染料木素磺化衍生物的合成及其与人血清白蛋白作用的研究

以染料木素为原料,利用Mannich反应,设计合成了其与胺(正丁胺、异丙胺、二乙胺)的Mannich碱衍生物,再进一步磺化,从而制得3个磺化衍生物(GSD),对其结构用ESI-MS、1H NMR、13C NMR表征确认.应用荧光光谱、紫外-可见吸收光谱方法研究了它们与人血清白蛋白(HSA)的相互作用机制.结果表明,GSD与HSA结合并引起其内源荧光的猝灭,该猝灭过程以静态猝灭为主.根据热力学参数确定了该结合主要是通过氢键和范德华力,是一个自发的放热过程.同时,根据紫外-可见吸收光谱及同步荧光光谱探讨结合后HSA的构象改变.     

一种改进的DNN-HMM的语音识别方法*

针对深度神经网络与隐马尔可夫模型(DNN-HMM)结合的声学模型在语音识别过程中建模能力有限等问题,提出了一种改进的DNN-HMM模型语音识别算法。首先根据深度置信网络(DBN)结合深度玻尔兹曼机(DBM),建立深度神经网络声学模型,然后提取梅尔频率倒谱系数(MFCC)和对数域的Mel滤波器组系数(Fbank)作为声学特征参数,通过TIMIT语音数据集进行实验。实验结果表明:结合了DBM的DNN-HMM模型相比DNN-HMM模型更具优势,其中,使用MFCC声学特征在词错误率与句错误率方面分别下降了1.26%和0.20%。此外,使用默认滤波器组的Fbank特征在词错误率与句错误率方面分别下降了0.48%和0.82%,并且适量增加滤波器组可以降低错误率。总之,研究取得句错误率与词错误率分别降低到21.06%和3.12%的好成绩。     

Exact controllability for 1‐D quasilinear wave equations with internal controls

For 1‐D quasilinear wave equations with different types of boundary conditions, based on the theory of the local exact boundary controllability, using an extension method, the author establishes the exact controllability in a shorter time by means of internal controls acting on suitable domains. In particular, the exact controllability can be realized only by internal controls, and the control time can be arbitrarily small. Copyright © 2016 John Wiley & Sons, Ltd.     

Fabrication of homogeneous and enhanced soybean protein isolate-based composite films via incorporating TEMPO oxidized nanofibrillated cellulose stablized nano-ZnO hybrid

Soybean protein isolate (SPI) is well-suited to the preparation of composite films due to its abundance, renewability, biodegradability, and favorable film-forming capacity. In this study, different SPI-based composite films were prepared by incorporating nano-ZnO and 2,2,6,6-Tetramethylpiperidine 1-oxyl (TEMPO) oxidized nanofibrillated cellulose (TNFC) separately or together. Nano-ZnO was introduced to endow the films with multifunction capability, while TNFC was introduced to stabilize the nanoparticles. Both the macro optical characterization and micro scanning electron microscope with energy dispersive X-ray (SEM–EDX) analysis indicated that TNFC could significantly decrease nano-ZnO aggregation and improve its dispersibility in the SPI matrix due to the mechanical restriction and physical adsorption effect of TNFC to the nano-ZnO. In addition to the improved dispersibility, incorporating nano-ZnO and TNFC benefitted the mechanical properties and thermo stability of the SPI-based composite films. The tensile strength and Young’s modulus increased by 73 and 57%, respectively, and the maximum degradation temperature increased by 10 °C, compared to that of the unmodified SPI film. These results can be attributed to the hydrogen bonds formed among SPI components, TNFC, and nano-ZnO, which were further examined by attenuated total reflectance-fourier transform infrared spectroscopy and X-ray diffraction analysis. After the incorporation of nano-ZnO, the SPI-based composite films also possessed excellent UV-shielding capacity and superior antimicrobial ability. To this effect, this work provides a valuable reference for nanoparticles dispersion and application in regards to polymer enhancement and multi-functionalization.     

Preparation of single-walled carbon nanotube fiber coating for solid-phase microextraction of organochlorine pesticides in lake water and wastewater

The feasibility of single-walled carbon nanotubes (SWCNTs) as adsorbents for solid-phase microextraction was investigated by using organochlorine pesticides (OCPs) as model compounds. SWCNTs were attached onto a stainless steel wire through organic binder. Potential factors affecting the extraction efficiency were optimized, including extraction time, extraction temperature, desorption time, desorption temperature, and salinity. The developed method has a linear range of 2-800 ng/L for most analytes, with coefficients of correlation ranging from 0.9911 to 0.9996, LODs ranged from 0.19 to 3.77 ng/L (S/N = 3), and RSDs in the range of 3.5-13.9% (n = 5). Compared with the commercial PDMS fiber, the SWCNT fiber has better thermal stability (over 350 degrees C) and longer life span (over 150 times). The developed method was applied to determine trace OCPs in lake water and wastewater samples with external standard calibration. Results showed that OCP contamination was very low in these samples, and HCHs were detected in almost all water samples while DDT concentrations were almost under detection limits in these samples. Recoveries obtained at 20 ng/L spiking level were in the range of 88.4-111% for OCPs in lake water. For wastewater samples, however, the recoveries were satisfactory for HCHs (63.6-97.1%) but relatively low for DDTs (44.7-116%) due to the high content of organic matter in wastewater.     

