201 research outputs found

    Theoretical analysis of triple-pass erbium-doped fiber amplifier

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    Many configurations of EDFA producing triple pass EDFAs have been used, however, only two configurations are commonly used in the optical fiber communication system due to their high performance. Those two configurations are configured in a double stage EDFA. The first configuration is (configuration A) consists of a single-pass EDFA as the first stage and a double-pass EDFA as the second stage. The second configuration is (Configuration B) which consists of a double-pass EDFA as the first stage and a single-pass EDFA as the second stage. The Literature shows the use of triple pass EDFA is either with configuration A or configuration B and literature also shows there is no theoretical analysis and comparison between the performance of two Triple-pass EDFA configurations A and B. This paper focus on the performance analysis of both configurations A and B. The importantance of this research is the theoretical analyses that analyze the performance of those two configurations and illustrate a comparison between them. This comparison is important to show which of the two configurations is more reliable in amplifying optical signal for the fiber optic communication systems

    High Performance Liquid Chromatographic Assay for the Simultaneous Determination of Posaconazole and Vincristine in Rat Plasma

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    Purpose. Developing a validated HPLC-DAD method for simultaneous determination of posaconazole (PSZ) and vincristine (VCR) in rat plasma. Methods. PSZ, VCR, and itraconazole (ITZ) were extracted from 200 μL plasma using diethyl ether in the presence of 0.1 M sodium hydroxide solution. The organic layer was evaporated in vacuo and dried residue was reconstituted and injected through HC-C18 (4.6 × 250 mm, 5 μm) column. In the mobile phase, acetonitrile and 0.015 M potassium dihydrogen orthophosphate (30 : 70 to 80 : 20, linear gradient over 7 minutes) pumped at 1.5 mL/min. VCR and PSZ were measured at 220 and 262 nm, respectively. Two Sprague Dawley rats were orally dosed PSZ followed by iv dosing of VCR and serial blood sampling was performed. Results. VCR, PSZ, and ITZ were successfully separated within 11 min. Calibration curves were linear over the range of 50–5000 ng/mL for both drugs. The CV% and % error of the mean were ≤18% and limit of quantitation was 50 ng/mL for both drugs. Rat plasma concentrations of PSZ and VCR were simultaneously measured up to 72 h and their calculated pharmacokinetics parameters were comparable to the literature. Conclusion. The assay was validated as per ICH guidelines and is appropriate for pharmacokinetics drug-drug interaction studies

    Shear Performance of GFRP Reinforced Concrete Beams with Seawater and Chopped Fiber

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    This paper reports an experimental study on the behavior and shear strength of concrete beams reinforced with longitudinal GFRP bars mixed with sea water. In order to evaluate how much concrete contributes to shear resistance, seven beams were tested in bending. Similar in size and concrete strength, the beams were longitudinally reinforced with glass fiber-reinforced polymer bars; however, they did not even have shear reinforcement. The beams, which measured 3,100 mm in length, 400 mm in depth, and 200 mm in width, were conducted and tested up to failure. The test variables were longitudinal reinforcement ratios (1.0, 1.4, and 2.0%), chopped fiber content (0, 0.5, 2, and 3 kg/m3), and mixing water type (freshwater and seawater). The test findings showed that increasing the reinforcement ratio increased the neutral-axis depth and allowed the formation of more closely spaced fractures while decreasing the loss of flexural stiffness after cracking. By increasing the area of concrete in compression, this in turn enhances the contribution of aggregate interlock as well as the contribution of uncracked concrete. Furthermore, increasing the reinforcement ratio improves the dowel action, which reduces the tensile stresses that are created in the concrete around it. Doi: 10.28991/CEJ-2023-09-04-05 Full Text: PD

    Genetic Diversity and Population Structure of F3:6 Nebraska Winter Wheat Genotypes Using Genotyping-By-Sequencing

