Net-zooplankton abundance and biomass from Annaba Bay (SW Mediterranean Sea) under estuarine influences

Zooplankton samples were collected in Annaba Bay (Algeria) from January 2009-March 2011 at three coastal sites differently affected by estuarine plumes and external currents. Aim of this survey was to analyze zooplankton composition, abundance and biomass and compare the results with previous studies to reveal possible populations and environmental changes. The mean zooplankton abundance varied between 1,200-6,000 ind. m-3 and biomass 6.70-25.70 mg DW m-3, according to the site. Copepods constituted the main fraction of zooplankton community, and Oithona similis and Paracalanus indicus successively dominated during autumn-winter and spring-summer. The dinoflagellate Noctiluca scintillans was one of the major zooplankton components, and developed high numbers during February-April, becoming common in neritic and coastal regions. The singularity of the zooplankton from Annaba Bay is the prevalence of P. indicus throughout the entire bay and the decrease in Acartia discaudata and A. clausi (with respect to previous years), possibly replaced by A. negligens. Additionally, Oithona nana abundance markedly decreased with the large development of O. similis. Annaba Bay also differs from other similar Mediterranean coastal areas by the large development of Centropages ponticus populations during the warm period. Among the identified copepod species, the alien species Pseudodiaptomus australiensis and P. arabicus are reported for the first time in the Mediterranean Sea. The occurrence of copepodid V stages of P. australiensis suggests that this species survives and reproduces in Annaba Bay, but so far without developing an abundant population.

Nitrogen Source Differently Regulates Barley (Hordeum vulgare) Response to NaCl Stress At Seed Germination and Early Seedling Development Stages

Nitrogen (N) acts as nutrient and signaling molecule in plants all over their development stages. The involvement of various N forms in the regulation of seed germination response to salt stress was assessed in the present work. Nitrogen sources (NO, NO2−, NO3−, NH4+, glutamine and glutamate) were added at 1mMto the germination medium of barley (Hordeum vulgare, cv Ardhaoui) in combination or not with NaCl stress (14 g.L−1). The application of nitrogen monoxide (NO) alleviated by about 20% the NaCl-induced germination capacity decrease. However, the addition of ammonium ions (NH4+) and glutamic acid (Glu) accentuated the inhibitory effects of NaCl, decreasing germination capacity by about 50% compared to the control. The levels of malondialdehyde (MDA), which is an indicator of membrane lipid peroxidation by stresses, were increased by salinity in seeds treated with nitrite (NO2−), NO3−, Glu and Gln. In N-free medium, NaCl stress induced a severe nitrate reductase activity (NR, EC 1.6.1.6) inhibition. Such an effect was alleviated by the application of N treatments. Glutamate dehydrogenase (GDH, EC 1.4.1.2) aminating activity (NADH-GDH) of seedlings was inhibited by NaCl stress in the presence of NO, Glu and Gln. Conversely, there was stimulation by salt stress of NADH-GDH activity in seedlings treated with NaCl and NH4+. Deaminating GDH activity (NAD-GDH) was found to be enhanced by salt stress in NO2− and NO3− treatments. The differential effects of applied N forms on germination and early seedling development processes in this grass probably underlines different regulatory actions within N mobilization and assimilation

From Disease Association to Risk Assessment: An Optimistic View from Genome-Wide Association Studies on Type 1 Diabetes

Genome-wide association studies (GWAS) have been fruitful in identifying disease susceptibility loci for common and complex diseases. A remaining question is whether we can quantify individual disease risk based on genotype data, in order to facilitate personalized prevention and treatment for complex diseases. Previous studies have typically failed to achieve satisfactory performance, primarily due to the use of only a limited number of confirmed susceptibility loci. Here we propose that sophisticated machine-learning approaches with a large ensemble of markers may improve the performance of disease risk assessment. We applied a Support Vector Machine (SVM) algorithm on a GWAS dataset generated on the Affymetrix genotyping platform for type 1 diabetes (T1D) and optimized a risk assessment model with hundreds of markers. We subsequently tested this model on an independent Illumina-genotyped dataset with imputed genotypes (1,008 cases and 1,000 controls), as well as a separate Affymetrix-genotyped dataset (1,529 cases and 1,458 controls), resulting in area under ROC curve (AUC) of ∼0.84 in both datasets. In contrast, poor performance was achieved when limited to dozens of known susceptibility loci in the SVM model or logistic regression model. Our study suggests that improved disease risk assessment can be achieved by using algorithms that take into account interactions between a large ensemble of markers. We are optimistic that genotype-based disease risk assessment may be feasible for diseases where a notable proportion of the risk has already been captured by SNP arrays

