荧光光谱法研究左氧氟沙星、拉米夫定同时与牛血清白蛋白的相互作用

在模拟生理条件(pH值为7.40的Tris-HCl缓冲溶液)下,应用荧光光谱法研究了左氧氟沙星和拉米夫定对牛血清白蛋白(BSA)的荧光猝灭过程。结果表明:BSA与2种药物发生强烈猝灭,主要是静态猝灭;2种药物之间存在着相互作用,一种药物的存在提高了另一种药物与BSA之间结合的稳定性,减少了游离药物含量,药效降低。左氧氟沙星和拉米夫定之间的相互作用为临床合理用药提供了帮助。     

半代聚酰胺-胺型树状高分子对介孔氧化铝孔径调解作用

采用不同半代的聚酰胺-胺型树状高分子材料(PAMAM)作孔径调解剂,对介孔氧化铝进行孔径调解。研究结果表明,介孔氧化铝孔径大小与加入的PAMAM代数有关,加入的PAMAM代数低,形成的介孔孔径小,反之,代数高,形成的孔径大;且随代数的增大,孔径大小与相应代数的PAMAM尺寸越接近;研究结果还表明,加入PAMAM树状高分子不改变氧化铝的孔道结构和相结构,只起调节孔径大小和分布的作用。     

聚酰胺-胺树形分子的合成及其包覆的CdSe@CdS核壳结构量子点的性能研究

以乙二胺和丙烯酸甲酯为原料,采用扩散法合成了不同端基类型不同代数的聚酰胺-胺(PAMAM)树形高分子,并用红外光谱进行表征;以G5.0-NH2 PAMAM树形高分子为模板,以二甲基亚砜为溶剂,在常温下制备了稳定的PAMAM树形高分子包覆的CdSe@CdS核壳结构量子点,并用紫外-可见吸收光谱和荧光发射光谱进行表征。结果表明,适当厚度CdS的包覆修饰可以有效提高CdSe量子点的发光性能;与单一组分的CdSe量子点相比,CdSe@CdS核壳结构量子点的相对荧光强度最大提高约123 %。     

四环素猝灭聚酰胺-胺荧光机理及用于测定四环素含量

在pH 1. 0的溶液中,四环素对聚酰胺-胺(PAMAM)的荧光有显著的猝灭作用,结合紫外-可见光谱研究发现,动态猝灭、静态猝灭和能量转移猝灭共同导致了PAMAM的荧光猝灭现象。且四环素浓度在0. 000 25～0. 125 mg/mL范围内与lg(F_0/F)(F_0是加入四环素前PAMAM的荧光强度,F是加入猝灭剂四环素后PAMAM的荧光强度)存在线性关系,回归方程为lg(F_0/F)=11. 808c+0. 002 9 (c为四环素浓度,mg/mL),相关系数为0. 999 4,据此建立了一种通过猝灭PAMAM的荧光来定量测定四环素的方法。方法已被成功用于尿样中四环素的测定,加标回收率在96%～102%之间,方法检出限为12. 5 ng/mL。荧光猝灭法测定尿样中四环素的灵敏度高、检出限低、回收率高,能满足尿样中痕量四环素的测定要求。     

一种聚酰胺胺-苯甲醛树状大分子的合成及其荧光性能

首先以乙二胺为中心核,丙烯酸甲酯为支化单体合成了2.0代的聚酰胺胺树状大分子(PAMAM G 2.0),然后同苯甲醛在60℃水浴恒温反应48 h,得到了一种聚酰胺胺-苯甲醛树状大分子,用FTIR1、HNMR和13CNMR表征了合成产物的分子结构,结果和设计一致。该树状大分子能溶解于三氯甲烷,不溶于水、环己烷。对其荧光性能进行了研究,结果表明,溶液中的Fe3+对聚酰胺胺-苯甲醛树状大分子的荧光具有猝灭效应,并且荧光发射峰从436 nm红移到458 nm;溶液中的Zn2+对聚酰胺胺-苯甲醛树状大分子的荧光具有增强作用,同时荧光发射峰从436 nm蓝移到402 nm。     

