光化学反应在分析化学中应用的研究——光动力学法测定痕量铬

在H_2SO_4—H_2C_2O_4介质中,光照甲基红溶液,铬(Ⅵ)离子能催化这个褪色反应.实验结果表明,甲基红溶液的褪色速度同铬(Ⅵ)浓度呈良好的线性关系.本工作选择了合适的试验条件,研究了外来离子的干扰,并用环境样品考查了方法的精密度和准确度.方法的最低检出限为0.05ug/ml,铬(Ⅵ)浓度在0.1～1.4ug/ml范围内符合比尔定律.

光动力学法测定高纯金属铯中的痕量铁

本文用光动力学法测定了高纯金属铯中的采量铁，其线性范围为 ０— ５０μｇ／５０ｍｌ服从比耳定律，标准加入回收率在９５—１０４％，其分析结果与萃取－原子吸收分光光度法测定结果相吻合，其准确度和精密度能满足要求．

基于共价有机框架的仿生光动力学治疗试剂的构建

共价有机框架(COF)是一类新兴的多孔有机聚合物,因其具有较大的比表面积、有序的孔道结构以及良好的生物相容性,已成为具有潜力的纳米药物载体.制备了基于COF纳米颗粒的仿生纳米复合物,负载光敏剂孟加拉玫瑰红(RB),并包裹癌细胞膜(CMV)对该复合物进行仿生修饰.结果表明:制备的COF/RB@CMV纳米复合物具有良好的生物兼容性,能够被肿瘤细胞有效摄取,并在光照激活条件下产生对细胞具有高毒性的活性氧化物(ROS),进而起到了杀伤肿瘤细胞的作用.提出了一种新的基于COF的仿生纳米平台用作光动力学治疗(PDT)试剂.

激光医学应用最新进展及前沿

介绍了激光的特点及其对生物组织的作用机理,叙述了激光在医学上应用的最新进展和前沿。重点评述了激光在心血管、肿瘤、眼科、皮肤科和中医之中的最新研究和应用前沿。为了解激光医学的应用进展提供参考。

5-aminolaevulinic Acid-photodynamic Therapy for the Treatment of Cervical Condylomata Acuminata

Objective To investigate the efficacy and safety of photodynamic therapy （PDT） with topical 5-aminolaevulinic acid （ALA） on cervical condylomata acuminata. Methods Patients with cervical condylomata （n=30） were allocated into primary and recurrent group, and were given topical ALA under occlusive dressing for 3 hours followed by irradiation with semiconductor laser at a dose of 100 Jcm 2 and a power of 100 roW. The treatment was repeated 7 days later if the lesion was not completely removed after the first treatment. Complete response rate and recurrence rate of wart lesions as well as rate of adverse reaction were analyzed. Results The total complete response rate of PDT was 100% and the total recurrence rate was 5% after 3 months of follow-up. Recurrence rate of recurrent group was significantly lower than that of prior managements （100%, P〈0.01）. The side effects of PDT in patients mainly included mild burning and/or stinging restricted to the illuminated areas, and was significant lower than their own control （25% vs. 100%, P〈0.05）. Conclusion Compared with conventional therapies, topical application of ALA-PDT is a simple, effective, safe, well-tolerated, and low recurrence rate treatment for cervical condylomata acuminata.

Pharmacokinetics and Biodegradation of Chitosan in Rats

Chitosan, an excellent biomedical material, has received a widespread in vivo application. In contrast, its metabolism and distribution once being implanted were less documented. In this study, the pharmacokinetics and biodegradation of fluorescein isothiocyanate(FITC) labeled and muscle implantation administrated chitosan in rats were investigated with fluorescence spectrophotometry, histological assay and gel chromatography. After implantation, chitosan was degraded gradually during its distribution to diverse organs. Among the tested organs, liver and kidney were found to be the first two highest in chitosan content, which was followed by heart, brain and spleen. Urinary excretion was believed to be the major pathway of chitosan elimination, yet 80% of chitosan administered to rats was not trackable in their urine. This indicated that the majority of chitosan was degraded in tissues. In average, the molecular weight of the degradation products of chitosan in diverse organs and urine was found to be <65 k Da. This further confirmed the in vivo degradation of chitosan. Our findings provided new evidences for the intensive and safe application of chitosan as a biomedical material.