Effet de la couche fenetre sur les performances d’une cellule solaire à base de GaAs

Abstract- During the last years, III-V solar cells were widely used, more particularly in spatial applications, because of their high conversion efficiency and their weak degradation in front of space irradiations. This paper reports on a simulation of a GaAs solar cell using a PC1D. The properties of the top layer in a solar cell (thickness, doping,...) in particular, plays a crucial role in its performances, in order to optimise them we analysed their influence on the Photovoltaic parameters of the cell. To demonstrate the importance of the deposition of a window layer Ga1-xAlxAs on the top of a GaAs solar cell we carried out a comparison of performances between a cell with a window and a conventional GaAs cell (without window). The optimized structure gives the following results: η =26.5% end FF=86.05%. We also compare these cell performances with those of an optimised GaAs single junction solar cell to show the window layer improvement

Optimization of GaInP solar cell performances

In this paper we study a BSF layer structure of a GaInP solar cell and we search for technological parameters of this last leading to its optimized performance (using PC1D simulator). The optimized structure gives the following results: η=19% and FF=85,2%. We also compare these cell performances with those of an optimized GaInP single junction solar cell to show the BSF layer improvement

Nephrolithiasis-induced end stage renal disease

M Ounissi¹, T Gargueh², M Mahfoudhi¹, K Boubaker¹, H Hedri¹, R Goucha¹, E Abderrahim¹, F Ben Hamida¹, T Ben Abdallah¹, F El Younsi¹, H Ben Maiz³, A Kheder¹1Internal Medicine Department, 2Pediatric Department, 3Laboratory of Kidney Diseases, Charles Nicolle Hospital, Tunis, TunisiaIntroduction: Nephrolithiasis still remains a too frequent and underappreciated cause of end stage renal disease (ESRD).Methods and patients: Of the entire cohort of 7128 consecutive patients who started maintenance dialysis in our nephrology department between January 1992 and December 2006, a total of 45 patients (26 women, 19 men) had renal stone disease as the cause of ESRD. The type of nephrolithiasis was determined in 45 cases and etiology in 42. The treatment and evolution of stone disease and patient’s survival were studied.Results: The overall proportion of nephrolithiasis related ESRD was 0.63%. The mean age was 48.4 years. Infection stones (struvite) accounted for 40%, calcium stones, 26.67% (primary hyperparathyroidism:15.56%; familial hypercalciuria: 4.44%, unknown etiology: 6.66%), primary hyperoxaluria type 1, 17.78% and uric acid lithiasis in 15.56% of cases. The mean delay of the evolution of the stone renal disease to chronic renal failure was 85.8 months. The feminine gender, obesity and elevated alkaline phosphatases >128 IU/L were significantly correlated with fast evolution of ESRD. The median evolution to ESRD was 12 months. The normal body mass index (BMI), medical treatment of stone and primary hyperoxaluria type 1 were correlated with fast evolution to ESRD. All patients were treated by hemodialysis during a mean evolution of 60 months. Sixteen patients died. The patient's survival rate at 1, 3 and 5 years was 97.6, 92.8 and 69% respectively. Hypocalcemia, cardiopathy and normal calcium-phosphate product were significantly correlated with lower survival rate.Conclusion: Severe forms of nephrolithiasis remain an underestimated cause of ESRD. These findings highlight the crucial importance of accurate stone analysis and metabolic evaluation to provide early diagnosis and efficient treatment for conditions leading to ESRD.Keywords: Nephrolithoiasis, ESRD, struvite, dialysis, preventio

Variabilité saisonnière et spatiale de la biomasse et de la composition du phytoplancton de la Lagune Mellah (Algérie- Méditerranée)

