Performance Enhancement of Reverse Osmosis (RO) Membrane Using Nanocomposite Materials

Many attempts were made to enhance the performance of reverse osmosis (RO) membranes in the desalination process. Using ion exchange (IX) bed before RO process and modifying the structure of RO membranes are some of these attempts. Thin film nanocomposite (TFN) membrane is the novel type of RO membranes which is the best in nanofiltration applications. TFN membranes have many new advantages due to the change of their structure in comparison with traditional membranes. In this study the performance of a TFN membrane was compared with that of standard thin film composite (TFC) spiral wound water desalination RO membrane for filtration of IX produced water. The results from the filtration process showed that the flux and water permeability of TFN are 1.55 and 1.56 times that of TFC for feed water with 2050 ppm NaCl concentration with nearly unchanged level of the membrane salt rejection, which will reduce the filtrated water cost

Homogeneous Bubble Nucleation driven by local hot spots: a Molecular Dynamics Study

We report a Molecular Dynamics study of homogenous bubble nucleation in a Lennard-Jones fluid. The rate of bubble nucleation is estimated using forward-flux sampling (FFS). We find that cavitation starts with compact bubbles rather than with ramified structures as had been suggested by Shen and Debenedetti (J. Chem. Phys. 111:3581, 1999). Our estimate of the bubble-nucleation rate is higher than predicted on the basis of Classical Nucleation Theory (CNT). Our simulations show that local temperature fluctuations correlate strongly with subsequent bubble formation - this mechanism is not taken into account in CNT

Biocontrol of Damping-Off Disease Caused by Rhizoctonia Solani in Some Medicinal Plants Using Local Strain of Streptomyces Pactum

Abstract: A number of 187 Streptomyces isolates were isolated from different Egyptian soil samples and screened for their antifungal activities (mm inhibition zone) by agar diffusion method, only 5 isolates representing 2.67% produced antifungal metabolites. Starch nitrate agar was the most suitable medium for growth and production of antifungal metabolites by different Streptomyces isolates. In addition, Streptomyces isolate S131 was the most efficient isolate in antifungal activities (mm) which was identified as a strain of Streptomyces pactum. S131 .Furthermore, the most sensitive test organism for antifungal metabolites produced by S. pactum strain S131was Aspergillus niger followed by Fusarium oxysporum, Candida albicans, Aspergillus flavus, Fusarium moniliforme, Rhizoctonia solani and Pythium sp which resulted 20, 17, 16, 15,15, 14 and 13 mm of inhibition zone around agar (6 mm) culture disks of Streptomyces pactum-S131, respectively. Application of cultural filtrate in biocontrol against damping-off caused by Rhizoctonia solani in fennel and coriander seedlings were studied, the results revealed that there were significantly differences among all soil treatments in the percentage of total survival fennel plants from damping-off disease. The maximum percentage of total survival fennel plants from damping-off disease was recorded at uninfested soil treatment followed by soil infested with R. solani + rhizolex, soil infested with R. solani + culture filtrate and soil infested with R. solani, which resulted 82.35, 69.41, 55.50 and 22.28%, respectively. In addition, there were no significantly differences between uninfested soil and soil infested with R. solani + rhizolex in the percentage of total survival coriander plants from damping-off disease, which gave 91.67 and 90.67%, respectively. But there were significantly differences between soil infested with R. solani + culture filtrate of Streptomyces pactum strain S131 and soil infested with R. solani only in the percentage of total survival coriander plants from damping-off disease, which gave 58.34 and 11.09%, respectively

Structures of Human Antibodies Bound to SARS-CoV-2 Spike Reveal Common Epitopes and Recurrent Features of Antibodies

Neutralizing antibody responses to coronaviruses mainly target the receptor-binding domain (RBD) of the trimeric spike. Here, we characterized polyclonal IgGs and Fabs from COVID-19 convalescent individuals for recognition of coronavirus spikes. Plasma IgGs differed in their focus on RBD epitopes, recognition of alpha- and beta-coronaviruses, and contributions of avidity to increased binding/neutralization of IgGs over Fabs. Using electron microscopy, we examined specificities of polyclonal plasma Fabs, revealing recognition of both S1^A and RBD epitopes on SARS-CoV-2 spike. Moreover, a 3.4Å cryo-EM structure of a neutralizing monoclonal Fab-spike complex revealed an epitope that blocks ACE2 receptor binding. Modeling based on these structures suggested different potentials for inter-spike crosslinking by IgGs on viruses and that characterized IgGs would not be affected by identified SARS-CoV-2 spike mutations. Overall, our studies structurally define a recurrent anti-SARS-CoV-2 antibody class derived from VH3-53/VH3-66 and similarity to a SARS-CoV VH3-30 antibody, providing criteria for evaluating vaccine-elicited antibodies

