声化学激活血卟啉对瘤细胞K562作用的研究

文章研究了超声激活血卟啉对人体肿瘤细胞K562的作用以及声辐照剂量和血卟啉浓度对瘤细胞杀伤率的影响。结果表明，声辐射剂量和血卟啉浓度和瘤细胞杀伤率呈正相关系。当频率为1．8MHz、声强度为1．5W／cm^2、作用时间为60s、血卟啉浓度为200μg／mL时，超声激活血卟啉对K562肿瘤作用效果较佳，杀伤率达98％，超声单独作用仅为42％，单纯血卟啉无抗肿瘤效应。     

声动力学疗法对人体肿瘤细胞K562的杀伤效应

本文研究了聚焦超声激活血卟啉对人体红白血瘤细胞Ｋ５６２的作用，通过大量实验归纳，当作用时间为１００ｓ，血卟啉浓度为２００μｇ／ｍｌ时，聚焦超声（频率１．４ＭＨｚ；强度１．０Ｗ／ｃｍ＾２）激活血卟啉对瘤细胞杀伤效果较佳，杀伤率达９８％，而单纯超声作用，杀伤率仅为５０％，单纯血卟啉对瘤细胞无杀伤作用，活性净化剂组氨酸瘤细胞样伤率有明显作用，而甘露醇则无影响，初步分析得到，单线态氧是杀死瘤细胞Ｋ５６２的     

动态聚焦超声换能器的研究与设计

介绍了为超声激活血卟啉抗肿瘤效应而研究的动态聚焦超声换能器。它是由６个等间距，等宽度的同心圆环和１个中心圆片组成的７元平面 能器阵。通过改变辐射孔径和每个阵元电激励信号的延迟时间，实现动态聚焦衣在各聚焦处声强度一致，导出了聚焦声场声压分布表达式，并设计出换能器的具体结构参数。     

超声激活血卟啉抗肿瘤疗法的研究现状

首先介绍了超声作用的物理机理和血卟啉及其衍生物的化学结构及物理化学性质,对超声激活血卟啉抗肿瘤疗法(声动力学疗法)近15年国内外的试验进展情况进行了总结,对比了不同参数超声系统对不同细胞系肿瘤的作用效果。重点探讨了超声激活血卟啉抑制肿瘤增殖的物理、化学和生物学机理,着重介绍了单线态氧机制和自由基理论,并对今后的基础研究和临床实践进行了展望。     

超声声化学激活血卟啉效应的研究

本文用 1,3 二苯基异苯并呋喃 (DPBF)检测了超声激活血卟啉的效率 ,并寻找了声参量与激活效率之间的关系。结果表明 ,在一定条件下 ,DPBF的相对消耗量随着辐照时间、声强度的增大而增大 ,超声频率及血卟啉浓度对DPBF相对消耗量也有影响。这一结果为声动力学疗法应用于临床具有重要的意义。     

利用声化学激活血卟啉抗肿瘤效应的研究

本文介绍了超声激活血卟啉抗肿瘤效应－声动力学疗法的国内外研究进展，总结了近几年来的研究方法及结果，声动力学疗法弥补了光动力学疗法的不足，具有较大的应用前景。     

双频超声破解污泥实验方法

使用20kHz和25kHz双频超声破解污泥装置,根据污泥滤液COD、NH3-N、TP的增量研究复频超声破解污泥的效果,并且详细探讨了影响复频超声破解污泥的影响因素（不同频率组合、不同作用方式、不同功率组合、不同时间组合）。实验结果表明双频超声更有利于污泥破解,为污泥破解方法的应用和今后进一步扩大其研究提供一定的基础。     

复合材料层压板分层缺陷相控阵超声检测参数优化方法EI北大核心CSCD

针对复合材料层压板分层缺陷的准确识别问题,通过仿真与实验提出相控阵超声检测激活孔径优化方法,研究并分析不同聚焦深度下激活孔径对声场特性和检测效果的影响。首先,针对相控阵超声接触式检测方法,推导出固固界面下的多点源三维声场模型;然后,对相控阵超声声场进行仿真,研究不同激活孔径下的声场特性;最后,采用热压工艺制备含分层缺陷的碳纤维增强树脂基复合材料(CFRP)层压板,并搭建相控阵超声检测系统对其进行检测。实验结果表明,通过对相控阵超声激活孔径进行优化选择,能够实现CFRP层压板分层缺陷的准确识别,有效提高缺陷检测精度。     