Measurement of Trace Manganese(Ⅱ) by the Catalytic Kinetic Spectrophotometric Method

A new kinetic spectrophotometric method is developed for the measurement of manganese(Ⅱ) in water. The method is based on the catalytic effect of manganese(Ⅱ) with the oxidation of weak acid brilliant blue dye(RAWL) by KIO4 using the Nitrilo triacetic acid(NTA) as an activation reagent. The optimum conditions obtained are 40 mgL-1 RAWL,1×10-4molL-1 KIO4,2×10-4 molL-1 Nitrilo triacetic acid(NTA),pH = 5.8,the reaction time of 3.00 min and the temperature of 20.0 ℃. Under the optimum conditions,the proposed method allows the measurement of manganese(Ⅱ) in a range of 0-50.0 ng mL-1 and with a detection limit of down to 0.158 ng mL-1. The recovery efficiency in measuring the standard manganese(Ⅱ) solution is in a range of 98.5%-102%,and the RSD is in a range of 0.76%-1.25%. The new method has been successfully applied to the measurement of manganese(Ⅱ) in both fresh water and seawater samples with satisfying results. Moreover,few cations and anions interfere with the measurement of manganese(Ⅱ). Compared with other kinetic catalytic methods and instrumental methods,the proposed method shows fairly good selectivity and sensitivity,low cost,cheapness,low detection limit and rapidity. It can be applied on boats easily.

Photo oxidation of DBT using carbon nanotube titania composite as visible light active photo catalyst

Sulfur removal from liquid fuels has increased in importance in recent years. Although hydrodesulfurization is the usual method for removing sulfur, the elimination of thiophene compounds using this process is difficult. Photocatalysis is an alternative method being developed for thiophene removal at ambient conditions. Among semiconductors, titania has shown good potential as a photo-catalyst; however, quick recombination of electron holes hinders its commercial use. One way to decrease the recombination rate is to combine carbon nanotubes with a semiconductor. In this work, multiwall carbon nanotube （MWCNT） / titania composites were prepared with different mass ratios of MWCNT to titania using tetraethyl orthotitanate （TEOT） and titanium tetra isopropoxide （TTIP） as precursors of titania. Dibenzothiophene （DBT） photocatalytic removal from n-hexane was measured in both the presence and absence of oxygen. The results indicated that the best removal occurred when the MWCNT to titania ratio was 1. When the ratio exceeded this number, DBT removal efficiency decreased due to light scattering. Also, the composites prepared by TEOT exhibited better efficiency in DBT removal. The research findings suggested that the obtained composite was a visible light active photocatalyst and exhibited better performance in the presence of oxygen. Kinetics of photocatalytic DBT removal was a first-order reaction with removal rate constant 0.7 h–1 obtained at optimum conditions.

Exact Solution for Phenomenon of atomic Collapse and Revival under Rotating Wave and Anti-Rotating Wave Approximation

An accurate method to solve the daynes Cummings （J-C） Hamiltonian has been investigated here. The phenomenon of atomic collapse and revival predicted by Jaynes-Cummings model is demonstrated. Solutions are consis- tent with the precious such as using the operator method. Furthermore, the Jaynes-Cummings Hamiltonian including the anti-rotating term is also solved precisely using this accurate way so that results agree with experiments better. Essences of the anti-rotating term are revealed. We discuss the relations of the phenomenon of atomic collapse and revival with the average photons number, the light field phase angle, the resonant frequency, and the size of coupling constant. The discussions may make one select suitable conditions to carry out experiment well and study the virtual light field effect on cavity quantum electrodynamics.

