Rôle du 4-hydroxynonénal dans la régulation du métabolisme des chondrocytes arthrosiques

Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal

Validation d'une mesure d'observation des habiletés sociales au préscolaire

Le but de cette recherche est de concevoir et de valider une mesure d'observation permettant d'évaluer les habiletés sociales au préscolaire. Toutes les habiletés évaluées sont reconnues comme étant nécessaires à l'établissement de relations harmonieuses entre pairs et comme étant un important facteur de protection au préscolaire pour les enfants agressifs. Au préscolaire, l'agressivité et le rejet social sont les principaux risques associés à un déficit des habiletés sociales. La procédure utilisée dans cette étude est une tâche de coopération contrôlée et une grille permettant la codification de cinq habiletés sociales. Cette grille est donc composée de 5 échelles mesurant: la capacité de coopérer, de partager, d'offrir son aide, de proposer des idées et de prendre contact. Afin de valider cette grille, 30 enfants agressifs et 30 enfants non agressifs ont été comparés sur les dimensions suivantes: la présence d'habiletés sociales et la qualité de l'émission de celles-ci, le rejet par les pairs et la formation de liens d'amitié réciproques. Les résultats indiquent que les enfants non-agressifs présentent plus de comportements favorisant la prise de contact et ils offrent davantage leur aide que les enfants agressifs. Également, un déficit des habiletés sociales coopérer, offrir mon aide et prendre contact est associé au rejet par les pairs. De plus, les résultats démontrent que l'habileté proposer des idées est fortement corrélée avec la formation de liens d'amitiés réciproques. Cette grille présente des coefficients intra-classe qui varient selon les échelles de 0,83 à 0,94, ce qui indique des taux d'accord inter-juges qui varient de très bons à excellents. Finalement, les résultats permettent d'affirmer que cette mesure d'observation des habiletés sociales est valide et fiable. ______________________________________________________________________________ MOTS-CLÉS DE L’AUTEUR : Observation, Mesure, Habiletés sociales, Préscolaire, Agressivité

Quantifying relative fish abundance with eDNA : a promising tool for fisheries management

1. Assessment and monitoring of exploited fish populations are challenged by costs, logistics and negative impacts on target populations. These factors therefore limit large-scale effective management strategies. 2. Evidence is growing that the quantity of eDNA may be related not only to species presence/absence, but also to species abundance. In this study, the concentrations of environmental DNA (eDNA) from a highly prized sport fish species, Lake Trout Salvelinus namaycush (Walbaum 1792), were estimated in water samples from 12 natural lakes and compared to abundance and biomass data obtained from standardized gillnet catches as performed routinely for fisheries management purposes. To reduce environmental variability among lakes, all lakes were sampled in spring, between ice melt and water stratification. 3. The eDNA concentration did not vary significantly with water temperature, dissolved oxygen, pH and turbidity, but was significantly positively correlated with relative fish abundance estimated as catch per unit effort (CPUE), whereas the relationship with biomass per unit effort (BPUE) was less pronounced. 4. The value of eDNA to inform about local aquatic species distribution was further supported by the similarity between the spatial heterogeneity of eDNA distribution and spatial variation in CPUE measured by the gillnet method. 5. Synthesis and applications. Large-scale empirical evidence of the relationship between the eDNA concentration and species abundance allows for the assessment of the potential to integrate eDNA within fisheries management plans. As such, the eDNA quantitative method represents a promising population abundance assessment tool that could significantly reduce the costs associated with sampling and increase the power of detection, the spatial coverage and the frequency of sampling, without any negative impacts on fish populations

Large electronic bandwidth in solution-processable pyrene crystals: The role of close-packed crystal structure

