Prevalence of Hepatitis B among Students from the University of Lomé, Togo in 2015

Objective: Hepatitis B virus (HBV) is endemic in sub-Saharan Africa where more than 80 million subjects are chronic carriers. However, screening is not systematic in the population and prevalence data are scarce, especially among the youth population. The objective of this study was to estimate the prevalence of HBV and its correlates among first-year University students at the University of Lomé. Study design: A cross-sectional survey was conducted between November 2015 and January 2016 at the University of Lomé during the annual checkup offered to newly enrolled students. Method: A self-administered questionnaire was used to collect data on demographics and sexual behaviors, and rapid tests were used for the detection of Antigen HBS (HBsAg) and HIV in each participant. A logistic regression model was performed to identify factors associated with HBsAg positivity. Results: A total of 800 students (56.2% were men) were screened among 1505 students who participated in the study. The median age was 20 years (IQR: [18 - 21]). The overall prevalence of HBsAg was 4.6% (95% CI: [3.2 - 6.3]): 5.8% among men and 3.1% among women (p = 0.04). The prevalence of HIV was 0.8;95%CI [0.3% - 1.6%] and one case (0.1%) of coinfection HIV and HBV was identified. Factors associated with HBsAg positivity were male gender [adjusted Odds Ratio (aOR) = 2.08, 95% CI: 1.02 - 5.00, p = 0.0447] and ever having a sexual relationship [aOR = 2.44;95% CI = 1.11 - 5.78, p= 0.0264]. Conclusion: This study among university students demonstrates that the prevalence of HBV is high among this population and that there is a need for prevention programs to target this vulnerable population. This is an additional argument toward HBV screening and treatment among students during annual health check.

中温固体氧化物燃料电池阴极材料LaBiMn_2O_6的制备与性能

采用固相法合成了中温固体氧化物燃料电池（IT-SOFCs）阴极材料La Bi Mn2O6,并利用X射线衍射（XRD）和电化学阻抗谱（EIS）进行表征。结果表明该材料与电解质Ce0.7Bi0.3O1.85（CBO）在1 000℃烧结12 h不发生反应。交流阻抗和直流极化测试结果发现,阴极极化电阻随测试温度的增加而逐渐减小,700℃空气中的极化电阻为0.71Ω·cm2;氧分压测试结果显示,在600～700℃范围内,电极反应的速率控制步骤为电极上发生的电荷转移反应。电极过电位为85 m V时,700℃的阴极电流密度达到216 m A·cm-2,表明La Bi Mn2O6是一种潜在的中温固体氧化物燃料电池（IT-SOFCs）阴极材料。

Chasing the queens of the alien predator of honeybees: A water drop in the invasiveness ocean

The Yellow-legged hornet, Vespa velutina , was accidentally introduced in France in 2004, and then spread rapidly through the French territory but also to adjacent European countries (Spain, Portugal, and Belgium). During summer and autumn, V. velutina workers hunt domestic honeybees, Apis mellifera, for feeding their larvae. The impact of this alien species is mainly economic, beekeepers experiencing heavy colony losses, but also ecological, V. velutina hunting other pollinators. In their year-round life cycle, nest initiation by single queen during spring is the critical stage. In invaded areas, spring queen trapping using food baits has been promoted by apicultural unions in order to limit V. velutina population expansion. The goals of this work were 1) to evaluate the yield of this method, 2) to identify appropriate sites for trapping, 3) to identify potential optimal climatic windows of capture, and 4) to quantify the impact on local entomofauna. Our results showed that water proximity enhances trapping but not beehives proximity, and that trapping is inefficient if average week temperatures are below 10°C. Although the trapping effect on biodiversity should be studied more carefully, spring queen trapping is highly questionable unless specific attractants could be proposed.

Effect of Macronutrients, Cytokinins and Auxins, on <i>in Vitro</i>Organogenesis of <i>Thymus vulgaris</i>L.