一种高透明、可拉伸导电水凝胶的制备及其在电容传感器中的应用

导电水凝胶由于具备良好的电学特性、可调节的机械性能、易于加工性和生物相容性等,是制备柔性电子设备的理想基材。本文使用马来酸与丙烯酰胺作为共聚单体,氯化锂作为导电离子,N,N'-二甲基双丙烯酰胺作为交联剂,使用光引发剂,采用原位光聚合的方式制备了一种导电水凝胶。制得的水凝胶可见光透过率高达93%,最大拉伸形变~380%,导电率最大为12 S/m。鉴于其优异的综合性能,实验中使用导电水凝胶制备了电容传感器并应用于人体活动监测。结果表明,制备的导电水凝胶电容传感器对不同程度的手指弯曲形变和不同力度的手指触碰均表现出灵敏的响应行为,为未来可穿戴柔性电子产品的发展起到了一定的推动作用。     

Selection of bovine catalase aptamers using non-SELEX

In this research, we used the non-SELEX method to successfully select an aptamer that binds to the protein target (bovine catalase) with a K(D) value in the low micro molar range. The time window was determined for the target and aptamer library by optimizing the buffer conditions using 3 × Tris-glycine-potassium phosphate (TGK) buffer as the run buffer and 1× TGK as the selection buffer to give the biggest complex peak. Fractions were collected by multistep nonequilibrium capillary electrophoresis of equilibrium mixtures (NECEEM)-based partitioning for three rounds of selection. The fractions from each round were enriched using PCR and the progress of selection was monitored using bulk affinity analysis. Fraction 2 was determined to have the optimal bulk affinity (0.75 μM) and this enriched library was cloned and sequenced giving four aptamer sequences. These sequences were verified using affinity capillary electrophoresis (CAT 1 0.237 μM) and fluorescence intensity measurements (CAT 1 0.430 μM). The specificity of the aptamer was also determined by fluorescence intensity measurements. The results showed that the aptamer with the highest binding affinity showed at least a 100-fold decrease in affinity toward four other proteins (i.e. lysozyme, trypsinogen, chymotrypsinogen A, and myoglobin) tested and this confirmed that the aptamer exhibited a distinct specificity toward bovine catalase. This aptamer will be useful in biosensing, Western blot, and biomarker identification.     

Green Electrospun Silk Fibroin Nanofibers Loaded with Cationic Ethosomes for Transdermal Drug Delivery

Transdermal drug delivery system(TDDS) facilitates the controlled release of active ingredients penetrating through the skin, avoiding the liver first pass effect. Electrospinning is a simple process to fabricate ultrafine fibers with a higher specific surface area, making them excellent candidates for drug delivery. In current work, a novel silk fibroin(SF) nanofiber loaded with cationic ethosomes(CEs) was prepared via green electrospinning. The data of Fourier transform infrared spectroscopy(FTIR) and laser scanning confocal microscopy(LSCM) confirmed the existence of CEs in the SF nanofibers. The morphology of the nanofibers was not significantly affected by the incorporation of CEs as shown by scanning electron microscopy(SEM) images. The CEs-loaded SF nanofibrous patch (CEs-SFnP) showed good cytocompatibility as proved by both cell counting Kit-8(CCK-8) assay and SEM. Using doxorubicin hydrochloride(Dox) as a model drug, the transdermal performance of CEs-SFnP was evaluated through Franz diffusion cell against mouse skin. The results indicated that CEs-SFnP can effectively deliver drug into the skin, with a much higher permeation rate than the normal nanofibers without CEs. The as-spun CEs-SFnP in this study could find promising applications in TDDS.     

First halogen anion-bridged (MMX)(n)-type one-dimensional coordination polymer built upon d(10)-d(10) dimers

The complex [Ag(2)(PhPPy(2))(2)(NCCH(3))(2)](ClO(4))(2) [PhPPy(2) = bis(2-pyridyl)phenylphosphine] reacts with NH(4)Cl to form an insoluble one-dimensional polymer of the type (MMX)(n), {[Ag(2)(PhPPy(2))(2)Cl](ClO(4))}(n). The binuclear unit, Ag(2)(PhPPy(2))(2)(2+), exhibits two PhPPy(2) tridentate ligands bridging the two Ag atoms in a head-to-tail fashion with C(2h) symmetry, and the Ag···Ag distance [3.0942(11) ?, X-ray] suggests argentophilic interactions. Each Ag center adopts a distorted trigonal-bipyramidal geometry, coordinated by one P atom and two pyridyl arms at the equatorial positions and interacting with one Cl ion and one Ag ion at the axial positions. The short Ag-Cl bond length [2.5791(7) ?] indicates the presence of some covalent character. The solid-state absorption bands spread all the way to 600 nm have been interpreted by means of density functional theory (DFT) and time-dependent DFT (B3LYP), and the lowest-energy excited states are assigned to metal/halide-to-pyridyl charge transfer, consistent with the d(10) electronic configuration of Ag. The calculated oscillator strengths are low because of the poor molecular orbital overlaps in the charge-transfer components. The novel material exhibits a luminescence band centered at about ～520 nm.