6-thio-GTP Derivatives

Pore structural characteristics of mesostructured materials prepared under different conditions

This paper presents an overview of the pore structural properties of different mesostructured materials prepared at room temperature, namely MCM-41, MCM-48 and MMS. The stability towards water vapour of some samples is inferred by XRD and nitrogen adsorption after and prior to water adsorption. It is shown that MMS materials are more stable than MCM-41. A new method for the stabilisation of MCM-41 using tetraethoxysilane (TEOS) in hexane as silicification agent is proposed and it is shown to be effective in stabilising the pore structure and to increase significantly the surface hydrophobicity.

MCM-41, MCM-48 and related mesoporous adsorbents: their synthesis and characterisation

MCM-41, MCM-48, MCM-41 analogue materials and disordered silica xerogels were compared with respect to their long range and short range order, their specific surface area, pore structure and pore structural parameters, pore wall thickness and their surface hydroxyl group concentration. Based on X-ray diffraction data it could be seen that the degree of long range order decreased in the order MCM-41>MCM-48>MCM-41 analogues >amorphous silica xerogels. The particle porosity and pore wall thickness increased in the same sequence such that MCM-41 analogues and amorphous silica xerogels were more stable towards water and water vapour. The concentration of the surface hydroxyl groups increased whe…

Urolithiasis Following Portacaval Shunt in Rats

A reliable technique for a portacaval anastomosis (PCA) in rats was first published by Lee and Fisher 1961. Since then the biological and biochemical consequences have been studied extensively in numerous investigations. The occurrence of a urolithiasis following PCA was first reported by Herz et al. 1972. Disturbances of uric acid metabolism that were caused by the shunt were thought to be responsible. They should lead to an increased production of endogenous uric acid and thus to hyperuricosuria. Investigations that were published since then mainly focused on chemical stone analysis (Bichler et al. 1974; Rasenack et al. 1977; Wallace et al. 1984).

Development of Bladder Carcinoma Following Portacaval Shunt in Rats

Portacaval anastomosis (PCA) was first introduced by Eck (1877) and was investigated in a number of different animals. Lee et al. (1961; 1974) published a reliable method with low mortality in rats. The occurrence of urolithiasis in rats following portacaval anastomosis happened to be noticed by chance. It was published by Herz et al. (1972a, 1972b, 1973), who defined the portacaval shunt rat as an experimental model. Heine et al. (1979) described dysplastic and neoplastic changes of the bladder mucosa following portacaval anastomosis. His findings were confirmed by Duy et al. (1981); Grun et al. (1982), and Dubuisson et al. (1984). However, Wallace et al. (1984) found papillary hyperplasia…

Hepatitis A-like non-A, non-B hepatitis: light and electron microscopic observations of three cases.

To date, three types of NANBH have been distinguished by epidemiological, clinical and experimental data. We examined the liver biopsies of three patients with an acute NANBH resembling hepatitis A from the infection route, incubation period and clinical course. The liver biopsies revealed lesions with a portal and periportal predominance, thus also exhibiting parallels with hepatitis A on the histopathological level.