Facile synthesis of ABCDE‐type H‐shaped quintopolymers by combination of ATRP,ROP, and click chemistry and their potential applications as drug carriers

A facile approach to synthesis of ABCDE‐type H‐shaped quintopolymer comprising polystyrene (PSt, C) main chain and poly(ethylene glycol) (PEG, A), poly(ε‐caprolactone) (PCL, B), poly(L ‐lactide) (PLLA, D), and poly(acrylic acid) (PAA, E) side chains was described, and physicochemical properties and potential applications as drug carriers of copolymers obtained were investigated. Azide‐alkyne cycloaddition reaction and hydrolysis were used to synthesize well‐defined H‐shaped quintopolymer. Cytotoxicity studies revealed H‐shaped copolymer aggregates were nontoxic and biocompatible, and drug loading and release properties were affected by macromolecular architecture, chemical composition, and pH value. The release rate of doxorubicin from copolymer aggregates at pH 7.4 was decreased in the order PAA‐b‐PLLA > H‐shaped copolymer > PEG‐PCL‐PSt star, and the release kinetics at lower pH was faster. The H‐shaped copolymer aggregates have a potential as controlled delivery vehicles due to their excellent storage stability, satisfactory drug loading capacity, and pH‐sensitive release rate of doxorubicin. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

Combustion synthesis and luminescence properties of NaY1−xEux(WO4)2 phosphors

The red phosphors NaY_1−xEu_x(WO₄)₂ with different concentrations of Eu³⁺ were synthesized via the combustion synthesis method. As a comparison, NaEu(WO₄)₂ was prepared by the solid-state reaction method. The phase composition and optical properties of as-synthesized samples were studied by X-ray powder diffraction and photoluminescence spectra. The results show that the red light emission intensity of the combustion synthesized samples under 394 nm excitation increases with increase in Eu³⁺ concentrations and calcination temperatures. Without Y ions doping, the emission spectra intensity of the NaEu(WO₄)₂ phosphor prepared by the combustion method fired at 900 °C is higher than that prepared by the solid-state reaction at 1100 °C. NaEu(WO₄)₂ phosphor synthesized by the combustion method at 1100 °C exhibits the strongest red emission under 394 nm excitation and appropriate CIE chromaticity coordinates (x=0.64, y=0.33) close to the NTSC standard value. Thus, its excellent luminescence properties make it a promising phosphor for near UV InGaN chip-based red-emitting LED application.     

光学微扫描显微热成像扫描零点定标方法研究

为改善已研制光学微扫描显微热成像系统的空间分辩力,微扫描零点需要确定.基于几何原理,研究提出了一种利用数字图像处理技术进行零点定标的方法.给出了微扫描零点的定义、详细分析了零点定标原理及方法,完成了实际显微热成像系统的微扫描零点定标.针对红外热图像,模拟零点定标前后的实际系统,采用不同重构方法进行了仿真研究,给出了评价参数;利用零点定标后的光学微扫描显微热成像系统采集低分辨力显微热图像序列进行过采样重构研究,仿真和实验结果表明了该方法的有效性,从而得到了高分辨力光学微扫描显微热成像系统,可应用于需要显微热分析的场合.     

Multi-residue detection of pesticides using a sensitive immunochip assay based on nanogold enhancement

This paper describes the development of a new multiplex immunoassay for simultaneous detection of seven pesticides (triazophos, methyl-parathion, fenpropathrin, carbofuran, thiacloprid, chlorothalonil, and carbendazim). Sixteen pairs of pesticide antibodies and antigens were screened for reactivity and cross-reaction. A microarray chip consisting of seven antigens immobilized on a nitrocellulose membrane was then constructed. Nanogold was employed for labeling and signal amplification to obtain a sensitive colorimetric immunoassay. The direct and indirect detection formats were further compared using primary antibody-gold and secondary antibody-gold conjugates as tracers. An integrated 7-plex immunochip assay based on the indirect model was established and optimized. The detection limits for the pesticides were 0.02–6.45 ng mL⁻¹, which meets detection requirements for pesticide residues. Naked-eye assessment showed the visual detection limits of the assay ranged from 1 to 100 ng mL⁻¹. Spiked recovery results demonstrated that the immunochip assay had potential for multi-analysis of pesticide residues in vegetables and fruits. The proposed microarray methodology is a flexible and versatile tool, which can be applied to other competitive multiplex immunoassays for small molecular compounds.     

