可交联聚甲基丙烯酸甲酯的合成、表征及在阵列式波导光栅中的应用

合成了含环氧基团的可交联的甲基丙烯酸甲酯和甲基丙烯酸环氧丙酯的共聚物[Poly(MMA-co-GMA)],通过FTIR,NMR,GPC,DSC和AFM等技术对其进行了表征. 结果表明,所合成的聚合物材料具有较好的成膜性; 通过热固化使引入的环氧基团开环交联,该聚合物的玻璃化转变温度(Tg)比固化前提高了24 K,同时有效地降低了聚合物的双折射率. 用Poly(MMA-co-GMA)作为包层材料,双酚A型环氧化合物作为高折射率材料, 将其引入到包层材料中形成芯层材料的折射率在波长1.55 μm处可调,其范围是1.483~1.588. 采用旋涂、 铝掩膜和氧反应离子刻蚀的方法(RIE)制得了阵列式光波导. 测试结果表明,制作的波导在1.55 μm处实现了光的单模传输,光损小于3.0 dB/cm.      

液晶CPBOB吸附的STM研究

利用STM对吸附在导电基底上的液晶进行研究，能提供近原子分辨的液晶分子图象，这一创新不仅拓宽了STM的研究领域，也使STM成为研究液晶吸附的重要手段之一．根据液晶相变特征不同，样品的制备方法大致分四种情况：直接法，加热法，气相沉积法和溶剂法．无论采用以上哪种方法，     

五磷酸铽荧光光谱偏振特性的研究

本文报告了在77 K下TbP_5O_(14)中Tb~(3+)离子的~5D_4-~7F_J, 跃迁荧光光谱的偏振特性。根据退偏度的规律认定了~5D_4和~7F_J的大部分Stark能级的标号。     

Prototype of immunochromatographic assay strips using colloidal CdTe nanocrystals as biological luminescent label

Colloidal semiconductor nanocrystals have attracted considerable attention as a novel biological luminescent label. The bioinorganic conjugates of luminescent CdTe nanocrystals and protein, including CdTe/BSA (bovine serum albumin) and CdTe/MAB (mouse monoclonal antibody against hepatities B surface antigen), were formed via electrostatic/coordination self-assembly. Pure CdTe nanocrystals, CdTe/BSA and CdTe/MAB were used in the immunochromatographic assay experiments, respectively. And the results indicated that CdTe nanocrystals could be used and developed as a novel label with good stability, high sensitivity and facile determination of several analytes in immunochromatographic assay strips.     

Detection of paracetamol by capillary electrophoresis with chemiluminescence detection

Indirect detection of paracetamol was accomplished using a capillary electrophoresis-chemiluminescence (CE-CL) detection system, which was based on its inhibitory effect on a luminol-potassium hexacyanoferrate(III) (K₃[Fe(CN)₆]) CL reaction. Paracetamol migrated in the separation capillary, where it mixed with luminol included in the running buffer. The separation capillary outlet was inserted into the reaction capillary to reach the detection window. A four-way plexiglass joint held the separation capillary and the reaction capillary in place. K₃[Fe(CN)₆] solution was siphoned into a tee and flowed down to the detection window. CL was observed at the tip of the separation capillary outlet. The CL reaction of K₃[Fe(CN)₆] oxidized luminol was employed to provide the high and constant background. Since paracetamol inhibits the CL reaction, an inverted paracetamol peak can be detected, and the degree of CL suppression is proportional to the paracetamol concentration. Maximum CL signal was observed with an electrophoretic buffer of 30 mM sodium borate (pH 9.4) containing 0.5 mM luminol and an oxidizer solution of 0.8 mM K₃[Fe(CN)₆] in 100 mM NaOH solution. Under the optimal conditions, a linear range from 6.6 × 10⁻¹⁰ to 6.6 × 10⁻⁸ M (r = 0.9999), and a detection limit of 5.6 × 10⁻¹⁰ M (signal-to-noise ratio = 3) for paracetamol were achieved. The relative standard deviation (R.S.D.) of the peak area for 5.0 × 10⁻⁹ M of paracetamol (n = 11) was 2.9%. The applicability of the method for the analysis of pharmaceutical and biological samples was examined.     