The present study reports an efficient protocol for in vitro propagation of Thymus vulgaris L., an aromatic and medicinal plant in Morocco. Initially, we performed in vitro multiplication of Thymus vulgaris explants existing in the laboratory and obtained from micropropagation by shoot tip culture. Afterwards, we have evaluated the effect of six macronutrients. After that, seven cytokinins (Kin, BAP, 2iP, DPU, Adenine, Zeatine and TDZ) in three different concentrations (0.46, 0.93, 2.32 μM) have been evaluated to optimize cultures multiplication and elongation. Moreover, the effect of three auxins (IAA, IBA and NAA) at 0.57 μM, combined to 4 cytokinins (Kin, BAP, DPU and Ad.) at 0.46 μM, on shoot rooting has been studied. Thereby, MS medium has been proved the most favorable for plantlets growing. Also, we found that the addition of certain cytokinins, specifically 0.46 Kin, 0.46 and 0.93 BAP, 0.46 2iP, 0.46 DPU, 0.46 Ad. and 0.46 Zeat., ensures better multiplication and growth of vitroplants. In addition, multiplication and rooting of cultures were well optimized after addition 0.46 Kin + 0.57 IAA or NAA, 0.46 DPU + 0.57 IBA and 0.46 Ad. + 0.57 IBA combinations to the culture medium. Lastly, plantlets with roots were successfully acclimatized to ex-vitro conditions and these latter served as a source to establish in vitro culture again.

Microdialysis in awake macaque monkeys for central nervous system pharmacokinetics

Background: The brain bioavailability of novel small molecules developed to address central nervous system disease is classically documented through ex vivo or in vivo analyses conducted in rodent models. Data acquired in rodent models are, however,not easily transferrable to human as the pharmacokinetic and pharmacodynamics profiles of the species are quite different.Methods: Using drugs selected for their differential transport across the blood-brain barrier, we here demonstrate the feasibility of brain microdialysis in normal vigil macaque monkey by measuring brain extracellular fluid bioavailability of carbamazepine, digoxin, oxycodone, and quinidine.Results: All drugs, but digoxin, were found in dialysate samples. Drugs that are substrate of P-glycoprotein show a difference of bioavailability or brain pharmacokinetic parameters between rodents and primates.Conclusion: Data suggest that brain microdialysis in vigil macaque monkey, the species of choice for classic pharmacokinetic/pharmacodynamics studies could help predicting human brain bioavailability of a small molecule depending on the protein involved in the efflux transport from the brain.

Micropropagation and Acclimatization of Common Oregano (Origanum vulgare L. Subsp. vulgare) by Shoot Tip Culture

Origanum vulgare L. is a commercially valued species with remarkable biological properties. It is subject to over-exploitation practices that seriously threaten its sustainability for future generations. Thus, micropropagation serves as a tool for the protection and domestication of this species. In this study, we established an in vitro vegetative propagation protocol for Origanum vulgare. This is done through the axillary bud technique by carrying out various tests. Six culture media (MS, MSm, N30K, SD, SH and B5) were tested. Therefore, SD was chosen for the following experiments. Seven cytokinins (adenine (Ad), N6-(2-isopentenyl) (2ip), zeatin (Zeat), kinetin (Kin), benzyladenine (BAP), 1,3-diphenylurea (DPU) and thidiazuron (TDZ) at 5 concentrations (0.44, 1.33, 2.22, 3.11 and 4.44 μM/L) were evaluated. Thus, Kin at 3.11 μM allowed high regeneration of vitroplants, optimal elongation, total rooting of explants, maximum bud multiplication, and absence of hyperhydric explants. In fact, the integration of auxins (indole-3-acetic acid (IAA), indole-3-butyric acid (IBA), and 1-naphthaleneacetic acid (NAA)) into the culture medium and their combinations with 3.11 μM Kinetin contributed to the optimization of the root part. Thus, it was improved in particular in the case of 3.11 μM Kin and 6.27 μM IBA. Three polyamines (Putrescine, Spermidine and Spermine) at different concentrations (1.134, 3.402, 5.67, 7.938 and 11.34 μM/L) combined at 3.11 μM Kin and 6.27 μM IBA were tested. In fact, 1.304 μM putrescine was considered to be the most suitable for in vitro culture of explants, since it allowed optimal propagation of buds and roots, also a high rate of regeneration and rhizogenesis. GA3 at 1.15 μM combined with 3.11 μM Kin and 6.27 μM IBA permitted maximum bud multiplication. The acclimatization was carried out successfully using vitroplants showing good foliar and root development. Thus, three months after acclimatization, the seedlings were transferred into large pots under natural light and temperature conditions. Almost all acclimatized plants developed flowers in the first year between May and July.

