In pursuit of blending polymers with carbon nanotubes

A liquid-solid phase separation method has been developed here to separate polymer/CNT blended phases with specific bundle size distribution from master heterogeneous polymer/CNT dispersions. This liquid-solid phase separation is triggered through addition of a non-solvent in the system. The fundamental issue of dispersing carbon nanotubes (CNTs) dispersion within a polymer matrix is also addressed in this work by studying a non-solvent induced liquid-solid phase separation process in polyacrylonitrile/CNT composite systems. To visualize the effect of phase separation, hybrid polymer/CNT buckypapers were formed through filtration. The hybrid film morphology is graded showing a distinct CNT-rich and polymer-rich layer. Examination of this layered structure reveals the separation of CNTs with specific bundle size. CNTs were uniformly dispersed within the polymer-rich layer due to a preferred polymer-CNT interaction during phase separation. Experimental, theoretical, and molecular dynamics studies were performed to show the fundamental mechanism behind layer formation in the composites and to understand the specificity of preferential polymer-CNT interactions. To this end, a geometric dependence described by a ‘cylinder-in-sphere’ model was established and shows a link between the critical CNT bundle size and polymer radius of gyration (Rg), which is dictates preferential polymer-CNT interactions. This model represents the geometric relationship required to form a blended polymer-CNT phase in the system under the phase separation conditions used. Understanding the use of phase separation as well as this geometrical dependence between filler and polymer is important to pinpoint nano-filler dispersion limits. Identifying these limits is critical toward the processing of superior polymer-based composites which fully utilizes the nano-filler reinforcement. Please click Additional Files below to see the full abstract

A STUDY OF UNDERGRADUATE STUDENTS' ATTITUDE, MOTIVATION AND DIFFICULTIES ON THE USE OF MOBILE VOCABULARY LEARNING, ASSUMPTION UNIVERSITY

This study investigates the undergraduates’ attitudes, motivation, and learning difficulties in using mobile devices via vocabulary learning. The participants of this research are full-time undergraduates studying at Suvarnabhumi Campus, Assumption University (AU). This study used a mixed-method and focused on the exploratory design. For the questionnaire survey, 200 participants were selected using convenience sampling from the population. For the semi-structured interview, 15 participants were selected by using simple random sampling. The findings indicated that although 100% of the participants have mobile devices, some still used a traditional method, and the most popular vocabulary applications are Duolingo and BaiCiZhan. Also, students’ attitudes toward using mobile devices were HIGH as the overall mean score (M) = 3.68. The indication is that students have positive attitudes towards using mobile devices at Assumption University. Moreover, students’ motivation towards using mobile devices in AU is also HIGH. The overall mean score (M) = 3.68. As suggested, AU students are highly motivated to use mobile devices in teaching and learning. Lastly, students’ difficulties with using mobile devices are MODERATE, with the overall mean score (M) = 2.76. This can be interpreted those students were having moderate difficulties with using mobile devices. Based on the findings, a few pedagogical implications were discussed, and recommendations for students and teachers were suggested to foster mobile vocabulary learning in the English language classroom

Strategies for Developing an Institutional Repository: A Case Study of ScholarWorks@ UMass Amherst

ScholarWorks@UMass Amherst is an institutional repository that collects, manages, and disseminates intellectual output of UMass Amherst faculty, researchers, and students. In less than five years, it has become one of the top five Digital Commons repositories with more than 23,000 items and over half-a-million full-text downloads. ScholarWorks content recruitment strategies are examined as a case study for the development of an institutional repository. The authors aim to provide best practices for developing a digital repository in academic settings and inspire colleagues to explore and adapt new strategies

CURVE SPRINTING KINEMATICS EXHIBITED BY ATHLETES USING A SINGLE, TRANS-TIBIAL PROSTHESIS

The purpose of our study was to determine whether kinematics exhibited during the curve section of a 200 m sprint are influenced by ‘limb type’ (prosthetic vs nonprosthetic limb) or ‘prosthetic limb side’ (‘inside’ compared to the ‘outside’ of the curve). Two video cameras (60 Hz) were used to capture 13 male athletes using a single, trans-tibial prosthesis during an international, 200 m T-44 competition. From mixed-model ANOVA (p < .05), prosthetic and nonprosthetic limb kinematics were different, but differences were dependent on the prosthetic limb side. The inside versus outside prosthetic limb may be affected more due to the rotational influences that affect the inside and outside foot differently. Therefore, athletes whose prosthetic limb was on the inside may be at a disadvantage compared to those with an outside prosthetic limb

Familial [corrected] transmission of coronary heart disease: a cohort study of 80,214 Swedish adoptees linked to their biological and adoptive parents.

