Effect of FSW Parameters on The Microstructure and Mechanical Properties of T-joints between Dissimilar Al-Alloys

The main purpose of this research is to develop T-joints between the aluminum AA 2024-T4 and AA 7075-T6 using friction stir welding.  The effect of tool geometries, tool traveling speed, and rotational rate in the welded T-joints were investigated and discussed. Three different tools were used with different shoulder to pin ratios 3.28, 3.36, and 4.31. After optimization, the best tool dimension has used with the different rotational and welding speeds. Three tool traverse speeds of 50, 75, and 100 mm/min were used. Two rotation rates of 800 rpm and 1000 rpm were applied. After FSW, at a number of the above FSW parameters' combinations, macrostructure and microstructure analyses were done using optical microscopy. In order to have an insight into the mechanical properties, hardness measurements and tensile testing were carried out. Using small shoulder to pin ratio produced visually unacceptable T-joint. Opposite happened by using the tool with 4.31 of shoulder to pin ratio. Furthermore, the results showed sound T-welds with no obvious defects at high rotational rate of 1000 rpm with the two used traveling speeds. Asymmetric temperature distribution was observed between the two sides, advance side (AS) and retreating side (RS

Effects of ammonia toxicity on growth performance, cortisol, glucose and hematological response of Nile Tilapia (Oreochromis niloticus)

Ammonia is a production limiting factor in the aquaculture media affecting fish production. A study was designed to scrutinize effects of ammonia on growth performance, survival, cortisol and hematological parameters of Tilapia fish. The study examined effects of 96 h-incubation of male and female Tilapia with 3 mg ammonium chloride per a liter of water compared to control. The study has been carried out in the physiology laboratory of the department of animal and fish production, Alexandria University. Fourteen aquaria were used (6 control and 8 ammoniated). Each aquarium contained 6 fish (half the population males and the other have females). Duration of the control reared fish was 30 days, however the duration for ammoniated group was 4 days. In all stressed fish, there found decreases in final body weight, average daily gain and specific growth rate as compared to controls. Hematological parameters revealed increases (P0.05) in total leukocyte counts in both males and females exposed to stressors. There were significant decreases (P0.05) in red blood cell, hematocrit value and hemoglobin concentration in both males and females. There were non-significant differences (P0.10) in these parameters between males and females. Exposing both male and female tilapia to ammonia, resulted in increases (P0.05) in mean corpuscular volume (MCV). Mean corpuscular hemoglobin (MCH) didn’t change in male tilapia, while females expressed increased MCH values in the ammonia condition. Mean corpuscular hemoglobin concentration (MCHC) decreased (P0.05) under ammonia with no differences between males and females. Differential leukocyte count exhibited increases (P0.05) in neutrophils in ammonia-exposed males and females and decreases (P0.05) in eosinophils and monocytes in males, but not in females. However, lymphocytes decreased (P0.05) in both females and males exposed to ammonia. Cortisol level increased (P0.05) by about 2 folds in both sexes of fish exposed to ammonia (2.95 and 2.72 vs6.40 and 6.48 ng/ml in control males and females vs ammonia-exposed males and females).Rearing tilapia fish in media containing high level (3mg/l water) of ammonium chloride not only deteriorated growth rate but it also negatively affected the health wellbeing.

Molecular identification of adenoviruses associated with respiratory infection in Egypt from 2003 to 2010.

BACKGROUND: Human adenoviruses of species B, C, and E (HAdV-B, -C, -E) are frequent causative agents of acute respiratory infections worldwide. As part of a surveillance program aimed at identifying the etiology of influenza-like illness (ILI) in Egypt, we characterized 105 adenovirus isolates from clinical samples collected between 2003 and 2010. METHODS: Identification of the isolates as HAdV was accomplished by an immunofluorescence assay (IFA) and confirmed by a set of species and type specific polymerase chain reactions (PCR). RESULTS: Of the 105 isolates, 42% were identified as belonging to HAdV-B, 60% as HAdV-C, and 1% as HAdV-E. We identified a total of six co-infections by PCR, of which five were HAdV-B/HAdV-C co-infections, and one was a co-infection of two HAdV-C types: HAdV-5/HAdV-6. Molecular typing by PCR enabled the identification of eight genotypes of human adenoviruses; HAdV-3 (n = 22), HAdV-7 (n = 14), HAdV-11 (n = 8), HAdV-1 (n = 22), HAdV-2 (20), HAdV-5 (n = 15), HAdV-6 (n = 3) and HAdV-4 (n = 1). The most abundant species in the characterized collection of isolates was HAdV-C, which is concordant with existing data for worldwide epidemiology of HAdV respiratory infections. CONCLUSIONS: We identified three species, HAdV-B, -C and -E, among patients with ILI over the course of 7 years in Egypt, with at least eight diverse types circulating