Le phytoplancton de la lagune Mellah (Algérie) a été étudié à partir d’échantillons de surface prélevés mensuellement d’octobre 2000 à septembre 2001. L’abondance et la biomasse des différentes classes phytoplanctoniques ont été déterminées, ainsi que des caractéristiques physiques du milieu. Les Diatomées sont les plus abondantes et dominent également en nombre d’espèces. L’abondance du phytoplancton varie selon un gradient Nord-Sud qui correspond au gradient de l’influence marine, alors que la biomasse ne suit pas ce schéma en raison de la répartition hétérogène et de la grande taille des espèces de Dinophycées. Ces dernières constituent, par ailleurs, avec les Diatomées l’essentiel de la biomasse phytoplanctonique (55 à 92 %). La biomasse phytoplanctonique est importante tout au long de l’année (4 - 173 μg C.L-1) et elle augmente du simple au triple selon un gradient d’éloignement par rapport au chenal de communication avec la Méditerranée.Mots clés: phytoplancton; biomasse; Dinophycées; Diatomées; lagune Mellah; Algérie, Méditerranée

Prévalence et facteurs de risque de la dysfonction érectile chez les insuffisants rénaux chroniques

Objectif: dépister la dysfonction érectile (DE) chez les insuffisants rénaux chroniques (IRC) et déterminer ses facteurs de risque. Patients et méthodes: Etude transversale auprès de 30 patients suivis pour une IRC. Tous les patients ont fait l’objet d’un dépistage de la dysfonction érectile à l’aide de l’indice international de la fonction érectile (IIEF-5). Résultats: L’âge moyen de nos patients était de 49,6 ± 9 ans. Le score IIEF moyen était de 15,62 ± 6,03. Le diagnostic de DE a été retenu chez 23 patients (76,7%). La prévalence de la DE était significativement plus élevée chez les insuffisants rénaux au stade terminal (89,5%) que chez ceux aux stades 3 et 4 (54,5%) (p=0,04). L’âge ≥ 50 ans, le tabagisme, le diabète, l’HTA, la dyslipidémie, l’obésité ou le surpoids, l’artériopathie distale, l’anémie ont été retrouvés respectivement dans 60,9%, 73,9%, 43,5%, 78,3%, 75%, 60,9%, 30,4% et 82,6% des cas. L’analyse statistique a montré que le tabagisme (OR = 17 ; IC : [1,68-171,7] ; p = 0,009), le stade terminal de l’IRC (OR =7,08 ; IC 95%: [1,07-46,67] ; p = 0,04) et l’HDLc bas (OR = 18 ; IC 95%: [1,19-271,46] ; p = 0,04) étaient les seuls facteurs de risque de la DE chez nos patients. Conclusions: La prévalence élevée de la DE et la multiplicité des facteurs de risque sont une nouvelle illustration de la gravité de ce trouble sexuel chez les insuffisants rénaux chronique

Theoretical evaluation of the antioxidant activity of some stilbenes using the Density Functional Theory

In this paper, the antiradical potential of trans-2,4,3′,5′-tetrahydroxystilbene (T-OXY), trans-2,3′,4-trihydroxystilbene (T-RES), cis-2,4,1′,3′-tetrahydroxystilbene (C-OXY) and cis-2,1′,4-trihydroxystilbene (C-RES) is investigated by BDE (E0) and ETS-NOCV calculations, in water, benzene, DMSO, and ethanol. The study of solubility by the COSMO-RS model demonstrates that the compounds are very soluble in DMSO. The hydrogen atom transfer (HAT), sequential proton loss electron transfer (SPLET), and single electron transfer followed by proton transfer (SET-PT) mechanisms are explored as possible oxidation paths of these compounds using the DFT calculations at B3LYP/6-311++G(2d,2p) level of theory in DMSO. For all the studied compounds, the HAT was found to be the thermodynamically dominant mechanism, indicating that the investigated compounds can be classified according to their antiradical activity in the following sequence order T-OXY˃T-RES˃C-OXY˃C-RES. The evaluation of ΔHBDE reaction enthalpies, ΔHIP, and ΔHPA linked to the three mechanisms with certain radicals (HO·, HOO·, CH3O· and CH3OO·, NO·, and NO2·) are determined. The results indicate the HAT and SPLET mechanisms are competitive in inhibiting those species. QTAIM calculations reveal the existence of critical points in the two conformers. The Diels-Alder intramolecular cyclization of (C-OXY) leads to two new tautomers: trans-cycle-OXY (T-CYCLE-OXY) and cis-cycle-OXY (C-CYCLE-OXY) with a significant improvement in the antioxidant activity. In conclusion, T-OXY and T-CYCLE-OXY are identified as the best antioxidant candidates among those tested