Chlorophyll-water interaction during oxygen photoevolution at the octane-water interface

The interaction between water and chlorophyll a dissolved in octane has been studied. Factors governing the formation of the hydrated chlorophyll oligomer with the absorption maximum at 742 nm have been identified. It has been revealed that the water photooxidation reaction sensitized by chlorophyll absorbed at the interface requires the presence of water in the octane phase during self-assemblage of the catalytic complex responsible for the reaction.     

Experimental and Simulation Studies of Electro-rheology

Abstract

Electro-rheological fluids are colloidal dispersions that, under the influence of an applied electric field, can show a spectacular increase in yield stress and viscosity. Despite many technological roles for fluids with a viscosity that can be controlled electrically, progress at making them commercially viable products has been slow, partly due to a lack of understanding of this phenomenon at the microscopic level. In this report, simulation and experimental data are combined to provide insights into the microscopic origins of this effect. The simulations produce electric field-induced “strings” of particles that span the electrodes, in agreement with the experimental observation, and are responsible for the major enhancements in the viscosity. The field also causes a strong distortion in the first coordination shell of colloidal particles. The combination of shear and electric field produces a long-range microstructure that is periodically forming and decaying, caused by the competing effects of electric field and shear rate. Comparison with experiment reveals that the Electro-rheological effect is driven by the applied field-induced Stokesian diffusion of the solid particles and relies little on the accompanying Brownian motion.     

Experimental Studies on Plant Metabolism

Treatment of Ricinus communis seeds with GA accelerated the production of reducing sugars and increased the total carbohydrate content. The effect increased progressively with increasing concentration of GA. — GA treatment also induced an earlier appearance of starch which was shown to be completely absent at the early stages of germination. Furthermore, GA accelerated the conversion of oils into carbohydrates. — Analysis of germinating seeds for their nitrogen content showed that whenever an increase in soluble-N due to GA treatment was detected, there was a decrease in protein-N. Breakdown of protein and formation of soluble-N increased progressively with increase in GA concentration. — GA induced variable changes in the length of the radicles and the hypocotyls, the dry weight and the water content of germinating seeds.     

Experimental Studies of Apospory in Ferns

Apospory in Pteridium aquilinum was found to have several novelfeatures, in particular the rapidity of its occurrence. Outgrowthsfrom detached laminae were detected in as little as 3 days.There was no evidence that failure of co-ordination betweencells, senescence of the sporophytic tissue or unfavourableculture conditions effected the initiation of outgrowths asearlier workers have suggested. The response of Thelypterispalustris was notably slower and more in line with earlier reportsof apospory. Marsilea vestita appeared to be incapable of anyform of aposporous behaviour. The only feature common to all occurrences of apospory in leavesof wild-type ferns is the severance of the lamina from the mainbody of the plant. It is proposed that this may deprive thecells of regulatory substances which maintain the activationof sporophytic genes. The results are also considered in relationto the phase changes in homosporous and heterosporous plantsand the behaviour of fern protoplasts in culture. apospory, ferns, Pteridium aquilinum, Marsilea vestita, Thelypteris palustris     

压力探针技术在植物水分关系研究中的运用

压力探针（pressure probe）技术最初设计时用于测定巨型藻类细胞的膨压,后来转到对高等植物细胞的膨压及其他水分关系参数的测定,现在已发展成为植物生理学和生态学研究中的一种多用途技术。它可以在细胞原位测定水分及溶质跨膜运输及分布情况。能够在不离体的植物中测定水通道的活性。新近发展的木质部压力探针是惟一可以直接测定导管或管胞中负压的技术。文章介绍该技术基本原理及其在植物水分生理学研究中的应用。     

A World Divided? Studies of Gender Relations in Modern Greece

This paper explores anthropological and sociological representations of gender relations in modern Greece, in the light of recent re-examination of the perspective and inherent biasses of such representations. I argue that the dichotomous schema used in many studies obscure the complexities of gender relations Moreover, further analysis of the centrality of the family in economic and political activities suggests both ethnocentrism and androcentrism in studies of modern Greece.     

Experimental and Theoretical Studies of Calcium Fructoborate

Calcium fructoborate samples of composition Ca(C₆H₁₀O₆BO)₂·3.5H₂O were characterized by chemical analysis, infrared and Raman spectroscopy, and thermoanalytical (thermogravimetric and differential thermal analysis) data. Theoretical studies, using density functional theory, were made for seven different structural models of the fructoborate moiety, and the most stable structure could be derived from these calculations. The results of the theoretical study also allow improving the assignment of the vibrational spectra of the compound.