光动力作用促人肝癌细胞HepG2凋亡及对bax，bcl-2蛋白表达的影响

应用流式细胞仪分析光动力作用后细胞凋亡及免疫组化染色检测凋亡相关蛋白bcl-2蛋白，bax蛋白表达水平．发现血卟啉光动力实验组人肝癌细胞HepG2凋亡率达24．23±1．86％，与对照组相比，差异非常显著（P〈0．01）；光动力作用后凋亡相关蛋白bcl-2表达显著高于对照组（P〈0．05）；实验结果显示血卟啉光动力作用具有诱导人肝癌细胞HepG2凋亡的生物学效应，而凋亡调控蛋白bcl-2表达水平的降低可能是血叶林光动力作用诱导人肝癌细胞HepG2凋亡的一个重要机制．     

光敏剂对肿瘤细胞损伤效应与孵育时间关系的拉曼光谱分析

利用拉曼光谱研究光敏剂与HepG2肝癌细胞不同孵育时间的光动力损伤效应。结果表明孵育时间与光动力损伤效应成正相关性,但孵育时间超过一定值,延长孵育时间并不能提高光动力损伤效应。     

新型光敏剂叶绿酸f对人膀胱癌T24细胞的光动力杀伤作用

将自主研发的新型光敏剂叶绿酸f与T24细胞共同孵育后,以650nm激光照射,通过MTT法检测光动力处理后T24细胞的生长抑制率,流式细胞术检测凋亡情况,同时利用激光共聚焦显微镜488nm和405nm双波长激发,应用线粒体探针,进行叶绿酸f的亚细胞定位。结果显示叶绿酸f为浓度2.5,5,10μg/mL对T24细胞生长抑制率在光能量密度4J/cm2下为17.68%,49.35%和84.42%,在1J/cm2时为4.34%,37.42%和78.38%;流式细胞术显示T24细胞光动力处理后,凋亡率为(45.23±1.2)%,显著高于对照组;激光共聚焦显微镜显示504nm激发叶绿酸f发出的红光与488nm激发线粒体探针产生的绿光分布基本一致。实验证明叶绿酸f对T24细胞杀伤效果明显,主要是通过作用于线粒体,诱导细胞凋亡来完成的。     

光动力疗法中光动力剂量的数学仿真研究

通过建立光动力治疗过程中激光、光敏剂、氧及其相互作用关系的数学模型,对组织中光动力剂量进行了模拟,研究了光动力剂量在组织内部分布变化的规律。模拟了激光剂量为50mW/cm2、100mW/cm2、150mW/cm2,光敏剂质量浓度为10mg/kg、20mg/kg、40mg/kg时光动力剂量变化。研究发现光动力剂量在组织内分布是非线性的,大小受激光强度、光敏剂剂量、氧浓度和组织光学参数等因素的影响,且光敏剂浓度的变化对光动力剂量变化的影响尤为明显。     

新光敏剂铝酞菁与人癌细胞作用的荧光研究

本文对用于光动力癌症疗法(PPT)的新光敏剂铝酞菁(AlSPC)与人癌细胞的作用进行了实验探讨。细胞荧光光谱的测定及荧光强度的定量表明,铝酞菁能被人癌细胞所吸收,且经40μg/mlAlSPC培育24小时后,细胞对AlSPC吸收的量级为3.47μg/107细胞。对人癌细胞的光敏杀伤显示,杀伤效果正比于光敏剂培育浓度与光辐照剂量。由脂质过氧化的荧光研究表明,经光敏反应后人癌细胞膜的脂质过氧化代谢产物丙二醛(MDA)明显增高,揭示在AlSPC光敏反应中有活性氧作用。色氨酸降解的荧光实验证实,在光敏反应中有单线态氧(1O2)的生成。     

Au@TiO_2纳米核壳与HMME结合体的制备及其光动力疗效初探

光动力疗法(PDT)是一种高效、安全、微创的新型治疗方法,国产光敏剂血卟啉单甲醚(HMME)介导的光动力疗法由于其成分单一、单态氧产量高及光敏周期短,临床上已用于脑胶质瘤和鲜红斑痣的治疗。为了进一步提高光动力疗效,本研究基于晶种生长法制备稳定粒径均一的吸收峰在530nm的阳离子金纳米球。采用毒性低且阴离子电解活化作用强的聚(四-苯乙烯磺酸钠)(PSS)进行修饰。利用静电吸引力将钛源TiCl_3水解的TiOH~(2+)与其结合并氧化制备AuNP@TiO_2核壳,通过改变NaHCO_3量制得不同TiO_2壳层厚度的AuNP@TiO_2核壳,并进一步将其与HMME结合制备结合体。采用紫外-可见吸收光谱、红外光谱、激光纳米粒度仪和透射电镜对所制样品进行表征。结果表明新型的光敏剂粒径均匀,结构稳定。最后采用细胞实验验证了其光动力疗效。总之,该研究合成了新型的Au@TiO_2-HMME纳米光敏剂,通过人口腔表皮样癌细胞系KB细胞与新型核壳纳米结构的光动力作用,与纯HMME相比,在最优条件下可提高约35%的细胞杀伤率。     

