玻璃基质微流控芯片用于DNA片段的分离和C677T基因突变的快速检测

基于微加工方法,在一般实验条件下,成功地制备了玻璃芯片。利用水溶性聚合物对玻璃通道进行动态修饰,从而抑制了DNA分子的吸附作用,并成功地用于DNA片段的分离和四氢叶酸还原酶基因(MTHFR)中C677T的突变检测。     

重要传感材料荧光共轭聚合物PPESO3的一种新的简便合成路线

本文提出了一种新的简便得多的合成路线, 既避免了BBr3的使用, 又简化了反应步骤, 使PPESO3的合成简单易行, 为更广泛地对其进行研究与应用提供了便利条件. 此外, 本文还研究了PPESO3与非离子表面活性剂(聚乙烯吡咯烷酮, PVP)之间的相互作用, 结果表明, PVP与PPESO3形成了稳定的络合体, 可以有效地打破聚合物在水溶液中的聚集, 提高荧光量子产率.     

表面活性剂对LiNi0.80Co0.15Al0.05O2的结构和性能影响

在共沉淀过程中添加表面活性剂聚乙二醇(PEG)或聚乙烯吡咯烷酮(PVP)分别合成类球形Ni_(0.80)Co_(0.15)Al_(0.05)(OH)_2前驱体,再与氢氧化锂(LiOH·H_2O)氧化煅烧得到LiNi_(0.80)Co_(0.15)Al_(0.05)O_2(NCA)三元正极材料。利用X射线衍射(XRD)、扫描电镜(SEM)、透射电子显微镜(TEM)、循环伏安(CV)、交流阻抗(EIS)和充放电循环测试等对材料的结构、形貌、电化学性能等进行表征。结果表明:PEG和PVP的添加不影响材料中Ni、Co和Al元素的比例,能够促进一次晶粒长大和提高振实密度,能够促进正极材料层状结构发育进而提高正极材料的电化学性能。添加PEG、添加PVP和未添加表面活性剂合成正极材料的振实密度分别为2.07、1.86和1.40 g·cm~(-3),在0.2C充放电过程中首次放电比容量分别为210.8、188.9和173.0 mAh·g~(-1),以0.2C充电1C放电循环100次后电池容量保持率分别为78.8%、93.2%和82.7%,添加PEG和PVP的NCA材料表现出良好的电化学性能。     

Molecularly engineered graphene surfaces for sensing applications: A review

Graphene is scientifically and commercially important because of its unique molecular structure which is monoatomic in thickness, rigorously two-dimensional and highly conjugated. Consequently, graphene exhibits exceptional electrical, optical, thermal and mechanical properties. Herein, we critically discuss the surface modification of graphene, the specific advantages that graphene-based materials can provide over other materials in sensor research and their related chemical and electrochemical properties. Furthermore, we describe the latest developments in the use of these materials for sensing technology, including chemical sensors and biosensors and their applications in security, environmental safety and diseases detection and diagnosis.     

配体保护下的Au_(20)团簇吸附和活化CO的理论研究

用密度泛函理论方法计算了CO分子吸附在有机配体聚乙烯吡咯烷酮poly(N-vinyl-2-pyrrolidone)(PVP)保护下的Au20团簇上的稳定构型的结构和性质。配体PVP通过物理吸附主要作用于Au20团簇的顶点位置。与Au20比较,配体的存在有利于CO的吸附和活化,其根本原因是PVP和CO在Au20表面分别作为供电子和吸电子基团产生的协同效应。中性及阴离子Au20团簇对配体和CO的吸附强度不同,前者对PVP吸附作用较强,后者对CO的吸附和活化作用较强。     

Interaction between sodium dodecyl sulfate (SDS) and polyvinylpyrrolidone (PVP) investigated with forward and reverse component addition protocols employing tensiometric, conductometric, microcalorimetric, electrokinetic, and DLS techniques

