染料敏化纳米太阳能电池

本文介绍了染料敏化纳米太阳能电池的结构和原理,对纳米TiO₂膜、敏化染料、空穴传输材料的研究进展进行了综述.     

PHOTODYNAMIC THERAPY WITH PHOTOFRIN II INDUCES PROGRAMMED CELL DEATH IN CARCINOMA CELL LINES

Abstract The mode of cell death following photodynamic therapy was investigated from the perspective of programmed cell death or apoptosis. Human prostate carcinoma cells (PC3), human non-small cell lung carcinoma (H322a) and rat mammary carcinoma (MTF7) were treated by photodynamic therapy. An examination of extracted cellular DNA by gel electrophoresis showed the characteristic DNA ladder indicative of internucleosomal cleavage of DNA during apoptosis. The magnitude of the response and the photodynamic therapy dosage required to induce DNA fragmentation were different in PC3 and MTF7. The MTF7 cells responded with rapid apoptosis at the dose of light and drug that yielded 50% cell death (LD₅₀). In contrast, PC3 showed only marginal response at the LD₅₀ but had a marked response at the LD₈₅. Thus, apoptosis did not ensue as quickly in PC3 as in MTF7. The H322a cells were killed by photodynamic therapy but failed to exhibit any apoptotic response. The results also suggested that apoptosis in these cell lines has a minor requirement for de novo protein synthesis and no requirement for de novo RNA synthesis. This study indicates that although apoptosis can occur during photodynamic therapy-induced cell death, this response is not universal for all cancer cell lines.     

癌细胞的热化学研究

生物热化学是一门新兴的交叉学科,它从热化学的角度进行生物学方面的研究。组织细胞常态生长的热谱图反映了组织细胞新陈代谢的情况,热谱图峰高和组织细胞新陈代谢的活动强度成正比。但到目前为止,组织细胞的生长过程热谱图的测量国内还未见报导,因为其正常生长的条件要求较高,测量重复性差。本文在达方面进行了探索性研究。实验部分本工作使用的是MS80标准型Calvet微量量热计,工作温度为37℃,放大器用10μV档,     

一种新的双光系统透明电极电池

植物光合作用在其叶绿体的光合作用膜上进行。它有两个串联着的光系统(PSII和PSI)。PSII在膜的一侧,吸收波长相当于680nm的光子激发电子并产生空穴,空穴将水氧化得氧。电子经过一系列的下坡传送,暗反应合成ATP,到处于膜另一侧的PSI。PSI吸收波长相当于700nm的光子,再次将电子激发,经过第二个系列的下坡传送,暗反应将NADP还原为NADHP。NADHP和ATP最终将CO₂还原为碳水化合物。     

AN FMN-PHOTOSYSTEM I PHOTOVOLTAIC CELL

Abstract— We have made a photovoltaic cell using Photosystem I subchloroplast particles isolated according to the method of Shiozawa et al. (1974). The particles were placed on a filter between two compartments one of which contained the electron donor, K₄Fe(CN)₆ and the other the electron acceptor, FMN. Upon illumination with white light ( I = 80 W/m²) a potential of 300 mV was observed across a 3000 Ω load resistance. Both Photosystem I photochemistry and direct photoreactions of FMN contribute to the process. A power output of 20 μW was observed for a 2 cm² filter containing 60 μg chlorophyll. This corresponds to 0.1 W/m². The power efficiency was 0.13%. The short circuit current was 108 μA.     

A PHOTOSYSTEM I-PHENOSAFRANINE SOLAR CELL

Abstract Bacteriophage λ_vir was inactivated when it was irradiated with near-UV light in the presence of chlorpromazine. DNA strand breakage in the treated phage was indicated by alkaline sucrose gradient centrifugation. The number of the breaks was increased with increasing fluence. Although the inactivation rate was enhanced with a decreasing salt concentration in the reaction mixture and under a nitrogen atmosphere, the number of the strand breaks was not altered in either case. Therefore, the DNA strand breakage is not a sole lethal damage in the treated phage. The addition of NaN₃ repressed the inactivation and the reaction in a D₂O medium enhanced the inactivation even if the reaction mixture was irradiated under anaerobic conditions. Under anaerobic conditions, the inactivation occurs presumably via a radical mechanism.     

