502 research outputs found

    Transition in a numerical model of contact line dynamics and forced dewetting

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    We investigate the transition to a Landau-Levich-Derjaguin film in forced dewetting using a quadtree adaptive solution to the Navier-Stokes equations with surface tension. We use a discretization of the capillary forces near the receding contact line that yields an equilibrium for a specified contact angle θΔ\theta_\Delta called the numerical contact angle. Despite the well-known contact line singularity, dynamic simulations can proceed without any explicit additional numerical procedure. We investigate angles from 15∘15^\circ to 110∘110^\circ and capillary numbers from 0.000850.00085 to 0.20.2 where the mesh size Δ\Delta is varied in the range of 0.00350.0035 to 0.060.06 of the capillary length lcl_c. To interpret the results, we use Cox's theory which involves a microscopic distance rmr_m and a microscopic angle θe\theta_e. In the numerical case, the equivalent of θe\theta_e is the angle θΔ\theta_\Delta and we find that Cox's theory also applies. We introduce the scaling factor or gauge function ϕ\phi so that rm=Δ/ϕr_m = \Delta/\phi and estimate this gauge function by comparing our numerics to Cox's theory. The comparison provides a direct assessment of the agreement of the numerics with Cox's theory and reveals a critical feature of the numerical treatment of contact line dynamics: agreement is poor at small angles while it is better at large angles. This scaling factor is shown to depend only on θΔ\theta_\Delta and the viscosity ratio qq. In the case of small θe\theta_e, we use the prediction by Eggers [Phys. Rev. Lett., vol. 93, pp 094502, 2004] of the critical capillary number for the Landau-Levich-Derjaguin forced dewetting transition. We generalize this prediction to large θe\theta_e and arbitrary qq and express the critical capillary number as a function of θe\theta_e and rmr_m. An analogy can be drawn between rmr_m and the numerical slip length.Comment: This version of the paper includes the corrections indicated in Ref. [1

    Asemi-Empirical Study of the Adsorption of Some Organic Pollutants on Modified Iraqi Clays

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    In this work semi–empirical method (PM3) calculations are carried out by (MOPAC) computational packages have been employed to calculate the molecular orbital's energies for some organic pollutants. The long– chain quaternary ammonium cations called Iraqi Clays (Bentonite – modified) are used to remove these organic pollutants from water, by adding a small cationic surfactant so as to result in floes which are agglomerates of organobentonite to remove organic pollutants. This calculation which suggests the best surface active material, can be used to modify the adsorption efficiency of aniline , phenol, phenol deriviatives, Tri methyl glycine, ester and pecticides , on Iraqi Clay (bentonite) by comparing the theoretical results with experimental results achived in previous experimental studies between some organic pollutants and modified bentonite by (1- Hexadecyl pyridinium bromide) (HDPYBr). The theoretical calculation is made by using three surface active materials [1- (Hexadecyl pyridinium bromide) (HDPYBr), (1,12- Dipyridiniododecane dibromide) (DPYDDBr2) and Hexadecyl trimethyl ammonium bromide (HDTMA)]. Using (HDTMA) leads to the best adsorption efficiency for most pollutants involved in this study. The enthalpy of formations, dipole and energy of molecular orbitale HOMO and LUMO energies levels are calculated for all pollutants and the three surface active materials

    Yield-related salinity tolerance traits identified in a nested association mapping (NAM) population of wild barley

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    Producing sufficient food for nine billion people by 2050 will be constrained by soil salinity, especially in irrigated systems. To improve crop yield, greater understanding of the genetic control of traits contributing to salinity tolerance in the field is needed. Here, we exploit natural variation in exotic germplasm by taking a genome-wide association approach to a new nested association mapping population of barley called HEB-25. The large population (1,336 genotypes) allowed cross-validation of loci, which, along with two years of phenotypic data collected from plants irrigated with fresh and saline water, improved statistical power. We dissect the genetic architecture of flowering time under high salinity and we present genes putatively affecting this trait and salinity tolerance. In addition, we identify a locus on chromosome 2H where, under saline conditions, lines homozygous for the wild allele yielded 30% more than did lines homozygous for the Barke allele. Introgressing this wild allele into elite cultivars could markedly improve yield under saline conditions.Stephanie Saade, Andreas Maurer, Mohammed Shahid, Helena Oakey, Sandra M. Schmöckel, Sónia Negrão, Klaus Pillen and Mark Teste

    Using Phragmites australis(Iraqi plant) to remove the Lead (II) Ions form Aqueous solution.

