Utility of Social Support and Social Networks Theory in the PrEP Continuum of Care for Adolescents: A Review of the Literature

This literature review explores the potential of social support and social network theories in improving enrollment and retention in HIV pre-exposure prophylaxis (PrEP) care for at-risk adolescents aged 10-24. Seven peer-reviewed articles were analyzed to identify the critical role of social support and networks in providing informational, instrumental, emotional, and appraisal support. While biological family members are often the primary support figures, some studies acknowledge the importance of friend networks in promoting PrEP use. Families are generally willing to support their children\u27s use of PrEP, especially if they have prior knowledge of PrEP. Communication between parents and their children about HIV and PrEP is crucial in promoting PrEP awareness and use. Future studies should focus on developing and testing interventions that leverage the influence of families, partners, online support strategies, social identity support, and policy analysis to improve access to sexual health services for at-risk adolescents. In conclusion, social support and networks can potentially enhance the PrEP continuum of care among adolescents at risk for HIV. Future research should explore the effectiveness of interventions targeting these factors

Simple and multiple linear regressions between oil palm annual yields and yearly climatic variables over a 23-year-period (1990-2012) in the coastal zone of Cameroon

This study was aimed at determining whether variations in oil palm annual yields were significantly influenced by years of production, and at establishing if so simple and multiple linear regression relationships between oil palm annual yields and yearly climatic variables. Climatic and yield data were gathered in three locations (Bota-Limbe, Dizangué and Kienké) of the coastal zone of Cameroon, within the oil palm estates of three agro-industrial corporations. Yearly climatic variables were recorded for a period of 23 consecutive years (1990-2012); oil palm annual yields of five plots in each location were also recorded for the same period. Variations in annual yields (in metric-tons of bunches per hectare) were significantly influenced (P˂0.05) by years of production. Only a few yearly climatic variables however were significantly correlated with annual yields (none of the climatic variables in Bota-Limbe; evapotranspiration and rainfall height in Dizangué and insolation in Kienké). Low but significant, simple and multiple linear regressions were established that contributed to explain 18.10 to 54.60% of annual yields. Other mathematical relationships for more accurate predictions must be built, as for example curvilinear regressions; for linear regressions may not be sufficient to explain annual yields in their completeness.© 2015 International Formulae Group. All rights reserved.Keywords: Evapotranspiration, insolation, rainfall height, variations, predictions, mathematical relationship

Design and characterization of programmable DNA nanotubes

DNA self-assembly provides a programmable bottom-up approach for the synthesis of complex structures from nanoscale components. Although nanotubes are a fundamental form encountered in tile-based DNA self-assembly, the factors governing tube structure remain poorly understood. Here we report and characterize a new type of nanotube made from DNA double-crossover molecules (DAE-E tiles). Unmodified tubes range from 7 to 20 nm in diameter (4 to 10 tiles in circumference), grow as long as 50 μm with a persistence length of ~4 μm, and can be programmed to display a variety of patterns. A survey of modifications (1) confirms the importance of sticky-end stacking, (2) confirms the identity of the inside and outside faces of the tubes, and (3) identifies features of the tiles that profoundly affect the size and morphology of the tubes. Supported by these results, nanotube structure is explained by a simple model based on the geometry and energetics of B-form DNA

Essai d’optimisation de la production du palmier à huile (Elaeis guineensis J.) sur la base des données climatiques dans la région du sud-ouest Cameroun

L’étude vise à contribuer à l’estimation des productions du palmier à huile sur la base des données climatiques au Sud-Ouest du Cameroun.  L’hypothèse de départ est que les fluctuations interannuelles des rendements sont dues aux variations climatiques. Les paramètres climatiques avec leurs modalités et la production des régimes de palme ont été collectés dans la localité de Limbé, sur 5 ans. La mise en évidencedes fluctuations interannuelles des rendements du palmier à huile et des composantes climatiques a été établie grâce à une analyse de variance. Par contre, pour les composantes climatiques prises sur la même année, il n’existe pas de coefficients de corrélation significatifs entre le rendement moyen et les variables étudiées. De ce fait, aucune régression linéaire simple n’a pu être dégagée entre ces variables et le rendement annuel du palmier à huile. L’absence de données continues sur une longue période explique cette limite. Les modèles de prédiction des rendements théoriques du palmier à huile n’ont donc pas été générés. Il serait judicieux de mener davantage de prospections sur d’autres sites de palmier à huile. En outre, l’élaboration de modèles multivariés traduisant les effets des paramètres climatiques sur les rendements du palmier à huile peut être envisagée.Mots-clés : Elaeais guineensis, modélisation, climat, Cameroun

