Preparação de carbonos porosos por moldagem sequencial

Porous carbons have received great attention because of their potential use as adsorbents, sensors, catalytic supports and others. Among the available methods for preparing these solids, the sequential templating emerges as an efficient way to tail carbon materials, with large specific surface areas, high porosity, controlled narrow pore size distribution and different functional groups. The template process is based on the infiltration of carbon precursors into the pores of inorganic frameworks. This work reviews the most important variables involved in the sequential template process to prepare micro, meso and macroporous carbon with tailored properties as well as their applications.

Síntese, caracterização e estudo da atividade inibitória de novas dialquilfosforilarilidrazonas sobre o crescimento de tripanossomatídeos

A new series of dialkylphosphorylhydrazones was synthesized through the condensation of aromatic aldehydes with different phosphorylhydrazines. All synthesized compounds were characterized by IR, ¹H-NMR, 13C-NMR and 31P-NMR spectroscopies. The in vitro investigation of the activity of these compounds against Leishmania amazonensis promastigotes and epimastigotes of T. cruzi, showed an efficient inhibition of proliferation, at non toxic concentrations to mammalian cells. The results have shown some derivatives as potential antiparasitic agents against trypanosomatids.

Estudo da emissão por fluorescência de ultravioleta na quantificação de um inibidor de corrosão do tipo sal de amônio quaternário em água

Quaternary ammonium salts are the corrosion inhibitors most frequently used by the oil industry. In this study, the ultraviolet fluorescence technique was evaluated for the analysis of a quaternary ammonium salt in water as a corrosion inhibitor. The comparison with standard salt showed that an alkyl aryl quaternary ammonium salt is the main fluorophore, with emission maxima at 306 and 593 nm. The best instrumental parameters were: width of excitation and emission slits of 10 and 15 nm, respectively, and scan rate of 10 nm min-1. The presence of aromatic compounds and biocides affects the analysis of corrosion inhibitors.

Zeólitas hierarquicamente estruturadas

This review presents the main characteristics and properties of microporous (zeolites) and ordered mesoporous materials, focusing on structural aspects and preparation. In addition, their use as heterogeneous catalysts are also discussed, with emphasis on their advantages and disadvantages. Due to difficulty in application of zeolites in the conversion of bulky molecules, the most relevant strategies of synthesis for the preparation of zeolitic materials with hierarchical pore structure was also analyzed, which allow this limitation to be overcome.

Resgatando um método eficiente para determinação do ponto de ebulição de substâncias orgânicas: percolador versus Siwoloboff

The aim of this paper was to revive the accurate determination of the boiling point of organic compounds using the percolator technique developed in the 1960s. Although this method is simple, fast and efficient it is omitted from current textbooks. This method has several advantages over Siwoloboff such as high reproducibility and direct measurement of the boiling point of the sample obtained by observing the temperature of the vapor-liquid equilibrium. The experiments were performed in the organic chemistry laboratory but allow interdisciplinary integration with other disciplines of several academic areas.

Interactions of chitosan/genipin hydrogels during drug delivery: a QSPR approach

A hydrogel comprised of chitosan crosslinked using the low-toxicity crosslinker genipin was prepared, and the absorption of glibenclamide by the hydrogel was investigated. Optimized structures and their molecular electrostatic potentials were calculated using the AM1 method, and the results were used to evaluate the molecular interactions between the three compounds. The quantitative structure-property relationship model was also used to estimate the activity of the chemicals on the basis their molecular structures. In addition, theoretical Fourier transform infrared spectra were calculated to analyze the intermolecular interactions in the proposed system. Finally, the hydrophilicity of the hydrogel and its influence on the absorption process were also estimated.

DISTRIBUIÇÃO E FRACIONAMENTO DO Hg EM SEDIMENTOS DO RIO PARAÍBA DO SUL – RJ, BRASIL

Mercury distribution and fractionation were determined in sediments from the Paraíba do Sul River – RJ, Brazil. Total mercury concentration ranged from 1 to 158 ng g-1. Hg associated with the weakly bound fraction was dominant in the estuarine areas (main - 60% and secondary - 55%); followed by fluvial end member (48%) and mangrove (18%). These results reinforce the mercury availability to fluvial and estuarine areas and emphasize the key role played by mangroves as an efficient biogeochemical barrier. In conclusion, the continuous reduction of the mangrove ecosystem around the world can exacerbate the damage resulting from the mercury accumulation.

Effects of global climate changes on geographical distribution patterns of economically important plant species in cerrado

Different climate models, modeling methods and carbon emission scenarios were used in this paper to evaluate the effects of future climate changes on geographical distribution of species of economic and cultural importance across the Cerrado biome. As the results of several studies have shown, there are still many uncertainties associated with these projections, although bioclimatic models are still widely used and effective method to evaluate the consequences for biodiversity of these climate changes. In this article, it was found that 90% of these uncertainties are related to methods of modeling, although, regardless of the uncertainties, the results revealed that the studied species will reduce about 78% of their geographic distribution in Cerrado. For an effective work on the conservation of these species, many studies still need to be carried out, although it is already possible to observe that climate change will have a strong influence on the pattern of distribution of these species.

Época de semeadura da soja para a região de Dourados - MS, com base na deficiência hídrica e no fotoperíodo

O objetivo deste trabalho foi definir a época de semeadura da soja para a região de Dourados - MS, em função da deficiência hídrica e do fotoperíodo. Foram avaliadas três épocas de semeadura (15 de outubro, 15 de novembro e 15 de dezembro), utilizando-se de série de 20 anos de dados. A deficiência hídrica da soja foi estimada por meio de balanço hídrico-climatológico diário sequencial, e o fotoperíodo foi calculado em função da latitude e da data. O atraso da semeadura reduziu o déficit hídrico. Analisando-se conjuntamente os fatores déficit hídrico e fotoperíodo, concluiu-se que semeaduras da soja em novembro são mais indicadas para a região de Dourados.