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    Lead remediation was achieved using simple cost, effective and eco-friendly way from industrial wastewater. Phragmitesaustralis (P.a) (Iraqi plant), was used as anovel biomaterial to remove lead ions from synthesized waste water. Different parameters which affected on adsorption processes were investigated like adsorbent dose, pH, contact time, and adsorbent particle size, to reach the optimized conditions (maximum adsorption). The adsorption of Pb (?) on (P.a) involved fast and slow process as a mechanism steps according to obey two theoretical adsorption isotherms; Langmuir and Freundlich. The thermos dynamic adsorption parameters were evaluated also. The (?H) obtained positive value that meanes adsorption of lead ions was an endothermic processwhile (?G)values were negative which means that adsorption of lead ions was a spontaneous process and the decrease in (?G) with temperature increasing revealed that lead ions adsorption on (P.a) became favorable with temperature increasin

    Different techniques of surgical left atrial appendage closure and their efficacy. a systematic review

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    Background: Atrial fibrillation has been identified as an independent risk factor for thromboembolic events. Since 1948 different surgical techniques have described the feasibility and the rationale of left atrial surgical appendage closure. The aim of this systematic review is to evaluate the reported patency rates of different surgical techniques. Methods: This systematic review was conducted according to preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines. Two independent investigators searched the PubMed, Scopus, Web of Science, Cochrane Central Register of Controlled Trials, and OVID & REG; (Wolters Kluwer, Alphen aan den Rijn, Netherlands) to identify relevant studies. Consecutively, a PICO (Population, Intervention, Comparison and Outcomes) strategy assessment of literature was performed to search eventual other relevant studies that may have been ignored. Results: A total of 42 studies were included in our analysis. The total number of patients who underwent surgical left atrial appendage closure was 5671, and in 61.2% an imaging follow up was performed, mostly with transesophageal echocardiographic evaluation. Success rate for the different techniques was: Clip deployment 98%; Lariat procedure 88%; Surgical amputation 91%; Endocardial suture 74.3%, Epicardial suture 65%; Left atrial appendage closure (LAAC) ligation 60.9%; Stapler technique with excision of left atrial appendage (LAA) 100%; Stapler without excision 70%. Conclusions: To date, data on surgical left atrial appendage closure are poor and not standardized, even if reported rates are acceptable and comparable to transcatheter procedures. If validated on large-scale non-retrospective and multicentric studies, these promising developments may offer a valuable alternative for patients with atrial fibrillation (AF) and ineligible for oral anticoagulation therapy

    The effect of combined inositol supplementation on maternal metabolic profile in pregnancies complicated by metabolic syndrome and obesity

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    Myoinositol and D-chiroinositol improve insulin resistance in women with obesity and gestational diabetes and in postmenopausal women with metabolic syndrome. We previously reported that offspring born to hypertensive dams lacking endothelial nitric oxide synthase and fed a high-fat diet develop metabolic-like syndrome phenotype

    Referral Physicians’ Knowledge of Radiation Dose: A Cross-sectional Study

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    AIM: The purpose of the study was to evaluate the knowledge of referring physicians of general practitioners, residents, and medical specialists in Jordan and the Middle East on radiation dose and its impact on vulnerable patients. MATERIALS AND METHODS: The Institutional Review Board approved this study before data collection. A cross-sectional study employed questionnaire that was distributed to respondents (n = 293) of general practitioners, residents, specialists, and therapists. The questionnaire consisted of 29 questions. Nine questions concerned with demographics and the remaining 20 questions were divided into five sections: Radiation dose, ionizing radiation, pediatric radiation, pregnant women radiation, and radiation risks. The mean score was computed out of 20. Chi-squared test of independence was utilized to analyze each question. To compare the responses between the demographic variables groups, Kruskal–Wallis and Mann–Whitney tests were used. RESULTS: Out of the 293 respondents, 128 (43.7%) were aware of radiation. The average score of the questionnaire was 9.5 out of 20 (47.5%). Within each section, the level of knowledge varied. Physicians had the highest level of knowledge in radiation risk (85.7%) followed by ionizing radiation (62.1%). The questionnaire revealed lower levels of knowledge in the areas of pediatric radiation, pregnant women radiation, and radiation dose. The percentages of respondents, (with fair to good level of knowledge), were 47.1%, 34.5%, and 24.6%, respectively. CONCLUSION: The results of this study were consistent with previous studies that demonstrated a poor level of general knowledge in referring physicians regarding radiation dose, ionizing radiation, pediatric radiation, pregnant women radiation, and radiation risks

