CONTROLLING THE 3D NANOSCALE ORGANIZATION OF BULK HETEROJUNCTION POLYMER SOLAR CELLS

  In this study, the three dimensional nanoscale organization in the photoactive layers of poly(3-hexylthiophene) (P3HT) and a methanofullerene derivative (PCBM) is revealed by transmission electron tomography. After annealing treatment, either at elevated temperature or during slow solvent evaporation, nanoscale interpenetrating networks are formed with high crystalline order and favorable concentration gradients of both components through the thickness of the photoactive layer. Such a tailored morphology accounts for the considerable increase of the power conversion efficiency in corresponding solar cell devices.     

CONTROLLING THE 3D NANOSCALE ORGANIZATION OF BULK HETEROJUNCTION POLYMER SOLAR CELLS

In this study,the three dimensional nanoscale organization in the photoactive layers of poly(3-hexylthiophene) (P3HT) and a methanofullerene derivative (PCBM) is revealed by transmission electron tomography.After annealing treatment,either at elevated temperature or during slow solvent evaporation,nanoscale interpenetrating networks are formed with high crystalline order and favorable concentration gradients of both components through the thickness of the photoactive layer.Such a tailored morphology acco...     

电池结构对叶绿素电池光电性质的影响

叶绿素是绿色植物中吸收太阳能进行光合作用的主要色素,它在可见光范围内有很好的吸收特性^[1]。人们为了充分利用太阳能为人类造福开始了光合作用模拟,70年代后以叶绿素为光敏剂的研究成了科学家的热门课题。     

ULTRASTRUCTURAL STUDY OF THE HATSCHEK''''S PIT EPITHELIAL CELLS OF AMPHIOXUS

The authors have observed, using an electron microscope, that the number of thesecretory granules and the development of various organelles in the apical epithelial cellof the Hatschek's pit showed a positive correlation with the gonadal development andmaturity. At the same time, only the epithelial cells respond to GnRH-A(gonadotropin-releasing hormone analogue). Both cytological and endocrinological experiments demon-strate that the cell may be the primitive gonadotropic cell of amphioxus.     

THE FATE OF PYRIMIDINE DIMERS IN THE DNA OF ULTRAVIOLET-IRRADIATED CHINESE HAMSTER CELLS

Abstract —As an aid to understanding the relationship between dimer repair and cellular recovery, we have studied dimer removal and replication of dimer-containing DNA in Chinese hamster ovary (CHO) cells irradiated with ultraviolet light (254 nm). These investigations demonstrated that (1) dimers are not excised as polynucleotides of less than 500,000 mol. wt, (2) fractionation of the ultraviolet dose does not enhance dimer excision, (3) dimer-containing DNA is replicated in ultraviolet-irradiated CHO cells, and (4) the dimers are conserved in the replicated DNA. These findings support the proposed mechanism of bypass of photoproducts during DNA replication in mammalian cells.     

高精密饱和硫酸镉标准电池的研制

本文提出从工业品原料提纯制备高精密标准电池的方法。有40个酸性电池(硫酸浓度0.0490N),在1973～1979年间,于规定时间测定电动势值,每年平均上升0.33μV.初步分析了影响电池电动势值稳定性的各种因素,提出了实验数据。     

FLUORESCENCE OF PHYTOCHROME IN THE CELLS OF DARK-GROWN PLANTS AND ITS CONNECTION WITH THE PHOTOTRANSFORMATIONS OF THE PIGMENT

Abstract Fluorescence of phytochrome is found in the cells of etiolated monocotyledonous and dicotyledonous plants. The red light-absorbing form of phytochrome (P_r) fluoresces at 77 K with a yield 0.3±0.1 and maxima at 672–673 nm and 684–686 nm in the excitation and emission spectra, respectively. The emission is characterized by the sharp temperature dependence of its intensity, its high (～ 40%) polarization, and the violation of the mirror symmetry rule. Connection of the fluorescence with P_r photoreactions is followed in the interval 77–293 K. A P, photoproduct, lumi-R, is fluorescent with maxima at 696 nm and 705 nm in the excitation and emission spectra; the far-red light absorbing form of phytochrome (P_fr) is practically nonfluorescent. Three isochromic emitting P_r species are present differing in their photochemical properties: P_r1 and P_r2 which phototransform irreversibly and reversibly at T 170 K into lumi-R, and lumi-R₂, respectively, and P_r3 which undergoes photoconversion only at T > 240 K. The activation energies of P_r2 and P_r3 photoreactions are evaluated to be 2.9–3.3 kJ/mol and 26 kJ/mol. Complex dynamics of changes of P_r fluorescence and of the extent of its decrease in the photoconversion P_r? P_fr in germinating pea and bean seeds suggests the existence of two P_r pools one of which is incapable of P_r? P_fr phototransformation. Thus, the developed fluorescent method of phytochrome assay and investigation in the cell revealing multiplicity of phytochrome states in vivo proves to be very sensitive (about 1 ng) and informative.     

