4,492 research outputs found

    Low temperature scattering with the R-matrix method: the Morse potential

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    Experiments are starting to probe collisions and chemical reactions between atoms and molecules at ultra-low temperatures. We have developed a new theoretical procedure for studying these collisions using the R-matrix method. Here this method is tested for the atom -- atom collisions described by a Morse potential. Analytic solutions for continuum states of the Morse potential are derived and compared with numerical results computed using an R-matrix method where the inner region wavefunctions are obtained using a standard nuclear motion algorithm. Results are given for eigenphases and scattering lengths. Excellent agreement is obtained in all cases. Progress in developing a general procedure for treating ultra-low energy reactive and non-reactive collisions is discussed.Comment: 18 pages, 6 figures, 3 tables, conferenc

    MRI in multiple myeloma : a pictorial review of diagnostic and post-treatment findings

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    Magnetic resonance imaging (MRI) is increasingly being used in the diagnostic work-up of patients with multiple myeloma. Since 2014, MRI findings are included in the new diagnostic criteria proposed by the International Myeloma Working Group. Patients with smouldering myeloma presenting with more than one unequivocal focal lesion in the bone marrow on MRI are considered having symptomatic myeloma requiring treatment, regardless of the presence of lytic bone lesions. However, bone marrow evaluation with MRI offers more than only morphological information regarding the detection of focal lesions in patients with MM. The overall performance of MRI is enhanced by applying dynamic contrast-enhanced MRI and diffusion weighted imaging sequences, providing additional functional information on bone marrow vascularization and cellularity. This pictorial review provides an overview of the most important imaging findings in patients with monoclonal gammopathy of undetermined significance, smouldering myeloma and multiple myeloma, by performing a 'total' MRI investigation with implications for the diagnosis, staging and response assessment. Main message aEuro cent Conventional MRI diagnoses multiple myeloma by assessing the infiltration pattern. aEuro cent Dynamic contrast-enhanced MRI diagnoses multiple myeloma by assessing vascularization and perfusion. aEuro cent Diffusion weighted imaging evaluates bone marrow composition and cellularity in multiple myeloma. aEuro cent Combined morphological and functional MRI provides optimal bone marrow assessment for staging. aEuro cent Combined morphological and functional MRI is of considerable value in treatment follow-up

    The Second Transmembrane Domain of P2X7 Contributes to Dilated Pore Formation

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    Activation of the purinergic receptor P2X7 leads to the cellular permeability of low molecular weight cations. To determine which domains of P2X7 are necessary for this permeability, we exchanged either the C-terminus or portions of the second transmembrane domain (TM2) with those in P2X1 or P2X4. Replacement of the C-terminus of P2X7 with either P2X1 or P2X4 prevented surface expression of the chimeric receptor. Similarly, chimeric P2X7 containing TM2 from P2X1 or P2X4 had reduced surface expression and no permeability to cationic dyes. Exchanging the N-terminal 10 residues or C-terminal 14 residues of the P2X7 TM2 with the corresponding region of P2X1 TM2 partially restored surface expression and limited pore permeability. To further probe TM2 structure, we replaced single residues in P2X7 TM2 with those in P2X1 or P2X4. We identified multiple substitutions that drastically changed pore permeability without altering surface expression. Three substitutions (Q332P, Y336T, and Y343L) individually reduced pore formation as indicated by decreased dye uptake and also reduced membrane blebbing in response to ATP exposure. Three others substitutions, V335T, S342G, and S342A each enhanced dye uptake, membrane blebbing and cell death. Our results demonstrate a critical role for the TM2 domain of P2X7 in receptor function, and provide a structural basis for differences between purinergic receptors. © 2013 Sun et al

    A novel xylan degrading β-D-xylosidase: purification and biochemical characterization

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    Aspergillus ochraceus, a thermotolerant fungus isolated in Brazil from decomposing materials, produced an extracellular b-xylosidase that was purified using DEAE-cellulose ion exchange chromatography, Sephadex G-100 and Biogel P-60 gel filtration. b-xylosidase is a glycoprotein (39 % carbohydrate content) and has a molecular mass of 137 kDa by SDS-PAGE, with optimal temperature and pH at 70 C and 3.0–5.5, respectively.b-xylosidase was stable in acidic pH (3.0–6.0) and 70 C for 1 h. The enzyme was activated by 5 mM MnCl2 (28 %)and MgCl2 (20 %) salts. The b-xylosidase produced by A. ochraceus preferentially hydrolyzed p-nitrophenyl-b- D-xylopyranoside, exhibiting apparent Km and Vmax values of 0.66 mM and 39 U (mg protein)-1 respectively, and to a lesser extent p-nitrophenyl-b-D-glucopyranoside. The enzyme was able to hydrolyze xylan from different sources,suggesting a novel b-D-xylosidase that degrades xylan. HPLC analysis revealed xylans of different compositions which allowed explaining the differences in specificity observed by b-xylosidase. TLC confirmed the capacity.This work was supported by the Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP), and the Conselho de Desenvolvimento Científico e Tecnológico (CNPq). J. A. J. and M. L. T. M. P are Research Fellows of CNPq. M. M. was a recipient of a FAPESP fellowship and this work is part of her Doctoral Thesis. It is also part of the project SISBIOTA CNPq: 563260/2010-6 and FAPESP: 2010/52322-3

