35 research outputs found

    Development of a new medium containing date syrup for production of bleomycin by Streptomyces mobaraensis ATCC 15003 using response surface methodology

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    A combined statistical approach of orthogonal design and polynomial regression were applied to optimize the composition and concentration of a liquid fermentation medium for the production of bleomycin (BLM) by Streptomyces mobaraensis. Optimal conditions for maximal productivity were determined based on eight parameters at three different levels. The sources of carbon and nitrogen concentration and their interactions with other precursors were found to be statistically significant factors. When date syrup was used as an additional carbon source, higher BLM amount was obtained in comparison to glucose. It was found that the optimum nitrogen source was achieved with the use of soyabean meal. The combined orthogonal design and response surface methodology predicted optimal conditions for production of BLM to be 138 mg dl-1. A confirmatory experiment of the optimal medium composition produced 142 mg dl-1 in the fifth day fermentation at 30°C. The complex medium containing 40 gml-1 date syrup as additional carbon source enhanced the production of BLM by 73%. The combined statistical approach enabled rapid identification and integration of key medium parameters for optimizing secondary metabolite production and could be very useful in pharma-ceutical screening programs.Keywords: Bleomycin, Streptomyces mobaraensis, orthogonal design, medium optimization, date syrupAfrican Journal of Biotechnology Vol. 9(33), pp. 5450-5459, 16 August, 201

    International longitudinal registry of patients with atrial fibrillation and treated with rivaroxaban: RIVaroxaban Evaluation in Real life setting (RIVER)

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    Background Real-world data on non-vitamin K oral anticoagulants (NOACs) are essential in determining whether evidence from randomised controlled clinical trials translate into meaningful clinical benefits for patients in everyday practice. RIVER (RIVaroxaban Evaluation in Real life setting) is an ongoing international, prospective registry of patients with newly diagnosed non-valvular atrial fibrillation (NVAF) and at least one investigator-determined risk factor for stroke who received rivaroxaban as an initial treatment for the prevention of thromboembolic stroke. The aim of this paper is to describe the design of the RIVER registry and baseline characteristics of patients with newly diagnosed NVAF who received rivaroxaban as an initial treatment. Methods and results Between January 2014 and June 2017, RIVER investigators recruited 5072 patients at 309 centres in 17 countries. The aim was to enroll consecutive patients at sites where rivaroxaban was already routinely prescribed for stroke prevention. Each patient is being followed up prospectively for a minimum of 2-years. The registry will capture data on the rate and nature of all thromboembolic events (stroke / systemic embolism), bleeding complications, all-cause mortality and other major cardiovascular events as they occur. Data quality is assured through a combination of remote electronic monitoring and onsite monitoring (including source data verification in 10% of cases). Patients were mostly enrolled by cardiologists (n = 3776, 74.6%), by internal medicine specialists 14.2% (n = 718) and by primary care/general practice physicians 8.2% (n = 417). The mean (SD) age of the population was 69.5 (11.0) years, 44.3% were women. Mean (SD) CHADS2 score was 1.9 (1.2) and CHA2DS2-VASc scores was 3.2 (1.6). Almost all patients (98.5%) were prescribed with once daily dose of rivaroxaban, most commonly 20 mg (76.5%) and 15 mg (20.0%) as their initial treatment; 17.9% of patients received concomitant antiplatelet therapy. Most patients enrolled in RIVER met the recommended threshold for AC therapy (86.6% for 2012 ESC Guidelines, and 79.8% of patients according to 2016 ESC Guidelines). Conclusions The RIVER prospective registry will expand our knowledge of how rivaroxaban is prescribed in everyday practice and whether evidence from clinical trials can be translated to the broader cross-section of patients in the real world

    High performance nature of biodegradable polymeric nanocomposites for oil-well drilling fluids

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    © 2015 The Authors Multi-walled carbon nanotube (MWCNT) and graphene nanoplatelet reinforced thermoplastic poly(lactic acid) (PLA) biodegradable nanocomposites were designed and prepared using solution casting techniques. The prepared biodegradable polymers are expected to provide an environmentally friendly alternative to petroleum-based polymers. Both nanocomposite systems exhibited better thermal stability and improved mechanical performance over the unreinforced polymer exhibiting excellent strength and degradability. The addition of graphene nanofiller in varied amounts was aimed to enhance the thermal and mechanical properties of the nanocomposites even further and incorporate the outstanding characteristics of graphene nanoplatelets into the nanocomposites. The polymeric nanocomposites showed also superior advantages for oil drilling relevances, automotive lubricating purposes, membrane technology and food packaging. Scanning electron microscopy images indicated a homogeneous dispersion of the nanofiller within the polymeric matrix at low filler loadings and a cluster formation at higher loadings that could be responsible for the polymeric matrix movement restrictions. The enthalpy of mixing (the polymer and the nanofiller) measured could explain the cause of the repulsive interactions between the nanoparticles and the polymeric chains, which created an additional excluded volume that the polymeric segments were restricted to occupy, thus forcing the conformational characteristics of the polymeric chains to deviate away from those of the bulk chains. The prepared polymeric nano composites (poly lactic acid carbon nano tube and poly lactic acid graphene nanoplatelets) were utilized in the formulation of oil-base mud as a viscosifier. The rheological, filtration properties and electrical stability of the oil based mud formulation with the new polymeric nanocomposite were studied and the result compared to the oil-based mud formulation with commercial viscosifier

