofibrous web. An output voltage of 1.9 V was obtained from PVDF/KNN nanocomposite–based web, which is significantly higher (38 times) than generated voltage (50 mV) from the pure PVDF nanoweb without any subsequent poling operation.