    Quality of Life of Patients with Type 1 Diabetes Mellitus Using Insulin Analog Glargine Compared with NPH Insulin: A Systematic Review and Policy Implications

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    INTRODUCTION: Insulin analogue glargine (GLA) has been available as one of the therapeutic options for patients with type 1 diabetes mellitus to enhance glycemic control. Studies have shown that a decrease in the frequency of hypoglycemia episodes improves the Quality of Life (QoL) of diabetic patients. However, there are appreciable acquisition cost differences between different insulins. Consequently, a need to assess their impact on QoL to provide future guidance to health authorities. METHOD: A Systematic review (SR) of multiple databases including Medline, LILACS, Cochrane and EMBASE databases with several combinations of agreed terms involving randomized controlled trials (RCTs) and cohorts, as well as manual searches and gray literature was undertaken. The primary outcome measure was a change in QoL. The quality of the studies and the risk of bias was also assessed. RESULTS: Eight studies were eventually included in the systematic review out of 634 publications. Eight different QoL instruments were used (2 generic, 2 mixed and 4 specific), in which the Diabetes Treatment Satisfaction Questionnaire (DTSQs) was the most used. The systematic review did not consistently show any significant difference overall in QoL scores whether as part of subsets or combined into a single score with the use of GLA versus NPH insulin. Only in patients’ satisfaction measured by DTSQ was a better result consistently seen with GLA versus NPH insulin but not using the WED scale. However, none of the cohort studies scored a maximum on the Newcastle-Ottawa scale for quality and they generally were of moderate quality with bias in the studies. CONCLUSION: There was no consistent difference in QoL or patient reported outcomes when the findings from the eight studies were collated. In view of this, we believe the current price differential between GLA and NPH insulin in Brazil cannot be justified by these findings

    Predicting progression of mild cognitive impairment to dementia using neuropsychological data: a supervised learning approach using time windows

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    Background: Predicting progression from a stage of Mild Cognitive Impairment to dementia is a major pursuit in current research. It is broadly accepted that cognition declines with a continuum between MCI and dementia. As such, cohorts of MCI patients are usually heterogeneous, containing patients at different stages of the neurodegenerative process. This hampers the prognostic task. Nevertheless, when learning prognostic models, most studies use the entire cohort of MCI patients regardless of their disease stages. In this paper, we propose a Time Windows approach to predict conversion to dementia, learning with patients stratified using time windows, thus fine-tuning the prognosis regarding the time to conversion. Methods: In the proposed Time Windows approach, we grouped patients based on the clinical information of whether they converted (converter MCI) or remained MCI (stable MCI) within a specific time window. We tested time windows of 2, 3, 4 and 5 years. We developed a prognostic model for each time window using clinical and neuropsychological data and compared this approach with the commonly used in the literature, where all patients are used to learn the models, named as First Last approach. This enables to move from the traditional question "Will a MCI patient convert to dementia somewhere in the future" to the question "Will a MCI patient convert to dementia in a specific time window". Results: The proposed Time Windows approach outperformed the First Last approach. The results showed that we can predict conversion to dementia as early as 5 years before the event with an AUC of 0.88 in the cross-validation set and 0.76 in an independent validation set. Conclusions: Prognostic models using time windows have higher performance when predicting progression from MCI to dementia, when compared to the prognostic approach commonly used in the literature. Furthermore, the proposed Time Windows approach is more relevant from a clinical point of view, predicting conversion within a temporal interval rather than sometime in the future and allowing clinicians to timely adjust treatments and clinical appointments.FCT under the Neuroclinomics2 project [PTDC/EEI-SII/1937/2014, SFRH/BD/95846/2013]; INESC-ID plurianual [UID/CEC/50021/2013]; LASIGE Research Unit [UID/CEC/00408/2013

    Increasing boys' and girls' intention to avoid teenage pregnancy: a cluster randomised control feasibility trial of an interactive video drama based intervention in post-primary schools in Northern Ireland