Dynamic tracking and mobility analysis of single GLUT4 storage vesicle in live 3T3-L1 cells

Glucose transporter 4 (GLUT4) is responsible for insulin-stimulated glucose transporting into the insulin-sensitive fat and muscle cells. The dynamics of GLUT4 storage vesicles (GSVs) remains to be explored and it is unclear how GSVs are arranged based on their mobility. We examined this issue in 3T3-L1 cells via investigating the three-dimensional mobility of single GSV labeled with EGFP-fused GLUT4. A thin layer of cytosol right adjacent to the plasma membrane was illuminated and successively imaged at 5 Hz under a total internal reflection fluorescence microscope with a penetration depth of 136 nm. Employing single particle tracking, the three-dimensional subpixel displacement of single GSV was tracked at a spatial precision of 22 nm. Both the mean square displacement and the diffusion coefficient were calculated for each vesicle. Tracking results revealed that vesicles moved as if restricted within a cage that has a mean radius of 160 nm, suggesting the presence of some intracellular tethering matrix. By constructing the histogram of the diffusion coefficients of GSVs, we observed a smooth distribution instead of the existence of distinct groups. The result indicates that GSVs are dynamically retained in a continuous and wide range of mobility rather than into separate classes.

Clinical Application of Photodynamic Therapy

Photodynamic therapy（PDT） is a new medical technology, the study on photodynamic therapy was in full swing in the past two decade. Scientists have made great progress in it. Photosensitizer,oxygen and light source play important role in photodynamic therapy. PDT is a light activated chemotherapy. A photon is adsorbed by a photosensitizer which moves the drug into an excited state. The excited drug can then pass its energy to oxygen to create a chemical radical called “singlet oxygen”. Singlet oxygen attacks cellular structures by oxidation. Such oxidative damage might be oxidation of cell membranes or proteins. When the accumulation of oxidative damage exceeds a threshold level,the cell begins to die. Photodynamic therapy allows selective treatment of localized cancer. PDT involves administration of a photosensitizer to the patients, followed by delivery of light to the cancerous region. The light activates the agent which kills the cancer cells. Without light,the agent is harmless. As a new therapy,photodynamic Therapy has great Advantage in treating cancers. 1. PDT avoids systemic treatment. The treatment occurs only where light is delivered, hence the patient does not undergo go needless systemic treatment when treating localized disease. Side-effects are avoided, from losing hair or suffering nausea to more serious complications. 2. PDT is selective. The photosensitizing agent will selectively accumulate in cancer cells and not in surrounding normal tissues. Hence ,there is selective targeting of the cancer and sparing of surrounding tissues. 3. when surgery is not possible. PDT kills cancer cells but does not damage collagenous tissue structures,and normal cells will repopulate these structures. Hence,if a patient has cancer in a structure that cannot be removed surgicaily（eg. ,the upper bronchi of the lung） ,PDT can still treat the site. 4. PDT is repeatable. Uniike radiation therapy,PDT can be used again and again. Hence,it offers a means of longterm management of cancer even if complete cure is not attainable.

Determination of Clarithromycin in Human Plasma by Liquid Chromatography-Tandem Mass Spectrometry： Validation and Application in Clinical Pharmacokinetic Study

Aim To develop a liquid chromatographic-tandem mass spectrometric (LC-MS-MS)method to determine clarithromycin in human plasma. Methods The analyte and internal standardroxithromycin were extracted from plasma samples by n-nexane-dichloromethane-isopropanol(300:150:15, V/V/V) and chromalographed on a C_(18) column. The mobile phase consisted ofmethanol-water-formic acid (80 = 20:1, V/V/V) . Detection was performed on a triple quadrupoletandem mass spectrometer via electrospray ionization source (ESI) in the positive mode. Results Themethod had a lower limit of quantification of 10.0 ng·mL^(-1) when 0.2 mL plasma was used. Thelinear calibration curves were obtained in the concentration range of 10.0 - 5000 ng·mL^(-1) . Theintra- and inter-run precisions were lower than 3.3% in terms of relative standard deviation (RSD),and the accuracy ranged +- 0.7% in terms of relative error (RE). T_(max), C_(max), T_(1/2) andAUC_(0-24h), values were found to be (3.1 +- 2.7)h, (8 750+-4734) ng·mL^(-1), (5.3+-2.2) h, and(5932+-2449)ng·mL^(-1), respectively, after a single oral dose of 250 mg clarithromycin tablet to18 volunteers. Conclusion This validated method was successful in the evaluation of phaimacokineticprofiles of clarithromycin tablets administered to 18 healthy male volunteers.

