The Audio Frequency Conductance Study of Some Metal Succinate Salts in Aqueous Medium at Different Temperatures (Part Ii: Zinc, Nickel and Cobalt Succinates)

The electrical conductances of aqueous solutions of zinc, nickel and cobalt succinates have been measured at four temperatures in the temperature range from 298.15K to 313.15K. The limiting molar conductances (Λo), association constants (KA) and the closest distances of approach (a) were calculated using the complete and modified forms of Fouss-Hsia (F/H) and Pitts (P). Quantitative results showed that these salts do not behave as "strong" electrolytes, and that their dissociations are far from complete. The abnormally law conductances of these electrolytes are due to the ion pair formation. The Walden product values, as well as the standard thermodynamic functions (DHo, DGo, DSo) for association reactions have been evaluated

Effect of the aqueous extract of Banana Fruits Peal Musa paradisiaca on Mitosis in Plant and Mammalian cells

The aqueous extract of banana fruits peal was tested for its effect on mitosis . The root tips of Allium cepa were used as plant test system and the bone marrow cells of the albino mice Mus musculus were used as mammalians test system in vivo .Root tips of Allium cepa were treated for four hours with five concentrations of the extract (5 , 10 , 20 , 40 ,60 mg / ml.).The Metaphase was arrested in all the treatments , the highest percentage ( 100 % ) was recorded in the first concentration , the last concentration caused stickiness and clumping of the chromosomes. The treatments did not cause significant difference in the mitotic index. The peals extract (5 mg /ml) was compared with the extracts of fruits bulb, leaves and roots of banana plant, it was found that the extract of fruits peal is the best considering the highest percentages of arrested Metaphase in the root tips cells. The albino mice Mus musculus were injected intraperitonial with the peals extract ( 0.01 , 0.02, 0.04, 0.06, 0.08 mg / gm body weight), the percentages of arrested Metaphase in the bone marrow of these animals were comparable to the recorded percentages when the animals were injected with colchicine ( 0.01 mg / gm b.w.) .This study revealed the antimitotic activity of the aqueous extract of banana fruits peal on both the plant and mammalian cells in vivo. Studies will be conducted to investigate the effect of the extract and its components on the proliferation of cancer cells in vitro and in vivo

Optical properties and first-principles study of CH₃NH₃PbBr₃ perovskite structures

Abstract Solution-processed organic–inorganic hybrid perovskites have attracted attention as light-harvesting materials for solar cells and photonic applications. The present study focuses on cubic single crystals and microstructures of CH₃NH₃PbBr₃ perovskite fabricated by a one-step solution-based self-assembly method. It is seen that, in addition to the nucleation from the precursor solution, crystallization occurs when the solution is supersaturated, followed by the formation of a small nucleus of CH₃NH₃PbBr₃ that self-assembles into bigger hollow cubes. A three-dimensional (3D) fluorescence microscopy investigation of hollow cubes confirmed the formation of hollow plates on the bottom; then, the growth starts from the perimeter and propagates to the center of the cube. Furthermore, the growth in the (001) direction follows a layer-by-layer growth model to form a complete cube, confirmed by scanning electronic microscopy (SEM) observations. Two-dimensional (2D)–3D fluorescence microscopy and photoluminescence (PL) measurements confirm a peak emission at 535 nm. To get more insights into the structural and optical properties, density functional theory (DFT) simulations were conducted. The electronic and optical properties calculated by DFT are in agreement with the obtained experimental values. The density-of-state (DOS) calculations revealed that the valence band maximum (VBM) consists of states contributed by Br and Pb, which agrees with the X-ray photoelectron spectroscopy valence band (XPS VB) measurements

A sociologia urbana, os modelos de análise da metrópole e a saúde coletiva: uma contribuição para o caso brasileiro Urban sociology, analytical models for metropolisses, and collective health: a contribution to the Brazilian case

À luz da antiga relação entre a epidemiologia e o espaço geográfico e dos diversos modelos de produção das cidades, apresenta-se uma sistematização das noções de espaço/território, a partir da década de 1970 no Brasil. Discutem-se os principais modelos analíticos das grandes cidades brasileiras, cujas raízes conceituais encontram-se em disciplinas como a sociologia urbana, a geografia humana, a economia regional e o planejamento urbano. Sugere-se que a distribuição de investimentos públicos guarda relação com a estrutura social cristalizada no espaço. Procura-se ampliar as bases de um diálogo entre a literatura que apóia as análises das chamadas desigualdades socioespaciais e a saúde coletiva. Apresenta-se sugestão de arcabouço para o desenvolvimento de tipologias de análise socioespacial. Considera-se que se encontram disponíveis diversas técnicas computacionais que popularizam o emprego de variáveis passíveis de expressão espacial. No entanto, essas facilidades ressentem a falta de um aporte mais sociológico, ou humanístico.<br>In light of the historical relationship between epidemiology and geographic space and the relevance of a detailed examination of models for the production of cities, this article systematizes the notions of space/territory that have influenced urban sociology since the 1970s in Brazil. The principal analytical models for large Brazilian cities are discussed in such disciplines as urban sociology, human geography, regional economics, and urban planning. The article suggests that the distribution of public investments bears a close relationship to the social structure crystallized in space. The text attempts to expand the basis for a dialogue between the literature underlying the analyses of so-called socio-spatial inequalities and collective health. Two key points are raised in the article: there are increasingly available computational techniques leading to more widespread use of variables that are amenable to spatial expression; but, these facilities lack a more sociological or humanistic approach for both the methodological design and the results of such analyses