    Randomized Trials of Retosiban Versus Placebo or Atosiban in Spontaneous Preterm Labor.

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    OBJECTIVE:  The aim of this study is to assess the efficacy and safety of retosiban in spontaneous preterm labor (sPTL). STUDY DESIGN:  Two multicenter, randomized, and double-blind trials compared retosiban with placebo and retosiban with atosiban in women with a singleton pregnancy and intact membranes in sPTL at 24 to 336/7 weeks' gestation. Coprimary endpoints in the placebo-controlled trial were time to delivery (TTD) or treatment failure (whichever occurred first) and neonatal composite morbidity and mortality. The primary endpoint of the atosiban comparator trial was TTD. RESULTS:  The trials were terminated early because of slow recruitment. The placebo-controlled trial enrolled 23 participants (February 2016-July 2017; 2.6% of target);the atosiban-comparator trial enrolled 97 (March 2015-August 2017; 29% of target). Baseline participant characteristics were similar between treatments. In the placebo-controlled trial, mean gestational ages at randomization were 30.8 (retosiban, n = 10) and 30.5 weeks (placebo, n = 13), and mean times to delivery/treatment failure were 18.9 days (retosiban) and 11.1 days (placebo). Two and four neonates in the retosiban and placebo groups, respectively, had ≥1 component of the neonatal composite endpoint. In the atosiban-comparator trial, mean gestational age at randomization was 31.5 weeks (for both retosiban, n = 47, and atosiban, n = 50), and adjusted mean TTDs were 32.51 days (retosiban) and 33.71 days (atosiban; p > 0.05). Adverse events were no more common with retosiban than placebo or atosiban. CONCLUSION:  Despite considerable efforts to conduct two adequate and well-controlled studies in patients with sPTL, both studies were unable to recruit effectively and consequently terminated prematurely. Key factors negatively affecting participation were patient and physician resistance to use of a placebo comparator, lack of investigator consensus on diagnostic criteria and acceptance of protocol procedures, and ethics committee decisions. Meaningful cooperation between pharmaceutical companies, regulatory authorities, and the obstetric community is essential for future development of drugs to treat sPTL

    The NAVIGATE Program for First-Episode Psychosis: Rationale, Overview, and Description of Psychosocial Components

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    Comprehensive coordinated specialty care programs for first-episode psychosis have been widely implemented in other countries but not in the United States. The National Institute of Mental Health\u27s Recovery After an Initial Schizophrenia Episode (RAISE) initiative focused on the development and evaluation of first-episode treatment programs designed for the U.S. health care system. This article describes the background, rationale, and nature of the intervention developed by the RAISE Early Treatment Program project-known as the NAVIGATE program-with a particular focus on its psychosocial components. NAVIGATE is a team-based, multicomponent treatment program designed to be implemented in routine mental health treatment settings and aimed at guiding people with a first episode of psychosis (and their families) toward psychological and functional health. The core services provided in the NAVIGATE program include the family education program (FEP), individual resiliency training (IRT), supported employment and education (SEE), and individualized medication treatment. NAVIGATE embraces a shared decision-making approach with a focus on strengths and resiliency and on collaboration with clients and family members in treatment planning and reviews. The NAVIGATE program has the potential to fill an important gap in the U.S. health care system by providing a comprehensive intervention specially designed to meet the unique treatment needs of persons recovering from a first episode of psychosis. A cluster-randomized controlled trial comparing NAVIGATE with usual community care has recently been completed
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