We examine the interdependence of structural and electronic properties of two substituted pyrene crystals by means of combined spectroscopic probes and density-functional theory calculations. One derivative features n-hexyl side groups, while the other one contains branched silanyl groups. Both derivatives form triclinic crystal structures when grown from solution, but the electronic dispersion behavior is significantly different due to differences in $\pi$-$\pi$ overlap along the $a$ crystal axis. Both systems display dispersion of 0.40-0.45 eV in the valence band, suggesting a high intrinsic hole mobility. However, the dispersion is primarily along the a-axis in the silanyl-substituted derivative, but less aligned with this crystal axis in the hexyl-substituted material. This is a direct consequence of the diferences in co-facial $\pi$ electron overlap revealed by the crystallographic studies. We find that photophysical defects, ascribed to excimer-like states, point to the importance of localized trap states. Substituted pyrenes are useful model systems to unravel the interplay of crystal structure and electronic properties in organic semiconductors.Comment: 25 pages, 8 figure

From VIH-TAVIE™ to TAVIE-WOMAN™: Development of a Web-Based Virtual Nursing Intervention to Meet the Specific Needs of Women Living With HIV

The web-based virtual nursing intervention VIH-TAVIE™ was designed to help people living with HIV (PLWH) adhere to their antiretroviral treatment (ART). The content of the intervention is generic and gender neutral. However, it is recognised that women living with HIV (WLWH) experience their condition in a unique way and face gender-specific challenges regarding ART intake. Consequently, it seemed appropriate to adapt VIH-TAVIE™ specifically for women. The purpose of this paper is to present the qualitative results of an evaluative study of VIH-TAVIE™ that describe the experience of six WLWH who received the web-based computer-delivered intervention and to present the content and specificities of an offshoot intervention under development, TAVIE-Woman™. The following themes emerged from the content analysis of interviews with the WLWH about : 1) presence of actual nurse on site to facilitate transition to virtual mode; 2) virtual nurse humanises experience of computer-delivered intervention; 3) learners’ appreciation of medium and content; and 4) perceived benefits following participation in the intervention. To adapt VIH-TAVIETM for women, discussions were also held with a healthcare team in a mother-child university hospital centre. The gender-specific content added to TAVIE-WomanTM included digital storytelling of HIV-positive women, various topics about changing ARV medication during pregnancy, neonatal ART prophylaxis, disclosure  to children,  adapting to life with HIV, selecting a birth-control method, and social support. Ultimately, the purpose of TAVIE-WomanTM is to support WLWH by offering them 24/7 access to tailored education and reliable quality information

Alterations of metabolic activity in human osteoarthritic osteoblasts by lipid peroxidation end product 4-hydroxynonenal

4-Hydroxynonenal (HNE), a lipid peroxidation end product, is produced abundantly in osteoarthritic (OA) articular tissues, but its role in bone metabolism is ill-defined. In this study, we tested the hypothesis that alterations in OA osteoblast metabolism are attributed, in part, to increased levels of HNE. Our data showed that HNE/protein adduct levels were higher in OA osteoblasts compared to normal and when OA osteoblasts were treated with H(2)O(2). Investigating osteoblast markers, we found that HNE increased osteocalcin and type I collagen synthesis but inhibited alkaline phosphatase activity. We next examined the effects of HNE on the signaling pathways controlling cyclooxygenase-2 (COX-2) and interleukin-6 (IL-6) expression in view of their putative role in OA pathophysiology. HNE dose-dependently decreased basal and tumour necrosis factor-α (TNF-α)-induced IL-6 expression while inducing COX-2 expression and prostaglandin E(2 )(PGE(2)) release. In a similar pattern, HNE induces changes in osteoblast markers as well as PGE(2 )and IL-6 release in normal osteoblasts. Upon examination of signaling pathways involved in PGE(2 )and IL-6 production, we found that HNE-induced PGE(2 )release was abrogated by SB202190, a p38 mitogen-activated protein kinase (MAPK) inhibitor. Overexpression of p38 MAPK enhanced HNE-induced PGE(2 )release. In this connection, HNE markedly increased the phosphorylation of p38 MAPK, JNK2, and transcription factors (CREB-1, ATF-2) with a concomitant increase in the DNA-binding activity of CRE/ATF. Transfection experiments with a human COX-2 promoter construct revealed that the CRE element (-58/-53 bp) was essential for HNE-induced COX-2 promoter activity. However, HNE inhibited the phosphorylation of IκBα and subsequently the DNA-binding activity of nuclear factor-κB. Overexpression of IKKα increased TNF-α-induced IL-6 production. This induction was inhibited when TNF-α was combined with HNE. These findings suggest that HNE may exert multiple effects on human OA osteoblasts by selective activation of signal transduction pathways and alteration of osteoblastic phenotype expression and pro-inflammatory mediator production