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    The availability of information on the genetic diversity and population structure in wheat (Triticum aestivum L.) breeding lines will help wheat breeders to better use their genetic resources and manage genetic variation in their breeding program. The recent advances in sequencing technology provide the opportunity to identify tens or hundreds of thousands of single nucleotide polymorphism (SNPs) in large genome species (e.g., wheat). These SNPs can be utilized for understanding genetic diversity and performing genome wide association studies (GWAS) for complex traits. In this study, the genetic diversity and population structure were investigated in a set of 230 genotypes (F3:6) derived from various crosses as a prerequisite for GWAS and genomic selection. Genotyping-by-sequencing provided 25,566 high-quality SNPs. The polymorphism information content (PIC) across chromosomes ranged from 0.09 to 0.37 with an average of 0.23. The distribution of SNPs markers on the 21 chromosomes ranged from 319 on chromosome 3D to 2,370 on chromosome 3B. The analysis of population structure revealed three subpopulations (G1, G2, and G3). Analysis of molecular variance identified 8% variance among and 92% within subpopulations. Of the three subpopulations, G2 had the highest level of genetic diversity based on three genetic diversity indices: Shannon’s information index (I) = 0.494, diversity index (h) = 0.328 and unbiased diversity index (uh) = 0.331, while G3 had lowest level of genetic diversity (I = 0.348, h = 0.226 and uh = 0.236). This high genetic diversity identified among the subpopulations can be used to develop new wheat cultivars

    A guide to best practice in faculty development for health professions schools: a qualitative analysis

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    BACKGROUND: This is a practice guide for the evaluation tool specifically created to objectively evaluate longitudinal faculty development programs (FDP) using the “5×2 -D backward planning faculty development model”. It was necessary to create this tool as existing evaluation methods are designed to evaluate linear faculty development models with a specific endpoint. This backward planning approach is a cyclical model without an endpoint, consisting of 5 dynamic steps that are flexible and interchangeable, therefore can be a base for an evaluation tool that is objective and takes into account all the domains of the FDP in contrast to the existing, traditional, linear evaluation tools which focus on individual aspects of the program. The developed tool will target evaluation of longitudinal faculty development programs regardless of how they were planned. METHODOLOGY: Deductive qualitative grounded theory approach was used. Evaluation questions were generated and tailored based on the 5 × 2-D model followed by 2 Delphi rounds to finalize them. Based on the finalized evaluation questions from the results of the Delphi rounds, two online focus group discussions (FGDs) were conducted to deduce the indicators, data sources and data collection method. RESULTS: Based on the suggested additions, the authors added 1 new question to domains B, with a total of 42 modifications, such as wording changes or discarding or merging questions. Some domains received no comments, therefore, were not included in round 2. For each evaluation question, authors generated indicators, data sources and data collection methods during the FGD. CONCLUSION: The methodology used to develop this tool takes into account expert opinions. Comprehensiveness of this tool makes it an ideal evaluation tool during self-evaluation or external quality assurance for longitudinal FDP. After its validation and testing, this practice guide can be used worldwide, along with the provided indicators which can be quantified and used to suit the local context. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12909-022-03208-x

    EFFECT OF MULTIMEDIA ACTIVITIES IN BLENDED LEARNING ON LISTENING SKILLS AND SATISFACTION IN A COLLEGE ENGLISH LANGUAGE COURSE

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    This study aimed to investigate the effect of proposed multimedia activities in blended learning on students’ listening skills and satisfaction in a college English language course at the Royal University for Woman (RUW) in Bahrain. The study attempted to assess the effects of the proposed strategy on the students’ listening skills and satisfaction with the multimedia listening activities in the OPL (Orientation Program Lower). Results indicated that experimental group students scored higher level in their listening post-test than those in the control group. Experimental group students were satisfied with the courses designed.KEYWORDS: multimedia activities, interactive multimedia, listening comprehension, blended learning

    Avascular bone necrosis of the femoral head after renal transplantation: Is it avoidable?

