Observation of superspin glass state in magnetically textured ferrofluid (gamma-Fe2O3)

Magnetic properties in a magnetically textured ferrofluid made out of interacting maghemite (gamma-Fe2O3) nanoparticles suspended in glycerin have been investigated. Despite the loss of uniform distribution of anisotropy axes, a superspin glass state exists at low temperature in a concentrated, textured ferrofluid as in the case of its non-textured counterpart. The onset of superspin glass state was verified from the sample's AC susceptibility. The influence of the anisotropy axis orientation on the aging behavior in the glassy states is also discussed

Measurement of the extent of strain relief in InGaAs layers grown under tensile strain on InP(100) substrates

International audienceHigh resolution x‐ray diffraction has been used to investigate the structural properties of InxGa1−xAs epitaxial layers grown under tension on InP(100) substrates. The nominal indium composition (x=0.42) corresponds to a small lattice mismatch and a two dimensional growth mode. We have also included for comparison two samples grown under compression covering the mostly strained and the mostly relaxed regimes. Our results show that the residual strain and the asymmetry in strain relaxation along 〈011〉 directions are always larger for layers under tension. This can be explained by the difference in dislocation glide velocity induced by a different indium content, by the dissociation of perfect dislocations and partially by the difference in thermal expansion coefficients between substrate and epilayer. The larger asymmetry in strain relaxation for tensile strain layers is interpreted by the existence of microcracks aligned in the [011] direction

Exceptional quantum subgroups for the rank two Lie algebras B2 and G2

Exceptional modular invariants for the Lie algebras B2 (at levels 2,3,7,12) and G2 (at levels 3,4) can be obtained from conformal embeddings. We determine the associated alge bras of quantum symmetries and discover or recover, as a by-product, the graphs describing exceptional quantum subgroups of type B2 or G2 which encode their module structure over the associated fusion category. Global dimensions are given.Comment: 33 pages, 27 color figure

Teneurs de métaux traces dans des sols à maraîchers dans la ville d’Abidjan (Côte d’Ivoire)

L’objectif principal de cette étude est l’évaluation de l’état de contamination en métaux traces de sols cultivés dans la ville d’Abidjan. Pour ce faire, des sols ont été prélevés dans des fosses pédologiques sur les sites maraîchers de Marcory et Cocody et sur la ferme expérimentale de l’Université d’Abobo-Adjamé. L’analyse des échantillons a révélé que sur les 3 sites, la quasi-totalité des horizons sont sableux, acides, riches en Mn et Fe. Les teneurs en Cd à Marcory et à Cocody, la teneur en Cu à Marcory, les teneurs en Pb à Cocody et sur la parcelle expérimentale, les teneurs en Zn sur les 3 sites, et les teneurs en Ni à Marcory et à Cocody, sont supérieures aux teneurs limites recommandées. L’acidité et la forte macroporosité des sols ont favorisé lamigration verticale des métaux traces.Mots clés: métaux traces, sols à maraîchers, Abidjan, migratio

Superspin glass aging behavior in textured and nontextured frozen ferrofluid

The effect of magnetic anisotropy-axis alignment of individual nanoparticles on the collective aging behavior in the superspin glass state of a frozen ferrofluid has been investigated. The ferrofluid studied here consists of maghemite nanoparticles (\gamma-Fe2O3, mean diameter = 8.6 nm) dispersed in glycerin at a volume fraction of ~15%. The low temperature aging behavior has been explored through 'zero-field cooled magnetization' (ZFCM) relaxation measurements using SQUID magnetometry. The ZFCM response functions were found to scale with effective age of the system in both textured and non-textured superspin glass states, but with markedly different scaling exponents, \mu. The value of {\mu} was found to shift from ~0.9 in non-textured case to ~ 0.6 in the textured case, despite the identical cooling protocol used in both experiments