BACKGROUND: Studies of adoptees have the potential to disentangle the contributions of genetic versus family environmental factors in the familiar transmission of coronary heart disease (CHD) because adoptees do not share the same family environment as their biological parents. The aims of this study were as follows: (1) to examine the risk of CHD in adopted men and women with at least one biological parent with CHD and (2) to examine the risk of CHD in adopted men and women with at least one adoptive parent with CHD. METHODS: The Swedish Multigenerational register was used to follow all Swedish-born adoptees (born in or after 1932, n = 80,214) between January 1, 1973, and December 31, 2008, for CHD. The risk of CHD was estimated in adopted men and women with at least one biological parent with CHD and adopted men and women with at least one adoptive parent with CHD. The control groups consisted of adopted men or women without a biological parent with CHD or adopted men or women without an adoptive parent with CHD. RESULTS: Adopted men and women with at least one biological parent with CHD (n = 749) were 1.4 to 1.6 times (statistically significant, 95% CI) more likely to have CHD than adoptees without a biological parent with CHD. In contrast, men and women with at least one adoptive parent with CHD (n = 1,009) were not at increased risk of the disease. CONCLUSIONS: These findings (based on validated hospital diagnoses unbiased by recall) suggest that the familiar transmission of CHD from parents to offspring is more related to genetic factors than to family environmental factors

Analysis of oligonucleotide array experiments with repeated measures using mixed models

BACKGROUND: Two or more factor mixed factorial experiments are becoming increasingly common in microarray data analysis. In this case study, the two factors are presence (Patients with Alzheimer's disease) or absence (Control) of the disease, and brain regions including olfactory bulb (OB) or cerebellum (CER). In the design considered in this manuscript, OB and CER are repeated measurements from the same subject and, hence, are correlated. It is critical to identify sources of variability in the analysis of oligonucleotide array experiments with repeated measures and correlations among data points have to be considered. In addition, multiple testing problems are more complicated in experiments with multi-level treatments or treatment combinations. RESULTS: In this study we adopted a linear mixed model to analyze oligonucleotide array experiments with repeated measures. We first construct a generalized F test to select differentially expressed genes. The Benjamini and Hochberg (BH) procedure of controlling false discovery rate (FDR) at 5% was applied to the P values of the generalized F test. For those genes with significant generalized F test, we then categorize them based on whether the interaction terms were significant or not at the α-level (α(new )= 0.0033) determined by the FDR procedure. Since simple effects may be examined for the genes with significant interaction effect, we adopt the protected Fisher's least significant difference test (LSD) procedure at the level of α(new )to control the family-wise error rate (FWER) for each gene examined. CONCLUSIONS: A linear mixed model is appropriate for analysis of oligonucleotide array experiments with repeated measures. We constructed a generalized F test to select differentially expressed genes, and then applied a specific sequence of tests to identify factorial effects. This sequence of tests applied was designed to control for gene based FWER

Identification of gene expression patterns using planned linear contrasts

BACKGROUND: In gene networks, the timing of significant changes in the expression level of each gene may be the most critical information in time course expression profiles. With the same timing of the initial change, genes which share similar patterns of expression for any number of sampling intervals from the beginning should be considered co-expressed at certain level(s) in the gene networks. In addition, multiple testing problems are complicated in experiments with multi-level treatments when thousands of genes are involved. RESULTS: To address these issues, we first performed an ANOVA F test to identify significantly regulated genes. The Benjamini and Hochberg (BH) procedure of controlling false discovery rate (FDR) at 5% was applied to the P values of the F test. We then categorized the genes with a significant F test into 4 classes based on the timing of their initial responses by sequentially testing a complete set of orthogonal contrasts, the reverse Helmert series. For genes within each class, specific sequences of contrasts were performed to characterize their general \u27fluctuation\u27 shapes of expression along the subsequent sampling time points. To be consistent with the BH procedure, each contrast was examined using a stepwise Studentized Maximum Modulus test to control the gene based maximum family-wise error rate (MFWER) at the level of alphanew determined by the BH procedure. We demonstrated our method on the analysis of microarray data from murine olfactory sensory epithelia at five different time points after target ablation. CONCLUSION: In this manuscript, we used planned linear contrasts to analyze time-course microarray experiments. This analysis allowed us to characterize gene expression patterns based on the temporal order in the data, the timing of a gene\u27s initial response, and the general shapes of gene expression patterns along the subsequent sampling time points. Our method is particularly suitable for analysis of microarray experiments in which it is often difficult to take sufficiently frequent measurements and/or the sampling intervals are non-uniform