Evaluation of the single platform Muse® Auto CD4/CD4 % system in Cameroon

Background: according to who revised guidelines for scaling up antiretroviral therapy (ART) in adults and children living in resource-limited settings, there is an urgent need for laboratory monitoring, including the numeration of CD4 T cells.Objective: the study compared the muse® auto CD4/CD4% System for CD4 t cell enumeration in absolute counts and in percentages, to the Guava® AutoD4/CD4% System.Design: This was a prospective study using adults, adolescents, children and infant’s samples.Setting: The Centre International de Diagnostic Medical (CIDM), Yaounde, a research laboratory devoted to HIV screening and monitoring affiliated to the University of Yaounde I.Subjects: K3-EDTA-blood samples from 111 patients (77 adults, 12 adolescents, 18 children and 4 infants) were collected and tested. All participants signed an informed consent form whereas the guardian and parent of children signed the assent form.Results: the absolute CD4 t lymphocyte counts as well as the percentage CD4 lymphocyte of the Muse® AutoCD4/CD4% and GuavaAutoCD4/CD4% Systems, were highly correlated with an interclass correlation coefficient of 0.997 (95%CI: 0.996-0.998) and 0.991 (95% CI: 0.987-0.994) respectively. The Bland-Altman analysis limits of agreement were -5.79 cells/μl (95%CI: [-97.77; 86.19]) for the absolute CD4 T lymphocyte counts and -1.93 (95%CI: [-7.29; – 3.43]) for CD4 T lymphocyte percentage. The numbers of outliers were similar (6/111=5.41%) both for CD4 T lymphocyte counts and percentage. In addition, Cohen’s Kappa ranged from 0.95 to 1 according to CD4 T lymphocyte counts thresholds (p<0.001), showing agreement between both methods. Conclusion: this study demonstrates that the muse™ auto CD4/CD4% system constitutes a promising system for CD4 t cell counting comparable to existing reference methods, and should facilitate wider access to CD4 T cell enumeration for adults and children with HIV infection living in resource-limited countries

Understanding how the crowded interior of cells stabilizes DNA/DNA and DNA/RNA hybrids–in silico predictions and in vitro evidence

Amplification of DNA in vivo occurs in intracellular environments characterized by macromolecular crowding (MMC). In vitro Polymerase-chain-reaction (PCR), however, is non-crowded, requires thermal cycling for melting of DNA strands, primer-template hybridization and enzymatic primer-extension. The temperature-optima for primer-annealing and extension are strikingly disparate which predicts primers to dissociate from template during extension thereby compromising PCR efficiency. We hypothesized that MMC is not only important for the extension phase in vivo but also during PCR by stabilizing nucleotide hybrids. Novel atomistic Molecular Dynamics simulations elucidated that MMC stabilizes hydrogen-bonding between complementary nucleotides. Real-time PCR under MMC confirmed that melting-temperatures of complementary DNA–DNA and DNA–RNA hybrids increased by up to 8°C with high specificity and high duplex-preservation after extension (71% versus 37% non-crowded). MMC enhanced DNA hybrid-helicity, and drove specificity of duplex formation preferring matching versus mismatched sequences, including hair-pin-forming DNA- single-strands

Longitudinal associations between monetary value of the diet, DASH diet score and the allostatic load among middle-aged urban adults

Lower cost can lead to poorer-quality diets, potentially worsening metabolic profiles. We explored these pathways among urban adults. Longitudinal data were extracted from 1224-1479 participants in the Healthy Aging in Neighborhoods of Diversity across the Life Span (HANDLS) study. DASH(mean) (Dietary Approaches to Stop Hypertension) score was computed using four 24 h recalls (v1/v2: 2004-2013) linked with a national food price database to estimate monetary value of the diet [MVD(mean)]. Allostatic load (AL) was measured at visits 2 (v2) and 3 (v3) in 2009-2018. Mixed-effects regression and structural equation modeling (SEM) were conducted, linking MVD(mean)/DASH(mean) to AL [v2 and annual change(v3-v2)] and exploring mediating pathways between MVD(mean) and AL(v3) through DASH(mean), stratifying by sex, race and poverty status. MVD(mean) tertiles were linearly associated with contemporaneous DASH(mean), after energy adjustment. In mixed-effects regression models, DASH(mean) was consistently linked to lower AL(v2). DASH(mean) and MVD(mean) were positively associated with higher serum albumin(v2). In SEM, MVD(mean) was linked to AL(v3) through DASH(mean), mainly among Whites and specifically for the cholesterol and Waist-Hip-Ratio AL components. In summary, energy and other covariate-adjusted increase in MVD may have a sizeable impact on DASH which can reduce follow-up AL among urban White middle-aged adults. More studies are needed to replicate findings in comparable samples of urban adults