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    Background: Adolescent men have a vital yet neglected role in reducing unintended teenage pregnancy (UTP). There is a need for gender-sensitive educational interventions. Objectives: To determine the value and feasibility of conducting an effectiveness trial of the If I Were Jack Relationship and Sexuality Education (RSE) intervention in a convenience quota sample of post-primary schools in Northern Ireland. Secondary objectives were to assess acceptability to schools, pupils (male/female, aged 14–15 years) and parents/guardians; to identify optimal delivery structures and systems; to establish participation rates and reach, including equality of engagement of different socioeconomic and religious types; to assess trial recruitment and retention rates; to assess variation in normal RSE practice; to refine survey instruments; to assess differences in outcomes for male and female pupils; to identify potential effect sizes that might be detected in an effectiveness trial and estimate appropriate sample size for that trial; and to identify costs of delivery and pilot methods for assessing cost-effectiveness. Design: Cluster randomised Phase II feasibility trial with an embedded process and economic evaluation. Intervention: A teacher-delivered classroom-based RSE resource – an interactive video drama (IVD) with classroom materials, teacher training and an information session for parents – to immerse young people in a hypothetical scenario of Jack, a teenager whose girlfriend is unintentionally pregnant. It addresses gender inequalities in RSE by focusing on young men and is designed to increase intentions to avoid UTP by encouraging young people to delay sexual intercourse and to use contraception consistently in sexual relationships. Main outcome measures: Abstinence from sexual intercourse (delaying initiation of sex or returning to abstinence) or avoidance of unprotected sexual intercourse (consistent correct use of contraception). Secondary outcomes included Knowledge, Attitudes, Skills and Intentions. Results: The intervention proved acceptable to schools, pupils and parents, as evidenced through positive process evaluation. One minor refinement to the parental component was required, namely the replacement of the teacher-led face-to-face information session for parents by online videos designed to deliver the intervention to parents/guardians into their home. School recruitment was successful (target 25%, achieved 38%). No school dropped out. Pupil retention was successful (target 85%, achieved 93%). The between-group difference in incidence of unprotected sex of 1.3% (95% confidence interval 0.55% to 2.2%) by 9 months demonstrated an effect size consistent with those reported to have had meaningful impact on UTP rates (resulting in an achievable sample size of 66 schools at Phase III). Survey instruments showed high acceptability and reliability of measures (Cronbach’s alpha: 0.5–0.7). Economic evaluation at Phase III is feasible because it was possible to (1) identify costs of delivering If I Were Jack (mean cost per pupil, including training of teachers, was calculated as £13.66); and (2) develop a framework for assessing cost-effectiveness. Conclusion: Trial methods were appropriate, and recruitment and retention of schools and pupils was satisfactory, successfully demonstrating all criteria for progression to a main trial. The perceived value of culture- and gender-sensitive public health interventions has been highlighted. Future work: Progression to a Phase III effectiveness trial. Trial registration: Current Controlled Trials ISRCTN99459996. Funding: This project was funded by the NIHR Public Health Research programme and will be published in full in Public Health Research; Vol. 5, No. 1. See the NIHR Journals Library website for further project information

    Anesthesia of Epinephelus marginatus with essential oil of Aloysia polystachya: an approach on blood parameters

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    This study investigated the anesthetic potential of the essential oil (EO) of Aloysia polystachya in juveniles of dusky grouper (Epinephelus marginatus). Fish were exposed to different concentrations of EO of A. polystachya to evaluate time of induction and recovery from anesthesia. In the second experiment, fish were divided into four groups: control, ethanol and 50 or 300 mu L L-1 EO of A. polystachya, and each group was submitted to induction for 3.5 min and recovery for 5 or 10 min. The blood gases and glucose levels showed alterations as a function of the recovery times, but Na+ and K+ levels did not show any alteration. In conclusion, the EO from leaves of A. polystachya is an effective anesthetic for dusky grouper, because anesthesia was reached within the recommended time at EO concentrations of 300 and 400 mu L L-1. However, most evaluated blood parameters showed compensatory responses due to EO exposure.Fundacao de Amparo a Pesquisa do Estado do Rio Grande do Sul/Programa de Apoio a Nucleos de Excelencia (FAPERGS/PRONEX) [10/0016-8]; Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq) [470964/2009-0]; Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior, Brazil (CAPES)info:eu-repo/semantics/publishedVersio

    Nanostructured 3D Constructs Based on Chitosan and Chondroitin Sulphate Multilayers for Cartilage Tissue Engineering

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    Nanostructured three-dimensional constructs combining layer-by-layer technology (LbL) and template leaching were processed and evaluated as possible support structures for cartilage tissue engineering. Multilayered constructs were formed by depositing the polyelectrolytes chitosan (CHT) and chondroitin sulphate (CS) on either bidimensional glass surfaces or 3D packet of paraffin spheres. 2D CHT/CS multi-layered constructs proved to support the attachment and proliferation of bovine chondrocytes (BCH). The technology was transposed to 3D level and CHT/CS multi-layered hierarchical scaffolds were retrieved after paraffin leaching. The obtained nanostructured 3D constructs had a high porosity and water uptake capacity of about 300%. Dynamical mechanical analysis (DMA) showed the viscoelastic nature of the scaffolds. Cellular tests were performed with the culture of BCH and multipotent bone marrow derived stromal cells (hMSCs) up to 21 days in chondrogenic differentiation media. Together with scanning electronic microscopy analysis, viability tests and DNA quantification, our results clearly showed that cells attached, proliferated and were metabolically active over the entire scaffold. Cartilaginous extracellular matrix (ECM) formation was further assessed and results showed that GAG secretion occurred indicating the maintenance of the chondrogenic phenotype and the chondrogenic differentiation of hMSCs
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