Molecular characterisation of congenital myasthenic syndromes in Southern Brazil

Objective To perform genetic testing of patients with congenital myasthenic syndromes (CMS) from the Southern Brazilian state of Parana. Patients and methods Twenty-five CMS patients from 18 independent families were included in the study. Known CMS genes were sequenced and restriction digest for the mutation RAPSN p.N88K was performed in all patients. Results We identified recessive mutations of CHRNE in ten families, mutations in DOK7 in three families and mutations in COLQ, CHRNA1 and CHRNB1 in one family each. The mutation CHRNE c. 70insG was found in six families. We have repeatedly identified this mutation in patients from Spain and Portugal and haplotype studies indicate that CHRNE c. 70insG derives from a common ancestor. Conclusions Recessive mutations in CHRNE are the major cause of CMS in Southern Brazil with a common mutation introduced by Hispanic settlers. The second most common cause is mutations in DOK7. The minimum prevalence of CMS in Parana is 0.18/100 000

Risks Factors for Infections with Extended-Spectrum Beta-Lactamase-Producing Escherichia coli and Klebsiella pneumoniae at a Tertiary Care University Hospital in Switzerland

Abstract : Background: : There are considerable geographical differencesin the occurrence of extended-spectrum beta-lactamase(ESBL)-producing bacteria, both in the community and in thehospital setting. Our aim was to assess risk factors forbloodstream, urinary tract, and vascular catheter-associatedinfections with ESBL-producing Escherichia coli and Klebsiellapneumoniae at a tertiary care hospital in a low-prevalencecountry. Methods: : We performed a case-control study comparing 58patients with infections due to ESBL-producing E. coli orK. pneumoniae vs 116 controls with infections due to non-ESBL producing organisms at the University Hospital Zurich,Switzerland, between 1 July 2005 and 30 June 2007. Results: : Cases included 15 outpatients and 43 inpatients.Multivariable analyses found three risk factors for ESBL-producingisolates: begin of symptoms or recent antibioticpre-treatment in a foreign country (odds ratio [OR] 27.01,95% confidence interval [CI] 2.38-1,733.28], p = 0.042),antibiotic therapy within the year preceding the isolation ofthe ESBL-producing strain (OR 2.88, 95% CI 1.13-8.49,p = 0.025), and mechanical ventilation (OR 10.56, 95% CI1.06-579.10, p = 0.042). Conclusions: : The major risk factors for infections due toESBL-producing bacteria were travel in high-prevalencecountries, prior antibiotic use, and mechanical ventilationduring a stay in the intensive care unit. Community-acquiredinfections were documented in 17% of the patients.An early identification of risk factors is crucial to providingthe patients an optimal empiric antibiotic therapy and tokeep the use of carbapenems to a minimu

Spin relaxation of localized electrons in n-type semiconductors

The mechanisms that determine spin relaxation times of localized electrons in impurity bands of n-type semiconductors are considered theoretically and compared with available experimental data. The relaxation time of the non-equilibrium angular momentum is shown to be limited either by hyperfine interaction, or by spin-orbit interaction in course of exchange-induced spin diffusion. The energy relaxation time in the spin system is governed by phonon-assisted hops within pairs of donors with an optimal distance of about 4 Bohr radii. The spin correlation time of the donor-bound electron is determined either by exchange interaction with other localized electrons, or by spin-flip scattering of free conduction-band electrons. A possibility of optical cooling of the spin system of localized electrons is discussed.Comment: Submitted to the special issue "Optical Orientation", Semiconductor Science and Technolog

The Nernst effect and the boundaries of the Fermi liquid picture

Following the observation of an anomalous Nernst signal in cuprates, the Nernst effect was explored in a variety of metals and superconductors during the past few years. This paper reviews the results obtained during this exploration, focusing on the Nernst response of normal quasi-particles as opposed to the one generated by superconducting vortices or by short-lived Cooper pairs. Contrary to what has been often assumed, the so-called Sondheimer cancelation does not imply a negligible Nernst response in a Fermi liquid. In fact, the amplitude of the Nernst response measured in various metals in the low-temperature limit is scattered over six orders of magnitude. According to the data, this amplitude is roughly set by the ratio of electron mobility to Fermi energy in agreement with the implications of the semi-classical transport theory.Comment: Final version, Topical review for JPC

Advancements In Mechanical Sealing - API 682 Fourth Edition

TutorialAPI 682 is the leading document for mechanical seals in petrochemical, chemical, and pipeline services worldwide. It has combined the aspects of seal design, testing, standardization, and applications to provide the users and OEMs alike with a common source of information for mechanical seals. As seal technology has advanced, the standard has expanded to incorporate new seal designs, materials, seal selection guidance, and piping plans. Although the standard is not yet published, the final draft has been prepared and gives us notice of the upcoming requirements. This tutorial will cover the major changes introduced in the Fourth Edition

Mechanical Seals 101

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Advanced Mechanical Seals 201 - Demystifying Piping Plans and Support Systems

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