GENETIC TOXICOLOGY OF THE PHOTOSENSITIZATION OF CHINESE HAMSTER CELLS BY PHTHALOCYANINES

Chloroaluminum phthalocyanine (CAPC) was recently shown to photosensitize cell killing in culture and tumor destruction in vivo. Because this compound is potentially useful in the photodynamic therapy of cancer, its properties as a genotoxic agent were evaluated. Applying the technique of alkaline elution to study DNA integrity, it was found that CAPC could produce single-strand breaks in the DNA of Chinese hamster cells after exposure to white fluorescent light. At equicytotoxic doses, the number of DNA strand breaks produced by CAPC photosensitization was about three times lower than that induced by X-irradiation. During incubation in growth medium after exposure to CAPC-plus-fluorescent light, cells rejoined DNA strand breaks at a rate similar to that observed after X-irradiation. Resistance to 6-thioguanine (6-TG') or to ouabain (OUA') were used as end points of mutagenic potential. Following a treatment that caused -90% cell killing, there was a slight mutagenic effect, i.e. the frequencies were increased by -40% above the background or spontaneous mutations. However, this enhancement was not statistically significant. Taken together, the foregoing, plus an earlier observation that there is no variation in the sensitivity of cells to CAPC + light through the cell cycle, lead to the inferences that DNA damage does not play a major role in cell killing and that the mutagenic potential of this treatment is small.     

有机太阳能电池的染料结构与光电性能关系的研究

本文用自动测试系统探讨了菁染料和方酸染料的化学性质、结构与其光伏效应之间的关系, 从理论上讨论了载流子光致发生机理。发现在给电子体-受电子体发色团染料中, 光伏效应有显著的取代基效应, 同时观察到量子效率随给电子杂环的碱性及分子离子势等有一定变化规律。讨论了方酸染料的聚集态。     

电极表面状态对原电池影响的热力学分析

１前言我们知道，超细微粒及其材料具有许多优异的物理化学性质［１～６］；这是因为随着物质分散度的增加，比表面积和表面能也相应增加，从而产生了强烈的表面效应，导致体系在分散状态时的物理化学性质与块状时相比发生了显著变化。我们知道，表面粗糙的金属容易发生电...     

ROLE OF SPECIFIC CELLULAR TARGETS IN THE HEMATOPORPHYRIN-SENSITIZED PHOTOINACTIVATION OF MICROBIAL CELLS

Abstract The hematoporphyrin-sensitized photoinactivation of Candida albicans is mainly carried out by porphyrin molecules which are present in the cell-incubation medium. Photoexcitation of hematoporphyrin by visible light appears to cause limited biochemical and functional alterations of the cytoplasmic membrane; this allows the penetration of the dye into the cell, with a consequent important photoinactivation of the mitochondria. The latter process is of critical importance for the decrease in the survival of the irradiated cells.     

EFFECT OF PHOSPHATE AND CHLORIDE ON THE PHOTODYNAMIC INACTIVATION OF YEAST CELLS

Abstract— Yeast cells are inactivated by treatment with hematoporphyrin and light. The inactivation, which is mediated by singlet oxygen (¹O₂), is enhanced by the presence of phosphate and chloride. Neither phosphate nor chloride has any influence on the yield of ¹O₂. Possible mechanisms for the enhancement are briefly discussed.     

THE USE OF SPIN LABEL OXIMETRY IN THE STUDY OF PHOTODYNAMIC INACTIVATION OF CHINESE HAMSTER OVARY CELLS

Spin label oximetry has been used to study the effects of photosensitizer hematoporphyrin on oxygen consumption in Chinese hamster ovary cells. These measurements demonstrate that, in the presence of the sensitizer, there occurs (i) an increase in total oxygen consumption during irradiation and (ii) a decrease in oxygen consumption following irradiation. These results are attributed to the effects of photosensitized oxygen consumption and decreased cellular respiration due to cell inactivation. Thus the inhibition of oxygen consumption after irradiation was shown to correlate with decreased cell survival measured in cell culture experiments. Possible mechanisms of inactivation and extensions of the oximetric approach are discussed.     

