The Effect of Volume Shape Factor on the Crystal Size Distribution of Fragments due to Attrition

The effect of volume shape factor on crystal size distribution (CSD) is usually ignored to simplify the analysis of population balance equation. In the present work, the CSD of fragments generated from a mechanically stirred crystallizer as the result of attrition mechanism has been reported when the volume shape factor conforms to normal distribution. The physical model of GAHN and MERSMANN which relates the attrition resistance of a crystalline substances to its mechanical properties has been employed. The simulation of fragment size distribution was performed by Monte Carlo (MC) technique. The results are compared with those reported by GAHN and MERSMANN.

Using survey data to explore preschool children’s ethnic awareness and attitudes

This article presents the findings of a large-scale survey (n = 1049) of ethnic awareness and attitudes among three to four-year-old children in Northern Ireland. In drawing upon and applying Bourdieu’s notion of habitus, the article demonstrates how, even at this age, the children are already beginning to embody and internalize the cultural habits and dispositions of their respective ethnic groups; namely the Protestant and Catholic communities. This is illustrated in the present article in relation to the children’s attitudes towards particular national flags and awareness of specific sports associated with their respective communities. Informed by the work of Bourdieu, the article concludes by arguing for the need for greater use of quantitative methods in conjunction with in-depth qualitative and ethnographic research to help further our understanding of the influence of ethnicity in young children’s lives.

ZapA, a virulence factor in a rat model of Proteus mirabilis-induced acute and chronic prostatitis.

Our knowledge of pathogenesis has benefited from a better understanding of the roles of specific virulence factors in disease. To determine the role of the virulence factor ZapA, a 54-kDa metalloproteinase of Proteus mirabilis, in prostatitis, rats were infected with either wild-type (WT) P. mirabilis or its isogenic ZapA- mutant KW360. The WT produced both acute and chronic prostatitis showing the typical histological progressions that are the hallmarks of these diseases. Infection with the ZapA- mutant, however, resulted in reduced levels of acute prostatitis, as determined from lower levels of tissue damage, bacterial colonization, and inflammation. Further, the ZapA- mutant failed to establish a chronic infection, in that bacteria were cleared from the prostate, inflammation was resolved, and tissue was seen to be healing. Clearance from the prostate was not the result of a reduced capacity of the ZapA- mutant to form biofilms in vitro. These finding clearly define ZapA as an important virulence factor in both acute and chronic bacterial prostatitis.