甘氨酸-水杨醛席夫碱和邻菲咯啉混合配体的铜(Ⅱ)配合物与蛋白质相互作用的光谱学研究

在模拟人体生理条件下,综合利用荧光光谱、紫外吸收光谱、圆二色谱等方法研究了抗肿瘤药物甘氨酸-水杨醛席夫碱和邻菲咯啉混合配体的铜(Ⅱ)配合物与蛋白质相互作用。荧光光谱和紫外吸收光谱的分析表明铜(Ⅱ)配合物能有效猝灭BSA的内源荧光。猝灭过程同时表现出动态猝灭特征和静态猝灭特征,猝灭机制为混合机制。圆二色谱结果表明随着铜配物的加入,能引起BSA的构象发生改变,其α-螺旋含量有所减少,肽链结构有所伸展。     

光谱法研究新霉素与CuInS_2量子点的相互作用

采用水热法合成巯基乙酸修饰的CuInS_2量子点,通过紫外-可见吸收光谱、荧光光谱和共振瑞利散射光谱研究新霉素与CuInS_2量子点的相互作用,发现新霉素对CuInS_2量子点荧光具有较强的猝灭作用;并利用SternVolmer方程研究新霉素对CuInS_2量子点的荧光猝灭机理,结果表明属于静态猝灭。根据静态猝灭方程和热力学方程计算不同温度下新霉素与CuInS_2量子点反应的结合常数和热力学参数,结果表明新霉素与CuInS_2量子点之间有较强的结合力,且主要以范德华作用力和氢键作用力为主。     

光谱法研究新霉素与CuInS_2量子点的相互作用

采用水热法合成巯基乙酸修饰的CuInS_2量子点,通过紫外-可见吸收光谱、荧光光谱和共振瑞利散射光谱研究新霉素与CuInS_2量子点的相互作用,发现新霉素对CuInS_2量子点荧光具有较强的猝灭作用;并利用SternVolmer方程研究新霉素对CuInS_2量子点的荧光猝灭机理,结果表明属于静态猝灭。根据静态猝灭方程和热力学方程计算不同温度下新霉素与CuInS_2量子点反应的结合常数和热力学参数,结果表明新霉素与CuInS_2量子点之间有较强的结合力,且主要以范德华作用力和氢键作用力为主。     

水杨醛缩氨基硫脲配合物与牛血清蛋白的弱相互作用研究

本文合成了水杨醛缩氨基硫脲席夫碱配体并与锰、镉金属离子进行配位反应,合成了两种配合物。并通过红外光谱图分析,对配体及配合物的做了表征,分析了配合物可能存在的结构。选用荧光光谱法对席夫碱及其配合物和牛血清蛋白的弱相互作用进行了研究分析,结果表明该配体及其金属配合物与牛血清蛋白形成了基态复合物,引起了牛血清蛋白内源荧光猝灭现象,而具体何种荧光猝灭还有待进一步研究。     

两种抗血压类药物的合成及其与牛血清白蛋白的相互作用

合成了2,6-二甲基-4-苯基-1,4-二氢吡啶-3,5-二甲酸乙酯(药物分子a)和2,6-二甲基-4-甲基苯基-1,4-二氢吡啶-3,5-二甲酸乙酯(药物分子b),并用红外光谱、质谱和核磁共振氢谱表征了利用荧光光谱法研究了该药物分子与牛血清白蛋白(BSA)分子间的相互作用,并计算出不同温度下药物分子与BSA之间相互作用的动态猝灭常数、结合常数、结合位点数及热力学参数。实验结果表明:药物分子可以使牛血清白蛋白(BSA)发生荧光猝灭,其猝灭机理是形成基态复合物的静态猝灭;药物分子a与BSA的作用力主要是疏水力(ΔH0,ΔS0);药物分子b与BSA的作用力为氢键和范德华力(ΔH0,ΔS0)。     

Victrex® poly(ethersulfone) (PES) and Victrex® poly(etheretherketone) (PEEK)

Properties of two high performance engineering thermoplastics, amorphous polyethersulfone (PES) and semicrystalline polyetheretherketone (PEEK), are discussed. Both resins can be processed by conventional techniques, compounded with high performance fibers, and have high service temperature (up to 300°C). Due to the amorphous character PES can be dissolved and spray coated into metals.     

