195 research outputs found

    Anisotropic tunneling in {InGaAsP}/{InP} multi-quantum barrier structure

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    We present magneto-photoluminescence experiments on a multi-quantum-barrier structure consisting of 31 period of wide (58 nm) quaternary wells of InGaAsP with the same lattice parameter as InP separated by thin (8 nm) InP barriers. The anomalous diamagnetic shift and the asymmetric broadening of the luminescence spectra evidence strong band filling in the tail of the density of states of the quaternary alloy, suggesting that tunneling transport through the InP barrier is anisotropic along the growth axis, due to different band lineups for the direct (InGaAsP-on-InP) and inverse (InP-on-InGaAsP) interfaces. This finding is supported by high resolution X-ray patterns, yielding evidence that the direct and inverse interfaces are smooth and display different chemical compositions

    Contamination of a high-cell-density continuous bioreactor

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    Continuous fermentations were carried out with a recombinant flocculent Saccharomyces cerevisiae strain in an airlift bioreactor. Once operating under steady state at a dilution rate of 0.45 h−1, the bioreactor was contaminated with Escherichia coli cells. The faster growing E. coli strain was washed out of the bioreactor and the recombinant, slower growing flocculating S. cerevisiae strain remained as the only species detected in the bioreactor. Flocculation, besides allowing for the realization of high-cell-density systems with corresponding unusual high productivity, may be used as a selective property for controlling some contamination problems associated with prolonged continuous operation.Fundação para a Ciência e Tecnologia -PRAXIS XXI/BD/11306/97

    Sulbactam pivoxil powder attributes and compatibility study with excipients

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    Background: Sulbactam pivoxil is an irreversible β-lactamase inhibitor that can be used with β-lactam antibiotics to improve antibacterial therapy by the oral route. Relevant properties of this drug for pharmaceutical manufacturing are not available in the open literature. In this work, a solid-state characterization of sulbactam pivoxil at the molecular, particle, and bulk levels was performed. Results: Particles exhibited a mean diameter of about 350 Οm, irregular shape crystals, and good flow properties. This work presents for the first time the crystal structure of this β-lactamase inhibitor obtained by X-ray diffraction analysis. Fourier-transform infrared results showed the characteristic bands of aliphatic hydrocarbons and ester groups. The differential scanning calorimetry curve exhibited a sharp endothermic peak at 109 °C corresponding to sulbactam pivoxil melting. The thermogravimetric curve revealed a mass loss at 184 °C associated with a decomposition process. This powder showed a moisture content of 0.34% and a water activity of 0.463. Potential interactions between sulbactam pivoxil and common pharmaceutical excipients were evaluated by thermal analysis. The endothermic peak and the enthalpies of melting were preserved in almost all the analyzed mixtures. Conclusion: The powder was constituted by micro-sized crystals of sulbactam pivoxil that had suitable physicochemical properties for processing in controlled humidity environments. Thermal analyses suggested that sulbactam pivoxil is compatible with most of the evaluated excipients. The information obtained in the present study is relevant for the development, manufacturing, and storage of formulations that include sulbactam pivoxil.Fil: Gallo, Loreana Carolina. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia; Argentina. Consejo Nacional de Investigaciones Científicas y TÊcnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; ArgentinaFil: Gonzålez Vidal, Noelia Lujån. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia; Argentina. Consejo Nacional de Investigaciones Científicas y TÊcnicas. Centro Científico Tecnológico Conicet - Bahía Blanca; ArgentinaFil: Ferreira, Fabio F.. Universidad Federal do Abc; BrasilFil: Ramírez Rigo, María Veronica. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia; Argentina. Consejo Nacional de Investigaciones Científicas y TÊcnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; Argentin

    Performance of alere determine HIV-1/2 Ag/Ab combo rapid test for acute HIV infection: A case report | Performance del test rapido Alere Determine HIV-1/2 Ag/Ab Combo nell?infezione acuta da HIV: Un caso clinic

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    We describe a case of symptomatic acute HIV infection in a young man where a fourth-generation rapid screening test combining HIV-specific antibody and p24 antigen was negative. In highly suspicious cases of acute HIV infection, plasma HIV RNA assays together with conventional, non-rapid screening tests should be used