基于K-wave的经颅超声聚焦仿真研究

由于颅骨形状不规则，声速、密度等声学参数分布不均匀，使用传统相控聚焦的方法进行经颅超声精确聚焦时会出现焦点偏移、焦点形状畸变、散焦的现象，时间反转法被认为是能够克服颅骨非均匀特性，实现经颅聚焦的有效手段。而利用传统有限元，有限差分法进行数值仿真时，往往需要划分十分精密的网格进行计算，耗费大量的时间。K空间伪谱法通过在空间域上进行傅里叶变换，时间域上进行有限差分的方法求解声波方程，能够在降低计算网格密度的同时保证计算精度。为了克服颅骨对聚焦超声造成的焦移影响，同时避免声学模型计算量过大的问题，本文使用Matlab K-wave开源工具箱，对食蟹猴颅骨CT数据进行三维声学建模，实现了基于时间反转法的经颅超声聚焦，讨论了时间反转法对于颅骨不规则形状及非均匀声速造成的焦移的补偿。仿真结果表明，K-wave在提高计算速度的同时能够服务于精准经颅超声聚焦，且相较于传统基于声时差法的相控聚焦方法，时间反转法在预设焦点位置，焦点强度更高，焦斑形状更为规则，聚焦效果更好。     

双频超声空化效应强化提取中药有效成分的实验研究

设计了25kHz和40kHz的双频超声强化提取装置,以碘化钾中碘的释放量研究双频超声的空化效应,并以黄柏为原料研究双频超声对提取小檗碱的强化效果,结果表明:在相同实验条件下,双频超声的空化效应远大于单频超声的空化效应;25kHz与40kHz双频超声时的提取率为64.1%,单频25kHz及40kHz时的提取率分别为36.8%和19.0%,双频超声强化的提取率显著高于单频超声强化的提取率。研究还表明,双频超声强化可以降低提取温度,缩短提取时间,为热敏性药物的提取提供了新的强化方法。     

Influence enhancement effect of bi-frequency ultrasonic irradiation by TA fluorescence method

Based on a previous research of cavitation effect under bi-frequency ultrasound irradiation, this paper studies bi-frequency irradiations with similar experimental settings. The additional irradiation sources with frequencies of 1.04MHz, 0.8MHz and 1.7MHz are individually combined with the main ultrasonic irradiation source with frequency of 28kHz to form bi-frequency ultrasonic irradiation. The intensity of 28kHz irradiation was fixed at 12.5W/cm2, while the intensity of the ultrasound at the other three frequencies is varied from1 W/cm2 to 18 W/cm2. It turns out that under the influence of the bi-frequency irradiation, the fluorescence intensity is obviously greater than the sum of those at individual frequencies. So the frequency of the additional sonication strikingly influences the fluorescence enhancement effect. For example, the fluorescence enhancement effect of 1.04MHz is stronger than that of 1.7MHz, and the enhancement effect of 0.8MHz is further stronger than that of 1.04MHz. Under the sonic intensity of 7.9W/cm2, the fluorescence intensity of 1.04MHz is approximately twice that of 1.7MHz while the fluorescence intensity of 0.8MHz is approximately 1.5 times that of 1.04MHz.     

Tumor cell apoptosis induced by nanoparticle conjugate in combination with radiation therapy

Semiconductor nanoparticles conjugated to photosensitizers have been shown to increase tumor cell death with ionizing radiation but the mechanism, particularly the role of photodynamic therapy in the process, was unknown. We used a molecular probe to measure production of (1)O(2) to quantify the component of photodynamic cell-killing in an in vitro system. The intracellular distribution of the nanoparticle conjugate (NC) was determined by the co-localization of nanoparticles and the lysotracker. Induction of apoptosis was measured by the TUNEL assay and western blot analysis of the cleaved caspase-3. As a result, dose-dependent (1)O(2) production was observed with 48 nm NC after irradiating with 6 MV x-rays. A high geometrical coincidence between the fluorescence emission of the nanoparticle and lysotracker was observed using confocal microscopy. Finally, apoptosis, as indicated by the TUNEL stain and cleavage of the caspase-3, was observed in cells treated by both the NC and 6 Gy of radiation but not in cells treated with radiation alone. In conclusion, the cell death induced by the NC in combination with radiation is consistent with a supra-additive effect to radiation-or NC-alone-killing and is mediated by an NC-induced photodynamic therapy mechanism, which is distinctly different from that for radiation-killing alone. By providing a second distinct cell-killing mechanism, this nanoparticle conjugate has great promise as a targeted physical radiosensitizer aimed at overcoming radioresistant tumor clonogens or/and reducing normal tissue toxicity by using a lower ionizing radiation dose.     

基于双频光栅的微分干涉相衬方法

针对传统微分干涉相衬技术对双折射性物体成像会有伪像的问题,用双频闪耀光栅取代传统微分干涉相衬的分光元件诺曼斯基棱镜,设计了一种微分干涉相衬方法.对双频闪耀光栅设计,模拟入射平面波通过它之后的光强分布,结果表明它能产生两束剪切角很小的光.用双频光栅微分干涉相衬方法对纯相位样品模拟成像,仿真结果和物体的相位轮廓一致.分析了...     

