275 research outputs found

    Microcanonical Simulation of Complex Actions: The Wess Zumino Witten Case

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    We present the main results of our microcanonical simulation of the Wess Zumino Witten action functional. This action, being highly non-trivial and capable of exhibiting many different phase transitions, is chosen to be representative of general complex actions. We verify the applicability of microcanonical simulation by successfully obtaining two of the many critical points of the Wess Zumino Witten action. The microcanonical algorithm has the additional advantage of exhibiting critical behaviour for a small 8×88\times 8 lattice. We also briefly discuss the subtleties that, in general, arise in simulating a complex action. Our algorithm for complex actions can be extended to the study of D-branes in the Wess Zumino Witten action.Comment: 5 figure

    Mechanical properties study of pseudo-stem banana fiber reinforced epoxy composite

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    The source of banana fiber is the waste banana trunks or stems which are abundant in many places in the world. Therefore, composites of high–strength pseudo-stem banana woven fabric reinforcement polymer can be used in a broad range of applications. The objective of this paper is to study the tensile, flexural, and impact properties of pseudostem banana fiber reinforced epoxy composites

    High frequency current sensing using optical fiber micro-wire

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    Fiber-optic current sensors exploiting the Faraday effect have attracted a great deal of interest due to their wide dynamic range, robustness and remote sensing capability. Recently a new approach to current sensing using optical fiber micro-wire (OFM) with 5µm diameter in the configuration of a micro-coil (MC) has been proposed and successfully demonstrated [1]. It featured high compactness, robustness, configurability and excellent confinement of light and was able to demonstrate its ability to sense currents with a 1µs rise time. In this paper we present a major improvement in the current sensing bandwidth, demonstrating a capability to detect a fast current pulse with pulse width (full width at half maximum: FWHM) of 6.7ns

    Rates and Determinants of Mother\u27s Own Milk Feeding in Infants Born Very Preterm

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    Objectives: To examine rates and determinants of mother\u27s own milk (MOM) feeding at hospital discharge in a cohort of infants born very preterm within the Canadian Neonatal Network (CNN). Study design: This was a population-based cohort study of infants born at (NICUs) participating in the CNN between January 1, 2015, and December 31, 2018. We examined the rates and determinants of MOM use at discharge home among the participating NICUs. We used multivariable logistic regression analysis to identify independent determinants of MOM feeding. Results: Among the 6404 infants born very preterm and discharged home during the study period, 4457 (70%) received MOM or MOM supplemented with formula. Rates of MOM feeding at discharge varied from 49% to 87% across NICUs. Determinants associated with MOM feeding at discharge were gestational age 29-32 weeks compared with (aOR 1.56, 95% CI 1.25-1.93), primipara mothers (aOR 2.12, 95% CI 1.86-2.42), maternal diabetes (aOR 0.79, 95% CI 0.66-0.93), and maternal smoking (aOR 0.27, 95% CI 0.19-0.38). Receipt of MOM by day 3 of age was the major predictor of breast milk feeding at discharge (aOR 3.61, 95% CI 3.17-4.12). Conclusions: Approximately two-thirds of infants born very preterm received MOM at hospital discharge, and rates varied across NICUs. Supporting mothers to provide breast milk in the first 3 days after birth may be associated with improved MOM feeding rates at discharge

    Synchronous fluorescence spectrofluorimetric method for the simultaneous determination of metoprolol and felodipine in combined pharmaceutical preparation

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    A rapid, simple and sensitive synchronous specrtofluorimetric method has been developed for the simultaneous analysis of binary mixture of metoprolol (MTP) and felodipine (FDP). The method is based upon measurement of the synchronous fluorescence intensity of the two drugs at Δλ of 70 nm in aqueous solution. The different experimental parameters affecting the synchronous fluorescence intensities of the two drugs were carefully studied and optimized. The fluorescence intensity-concentration plots were rectilinear over the ranges of 0.5-10 μg/mL and 0.2-2 μg/mL for MTP and FDP, respectively. The limits of detection were 0.11 and 0.02 μg/mL and quantification limits were 0.32 and 0.06 μg/mL for MTP and FDP, respectively. The proposed method was successfully applied for the determination of the two compounds in their commercial tablets and the results obtained were favorably compared to those obtained with a comparison method

