Multiple-Model Multiple Imputation for Longitudinal Count Data to Address Uncertainty in Missingness Mechanism

In this paper, an approach to generate imputed values for count variables to incorporate missing data mechanism uncertainty is proposed. For multiple imputation, a distribution is considered in such a manner that it can reflect missing data mechanism uncertainty. For combining the parameter estimation of these imputed data sets the rules of nested multiple imputation are used. The performance of the multiple imputations is investigated using some simulation studies. Also, a real data set is analyzed using the proposed approach

Enhancement of 2,3-butanediol production by Klebsiella pneumoniae PTCC 1290: Application of Taguchi methodology for process optimization

2,3-Butanediol production parameter optimization using Klebsiella pneumoniae PTCC 1290 was performed using the design of experiments available in the form of an orthogonal array and a software for automatic design and analysis of the experiments, both based on Taguchi protocol. Optimal levels of physical parameters and key media components namely temperature, pH, inoculum size, agitation, acetic acid and succinic acid were determined. 2,3-Butanediol production obtained from the 18 sets offermentation experiments performed with the selected factors and levels were further processed with Qualitek-4 software at bigger is better as quality character. The optimized conditions showed an enhanced 2,3-butanediol production of 35.8% (from 11.856 to 18.459 g l-1). The optimal combinations of factors obtained from the proposed design of experiments methodology was further validated by conducting fermentation experiments and the obtained results revealed an enhanced 2,3-butanediol production of 25.8%. Taguchi approach of design of experiments resulted in evaluating the main and interaction effects of the factors individually and in combinatio

Interplay of Fracture and Martensite Transformation in Microstructures:A Coupled Problem

We are witnessing a tremendous transition towards a society powered by net-zero carbon emission energy, with a corresponding escalating reliance on functional materials (FM). In recent years, the application of FM in multiphysics environments has brought new challenges to the mechanics and materials research communities. The underlying mechanism in FM, which governs several fundamental characteristics, is known as martensitic phase transformation (MPT). When it comes to the application of FM in the multiphysics context, a thorough understanding of the interplay between MPT and fracture plays a crucial role in FM design and application. In the present work, a coupled problem of crack nucleation and propagation and multivariant stress-induced MPT in elastic materials is presented using a finite element method based on Khachaturyan’s microelasticity theory. The problem is established based on a phase-field (PF) approach, which includes the Ginzburg–Landau equations with advanced thermodynamic potential and the variational formulation of Griffith’s theory. Therefore, the model consists of a coupled system of the Ginzburg–Landau equations and the static elasticity equation, and it characterizes evolution of distributions of austenite and two martensitic variants as well as crack growth in terms of corresponding order parameters. The numerical results show that crack growth does not begin until MPT has grown almost completely through the microstructure. Subsequent to the initial formation of the martensite variants, the initial crack propagates in such a way that its path mainly depends on the feature of martensite variant formations, the orientation and direction upon which the martensite plates are aligned, and the stress concentration between martensite plates. In addition, crack propagation behavior and martensite variant evaluations for different lattice orientation angles are presented and discussed in-detail

Community-based physical activity interventions among women: A systematic review

Objective: Review and assess the effectiveness of community-based physical activity interventions among women aged 18-65 years. Design: Systematic review Methods: To find relevant articles, the researcher selected reports published in English between 1 January 2000 and 31 March 2013. Systematic search was to find controlled-trial studies that were conducted to uncover the effect of community-based interventions to promote physical activity among women 18-65 years of age, in which physical activity was reported as one of the measured outcomes. The methodological quality assessment was performed using a critical appraisal sheet. Also, the levels of evidence were assessed for the types of interventions. Results: The literature search identified nine articles. Four of the studies were randomised and the others studies had high methodological quality. There was no evidence, on the basis of effectiveness, for social cognitive theory-based interventions and inconclusive evidence of effectiveness for the rest of interventions. Conclusions: There is insufficient evidence to assess the effectiveness of community-based interventions for enhancing physical activity among women. There is a need for high-quality randomised clinical trials with adequate statistical power to determine whether multicomponent and community-based intervention programmes increase physical activity among women, as well as to determine what type of interventions have a more effective and sustainable impact on women's physical activity. © 2015, BMJ. All rights reserved

