Toxoplasma gondii seropositivity and suicide rates in women

Toxoplasma gondii (T. gondii) is an intracellular protozoan parasite that infects roughly a third of the world population. In an immunocompetent host, infection is generally chronic and asymptomatic, as the immune system keeps T. gondii confined to cysts and the intracellular space within the muscle and brain. Seropositivity has been linked to schizophrenia, car accidents, changes in personality, and more recently, suicidal attempts. Very recently, seroprevalence for 20 European countries was found to be associated with increased suicide rates. Although suicide rates were age-standardized, given that T. gondii seroprevalence increases with age and that the blood samples were drawn in women, we now retested in women only the association between suicide and T. gondii seropositivity, stratified by age. Simple correlations between ranked T. gondii seropositivity and suicide rate identified statistically significant relationships in women 60 years or older (p < 0.05); adjusting for GDP, the statistical significance expanded to include women 45 years and older. The strongest association was in the 60- to 74-year-old group where, after adjustment for GDP, the relationship (p = 0.007) resisted Bonferroni adjustment for multiple comparisons. In conclusion, the results suggest that a positive relationship between rates of infection with T. gondii and suicide is apparent in women of postmenopausal age. Prospective studies are necessary to further confirm this association predictively and to explore mechanisms mediating this relationship.     

European consensus on a competency-based virtual reality training program for basic endoscopic surgical psychomotor skills

Background  

Virtual reality (VR) simulators have been demonstrated to improve basic psychomotor skills in endoscopic surgery. The exercise configuration settings used for validation in studies published so far are default settings or are based on the personal choice of the tutors. The purpose of this study was to establish consensus on exercise configurations and on a validated training program for a virtual reality simulator, based on the experience of international experts to set criterion levels to construct a proficiency-based training program.     

��No scar�� small bowel resection in a survival porcine model using transcolonic NOTES? and transabdominal approach

Background  

Fundamental techniques and essential tools for performing “no scar” surgery still need to be developed. Our study was designed to evaluate the feasibility of performing small bowel resection by transcolonic NOTES^? and transabdominal approach using rigid laparoscopic and flexible endoscopic instruments.     

A model for shrinkage strain in photo polymerization of dental composites.

OBJECTIVES: We formulate a new model for the shrinkage strain developed during photo polymerization in dental composites. The model is based on the diffusion type fractional order equation, since it has been proved that polymerization reaction is diffusion controlled (Atai M, Watts DC. A new kinetic model for the photo polymerization shrinkage-strain of dental composites and resin-monomers. Dent Mater 2006;22:785-91). Our model strongly confirms the observation by Atai and Watts (see reference details above) and their experimental results. The shrinkage strain is modeled by a nonlinear differential equation in (see reference details above) and that equation must be solved numerically. In our approach, we use the linear fractional order differential equation to describe the strain rate due to photo polymerization. This equation is solved exactly. RESULTS: As shrinkage is a consequence of the polymerization reaction and polymerization reaction is diffusion controlled, we postulate that shrinkage strain rate is described by a diffusion type equation. We find explicit form of solution to this equation and determine the strain in the resin monomers. Also by using equations of linear viscoelasticity, we determine stresses in the polymer due to the shrinkage. The time evolution of stresses implies that the maximal stresses are developed at the very beginning of the polymerization process. SIGNIFICANCE: The stress in a dental composite that is light treated has the largest value short time after the treatment starts. The strain settles at the constant value in the time of about 100s (for the cases treated in Atai and Watts). From the model developed here, the shrinkage strain of dental composites and resin monomers is analytically determined. The maximal value of stresses is important, since this value must be smaller than the adhesive bond strength at cavo-restoration interface. The maximum stress determined here depends on the diffusivity coefficient. Since diffusivity coefficient increases as polymerization proceeds, it follows that the periods of light treatments should be shorter at the beginning of the treatment and longer at the end of the treatment, with dark interval between the initial low intensity and following high intensity curing. This is because at the end of polymerization the stress relaxation cannot take place.