Renal oncocytoma: experience of Clinical Urology A, Urology Department, CHU Ibn Sina, Rabat, Morocco and literature review

Renal oncocytoma is a rare and benign renal tumor. Only few cases have been reported in Moroccan populations. In the present study, we reportour experiences in the diagnosis, management and follow-up of this disease. We report on six cases of renal oncocytoma indentified between 1990 and 2008 in the urology department of “CHU Ibn Sina” in Rabat. These six cases are listed among 130 kidney tumors reported during the study period. We assess the clinical, radiological and therapeutic features of the patients and we review literature. Six cases of renal oncocytoma,representing 4.6% of all primitive kidney tumors treated in our institution during the study period. The mean age was 53 ±9.7 years (range 34 to61 years). One patient was asymptomatic at presentation, five patients (83%) had flank pain and two (33%) had macroscopic hematuria. Thetumor was right sided in 4 cases (66%) and left sided in 2 cases (33%). All patients underwent CT scan which showed, in three cases, a centrallylocated stellate area of low attenuation. The clinical suspicion of  oncocytoma was made preoperatively in only 3 patients by imaging studies, but the suspicion of renal cell carcinoma persist and all patients were treated with radical nephrectomy. Definitive diagnosis was made in all cases postoperatively. All the tumors were well circumscribed but unencapsulated. The mean tumor size was 8,75±2,04 cm. Four patients were classified at stage pT2 and two at stage p T1. Most of the pathological features in our patients were typical of this entity.  Predominant cell type was a typical oncocytoma with general low mitotic activity. No extension to peri-nephric fat tissue or lymphovascular invasion was observed. After a mean follow-up of 36 months (range 26-62 months), there was neither recurrence nor death from oncocytoma. Accordingly, the disease-specific survival was 100%. Renal oncocytoma has a benign clinical course with excellent long-term outcomes. In our series, it happened mostly in females and is more frequently symptomatic. Although radical nephrectomy is the usual treatment, a conservative approach should be considered whenever there are signs of clinical and radiological presumptions.Key words: Renal oncocytoma, tumor, diagnosis, treatmen

Introduction à la pollution atmosphérique dans la ville de Meknès : dioxyde de soufre, ozone et matière particulaire en suspension

In this work, we were interested in a preliminary evaluation of air quality in the town of Meknes, in particular, the measurement of sulphur dioxide (SO2), ozone (O3) and the particulate matter in suspension (PM-10) whose particles have a diameter lower than 10 µm, with separation of the fractions according to the size: fine fractions (diameter lower or equalizes with 2.5 µg/m3) and coarse fractions (diameter between 2.5 µg/m3 and 10 µg/m3). The samples were collected one day in (July, October and November 2005) in several sites (urban, suburban, proximity,…). The mesures of the gaseous pollutants (SO2 and O3) were realized on the site every 15 min. by automatic analyzers (AF21M and O341M). Whereas, PM-10 were collected respectively by Dichotomous and the Gent samplers. The chemical and mineral composition of the PM-10 was determined by various techniques of physicochemical analyses: Atomic Absorption Spectrometer (SAA), X-ray Fluorescence in Total Reflection (TXRF), Scanning Electron Microscope coupled with Energy Dispersion Spectrometer (SEM-EDS) and X-Rays Diffraction (XRD).Dans ce travail, nous nous sommes intéressés à une évaluation préliminaire de la qualité de l’air dans la ville de Meknès, en particulier la mesure du dioxyde de soufre (SO2), de l’ozone (O3) et de la matière particulaire en suspension (PM-10) dont les particules ont un diamètre inférieur à 10 µm avec séparation des fractions en fonction de la taille : fractions fines (diamètre inférieur ou égale à 2,5 µg/m3) et fractions grossières (diamètre entre 2,5 µg/m3 et 10 µg/m3). Pour cela, nous avons mené trois campagnes de prélèvements journalières en (juillet, octobre et novembre 2005) dans plusieurs sites (urbain, suburbain, proximité, fond). Les mesures des polluants gazeux (SO2 et O3) ont été effectuées sur terrain, tout les quart d’heures  par des analyseurs automatiques (AF21M et O341M). Alors que pour les PM-10, le prélèvement a été réalisé respectivement par le Dichotomous et le Gent. La composition chimique et minérale des PM-10 a été déterminée par différentes techniques d’analyses physico-chimiques : Spectromètre d’Absorption Atomique (SAA), Fluorescence X en Réflexion Totale (FXRT), Microscope Electronique à Balayage couplé au Spectromètre à Dispersion d’Energie (MEB-SDE) et Diffraction des Rayons X (DRX)