Using Ion-velocity Map Imaging Technique to Study Photodissociation of 2-Bromopentane

The photodissociation dynamics of 2-bromopentane at -234 nm has been investigated by utilizing ion-velocity map imaging technique. The mapped images of Br（2P3/2） （denoted as Br） and Br（2p1/2） （denoted as Br＊） fragments were analyzed by means of the speed and angular distributions, respectively. The speed distributions can be fitted with two Gaussian components which are correlated to the two independent reaction paths on the excited po- tential energy surfaces （PES）. The high-energy component is from the prompt dissociation along the C-Br stretching mode, while the low-energy one is related to the dissociation from the coupling of the C-Br stretching and bending modes. Relative quantum yield is measured to be 0.892 for Br in the photodissociation of 2-bromopentane at 234 nm. Combining the anisotropy parameter with the relative quantum yield of Br and Br fragments, the contributions of the excited 3Q0, 3Q1, and 1Q1 states to the products Br and Br were derived. The effect of alkyl branching on the mechanism of photodissociation was discussed by comparing the photodissociation processes of four isomers of bromopentane.

Effect of a Novel Nucleating Agent on Isothermal Crystallization of Poly（L-lactic acid）

The effect of a novel active nucleating agent(TBC8-eb) on the isothermal crystallization of poly(L-lactic acid) (PLLA) was studied by differential scanning calorimetry(DSC) and Fourier transform infrared spectroscopy(FTIR) . The analysis on kinetics demonstrates that TBC8-eb can not only accelerate the crystallization rate but also transform most of the original spherulite crystals of PLLA into sheaf-like crystals. Furthermore,the free energy of folding(σe) of PLLA and PLLA with TBC8-eb is 0.15 and 0.06 J·m-2,respectively,which suggests that the addition of TBC8-eb favors the regular folding of molecule chains in the crystallization of PLLA,improv-ing its crystallization rate. The FTIR results show that TBC8-eb can accelerate the conformational ordering of PLLA in the isothermal crystallization. The conformational ordering of PLLA nucleated with TBC8-eb begins with the interchain interaction of CH3,and then a short helix emerges where a couple of CH3 groups interact.

Comparison of Improved Meshless Interpolation Schemes for SPH Method and Accuracy Analysis

In the smoothed particle hydrodynamics (SPH) method, a meshless interpolation scheme is needed for the unknown function in order to discretize the governing equation.A particle approximation method has so far been used for this purpose.Traditional particle interpolation (TPI) is simple and easy to do, but its low accuracy has become an obstacle to its wider application.This can be seen in the cases of particle disorder arrangements and derivative calculations.There are many different methods to improve accuracy, with the moving least square (MLS) method one of the most important meshless interpolation methods.Unfortunately, it requires complex matrix computing and so is quite time-consuming.The authors developed a simpler scheme, called higher-order particle interpolation (HPI).This scheme can get more accurate derivatives than the MLS method, and its function value and derivatives can be obtained simultaneously.Although this scheme was developed for the SPH method, it has been found useful for other meshless methods.