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    Background: Avascular osteonecrosis (AVN) is a seriousosseous complication after renal transplantation (RT). Itsprevalence clearly decreased from 20% to 4% possiblydue to the use of calcinurin inhibitors (CNI), reduction ofsteroid doses and use of steroid free regimens. The aimof our study was to evaluate the frequency of AVNamong our kidney transplant recipients and to determinethe risk factors for its occurrence.Patients and methods: Among 1785 kidney transplantrecipients who received renal allografts between March1976 and December 2005, 40 patients (2.24%) developedAVN with a mean age of 31.3 10.2 years. Eightykidney transplant recipients without AVN were selectedto be a matched control group. The localization of AVNwas the femoral head in all cases.Results: AVN was diagnosed at a mean of 20.4 monthsafter transplantation. The following risk factors werestatistically significant; sirolimus-based regimen,hypercholesterolemia, overweight with body mass index(BMI)>26 and those with HLA A9, HLA B35 and DRB15.Conclusions: We concluded that the proper managementof hypercholesterolemia, maintenance of ideal bodyweight as well as avoidance of sirolimus-basedimmunosuppressive regimen in genetically predisposedpatients may be an effective preventive strategy to avoidAVN

    The impact of Oligo-miocene basaltic intrusions on the petroleum system in Gulf of Suez rift basin, Egypt: new insights into tikhermal maturity and reservoir quality

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    In recent years, the petroleum industry has prioritized the exploration of new and unconventional petroleum reservoirs. As a result, this study assessed the significance of basaltic intrusions from two key aspects: their impact on the thermal maturity of pre-rift source rocks and their potentiality as reservoirs. The present study attempts to integrate surface field investigations of basaltic dykes in Wadi Nukhul and Wadi Matulla as surface analogs with petroleum system modeling of pre-rift source rocks containing subsurface basaltic intrusions in the Abu Rudeis-Sidri field. Therefore, the fracture networks were observed in Wadi Nukhul and Wadi Matulla, suggesting that both the basaltic dykes and host rocks have interconnected fractures, which is critical for a high-quality reservoir of the dykes and efficient oil expulsion. As a result, the analysis of burial history, temperature, maturity, generation, transformation ratio, and expelled oil quantity revealed a significantly high value for basaltic intrusions. Moreover, the Abu Rudeis-Sidri field had a good petroleum system with thermally mature source rocks by basaltic intrusions. Furthermore, the fractured basaltic intrusions presented a high-quality oil reservoir well-sealed by the thick Rudeis Formation. Oil production has doubled since the discovery of this reservoir. This study introduces a novel approach to understanding the distribution pattern of basaltic intrusions in subsurface and surface analogs, which can serve as a model for exploring new potential unconventional basaltic reservoirs in the Gulf of Suez rift basin

    Negative Predictive Value of Multiparametric Magnetic Resonance Imaging in the Detection of Clinically Significant Prostate Cancer in the Prostate Imaging Reporting and Data System Era: A Systematic Review and Meta-analysis

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    CONTEXT: Prebiopsy multiparametric magnetic resonance imaging (mpMRI) is increasingly used in prostate cancer diagnosis. The reported negative predictive value (NPV) of mpMRI is used by some clinicians to aid in decision making about whether or not to proceed to biopsy. OBJECTIVE: We aim to perform a contemporary systematic review that reflects the latest literature on optimal mpMRI techniques and scoring systems to update the NPV of mpMRI for clinically significant prostate cancer (csPCa). EVIDENCE ACQUISITION: We conducted a systematic literature search and included studies from 2016 to September 4, 2019, which assessed the NPV of mpMRI for csPCa, using biopsy or clinical follow-up as the reference standard. To ensure that studies included in this analysis reflect contemporary practice, we only included studies in which mpMRI findings were interpreted according to the Prostate Imaging Reporting and Data System (PIRADS) or similar Likert grading system. We define negative mpMRI as either (1) PIRADS/Likert 1-2 or (2) PIRADS/Likert 1-3; csPCa was defined as either (1) Gleason grade group ≥2 or (2) Gleason grade group ≥3. We calculated NPV separately for each combination of negative mpMRI and csPCa. EVIDENCE SYNTHESIS: A total of 42 studies with 7321 patients met our inclusion criteria and were included for analysis. Using definition (1) for negative mpMRI and csPCa, the pooled NPV for biopsy-naïve men was 90.8% (95% confidence interval [CI] 88.1-93.1%). When defining csPCa using definition (2), the NPV for csPCa was 97.1% (95% CI 94.9-98.7%). Calculation of the pooled NPV using definition (2) for negative mpMRI and definition (1) for csPCa yielded the following: 86.8% (95% CI 80.1-92.4%). Using definition (2) for both negative mpMRI and csPCa, the pooled NPV from two studies was 96.1% (95% CI 93.4-98.2%). CONCLUSIONS: Multiparametric MRI of the prostate is generally an accurate test for ruling out csPCa. However, we observed heterogeneity in the NPV estimates, and local institutional data should form the basis of decision making if available. PATIENT SUMMARY: The negative predictive values should assist in decision making for clinicians considering not proceeding to biopsy in men with elevated age-specific prostate-specific antigen and multiparametric magnetic resonance imaging reported as negative (or equivocal) on Prostate Imaging Reporting and Data System/Likert scoring. Some 7-10% of men, depending on the setting, will miss a diagnosis of clinically significant cancer if they do not proceed to biopsy. Given the institutional variation in results, it is of upmost importance to base decision making on local data if available

