改性Ge/TiO2催化剂降解环丙沙星的研究

目的 抗生素的大量使用和肆意排放给人类生存环境和身体健康带来极大危害。制备合理、有效、无二次污染的光催化剂是光催化处理抗生素废水技术的一种重要手段。方法 采用溶胶-凝胶法制备掺杂Ge的改性Ge/TiO2催化剂,分析其在不同环境条件下对废水中环丙沙星(ciprofloxacin, CPLX)的光催化降解效果,探讨不同催化剂浓度、光源、光照时间、pH、水中共存离子Cl-、NO3-浓度,5个因素对环丙沙星降解率的影响。结果 改性Ge/TiO2催化剂具有良好的光催化降解性能,反应符合L-H动力学方程,降解过程表现为伪一级反应。在紫外光下,环丙沙星初始浓度为10mg/L,pH为7.5,催化剂浓度1.5g/L,光照时间150min时,降解率最高。推测了改性Ge/TiO2催化剂光催化机理,反应基本发生在催化剂表面,降解环丙沙星过程主要是自由基反应。结论 在最佳条件下,对环丙沙星降解率达到97.99%。     

光催化降解对氟苯氧乙酸的规律研究

以Pt／TiO2为光催化剂,研究了废水中对氟苯氧乙酸的光催化降解反应。考察了反应时间、溶液初始pH值以及污染物初始浓度对光催化反应的影响。实验表明,反应3h内,氟离子平均检出速率为2.64＆#215;10-5mol／（L· h）;在反应4～7h内,氟离子平均检出速率为5.38×10^-5mol／（ L· h）。反应液的紫外光谱图显示对氟苯氧乙酸浓度不断下降。在溶液初始pH值为3.44～4.95时,光催化生成氟离子的速率最大,在碱性范围内,氟离子的生成速率为零。当C0（对氟苯氧乙酸）＜1.00×10^-3 mol· L-1时,光催化降解反应速率随着对氟苯氧乙酸初始浓度的增大而急剧增大;当C0（对氟苯氧乙酸）＞8.00×10^-3 mol· L -1时,光催化降解速率与污染物初始浓度无关。     

草乌甲素的降解动力学

目的研究草乌甲素的降解动力学,考察影响草乌甲素降解的因素。方法采用经典恒温法进行实验,以高效液相色谱法测定草乌甲素的含量。结果草乌甲素的降解呈伪一级动力学,主要受OH-催化。温度升高,草乌甲素降解速率增加。草乌甲素的最稳pH值范围为3~5。草乌甲素在pH 7~9时的降解反应活化能分别为148.04、137.65和102.36 kJ.mol-1,室温(25℃)时的t0.9分别为1 054.00、95.82、7.42 h。碱性条件下,离子强度增加,表观降解速率常数减小。结论草乌甲素的降解反应为伪一级反应。温度、pH值和离子强度显著影响草乌甲素的降解反应。     

唐松草新碱水溶液的氧化降解动力学研究

本文研究了唐松草新碱在水溶液中的氧化降解动力学。考查了pH值、离子强度、温度和氧含量的影响,水溶液中的氧化降解速率常数由荧光法测定。结果表明,唐松草新碱在过量氧存在下,其氧化降解反应服从假一级反应动力学方程式,速率常数可由下式表示:其速率常数主要受介质的pH值和氧含量的影响,在pH 7.2条件下没有观测到原盐效应。     

穿琥宁注射液降解动力学研究

目的：研究穿琥宁注射液在不同pH值、不同温度、不同光照条件下降解反应的动力学参数。方法：用高效液相色谱法测定含量，井运用经典恒温法、多元线性模型探讨其稳定性，用阿累尼乌斯公式预测其有效期和活化能。结果：穿琥宁注射液的降解反应为假一级动力学。结论：穿琥宁注射液在pH值6．0时最稳定，有效期为24个月。为进一步探讨其阵解机制提供必要的实验结果和数据。     

