Resistance of different types of concretes to cyclic sulfuric acid and sodium sulfate attack

An improvement in accelerated testing as a way of predicting durability was proposed in this study. Accordingly, the behavior of different concrete mixtures was examined in relation to a cyclic exposure to sulfuric acid and sodium sulfate solutions, recording the expansion and mass loss of the test specimens for about 5 years. Three different cements – i.e. Portland limestone, blast furnace slag and pozzolanic cement – were used, the latter two both with and without silica fume (SF), to prepare the concretes for the study. Scanning Electron Microscopy (SEM) and energy-dispersive X-ray analysis (EDX) were used to correlate the samples’ microstructure and deformation.The lowest expansion was obtained by mixtures containing silica fume, although they were more susceptible to corrosion in acid. After a dormant period when no expansion occurred, the Portland limestone cement and blast furnace slag cement exhibited a large expansion that began suddenly and increased at an almost constant rate. This expansion correlated with the presence of cracks filled with calcium sulfate crystals in the core of the concrete samples.For comparison, the expansion of concretes specimens left in a sodium sulfate solution was also measured. The dormant period in the two-step expansion process seen in the Portland limestone and blast furnace concretes was shorter in the cyclic testing in sulfate and sulfuric acid, which can be considered as a model of accelerated deterioration, than in the latter.     

Drug resistance patterns among tuberculosis patients in Rome, 1990-1992

PURPOSE: A Phase II study to evaluate the effect of a five-drug regimen, VP-16, ifosfamide, cisplatin, vinblastine, and bleomycin (VIP/VB) on complete response rate, continuous disease-free survival, and toxicity in patients with advanced germ-cell tumor. PATIENTS AND METHODS: Twenty male patients with a histologic diagnosis of advanced-stage germ-cell cancer, previously untreated with chemotherapy, received the following: etoposide 75 mg/m2 i.v. days 1-5; ifosfamide (with mesna uroprotection) 1.2 g/m2 i.v. days 1-5; cisplatin 20 mg/m2 i.v. days 1-5; vinblastine 0.18 mg/kg i.v. day 1; bleomycin 30 units i.v. day 1; filgrastim 5 micrograms/kg days 7-16. Chemotherapy was given every 3 weeks (bleomycin weekly x 12) for four courses. RESULTS: All patients entered were evaluable for toxicity, response, and survival. Eleven of 20 (55%) achieved complete remissions with chemotherapy alone and an additional 5 (25%) were rendered disease-free with surgical resection of teratoma (3) or viable cancer (2). Two patients relapsed at 4 and 5 months from complete remission (CR). There was one treatment-related death, from bleomycin lung toxicity after thoracotomy. Thirteen patients (65%) are alive and continuously free of disease, with a median follow-up of 20 months and a minimal follow-up of 12 months. Hematologic toxicity was most common, with 16 patients (80%) having grade 3 or 4 leukopenia. CONCLUSIONS: VIP/VB appears to be a very active regimen in advanced disseminated germ-cell cancer. Hematological toxicity was severe but manageable.     

AIDS-related knowledge and sex behavior: a review of Italian studies of young people

To plan further AIDS health promotion programmes information is needed about knowledge and attitudes relating to HIV infection among the general public. This article reviews the results of Italian studies conducted from 1990 to 1994 on young's knowledge and behaviour related to HIV infection. Eighteen studies were identified. The results show a good level of knowledge of the means of transmitting the virus, but suggest that the information does not necessarily involve a change in attitude and behaviour.