Achieving over 16% efficiency for single-junction organic solar cells

To achieve high photovoltaic performance of bulk hetero-junction organic solar cells(OSCs), a range of critical factors including absorption profiles, energy level alignment, charge carrier mobility and miscibility of donor and acceptor materials should be carefully considered. For electron-donating materials, the deep highest occupied molecular orbital(HOMO) energy level that is beneficial for high open-circuit voltage is much appreciated. However, a new issue in charge transfer emerges when matching such a donor with an acceptor that has a shallower HOMO energy level. More to this point, the chemical strategies used to enhance the absorption coefficient of acceptors may lead to increased molecular crystallinity, and thus result in less controllable phase-separation of photoactive layer. Therefore, to realize balanced photovoltaic parameters, the donor-acceptor combinations should simultaneously address the absorption spectra, energy levels, and film morphologies. Here, we selected two non-fullerene acceptors, namely BTPT-4F and BTPTT-4F, to match with a wide-bandgap polymer donor P2F-EHp consisting of an imidefunctionalized benzotriazole moiety, as these materials presented complementary absorption and well-matched energy levels. By delicately optimizing the blend film morphology, we demonstrated an unprecedented power conversion efficiency of over 16% for the device based on P2F-EHp:BTPTT-4F, suggesting the great promise of materials matching toward high-performance OSCs.     

Facile synthesis and versatile topological transformation of mono-cleavable symmetric starlike terpolymers

A straightforward strategy involving a RAFT process and ring-opening polymerization was used to construct symmetric reduction-responsive amphiphilic A(2m)B(2n)C(2) (m≈n≈ 3) starlike terpolymers with precise microstructure, which could be efficiently converted into thiol-functionalized telechelic stars, degraded A(m)B(n)C miktoarm stars and comblike-linear multiblock copolymers via postmodification.     

显微热成像系统自适应位置标定方法

利用光学微扫描技术,可在不改变探测器结构的情况下,提高显微热成像系统空间分辨率。但为了获得高质量过采样重构图像,微扫描位置需要标定。基于零点定标,提出一种各点自适应定标的微扫描位置标定方法。模拟实际系统在定标前后的欠采样图像,采用不同重构方法进行仿真对比验证;完成了实际采集的欠采样显微热图像序列的重构对比实验。实验结果表明该方法明显改善了显微热成像系统的过采样重构图像质量,提高了系统空间分辨率。此方法还可以应用在其他光电成像系统中。     

基于不可控微扫描的高分辨力图像重构方法

针对存在不可控微位移的序列低分辨力图像,提出了一种基于2×2不可控微扫描的高分辨力图像重构方法,采用投影法估算出低分辨力图像LR的微位移量,采用基于泰勒级数展开的重构算法由4帧图像重构高分辨力图像.模拟表明:该算法能精确地估计序列图像的帧间位移量并取得较好的重构效果,且算法简单有效可行,处理量小,有利于实现快速处理,在一定程度可满足同步轨道卫星、公安监视等领域对高分辨力成像处理的需求.     

一种基于改进频域图像配准技术的超分辨力图像处理方法

为提高光电成像系统的空间分辨力,提出了一种基于改进的频率域图像配准技术的超分辨力图像处理方法。首先利用改进的频域图像配准方法估算出低分辨力图像之间的微位移量,然后采用Papoulis-Gerchberg超分辨力处理方法完成图像复原。利用不同重构方法进行了仿真及实验研究,给出了评价参数。模拟和实际显微热图像的处理结果表明:该算法可使图像质量得到改善,分辨的细节更多,可有效地提高光电成像系统的空间分辨力;处理算法简单,计算量小,可实现快速处理。该算法还可应用于其他不可控光学微扫描成像系统中,具有广泛的应用前景。