Photopyroelectric Spectroscopic Studies of ZnO-MnO(2)-Co(3)O(4)-V(2)O(5) Ceramics

Photopyroelectric (PPE) spectroscopy is a nondestructive tool that is used to study the optical properties of the ceramics (ZnO + 0.4MnO(2) + 0.4Co(3)O(4) + xV(2)O(5)), x = 0-1 mol%. Wavelength of incident light, modulated at 10 Hz, was in the range of 300-800 nm. PPE spectrum with reference to the doping level and sintering temperature is discussed. Optical energy band-gap (E(g)) was 2.11 eV for 0.3 mol% V(2)O(5) at a sintering temperature of 1025 °C as determined from the plot (ρhυ)(2)versushυ. With a further increase in V(2)O(5), the value of E(g) was found to be 2.59 eV. Steepness factor 'σ(A)' and 'σ(B)', which characterize the slope of exponential optical absorption, is discussed with reference to the variation of E(g). XRD, SEM and EDAX are also used for characterization of the ceramic. For this ceramic, the maximum relative density and grain size was observed to be 91.8% and 9.5 μm, respectively.     

(Ba_(1-α)Sr_α)_(4.8)(Sm_(0.7)La_(0.3))_(8.8)Ti_(18)O_(54)陶瓷的微波介电性能

采用固相合成法制备了(Ba(1-α)Srα)4.8(Sm0.7La0.3)8.8Ti18O54(α=0.1～0.5)系陶瓷,表征了该陶瓷的相组成和显微结构,测试了微波介电性能.结果表明:α=0.3时,(Ba(1-α)Srα)4.8(Sm0.7La0.3)8.8Ti18O54系陶瓷为单相的新钨青铜结构固溶体.α>0.3时,相继出现了第二相BaLa2Ti4O12和La0.66TiO2.993.随α的增加,(Ba(1-α)Srα)4.8(Sm0.7La0.3)8.8Ti18O54系陶瓷的相对介电常数(εr)先增大后有所波动,品质因数(Qf)先增大后减小,谐振频率温度系数(τf)单调减小.α=0.3时,在1 350℃烧结的陶瓷的微波介电性能最佳:εr=98.77,Qf=5184GHz,τf=10.9×10-6/℃,优于不掺杂的BaO-Sm2O3-TiO2陶瓷的.     

Calcium silicate hydrate (II) (“C-S-H(II)”)

This semicrystalline phase, originally named ‘calcium silicate hydrate(II)’ by Taylor (1950), has been studied with X-rays, electron optics, chemical investigation of silicate anion type, infrared spectra, and thermal methods. It is structurally related to jennite (C₉S₆H₁₁) and probably also to the fibrous CSH of cement pastes, the three phases forming a sequence of decreasing crystallinity. The specimen studied had approximate composition C₂SH_3.2 after standing over saturated CaCλ₂ at about 15°C. CSH(II) contains metasilicate chains and pyrosilicate groups and has a disordered layer structure. Much of the water can be lost reversibly without significant change in lattice parameters.     

Poly(butadiene-acrylic acid(g)acrylonitrile(g)acrylic acid)

Summary In the present work we describe, the synthesis and characterization of a new gel obtained by crosslinking a cooligomer of butadiene-acrylic acid (BuAA), by reaction with acrylonitrile and acrylic acid. The purified product was characterized by FTIR, elemental analyses and scanning electronic microscopy. The thermal properties were studied and swelling indexes were determined in different solvents and at different pH values. The capacity of poly(butadiene-acrylic acid(g)acrylonitrile(g)acrylic acid) [gel A] to separate different organic substances, such as amino acids and colorants, was determined.     