关于PDT光敏剂敏化效应光谱及其量子产率的研究

从实验的角度研究了HA光敏剂激发态的敏化特性,建立了单态氧量子产率在近红外区的荧光光谱测量系统,测定了HA光敏剂的单态氧量子产率为0．78。结果表明,该类光敏剂具有较强的敏化效应,是一类有前途的光动力治疗(PDT)候选光敏剂。     

激光医学

R318.51 2004064139 光动力治疗中光的有效吸收光剂量及其确定=Effective absorbed light dose in photodynamic therapy and its measurement[刊,中]/王颖(解放军总医院激光科.北京(100853)),刘凡光…∥激光生物学报.—2004,13(2).—91-96 光动力治疗中真正有效的光剂量是达到病变组织并且被组织中的光敏剂所吸收的那部分剂量,即有效吸收光剂量。明确组织中的有效吸收光剂量可以指导临床治疗,从而避免治疗剂量不足(治疗不彻底)或剂量过量(造成正常组织的热损伤)。而确定PDT中光的有效吸收剂量时,需测定组织中考察点的光辐射能流率。在目前计算和模拟组织中光辐射能流率的方法中,都需要首先确     

灵芝酸A对人肝癌细胞的辐射增敏效应的初步研究

本研究旨在初步探讨灵芝酸A(GAA)对人肝癌细胞系HepG2在高LET中子和低LET的γ射线条件下的辐射敏感性的影响及差异。研究中,我们用CCK-8方法检测不同浓度GAA对HepG2增殖抑制作用。选取低浓度(5μmol/L)GAA预处理细胞24 h,分别给予不同剂量的中子辐照或γ射线辐照,分别检测克隆存活率、细胞凋亡和γH2AX蛋白的foci的形成。结果表明:在不加GAA的情况下,高LET中子辐射比低LET的γ射线对细胞产生的凋亡比例高;在添加了GAA后,与未加GAA对照组相比,诱导细胞凋亡的比例明显增加;另外,加GAA处理后,细胞增殖抑制率也随着辐照剂量的增加而增高。即GAA能增加HepG2细胞的辐射敏感性,而在同样GAA剂量下,HepG2细胞对高LET中子辐射比低LET的γ射线更敏感。由此,这项研究说明灵芝酸或可开发成为一种天然辐射增敏剂,从而为癌症特别是肝癌的放疗提供新的辅助治疗方法。     

超声激活血卟啉对B16小鼠黑色素瘤细胞杀伤作用的研究初报

采用MTT法检测,经超声、超声 血卟啉分别作用后细胞线粒体内琥珀酸脱氢酶的活性,研究超声激活血卟啉对体外培养的B16小鼠黑色素瘤细胞的杀伤作用。结果表明:1.6MHz超声对B16小鼠黑色素瘤细胞辐照5min可表现出明显的杀伤效应,而超声协同被激活的血卟啉对B16细胞的杀伤作用比单纯超声的杀伤效应更加明显,且有显著性差异。     

Self-organization of five species in a cyclic competition game

Cyclic competition game models, particularly the “rock–paper–scissors” model, play important roles in exploring the problem of multi-species coexistence in spatially ecological systems. We propose an extended “rock–paper–scissors” game to model cyclic interactions among five species, and find that two of the five can coexistent when biodiversity disappears, which is different from the “rock–paper–scissors” game. As the number of fingers is five, we named the new model the “fingers” game, where the thumb, forefinger, middle finger, ring finger, and little finger cyclically dominate their subsequent species and are dominated by their former species. We investigate the “fingers” model in two ways: direct simulations and nonlinear partial differential equations. An important finding is that the number of species in a cyclic competition game has an influence on the emergence of biodiversity. To be specific, the “rock–paper–scissors” model is in favor of maintaining biodiversity in comparison with the “fingers” model when the variables (population size, reproduction rate, selection rate, and migration rate) are the same. It is also shown that the mobility and reproduction rate can promote or jeopardize biodiversity.     

