390 research outputs found
Substrate-induced band gap opening in epitaxial graphene
Graphene has shown great application potentials as the host material for next
generation electronic devices. However, despite its intriguing properties, one
of the biggest hurdles for graphene to be useful as an electronic material is
its lacking of an energy gap in the electronic spectra. This, for example,
prevents the use of graphene in making transistors. Although several proposals
have been made to open a gap in graphene's electronic spectra, they all require
complex engineering of the graphene layer. Here we show that when graphene is
epitaxially grown on the SiC substrate, a gap of ~ 0.26 is produced. This gap
decreases as the sample thickness increases and eventually approaches zero when
the number of layers exceeds four. We propose that the origin of this gap is
the breaking of sublattice symmetry owing to the graphene-substrate
interaction. We believe our results highlight a promising direction for band
gap engineering of graphene.Comment: 10 pages, 4 figures; updated reference
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Towards person-centered neuroimaging markers for resilience and vulnerability in Bipolar Disorder
Improved clinical care for Bipolar Disorder (BD) relies on the identification of diagnostic markers that can reliably detect disease-related signals in clinically heterogeneous populations. At the very least, diagnostic markers should be able to differentiate patients with BD from healthy individuals and from individuals at familial risk for BD who either remain well or develop other psychopathology, most commonly Major Depressive Disorder (MDD). These issues are particularly pertinent to the development of translational applications of neuroimaging as they represent challenges for which clinical observation alone is insufficient. We therefore applied pattern classification to task-based functional magnetic resonance imaging (fMRI) data of the n-back working memory task, to test their predictive value in differentiating patients with BD (n=30) from healthy individuals (n=30) and from patients' relatives who were either diagnosed with MDD (n=30) or were free of any personal lifetime history of psychopathology (n=30). Diagnostic stability in these groups was confirmed with 4-year prospective follow-up. Task-based activation patterns from the fMRI data were analyzed with Gaussian Process Classifiers (GPC), a machine learning approach to detecting multivariate patterns in neuroimaging datasets. Consistent significant classification results were only obtained using data from the 3-back versus 0-back contrast. Using contrast, patients with BD were correctly classified compared to unrelated healthy individuals with an accuracy of 83.5%, sensitivity of 84.6% and specificity of 92.3%. Classification accuracy, sensitivity and specificity when comparing patients with BD to their relatives with MDD, were respectively 73.1%, 53.9% and 94.5%. Classification accuracy, sensitivity and specificity when comparing patients with BD to their healthy relatives were respectively 81.8%, 72.7% and 90.9%. We show that significant individual classification can be achieved using whole brain pattern analysis of task-based working memory fMRI data. The high accuracy and specificity achieved by all three classifiers suggest that multivariate pattern recognition analyses can aid clinicians in the clinical care of BD in situations of true clinical uncertainty regarding the diagnosis and prognosis
BSRS-5 (5-item Brief Symptom Rating Scale) scores affect every aspect of quality of life measured by WHOQOL-BREF in healthy workers
This study aims to evaluate and quantify the possible effect of psychological symptoms on healthy workers' quality of life (QOL). The workers were recruited from a factory in south Taiwan. We assessed their psychological symptoms with a 5-item brief symptom rating scale (BSRS-5) and measured the QOL using the Taiwanese version of the World Health Organization Quality of Life (WHOQOL)-BREF. Multiple linear regression analysis was conducted to explore the association between the two tools after control of confounding by other predictors. A total of 1,080 workers , who attended a physical examination, completed questionnaires and informed consent forms. Scores on the BSRS-5 significantly predicted scores in each domain and items of the WHOQOL-BREF. The magnitude of psychological domain score seemed to be affected the most; every 1 point increase in BSRS-5 was associated with a 0.39 raw score (equivalent to 2. 44 percentile) decrease in QOL. The sleep facet of WHOQOL appeared to have the highest association, followed by items of negative feelings, energy, and concentration. The BSRS-5 score is predictive for scores of all four domains and 26 items of the Taiwanese version of the WHOQOL-BREF for regular factory workers
Posttraumatic Stress Disorder, Depression, and HIV Risk Behavior Among Ohio Army National Guard Soldiers
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/96665/1/jts21777.pd
Dimensions of compulsive exercise across eating disorder diagnostic subtypes and the validation of the Spanish version of the compulsive exercise test
Objectives: Compulsive exercise in eating disorders has been traditionally considered as a behavior that serves the purpose of weight/shape control. More recently, it has been postulated that there may be other factors that drive the compulsive need to exercise. This has led to the development of the Compulsive Exercise Test (CET); a self-reported questionnaire that aims to explore the cognitive-behavioral underpinnings of compulsive exercise from a multi-faceted perspective. The objectives of this study were threefold: (1) to validate the Spanish version of the CET; (2) to compare eating disorder diagnostic subtypes and a healthy control group in terms of the factors that drive compulsive exercise as defined by the CET; (3) to explore how the dimensions evaluated in the CET are associated with eating disorder symptoms and general psychopathology.
Methods: The CET was administered to a total of 157 patients with an eating disorder [40 anorexia nervosa, 56 bulimia nervosa (BN), and 61 eating disorder not-otherwise-specified (EDNOS)] and 128 healthy weight/eating controls. Patients were assessed via a semi-structured interview to reach a DSM-IV-TR diagnosis. Additionally, all participants completed the Symptom Checklist-90-Revised (SCL-90R) and the Eating Disorders Inventory-2 (EDI-2).
