231 research outputs found

    Comparative performance of optical amplifiers: Raman and EDFA

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    The in-line optical signal amplification is often used in optical communication systems to accomplish longer transmission distances and larger capacity. In this proposed paper, the operation of two types of optical amplifiers for 16Ă—10 Gbps wavelength division multiplexing system had been examined by changing transmission distance from 10 to 200 km with a dispersion equals to 16.75 ps/nm/km. The analysis and design of such systems ordinarily includes many signal channels, nonlinear devices, several topologies with many noise sources, is extremely complex and effort-exhaustive. Therefore, theoretical studies with simulation CAD software of systems are become necessity to predict and optimize system performance. The comparison between EDFA and Raman has already explored by many researchers in varying ways in this work and to achieve obove objectives, the OptiSystem software was used to design the proposed fiber optic communications system and to simulate results. Performance for the present system was evaluated for parameters like bit error rate (BER), quality factor (QF), total gain with eye opening factor. It was saw that EDFA provides better results, in the maximal transmission distance 64% better than Raman amplifier, 57.5% for gain and 26.7% for maximum quality factor. As a future study a hybrid amplifier can produce better quality of amplification

    Hardware accelerator for anti-aliasing Wu's line algorithm using FPGA

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    Digital images are suffering from the stair-step effect because they are built from small pixels. This effect termes aliasing and the method uses to decrease so-called anti-aliasing. This paper offers a hardware accelerator of an anti-aliasing algorithm using HLS (high level synthesis) along straight-line segments or edges. These straight-line segments are smoothed by modifying the intensity of the pixel. The hardware implementation of two different architectures which is based on Zynq FPGA are presented in this work. The first architecture is built from one core while the second architecture is built from multi-core and uses a parallel technique to speed up the algorithm by dividing line segments into sub-segments and drawing them after smoothing instantaneously to formulate the main line. This parallel usage leads to a very fast execution of Wu's algorithm which is represented one-tenth hardware runtime for one core only. Also, the optimized resource utilization and power consumption for different cores have been compared, through single-core design which utilizes 8% and consumes 1.6 W, while utilized resources using 10 cores are 77% with a power consumption of 2 W

    Predictors of burnout for immigrant mental health professionals in the United States

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    Mental health professionals who identify as immigrants encounter personal and professional barriers that can impact overall wellbeing. The current study conducted a survey of 108 licensed mental health professionals who identify as immigrants practicing in the United States. The survey included demographics as well as assessments of burnout, social support, and migratory grief and loss. The results of this study highlighted that a combination of higher migratory grief and lower perceived social support significantly predicted higher levels of burnout in mental health professionals. Implications for mental health programs, supervisors, and mentors and suggestions for future research are provided

    The cardioprotective effects of secoisolariciresinol diglucoside (flaxseed lignan) against cafeteria diet-induced cardiac fibrosis and vascular injury in rats: an insight into apelin/AMPK/FOXO3a signaling pathways

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    Introduction: Fast food is a major risk factor for atherosclerosis, a leading cause of morbidity and mortality in the Western world. Apelin, the endogenous adipokine, can protect against cardiovascular disease via activating its receptor, APJ. Concurrently, secoisolariciresinol diglucoside (SDG), a flaxseed lignan extract (FLE), showed a therapeutic impact on atherosclerosis. The current study aimed to examine the effect of SDG on cafeteria diet (CAFD)-induced vascular injury and cardiac fibrosis via tracking the involvement of the apelin/APJ pathway.Methods: Thirty male rats were allocated into control, FLE-, CAFD-, CAFD/FLE-, and CAFD/FLE/F13A-treated rats, where F13A is an APJ blocker. All treatments lasted for 12 weeks.Results and discussion: The CAFD-induced cardiovascular injury was evidenced by histological distortions, dyslipidemia, elevated atherogenic indices, cardiac troponin I, collagen percentage, glycogen content, and apoptotic markers. CAFD increased both the gene and protein expression levels of cardiac APJ, apelin, and FOXO3a, in addition to increasing endothelin-1, VCAM1, and plasminogen activator inhibitor-1 serum levels and upregulating cardiac MMP-9 gene expression. Moreover, CAFD reduced serum paraoxonase 1 and nitric oxide levels, cardiac AMPK, and nuclear Nrf2 expression. FLE attenuated CAFD-induced cardiovascular injury. Such effect was reduced in rats receiving the APJ blocker, implicating the involvement of apelin/APJ in FLE protective mechanisms.Conclusion: FLE supplementation abrogated CAFD-induced cardiac injury and endothelial dysfunction in an apelin/APJ-dependent manner

    Stability study of thymoquinone, carvacrol and thymol using HPLC-UV and LC-ESI-MS

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    The aim of this study was to investigate the stability of three major antioxidants of Nigella sativa: thymoquinone (TQ), carvacrol (CR) and thymol (THY), under different stress conditions using HPLC and LC-MS/MS. Forced degradation for each compound was performed under different conditions, including oxidation, hydrolysis, photolysis and thermal decomposition. The results showed that both CR and THY were stable under the studied conditions, whereas TQ was not affected by acidic, basic and oxidative forced conditions but the effect of light and heat was significant. The degradation products of TQ were further investigated and characterized by LC-MS/MS. HPLC-UV method has been fully validated in terms of linearity and range, the limit of detection and quantitation, precision, selectivity, accuracy and robustness. The method was successfully applied to quantitative analysis of the principal antioxidants of Nigella sativa TQ, CR and THY in different phytopharmaceuticals

    Phytochemical composition and antimicrobial properties of Markhamia platycalyx (Baker) Sprague leaf