Killing of target cells due to radon progeny in the human lung

The dose conversion coefficient (DCC) is used to assess the risk due to inhaled radon progeny in the human lung. The present work uses the microdosimetric approach and determines the linear energy transfer in the target cell nuclei. Killing of target cells was also taken into account through an effect-specific track length model. To focus on the relevant part of the absorbed dose in the cell nuclei, the absorbed dose, which causes cell-killing is discarded in the final calculations of the DCC. Following this approach, the calculated DCC has become 3.4 mSv WLM(-1) which is very close to the epidemiologically derived value of approximately 4 mSv WLM(-1).     

Ignition of acetylene by high-voltage nanosecond discharge

The ignition of acetylene by low-temperature nonequilibrium plasma of a high-voltage nanosecond discharge is experimentally and theoretically studied. The ignition delay time for C₂H₂: O₂ mixtures behind the reflected shock-wave front is measured. It is experimentally shown that discharge initiation leads to a considerable shortening of the ignition delay time. For lean mixtures, this effect is more pronounced. Numerical modeling of discharge and ignition processes under the experimental conditions is carried out. A good agreement between the calculation and experimental results for the ignition delay time is obtained. Analysis of the calculation results shows that the dominant mechanism of the effect of nonequilibrium plasma on ignition is related to the accumulation of atoms and radicals in discharge plasma.     

Measurement of 2,4-toluene diisocyanate concentrations by different samplers

The standard sampling methods for toluene diisocyanate (TDI) only collect total TDI without separating the aerosol and gas phases. There are few other samplers, such as the dual filter, triple filter and annular denuder systems (ADS), which are able to sample the aerosol and gas phases simultaneously. This field study was conducted at two workplaces to access the total 2,4-TDI and the gaseous and aerosol TDI concentrations by different samplers simultaneously. In addition to the standard sampling time of 15 min, sampling was done for 30 and 60 min to study the effect of sampling time on the measured 2,4-TDI concentrations. Test results at two workplaces show that gas-phase 2,4-TDI is the predominant species and the aerosol phase concentration is very small. The measurements using various samplers show that the sampling time influences the sampled TDI concentration considerably which may be due to reaction of TDI with water vapor and polyo in the sampling process. It is evident that as sampling time increases the TDI concentration decreases. Laboratory test was also conducted using pure gas-phase 2,4-TDI to confirm the sampling time effect on the measured concentrations found in the field study.     

钛屑再生制备Al-Ti-B细化剂及其晶粒细化行为的研究

钛及钛合金属于难切削加工材料,生产过程中易产生大量废屑,再生利用钛屑已成为急需解决的问题.本文利用钛屑和氟硼酸钾在铝熔体中反应制备了Al-5Ti-1B细化剂,通过金相显微镜、扫描电子显微镜和X射线衍射仪对细化剂进行分析,研究了细化剂加入量和保温时间对工业纯铝细化效果的影响.研究表明,Al-5Ti-1B细化剂主要由α-Al、TiAl3和TiB2相组成,TiAl3相主要为块状,尺寸为10~30μm;TiB2相均匀分布在合金中,平均尺寸小于2μm。随着细化剂加入量的增加,晶粒尺寸不断减小;当加入量达到0.3%时,晶粒细化效果最好,进一步增大细化剂添加量,晶粒尺寸下降不明显。细化剂保温60 min时,晶粒细化效果良好;保温120 min时,出现了严重的细化衰退现象,晶粒尺寸达到953μm;商业杆状细化剂保温120 min时未出现明显的细化衰退。     

Phonon sattering by nutral donors in n-type silicon

The scattering of phonons by neutral n-type impurities in silicon is studied. Following Keyes, who determined the phonon relaxation time for scattering by neutral impurities in n-type germanium, the relaxation time for the silicon band structure is developed. This scattering comes about due to the large effect of strain on the hydrogen-like donor ground-state energy level. The change in energy of the ground state due to the strain caused by phonons is calculated and the resulting phonon scattering relaxation rate is derived.     

Enzyme Induction by Coumarins

The sodium pentobarbital sleeping time in mice was studied after pretreatment with coumarins (coumarin, 4-hydroxycoumarin, 7-hydroxycoumarin, acenocoumarol, bis-hydroxycoumarin, phenprocoumon and warfarin). All coumarins except bishydroxycoumarin cause a statistical significant reduction of barbiturate sleeping time, hence, have to be considered as enzyme-inducers. The largest enzyme' inducing effect was observed with warfarin.