    First report of mobile colistin resistance gene mcr-1 in avian pathogenic Escherichia coli isolated from turkeys in the Gaza Strip, Palestine

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    Background and Aim: Colistin is used to treat avian pathogenic Escherichia coli (APEC), a microorganism that affects turkey meat production in the Gaza Strip and worldwide. However, the recent emergence of plasmid-borne mobile colistin resistance (mcr) genes in pathogenic E. coli strains is a serious antimicrobial resistance (AMR) challenge for both human and animal health. In December 2018, colistin was banned as a veterinary antimicrobial in the Gaza Strip. This study aimed to detect and track the prevalence of colistin-resistant APEC isolated from turkey flocks in the Gaza Strip. Materials and Methods: This study investigated 239 APEC isolates from turkey flocks in the Gaza Strip between October 2018 and December 2021 (at 6-month intervals). The colistin-resistant APEC strains were detected using the broth microdilution method. The mcr-1 gene was identified using a polymerase chain reaction. Results: The overall colistin resistance among the isolated APECs was 32.2% during the study period. The average resistance in the first interval was 37.5%, which significantly decreased to 9.3% in the last interval. Among the 77 phenotypically resistant isolates, 32.4% were positive for mcr-1. The average abundance of mcr-1 in the first interval was 66.6%, which decreased to 25% in the last interval. Conclusion: To the best of our knowledge, this is the first study reporting the presence of the mcr-1 gene among the APEC isolates from turkeys in the Gaza Strip. Banned veterinary use of colistin significantly decreased the percentage of resistant APEC isolates from turkeys in Gaza Strip. Further studies are needed to investigate other colistin resistance genes and track the emergence of AMR

    Istodobno spektrofotometrijsko određivanje losartan kalija, amlodipin besilata i hidroklorotiazida u farmaceutskim pripravcima kemometrijskom metodom

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    In the present work, four different spectrophotometric methods for simultaneous estimation of losartan potassium, amlodipine besilate and hydrochlorothiazide in raw materials and in formulations are described. Overlapped data was quantitatively resolved by using chemometric methods, classical least squares (CLS), multiple linear regression (MLR), principal component regression (PCR) and partial least squares (PLS). Calibrations were constructed using the absorption data matrix corresponding to the concentration data matrix, with measurements in the range of 230.5350.4 nm (∆λ = 0.1 nm) in their zero order spectra. The linearity range was found to be 840, 15 and 315 μg ml1 for losartan potassium, amlodipine besilate and hydrochlorothiazide, respectively. The validity of the proposed methods was successfully assessed for analyses of drugs in the various prepared physical mixtures and in tablet formulations.U radu su opisane četiri spektrofotometrijske metode za istodobno određivanje losartan kalija, amlodipin besilata i hidroklorotiazida u sirovinama i farmaceutskim pripravcima. Podaci koji su se preklapali kvantitativno su razlučeni kemometrijskim metodama, klasičnom metodom najmanjih kvadrata (CLS), multiplom linearnom regresijom (MLR), regresijom glavnih komponenata (PCR) te metodom parcijalnih najmanjih kvadrata (PLS). Kalibracije su provedene koristeći podatke o ovisnosti apsorpcije o koncentracijama, mjereći spektre nultog reda u rasponu 230,5350,4 nm (∆λ = 0,1 nm). Linearnost za losartan kalij bila je 840, za amlodipin besilat 15, a za hidroklorotiazid 315 μg ml1. Valjanost predloženih metoda uspješno je potvrđena analizom navedenih lijekova u različitim pripremljenim smjesama i tabletama

    Spectrofluorimetric determination of sertraline in dosage forms and human plasma through derivatization with 9-fluorenylmethyl chloroformate

