INFLUENCE DU TRAITEMENT THERMIQUE ET MECANIQUE SUR LES PROPRIETES MECANIQUES ET STRUCTURALES DES ACIERS AU MANGANESE MOULES.

Molded Steel with manganese have approximately 1,2% C and 12% Mn, this high proportion of manganese gives to this alloy a stable austenitic structure on a room temperature. The experimental methods used for metallurgical studies are spark optical emission spectroscopy, optical microscopy, scanning electron microscopy, micro-hardness and hardnesss test. Steel 1 is heat-treated constitued by 15,516 % of manganese, 2,677 % of chromuim and 1,286 % of carbon. Steel 2 is mechanically treated contains 13,454 % of manganese, 1,721 % of chromuim and 1,213 % of carbon . Steel 1 has sustained quench at 1070°C, for two differents maintaining times on oven 30 and 50 minutes for a thickness of 150 millimeters then for two differents thickness 100 and 150 millimeters for a time of 50 minutes. When maintaining time on the oven increase for low dimension, surface’s alloy become more ductile. We have applied a mechanical treatement manually on steel 2 surface, his hardness increase significantly

MODELISATION DE L'INFLUENCE DU TRAITEMENT THERMIQUE SUR LES PROPRIETES MECANIQUES DES ALLIAGES ALUMINIUM-CUIVRE (Al-Cu)

In order to master and improve the quality and properties of the final products, the major industrial challenge lies in the possibility of controlling the morphology, size of microstructures that reside within the molded pieces, as well as their defects; this is the fundamental reason according to which we are more and more interested in mastering the growth and germination of such alloys, as well as the developing structures, at the time of solidification process. The modeling reveals as a valuable aid in the mastery of the formation of such heterogeneousness: segregation cells that are incompatible with industrial requirements. The whole work focuses upon the modeling of the segregation phenomenon of the four hypoeutectic alloys, Al1%Cu, Al2%Cu, Al3%Cu et Al4%Cu, as well as the copper effect upon certain mechanical properties of aluminum. Usually, the microstructure and mechanical behavior of such alloys as Al-Cu are directly influenced by some parameters such as composition, cooling velocity and homogenization process

Serum relaxin levels are reduced in pregnant women with a history of recurrent miscarriage, and correlate with maternal uterine artery Doppler indices in first trimester

Objectives: Defective implantation is a mechanism for recurrent pregnancy loss (RPL). We sought to determine whether the serum expression of human relaxin-2 (RLX) is impaired in women with a history of RPL. Study design: Employing a prospective case-controlled design we studied 20 pregnant women with a history of RPL and 20 age-matched women with no history of RPL (NRPL). We measured serum relaxin-2 levels by ELISA at 6-8. 10-12, 20, and 34 weeks gestation and in cord blood, and maternal uterine artery Doppler resistance index (RI) at >= 10 weeks gestation. Results: Relaxin rose to a peak at 12 weeks, and gradually declined towards term. At all gestations, women with a history of RPL had lower RLX levels than women without. At 10-12 weeks gestation, uterine artery RI correlated with serum RLX for both RPL and NRPL. In the NRPL group at 10-12 weeks the presence of a notched waveform was associated with higher RLX levels than the absence of a notch (mean 2.1 ng/ml vs. 1.3 ng/ml, P < 0.05) and also at 20 weeks (2.1 ng/ml vs. 0.95 ng/ml, P < 0.05) but no such difference was seen in the RPL group. Umbilical venous RLX was 4-fold higher in the RPL group than the NRPL group. Conclusion: Women with a history of RPL demonstrate attenuated levels of serum RLX across all pregnancy trimesters. How dysregulated RLX metabolism may contribute to adverse pregnancy outcome in RPL requires further investigation. Crown Copyright (C) 2009 Published by Elsevier Ireland Ltd. All rights reserved

Simplified molecular detection of Leishmania parasites in various clinical samples from patients with leishmaniasis

