Aspects of the development of clinical chemistry and laboratory medicine in the former East Germany.

Clinical chemistry and laboratory medicine developed rapidly in the industrialised world after the Second World War, as evidenced by the recruitment of physicians and natural scientists, the intensive development of methods and technologies, the founding of societies such as the IFCC, and the organisation of scientific life. In East Germany a working group of clinical pathologists and chemists came together in 1960, out of which grew the Gesellschaft für Klinische Chemie und Laboratoriumsdiagnostik (Society for Clinical Chemistry and Laboratory Diagnostics) in 1968. Within the socialist health care system laboratory services were structured in a pyramid form based on the country's governmental districts. Each local diagnostic laboratory was part of a hierarchy; tests not possible in local laboratories were performed in larger ones. Groups of experts prescribed standardised methods and recommendations of quality control were administered at the district level. However, the funding of this quite acceptable structure was insufficient, resulting in difficulties. Although the development of equipment was carried out in close cooperation with users, it was hindered by shortages extant in the socialist economy. Postgraduate training of physicians, natural scientists, technicians and laboratory assistants was well organised, and clinical chemistry and pathobiochemistry were well established in the medical curriculum.

Semiconductor photocatalysis type B: synthesis of unsaturated alpha-amino esters from imines and olefins photocatalyzed by silica-supported cadmium sulfide.

Novel unsaturated N-phenyl-alpha-amino esters were synthesized in isolated yields of 50 to 10% by visible light irradiation of methanolic suspensions of silica-supported cadmium sulfide in the presence of methyl (2Z)-phenyl(phenylimino)acetate and various cyclic olefins. A semiconductor photocatalysis mechanism is proposed for this linear addition reaction. The light-generated electron-hole pair in the oxidative step induces a dissociative electron transfer from the olefin to CdS affording a proton and an allylic radical, whereas in the reductive step an alpha-aminobenzyl radical is formed in a proton coupled reaction. Heterocoupling of these intermediate radicals leads to the corresponding addition products. As the only by-product the hydrogenated imine is obtained in comparable amounts through the subsequent photoreduction of the alpha-aminobenzyl radical. Supporting the catalyst on silica made the reaction three times faster as compared to neat CdS. When the surface OH groups of CdS were removed through alkylation, the reaction between ArCH=NAr (Ar = p-C1C6H4) and cyclopentene was completely inhibited, but occurred again upon replacing the aldimine by its hydrochloride salt. This indicates that the protonated aldimine is involved in the reductive reaction step. Protonation makes this reduction easier by 0.1 V as indicated by the shift of the reduction potential of methyl (2Z)-phenyl(phenylimino)acetate upon addition of glacial acetic acid to the acetonitrile solution.

Modified, Amorphous Titania-A Hybrid Semiconductor for Detoxification and Current Generation by Visible Light.

Amorphous, microporous TiO2 hybrid semiconductors modified with transition metals induce generation of a photocurrent and photocatalytic degradation of the water contaminant 4-chlorophenol through photoinduced charge separation (the postulated mechanism is shown in the picture, Ar=4-ClC6 H4 ). In contrast to the previously known crystalline titania photocatalysts, which are active only when excited with UV light, the amorphous semiconductors modified with platinum, rhodium, and gold chloride enable both processes also with visible light.