Mechanisms and kinetics of humic acid adsorption onto chitosan-coated granules

Chitosan, a naturally abundant biopolymer, has widely been studied for metal adsorption from various aqueous solutions, but the extension of chitosan as an adsorbent to remove humic substances from water has seldom been explored. In this study, chitosan was coated on the surface of polyethyleneterephthalate (PET) granules through a dip and phase inversion process and was examined for humic acid removal in a series of batch adsorption experiments. Scanning electron microscopic (SEM) images showed that the PET granules were uniformly covered with a layer of chitosan and the chitosan layer possessed numerous open pores on the surface. Zeta potential study indicated that the chitosan-coated granules had positive zeta potentials at pH < 6.6 and negative zeta potentials at pH > 6.6. Adsorption of humic acid onto the chitosan-coated granules was found to be strongly pH-dependent. Significant amounts of humic acid were adsorbed under acidic and neutral pH conditions, but the adsorption capacity was reduced remarkably with increasing solution pH values. The adsorption isothermal data under various initial humic acid concentrations (at the same solution pH value) can be adequately modeled by the Langmuir and Freundlich models. X-ray photoelectron spectroscopy (XPS) revealed that the amino groups of the chitosan layer were protonated due to humic acid adsorption, suggesting the formation of organic complex between the protonated amino groups and humic acid. Kinetic study indicated that the adsorption process was transport-limited at low solution pH values, but became both transport- and attachment-limited at high solution pH values.     

溶液盐效应的气液色谱研究

本文将气液色谱法用于测定环丁砜含盐溶液中以烃、芳烃、氯代烃、醇和酮为溶质的盐效应常数,结果表明,大多数溶质的盐效应关系可用Setschenow方程描述;负离子的性质对盐效应的影响比正离子更重要;负离子的电子向氯代烃中氯原子3d空轨道的迁移作用对其k_s的影响很大。     

Molecular design of crown ethers. 21.(1,2) synthesis of novel double-armed benzo-15-crown-5 lariats and their complexation thermodynamics with light lanthanoid nitrates in acetonitrile

Three new disubstituted benzo-15-crown-5 derivatives (3-5) have been synthesized from 4',5'-bis(bromomethyl)benzo-15-crown-5 (2) and the corresponding alkanols in the presence of Na(2)S(2), and their complexation thermodynamics with light lanthanoid(III) nitrates (La-Gd) have been studied in anhydrous acetonitrile at 25 degrees C. Plots of K(S) against the reciprocal ionic diameter of lanthanoid exhibited monotonically declining pattern for the parent benzo-15-crown-5 (1) and 3 but showed a characteristic peak at Ce(3+) for 4 and 5. It is interesting to note that the simple extension of the alkyl side chains in 4 and 5 can alter the cation selectivity profiles of 1 and 3. Possessing two 2-oxapropyl groups, 3 gave a comparable K(S) for La(3+) but a significantly decreased K(S) for Ce(3+) compared with the corresponding values for 1, thus exhibiting an exceptionally high La(3+)/Ce(3+) selectivity of 11. Thermodynamically, the complexation of lanthanoid perchlorates with 1 is absolutely entropy-driven in acetonitrile, while the complexation of lanthanoid nitrates with 3-5 is primarily driven by exothermic enthalpy changes with accompanying moderate entropic gain or small entropic loss.     

表面引发原子转移自由基聚合方法合成Fe3O4/PMMA复合纳米微粒

采用表面引发原子转移自由基聚合方法合成了核壳结构的磁性高分子纳米微粒. 作为聚合反应引发剂的3-氯丙酸, 首先与油酸修饰的Fe3O4纳米微粒表面的部分油酸置换, 然后在Fe3O4纳米微粒表面引发甲基丙烯酸甲酯聚合, 合成的纳米复合材料用TEM, FTIR, XRD和DSC表征. 磁性测试结果表明, 所制备的磁性高分子纳米微粒仍具有超顺磁性, 但由于聚合物的存在, 其饱和磁化强度降低.     

Quantitative interrogation of protein co-aggregation using multi-color fluorogenic protein aggregation sensors

Co-aggregation of multiple pathogenic proteins is common in neurodegenerative diseases but deconvolution of such biochemical process is challenging. Herein, we developed a dual-color fluorogenic thermal shift assay to simultaneously report on the aggregation of two different proteins and quantitatively study their thermodynamic stability during co-aggregation. Expansion of spectral coverage was first achieved by developing multi-color fluorogenic protein aggregation sensors. Orthogonal detection was enabled by conjugating sensors of minimal fluorescence crosstalk to two different proteins via sortase-tag technology. Using this assay, we quantified shifts in melting temperatures in a heterozygous model protein system, revealing that the thermodynamic stability of wild-type proteins was significantly compromised by the mutant ones but not vice versa. We also examined how small molecule ligands selectively and differentially interfere with such interplay. Finally, we demonstrated these sensors are suited to visualize how different proteins exert influence on each other upon their co-aggregation in live cells.

A little leak will sink a great ship! We prepared a series of multi-color protein aggregation sensors and developed a dual-color thermal shift assay to simultaneously and quantitatively report on protein co-aggregation of two different proteins.