Spectroscopic studies and Rietveld refinement of strontium-britholites

Strontium-britholites whose chemical formula was Sr10-xLax（PO4）6-x（SiO4）xF2, where x=0, 1, 2, and 4 were prepared by solid state reaction. The structural refinement carried out using the Rietveld method indicated that La^3＋ ions were located into the two sites with a strong preference for metal （2） sites especially for low contents. A progressive shift of the F position along the c-axis outside the centre of the triangle formed by metal （2）-atoms was observed with the increase of x. The infrared and Raman spectra exhibited the characteristic vibration modes of PO4 and SiO4groups confirming the incorporation of this last group into the apatite structure. The 295i MAS-NMR spectra exhibited one resonance peak confirming the data obtained by X-ray diffraction, indicating that P and Si were located in the same crystallographic site.

Morphological and mechanical analysis of natural marble joints submitted to shear tests

In order to evaluate the influence of the surface morphology on the mechanical behavior of twelve natural marble joints, very accurate topography measurements of joint surfaces under constant normal load （CNL） conditions were performed before and after shear tests. The surface topography was carried out using a three-dimensional （3D） laser-scanning profilometer with a parallel grid at a regular interval of 500 gin. Each surface before shearing was reconstructed by geostatistical methods according to eight different directions. A quantitative description of surfaces was performed using global and directional statistical parameters. These parameters allow to determine the surface anisotropy and to divide the .joints into three groups of similar morphology according to a given direction. Each sample of the same group is submitted to the same normal stress but to different shear rates ranging from 5 to 20 gm/s. The influences of normal stress and shear rate on the mechanical behavior of the discontinuities were investigated, as well as the influence of the sample morphology on its dilatancy behavior. The morphology data of upper and lower walls also permit to quantify the contact areas before testing. After the shear tests, sheared surfaces were scanned again and reconstructed according to the shearing direction. Based on the topography data of joint surfaces obtained before and after shearing, damage zones that occurred during shearing were located for both walls of each .joint. These characterizations of joint surfaces contribute to a better understanding of the shearing behavior of natural discontinuities.

Morphology of the ^(13)CO(3–2) millimetre emission across the gas disc surrounding the triple protostar GG Tau A using ALMA observations

Observations by the Atacama Large Millimetre/sub-millimetre Array of the dust continuum and ^13 CO（3–2） millimetre emissions of the triple stellar system GG Tau A are analysed,giving evidence for a rotating gas disc and a concentric and coplanar dust ring. The present work complements an earlier analysis（Tang et al.） by exploring detailed properties of the gas disc. A 95% confidence level upper limit of 0.24＂（34 au） is placed on the disc scale height at a distance of 1＂（140 au） from the central stars. Evidence for Keplerian rotation of the gas disc is presented,with the rotation velocity reaching-3.1 km s^-1 at 1＂ from the central stars,and a 99% confidence level upper limit of 9% is placed on relative contribution from a possible in-fall velocity. Variations of the intensity across the disc area are studied in detail and confirm the presence of a hot spot in the south-eastern quadrant. However several other significant intensity variations,in particular a depression in the northern direction,are also revealed. Variations of the intensity are found to be positively correlated to variations of the line width. Possible contributions to the measured line width are reviewed,suggesting an increase of the disc temperature and opacity with decreasing distance from the stars.

The Algebraic Immersed Interface and Boundary Method for Elliptic Equations with Jump Conditions

A new simple fictitious domain method, the algebraic immersed interface and boundary (AIIB) method, is presented for elliptic equations with immersed interface conditions. This method allows jump conditions on immersed interfaces to be discretized with a good accuracy on a compact stencil. Auxiliary unknowns are created at existing grid locations to increase the degrees of freedom of the initial problem. These auxiliary unknowns allow imposing various constraints to the system on interfaces of complex shapes. For instance, the method is able to deal with immersed interfaces for elliptic equations with jump conditions on the solution or discontinuous coefficients with a second order of spatial accuracy. As the AIIB method acts on an algebraic level and only changes the problem matrix, no particular attention to the initial discretization is required. The method can be easily implemented in any structured grid code and can deal with immersed boundary problems too. Several validation problems are presented to demonstrate the interest and accuracy of the method.