<p>Abstract</p> <p>Background</p> <p>Molecular methods to detect <it>Leishmania </it>parasites are considered specific and sensitive, but often not applied in endemic areas of developing countries due to technical complexity. In the present study isothermal, nucleic acid sequence based amplification (NASBA) was coupled to oligochromatography (OC) to develop a simplified detection method for the diagnosis of leishmaniasis. NASBA-OC, detecting <it>Leishmania </it>RNA, was evaluated using clinical samples from visceral leishmaniasis patients from East Africa (n = 30) and cutaneous leishmaniasis from South America (n = 70) and appropriate control samples.</p> <p>Results</p> <p>Analytical sensitivity was 10 parasites/ml of spiked blood, and 1 parasite/ml of culture. Diagnostic sensitivity of NASBA-OC was 93.3% (95% CI: 76.5%-98.8%) and specificity was 100% (95% CI: 91.1%-100%) on blood samples, while sensitivity and specificity on skin biopsy samples was 98.6% (95% CI: 91.2%-99.9%) and 100% (95% CI: 46.3%-100%), respectively.</p> <p>Conclusion</p> <p>The NASBA-OC format brings implementation of molecular diagnosis of leishmaniasis in resource poor countries one step closer.</p

Concurrent Acquisition of a Single Nucleotide Polymorphism in Diverse Influenza H5N1 Clade 2.2 Sub-clades

Highly pathogenic Influenza A H5N1 was first identified in Guangdong Province in 1996, followed by human cases in Hong Kong in 1997. The number of confirmed human cases now exceeds 300, and the associated Case Fatality Rate exceeds 60%. The genetic diversity of the serotype continues to increase. Four distinct clades or sub-clades have been linked to human cases. The gradual genetic changes identified in the sub-clades have been attributed to copy errors by viral encoded polymerases that lack an editing function, thereby resulting in antigenic drift. We report here the concurrent acquisition of the same polymorphism by multiple, genetically distinct, clade 2.2 sub-clades in Egypt, Russia, and Ghana. These changes are not easily explained by the current theory of &#x201c;random mutation&#x201d; through copy error, and are more easily explained by recombination with a common source. This conclusion is supported by additional polymorphisms shared by clade 2.2 isolates in Egypt and Germany

Aggregation of Single Nucleotide Polymorphisms in a Human H5N1 Clade 2.2 Hemagglutinin

The evolution of H5N1 has attracted significant interest 1-4 due to linkages with avian 5,6 and human infections 7,8. The basic tenets of influenza genetics 9 attribute genetic drift to replication errors caused by a polymerase complex that lacks a proof reading function. However, recent analysis 10 of swine influenza genes identifies regions copied with absolute fidelity for more than 25 years. In addition, polymorphism tracing of clade 2.2 H5N1 single nucleotide polymorphisms identify concurrent acquisition 11 of the same polymorphism onto multiple genetic backgrounds in widely dispersed geographical locations. Here we show the aggregation of regional clade 2.2 polymorphisms from Germany, Egypt, and sub-Sahara Africa onto a human Nigerian H5N1 hemagglutinin (HA), implicating recombination in the dispersal and aggregation of single nucleotide polymorphisms from closely related genomes

An evaluation of existent methods for estimation of embankment dam breach parameters

The study of dam-break analysis is considered important to predict the peak discharge during dam failure. This is essential to assess economic, social and environmental impacts downstream and to prepare the emergency response plan. Dam breach parameters such as breach width, breach height and breach formation time are the key variables to estimate the peak discharge during dam break. This study presents the evaluation of existing methods for estimation of dam breach parameters. Since all of these methods adopt regression analysis, uncertainty analysis of these methods becomes necessary to assess their performance. Uncertainty was performed using the data of more than 140 case studies of past recorded failures of dams, collected from different sources in the literature. The accuracy of the existing methods was tested, and the values of mean absolute relative error were found to be ranging from 0.39 to 1.05 for dam breach width estimation and from 0.6 to 0.8 for dam failure time estimation. In this study, artificial neural network (ANN) was recommended as an alternate method for estimation of dam breach parameters. The ANN method is proposed due to its accurate prediction when it was applied to similar other cases in water resources

Aggregation of Single Nucleotide Polymorphisms in a Human H5N1 Clade 2.2 Hemagglutinin

The rapid evolution of the H5N1 serotype of avian influenza has been explained by a mechanism involving the selection of single nucleotide polymorphisms generated by copy errors. The recent emergence of H5N1 Clade 2.2 in fifty countries, offered a unique opportunity to view the acquisition of new polymorphism in these evolving genomes. We analyzed the H5N1 hemagglutinin gene from a fatal human case from Nigeria in 2007. The newly emerged polymorphisms were present in diverse H5N1 isolates from the previous year. The aggregation of these polymorphisms from clade 2.2 sub-clades was not supported by recent random mutations, and was most easily explained by recombination between closely related sequences