Symptomatic Acute Hepatitis C in Egypt: Diagnosis, Spontaneous Viral Clearance, and Delayed Treatment with 12 Weeks of Pegylated Interferon Alfa-2a

The aim of this study was to estimate the proportion of spontaneous viral clearance (SVC) after symptomatic acute hepatitis C and to evaluate the efficacy of 12 weeks of pegylated interferon alfa-2a in patients who did not clear the virus spontaneously.Patients with symptomatic acute hepatitis C were recruited from two "fever hospitals" in Cairo, Egypt. Patients still viremic three months after the onset of symptoms were considered for treatment with 12 weeks of pegylated interferon alfa-2a (180 microg/week).Between May 2002 and February 2006, 2243 adult patients with acute hepatitis were enrolled in the study. The SVC rate among 117 patients with acute hepatitis C was 33.8% (95%CI [25.9%-43.2%]) at three months and 41.5% (95%CI [33.0%-51.2%]) at six months. The sustained virological response (SVR) rate among the 17 patients who started treatment 4-6 months after onset of symptoms was 15/17 = 88.2% (95%CI [63.6%-98.5%]).Spontaneous viral clearance was high (41.5% six months after the onset of symptoms) in this population with symptomatic acute hepatitis C. Allowing time for spontaneous clearance should be considered before treatment is initiated for symptomatic acute hepatitis C

Psychosocial working conditions and the utilization of health care services

<p>Abstract</p> <p>Background</p> <p>While there is considerable theoretical and empirical evidence on how job stress affects physical and mental health, few studies have examined the association between job related stress and health care utilization. Using data from the Canadian National Population Health Survey from 2000 to 2008, this paper examines the association between stressful working conditions, as measured by the job strain model, and the utilization of health care services.</p> <p>Methods</p> <p>A zero inflated negative binomial regression is used to examine the excess health care utilization due to job strain. Separate regressions are estimated for both males and females since studies have shown gender differences in health care utilization.</p> <p>Results</p> <p>Estimates for the whole population show that high or medium job strain has a positive and statistically significant association with the number of visits to both a general practitioner (GP) and a specialist (SP). On average, the number of GP visits is up to 26% more (IRR = 1.26, 95% CI = 1.19-1.31) for individuals with high strain jobs compared to those in the low job strain category. Similarly, SP visits are up to 27% more (IRR = 1.27, 95% CI = 1.14-142) for the high strain category. Results are quantitatively similar for males and females, save for medium strain. In general, findings are robust to the inclusion of workplace social support, health status, provincial and occupational-fixed effects.</p> <p>Conclusion</p> <p>Job strain may be positively associated with the utilization of health care services. This suggests that improving psychosocial working conditions and educating workers on stress-coping mechanisms could be beneficial for the physical and mental health of workers.</p

Injection Drug Use Is a Risk Factor for HCV Infection in Urban Egypt

OBJECTIVE: To identify current risk factors for hepatitis C virus (HCV) transmission in Greater Cairo. DESIGN AND SETTING: A 1:1 matched case-control study was conducted comparing incident acute symptomatic hepatitis C patients in two "fever" hospitals of Greater Cairo with two control groups: household members of the cases and acute hepatitis A patients diagnosed at the same hospitals. Controls were matched on the same age and sex to cases and were all anti-HCV antibody negative. Iatrogenic, community and household exposures to HCV in the one to six months before symptoms onset for cases, and date of interview for controls, were exhaustively assessed. RESULTS: From 2002 to 2007, 94 definite acute symptomatic HCV cases and 188 controls were enrolled in the study. In multivariate analysis, intravenous injections (OR = 5.0; 95% CI = 1.2-20.2), medical stitches (OR = 4.2; 95% CI = 1.6-11.3), injection drug use (IDU) (OR = 7.9; 95% CI = 1.4-43.5), recent marriage (OR = 3.3; 95% CI = 1.1-9.9) and illiteracy (OR = 3.9; 95% CI = 1.8-8.5) were independently associated with an increased HCV risk. CONCLUSION: In urban Cairo, invasive health care procedures remain a source of HCV transmission and IDU is an emerging risk factor. Strict application of standard precautions during health care is a priority. Implementation of comprehensive infection prevention programs for IDU should be considered