Epigenetic modifiers induce bioactive phenolic metabolites in the marine-derived fungus penicillium brevicompactum

Fungi usually contain gene clusters that are silent or cryptic under normal laboratory culture conditions. These cryptic genes could be expressed for a wide variety of bioactive compounds. One of the recent approaches to induce production of such cryptic fungal metabolites is to use histone deacetylases (HDACs) inhibitors. In the present study, the cultures of the marine-derived fungus Penicillium brevicompactum treated with nicotinamide and sodium butyrate were found to produce a lot of phenolic compounds. Nicotinamide treatment resulted in the isolation and identification of nine compounds 1–9. Sodium butyrate also enhanced the productivity of anthranilic acid (10) and ergosterol peroxide (11). The antioxidant as well as the antiproliferative activities of each metabolite were determined. Syringic acid (4), sinapic acid (5), and acetosyringone (6) exhibited potent in vitro free radical scavenging, (IC50 20 to 30 µg/mL) and antiproliferative activities (IC50 1.14 to 1.71 µM) against HepG2 cancer cell line. Furthermore, a pharmacophore model of the active compounds was generated to build up a structure-activity relationship

A Randomized Open-Label Trial of Artesunate- Sulfadoxine-Pyrimethamine with or without Primaquine for Elimination of Sub-Microscopic P. falciparum Parasitaemia and Gametocyte Carriage in Eastern Sudan

In areas of seasonal malaria transmission, treatment of asymptomatic carriers of malaria parasites, whose parasitaemia persists at low densities throughout the dry season, could be a useful strategy for malaria control. We carried out a randomized trial to compare two drug regimens for clearance of parasitaemia in order to identify the optimum regimen for use in mass drug administration in the dry season.A two-arm open-label randomized controlled trial was conducted during the dry season in an area of distinct seasonal malaria in two villages in Gedarif State in eastern Sudan. Participants were asymptomatic adults and children aged over 6 months, with low-density P. falciparum infection detected by PCR. Participants were randomized to receive artesunate/sulfadoxine-pyrimethamine (AS+SP) combination for three days with or without a dose of primaquine (PQ) on the fourth day. Parasitaemia detected by PCR on days 3, 7 and 14 after the start of treatment and gametocytes detected by RT-PCR on days 7 and 14 were then recorded. 104 individuals who had low density parasitaemia at screening were randomized and treated during the dry season. On day 7, 8.3% were positive by PCR in the AS+SP+PQ group and 6.5% in the AS+SP group (risk difference 1.8%, 95%CI -10.3% to +13.8%). At enrolment, 12% (12/100) were carrying gametocytes. This was reduced to 6.4% and 4.4% by day 14 (Risk difference 1.9% (95%CI -9.3% to +13.2%) in AS+SP+PQ and AS+SP groups, respectively.Addition of primaquine to artemisinin combination treatment did not improve elimination of parasitaemia and prevention of gametocyte carriage in carriers with low-density parasitaemia in the dry season.ClinicalTrials.gov NCT00330902

Direct susceptibility testing for multi drug resistant tuberculosis: A meta-analysis

<p>Abstract</p> <p>Background</p> <p>One of the challenges facing the tuberculosis (TB) control programmes in resource-limited settings is lack of rapid techniques for detection of drug resistant TB, particularly multi drug resistant tuberculosis (MDR TB). Results obtained with the conventional indirect susceptibility testing methods come too late to influence a timely decision on patient management. More rapid tests directly applied on sputum samples are needed. This study compared the sensitivity, specificity and time to results of four direct drug susceptibility testing tests with the conventional indirect testing for detection of resistance to rifampicin and isoniazid in <it>M. tuberculosis</it>. The four direct tests included two in-house phenotypic assays – Nitrate Reductase Assay (NRA) and Microscopic Observation Drug Susceptibility (MODS), and two commercially available tests – Genotype^®MTBDR and Genotype^®MTBDR<it>plus </it>(Hain Life Sciences, Nehren, Germany).</p> <p>Methods</p> <p>A literature review and meta-analysis of study reports was performed. The Meta-Disc software was used to analyse the reports and tests for sensitivity, specificity, and area under the summary receiver operating characteristic (sROC) curves. Heterogeneity in accuracy estimates was tested with the Spearman correlation coefficient and Chi-square.</p> <p>Results</p> <p>Eighteen direct DST reports were analysed: NRA – 4, MODS- 6, Genotype MTBDR^®– 3 and Genotype^®MTBDR<it>plus </it>– 5. The pooled sensitivity and specificity for detection of resistance to rifampicin were 99% and 100% with NRA, 96% and 96% with MODS, 99% and 98% with Genotype^®MTBDR, and 99% and 99% with the new Genotype^®MTBDR<it>plus</it>, respectively. For isoniazid it was 94% and 100% for NRA, 92% and 96% for MODS, 71% and 100% for Genotype^®MTBDR, and 96% and 100% with the Genotype^®MTBDR<it>plus</it>, respectively. The area under the summary receiver operating characteristic (sROC) curves was in ranges of 0.98 to 1.00 for all the four tests. Molecular tests were completed in 1 – 2 days and also the phenotypic assays were much more rapid than conventional testing.</p> <p>Conclusion</p> <p>Direct testing of rifampicin and isoniazid resistance in <it>M. tuberculosis </it>was found to be highly sensitive and specific, and allows prompt detection of MDR TB.</p

