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排序方式: 共有122条查询结果,搜索用时 15 毫秒
111.
Xueling Li Chi-chun Fong Minghui Huang Huimin Cao Jianlong Zhao Mengsu Yang 《Mikrochimica acta》2008,160(1-2):253-260
A high-performance amperometric glucose biosensor was developed, based on immobilization of glucose oxidase (GOx) on a copper
(Cu) nanoparticles/chitosan (CHIT)/carbon nanotube (CNT)-modified glassy carbon (GC) electrode. The Cu and CNT had a synergistic
electrocatalytic effect toward the reduction of hydrogen peroxide in the matrix of biopolymer CHIT. The Cu/CHIT/CNT modified
GC electrode could amplify the reduction current of hydrogen peroxide greatly. Besides, the Cu/CHIT/CNT modified GC electrode
reduces hydrogen peroxide at a much lower applied potential and inhibit the responses of interferents. With GOx as an enzyme
model, a new glucose biosensor was fabricated. The sensitivity of the sensor is due not only to the large microscopic area
but also to the high efficiency of transformation of H2O2 generated by enzymatic reaction to current signal. The biosensor exhibited excellent sensitivity (the detection limit is
down to 0.02 mM), fast response time (less than 4 sec), wide linear range (from 0.05 to 12 mM), and perfect selectivity.
Correspondence: Wanzhi Wei, State key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering,
Hunan University, Changsha 410082, China 相似文献
112.
Nan Zhang Shanshan Shi Shaobin Lin Zhaochen Bai Xiaohua Ling Jun Gao Ruiling Yan Xueling Ou 《Electrophoresis》2023,44(19-20):1569-1578
The need to identify a missing person (MP) through kinship analysis of DNA samples found at a crime scene has become increasingly prevalent. DNA samples from MPs can be severely degraded, contain little DNA and mixed with other contributors, which often makes it difficult to apply conventional methods in practice. This study developed a massively parallel sequencing–based panel that contains 1661 single-nucleotide polymorphisms (SNPs) with low minor allele frequencies (MAFs) (averaged at 0.0613) in the Chinese Han population, and the strategy for relationship inference from DNA mixtures comprising different numbers of contributors (NOCs) and of varying allele dropout probabilities. Based on the simulated dataset and genotyping results of 42 artificial DNA mixtures (NOC = 2–4), it was observed that the present SNP panel was sufficient for balanced mixtures when referenced to the closest relatives (parents/offspring and full siblings). When the mixture profiles suffered from dropout, incorrect assignments were markedly associated with relatedness, NOC and the dropout level. We, therefore, indicate that SNPs with low MAFs could be reliably interpreted for MP identification through the kinship analysis of complex DNA mixtures. Further studies should be extended to more possible scenarios to test the feasibility of this present approach. 相似文献
113.
High-melting hydrocarbon waxes (melting point: > 80 ℃), consisting of saturated alkanes with carbon numbers greater than 40, exhibit unique features including high melting points, high stability, low penetration, high viscosity, as well as good wear resistance and hardness. These features make high-melting waxes suitable for use in foods, cosmetics, materials processing, electronic machinery, national defense, aviation, medical fields, etc. Considering the fast growth of technology and the electronics industry, the world's economy relies on the production and utilization of high-quality high-melting waxes. However, most waxes in the world's current markets are prepared from mineral oils, and such commercial waxes have melting points in the range of 50–70 ℃. Considering the rapid consumption of high-melting waxes and specialty waxes, their supply insufficiency is anticipated to exceed 700000 t. High-melting waxes are divided into polyethylene (PE) wax and Fischer-Tropsch synthesis (FTS) wax, based on synthesis methodology. PE wax can be obtained via the polymerization of ethylene and can also be prepared via the thermal or catalytic cracking of plastics. PE cracking to form waxes, with the advantage of low cost, can effectively solve the problem of "white pollution" and make use of existing catalytic cracking units. However, this process results in high energy consumption to achieve waste polymer depolymerization and exhibits some drawbacks, such as a wide carbon number distribution and high impurity content in the obtained PE waxes. However, there are some new methods for synthesizing PE waxes, such as cross alkane metathesis. The FTS, which uses carbon monoxide and hydrogen as raw materials, realizes the synthesis of waxes through carbon chain growth. Although the high-melting FTS waxes display excellent performance and the technology is gradually maturing, FTS waxes with different melting points are produced by rectification of products with various carbon chain lengths. Nonetheless, PE and FTS waxes are widely used in various industries because of their excellent properties. However, their synthesis is based on petroleum and coal-derived chemical products. Biomass-derived waxes have a narrow melting range due to their precise carbon chain growth process. Based on different application demands, small biomass platform molecules can be functionalized to fabricate biomass-derived waxes with special functions. More importantly, the biomass-based synthesis route is sustainable and in-line with the global values for mitigating carbon dioxide emissions and achieving carbon neutrality. This review discusses the recent advances in the synthesis techniques for high-melting waxes, including PE waxes, FTS waxes, and biomass-derived waxes. Furthermore, the catalysts and reaction mechanisms involved in the synthesis of high-melting waxes are discussed in detail. Finally, the perspectives and trends of high-melting waxes are reviewed to promote the emergence of new processes and technical routes.
相似文献
114.