Results: Confirmatory factor analysis demonstrated adequate goodness-of-fit to the original five-factor model of the CET. BN and EDNOS patients scored higher in the avoidance and rule-driven behavior, weight control, and total CET scales in comparison to the healthy controls, and higher across all scales apart from the exercise rigidity scale compared to the anorexia nervosa patients. Mean scores of the anorexia nervosa patients did not differ to those of the control participants, except for the mood improvement scale where the anorexia nervosa patients obtained a lower mean score. Mean scores between the BN and EDNOS patients were equivalent. The CET scales avoidance and rule-driven behavior, weight of control and total CET scores were positively correlated with the clinical assessment measures of the SCL-90R and EDI-2.
Conclusion: Compulsive exercise is a multidimensional construct and the factors driving compulsive exercise differ according to the eating disorder diagnostic subtype. This should be taken into account when addressing compulsive exercise during the treatment of eating disorders
Interleukin-1beta Promoter (−31T/C and −511C/T) Polymorphisms in Major Recurrent Depression
To elucidate a genetic predisposition to major depressive disorder, we investigated two polymorphisms (−31T/C and −511C/T) in the interleukin-1beta promoter region in patients who suffered from major recurrent depression. The aim of the current work was to compare alleles and genotype layout between patients with major recurrent depression and healthy people. We would like to indicate such combination of genotypes which corresponds with major recurrent depression. Correlations between genotypes for analyzed polymorphisms and number of episodes, number of points in Hamilton Depression Rating Scale, and age of onset were investigated as well. The study group consisted of 94 patients diagnosed with major recurrent depression. The control group included 206 healthy individuals. Both groups involved representatives of Caucasian population. Genotyping of polymorphisms was performed by using PCR-RFLP technique. A specific haplotype, composed of the C allele at −31 and the T allele at −511, has a tendency to have a statistically significant difference (p = 0.064) between patients and control group. Correspondence analysis revealed that genotype T/T at −31 and genotype C/C at −511 are associated with major recurrent depression. No association was found between genotypes for studied polymorphic sites and number of episodes, number of points in Hamilton Depression Rating Scale, and age of onset
Health Policy and Systems Research in Twelve Eastern Mediterranean Countries: a stocktaking of production and gaps (2000-2008)
<p>Abstract</p> <p>Background</p> <p>The objectives of this study are to: (1) profile the production of Health Policy and Systems Research (HPSR) published between 2000 and 2008 in 12 countries in the Eastern Mediterranean Region (EMR): Bahrain, Egypt, Jordan, Lebanon, Libya, Morocco, Oman, Palestine, Sudan, Syria, Tunisia, and Yemen; (2) identify gaps; and (3) assess the extent to which existing HPSR produced in the region addresses regional priorities pertaining to Health Financing, Human Resources for Health and the Role of the Non-State Sector. This is the first stocktaking paper of HPSR production and gaps in the EMR.</p> <p>Methods</p> <p>Articles indexed on Medline between years 2000 and 2008 for the 12 study countries were selected. A MeSH term based search was conducted using country names. Articles were assessed using a coding sheet adapted for the region which included themes on: Governance Arrangements, Financial Arrangements, Delivery Arrangements, and Implementation Strategies. Identified articles were matched against regional research priorities to assess the extent to which research production aligns with priorities.</p> <p>Results</p> <p>A total of 1,487 articles (11.94%) fit the criteria in the coding sheet. Results showed an increase in HPSR production which peaked after 2005. Most identified articles focused on Delivery Arrangements (68.1%), and Implementation Strategies (24.4%). Most HPSR addressed priorities in Human Resources for Health (39%<b>)</b>, and some articles focused on Health Financing (12%) and Role of the Non-State Sector (6.1%).</p> <p>Conclusions</p> <p>Despite global calls for producing and translating HPSR into policy, there are still significant gaps in the EMR. More efforts are needed to produce HPSR and align production and translation with the demand for evidence by policymakers. Findings can help inform and direct future plans and activities for the Evidence Informed Policy Network- EMR, World Health Organization- EMR, and the Middle East and North Africa Health Policy Forum, in addition to being useful for countries that host or are planning to host KT platforms in the region.</p
Automatic mapping of atoms across both simple and complex chemical reactions
Mapping atoms across chemical reactions is important for substructure searches, automatic extraction of reaction rules, identification of metabolic pathways, and more. Unfortunately, the existing mapping algorithms can deal adequately only with relatively simple reactions but not those in which expert chemists would benefit from computer's help. Here we report how a combination of algorithmics and expert chemical knowledge significantly improves the performance of atom mapping, allowing the machine to deal with even the most mechanistically complex chemical and biochemical transformations. The key feature of our approach is the use of few but judiciously chosen reaction templates that are used to generate plausible "intermediate" atom assignments which then guide a graph-theoretical algorithm towards the chemically correct isomorphic mappings. The algorithm performs significantly better than the available state-of-the-art reaction mappers, suggesting its uses in database curation, mechanism assignments, and - above all - machine extraction of reaction rules underlying modern synthesis-planning programs
Central Coherence in Eating Disorders: A Synthesis of Studies Using the Rey Osterrieth Complex Figure Test
Background: Large variability in tests and differences in scoring systems used to study central coherence in eating disorders may lead to different interpretations, inconsistent findings and between study discrepancies. This study aimed to address inconsistencies by collating data from several studies from the same research group that used the Rey Osterrieth Complex Figure Test (Rey Figure) in order to produce norms to provide benchmark data for future studies. Method: Data was collated from 984 participants in total. Anorexia Nervosa, Bulimia Nervosa, recovered Anorexia Nervosa, unaffected family members and healthy controls were compared using the Rey Figure. Results: Poor global processing was observed across all current eating disorder sub-groups and in unaffected relatives. There was no difference in performance between recovered AN and HC groups. Conclusions: This is the largest dataset reported in the literature and supports previous studies implicating poor global processing across eating disorders using the Rey Figure. It provides robust normative data useful for future studies
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