Numerical method to digital photoelasticity using plane polariscope

This research aims to find a new way to get the intensity equations for the phase-shifting model in digital photoelasticity. The procedure is based on the rotation of the analyzer itself. From the intensity equations, the isoclinic and isochromatic equations parameters are deduced by applying a new numerical technique. This approach can be done to calculate how many images allow the resolution of the polariscope. Each image indicates the stress forces in the object. In this study the plane polariscope was used. The amount of images will determinate the number of errors and uncertainties of the study, due to the observation that the veracity of the equations increases considerably with a large amout of images. Several analyses are performed with different amounts of photographic images. The results showed the possibility to measure stress forces with high precision using plane polariscopes.

Leptin in Alzheimer's disease

Alzheimer's disease (AD) is the most common cause of progressive dementia in the elderly population. AD is histologically characterized by accumulation of amyloid-β protein (Aβ) on extracellular plaques and deposition of hyperphosphorylated tau protein in intracellular neurofibrillary tangles. Several studies have shown that obesity may precede dementia and that lifestyle factors play a critical role in the onset of AD. Furthermore, accumulating evidence indicates that obesity is an independent risk factor for developing AD. In this scenario, the understanding of the role of adipose tissue in brain health is essential to clarify the establishment of demential processes. The objective of this work was to review studies regarding leptin, an anorexigenic peptide hormone synthesized in adipocytes, in the context of dementia. Some authors proposed that leptin evaluation might be a better predictor of dementia than traditional anthropometric measures. Leptin, once established as a biomarker, could enhance the understanding of late-onset AD risk over the life course, as well as the clinical progression of prodromal state to manifested AD. Other studies have proposed that leptin presents neuroprotective activities, which could be explained by inhibiting the amyloidogenic process, reducing the levels of tau protein phosphorylation and improving the cognitive function.

PCBs, PBDEs and organochlorine pesticides in crabs Hepatus pudibundus and Callinectes danae from Santos Bay, State of São Paulo, Brazil

The occurrence of persistent organic pollutants (POPs) as polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs) and polybrominated diphenyl ethers (PBDE) in crabs Hepatus pudibundus and Callinectesdanae was assessed from two different places inside of the Santos Bay and Moela Island near one of the most economically important metropolitan areas in Southern Brazil. Among POPs analyzed, ∑PCBs (222-923 ng g(-1)lipid weight) and ∑DDTs (154-410 ng g(-1)lw) exhibited the highest concentrations in the crabs. ∑HCHs ranged from 10.3 to 30.9 ng g(-1)lw and were found in all individuals. Other OCPs found in lower concentration was Mirex (7.6-41.6 ng g(-1)lw) and HCB (5.83-16.9 ng g(-1)lw). ∑PBDEs (24.1 ng g(-1)lw) were only found in one male individual from the species C. danae collected near to the submarine sewage of Santos. Male crabs showed higher POP concentrations than female crabs for those two species.

Identification of enteropathogenic and enterohaemorrhagic Escherichia coli strains by immunoserological detection of intimin

AIMS

To evaluate the sensitivity and specificity of polyclonal and monoclonal antibodies (Mabs) against intimin in the detection of enteropathogenic and enterohaemorrhagic Escherichia coli isolates using immunoblotting.

METHODS AND RESULTS

Polyclonal and Mabs against the intimin-conserved region were raised, and their reactivities were compared in enteropathogenic E. coli (EPEC) and enterohaemorrhagic E. coli (EHEC) isolates using immunoblotting analysis. In comparison with rat antiserum, rabbit anti-intimin IgG-enriched fraction had a stronger recognition pattern to a wide spectrum of intimin types in different EPEC and EHEC serotypes. On the other hand, murine monoclonal IgG2b specific to intimin, with dissociation constant of 1.3x10(-8) mol l(-1), failed in the detection of some of these isolates.

CONCLUSION

All employed antibodies showed 100% specificity, not reacting with any of the eae-negative isolates. The sensitivity range was according to the employed antisera, and 97% for rabbit anti-intimin IgG-enriched fraction, followed by 92% and 78% sensitivity with rat antisera and Mab.

SIGNIFICANCE AND IMPACT OF THE STUDY

The rabbit anti-intimin IgG-enriched fraction in immunoblotting analysis is a useful tool for EPEC and EHEC diagnoses.