Evolutionary Dynamics Analysis of Human Metapneumovirus Subtype A2: Genetic Evidence for Its Dominant Epidemic

Human metapneumovirus (hMPV) is a respiratory viral pathogen in children worldwide. hMPV is divided into four subtypes: hMPV_A1, hMPV_A2, hMPV_B1, and hMPV_B2. hMPV_A2 can be further divided into hMPV_A2a and A2b based on phylogenetic analysis. The typical prevalence pattern of hMPV involves a shift of the predominant subtype within one or two years. However, hMPV_A2, in particular hMPV_A2b, has circulated worldwide with a several years long term high epidemic. To study this distinct epidemic behavior of hMPV_A2, we analyzed 294 sequences of partial G genes of the virus from different countries. Molecular evolutionary data indicates that hMPV_A2 evolved toward heterogeneity faster than the other subtypes. Specifically, a Bayesian skyline plot analysis revealed that hMPV_A2 has undergone a generally upward fluctuation since 1997, whereas the other subtypes experienced only one upward fluctuation. Although hMPV_A2 showed a lower value of mean dN/dS than the other subtypes, it had the largest number of positive selection sites. Meanwhile, various styles of mutation were observed in the mutation hotspots of hMPV_A2b. Bayesian phylogeography analysis also revealed two fusions of diffusion routes of hMPV_A2b in India (June 2006) and Beijing, China (June 2008). Sequences of hMPV_A2b retrieved from GenBank boosted simultaneously with the two fusions respectively, indicating that fusion of genetic transmission routes from different regions improved survival of hMPV_A2. Epidemic and evolutionary dynamics of hMPV_A2b were similar to those of hMPV_A2. Overall, our findings provide important molecular insights into hMPV epidemics and viral variation, and explain the occurrence of an atypical epidemic of hMPV_A2, particularly hMPV_A2b

Etiologic Diagnosis of Lower Respiratory Tract Bacterial Infections Using Sputum Samples and Quantitative Loop-Mediated Isothermal Amplification

Etiologic diagnoses of lower respiratory tract infections (LRTI) have been relying primarily on bacterial cultures that often fail to return useful results in time. Although DNA-based assays are more sensitive than bacterial cultures in detecting pathogens, the molecular results are often inconsistent and challenged by doubts on false positives, such as those due to system- and environment-derived contaminations. Here we report a nationwide cohort study on 2986 suspected LRTI patients across P. R. China. We compared the performance of a DNA-based assay qLAMP (quantitative Loop-mediated isothermal AMPlification) with that of standard bacterial cultures in detecting a panel of eight common respiratory bacterial pathogens from sputum samples. Our qLAMP assay detects the panel of pathogens in 1047(69.28%) patients from 1533 qualified patients at the end. We found that the bacterial titer quantified based on qLAMP is a predictor of probability that the bacterium in the sample can be detected in culture assay. The relatedness of the two assays fits a logistic regression curve. We used a piecewise linear function to define breakpoints where latent pathogen abruptly change its competitive relationship with others in the panel. These breakpoints, where pathogens start to propagate abnormally, are used as cutoffs to eliminate the influence of contaminations from normal flora. With help of the cutoffs derived from statistical analysis, we are able to identify causative pathogens in 750 (48.92%) patients from qualified patients. In conclusion, qLAMP is a reliable method in quantifying bacterial titer. Despite the fact that there are always latent bacteria contaminated in sputum samples, we can identify causative pathogens based on cutoffs derived from statistical analysis of competitive relationship