Prevalence and correlates of autism spectrum disorder in Qatar: a national study

Background Few epidemiological data on autism spectrum disorders (ASD) exist for Arabic countries. We conducted the first survey of ASD in Qatar, a population with high consanguinity level. Methods This cross‐sectional survey was conducted from 2015 to 2018 in Qatar school‐age children (N = 176,960) from national and immigrant families. Children diagnosed with ASD were identified through medical centers and special needs schools. Records were abstracted and supplemented by parental interviews. Additionally, children attending 93 schools were screened; ASD case status was confirmed in random samples of screen‐positive and screen‐negative children. Prevalence was estimated after taking into account different sampling fractions and participation rates at each survey phase. Results One thousand three hundred and ninety‐three children already diagnosed with ASD were identified. Among 9,074 school survey participants, 760 screen‐negative children and 163 screen‐positive children were evaluated; 17 were confirmed to have ASD including five children newly diagnosed. Prevalence was 1.14% (95% CI: 0.89–1.46) among 6‐ to 11‐year‐olds. ASD was reported in full siblings/extended relatives in 5.9% (95% CI: 0.042–0.080)/11.8% (95% CI: 0.095–0.146) families. First‐degree consanguinity in Qatari cases (45%) was comparable to known population levels. Among 844 ASD cases (mean age: 7.2 years; 81% male), most children experienced language delay (words: 75.1%; phrase speech: 91.4%), and 19.4% reported developmental regression. At the time of the survey, persisting deficits in expressive language (19.4%) and peer interactions (14.0%) were reported in conjunction with behavioral problems (ADHD: 30.2%; anxiety: 11.0%). In multivariate logistic regression, ASD severity was associated with parental consanguinity, gestational diabetes, delay in walking, and developmental regression. Conclusions ASD prevalence in Qatar is consistent with recent international studies. The methods employed in this study should help designing comparable surveys in the region. We estimated that 187,000 youths under age 20 have ASD in Gulf countries. This figure should assist in planning health and educational services for a young, fast‐growing population.The study was supported by the Qatar National Research Fund. The sponsor had no role in the design and conduct of the study, or the collection, management, analysis, and interpretation of the data, or in the preparation, review, or approval of the manuscript, and in the decision to submit the manuscript for publication. The authors thank all the independent and private schools that have participated in the SCQ screening phase. The authors thank the Ministry of Public Health and the Ministry of Education for providing their team with the data required throughout the study. The authors would like to express our gratitude to the psychological services team at the Shafallah Center for Children with Disabilities, as well as Dr. Irshad Shafeullah and Dr. Zakariah Al-Sayed for their support in patient recruitment. The authors also thank our colleagues from QBRI: Dr. Hatem Al-Shanti for his assistance in patient phenotyping, and Mr. Yasser Al-Sarraj and Ms. Hamda AlMutawwa for their support with patient recruitment. The authors thank Dr. Hanaa Massoud for assisting with patient recruitment through the clinic at the Child Development Center in Rumailah Hospital. The authors would also like to express their appreciation to the QBRI administration team for their assistance with planning and logistics pertaining to research-related training sessions and research collaborator visits. Additionally, the authors would like to thank all of the special needs centers and clinics which collaborated with us to provide data needed for the high probability cases; Shafallah Center for Children with Disabilities, Hamad Medical Corporation, Child Development Center ? Rumailah Hospital, Child Development Center-Private, Renad Academy, Al-Tamakun school, Step by Step Center, Qatar Institute for Speech and Hearing, and Hope Center. The authors also thank the HBKU Sponsored Research Office for the support provided throughout the research funding period.?K.R. and the OHSU Biostatistics & Design Program was partially supported by the Oregon Clinical and Translational Research Institute (OCTRI) through OHSU Clinical & Translational Science Awards (CTSA UL1TR0002369) National Consortium. The authors are immensely grateful to the families and their children for their time and participation in any of the phases of the research. F.A. and E.F. designed the research plan. F.A., M.A., and E.F. applied for funding. F.A., H.A., S.E., I.G., M.T., M.A., M.K., N.A.A., M.A., A.H.S., and L.D. organized the data collection. F.A., H.A., S.E., and I.G. completed data entry and cleaning, and performed initial data analyses with M.A. E.F. performed data and statistical analyses. K.R. provided biostatistical advice. E.F., F.A., and I.G. wrote the manuscript. All authors reviewed and approved the manuscript. The authors have declared that they have no competing or potential conflicts of interest.Scopu