Study on the Determination of Trace Ni(II) by the Catalytic Kinetic Spectrophotometric Method

A new kinetic spectrophotometric method has been developed for the determination of trace Ni （Ⅱ in natural water. The method is based on the catalytic effect of Ni （Ⅱ） on the oxidation of weak acid brilliant blue dye （RAWL） by KIO4 in acid medium. The concentration of nickel （Ⅱ） can be determined spectrophotometrically by measuring the decrease of absorbance of RAWL at λ = 626 nm using the fix-time method. The influencing factors are investigated by the orthogonal experimental design. The obtained optimum analytical conditions are： pH = 2.00, CRAWL = 5.00×10^-5 mol·L^-1, c KlO4 = 2.00× 10^-5 mol·L^-1, the reaction time t= 10min and the temperature T = 25 ℃. Under the optimum conditions, the developed method allows the measurement of Ni （Ⅱ） in a range of 0 - 40.0ngmL1. The standard deviation of eleven independent measurements of blank reaction is S = 3.08× 10^-3 and the limit of detection is 2.20ng·mL^-1. The relative standard deviations （RSDs） in six replicate determinations of 5 ngmL-1 and 8 ngmL1 Ni （Ⅱ） are 2.87% and 1.11%, respectively. Moreover, the experiments show few cations and anions can interfere with the measurement of Ni （Ⅱ）. The recovery efficiencies of this method are in a range of 97.0%-102.5% in freshwater samples. But there is a decreasing effect, which is about 0.2 times the added Ni （Ⅱ） in seawater medium. After reasonable calibration this processing method is used for the determination of Ni （Ⅱ） in seawater samples successfully. The results show this developed method has high accuracy and precision, high sensitivity, large range of linearity and high speed. The method can, therefore, be employed at room temperature.

Determination of Trace Vanadium (Ⅴ) in Seawater and Fresh Water by the Catalytic Kinetic Spectrophotometric Method

A new kinetic spectrophotometric method has been developed for the determination of vanadium（V）.The method is based on the catalytic effect of vanadium（V）on the oxidation of weak acid brilliant blue dye（RAWL）by KBrO3 using the citric acid as activation reagent.The obtained optimum conditions are：c（RAWL）= 1×10-4 molL-1,c（KBrO3）= 3×10-2 molL-1,c（citric acid）=9×10-3 molL-1,pH = 2.50,the reaction time being 7.0min and the temperature being 25.0℃.Under the optimum conditions,the proposed method allows the determination of vanadium（V）in the range of 0-70.0ng mL-1 and the detection limit is down to 0.407 ng mL-1.For standard vanadium（V）solution determination,the recovery efficiency is in the range of 98.5%-102% and the RSD ranges from 0.76%-1.25%.Moreover,it is demonstrated that most cations and anions do not interfere with the determination of vanadium（V）under the analytical condition.The new method was successfully applied in the determination of vanadium（V）in fresh water and seawater samples with satisfactory results.Vanadium（V）in the seawater samples from Qingdao offshore was determined using the method and the distribution of vanadium（V）was mapped.Compared with other instrumental analytical methods,the proposed method shows good selectivity,sensitivity,simplicity,lower cost and rapidity.It can be employed on shipboard easily.

A Research on Particle-Based Parallel Methods for Fluid Animation

In this paper, we present an acceleration strategy for Smoothed Particle Hydrodynamics （SPH） on multi-GPU platform. For single-GPU, we first use a neighborhood search algorithm of compacting cell index combined with spatial domain characteristics For multi-GPU, we focus on the changing patterns of SPH＇s computational time. Simple dynamic load balancing algorithm works well because the computational time of each time step changes slowly compared to previous time step. By further optimizing dynamic load balancing algorithm and the communication strategy among GPUs, a nearly linear speedup is achieved in different scenarios with a scale of millions particles. The quality and efficiency of our methods are demonstrated using multiple scenes with different particle numbers.

Progress in femtochemistry and femtobiology

Femtoscience offers a unique way to understand the dynamics in physics, chemistry and biology. This subject focuses on the process happening at femto-to pico-second time scale by femtosecond optical methods. Widely used in chemistry it reveals chemical reactions, including bond breaking, forming, and stretching, which happens at an ultrafast time scale. Femtoscience is also important in the biological system, for example, light harvesting system and vision system. Femtoscience in physics is also widely used, but it is not studied in this paper. Instead, we report new advances in femtochemistry and femtobiology, including structural dynamics, coherent control, enzyme function dynamics and hydration in the protein system. We also introduce attosecond science, focusing on electron dynamics at an extreme short time scale.