    Role of PII proteins in nitrogen fixation control of Herbaspirillum seropedicae strain SmR1

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    <p>Abstract</p> <p>Background</p> <p>The PII protein family comprises homotrimeric proteins which act as transducers of the cellular nitrogen and carbon status in prokaryotes and plants. In <it>Herbaspirillum seropedicae</it>, two PII-like proteins (GlnB and GlnK), encoded by the genes <it>glnB </it>and <it>glnK</it>, were identified. The <it>glnB </it>gene is monocistronic and its expression is constitutive, while <it>glnK </it>is located in the <it>nlmAglnKamtB </it>operon and is expressed under nitrogen-limiting conditions.</p> <p>Results</p> <p>In order to determine the involvement of the <it>H. seropedicae glnB </it>and <it>glnK </it>gene products in nitrogen fixation, a series of mutant strains were constructed and characterized. The <it>glnK<sup>- </sup></it>mutants were deficient in nitrogen fixation and they were complemented by plasmids expressing the GlnK protein or an N-truncated form of NifA. The nitrogenase post-translational control by ammonium was studied and the results showed that the <it>glnK </it>mutant is partially defective in nitrogenase inactivation upon addition of ammonium while the <it>glnB </it>mutant has a wild-type phenotype.</p> <p>Conclusions</p> <p>Our results indicate that GlnK is mainly responsible for NifA activity regulation and ammonium-dependent post-translational regulation of nitrogenase in <it>H. seropedicae</it>.</p

    Terminology - glossary including acronyms and quotations in use for the conservative spinal deformities treatment: 8th SOSORT consensus paper

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    <p>Abstract</p> <p>Background</p> <p>This report is the SOSORT Consensus Paper on Terminology for use in the treatment of conservative spinal deformities. Figures are provided and relevant literature is cited where appropriate.</p> <p>Methods</p> <p>The Delphi method was used to reach a preliminary consensus before the meeting, where the terms that still needed further clarification were discussed.</p> <p>Results</p> <p>A final agreement was found for all the terms, which now constitute the base of this glossary. New terms will be added after being discussed and accepted.</p> <p>Discussion</p> <p>When only one set of terms is used for communication in a place or among a group of people, then everyone can clearly and efficiently communicate. This principle applies for any professional group. Until now, no common set of terms was available in the field of the conservative treatment of scoliosis and spinal deformities. This glossary gives a common base language to draw from to discuss data, findings and treatment.</p

    Guidelines on "Standards of management of idiopathic scoliosis with corrective braces in everyday clinics and in clinical research": SOSORT Consensus 2008

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    <p>Abstract</p> <p>Background</p> <p>Reported failure rates,(defined based on percentage of cases progressing to surgery) of corrective bracing for idiopathic scoliosis are highly variable. This may be due to the quality of the brace itself, but also of the patient care during treatment. The latter is sometimes neglected, even though it is considered a main determinant of good results among conservative experts of SOSORT. The aim of this paper was to develop and verify the Consensus on management of scoliosis patients treated with braces</p> <p>Methods</p> <p>We followed a Delphi process in four steps, distributing and gradually changing according to the results a set of recommendations: we involved the SOSORT Board twice, then all SOSORT members twice, with a Pre-Meeting Questionnaire (PMQ), and during a Consensus Session at the SOSORT Athens Meeting with a Meeting Questionnaire (MQ). We set a 90% agreement as the minimum to be reached.</p> <p>Results</p> <p>We had a 71% response rate to PMQ, and 66.7% to MQ. Since the PMQ we had a good agreement (no answers below 72% – 70.2% over 90%). With the MQ the agreement consistently increased for all the answers previously below 90% (no answers below 83%, 75% over 90%). With increasing experience in bracing all numerical criteria tended to become more strict. We finally produced a set of 14 recommendations, grouped in 6 Domains (Experience/competence, Behaviours, Prescription, Construction, Brace Check, Follow-up).</p> <p>Conclusion</p> <p>The Consensus permits establishment of recommendations concerning the standards of management of idiopathic scoliosis with bracing, with the aim to increase efficacy and compliance to treatment. The SOSORT recommends to professionals engaged in patient care to follow the guidelines of this Consensus in their clinical practice. The SOSORT criteria should also be followed in clinical research studies to achieve a minimum quality of care. If the aim is to verify the efficacy of bracing these criteria should be companions of the methodological research criteria for bracing proposed by other societies.</p