胰岛素溶液化学稳定性研究

本文用反相高效液相色谱法(RP-HPLC)和高效液相凝胶层析法(GF-HPLC)研究了pH值对胰岛素溶液化学稳定性的影响。稳定性实验采用经典恒温法。实验结果表明pH值是影响胰岛素溶液化学稳定性的重要因素,在酸性溶液中降解反应速率随pH值的降低而增大;而在碱性溶液中则随pH值的降低而减小,即溶液pH值接近胰岛素等电点时其稳定性最好。胰岛素溶液加热降解反应规律符合一级动力学方程。     

变温加速法解析阿司匹林降解反应的动力学参数

目的:采用变温加速法测定药物降解反应的动力学参数.并与等温加速法相比较,考察该方法的准确性.方法:以阿司匹林为模型药物,在设定的实验条件下,从温度变化过程中药物的残存率与时间的关系入手,根据化学动力学的原理,采用非线性最小二乘法解析其降解反应的动力学参数Ea及A.结果:阿司匹林的降解反应属准一级反应.在pH 2、pH 4和pH 6的条件下,采用变温加速法求得阿司匹林的降解反应的Ea分别是:16.13、18.19和23.87 kJ/mol(升温速率为5℃/h和10℃/h的平均值),等温加速法测得的Ea分别为16.12、18.01和23.93 kJ/mol.结论:采用变温加速法与等温加速法测得的药物降解反应的动力学参数基本一致.与等温加速法相比,变温加速法测定药物的稳定性具有迅速、可靠、简便、用样量少等特点.     

TiO_2光催化降解水中盐酸左氧氟沙星

目的以锐钛型TiO_2为光催化剂,研究其对水中盐酸左氧氟沙星的光催化降解性能。方法采用单因素实验方法考察溶液pH值、TiO_2用量、药物初始浓度和金属离子对盐酸左氧氟沙星光催化降解的影响规律。结果当TiO_2用量为4.0 g·L~(-1)、药物初始质量浓度为6 mg·L~(-1),pH=7.0,光照反应10 min时,盐酸左氧氟沙星的降解率在96%以上;溶液中的Na~+、Zn~(2+)、Fe~(3+)对盐酸左氧氟沙星降解具有抑制作用,抑制作用从高到低的顺序为Fe~(3+)、Zn~(2+)、Na~+。结论锐钛型TiO_2能够有效地降解水中的盐酸左氧氟沙星药物。     

溶菌酶对壳聚糖降解的研究

对溶菌酶降解壳聚糖的过程进行了研究。探讨了降解过程的粘度变化、温度、pH值、反应时间、酶浓度、壳聚糖浓度以及壳聚糖的脱乙酰化度对酶促反应速度的影响。实验结果表明，以壳聚糖为底物的溶菌要不得的催化是属米氏酶的特征，该酶促反应的最适宜温度为50℃，适宜pH值是6.0左右，壳聚糖的脱乙酰度越低降解速度越快。产品经高效液相色谱测定相对分子质量低于1万，相对分子质量组分集中，水溶性良好。     

响应面优化Ge/TiO2催化剂降解环丙沙星的初步研究

目的 抗生素的大量使用和肆意排放给人类生存环境和身体健康带来极大危害。制备合理、有效、无二次污染的光催化剂是光催化处理抗生素废水技术的一种重要手段。方法 采用溶胶法Ge4+为掺杂离子改性TiO2，制备Ge/TiO2催化剂，并利用响应面法(response surface method, RSM)对Ge/TiO2催化剂降解废水中环丙沙星的过程进行优化，探讨煅烧温度、掺杂量、煅烧时间3个因素对环丙沙星降解效果的影响。在单因素试验的基础上，进行响应面优化试验。结果 3个因素均对Ge/TiO2降解性能均有影响，其影响显著性为：煅烧温度>掺杂量>煅烧时间；确定出Ge/TiO2催化剂的最佳制备条件为：煅烧温度为571℃、掺杂量为0.26%，煅烧时间为3.11h。结论 在最优条件下，对环丙沙星降解率达到96.98%，与预测最佳结果97.09%基本符合。     

