Steric and polar effects in free-radical reactions. - An unusual type of azocoupling by free radical decomposition of diazonium salts

A new free-radical azocoupling has been accomplished by decomposition of diazonium salts with monoelectronic reducing agents in the presence of 4-methyl-3-penten-2-one. Steric and polar factors are responsible of the unusual behaviour. © 1980

Crystal structure and packing analysis of the liquid crystal dimer alpha, omega - bis(4-cyanobiphenyl-4'-yloxy)octane

The crystal structure of the liquid crystal dimer alpha,omega -bis(4-cyanobiphenyl-4'-yloxy)octane has been determined from diffraction data obtained with synchrotron radiation. The structure is triclinic, with the space group P-1 with Z = 2 and the unit cell parameters are a = 7.135(5) Angstrom, b = 12.811(5) Angstrom, c = 15.639(5) Angstrom, alpha = 75.800(5)degrees, beta = 84.690(5)degrees, gamma = 77.930(5)degrees. The flexible spacer linking the mesogenic groups is in the all-trans-conformation. Although the molecule has a potential centre of symmetry, it occupies a general position in the cell; this unusual behaviour has been investigated with the aid of a theoretical evaluation of the packing energy

Sintering and characterisation of ceramics containing paper sludge, glass cullet and different types of clayey materials

The present paper reports on the sintering behaviour of several ceramics prepared using a previously selected mixture of incinerated paper mill sludge and glass cullet in the ratio 60/40 which was blended with 10, 20, 30 and 40 wt.% of three different natural materials. The three natural products were: a red quartzitic clay, a yellow quartzitic clay and a kaolin. All mixtures were blended by attrition milling and dried; powders were sieved, pressed into specimens and fired for 1 h at temperatures ranging from 1040 to 1140 \ub0C. The resulting materials were characterized by water absorption, shrinkage, crystallographic composition, microstructure and physico-mechanical properties. It was observed that materials containing kaolin display the best overall behaviour independently of the quantity of kaolin introduced. Conversely the optimal sintering temperature, and consequently the best properties of the materials prepared using red or yellow clay were measured on products fired at temperatures above 1080 \ub0C; materials and temperatures are affected by the amount of clay adde

Metástase de câncer gástrico simulando neoplasia primária de pulmão: relato de caso e revisão da literatura Gastric cancer metastasis mimicking primary lung cancer: case report and review of the literature

O adenocarcinoma gástrico apresenta, freqüentemente, disseminação por extensão direta para órgãos vizinhos. Metástases para sítios distantes, como o pulmão, são menos freqüentes, sugerindo usualmente outras doenças. O objetivo deste artigo é apresentar o caso de um paciente de 47 anos de idade, cujos exames de imagem (radiografias simples e tomografia computadorizada de tórax) apresentaram características sugestivas de neoplasia pulmonar primária e com diagnóstico simultâneo de câncer gástrico evidenciado pela endoscopia digestiva alta. A biópsia, guiada por fibrobroncoscopia, da massa torácica confirmou o diagnóstico de metástase pulmonar de adenocarcinoma gástrico. Além da apresentação do caso, é feita uma revisão do padrão de disseminação do câncer gástrico.<br>Gastric cancer frequently presents intraperitoneal spread. Distant metastases are rare. The authors describe a case of a 47-year-old white man, long-term cigarette smoker, who had a right upper lobe mass seen on plain films and computed tomography of the chest. A gastric adenocarcinoma was concomitantly diagnosed by endoscopic examination. A bronchoscopy guided biopsy showed that the lung mass was in fact a metastasis from gastric adenocarcinoma. In this article, the imaging findings of gastric cancer and the patterns of dissemination to other organs are reviewed