分次降压法研究微孔聚合物发泡的成核及增长过程

将环烯烃共聚物样品在超临界CO2 条件下饱和后 ,先将体系降至一中间压力 ,而后采用 4种不同的方法分次降压和快速冷却 .通过 4种降压和冷却模式的比较 ,初步研究了快速降压法微孔发泡的成核及增长过程 .并得到了几种新颖结构的微孔 ,如具有过渡层结构以及直径呈双峰分布的微孔等 .研究表明 ,泡孔充分增长过程中绝大部分气核消失或合并 ,只有很少一部分最终生长为稳定的泡孔结构 ,而不同的泡孔增长过程对最终的泡孔结构有很大影响 .二次成核只有在一定的压降范围内才能发生 .两次降压得到的泡孔结构与该降压幅度下气体溶解度的变化密切相关     

ULTRAVIOLET RADIATION INHIBITS BOTH ACCESSORY CELL AND RESPONDER T CELL FUNCTION IN THE PROLIFERATIVE RESPONSE TO HAPTENATED-SELF

Abstract— Photoprotection i. e. the increased resistance of the cells preilluminated with near ultraviolet light (300–380 nm) to the lethal action of 254 nm radiations is observed in wild-type Escherichia coli B cells (which exhibits the Fil phenotype) but requires either an integrated prophage or a rec A mutation to be detected in E. coli K12 strains. Here we have demonstrated that significant photoprotection occurs in an E. coli K12 rec A⁺ cell containing the Ion allele which is responsible for filamentous growth (Fil phenotype) after 254 nm irradiation. The Fil phenotype can be suppressed by the sfi A of sfi B suppressor genes. Since the E. coli K12 rec A⁺ Ion sfi B strain exhibits no more photoprotection, these data support the conclusion that in Ion strains photoprotection is due to the abolition of the 254 nm induced filamentation by the near ultraviolet treatment. In addition, we show here that near ultraviolet illumination of the cells leads to a severe restriction of the bulk protein synthesis, as well as of the inducibility of β-galactosidase and tryptophanase. These effects are observed only in nuv ⁺ cells that contains 4-thiouridine the chromophore responsible for photoprotection. We propose that in Ion (lysogenic) strains, photoprotection is due to prevention of the SOS response. During the growth lag, the low residual level of protein synthesis does not allow the induction of the SOS response and accordingly prevents filamentation (the lytic cycle). Concomitantly the SOS triggering signals are eliminated via DNA repair.     

微流控芯片上的细胞分析研究进展

近年来,微流控分析系统(μTAS)在生物细胞分离领域的发展引起了广泛的关注。微流控芯片的微米级尺寸的通道适合于单细胞样品的引入、操控、反应、分离和检测,已经在微芯片上实现了上述功能,并将这些功能集成在具备毛细管电泳分离功能的微芯片上。     

THE EPIDERMAL CELL KINETIC RESPONSE TO ULTRAVIOLET B IRRADIATION COMBINES REGENERATIVE PROLIFERATION AND CARCINOGEN ASSOCIATED CELL CYCLE DELAY