Efficacy of adaptive e-learning for health professionals and students : a systematic review and meta-analysis

Objective Although adaptive e-learning environments (AEEs) can provide personalised instruction to health professional and students, their efficacy remains unclear. Therefore, this review aimed to identify, appraise and synthesise the evidence regarding the efficacy of AEEs in improving knowledge, skills and clinical behaviour in health professionals and students. Design Systematic review and meta-analysis. Data sources CINAHL, EMBASE, ERIC, PsycINFO, PubMed and Web of Science from the first year of records to February 2019. Eligibility criteria Controlled studies that evaluated the effect of an AEE on knowledge, skills or clinical behaviour in health professionals or students. Screening, data extraction and synthesis Two authors screened studies, extracted data, assessed risk of bias and coded quality of evidence independently. AEEs were reviewed with regard to their topic, theoretical framework and adaptivity process. Studies were included in the meta-analysis if they had a non-adaptive e-learning environment control group and had no missing data. Effect sizes (ES) were pooled using a random effects model. Results From a pool of 10 569 articles, we included 21 eligible studies enrolling 3684 health professionals and students. Clinical topics were mostly related to diagnostic testing, theoretical frameworks were varied and the adaptivity process was characterised by five subdomains: method, goals, timing, factors and types. The pooled ES was 0.70 for knowledge (95% CI −0.08 to 1.49; p.08) and 1.19 for skills (95% CI 0.59 to 1.79; p<0.00001). Risk of bias was generally high. Heterogeneity was large in all analyses. Conclusions AEEs appear particularly effective in improving skills in health professionals and students. The adaptivity process within AEEs may be more beneficial for learning skills rather than factual knowledge, which generates less cognitive load. Future research should report more clearly on the design and adaptivity process of AEEs, and target higher-level outcomes, such as clinical behaviour

Institutional effects on nurses’ working conditions: a multi-group comparison of public and private non-profit and for-profit healthcare employers in Switzerland

Background: In response to the need for competitive recruitment of nurses resulting from the worldwide nursing shortage, employers need to attract and retain nurses by promoting their competitive strengths in their working conditions (WCS) and by addressing their competitive weaknesses. This study investigated workplace differences between public hospitals (PuHs), private for-profit hospitals (PrHs), socio- medical institutions (SOMEDs), home care services (HCs), private medical offices (PrOs) and non-profit organisations (NPOs), helping to provide a foundation for competition-oriented institutional employer branding and to increase transparency in the labour market for nurses. Methods: Data from the Swiss Nurses at Work study of the career paths of 11 232 nurses who worked in Switzerland between 1970 and 2014 were subjected to secondary analysis, assessing the effect of institutional characteristics on self-reported determinants of job satisfaction (such as WCS) using multivariate linear regression and post hoc tests with Bonferroni-adjusted significance levels. Principal component analysis was used to reduce the number of WCS in the original study. Results: Nurses at PuHs and PrHs were less likely to experience autonomy, flexibility of work hours and participation in decision-making than those at other workplaces. Although PuHs were rated higher than PrHs in terms of satisfaction with salary and advancement opportunities, they were associated with more alienating work factors, such as stress and aggression. SOMED workplaces were significantly more often associated with alienating conditions and low job satisfaction, but were rated higher than the other institutions in terms of participation in decision-making. The nurses’ ratings implied that PrO workplaces were more likely to offer a mild work environment, social support and recognition than other institutions, but that advancement opportunities were limited. NPO workplaces were associated with the highest degree of autonomy, flexibility, participation, recognition, organisational commitment and job satisfaction. In these respects, HC and NPO workplaces received similar ratings, although the HC workplaces were associated with a significantly lower organisational commitment and significantly lower job satisfaction. Conclusions: Due to their structural characteristics, NPOs, SOMEDs and HCs can attract nurses seeking greater self-determination, PuHs can attract career-oriented nurses, and PrOs and PrHs are likely to attract nurses through offering less-stressful working conditions