Characterization of Mullite Ceramic Membranes and their Application in the Removal Escherichia Coli

This paper aims the morphological and structural characterization of ceramic membranes of mullite and their application in the removal of Escherichia coli. A complex irregular structure presented by the pores of the membrane was verified by scanning electron microscopy (SEM). The average pore size and distribution were determined by mercury intrusion porosimetry. The average pore size of the material presented was 0,39 μm. Microfiltration tests resulted in a protein retention of 46, 76 and 89% for trypsin (TR), egg albumin (EA) and bovine serum albumin (BSA), proving the efficiency of the membrane microfiltration tests for molecular weight of 69 kDa. The application of the membranes on the retention of gram-negative bacterium E. coli resulted in a 66% efficiency at a pressure of 200 kPa and a 98% efficiency when applied a pressure of 50 kPa. Therefore, the use of mullite membranes show limited efficiency towards bacteria retention. Nevertheless, they present fluxes similar to other materials proposed in the literature

Alzheimer disease models and human neuropathology: similarities and differences

Animal models aim to replicate the symptoms, the lesions or the cause(s) of Alzheimer disease. Numerous mouse transgenic lines have now succeeded in partially reproducing its lesions: the extracellular deposits of Aβ peptide and the intracellular accumulation of tau protein. Mutated human APP transgenes result in the deposition of Aβ peptide, similar but not identical to the Aβ peptide of human senile plaque. Amyloid angiopathy is common. Besides the deposition of Aβ, axon dystrophy and alteration of dendrites have been observed. All of the mutations cause an increase in Aβ 42 levels, except for the Arctic mutation, which alters the Aβ sequence itself. Overexpressing wild-type APP alone (as in the murine models of human trisomy 21) causes no Aβ deposition in most mouse lines. Doubly (APP × mutated PS1) transgenic mice develop the lesions earlier. Transgenic mice in which BACE1 has been knocked out or overexpressed have been produced, as well as lines with altered expression of neprilysin, the main degrading enzyme of Aβ. The APP transgenic mice have raised new questions concerning the mechanisms of neuronal loss, the accumulation of Aβ in the cell body of the neurons, inflammation and gliosis, and the dendritic alterations. They have allowed some insight to be gained into the kinetics of the changes. The connection between the symptoms, the lesions and the increase in Aβ oligomers has been found to be difficult to unravel. Neurofibrillary tangles are only found in mouse lines that overexpress mutated tau or human tau on a murine tau −/− background. A triply transgenic model (mutated APP, PS1 and tau) recapitulates the alterations seen in AD but its physiological relevance may be discussed. A number of modulators of Aβ or of tau accumulation have been tested. A transgenic model may be analyzed at three levels at least (symptoms, lesions, cause of the disease), and a reading key is proposed to summarize this analysis

Spectroscopic and theoretical studies of some 2-substituted N-methoxy-N-methyl-amides

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)B3LYP/6-311++G(3df,3pd) calculations along with the NBO analysis of some 2-substituted N-methoxy-N-methyl-amides Y-C(R)(2)C(O)N(OMe)Me [Y = Br 1, SEt 2, SePh 4 (for R = H) and SEt 3 (for R = Me)] indicated the existence of three conformers for 1, 2, 4, namely one cis (c) and two gauche (g(1), g(2)), and two gauche (g(1), g(2)) forms for 3. The g(1) conformer is the most stable and the least polar for all derivatives, while the c one is the most polar for 1, 2 and 4. As far as the stability is concerned, the g(2) conformer is more abundant with respect to the c one for compounds 1 and 2, and slightly less stable than c for 4. For the derivative 3, the g(1) conformer is more stable and slightly less polar than the g(2) one. Moreover, the computed (nu(co)) frequencies and the relative populations of the two forms correlate quite well with the IR (nu(co)) doublet frequency components and their relative intensities in solution. The occurrence of Fermi resonance in the fundamental nu(co) region, in solution, precludes the estimative of the relative populations of the c, g(1), g(2) conformers for 1, 2 and 4. NBO analysis showed that the n(N) -> pi(center dot)(co) orbital interaction is the main factor which stabilizes the gauche (g(1), g(2)) conformers into a larger extent relative to the cis (c) one for 1, 2, 4. For these compounds along with the 3 derivative, the same interaction stabilizes more the g(1) conformer than the g(2) one. The sum of the orbital interactions from NBO analysis and the trend of the electrostatic interactions justifies quite well the populations of the (c) and gauche (g(1), g(2)) conformers for 1, 2 and 4, along with the (g(1), g(2)) conformers populations for 3 found in the gas phase. (C) 2012 Elsevier B.V. All rights reserved.103191103Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)MIURFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Ocular tuberculosis misdiagnosed as retinoblastoma: an interesting case

Tuberculosis is a ubiquitous disease and a public health problem of major importance in almost all developing and underdeveloped countries. It can involve any part of the body, including the eye. We report a case of a young child presenting with a painful blind eye with leucocoria, where a misdiagnosis of retinoblastoma was made clinically. The eye was enucleated, and subsequent pathological examination led to a final diagnosis of ocular tuberculosis. The patient was put on anti-tubercular treatment, and responded well

Soluble tumour necrosis factor (TNF)-receptor levels in serum as markers of anti-viral host reactivity

The role of soluble receptors for TNF-α (sTNF-Rs) as markers of virus-induced host responses was studied by the use of murine model infections. A marked elevation in serum levels of sTNF-R75, but not sTNF-R55, was found 1 day after infection with vesicular stomatitis virus (VSV). In mice infected with lymphocytic choriomeningitis virus (LCMV), an early increase was also revealed, but peak levels of sTNF-R75 were observed later temporally related to maximal T cell-mediated anti-viral activity. Analysing different well characterized knockout mice, it was found that elevated release of sTNF-R75 into serum early after VSV infection was independent of T cells, whereas interferon (IFN)-α/β seemed to be a major mediator. In contrast, increased release of sTNF-R75 into serum 8 days post-LCMV infection was mediated via T cells but independently of both CD40 ligand and IFN-γ. A simple correlation between release of sTNF-Rs in vivo and macrophage activation in vitro was not present. These findings indicate that sTNF-R75 is indeed a sensitive marker of both innate and specific cell-mediated host reactivity during viral infection, but it is not correlated to a single immunological parameter