Kinetic-catalytic determination of osmium by fluorescence quenching with salicylfluorone and hydrogen peroxide

A highly sensitive and selective fluorescence-quenching kinetic method is proposed for the determination of trace osmium(IV), based on the catalytic effect of osmium(IV) on the salicylfluorone (_ex = 510 nm, _em = 535 nm)-H₂O₂ system at pH 9.3–9.6. Using the fixed time method, osmium(IV) in the range 0.008–0.6 ng/ml can be determined. The detection limit is 0.006 ng/ml. Over thirty anions and cations, including other platinum metal ions, do not interfere, even when present in large excess. The method has been applied successfully for the determination of osmium in a series of synthetic mixtures and refined ore with relative standard deviations of 2–6%.     

Frontal polymerization synthesis and characterization of temperature- and pH-sensitive hydrogels

The temperature- and pH-sensitive hydrogels, poly(N-isopropylacrylamide-co-acrylic acid) (P(NIPAM-co-AAc)), were synthesized via frontal polymerization (FP). The reaction components have been varied in order to find their influences on frontal parameters and copolymer features. The results showed that front velocity and front temperature were dependent on the initiator concentration, reactant dilution, and NIPMA/AAc molar ratio. In addition, the morphology and sensitive behavior of the FP hydrogels were mainly affected by monomers’ ratio. Namely, the pore size, swelling abilities, LCST, and response kinetics of copolymer hydrogels obviously increased with the increasing acrylic acid concentration; however, they slightly changed with varying of amounts of initiator and solvent. Finally, in comparison with the hydrogels prepared by conventional batch polymerization, the ones synthesized by frontal polymerization exhibited more homogeneous chain composition and improved microstructure and response ability.     

A rapid and effective method for silver staining of PCR products separated in polyacrylamide gels

With the development of molecular quantitative genetics, particularly, genetic linkage map construction, quantitative trait loci mapping or genes fine mapping and association analysis etc., more and more PCR products separated in polyacrylamide gels need to be silver‐stained. However, conventional silver‐staining procedures are complicated and time‐consuming as they require a lot of preparation and handling of several solutions prior to use. In this study, a simple and rapid protocol for silver staining of PCR products was developed. The number of steps was reduced compared to conventional protocols, thus achieving detection of PCR products in 7 min, saving time and resources. Fixation and staining solution and developing solution in present staining procedure allowed a reutilization for 12 and 8 times, respectively, reducing the cost greatly. Meanwhile, the sensitivity was significantly improved with the improved method and the minimum of 0.097 ng/μL of DNA amount can be detected in denaturing polyacrylamide gel. The protocol developed in this study will facilitate the development of molecular quantitative genetics.     

基于CIC的数字正交锁相放大器的甲烷检测实验研究

针对甲烷在大气中背景气体成分复杂、检测难度大、稳定性差等问题,本文基于可调谐二极管激光吸收光谱技术和波长调制光谱技术,将积分梳状滤波器与有限脉冲响应滤波器相结合应用于数字正交锁相放大器,开展大气中甲烷气体的痕量检测实验研究.实验表明,与传统的数字正交锁相放大器相比较,改进的数字正交锁相放大器提取的二次谐波信号的信噪比从...     

p型G aSb窗口层在热光伏电池中的应用研究

为了提高GaSb热光伏电池的转换效率,在电池结构中引入p+-GaSb窗口层,研究了生长基底、衬底温度和反应物源温度对p+-GaSb薄膜性能的影响,并优化了电池结构中p+-GaSb窗口层的厚度和掺杂浓度.实验结果表明,生长基底和温度等制备参数影响着p+-GaSb薄膜的结构特性和电学特性,而且,较薄的高掺杂p+-GaSb层有利于提高电池性能.通过测试和仿真,热光伏电池的转换效率达到9.49;(AM1.5测试)和20.34;(AFORS-HET仿真).     

热力学变化过程方向的完整判据

目前物理化学教科书中的自发过程方向与限度判据,只能对常见自发过程作判断,不能对含有非体积功的各类过程做出判断。笔者从热力学第二定律的理论基础克劳修斯不等式入手,通过自发变化熵判据的演绎过程,找到了3个判据不完整性的原因所在,给出了完整方向性判据的解决方案。应用表明,完整的方向与限度判据可适用于各类热力学变化过程。     

植物样品中痕量碘的测定

研究了植物样品中痕量碘的测定条件.样品用艾斯卡熔剂于550 ℃灰化分解,以乙酸-乙酸钠缓冲体系,控制适当的酸度,利用4,4′-四甲基二胺基甲烷(简称四碱)-氯胺T体系进行催化比色测定,通过对实验温度的严格控制,以及增加样量,较大地改善了催化光度法测定痕量碘的稳定性和灵敏度.结果表明,在选定实验条件下,测定精密度(n=1...     

Modified Alternating Direction Methods for the Modified Multiple-Sets Split Feasibility Problems

In this paper, we propose two new multiple-sets split feasibility problem models and new solution methods. The first model is more separable than the original one, which enables us to apply a modified alternating direction method with parallel steps to solve it. Then, to overcome the difficulty of computing projections onto the constraint sets, a special version of this modified method with the strategy of projection onto half-space is given. The second model consists in finding a least Euclidean norm solution of the multiple-sets split feasibility problem, for which we provide another modified alternating direction method. Numerical results presented at the last show the efficiency of our methods.     

抗肿瘤缺氧诱导因子-1的小分子抑制剂

肿瘤的缺氧微环境与其增殖、分化、血管生成、能量代谢、耐药性的发生以及患者预后状况密切相关。缺氧诱导因子1(Hypoxia-inducible factor 1, HIF-1)是细胞适应缺氧环境的重要转录因子和调控蛋白,通过调控下游靶基因如EPO、VEGF、GLUT等的表达,促进血管新生及有氧糖酵解以适应缺氧的环境,进而影响肿瘤细胞代谢、血管生成和肿瘤转移等。因此,开发以HIF-1为靶标的小分子抑制剂药物有望成为一种有效的肿瘤治疗方法。本文就HIF-1小分子抑制剂在肿瘤学研究中的进展进行综述,旨在为靶向HIF-1抗肿瘤药物的研发提供新思路。