The interaction between polyvinylpyrrolidone (PVP) and sodium dodecyl sulfate (SDS) after the procedure of addition of the surfactant to polymer and the reverse procedure of addition of polymer to SDS micelles has been studied by tensiometric, conductometric, and microcalorimetric methods. The results have been analyzed and correlated with reference to SDS interfacial adsorption, association, and binding to PVP. Two aggregation states of SDS in presence of PVP have been found. The enthalpies of formation of SDS aggregates/micelles and their binding to the polymer have been evaluated. The interaction of PVP with SDS at concentrations below its critical micellar concentration (CMC) and above have evidenced distinctions. The forward addition protocol (FAP, SDS addition to PVP) and reverse addition protocol (RAP, PVP addition to SDS) have shown similarities and differences. Electrokinetic measurements have evidenced the interacted (SDS–PVP) colloidal products to possess negative zeta potential in the range of −39 to −65 mV. The hydrodynamic diameters of the PVP–SDS dispersion obtained from DLS measurements have ranged between 60 and 160 nm. Both zeta potential and hydrodynamic diameter have depended on [SDS] showing a maximum for the former at twice the critical micellar concentration of SDS.     

MICELLIZATION STUDIES OF DODECYL BENZENESULFONIC ACID AND ITS INTERACTION WITH POLYVINYLPYRROLIDONE

Dodecyl benzenesulfonic acid (DBSA) surfactant was used in the present study to find the effect of concentration on its electrical conductance in solution from 293-323K above and below the critical micelle concentration (CMC). The micellization parameters i.e. degree of counter ion binding (β), aggregation number (n) and number of counter ion micelle(m) were measured. The interaction of DBSA with polyvinylpyrrolidone (PVP) was also studied at 293K throughconductance and surface tension measure ments. A number of important parameters i.e. critical aggregation concentration (CAC), Gibb‘s free energy (△G) and binding ratio (R) were determined and the effect of NaCl on the CAC and polymer saturation point (PSP) was also investigated.     

Encapsulation and characterization of flurbiprofen loaded poly(є-caprolactone)–poly(vinylpyrrolidone) blend micropheres by solvent evaporation method

Flurbiprofen loaded PCL/PVP blend microspheres were prepared by o/w solvent evaporation method using various concentrations of gelatin as emulsifying agent. Microsphere recovery decreased with a decrease in the concentration of the emulsifier in the dispersion. Encapsulation efficiency and drug loading of microspheres increased with decrease in concentration of emulsifying agent. Hydration rate, encapsulation efficiency and drug loading of microspheres increased with increase in concentration of PVP. Rheological properties showed free flowing nature of microspheres. SEM (Scanning electron microscope) revealed microspheres were discrete, spherical and became porous with decrease in concentration of emulsifying agent but smooth with higher concentration of emulsifying agent. FTIR (Fourier transform infrared spectroscopy) spectra of pure and encapsulated flurbiprofen in all formulation showed no significant difference in characteristic peaks, suggesting stability of flurbiprofen during encapsulation process. X-RD (X-ray powder diffractometry) of pure flurbiprofen shows sharp peaks, which decreases on encapsulation, indicating dispersion at molecular level and hence decrease in the crystallinity of drug in microspheres. Microspheres showed an enteric nature at pH 1.2 and a sustained release pattern at pH 6.8. Rapid drug release was observed in microspheres with higher concentration of PVP (polyvinylpyrrolidone), PVP acts as channeling agent. Formulation with low concentration of emulsifying agent also showed a fast release due to porous structure. Drug release kinetics followed zero order at pH 1.2 while at pH 6.8 Higuchi model was best fitted and was found non fickian.     

Design and construction of a 110 W green laser for medical application

In this paper, the design and the construction of a high-power side-diode-pumped Nd:YAG solid-state laser at repetition rates of 6 and 10 kHz has been presented. Second harmonic of the Nd:YAG laser with green light at 532 nm, with an average power of 111.5 W at 10 kHz repetition rate, and with 90 ns pulse duration, has been obtained by the nonlinear crystal of KTP with 59% conversion efficiency and 12% diode-to-green optical–optical efficiency in the linear resonator. Beam spot size and divergence is 4 mm and 8 mrad, respectively. The laser stability is about 97%. As a medical application of this laser, investigation of degree of effectiveness and penetration depth of laser on adenomas of resected prostate after open prostatectomy has been done.