Photocatalytic activity of AgCl/SnO2 prepared by one-pot green synthesis

A green synthesis of AgCl/SnO₂ was successfully achieved by precipitation in a natural alkaline solution extracted from wood ash. In this work, the AgCl was prepared through a reaction between Cl^- ion, a counter ion from SnCl₄.5H₂O, and Ag⁺ ion from AgNO₃. The products were characterized by X-ray diffractometry (XRD), transmission electron microscopy (SEM), UV–Vis diffuse reflectance spectrometry, and photoelectron spectroscopy (XPS). The presence of AgCl increased the visible light absorption ability of the AgCl/SnO₂ composite and its photocatalytic activity was enhanced under visible light irradiation. Under visible light irradiation, 10%AgCl-modified SnO₂ annealed at 500 °C for 1 h showed the highest photocatalytic efficiency in the degradation of rhodamine B and reactive orange dyes. The superoxide anion radical and hole were the important reactive species for dye degradation.     

Facile synthesis of copper tungstate (CuWO4) for novel photocatalytic degradation of tetracycline under visible light

In this study, CuWO₄ materials were synthesized via facile hydrothermal and heat treatment. The physicochemical properties of the synthesized materials were well analyzed by advanced characterization methods such as SEM, XRD, FT-IR and UV–Vis. Photocatalytic performance of these synthesized CuWO₄ materials were investigated via degradation of tetracycline (TC) under excitation of visible light, which was generated from a 32 W compact lamp. The material calcined at 500 °C contained only triclinic CuWO₄ phase. At low calcination temperature lower than 500 °C, WO₃ and CuWO₄·2H₂O remained in the synthesized materials while CuO and Cu₂O newly occurred when the material was calcined at 600 °C. The occurrence of impurities phases significantly decreased photocatalytic activity of the synthesized material. The synthesized CuWO₄-500, which was calcined at 500 °C, exhibited high visible light absorption capacity with band-gap energy (E_g) of approximately 2.13 eV. The CuWO₄-500 sample also exhibited great photocatalytic ability for decomposition of TC even under excitation of provided visible light. The study also investigated that pH 6 was optimal pH for TC degradation by the synthesized CuWO₄. Under optimized pH (pH 6), the synthesized CuWO₄ photocatalytically degraded over 60% TC after 2 h being irradiated by visible light.     

微波促进(R)-萘普生消旋反应

用微波辐射技术,以葡甲胺为催化剂、水为溶剂,于800W功率下回流反应100min,成功对(R)-萘普生进行消 旋,收率为95％.方法操作简单,反应时间短,后处理简便.     

Nanocrystalline TiO2 doped by small amount of pre-synthesized colloidal CdS nanoparticles for photocatalytic degradation of 1,2,4-trichlorobenzene

The chemical stability and hydrophobic nature of chloroarenes make them a persistent environmental hazard. Modeling of 1,2,4-trichlorobenzene (1,2,4-TCB) degradation in alcohol-water solution under UV irradiation was carried out with the aim of probing how the 1,2,4-TCB might behave in the environment. The photocatalytic activity of both bare TiO₂ and TiO₂ doped by colloidal CdS nanoparticles synthesized by the sol-gel method has been investigated in the processes of 1,2,4-TCB photodegradation in the aqueous protic solvent. Non-sensitized TiO₂ cannot be regarded as catalyst for the 1,2,4-TCB photodecomposition. On the contrary, the CdS/TiO₂ composite accelerated the 1,2,4-TCB photodegradation process. The concentration of CdS/TiO₂ was shown to effect on the 1,2,4-TCB photolysis mechanisms, which resulted in the quantitative ratios of the 1,2,4-TCB photolysis products.     

