Two novel regulators of N-acetyl-galactosamine utilization pathway and distinct roles in bacterial infections

in MicrobiologyOpen (2015), 4(6), 983-1000

Bacterial pathogens can exploit metabolic pathways to facilitate their successful infection cycles, but little is known about roles of d-galactosamine (GalN)/ N-acetyl-d- galactosamine (GalNAc) catabolism ... [more ▼]

Bacterial pathogens can exploit metabolic pathways to facilitate their successful infection cycles, but little is known about roles of d-galactosamine (GalN)/ N-acetyl-d- galactosamine (GalNAc) catabolism pathway in bacterial pathogenesis. Here, we report the genomic reconstruction of GalN/GalNAc utilization pathway in Streptococci and the diversified aga regulons. We delineated two new paralogous AgaR regulators for the GalN/GalNAc catabolism pathway. The electrophoretic mobility shift assays experiment demonstrated that AgaR2 (AgaR1) binds the predicted palindromes, and the combined in vivo data from reverse transcription quantitative polymerase chain reaction and RNA-seq suggested that AgaR2 (not AgaR1) can effectively repress the transcription of the target genes. Removal of agaR2 (not agaR1) from Streptococcus suis 05ZYH33 augments significantly the abilities of both adherence to Hep-2 cells and anti-phagocytosis against RAW264.7 macrophage. As anticipated, the dysfunction in AgaR2-mediated regulation of S. suis impairs its pathogenicity in experimental models of both mice and piglets. Our finding discovered two novel regulators specific for GalN/GalNAc catabolism and assigned them distinct roles into bacterial infections. To the best of our knowledge, it might represent a first paradigm that links the GalN/GalNAc catabolism pathway to bacterial pathogenesis. [less ▲]

Two properties of vectors of quadratic forms in Gaussian random variables

in Teoriya Veroyatnostei i ee Primeneniya (2014), 59(2), 214-232

Two separable mechanisms are responsible for mental stress effects on high frequency heart rate variability: an intra-individual approach in a healthy and a diabetic sample

in International Journal of Psychophysiology (2015), 95(3), 299-303

Two Views on Text Structure: Using Rhetorical Structure Theory and Register & Genre Theory in Improving Students' Academic Writing

in Odense Working Papers in Language and Communication (2008), 29

Two worlds of educational research? Comparing the levels, objects, disciplines, methodologies and themes in educational research in the United Kingdom and Germany, 2005–2015

in Research in Comparative and International Education (2017), 12(4), 375-397

Embedded in social worlds, education systems and research reflect distinct national trajectories. We compare two contrasting traditions of educational research (ER). Whereas British ER exhibits a ... [more ▼]

Embedded in social worlds, education systems and research reflect distinct national trajectories. We compare two contrasting traditions of educational research (ER). Whereas British ER exhibits a multidisciplinary and pragmatic character, German ER reflects pedagogy and mainly humanities-based traditions. Yet, in both countries, policymakers’ growing demand for evidence in ER resulted in increased funding, specific research programs, and mandatory large-scale assessments. These have reshaped the field, suggesting more similar ER agendas. Based on a comprehensive original dataset of basic ER projects funded by the main grant- making agencies in both countries (2005–2015), we analyze five dimensions: levels, objects, disciplines, methodologies, and themes. We find epistemic drift, with partial convergence characterized by a multi-level focus, multidisciplinary approach, strongly empirical and quantitative methodology, and a premium on teaching and learning themes. The cases remain distinct in exploring systemic questions in a wider contextual frame (UK) or concentrating more narrowly on the individual learner (Germany). [less ▲]

Two years post-stroke, Luxembourgish informal caregivers’ life satisfaction and their couple and family repercussions

in Sociology of Health (2010)

This study aims to improve our understanding of the changes in the couple and family lives of stroke survivors’ caregivers and to analyse the relationships between the Caregivers’ Life Satisfaction (CLS ... [more ▼]