The cell cycle traverse of epidermal basal cells 24 h after in vivo exposure of ultraviolet B (UVB) irradiation was studied by immunochemical staining of incorporated bromodeoxyuridine (BrdU) and bivariate BrdU/DNA flow cytometric analysis. The results were compared with the cell kinetic patterns following topical application of the skin carcinogen methylnitrosourea (MNU) as well as the skin irritant cantharidin. Hairless mice were injected intraperitoneally with BrdU 24 h after treatment of their back skin with either a minimal erythema dose of UVB, or a single application of MNU or cantharidin dissolved in acetone. The cell cycle traverse of the BrdU-labelled cohorts of epidermal basal cells were then followed for the subsequent 12 h. At 6 h after BrdU-injection, when all labelled cells in the control group as well as in the cantharidin group had left the S phase, the bivariate distributions of the UVB-exposed and the MNU group showed that BrdU-positive cells were still present in S phase. Hence, UVB irradiation, similar to the carcinogen MNU, prolonged the S phase duration in some of the basal cells. At 12 h after pulse labelling, however, BrdU-positive cells from UVB-exposed mice were re-entering S phase from G1 phase, indicating that UVB irradiation induced a shortening of the cell cycle time as well, similar to the response observed after cantharidin. The present data can not tell whether these cells also were delayed in S phase. Thus, the cell cycle traverse in hairless mouse epidermis 24 h after in vivo exposure to UVB seemed to be a combination of the cell kinetic effects following chemical skin carcinogens and skin irritants. UVB irradiation induced both a delay in transit time through S phase, probably due to DNA damage and subsequent repair, as well as a reduction in the total cell cycle time consistent with rapid regenerative proliferation.     

A CONVENIENT IRRADIATION CELL FOR FERRIOXALATE ACTINOMETRY

Abstract— A calibrated volumetric optical cuvette is described which both simplifies the technique and improves the precision of potassium ferrioxalate actinometry. The cuvette is used both for irradiation of the actinometer solution and for in situ dilution and chemical developing of the irradiated aliquot. The technique permits all but one manipulation to be carried out in total darkness, thus protecting the actinometer solutions from ambient light. The method can be extended to any actinometric procedure and the volumetric cuvettes are very useful in a variety of other spectrophotometric applications.     

MEASUREMENT OF CELL LYSIS BY LIGHT SCATTERING

Abstract— A method is presented which is capable of continuously monitoring the degree of hemolysis in erythrocyte suspensions too dilute to be monitored by conventional light transmission techniques. Scattered light is used to non-destructively assess hemolysis in sparse monolayers which are particularly well suited to many photohemolytic studies. The small angle scattering (<10°), measured here, shows a transient decline as cells settle in a culture dish and then is constant if no lysis occurs. Lysis is indicated by a decrease in scattered light to < 20% of initial intensity when lysis is complete. The light used to monitor lysis is restricted to wavelengths longer than 700 nm which is outside the absorption band of many. photosensitizers of current interest, and is a wavelength range at which light scattering is relatively independent of changes in cell volume. In photohemolytic studies with phloxine B lysis values from light scattering are shown to correlate well with lysis values from hemoglobin release. An apparatus is described which is capable of periodically measuring lysis in eight suspensions without intervention by the experimenter.     

IPN''''s PVA AND ITS CELL GROWTH PROPERTY

6 kinds of IPN's PVA were synthesized by using different monomers of HEMA, MAA and MMA. The effect of adding polysaccharide was also studied. The cell growth on them were determined and compared. The results showed that the cell growth property of the IPN's PVA with hydrophobic monomer of MMA is better, and it can be improved further by adding hyaluronic acid.     

PORPHYRIN PHOTOSENSITIZATION OF MULTI-DRUG RESISTANT CELL TYPES

The P388 murine leukemia and P388/ADR, a subline expressing the multi-drug resistance (MDR) phenotype, were examined with regard to the role of MDR as a determinant of responsiveness to photodynamic therapy in vitro. Mesoporphyrin was used as a model substrate. We found no differences in porphyrin accumulation nor transport alterations associated with exposure of P388/ADR cells to the verapamil analog DMDP. There was a significant correlation between photodamage to mitochondria vs loss of cell viability in both cell lines, and LD50 sensitizer levels were not significantly different in P388 vs P388/ADR. P388/ADR cells were partly resistant to porphyrin-catalyzed photodamage to amino acid transport, but this result was not associated with differences in sensitizer localization, as indicated by fluorescence studies. Moreover, photodamage to membrane transport was not associated with loss of viability. These studies suggest that cells which express the MDR phenotype are unlikely to be cross-resistant to photodynamic therapy.     