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    Purpose: To isolate new antimicrobial agents from the leaves of Markhamia platycalyx (Baker) Sprague and assess their phytochemical characteristics and antimicrobial activity. Methods: Different chromatographic and spectroscopic techniques (NMR and ESI-MS) were applied for the identification of antimicrobial compounds. Agar-well diffusion technique was used for determination of antimicrobial activity. Anti-HCV effects were investigated using VITROS Anti-HCV assay. Results: Eighteen compounds were isolated for the first time from this genus. These were phytol, noctacosanoic acid (OCTA), tormentic acid and β-sitosterol-3-O-(6'-O-heptadecanoyl)-β-Dglucopyranoside. The other compounds were β-sitosterol, ursolic acid (URSA), oleanolic acids, pomolic acid (POMA), 2-epi-tormentic and β-sitosterol-3-O-β-D-glucopyranoside. However, stigmasterol and acteoside, which were seen in previous studies, were also present. Total ethanol extract (TEE) was the most effective against Escherichia coli, with the lowest minimum inhibitory concentration (MIC) of 1.0 µg/mL. Acteoside, URSA and 2-epi-tormentic acid showed the highest antibacterial effect on Pseudomonas aeruginosa while 2-epi-tormentic acid and acteoside produced the least MIC on Candida glabrata. These effects were superior to those produced by standard antibiotics. However, 2-epitormentic acid and β-sitosterol-3-O-β-D-glucopyranoside had no anti-HCV effects. Conclusion: Due to the good antimicrobial properties of Markhamia platycalyx, it is a potential source of new antimicrobial drugs

    Studies of the Precipitation Pattern of Paclitaxel in Intravenous Infusions and Rat Plasma Using Laser Nephelometry

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    Cremophor EL (CrEL) is commonly used to solubilize paclitaxel (Ptx); a widely established anticancer agent used against many types of cancer. Using laser-based microplate nephelometry, in this work we assessed the precipitation kinetics of Ptx in CrEL-containing formulations upon dilutions with different infusion media or upon introduction into rat plasma. The precipitation profile of Ptx was assessed for a Taxol-like formulation and compared with a preparation with reduced CrEL content. These two formulations were diluted at various ratios in compatible infusion media and with or without rat plasma. The percentages of Ptx precipitated in dilution media and protein-binding in plasma were quantified using HPLC. The findings of turbidity measurements were in good agreement with HPLC. Despite the presence of albumin, it was possible to assess turbidity within infusion solutions and predict Ptx precipitation. Upon addition to plasma, no precipitation in Taxol-like formulation occurred after 2 h. In contrast, precipitation occurred immediately in CrEL-reduced formulation. It is possible that the high percentage of protein-bound Ptx in plasma (98.5–99.2%) has inhibited drug precipitation. Turbidity measurements using laser nephelometry can provide a rapid screening tool when developing intravenous formulations for poorly soluble drugs, such as Ptx and assess its stability upon dilution in animal plasma

    Aggression is a dominant behavior among adolescents in Al-Sadr city, Baghdad-Iraq

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    Background: Aggression is any behavior intending to harm another living being that desires to avoid such harm. Aggression is considered as a public health problem worldwide. Exposure to violence is a determinant of aggression. Al-Sadr city, which is an overcrowded residential area in Baghdad, was exposed to violence through wars, civil war, and widespread inter-personal violence). This situation was an impetus to study aggression in this city. Objectives: To estimate the prevalence of aggression among secondary school students in Al-Sadr city, Baghdad. Methodology: A cross-sectional study was carried out in Al-Sadr city in Baghdad. A total of 720 adolescent secondary schools students from both genders were included in the study. They were selected by multistage random sampling. Their age was ranged from 13-21 years. Data was collected from 1st of February 2019 to 30 of April 2019 through a self-reported questionnaire (Aggression-Problem Behavior Frequency Scale). Results: The mean age of participants was 16.2±2.04 years. Of all participants, 84.3% were assessed to be aggressive; including 329 (91.4%) males and 278 (77.2%) females. Males showed significantly higher aggression than females (p=0.001). Absence from school and low academic achievement were dominating among aggressive students (88.2% and 86.9%, respectively). Non-physical Aggression was the most common type of aggression (76.4%). Conclusion: A high prevalence of aggression (mainly non-physical) was found, which was significantly associated with gender, being higher among males. Aggression was negatively affecting school achievement

    STUDY THE EFFECT OF DIFFERENT OPERATING PARAMETERS ON HEAT TRANSFER COEFFICIENT IN GAS-SOLID FLUIDIZED BED USING HORIZONTAL HEAT TRANSFER PROBE

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    ABSTRACT Heat transfer studies were carried out in a laboratory scale gas-solid fluidized bed with 0.1m ID x 1 m length column, using three sizes of local sand particles of 301, 454, and 560 µm. the bed region was heated bya horizontal heat transfer probe. It was made of copper rod (15 mm ODx50 mm long) and insulated at the ends by Teflon. A hole was drilled at the center of the rod to accommodate a cartridge heater 200 W (6.5 mm OD x 42 mm long). Three bed inventories of sand 1.5 kg, 2.0 kg, and 2.5 kg, four superficial air velocities of 1.0 m/s, 1.25 m/s, 1.5 m/s, 1.75 m/s were used. Three heat fluxes of 1698.9, 2928.4, 4675.7 W m -2 were employed. The data obtained showed how the heat transfer coefficient effected by the above operating parameters. The heat transfer coefficient is directly proportional with air superficial velocity as well as the bed inventory and heat fluxes but inversely proportional with sand particles size
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