    MTHFR Genetic Polymorphism As a Risk Factor in Egyptian Mothers with Down Syndrome Children

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    Recent reports linking Down syndrome (DS) to maternal polymorphisms at the methylenetetrahydrofolate reductase (MTHFR) gene locus have generated great interest among investigators in the field. The present study aimed at evaluation of MTHFR 677C/T and 1298A/C polymorphisms in the MTHFR gene as maternal risk factors for DS. Forty two mothers of proven DS outcomes and forty eight control mothers with normal offspring were included. Complete medical and nutritional histories for all mothers were taken with special emphasis on folate intake. Folic acid intake from food or vitamin supplements was significantly low (below the Recommended Daily Allowance) in the group of case mothers compared to control mothers. Frequencies of MTHFR 677T and MTHFR 1298C alleles were significantly higher among case mothers (32.1% and 57.1%, respectively) compared to control mothers (18.7% and 32.3%, respectively). Heterozygous and homozygous genotype frequencies of MTHFR at position 677 (CT and TT) were higher among case mothers than controls (40.5% versus 25% and 11.9% versus 6.2%, respectively) with an odds ratio of 2.34 (95% confidence interval [CI] 0.93–5.89) and 2.75 (95% CI 0.95–12.77), respectively. Interestingly, the homozygous genotype frequency (CC) at position 1298 was significantly higher in case mothers than in controls (33.3% versus 2.1% respectively) with an odds ratio of 31.5 (95% CI 3.51 to 282.33) indicating that this polymorphism may have more genetic impact than 677 polymorphism. Heterozygous genotype (AC) did not show significant difference between the two groups. We here report on the first pilot study of the possible genetic association between DS and MTHFR 1298A/C genotypes among Egyptians. Further extended studies are recommended to confirm the present work

    MTHFR genetic polymorphism as a risk factor in Egyptian mothers with Down syndrome children. Dis

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    Abstract. Recent reports linking Down syndrome (DS) to maternal polymorphisms at the methylenetetrahydrofolate reductase (MTHFR) gene locus have generated great interest among investigators in the field. The present study aimed at evaluation of MTHFR 677C/T and 1298A/C polymorphisms in the MTHFR gene as maternal risk factors for DS. Forty two mothers of proven DS outcomes and forty eight control mothers with normal offspring were included. Complete medical and nutritional histories for all mothers were taken with special emphasis on folate intake. Folic acid intake from food or vitamin supplements was significantly low (below the Recommended Daily Allowance) in the group of case mothers compared to control mothers. Frequencies of MTHFR 677T and MTHFR 1298C alleles were significantly higher among case mothers (32.1% and 57.1%, respectively) compared to control mothers (18.7% and 32.3%, respectively). Heterozygous and homozygous genotype frequencies of MTHFR at position 677 (CT and TT) were higher among case mothers than controls (40.5% versus 25% and 11.9% versus 6.2%, respectively) with an odds ratio of 2.34 (95% confidence interval [CI] 0.93-5.89) and 2.75 (95% CI 0.95-12.77), respectively. Interestingly, the homozygous genotype frequency (CC) at position 1298 was significantly higher in case mothers than in controls (33.3% versus 2.1% respectively) with an odds ratio of 31.5 (95% CI 3.51 to 282.33) indicating that this polymorphism may have more genetic impact than 677 polymorphism. Heterozygous genotype (AC) did not show significant difference between the two groups. We here report on the first pilot study of the possible genetic association between DS and MTHFR 1298A/C genotypes among Egyptians. Further extended studies are recommended to confirm the present work

    Insight into the Influence of the Integrated Chitosan on the Adsorption Properties of Chitosan/Al-MCM-41 Composite for As (V) Metal Ions: Characterization and Advanced Equilibrium Studies

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    Ecofriendly chitosan/Al-MCM-48 (CH/Al-MCM) was synthesized from natural microcline and assessed as a potential adsorbent of As (V) ions with enhanced capacity. The As (V) adsorption properties of CH/Al-MCM were assessed in comparison with Al-MCM-41 as a single phase. The studied CH/Al-MCM exhibits 178.6 mg/g as As (V) adsorption capacity which is higher than Al-MCM-41 (124 mg/g). The adsorption properties were illustrated based on the pseudo-first-order kinetic, Langmuir isotherm, and monolayer model with one energy site. Based on the recognized steric parameters, CH/Al-MCM displays significant enhancement in the active sites density (Nm = 88.8 mg/g (20°C)) as compared to Al-MCM (Nm = 61.5 mg/g). This signifies the role of the chitosan integration process in enhancing the adsorption capacity by increasing the availability of the present active sites. The number of adsorbed arsenic ions (2.01 to 2.66) suggests the uptake of 2 or 3 ions per free site by a multi-ionic and physical mechanism considering the adsorption energy (−16.3 to −16.9 kJ/mol). The thermodynamic functions of entropy, internal energy, and free enthalpy reflect the spontaneous and exothermic properties of the studied As (V) adsorption system by CH/Al-MCM. Moreover, the composite displays significant As (V) adsorption capacity in the existence of other dissolved ions
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