Chemical Stability of Ethyl Icosapentate Against Autoxidation. II. Effect of Photoirradiation on Oxidation Kinetics

The effect of ultraviolet (UV) or visible light (VIS) irradiation on the chemical stability of ethyl icosapentate [ethyl-(all-cis)-5,8,l l,14,17-icosapentaenoate] (EPA) was investigated at 45°C by means of HPLC and by measuring the peroxide value (POV). EPA was oxidized to peroxides after an induction period by photoirradiation, and the peroxide subsequently degraded to secondary products. The autoxidation of EPA followed consecutive reaction kinetics including an induction period, and the kinetic parameters of the oxidation were calculated based upon the consecutive reaction model by computer curve fitting. The results of the degradation rate constant, k, and the induction period obtained by HPLC showed that the radical and the peroxide formation rates are affected by UV, but not by VIS light irradiation. The formation rate constant of peroxide, kl, and its degradation rate constant to secondary products, k2, obtained from the POV under UV light irradiation, increased with irradiation intensity, during which the induction period decreased. On the other hand, kl, k2 and the induction period by VIS light irradiation did not change significantly. The relationship between the induction periods obtained by HPLC and POV and the UV light irradiation energy were superimposed in the plots, indicating that these parameters depended on the UV irradiation energy. The relationship between kl/k2 ratio and the UV irradiation energy suggested that the formation of secondary products was more remarkably accelerated by UV energy than that of peroxide.     

Stability of metronidazole, tetracycline HCl and famotidine alone and in combination

Metronidazole, tetracycline HCl and famotidine are commonly used for the treatment of Helicobacter pylori-associated peptic ulcer. In this paper, stabilities of these drugs and their combinations in solid and liquid states were studied as part of preformulation in the development of a combination drug delivery system. Solubility studies of metronidazole and tetracycline HCl were investigated, which indicated that both metronidazole and tetracycline HCl have high solubilities at and around pH 2.0. Metronidazole is relatively stable with little degradation in liquid phase. Tetracycline HCl in the dry state is stable when stored at room temperature regardless of exposure to light or humidity in the range of 20–65%. Enhanced temperature associated humidity effect was responsible for the instabilities of tetracycline HCl and famotidine to different extents. Elevated temperature accelerated the degradation of all the drugs in liquid phase but light exposure was not a factor for the degradation. The degradation processes of tetracycline HCl and famotidine were highly dependent on the pH of the solution, and relatively stable profiles were achieved at pH 4.0. No potential incompatibility between the drugs under storage conditions was observed in the development of a new multi-drug delivery tablet.     

Hypocrellin B-encapsulated nanoparticle-mediated rev-caspase-3 gene transfection and photodynamic therapy on tumor cells

Gene therapy and photodynamic therapy are two kinds of important therapeutic strategies for treating malignant tumors. In order to explore the combined effects of gene therapy and PDT on tumor cells, rev-caspase-3 gene was transfected into the tumor model CNE2 cells using hypocrellin B-encapsulated nanoparticle (nano-HB) as a carrier. The transfected CNE2 cells were then irradiated by light from a LED source and the survival rate was investigated 18 h after PDT. Apoptosis was analyzed by a flow cytometer with propidium iodine (PI) staining and the active caspase-3 expression was measured using flow cytometry with phycoerythrin (PE)-conjugated anti-active caspase-3 antibody. The result from the flow cytometer showed that the level of the activated caspase-3 significantly increased up to 63.10% in the transfected CNE2 cells. The survival rate 18 h after gene transfection alone and nano-HB-mediated PDT was 96.6±2.07%, 72.6±4.15%, respectively. However, the survival rate of the transfected CNE2 cells 18 h after LED exposure significantly decreased to 50.6±5.98% under the light energy of 4 J/cm(2). Apoptotic rate 18 h after the combination of gene transfection and PDT increased up to 24.65%. Our findings demonstrated that nano-HB could significantly enhance the transfection efficiency of rev-caspase-3 gene in the CNE2 cells. LED irradiation could effectively kill the treated CNE2 cells and induce apoptosis, suggesting hypocrellin B-encapsulated nanoparticle as an efficient gene carrier and a novel photosensitizer. The combination of gene therapy and PDT using nanoparticle as a mediator can be developed for treating nasopharyngeal carcinoma.     