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    <p>Abstract</p> <p>Background</p> <p>Sertraline is primarily used to treat major depression in adult outpatients as well as obsessive-compulsive, panic and social anxiety disorders in both adults and children. A survey of the literature reveals that most of the reported methods are either insufficiently sensitive or tedious and require highly sophisticated and dedicated instrumentation. The proposed method is considered to be specific for determination of SER in presence of its metabolite (deaminated form).</p> <p>Results</p> <p>A sensitive, simple and specific spectrofluorimetric method was developed for the determination of sertraline (SER) in pharmaceutical formulations and biological fluids. The method is based on its reaction with 9-fluorenylmethyl chloroformate (FMOC-Cl) in borate buffer of pH 8.0 to yield a highly fluorescent derivative peaking at 315 nm after excitation at 265 nm. The different experimental parameters affecting the development and stability of the reaction product were carefully studied and optimized. The fluorescence concentration plot was rectilinear over the range of 0.05-1.0 μg mL<sup>-1 </sup>with a lower detection limit of 5.34 × 10<sup>-3 </sup>μg mL<sup>-1 </sup>and limit of quantitation of 0.016 μg mL<sup>-1</sup>.</p> <p>Conclusions</p> <p>The proposed method was successfully applied to the analysis of commercial tablets and the results obtained were in good agreement with those obtained using the reference method. Furthermore, the method was applied for the determination of SER in spiked and real human plasma. The mean % recovery (n = 3) was 94.33 ± 1.53 and 92.00 ± 2.65, respectively. A proposal of the reaction pathway was postulated.</p

    Utility of certain nucleophilic aromatic substitution reactions for the assay of pregabalin in capsules

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    <p>Abstract</p> <p>Background</p> <p>Pregabalin (PG) is an anticonvulsant, analgesic and anxiolytic drug. A survey of the literature reveals that all the reported spectrophotometric methods are either don't offer high sensitivity, need tedious extraction procedures, recommend the measurement of absorbance in the near UV region where interference most probably occurs and/or use non specific reagent that don't offer suitable linearity range.</p> <p>Results</p> <p>Two new sensitive and simple spectrophotometric methods were developed for determination of pregabalin (PG) in capsules. Method (I) is based on the reaction of PG with 1,2-naphthoquinone-4-sulphonate sodium (NQS), yielding an orange colored product that was measured at 473 nm. Method (II) is based on the reaction of the drug with 2,4-dinitrofluorobenzene (DNFB) producing a yellow product measured at 373 nm. The different experimental parameters affecting the development and stability of the reaction product in methods (I) and (II) were carefully studied and optimized. The absorbance-concentration plots were rectilinear over the concentration ranges of 2-25 and 0.5-8 μg mL<sup>-1 </sup>for methods (I) and (II) respectively. The lower detection limits (LOD) were 0.15 and 0.13 μg mL<sup>-1 </sup>and the lower quantitation limits (LOQ) were 0.46 and 0.4 μg mL<sup>-1 </sup>for methods (I) and (II) respectively.</p> <p>Conclusion</p> <p>The developed methods were successfully applied to the analysis of the drug in its commercial capsules. The mean percentage recoveries of PG in its capsule were 99.11 ± 0.98 and 100.11 ± 1.2 (n = 3). Statistical analysis of the results revealed good agreement with those given by the comparison method. Proposals of the reaction pathways were postulated.</p

    Higher ethical objective (Maqasid al-Shari'ah) augmented framework for Islamic banks : assessing the ethical performance and exploring its determinants.

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    This study utilises higher objectives postulated in Islamic moral economy or the maqasid al-Shari’ah theoretical framework’s novel approach in evaluating the ethical, social, environmental and financial performance of Islamic banks. Maqasid al-Shari’ah is interpreted as achieving social good as a consequence in addition to well-being and, hence, it goes beyond traditional (voluntary) social responsibility. This study also explores the major determinants that affect maqasid performance as expressed through disclosure analysis. By expanding the traditional maqasid al-Shari’ah,, we develop a comprehensive evaluation framework in the form of a maqasid index, which is subjected to a rigorous disclosure analysis. Furthermore, in identifying the main determinants of the maqasid disclosure performance, panel data analysis is used by including several key variables alongside political and socio-economic environment, ownership structures, and corporate and Shari’ah governance-related factors. The sample includes 33 full-fledged Islamic banks from 12 countries for the period of 2008–2016. The findings show that although during the nine-year period the disclosure of maqasid performance of the sampled Islamic banks has improved, this is still short of ‘best practices’. Through panel data analysis, this study finds that the Muslim population indicator, CEO duality, Shari’ah governance, and leverage variables positively impact the disclosure of maqasid performance. However, the effect of GDP, financial development and human development index of the country, its political and civil rights, institutional ownership, and a higher share of independent directors have an overall negative impact on the maqasid performance. The findings reported in this study identify complex and multi-faceted relations between external market realities, corporate and Shari’ah governance mechanisms, and maqasid performance
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