Identification of gene expression patterns using planned linear contrasts

BACKGROUND: In gene networks, the timing of significant changes in the expression level of each gene may be the most critical information in time course expression profiles. With the same timing of the initial change, genes which share similar patterns of expression for any number of sampling intervals from the beginning should be considered co-expressed at certain level(s) in the gene networks. In addition, multiple testing problems are complicated in experiments with multi-level treatments when thousands of genes are involved. RESULTS: To address these issues, we first performed an ANOVA F test to identify significantly regulated genes. The Benjamini and Hochberg (BH) procedure of controlling false discovery rate (FDR) at 5% was applied to the P values of the F test. We then categorized the genes with a significant F test into 4 classes based on the timing of their initial responses by sequentially testing a complete set of orthogonal contrasts, the reverse Helmert series. For genes within each class, specific sequences of contrasts were performed to characterize their general \u27fluctuation\u27 shapes of expression along the subsequent sampling time points. To be consistent with the BH procedure, each contrast was examined using a stepwise Studentized Maximum Modulus test to control the gene based maximum family-wise error rate (MFWER) at the level of alphanew determined by the BH procedure. We demonstrated our method on the analysis of microarray data from murine olfactory sensory epithelia at five different time points after target ablation. CONCLUSION: In this manuscript, we used planned linear contrasts to analyze time-course microarray experiments. This analysis allowed us to characterize gene expression patterns based on the temporal order in the data, the timing of a gene\u27s initial response, and the general shapes of gene expression patterns along the subsequent sampling time points. Our method is particularly suitable for analysis of microarray experiments in which it is often difficult to take sufficiently frequent measurements and/or the sampling intervals are non-uniform

Familial and neighborhood effects on psychiatric disorders in childhood and adolescence

Background: More knowledge is needed on potential associations between individual-, family-, and neighborhood-level factors and psychiatric disorders in children and adolescents. Aims: To examine associations between, individual-, family-, and neighborhood-level factors and incident internalizing (anxiety and mood) disorders and externalizing (ADHD and conduct) disorders in children and adolescents, and to estimate the relative contributions of family and neighborhood to individual variation in these disorders. Method: We performed a three-level logistic regression on all 542,195 children born in Sweden in 1992-1996, nested in 427,954 families, which in turn were nested in 8475 neighborhoods. The children were followed from 2000 to 2010 for incident internalizing and externalizing psychiatric disorders, assessed from medical records. Results: 26,514 children (4.8%) were diagnosed with internalizing or externalizing psychiatric disorders. Approximately 29% of the total individual variance in internalizing disorders could be attributed to the family level, which includes both genetic and family environmental effects, and 5% to the neighborhood level. The corresponding figures for externalizing disorders were 43.5% and 5.5%, respectively. After adjustment for individual-level sociodemographic factors, high neighborhood deprivationwas associated with increased risks of externalizing and internalizing psychiatric disorders (odds ratio [OR] = 1.37, 95% credible interval [CI] = 1.25-1.50 and OR = 1.34, 95% CI = 1.25-1.45, respectively), including conduct disorder (OR = 2.01, 95% CI = 1.58-2.55), anxiety disorders (OR = 1.40, 95% CI = 1.29-1.52), and mood disorders (OR = 1.21, 95% CI, 1.09-1.35). The strongest association between neighborhood deprivation and ADHD was observed in moderately deprived neighborhoods (OR = 1.31, 95% CI = 1.19-1.44). Conclusions: These findings call for policies to promote mental health that consider potential influences from children's family and neighborhood environments. Trial registration: Not applicable

Justice, poverty, and electricity decarbonization

Drawing from examples in Germany, California, and Australia, we show that large scale integration of renewable energy in existing electricity grids does not necessarily lead to cheaper electricity, the strengthening of energy security, or the enhancement of economic equity. Indeed, efforts to integrate renewable energy into the grid can thwart efforts to reduce chronic poverty. Planners around the world need to be cautious, pragmatic and realistic when attempting to similarly decarbonize their energy systems