浅析高校化学实验室废弃物的综合处理 总被引:1,自引:0,他引:1
化学实验室的环境污染问题不容忽视,必须防患于未然。实验过程中产生各种废气、废水和固体废物等污染物,对人体的危害极大。本文分析了目前我国高校化学实验室"三废"污染的现状,简单阐明了造成化学实验室环境污染的主要原因,同时提出了实验室污染的防治措施。 相似文献
115.
利用Avery-Henderson不动点定理,讨论了时间测度链上一类非线性边值问题正解的存在性,并在一定条件下得到两个正解的存在性结果,继而利用Legget-Williams不动点定理将其两个正解推广到三个解的情况,同时利用一种等价转化,给出二阶非线性边值问题格林函数的求法,使其求法一般化. 相似文献
116.
Xiaoyun Fan Shilie Pan Xueling Hou Xuelin Tian Jian Han 《Journal of Crystal Growth》2010,312(15):2263-2266
Colorless and transparent Na3VO2B6O11 (NVB) crystal has been grown by the top seeded solution growth method using NaVO3 as the flux at cooling rates of 0.8–1.5 °C/day, in the temperature range 610–650 °C. A well-developed morphology of the crystals was observed and analyzed. The grown crystals were characterized by powder X-ray diffraction (PXRD), infrared spectroscopy and second harmonic generation (SHG) test. 相似文献
117.
Yuanqing Song Chuandong Sun Chenxu Tian Hao Ming Yanjun Wang Wenkai Liu Nan He Xueling He Mingming Ding Jiehua Li Feng Luo Hong Tan Qiang Fu 《Chemical science》2022,13(18):5353
The construction of polyurethanes (PUs) with sequence-controlled block structures remains a serious challenge. Here, we report the precise synthesis of PUs with desirable molecular weight, narrow molecular weight distribution, and controlled block sequences from commercially available monomers. The synthetic procedure is derived from a liquid-phase synthetic methodology, which involves diisocyanate-based iterative protocols in combination with a convergent strategy. Furthermore, a pair of multifunctional PUs with different sequence orders of cationic and anion segments were prepared. We show that the sequence order of functional segments presents an impact on the self-assembly behavior and results in unexpected surface charges of assembled micelles, thereby affecting the protein absorption, cell internalization, biodistribution and antitumor effect of the nanocarriers in vitro and in vivo. This work provides a versatile platform for the development of precise multiblock PUs with structural complexity and functional diversity, and will greatly facilitate the clinical translation of PUs in biomedicine.Polyurethanes (PUs) with different segment sequence orders are prepared using a precise synthetic platform, and the sequence order of functional segments plays a crucial role in regulating the surface charges and performance of nano-drug carriers. 相似文献
118.
Dongge Yin Xueling Hu Mengru Cai Kaixin Wang Hulinyue Peng Jie Bai Yvchen Xv Tingting Fu Xiaoxv Dong Jian Ni Xingbin Yin 《Molecules (Basel, Switzerland)》2022,27(12)
Curcumin (CUR) has a bright future in the treatment of cancer as a natural active ingredient with great potential. However, curcumin has a low solubility, which limits its clinical application. In this study, IRMOF-10 was created by the direct addition of triethylamine, CUR was loaded into IRMOF-10 using the solvent adsorption method, and the two were characterized using a scanning electron microscope (SEM), X-ray diffraction (XRD), dynamic light scattering (DLS), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TG) methods, and Brunauer–Emmett–Teller (BET) analysis. We also used the MTT method, 4′,6-diamidino-2-phenylindole (DAPI) staining, the annexin V/PI method, cellular uptake, reactive oxygen species (ROS), and the mitochondrial membrane potential (MMP) to perform a safety analysis and anticancer activity study of IRMOF-10 and CUR@IRMOF-10 on HepG2 cells. Our results showed that CUR@IRMOF-10 had a CUR load of 63.96%, with an obvious slow-release phenomenon. The CUR levels released under different conditions at 60 h were 33.58% (pH 7.4) and 31.86% (pH 5.5). Cell experiments proved that IRMOF-10 was biologically safe and could promote curcumin entering the nucleus, causing a series of reactions, such as an increase in reactive oxygen species and a decrease in the mitochondrial membrane potential, thereby leading to cell apoptosis. In summary, IRMOF-10 is an excellent drug carrier and CUR@IRMOF-10 is an effective anti-liver cancer sustained-release preparation. 相似文献
119.
120.
Dr. Jingyu Guo Junben Huang Abudukadi Tudi Prof. Xueling Hou Dr. Shujuan Han Prof. Zhihua Yang Prof. Shilie Pan 《Angewandte Chemie (International ed. in English)》2023,62(28):e202304238
It is important to establish and clarify the relationship between stereochemically active lone pairs and birefringence, since it is one of the significantly effective routes to explore birefringent crystals by introducing Sn-centered polyhedra with stereochemically active lone pairs. Herein, four tin(II)-based ternary halides A3SnCl5 and ASn2Cl5 (A=NH4 and Rb) have been synthesized successfully. The experimental birefringence of Rb3SnCl5 and RbSn2Cl5 is larger than or equal to 0.046 and 0.123@546 nm, respectively. Through investigating the alkali or alkaline-earth metal tin(II)-based ternary halides, the structure-performance relationship has been concluded between stereochemically active lone pairs and optical anisotropy. It is beneficial to the analysis and prediction of birefringence in tin-based halides and provides a guide for exploring tin(II)-based optoelectronic functional materials. 相似文献