Supply, use and sustainability of ecosystem services in tropical forests: insights from the Dja region in southeastern Cameroon

Tropical forests provide numerous ecosystem services (ES) to human populations, but human-induced deforestation, degradation and defaunation are major threats to the structure, diversity and functioning of these ecosystems. In central Africa, tens of millions of people depend on the forest ecosystems for their daily livelihoods. In the specific context of extremely high poverty, the growing human population and their needs for forest products increase the threats on forest ecosystems. An integrated assessment of ES is needed in order to improve the sustainability of their use and to design adaptive management strategies. Here, we assessed the supply and use of ES by local populations in three contrasted forest management types in southeastern Cameroon: a protected area, a Forest Stewardship Council (FSC)-certified logging concession, and three community forests

Ricinodendron heudelotii (Euphorbiaceae) seed oil prevents DMBA-induced breast cancer under menopause-like conditions in Wistar rats

Despite efforts, breast cancer remains associated with a high incidence and mortality rate. Ricinodendron heudelotii also known as “Njansang,” is a plant used for cancer treatment. While several reports on the anticancer potential of its leaves exist, little is known about its seed oil. This study aimed to evaluate the in vitro and in vivo anti-breast cancer activity of “Njansang” seed oil. The inhibitory effect of “Njansang” seed oil was determined using MTT and CCK-8 dye reduction assays. Breast cancer was induced with DMBA and promoted with E2V (1 mg/kg) for 4 weeks in ovariectomized rats (menopausal condition). Evaluated parameters included tumor incidence, tumor mass and volume, histopathology, breast cancer biomarker CA 15–3, antioxidant status (CAT, GSH, MDA, NO, SOD), TNF-α and INFγ levels, lipid profile (total cholesterol, LDL-cholesterol, triglycerides and HDL-cholesterol), as well as toxicity parameters (ALT, AST, creatinine). “Njansang” oil significantly reduced the growth of ER+ (MCF-7) and triple negative (MDA-MB 231) adenocarcinoma cells in vitro as well as tumor incidence, tumor mass and CA 15–3 levels in vivo. It exhibited antioxidant activity, characterized by an increase in SOD and catalase activities, GSH levels and decreased MDA levels compared to the DMBA group. TNF-α and INF-γ levels were reduced following oil treatment, while total cholesterol, LDL-cholesterol and triglyceride levels were reduced. The aforementioned findings confirm the protective effects of “Njansang” oil on induced breast cancer in ovariectomized rats

Modeling ssDNA electrophoretic migration with band broadening in an entangled or cross-linked network

We use a coarse-grained model proposed by Graham and Larson based on the temporary network model by Schieber et al.. [1] to simulate the electrophoretic motion of ssDNA and corresponding band broadening due to dispersion. With dimensionless numbers reflecting the experimental physical properties, we are able to simulate ssDNA behavior under weak to moderate electric field strengths for chains with 8–50 entanglements per chain (∼1000–8500 14base pairs), and model smoothly the transition from reptation to oriented reptation. These results are fitted with an interpolation equation, which allows the user to calculate dimensionless mobilities easily from input parameters characterizing the gel matrix, DNA molecules, and field strengths. Dimensionless peak widths are predicted from mobility fluctuations using the central limit theorem and the assumption that the mobility fluctuations are Gaussian. Using results from previous studies of ssDNA physical properties (effective charge Ξq and Kuhn step length b K ) and sieving matrix properties (pore size or tube diameter a ), we give scaling factors to convert the dimensionless values to “real” experimental values, including the mobility, migration distance, and time. We find that the interpolation equation fits well the experimental data of ssDNA mobilities and peak widths, supporting the validity of the coarse-grained model. The model does not account for constraint release and hernia formation, and assumes that the sieving network is a homogeneous microstructure with no temperature gradients and no peak width due to injection. These assumptions can be relaxed in future work for more accurate prediction.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/56125/1/2783_ftp.pd