    Antimicrobial resistance among migrants in Europe: a systematic review and meta-analysis

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    BACKGROUND: Rates of antimicrobial resistance (AMR) are rising globally and there is concern that increased migration is contributing to the burden of antibiotic resistance in Europe. However, the effect of migration on the burden of AMR in Europe has not yet been comprehensively examined. Therefore, we did a systematic review and meta-analysis to identify and synthesise data for AMR carriage or infection in migrants to Europe to examine differences in patterns of AMR across migrant groups and in different settings. METHODS: For this systematic review and meta-analysis, we searched MEDLINE, Embase, PubMed, and Scopus with no language restrictions from Jan 1, 2000, to Jan 18, 2017, for primary data from observational studies reporting antibacterial resistance in common bacterial pathogens among migrants to 21 European Union-15 and European Economic Area countries. To be eligible for inclusion, studies had to report data on carriage or infection with laboratory-confirmed antibiotic-resistant organisms in migrant populations. We extracted data from eligible studies and assessed quality using piloted, standardised forms. We did not examine drug resistance in tuberculosis and excluded articles solely reporting on this parameter. We also excluded articles in which migrant status was determined by ethnicity, country of birth of participants' parents, or was not defined, and articles in which data were not disaggregated by migrant status. Outcomes were carriage of or infection with antibiotic-resistant organisms. We used random-effects models to calculate the pooled prevalence of each outcome. The study protocol is registered with PROSPERO, number CRD42016043681. FINDINGS: We identified 2274 articles, of which 23 observational studies reporting on antibiotic resistance in 2319 migrants were included. The pooled prevalence of any AMR carriage or AMR infection in migrants was 25·4% (95% CI 19·1-31·8; I2 =98%), including meticillin-resistant Staphylococcus aureus (7·8%, 4·8-10·7; I2 =92%) and antibiotic-resistant Gram-negative bacteria (27·2%, 17·6-36·8; I2 =94%). The pooled prevalence of any AMR carriage or infection was higher in refugees and asylum seekers (33·0%, 18·3-47·6; I2 =98%) than in other migrant groups (6·6%, 1·8-11·3; I2 =92%). The pooled prevalence of antibiotic-resistant organisms was slightly higher in high-migrant community settings (33·1%, 11·1-55·1; I2 =96%) than in migrants in hospitals (24·3%, 16·1-32·6; I2 =98%). We did not find evidence of high rates of transmission of AMR from migrant to host populations. INTERPRETATION: Migrants are exposed to conditions favouring the emergence of drug resistance during transit and in host countries in Europe. Increased antibiotic resistance among refugees and asylum seekers and in high-migrant community settings (such as refugee camps and detention facilities) highlights the need for improved living conditions, access to health care, and initiatives to facilitate detection of and appropriate high-quality treatment for antibiotic-resistant infections during transit and in host countries. Protocols for the prevention and control of infection and for antibiotic surveillance need to be integrated in all aspects of health care, which should be accessible for all migrant groups, and should target determinants of AMR before, during, and after migration. FUNDING: UK National Institute for Health Research Imperial Biomedical Research Centre, Imperial College Healthcare Charity, the Wellcome Trust, and UK National Institute for Health Research Health Protection Research Unit in Healthcare-associated Infections and Antimictobial Resistance at Imperial College London
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