四膜虫细胞与过渡元素系

本文选用淡水纤毛虫—梨形四膜虫Sl株作实验,进一步研究过渡元素对细胞群体生长繁殖和抑制的影响。以未加元素作对照组比较时间t=37小时处各生长曲线的N/N_0值,得到细胞相对增殖率R与周期表中过渡元素浓度C的系列图。发现过渡元素对细胞生长分裂的促进浓度与他们在海水中的丰度之间,存在着相应消涨的关系,从而支持了生命起源和进化的海洋说;并从金属离子的水解形式和离子势方面,阐述第一过渡系元素在低浓度时的刺激促进作用与周期表中原子序数的依存关系。     

癌细胞培养的热化学测量

我们用微量量热学方法对小鼠乳腺癌细胞(MA 782/5 S-1801)在离体培养状态下进行了热化学测量,测得单个癌细胞此状态下代谢的发热功率_平均为35.1 pW/cell。以此为对照加入某种抑制剂(BNA)对癌细胞某代谢环节进行抑制时,进行同样的测量,发现该癌细胞代谢发热功率明显下降,平均结果为23.2pW/cell。这些结果对进一步研究癌细胞代谢的机理及筛选抗癌药剂将有一定的意义。     

新式夹心型光透薄层光谱电化学电解池

本文设计了一种新式夹心型光透薄层紫外-可见光谱电化学池。该池采用铂网工作电极,两侧平行放置铂片为对极置于同一石英窗口夹层中,同时以聚四氟乙烯隔离膜作为边际限制器,结合池内小孔道设置内参比点进行精确的电位控制,具有理想的光谱电化学响应。利用循环伏安、循环电位-吸收、恒电位现场光谱、双电位跃-计时电量、双电位跃-计时吸收等技术,对铁氰化钾在氯化钾溶液中的行为进行了表征。     

能够促进细胞黏附的生物活性表面的制备

报道了一种能够促进细胞黏附的生物活性表面的制备方法.首先通过表面引发原子转移自由基聚合方法在硅表面接枝了聚(N-甲基丙烯酰氧基琥珀酰亚胺)(PNMASI)聚合物刷.随着反应时间的增加,接枝层厚度基本呈线性增长,表明聚合反应具有一定的可控性.蛋白质吸附测试表明PNMASI改性后的表面具有高密度固定生物分子的能力.同时,通...     

JONES型电导池测量的LCR电桥等效电路选择

JONES电导池系统的交流阻抗由电极过程的相关阻抗和电极间溶液的电阻两部分组成,可用适当的等效电路模拟。采用LCR电桥测量JONES电导池中溶液的电阻时需要选择合适的等效电路为模型解析测量的交流阻抗。通过等效电路的分析发现,选择串联电路作为LCR电桥的解析等效电路测量JONES型电导池中溶液的电阻时引入的误差比并联电路小。     

具有内皮细胞选择性的细胞膜仿生支架材料的研究

利用AIBN引发自由基反应,由单体2-(甲基丙烯酰氧基)乙基-2-(三甲基氨基)乙基磷酸酯(MPC)、甲基丙烯酸十八酯(SMA)、对硝基苯氧羰基聚乙二醇甲基丙烯酸酯(MEONP)合成了一种新型类细胞膜仿生涂层材料.MPC可以阻抗非特异性吸附;MEONP可以结合抗体或多肽促进特异性识别.通过表面固定的方法引入多肽序列Arg-Glu-Asp-Val(REDV),使涂层具有内皮细胞选择性.核磁、紫外吸收、红外光谱表征证实聚合物的组成以及REDV多肽在表面的固定;并通过血浆复钙化实验表征涂层的血液相容性.细胞黏附与增殖实验反映REDV多肽构建的涂层表面具备良好的特异性识别并结合内皮细胞的能力.