Contrastive analysis on tone between Putonghua and Taiwan Mandarin

The differences of the pitch and duration of Chinese syllables between Putonghua （PTH） and Taiwan Mandarin （TM） were studied. The speech materials to be used are not only isolated syllables, but also sentences. The results reveal that： For the isolated syllables, T1 and T2 in TM are influenced by Minnan dialect, therefore their pitch are lower than those in PTH. T3 is fall-rise in PTH, while it is fall in TM. Moreover, the syllable duration sequence for different tone is T3〉T2〉T1〉T4 in PTH, while it is T1〉T2〉T3〉T4 in TM. For the syllables in sentences, T2 is mid-rise in PTH, while it is mid-level in TM. And the T3 is longer than T4 but shorter than T1 or T2 in PTH, while it is the shortest in TM. Furthermore the effects of prosodic phrase boundary on duration for different tones are almost the same in PTH, but the lengthening part of T1 or T2 is longer than that of T3 or T4 in TM.     

Experimental study on downstep in Chinese intonation

Downstep in pitch contour of Chinese Putonghua is examined using subtly designed sentences by controlling tone combinations. The results show both automatic and nonautomatic downstep phenomena exist in Chinese. In non-automatic downstep, low tones compress downwards the pitch range of the following syllables. and the main influence of downstep is on topline. Low tone not only lower the topline behind it, but also raise the high tones before it, the effects are compatible with each other. In automatic downstep, the topline of pitch contour in intonational phrase is presented as a linear downtrend, but it differs among speakers due to the effect of personal stress practice. In comparison with downstep phenomenon in other tone or non-tone languages, the downstep ratio in Chinese is not constant, and the domain of downstep is not limited within the adjacent tones.     

Abelian-Higgs phase of SU(2) QCD and glueball energy

It is shown that SU(2) QCD admits an dual Abelian-Higgs phase, with a Higgs vacuum of a type-Ⅱ superconductor. This is done by using a connection decomposition for the gluon field and the random-direction approximation. Using a bag picture with soft wall, we presented a calculational procedure for the glueball energy based on the recent proof for wall-vortices [Nucl. Phys. B 741(2006)1].     

Theoretical analysis and simulation of conjugate heights for dual-conjugate AO system in lidar

A multi-conjugate adaptive optics （MCAO） can offer a possibility of widening field of view （FOV） characterized by the isoplanatic angle, and the choose of conjugate height becomes a basic problem for MCAO, which influences the size of iosplanatic angle. Considering the application of lidar, the isoplanatic angle＇s expressions of two deformable mirrors （DMs） MCAO for uplink and downlink are deduced. The effects of conjugate heights for dual-conjugate AO are thoughtfully discussed, and the isoplanatic angles are further analyzed. The results show that the isopanatic angle varies with the conjugate height and reaches the maximum as the conjugate height is at the optimal altitude. Moreover, the optimal conjugate height changes with the propagation distance.     

Quick single-photon detector with many avalanche photo diodes working on the time division

Due to the limit of response speed of the present single-photon detector, the code rate is still too low to come into practical use for the present quantum key distribution (QKD) system.A new idea is put up to design a quick single-photon detector.This quick single-photon detector is composed of a multi-port optic-fiber splitter and many avalanche photo diodes (APDs).Au of the ports with APDs work on the time division and cooperate with a logic discriminating and deciding unit driven by the clock signal.The operation frequency lies on the number N of ports, and can reach N times of the conventional single-photon detector.The single-photon prompt detection can come true for high repetition-rate pulses.The applying of this detector will largely raise the code rate of the QKD, and boost the commercial use.     

Signal generation in an isotropic medium in scanning electron acoustic microscope

Based on the research in Ref. [5][Materials Science and Engineering, 1989; A122： 57 63], an improved model of heat source is set up, the different modes of Lamb wave in an isotropic sample generated by a chopped electron beam at frequency f are obtained with integral transform and normal function expansion method, and the output signal of PZT coupled at the back surface of the sample is found out. The generation mechanism of SEAM （Scanning Electron Acoustic Microscopy） signal is discussed. It shows that the SEAM is a near field imaging technique with high spatial resolution and its best lateral spatial resolution is about 2√2α （α is the radius of the focused electron beam）. Some of experimental results of SEAM images are presented in the paper and it shows that the spatial resolution of SEAM is better than 0.5 μm and smaller than the thermal diffusion length of the sample. Therefore the character of near field imaging in SEAM is also proved experimentally.     

High efficiency filtering using two-dimensional photonic crystal coupled cavity structures

Transmission spectra of coupled cavity structures (CCSs) in two-dimensional (2D) photonic crystals (PCs) are investigated using a coupled mode theory, and an optical filter based on CCS is proposed. The performance of the filter is investigated using finite-difference time-domain (FDTD) method, and the results show that within a very short coupling distance of about 3λ, where λ is the wavelength of signal in vacuum, the incident signals with different frequencies are separated into different channels with a contrast ratio of 20 dB. The advantages of this kind of filter are small size and easily tunable operation frequencies.