Considerações sobre o tratamento cirúrgico do melanoma maligno anorretal

São analisados os resultados do tratamento cirúrgico em cinco casos de melanoma maligno anorretal (MMAR). Um paciente encontrava-se no estádio clínico I, dois no estádio clínico II e dois no estádio III. Todos os pacientes foram operados, sendo quatro submetidos a excisão local do tumor, e um a amputação abdômino-perineal do reto. Este último sobreviveu por apenas sete meses, enquanto uma paciente, estádio clínico II e submetida apenas à excisão local, sobreviveu por 168 meses. Os autores questionam a validade do estadiamento clínico I (tumores localizados) como fator prognóstico, já que desconsidera o grau de penetração do tumor na parede anorretal. Sugerem ainda a realização de estudos multicêntricos, para que se possa estabelecer uma uniformidade terapêutica para o MMAR.

Tumores malignos do intestino delgado

Os tumores do intestino delgado são raros e a maioria das lesões neoplásicas sintomáticas é maligna.Os neoplasmas benignos são um pouco mais freqüentes e ambos estão relacionados a um diagnóstico difícil, pois determinam queixas abdominais inespecíficas, comuns a uma grande variedade de afecções digestivas. Exames de imagem e endoscópicos podem ser úteis para o diagnóstico, mas freqüentemente não são conclusivos. Para os blastomas primários, a ressecção cirúrgica é a opção de escolha, porém, para os metastáticos, a terapêutica operatória deve ser reservada para os casos complicados por obstrução, hemorragia ou perfuração. O presente estudo tem por finalidade analisar retrospectivamente 13 casos de lesões malignas do intestino delgado, num período de 28 anos. Verificou-se maior incidência de tumores primários (69,2%) e de linfomas (30,7%). Entre os secundários, as mestástases por adenocarcinoma foram as mais freqüentes (15,4%). Enterectomia segmentar foi o procedimento cirúrgico mais realizado (84,6%) e a mortalidade hospitalar foi de 15,4%. A sobrevida de cinco anos foi nula para os pacientes portadores de metástases, enquanto que para os primários foi de 44,4%, sugerindo um melhor prognóstico para as neoplasias primitivas, independentemente do tipo histológico da neoplasia.

Hérnia diafragmática traumática crônica e fístula gastropleurocutânea

Traumatic diaphragmatic hernia is defined as a laceration of the diaphragm with an abdominal viscera herniation into the thorax. It is usually asymptomatic, with the exception of the cases with obstruction, strangulation, necrosis or perforation of the herniaded viscera. It is classified as acute, latent or chronic, in accordance with the evolutive period. At the latent phase, symptoms are indefinite and the radiological signals, which are suggestive of thoracic affections, are frequent and can induce a diagnosis error, leading to inadequate treatment.This article presents a case of chronic traumatic diaphragmatic hernia which was complicated by a gastricpleuralcutaneous fistula, due to an inadequate thoracic drainage. Considering that this is a chronic affection with an unquestionable surgical indication, due to the complications risk, it is essential to have a detailed diagnostic investigation, which aims at both avoiding an intempestive or inadequate therapeutics behaviour and reducing the affection morbimortality. Recently, the videolaparoscopic approach has proved to be more precise when compared to the other diagnostic methods, by direct visualization of the diaphragmatic laceration, allowing its correction by an immediate suture.

Tumor carcinóide do reto

The rectum is the second most common location of the carcinoid tumors of the gastrointestinal tract. It represents approximately one or two per cent of the rectal neoplasms. Metastases are less frequent and it presents a better prognosis than carcinoid tumors found in the digestive tract. Treatment is surgical and the technique to be used depends fundamentally on the size of the tumor and the degree of in the intestinal wall penetration. Lesions which are greater than one centimeter have been treated with local excision, while the ones greater than two centimeters have been submitted to a radical resection. This article presents a case of rectal carcinoid diagnosed and treated initially as adenocarcinoma by abdominal rectossigmoidectomy. There were no signs of recurrence after a period of five years and six months of post-surgical follow-up. Nowadays the validity of radical resection in the treatment of rectal carcinoids has been much questioned due to the fact that it has not shown a significant raise in survival rate when compared with patients who were submitted to a local resection.

Cirurgia de resgate no carcinoma de canal anal

OBJETIVOS: Avaliar a sobrevida dos pacientes portadores de carcinoma epidermóide do canal anal submetidos a cirurgia de resgate, por recidiva ou falha do tratamento radioquimioterápico inicial. MÉTODO: Análise retrospectiva dos pacientes portadores de carcinoma epídermóide do canal anal submetidos a cirurgia de resgate, de outubro de 1986 a setembro de 2000. RESULTADOS: Foram matriculados 93 pacientes portadores de carcinoma epidermóide do canal anal no período, e 21 (22,5%) foram submetidos a resgate cirúrgico. Em 19 pacientes (91%) foi realizada amputação abdominoperineal do reto (operação de Miles), em um paciente exenteração pélvica total e em um paciente excisão local. Não houve mortalidade operatória. A sobrevida média do grupo após resgate cirúrgico foi de 24 meses. CONCLUSÕES: Após recidiva e/ou falha da radioquimioterapia, a cirurgia de resgate é importante no controle locorregional do carcinoma epidermóide do canal anal.