Dynamic Fracture of a Semi-Crystalline Bio-Based Polymer Pipe: Effect of Temperature

The influence of temperature on the resistance to rapid crack propagation of a semi-crystalline bio-based polymer was studied. The experimental results described in this study allow to initiate a first discussion on the role of viscosity and its link with the fracture behaviour and a heterogeneous microstructure such as the semi-crysalline polymer. Dynamic fracture tests on pipes were carried out. It would appear that a temperature decrease of approximately 40℃ relative to ambient has no significant influence on the average crack propagation velocity (≈0.6cR), fracture energy and surface roughness. On the contrary, crack propagation paths seem to vary with temperature. The difference in fracture behaviour between the amorphous and crystalline phase varies significantly as a function of temperature. The difference between the initiation resistance and the rapid propagation also varies. This difference seems to be significantly reduced by lowering the temperature. The mechanisms of cavitation damage and plastic flow are increasingly limited by the decrease in temperature (and therefore in macromolecular mobility). Crack propagation in the pipe is more extensive and therefore more critical. This is emphasised in particular by the probability of the material to be macro-branched as the temperature decreases.

A Kinematics Scalar Projection Method (KSP) for Incompressible Flows with Variable Density

A new scalar projection method presented for simulating incompressible flows with variable density is proposed. It reverses conventional projection algorithm by computing first the irrotational component of the velocity and then the pressure. The first phase of the projection is purely kinematics. The predicted velocity field is subjected to a discrete Hodge-Helmholtz decomposition. The second phase of upgrade of pressure from the density uses Stokes’ theorem to explicitly compute the pressure. If all or part of the boundary conditions is then fixed on the divergence free physical field, the system required to be solved for the scalar potential of velocity becomes a Poisson equation with constant coefficients fitted with Dirichlet conditions.

Improvement of the Viscous Penalty Method for Particle-Resolved Simulations

A numerical study of the parameters controlling the viscous penalty method is investigated to better set up Particle-Resolved Direct Numerical Simulations (PR-DNS) of particulate flows. Based on this analysis, improvements of the methods are proposed in order to reach an almost second order convergence in space. The viscous penalty method is validated in Stokes regime by simulating a uniform flow past a fixed isolated cylinder. Moreover, it is also utilized in moderate Reynolds number regime for a uniform flow past a square configuration of cylinder and compared in terms of friction factor to the well-known Ergun correlation.

Modeling the Interaction between a Thermal Flow and a Liquid: Review and Future Eulerian-Lagrangian Approaches

Suspension Plasma Spraying is a complex process in which several physical mechanisms play a part. So the modeling and understanding of the interaction between a high-velocity and thermal flow and a liquid precursor phase is of major importance concerning the control and characterization of the process. The liquid droplet size distribution has a high influence on the kinetic properties of the as-sprayed nanometer particles before impacting on a target substrate. An overview of existing models is provided dealing with the penetration of the liquid phase into the thermal flame and the resulting fragmentation and vaporization of this phase before impact. The physical characteristics of the flow as well as existing Lagrangian and Eulerian modeling strategies are briefly discussed while paying attention to the physical parameters characterized and measured by numerical simulation. The potential of the various models and also their limits are intended to be highlighted. Future coupled Eulerian-Lagrangian modeling strategies are also proposed for a global and more exhaustive representation of the injection, fragmentation and dispersion part of the two-phase gas-liquid flow before particle impact on the substrate.

Determination of Polyphenols Content in Carob Pulp from Wild and Domesticated Moroccan Trees

Carob (Ceratonia siliqua L.) fruit pulp from 12 wild and 8 domesticated trees from 15 Moroccan localities were investigated for their polyphenols contents: total polyphenols content (53.22 - 118.04 mg and 57.46 - 183.31 mg), total flavonoids (1.41 - 4.83 mg and 1.62 - 7.46 mg) and condensed tannins (1.47 - 7.36 mg and 1.85 - 6.66 mg) in one carob fresh pulp for wild and domesticated trees, respectively. Fruit pulp from trees in the same region shows variable contents in polyphenols, flavonoids and condensed tannins.

