Characterization of Ascaris from Ecuador and Zanzibar

To shed light on the epidemiology of ascariasis in Ecuador and Zanzibar, 177 adult worms retrieved by chemo-expulsion from either people or pigs were collected, measured and subjected to polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis of the ribosomal internal transcribed spacer (ITS) region. Upon double digestion with RsaI and HaeIII, PCR-RFLP analysis revealed the presence of A. lumbricoides in people and A. suum in pigs in Ecuador. In contrast, while there are no pigs on Zanzibar, of the 56 worms obtained from people, one was genotyped as A. suum. No additional genetic variation was detected upon further PCR-RFLP analysis with several other restriction enzymes. Upon measurement, worm mass and length differed by location and by species, A. suum being lighter and longer. While there is no evidence to suggest zoonotic transmission in Ecuador, an enduring historical signature of previous zoonotic transmission remains on Zanzibar

Use of synchrotron tomographic techniques in the assessment of diffusion parameters for solute transport in groundwater flow

This technical note describes the use of time-resolved synchrotron radiation tomographic energy dispersive diffraction imaging (TEDDI) and tomographic X-ray fluorescence (TXRF) for examining ion diffusion in porous media. The technique is capable of tracking the diffusion of several ion species simultaneously. This is illustrated by results which compare the movement of Cs+, Ba2+ and La3+ ions from solution into a typical sample of English chalk. The results exhibited somewhat anomalous (non-Fickian) behaviour and revealed heterogeneities (in 1D) on the scale of a few millimetres

Doctors and the war against tobacco

published_or_final_versio

Regulation of cell-cell adhesion in keratinocytes: The reciprocal relationship between cadherins and Rho family GTPases

Cadherins are transmembrane receptors, which mediate adhesion between adjacent cells. They play an essential role in development and maintenance of tissue architecture. The RHO GTPases modulate actin cytoskeletal architecture in different cell types. Two family members in particular, RhoA and Rad, have been found to regulate the stability of cadherin receptors at intercellular junctions. In this thesis I set out to study in more detail the relationship between cadherin-mediated adhesion and the small GTPase Rac in keratinocytes. Previous work has shown that while Rac is necessary for cell-cell contact formation, it can also disrupt cadherin-dependent adhesion when its activity is sustained. I have mapped the domain of Rac that is required for breakdown of intercellular junctions. In addition, I have shown that Rac mediates perturbation of cell-cell adhesion induced by oncogenic H-Ras. I have also investigated which Rac effectors may mediate Rac-induced disassembly of cell-cell contacts. To look for new Rac targets that may regulate cadherin-mediated adhesion, I performed a yeast two-hybrid screen of a keratinocyte library and identified a novel Rac-binding clone. Ligand binding to a variety of cell surface receptors has been found to induce Rac activation. I have found that calcium-induced cell-cell contact formation can also activate Rac. Cadherin function is necessary for Rac activation, and clustering of the cadherin receptors is sufficient to activate Rac. Initial activation of Rac is dependent on signalling from the EGF receptor but not PI 3-kinase activity. At later time-points, Rac is activated by an alternative EGF-receptor-independent mechanism. In conclusion, this work focuses on the relationship between Rac and cadherin-mediated adhesion in epithelia. This could shed light on the regulation of epithelial morphogenesis under normal conditions and potentially lead to an understanding of how this is subverted during tumorigenesis

Comparison of Fish and Benthic Faunal Compositions in Polluted and Pristine Forks of a Mountain River

The little Pigeon River in Sevier County, Tennessee presents a near ideal situation for the study of the effects of domestic sewage on species composition in a mountain river. The little Pigeon system has two principal components, the West and Middle Prongs. The West Prong is polluted by municipal effluent from Gatlinburg and Pigeon Forge, while the Middle Prong remains relatively pristine. Physicgraphically, the two prongs are strikingly similar. The great similarity of natural physical and chemical water quality parameters presents an opportunity to use the pristine prong as a control for the study of changes, probably resulting from pollution, in the other. Fish and aquatic invertebrates were sampled from riffle communities of both streams, and their composition was analyzed to gain insight into possible changes in the West Prong due to pollution. There were drastic differences in benthic invertebrates and observable differences in the fish faunal assemblages. These differences suggest that strong shifts in species composition as well as a sharp decline in population density of many invertebrates and some fish species had resulted in the West Prong due to pollution. It is speculated that these shifts were caused by organic solids

The role of the GP in helping patients stop smoking

published_or_final_versio

Optimal Class Size, Opt-Out Rights, and Indivisible Remedies

Prepared for a Symposium on the ALI’s Aggregate Litigation Project, this paper examines the ALI’s proposal to permit opt-out rights when remedies and “divisible,” but not to permit them when remedies are “indivisible.” Starting from the ground up, the paper employs economic analysis to determine what the optimal size of a class action should be. We demonstrate that, in some circumstances, the optimal size of a class is a class composed of all victims, while in other cases, the optimal size is smaller. We further argue that courts should consider optimal class size in determining whether to certify a class, and that there should be no opt-out right when a class is optimally sized. The ALI’s approach does not always lead to the most efficiently sized class actions

Non-medical mental health referrals: a guide for general practice

The results of part of a survey of mental health practitioners in Hong Kong are discussed with reference to similarities and differences in roles, definitions, education, training and professional regulation in their countries of origin. The need for more monitoring and regulation of non-medical mental health practitioners is considered in light of the concerns of general practitioners who want to make suitable referrals.published_or_final_versio