Clique-Finding for Heterogeneity and Multidimensionality in Biomarker Epidemiology Research: The CHAMBER Algorithm

Commonly-occurring disease etiology may involve complex combinations of genes and exposures resulting in etiologic heterogeneity. We present a computational algorithm that employs clique-finding for heterogeneity and multidimensionality in biomedical and epidemiological research (the "CHAMBER" algorithm).This algorithm uses graph-building to (1) identify genetic variants that influence disease risk and (2) predict individuals at risk for disease based on inherited genotype. We use a set-covering algorithm to identify optimal cliques and a Boolean function that identifies etiologically heterogeneous groups of individuals. We evaluated this approach using simulated case-control genotype-disease associations involving two- and four-gene patterns. The CHAMBER algorithm correctly identified these simulated etiologies. We also used two population-based case-control studies of breast and endometrial cancer in African American and Caucasian women considering data on genotypes involved in steroid hormone metabolism. We identified novel patterns in both cancer sites that involved genes that sulfate or glucuronidate estrogens or catecholestrogens. These associations were consistent with the hypothesized biological functions of these genes. We also identified cliques representing the joint effect of multiple candidate genes in all groups, suggesting the existence of biologically plausible combinations of hormone metabolism genes in both breast and endometrial cancer in both races.The CHAMBER algorithm may have utility in exploring the multifactorial etiology and etiologic heterogeneity in complex disease

Meta-analysis of four new genome scans for lipid parameters and analysis of positional candidates in positive linkage regions

Lipid levels in plasma strongly influence the risk for coronary heart disease. To localise and subsequently identify genes affecting lipid levels, we performed four genome-wide linkage scans followed by combined linkage/association analysis. Genome-scans were performed in 701 dizygotic twin pairs from four samples with data on plasma levels of HDL- and LDL-cholesterol and their major protein constituents, apolipoprotein AI (ApoAI) and Apolipoprotein B (ApoB). To maximise power, the genome scans were analysed simultaneously using a well-established meta-analysis method that was newly applied to linkage analysis. Overall LOD scores were estimated using the means of the sample-specific quantitative trait locus (QTL) effects inversely weighted by the standard errors obtained using an inverse regression method. Possible heterogeneity was accounted for with a random effects model. Suggestive linkage for HDL-C was observed on 8p23.1 and 12q21.2 and for ApoAI on 1q21.3. For LDL-C and ApoB, linkage regions frequently coincided (2p24.1, 2q32.1, 19p13.2 and 19q13.31). Six of the putative QTLs replicated previous findings. After fine mapping, three maximum LOD scores mapped within 1cM of major candidate genes, namely APOB (LOD =2.1), LDLR (LOD =1.9) and APOE (LOD =1.7). APOB haplotypes explained 27% of the QTL effect observed for LDL-C on 2p24.1 and reduced the LOD-score by 0.82. Accounting for the effect of the LDLR and APOE haplotypes did not change the LOD score close to the LDLR gene but abolished the linkage signal at the APOE gene. In conclusion, application of a new meta-analysis approach maximised the power to detect QTLs for lipid levels and improved the precision of their location estimate. © 2005 Nature Publishing Group. All rights reserved