Up-Regulation of Tmevpg1 and Rmrp LncRNA Levels in Splenocytes and Brain of Mouse with Experimental Autoimmune Encephalomyelitis

Background: Two long noncoding (lnc) RNAs, which have been recognized as Tmevpg1/Ifng-AS1/NeST and Rmrp play indispensable roles in the differentiation of TH1 and TH17, respectively. The aim of the present scientific study was to analyze the expression levels of the aforementioned lncRNAs in experimental autoimmune encephalomyelitis (EAE) as an animal model for multiple sclerosis (MS).Materials and Methods: Initially, EAE was induced in C57BL/6 mice via immunization by using MOG peptide. The leukocyte infiltration rate and demyelination of neuronal axons were determined. Secondly, the expression levels of Tmevpg1, Rmrp, Tbx21, and Rorc were analyzed in the cultured splenocytes and brain lysates, by using Real-Time PCR assay; eventually, the levels of interferon-gamma and interleukin-17 evaluated by ELISA.Results: Gene expression analysis revealed that Rorc expression in the splenocytes of EAE mice in comparison to the controls was elevated; however, Tbx21 expression did not show any significant difference. Tmevpg1 and Rmrp levels increased in the splenocytes of EAE mice (4.48 times and 39.70 times, respectively, p = 0.0001). Besides, in the brain lysate, the entire genes that have been mentioned were higher than the controls (Tmevpg1: 3.35 times p = 0.02 and Rmrp 11.21 times, p = 0.0001).Conclusion: The marked up-regulation in Tmevpg1 and Rmrp transcripts suggested the essential roles of lncRNAs in the pathogenesis of EAE and multiple sclerosis indeed. Further investigations are necessary to evaluate the values of these lncRNAs as the target for the therapy or molecular marker for disease monitoring

Protocol study: Sexual and reproductive health knowledge, information-seeking behaviour and attitudes among Saudi women: A questionnaire survey of university students

Copyright © 2014 Farih et al.; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.Background - Sexual and reproductive health (SRH), a basic right for women worldwide, is infrequently researched in countries in the Middle East and North Africa (MENA). No empirical studies of SRH among Saudi women exist. This protocol describes a study to explore the SRH knowledge, information-seeking behaviour and attitudes of Saudi female university students. Methods/Design - This study will administer a questionnaire survey to female students at 13 universities in Riyadh, Saudi Arabia. The questionnaire was developed following a literature search to identify relevant content, with psychometrically tested tools used when available. The content layout and the wording and order of the questions were designed to minimize the risk of bias. The questionnaire has been translated into Arabic and piloted in preparation for administration to the study sample. Ethical approval for the study has been granted (reference no. QMREC2012/54). After questionnaire administration, the data will be collated, analysed and reported anonymously. The findings will be published in compliance with reporting guidelines for survey research. Discussion - This study will be the first to provide fundamental information concerning Saudi females university students SRH knowledge and information needs.King Abdullah Scholarship Program, Saudi Arabi

A Broadband Ultrathin Nonlinear Switching Metamaterial

In this paper, an ultrathin planar nonlinear metamaterial slab is designed and simulated. Nonlinearity is provided through placing diodes in each metamaterial unit cell. The diodes are auto-biased and activated by an incident wave. The proposed structure represents a broadband switching property between two transmission and reflection states depending on the intensity of the incident wave. High permittivity values are presented creating a near zero effective impedance at low power states, around the second resonant mode of the structure unit cell; as the result, the incident wave is reflected. Increasing the incident power to the level which can activate the loaded diodes in the structure results in elimination of the resonance and consequently a drop in the permittivity values near the permeability one as well as a switch to the transmission state. A full wave as well as a nonlinear simulations are performed. An optimization method based on weed colonization is applied to the unit cell of the metamaterial slab to achieve the maximum switching bandwidth. The structure represents a 24% switching bandwidth of a 10 dB reduction in the reflection coefficient