This study aims to improve our understanding of the changes in the couple and family lives of stroke survivors’ caregivers and to analyse the relationships between the Caregivers’ Life Satisfaction (CLS) and the social and emotional repercussions of the caregiving role, two years after this event. Life satisfaction, optimism about the future, happiness and other subjective well-being aspects have attracted the European policymakers, leading to the Eurofund to introduce a “life satisfaction” dimension in the European Quality of Life Surveys (EQLS). The general subjective appraisal of one’s life is now an indicator next to objective measures of economic performance, such as GDP. How is life satisfaction for the main informal caregivers of stroke-survivors, at the Grand-duchy of Luxembourg (one of the smallest UE country, 502 500 hab. (01/2010), 2600 km2). Individual and family upheavals stroke-related have a major effect on the survivor’s life, and on the close relatives and friends’ ones. «The self-assertion on the harmony of the stroke survivor-caregiver pairs» is the strategy to approach the issue. The implications of these changes are determined by the partners’ trajectory. The CLS is disrupted by stroke, but a lack of information remains on caregivers’ needs, mostly on the repercussions on the couple and family relationships and projects. Over twelve months, 62 pairs (among them 51 couples) of stroke survivors (64.4 mean age; majors impairments: sensory 53.2% and memory 38.7%) and their main informal caregivers (62 mean age, 61.7% women) consented to participate at a National Survey. Research assistants interviewed them at home, with a face-to-face questionnaire. Caregivers evaluated, on a four-point scale, a list of repercussions; these assertions were built up from a qualitative exploratory study. The LS ten-point scaled was dichotomised in “low (<=7 of 10)” and “high (>7 of 10) life satisfaction” (LLS vs HLS)”. Our research protocol was approved by the National Committee of Research Ethics and the Committee for Data Protection. Stroke survivors’ LS were lightly inferior than the CLS (mean=8) and no significant differences were observed between their socio-demographic characteristics. Comparing the responses obtained on the couple repercussions, the caregivers with LLS had emphasised the impacts of the care provided to their recipients: « The stroke was experienced as a drama that our couple has never overcome” (54.2 LLS vs 17,2% HLS; p≤0.001);“I cannot leave anymore the stroke survivor alone for a long time” (60.7% LLS vs 17.4% HLS; p=0.001); « The stroke has ended with all the life projects that as a couple we made» (45.8 LLS vs 11.1% HLS ; p≤ 0.05); “The stroke has brought serious turnovers in my couple” (57.1 LLS vs 25.9% HLS ; p≤ 0.05). Regarding family repercussions, the caregivers with LLS had underlined the impacts of their caregiving role: "The stroke is often a cause of the distance problems we have with our children" (23.1% LLS vs 0.0% HLS; p≤0.01), and “The stroke has brought serious turnovers in my family” (82.8% LLS vs 51.7% HLS; p≤0.05). CLS and survivors LS were close. Inequalities regarding CLS were identified. Evaluating repercussions on CLS is needed in enabling stroke survivors to live at home. Long-term informal care sustainability has been overlooked; innovative accompaniment and counselling are developed to follow Helsingborg Declaration on European Stroke Strategies. [less ▲]

Two years post-stroke: the effects of dissatisfaction with services and quality of information on patients’ quality of life in Luxembourg

in Best Investissements for Health (2013)

Stroke is the second cause of death and helps from socio-medical services and information are crucial for promoting post-stroke patient’s quality of life. We analysed the impact of dissatisfaction with ... [more ▼]