LASER-UV-MICROIRRADIATION OF CHINESE HAMSTER CELLS: THE INFLUENCE OF THE DISTRIBUTION OF PHOTOLESIONS ON UNSCHEDULED DNA SYNTHESIS

Abstract— Fibroblastoid Chinese hamster cells synchronized by mitotic selection were microirradiated in G1, using a low power laser-UV-microbeam (λ= 257 nm). The incident energy was either concentrated on a small part of the nucleus (mode 1) or distributed over the whole nucleus (mode 11). Using the same incident UV energy, the local UV fluences were estimated to differ by two orders of magnitude. Following microirradiation the cells were incubated with [³H]-thymidine for 2 h and thereafter processed for autoradiography. Silver grains were concentrated over the microirradiated part after mode 1 and distributed over the whole nucleus after mode 11 irradiation. To quantify the amount of unscheduled DNA synthesis, the number of grains per nucleus was determined. It increased with the total incident energy, but was not or only slightly affected by the mode of microirradiation, if appropriate autoradiographic conditions were used. The findings suggest that within the investigated range of energy densities (2.7–1000 J/m²), the total amount of unscheduled DNA synthesis depends on the total number of pyrimidine dimers but not on their distribution in nuclear DNA.     

ELECTROFUSION OF IBRS2 CELLS AND THE STUDY OF THEIR FUSION PROCESS

IBRS2 epithelial cells in monolayer culture fused at a very high frequency when exposed to high-voltage electric pulsing fields. Exposure to four repetitive electric pulses of about 1.7 kilovolts per centimeter with a duration of 100 microseconds caused more than 90 percent of the cells to become fused (multinucleate) when 1 millimolar magnesium was present in the pulsing medium. Magnesium and calcium ions in the pulsing medium had a very strong effect on the electrofusion of IBRS2 cells. Magnesium could increase not only the electrofusion yield but also the stability of the cells under the conditions of electrofusion. In contrast, calcium inhibited electrofusion and decreased the stability of the cells. Careful microscopic observation revealed the electrofusion of IBRS2 cells to be very complex, dynamic process undergoing many interesting changes. A possible explanation for the process and mechanism of electrofusion of IBRS2 cells was proposed in agreement with the experimental observation.     

MODEL CONSIDERATIONS OF THE LIGHT CONDITIONS IN NONCYLINDRICAL PLANT CELLS

Abstract— A geometric model of a noncylindrical plant cell has been constructed using optical and geometrical parameters obtained for the cells of Funaria hygrometrica and Lemna trisulca leaves. The distribution of the incident light intensity and the absorption profile in the monomolecular photoreceptor layer on the walls of the model cell irradiated with the parallel beam have been calculated. Calculations were performed for two surrounding media with refractive indices of 1.33 (water) and 1.00 (air). Various chloroplast arrangements were considered. The course and kinetics of the phototactic movements of Funaria and Lemna chloroplasts have been discussed on the basis of the results obtained. The best agreement between the theoretical and experimental data is obtained by assuming that the transition moments at 450 nm of the dichroic photoreceptor molecules are oriented parallel to the surface of the cell wall.     

DARK ADAPTATION OF HORIZONTAL CELLS IN THE TELEOST FISH RETINA

The dark adaptation behaviors of rod-driven and cone-driven horizontal cells were exam-ined by analyzing their light responses recorded intracellularly in the intact, immobilizedcarp, and compared with that of the electroretinographic b--wave recorded simultaneously.Like the b--wave, the light responsiveness of rod horizontal cells increased gradually withtime in the dark and attained a steady level at 60 min. On the other hand, cone horizontalcells initially increased in light responsiveness in the first 10 min, but thereafter decreasedsteadily so that the response amplitudes of these cells to bright light flashes were only 3--5 mV.The results suggest that cone horizontal cells are strongly suppressed in prolonged darkness.     

THE EFFECT OF NATIVE ISOLOGOUS DNA ON THE INCORPORATION OF THYMIDINE-H3INTO U.V. IRRADIATED L-STRAIN CELLS

Abstract— The effect of highlypolymerized deoxyribonucleic acid (DNA) upon the incorporation rate of thymidine-H³ into DNA of recipient L -strain cells has been studied. The rate of incorporation of thymidine-H³ is much faster in controls and irradiated cells than in irradiated treated with isologous DNA.