Bi-component semiconductor oxide photoanodes for the photoelectrocatalytic oxidation of organic solutes and vapours: a short review with emphasis to TiO2-WO3 photoanodes.

The use of binary semiconductor oxide anodes for the photoelectrocatalytic oxidation of organic species (both in solution and gas phase) is reviewed. In the first part of the review, the principle of electrically assisted photocatalysis is presented, the preparation methods for the most common semiconductor oxide catalysts are briefly mentioned, while the advantages of appropriately chosen semiconductor combinations for efficient UV and visible (vis) light utilization are highlighted. The second part of the review focuses on the discussion of TiO(2)-WO(3) photoanodes (among the most studied bi-component semiconductor oxide systems) and in particular on coatings prepared by electrodeposition/electrosynthesis or powder mixtures (the focus of the authors' research during recent years). Studies concerning the microscopic, spectroscopic and photoelectrochemical characterization of the catalysts are presented and examples of photoanode activity towards typical dissolved organic contaminants as well as organic vapours are given. Particular emphasis is paid to: (a) The dependence of photoactivity on catalyst morphology and composition and (b) the possibility of carrying out photoelectrochemistry in all-solid cells, thus opening up the opportunity for photoelectrocatalytic air treatment.

Diphtheria outbreak in St. Petersburg: clinical characteristics of 1860 adult patients.

An epidemic of respiratory tract diphtheria began in Russia in 1989. In 1994 more than 2,500 cases occurred in St. Petersburg alone. We describe clinical findings in the 1,860 adult patients treated in Botkin's Hospital. The study is based on a retrospective review of patient records. In 98% of the patients the diagnosis was confirmed by a positive throat culture growing a toxin producing strain of Corynebacterium diphtheriae. A catarrhal disease without membranes was present in 1,256 (67.5%) patients, 150 patients had membranes on tonsils only, 268 patients on tonsils, the uvula, soft palate and posterior pharynx and 35 patients on larynx or in the lower respiratory tract. 42 patients (2.3%) died. Among the deceased patients 26 were alcoholics, whereby the death rate for non-alcoholics was probably around 1%. 151 patients (8.1%) had a toxic form of the disease with swelling of the neck. This form of the disease carried a high mortality, 25.7%. In a subgroup of 1,045 patients the protective efficacy of vaccination could be evaluated. A 2.2-fold protection was found, but the study may underestimate the efficacy. We conclude, that if a wide diphtheria epidemic affects an industrialized country, it would probably not any more be the big killer that it was in Europe and in the United States in the 1950's and 1960's.