Stroke is the second cause of death and helps from socio-medical services and information are crucial for promoting post-stroke patient’s quality of life. We analysed the impact of dissatisfaction with these services and information on post-stroke patient’s quality of life taking into account socioeconomic factors and functional impairments, which remains little documented. Methods: All 2-year post-stroke patients admitted to all hospitals in Luxembourg were identified using the only care-expenditure-reimbursement national system database. Clinical diagnosis of cerebrovascular disease was confirmed. Ninety four patients living at home (mean age 65.5) were face-to-face interviewed to gather socioeconomic characteristics (sex, age, nationality, family structure, education, occupation, income and residence place) and to measure quality of life (using the Newcastle Stroke-Specific Quality of Life measure, noted Newsqol (assessing mobility, self-care, pain, cognition, vision, communication, feelings, relationships, emotion, sleep and fatigue) and dissatisfaction with various services and information. Data were analysed using multiple regression models. Results: Most functional impairments impacted multiple Newsqol dimensions. Language impairment related to most Newsqol dimensions (mobility, self-care, cognition, vision, communication, feelings, relationships, sleep and fatigue); memory impairment to pain, cognition, feeling, emotion, and sleep; motor impairment to mobility, self-care, pain, feeling and fatigue; visual impairment to relationships in addition to vision; sensory impairment to pain, communication, emotion and sleep. Controlling for all socioeconomic factors and functional impairments evidenced that dissatisfactions with helps and information about helps from community services were strongly associated with all Newsqol dimensions including mainly self-care, communication, mental feeling, relationships, emotion and sleep. Lack of information about stroke was associated with relationships and sleep. Conclusion: Improving help services and information about helps and cerebrovascular disease in chronic phase should highly impact patients’ quality of life. It is important to promote patient-centred care focusing on information need, financial need, and medical, technical and personal aids. [less ▲]

Two- and three-dimensional isogeometric cohesive elements for composite delamination analysis

in Composites. Part B, Engineering (2014), 60

We propose an automatic numerical method requiring minimal user intervention to simulate delamination in composite structures. We develop isogeometric cohesive elements for two- and three-dimensional ... [more ▼]

We propose an automatic numerical method requiring minimal user intervention to simulate delamination in composite structures. We develop isogeometric cohesive elements for two- and three-dimensional delamination by exploiting the knot insertion algorithm directly from CAD data to generate cohesive elements along delamination. A complete computational framework is presented including pre-processing, processing and post-processing. They are explained in detail and implemented in MIGFEM - an open source Matlab Isogemetric Analysis code developed by the authors. The composite laminates are modeled using both NURBS solid and rotation-free shell elements. Several two and three dimensional examples ranging from standard delamination tests (the mixed mode bending test) to the L-shaped specimen with a fillet, three dimensional (3D) double cantilever beam and a 3D singly curved thick-walled laminate are provided. The method proposed provides a bi-directional system in which one can go forward from CAD to analysis and backwards from analysis to CAD. This is believed to facilitate the design of composite structures. © 2013 Elsevier Ltd. All rights reserved. [less ▲]

A two-dimensional Isogeometric Boundary Element Method for elastostatic analysis

in Computer Methods in Applied Mechanics and Engineering (2012), 209-212

The concept of isogeometric analysis, where functions that are used to describe geometry in CAD software are used to approximate the unknown fields in numerical simulations, has received great attention ... [more ▼]

The concept of isogeometric analysis, where functions that are used to describe geometry in CAD software are used to approximate the unknown fields in numerical simulations, has received great attention in recent years. The method has the potential to have profound impact on engineering design, since the task of meshing, which in some cases can add significant overhead, has been circumvented. Much of the research effort has been focused on finite element implementations of the isogeometric concept, but at present, little has been seen on the application to the Boundary Element Method. The current paper proposes an Isogeometric Boundary Element Method (BEM), which we term IGABEM, applied to two-dimensional elastostatic problems using Non-Uniform Rational B-Splines (NURBS). We find it is a natural fit with the isogeometric concept since both the NURBS approximation and BEM deal with quantities entirely on the boundary. The method is verified against analytical solutions where it is seen that superior accuracies are achieved over a conventional quadratic isoparametric BEM implementation. © 2011 Elsevier B.V. [less ▲]

A Two-Dimensional Isogeometric Boundary Element Method For Linear Elastic Fracture

Scientific Conference (2014, January)