    Relationship between vertebral fractures, bone mineral density, and osteometabolic profile in HIV and Hepatitis B and C-infected patients treated with ART

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    Objective: The purpose of our study was to evaluate the alterations of bone metabolism and the prevalence of vertebral fractures in the population with HIV and hepatitis B and C seropositivity in treatment with antiretroviral drugs (HAART). Methods: We selected 83 patients with diagnosis of HIV, HBV, HCV infection. In all these patients biochemical examinations of phospho-calcium metabolism and a densitometry of lumbar spine were performed. We also evaluated lateral spine X-rays in order to analyze the presence of vertebral deformities and to define their severity. As a control group we analyzed the prevalence of vertebral fractures in a group of 40 non-infectious patients. Results: We selected 82 seropositive patients, 46 males and 37 females, with a median age of 55 \ub1 10 years. Out of these patients, 55 were infected by HIV, 12 were infected by HBV, 11 presented HIV and HCV co-infection and 4 were HCV+. The prevalence of hypovitaminosis D in the studied population was 53%, while the prevalence of osteoporosis and osteopenia was 14 and 48%, respectively. The average T-score in the fractured population was -1.9 SD. The viral load and the CD4+ cell count were respectively, directly, and inversely correlated with the number and severity of vertebral fractures. Antiretroviral therapy regimen containing TDF and PI was a significant determinant of the presence of vertebral deformities. The use of these drugs was also associated with lower levels of vitamin D and higher bone turnover levels compared to other antiretroviral drugs. Conclusions: HIV patients suffer from bone fragility, particularly at spine, independently by the level of bone mineral density. In this population, the T-score threshold for the risk of fracture is higher than that usually used in general population. For this reason, it would be indicated to perform an X-ray of the spine in order to detect vertebral deformities even in patients with a normal or slighlty reduced bone mineral density

    Specific exercises performed in the period of brace weaning can avoid loss of correction in Adolescent Idiopathic Scoliosis (AIS) patients: Winner of SOSORT's 2008 Award for Best Clinical Paper

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    <p>Abstract</p> <p>Background</p> <p>Exercises are frequently performed in order to improve the efficacy of bracing and avoid its collateral effects. Very frequently there is a loss of correction during brace weaning in AIS treatment.</p> <p>Aim</p> <p>To verify the efficacy of exercises in reducing correction loss during brace weaning.</p> <p>Study Design</p> <p>Retrospective controlled study.</p> <p>Population</p> <p>Sixty-eight consecutive patients (eight males), age 15 ¹ 1 and Cobb angle 22 ¹ 8° at start of brace weaning.</p> <p>Methods</p> <p>The start of brace weaning was defined as the first visit in which the wearing of brace for less than 18/24 hours was prescribed (according to our protocol, at Risser 3). Patients were divided into two groups according to whether or not exercises were performed: (1) EX (exercises), included 39 patients and was further divided into two sub-groups: SEAS (who performed exercises according to our institute's protocol, 14 patients) and OTH (other exercises, 25 patients) and (2) CON (controls, 29 patients) that was divided into two other sub-groups: DIS (discontinuous exercises, 19 patients) and NO (no exercises, 10 patients). Complete brace weaning was defined as the first visit in which the brace was no longer prescribed (ringapophysis closure or Risser 5, according to our protocol).</p> <p>ANOVA and Chi Square tests were performed.</p> <p>Results</p> <p>There was no difference between groups at baseline. However, at the end of treatment, 2.7 years after the start of the weaning process, Cobb angle increased significantly in both the DIS and NO groups (3.9° and 3.1° Cobb, respectively). The SEAS and OTH groups did not change. Comparing single groups, OTH (with respect to DIS) had a significant difference (P < 0.05).</p> <p>Conclusion</p> <p>Exercises can help reduce the correction loss in brace weaning for AIS.</p

    Advance EFFIS report on Forest Fires in Europe, Middle East and North Africa 2017

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    This report contains the annual summary of the fire season of 2017 with an analysis of fire danger and areas mapped in the European Forest Fire Information System (EFFIS).JRC.E.1-Disaster Risk Managemen
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