Stability of microcystins from cyanobacteria—II. Effect of UV light on decomposition and isomerization

Microcystins are very potent hepatotoxins and strong liver tumor promoters produced by cyanobacteria, and their occurrence has been reported all over the world. They could threaten human health when toxic Microcystis occurs in water supply reservoirs. In this study, we examined the stability of microcystins during photolysis with UV light. The toxins were easily decomposed by UV light at wavelengths around the absorption maxima of the toxins and the decomposition depended on the intensity of the light. The half-life of microcystin LR by 147 μW/cm² UV irradiation was 10 min, and the toxin was completely decomposed by 2550 μW/cm² UV after 10 min. When the toxins were irradiated with weaker UV light, isomerization was also observed by a different mechanism from that during photolysis by sunlight and pigment, and several products including three geometrical isomers of the conjugated diene of Adda were detected. Microcystin RR showed almost the same behavior as that of microcystin LR under the same conditions. Since no noxious products were formed in the present study, a water treatment including UV irradiation is very possible for removing microcystins from raw water.     

吲哚菁绿光热治疗耐甲氧西林葡萄球菌感染的研究

目的　探讨吲哚菁绿（ICG）的光热治疗（PTT）性能及对耐甲氧西林葡萄球菌的杀灭效果。方法　利用紫外和荧光光谱对ICG的光物理性质进行表征;测定不同质量浓度ICG（0、12.5、25、50、100和200 mg/L）的光热升温曲线,评估ICG的光热转化性能;取小鼠乳腺癌4T1细胞与不同质量浓度的ICG溶液（0、50、100、200和500 mg/L）混合,通过MTT实验检测ICG的细胞毒性;取1×1010 CFU/mL的耐甲氧西林的金黄色葡萄球菌加入到96孔板中,将实验分为7组：PBS组、ICG组（500 mg/L）、激光照射组（1.5 W/cm2的808 nm激光照射10 min）、ICG+0.33 W/cm2激光照射组、ICG+0.66 W/cm2激光照射组、ICG+1 W/cm2激光照射组、ICG+1.5 W/cm2激光照射组,观察并记录存活的菌落数,分析基于ICG的PTT杀菌效果。结果　紫外吸收光谱证实ICG在808 nm处具有较强的光吸收能力;ICG溶液（质量浓度为200 mg/L）经功率密度为1.5 W/cm2的808 nm近红外激光照射10 min后,温度可升高23.3 ℃,而纯水的温度仅升高了4.8 ℃。ICG不同质量浓度组即50、100、200、500 mg/L组的细胞生存率分别为81.87%±2.69%、81.47%±2.94%、82.92%±2.61%、80.44%±2.98%,组间差异无统计学意义（F=0.402,P＞0.05）。不同功率密度激光照射组即0.33、0.66、1、1.5 W/cm2组的细胞生存率分别为97.21%±1.59%、94.92%±1.98%、93.89%±1.38%、93.03%±2.31%,组间差异无统计学意义（F=2.864,P＞0.05）。杀菌实验中,与PBS组比较,ICG+激光照射组随着激光功率密度的升高,细菌存活数量逐渐下降,差异有统计学意义（F=133.800,P＜0.01）。结论　ICG具有良好的生物相容性和光热治疗性能,在近红外激光照射下对耐甲氧西林葡萄球菌具有较强的杀灭效果,具有较好的临床转化应用价值。