Thermal studies of blends of poly(phenylene sulfide) (PPS) with poly(phenylene sulfide sulfone) (PPSS) and with poly(phenylene sulfide ether) (PPSE)

The miscibilities of poly(phenylene) sulfide/poly(phenylene sulfide sulfone) (PPS/PPSS) and poly(phenylene) sulfide/poly(phenylene sulfide ether) (PPS/PPSE) blends were invesigated in terms of shifts of glass transition temperatures T_g of pure PPS, PPSS, a dn PPSE. The crystallization kinetics of PPS/PPSS blends was also studied as a function of molar composition. The PPS/PPSS and PPS/PPSE blends are respectively partially and fully miscible. PPSE shows a plasticizing effect on PPS as does PPS on PPSS, which necessarily improves te processibility in the respective systems. We can control T_g and melting temperature T_m of PPS by varying amounts of PPSE in blends. The melt crystallization temperature T_mc of PPS/PPSE blends was higher than that of the PPSE homopolymer. Therefore, these blends require shorter cycle times in processing than pure PPSE. The overall rate of crystallization for PPS/PPSS blends follows the Avrami equation with an exponent ?2. The maximal rate of crystallization for PPS/PPSS blends occurs at a temperatre higher by 10°C than that for PPS, while the crystallization half time t_1/2 is 4 times shorter. In the cold crystallization range, crystal growth rates increase and Avrami exponents decrease significantly as the temperature increases.     

Photooxidative stability of substituted poly(phenylene vinylene) (PPV) and poly(phenylene acetylene) (PPA)

The addition of side groups to improve the photooxidative stability of polymers used in polymer-based light-emitting diodes (LEDs) is explored. Infrared spectroscopy and computational chemistry techniques are used to study the effects of chemical substitution of the reactive vinylene moiety in poly(phenylene vinylene) (PPV). The bond order of the vinylene group in small oligomers is calculated using semiempirical techniques to assess the improvement in stability toward oxidants such as singlet oxygen. We find that PPV dimers allow relative comparisons across a range of possible substitutions. Experimental results correlate well with these calculations. The addition of electron-withdrawing substituents, such as nitrile groups, to the vinylene moiety is found to be particularly effective in reducing the reactivity of alkoxy-substituted PPV toward singlet oxygen. The photooxidative stability of a poly(phenylene acetylene) (PPA) derivative is also studied. It appears that this family of polymers is more stable toward photooxidation than are its PPV analogs. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 69: 2451–2458, 1998     

Chemical cross-linking of conducting poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) using poly(ethylene oxide) (PEO)

Hybrid films of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) were prepared with different molecular weights of poly(ethylene oxide) (PEO). The cross-linking reaction between PEO and PEDOT:PSS was performed at high temperature and confirmed by using differential scanning calorimeter (DSC), contact angle measurement, and solid-state ¹H NMR. The effect of chemical reaction on the conductivity and morphology of these hybrid films was studied by using 4-point probe and atomic force microscope (AFM), respectively. As-spun PEO/PEDOT:PSS films have lower electric conductivity due to the addition of nonconductive PEO, and exhibits no molecular weight dependence on conductivity. After chemical cross-linking reaction at high temperature, only PEDOT:PSS films with lowest molecular weight PEO additives show enhanced conductivity with increasing reaction time. AFM result indicates that the heat-treated PEO/PEDOT:PSS hybrid films show grain-like morphology compared to ethylene glycol treated PEDOT:PSS films which shows continuous PEDOT domain. In the present work we demonstrate that the cross-linking reaction can be used to improve the wet stability of PEDOT:PSS nanofiber, showing good water resistance and excellent dimensional stability.