Studies in char gasification—III: The combustion zone

The fluidized bed steam-oxygen-char gasifier is modelled by treating the bed as one in which the solids are well mixed and the gases are in plug flow. This model permits a detailed analysis of the combustion zone. The entire reactor is assumed to be at a uniform temperature. From the results of the model calculations, it was concluded that the assumption of negligible combustion zone thickness made in the earlier two papers is acceptable This model predicts higher total carbon conversion and methane mole fraction in the product gas than the lumped model analysed in an earlier paper.     

Acute respiratory response to prolonged, moderate levels of sidestream tobacco smoke

Carefully controlled, clinical research has shown psychiatric rehabilitation to significantly help persons with severe mental illness address their disabilities and obtain a higher quality of life. For psychiatric rehabilitation to yield its greatest effect, discrete principles and skills that are part of the rehabilitation paradigm must be disseminated to staff working in real-world settings. Staff training strategies that help the rehabilitation team develop effective programs are especially important. This paper reviews Interactive Staff Training (IST), an approach to team building and program development that combines educational and organizational strategies. IST comprises four stages--introduction to the system, program development, program implementation, and program maintenance--with each stage defined by behavioral tasks that engage the team and corresponding products that serve as markers of progress. Testing treatment dissemination strategies poses interesting problems for the researcher, some which are reviewed here. Outcome studies completed on IST are summarized in light of these problems. The paper ends with a consideration of some future directions for research in this area.     

Evaluation of immunoglobulin A1 (IgA1) protease and IgA1 protease-inhibitory activity in human female genital infection with Neisseria gonorrhoeae

Immunoglobulin A1 (IgA1) protease, an enzyme that selectively cleaves human IgA1, may be a virulence factor for pathogenic organisms such as Neisseria gonorrhoeae. Host protection from the effects of IgA1 protease includes antibody-mediated inhibition of IgA1 protease activity, and it is believed that the relative balance between IgA1 protease and inhibitory antibodies contributes to the pathogenesis of disease caused by IgA1 protease-producing organisms. We have examined the levels of these two opposing factors in genital tract secretions and sera from women with uncomplicated infection with N. gonorrhoeae. When IgA1 in cervical mucus was examined by Western blotting, no evidence of cleavage fragments characteristic of IgA1 protease activity was seen in gonococcus-infected or control patients. Cleavage fragments typical of IgA1 protease were detected, however, after the addition of exogenous IgA1 protease to cervical mucus. Degraded IgA1 was detected in some vaginal wash samples, but the fragment pattern was not typical of IgA1 protease activity. All N. gonorrhoeae isolates from the infected patients produced IgA1 protease in vitro. All but two serum samples and 16 of 65 cervical mucus samples displayed inhibitory activity against gonococcal IgA1 protease, but there was no significant difference in the level of inhibitory activity between gonococcus-infected and noninfected patients in either cervical mucus or serum. There was no difference in the levels of IgA1 protease-inhibitory activity in serum or cervical mucus collected from patients at recruitment and 2 weeks later. These results suggest that cleavage of IgA1 by gonococcal IgA1 protease within the lumen of the female lower genital tract is unlikely to be a significant factor in the pathogenesis of infections by N. gonorrhoeae.     

Heavy sarcocystosis in the ocular musculature of cattle and buffaloes

A high prevalence of 71.5 per cent and 69.7 per cent of sarcocystosis was observed in the ocular musculature of cattle and buffaloes respectively, in Bihar, India. The concentration of cysts in the eye muscle was also usually heavy. Ocular musculature appears to be a preferred site for the development of Sarcocystis in these intermediate hosts, second only to the heart muscle. The species of Sarcocystis involved in the present study were morphologically indistinguishable from S. cruzi in cattle and S. levinei in buffaloes. This appears to be the first report on the occurrence of S. cruzi and S. levinei in ocular musculature.     

Fatty acids and fatty aldehydes of buffalo seminal plasma and sperm lipid

Analysis of the fatty acids of total and neutral lipids, glycolipids, phospholipids and gangliosides of buffalo spermatozoa and seminal plasma showed that there were high levels of polyunsaturated acids. Neutral lipids were the richest in polyunsaturated acids (55% in spermatozoa and 61% in seminal plasma). The major saturated acid of all the principal classes was stearic acid and the major unsaturated acid was docosahexaenoic acid (22:6omega3) except in the neutral lipids in which it was arachidonic acid (20:4omega6). The major aldehyde was palmitaldehyde (16:0) in buffalo sperm lipids and docosanal (22:0) in seminal plasma. More than 50% of the total aldehydes was contributed by aldehydes with a chain length greater than 18 carbon atoms.     

Mass flux coupling by confined equilibrium reaction

Various physical systems with either phase boundaries or semi-permeable membranes can give rise to a confined chemical reaction. An analysis was performed to show the strong and potentially important effect of this confined reaction on chemical species diffusion through the region of reaction. The reaction was treated as one near equilibrium in order to obtain an analytical solution and to illustrate the strong coupling of fluxes caused by the reaction. Some generalities, e. g., facilitated diffusion of a single species transferring, were deduced using the above conditions and assumptions. These generalities are necessarily valid only for a single near equilibrium reaction with constant diffusivity of non-diffusing species. Three examples were solved to illustrate the strong coupling of mass fluxes.     

Project management and the construction of the Hong Kong mass transit railway

The management structure and systems used by the Hong Kong Mass Transit Railway Corporation to control time and cost during the construction phases of their railway works are described. Some of the factors that contributed to the opening of the first two phases of the project, ahead of programme and under budget, are also discussed.     

The prevalence of asymptomatic urinary-tract infection in pre-school children

Urine samples from 1000 pre-school children aged 4 weeks to 5 years, attending welfare centres, nursery schools or day nurseries in one London borough, were cultured by the dip-slide method. Five children had asymptomatic bacteriuria, a prevalence of 0-5 per cent. The need for screening the urine of pre-school children is discussed.