Heavy Metals Concentration in Sediments of South Brittany Waters, France: An Ecological Risk Assessment Approach

Distribution patterns of selected heavy metals content in sediments from the Bay of Quiberon and Gulf of Morbihan were studied to understand the current heavy metals contamination due to urbanization and mariculture activities in the coastal area. Therefore, a survey was conducted and 196 sediments collected were characterized for heavy metals content using Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) after mix acid digestion process. The distribution maps of the concentrations of the heavy metals studied were produced as an isopleth map based on data interpolation by the ArcGIS software application. The association with the adverse effects on aquatic organisms was determined by the classification of the sediment according to the sediment quality guidelines. Therefore, two approaches were employed namely: direct comparison with Sediment Quality Guidelines (SQGs) by USEPA (United States Environmental Protection Agency) and comparison with other numerical SQGs, threshold effect level/probable effect level, and effect range low/effect range medium. In order to estimate the effect of multiple contaminations of heavy metals, the mean-ERM-quotient was calculated at each sampling point.

Copy Mean: A New Method to Impute Intermittent Missing Values in Longitudinal Studies

Longitudinal studies are those in which the same variable is repeatedly measured at different times. These studies are more likely than others to suffer from missing values. Since the presence of missing values may have an important impact on statistical analyses, it is important that they should be dealt with properly. In this paper, we present “Copy Mean”, a new method to impute intermittent missing values. We compared its efficiency in eleven imputation methods dedicated to the treatment of missing values in longitudinal data. All these methods were tested on three markedly different real datasets (stationary, increasing, and sinusoidal pattern) with complete data. For each of them, we generated nine types of incomplete datasets that include 10%, 30%, or 50% of missing data using either a Missing Completely at Random, a Missing at Random, or a Missing Not at Random missingness mechanism. Our results show that Copy Mean has a great effectiveness, exceeding or equaling the performance of other methods in almost all configurations. The effectiveness of linear interpolation is highly data-dependent. The Last Occurrence Carried Forward method is strongly discouraged.

Microstructural, Chemical and Mineralogical Analyses for Understanding the Geotechnical Properties of Clayey Soils

This paper presents a study research in the laboratory of three clayey soils from the depression of the Lama, a tropical climate area where disorders appear on construction and roads. Samples were tested to establish the relationship between their mineralogy and their geotechnical properties. On the three clayey soils, analyses were performed to characterize the macroscopic behavior (physical tests, free swelling test and compressibility tests) and the microstructural, chemical and mineralogical characterizations by thermal analysis, chemical analysis, X-Ray diffraction, Scanning Electron Microscopy observations complementary X-ray EDS analyses. At first glance, the results of physical and compressibility tests appear not to be consistent with the free swelling test results. Indeed, these results highlighted differences in the behaviors of the samples because the swelling potential revealed by the results of physical and compressibility test does not follow the same trend as the one given by the free swelling test result. The main clay minerals in the studied clayey soils varied from fibrous clays (palygorskite) to best-known clays such as smectite and kaolinite. Microstructural, chemical and mineralogical analyses allowed to understand and explain the different trends obtained by the different types of geotechnical characterization tests of studied clayey soils.

On a Dual to the Properties of Hurwitz Polynomials I

In this work we develop necessary and sufficient conditions for describing the family of anti-Hurwitz polynomials, introduced by Vergara-Hermosilla et al. in [1]. Specifically, we studied a dual version of the Theorem of Routh-Hurwitz and present explicit criteria for polynomials of low order and derivatives. Another contribution of this work is establishing a dual version of the Hermite-Biehler Theorem. To this aim, we give extensions of the boundary crossing Theorems and a zero exclusion principle for anti-Hurwitz polynomials.

Qualitative Determination of Photodegradation Products of Progesterone and Testosterone in Aqueous Solution

Direct photochemical degradations of progesterone (PR) and testosterone (TR), two naturally produced hormones, have been conducted in non-buffered aqueous solution (pH ranging between 5.5 and 6.0). The irradiation experiments were carried out in a batch reactor upon monochromatic (254 nm) and polychromatic (λ > 290 nm) at 25°C. GLC/MS and LC/UV-DAD/MS analyses were performed to investigate phototransformation products after a solid phase extraction (SPE) step for analytes concentration. For each compound several by-products have been identified and are the same ones under both irradiation conditions. Because of the presence of the same chromophore (α, β-unsaturated group) absorbing UV radiations in both hormones, the majority of chromatographic peaks correspond to by-products formed according to identical mechanisms involving isomerization, enolization, oxidation and hydration to lead to the generation of lumiketone, cyclopentenone, spiro-hydration, oxidation and hydroxylation photoproducts.