268 research outputs found

    A case report of Enteritis Redmouth Disease in cultured rainbow trout (Oncorhynchus mykiss) in Kohkyloyeh va Boyerahmad Province in Iran

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    An unknown mortality was occurred in some ponds of a farm in an area of Kohgiloyeh-&- Boyerahmad province. Three ponds showed the highest mortality rate, about 5 to 20 dead fish were reported daily for 45 days. Afflicted fish have darkening in the skin and swimming near surface or at the floor of pond and swam unmatched with flock. Some fish showed hemorrhages around and within the oral cavity and exophthalmia occasionally. About 45 moribund rainbow trout were sampled for dissection and bacteriological examination. Kidney, liver and spleen of the fishes were examined for the detection and identification of bacteria causative agent of disease in rainbow trout. They cultivated aseptically on different media (Blood Agar, Tryptic soy Agar, TCBS Agar and MacConkey Agar). All fish have been infected and suffered septicemia. A type of gram's negative bacteria was responsible of infection and mix infection was not confirmed. The bacterium was being able to grow on Mac Conkey agar. It was a bacterium very similar with Yersinia ruckeri which induced infection. Detection was based on clinical finding and bacteriological laboratory results so using of some confirmation methods such as FAT or PCR would be recommended strongly

    Effect of tooth profile modification on the durability of planetary hub gears

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    Planetary systems offer the advantage of desired speed-torque variation with a lighter, compact and coaxial construction than the traditional gear trains. Frictional losses and Noise, Vibration and Harshness (NVH) refinement are the main concerns. Modification of gear teeth geometry to reduce friction between the mating teeth flanks of vehicular planetary hubs, as well as refining NVH under varying load-speed conditions is one of the remedial actions. However, implementing modifications can result in reduced structural integrity and system durability. Therefore, a contradiction may arise between assuring a high degree of durability and achieving better transmission efficiency, which necessitates detailed system optimisation. An integrated multi-disciplinary analytical approach, including tribology and sub-surface stress analysis is developed. As a preliminary step, Tooth Contact Analysis (TCA) is performed to obtain contact footprint shape of meshing gear teeth pairs, as well as contact kinematics and applied load distribution. Then, an analytical time-efficient Elastohydrodynamic Lubrication (EHL) analysis of elliptical point contact of crowned spur gear tooth is carried out to observe the effect of gear tip relief modification upon planetary hub sub-surface stresses

    Effects of energy drinks on blood pressure, heart rate, and electrocardiographic parameters: An experimental study on healthy young adults

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    Objective: To evaluate the effects of the consumption of energy drinks on cardiovascular parameters in a group of healthy young individuals. Methods: In a quasi-experimental study, 44 healthy adult participants aged between 15 and 30 years were evaluated. The blood pressure (BP) as well as electrocardiographic indices, including heart rate (HR), PR interval, QRS duration, corrected QT (QTc) interval, and ST-T changes were recorded before consumption of a caffeine-containing energy drink and at the specific time points over a 4-h test duration. Results: We found statistically significant HR decline (p=0.004) and more frequent ST-T changes (p=0.004) after the participants consumed the energy drink. However, readings for systolic BP (p=0.44), diastolic BP (p=0.26), PR interval (p=0.449), QRS duration (p=0.235), and QTc interval (p=0.953) showed no significant change post-consumption. Conclusion: In conclusion, we demonstrated that the consumption of energy drinks could contribute to HR decline and ST-T change in healthy young adults. © 2016 by Turkish Society of Cardiology

    Calculation of the kinematics of hypoid gears towards developing a method for an equivalent crossed helical gear pair selection for use in tribological experimental evaluations

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    To experimentally verify power loss and friction for hypoid gears, measurements in a closed power-loop test rig are necessary. However, these are costly and mechanically complex, since they require additional spur gear reducers in the loop. ISO directives document the use of crossed helical gear pairs as virtual gears for hypoids to calculate the sliding velocity since, the flank geometry at the mean point can be precisely represented. The use of such pairs can be a cost effective and simpler alternative for testing purposes. However, the validity of this analogy regarding contact mechanics and tribology for the full mesh cycle has not been investigated hitherto. In the current study a new method for calculating the sliding and rolling speed along the full path of contact of a hypoid gear pair is presented. Cutter kinematics are considered, for the accurate definition of the contact bodies. Using TCA, the load distribution on the tooth under quasi-static conditions and the sliding velocity are calculated for comparison purposes. By applying a selection algorithm, a single experimental crossed helical gear pair is chosen aiming to simulate the contact conditions of hypoid gears. Two test scenarios are studied using EHL film thickness equations and friction models for evaluating the power loss. The contact is an elongated ellipse with varying directions of the sliding and sum velocities, which are considered in the model. The kinematic equivalence shows good agreement while the tribological equivalence is achievable using a reduced input torque

    Enhancement of thermal and mechanical stabilities of silicon doped titanium nitride coating by manipulation of sputtering conditions

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    This study investigates the influence of substrate (AISI M42 tool steel) bias voltage (from −30 to −80 V), on the mechanical properties of magnetron sputtered TiSiN coating derived from Ti and Si targets. Thermal stability, microstructure (crystallite size, microstrain, lattice constant), morphology and mechanical (hardness, Young's modulus, residual stresses) properties, of the deposited TiSiN coatings, were investigated with synchrotron powered X-ray diffraction (SR-XRD), X-ray photoelectron spectroscopy, field emission scanning electron microscopy, and nanoindentation techniques. Rietveld analysis, of the in-situ SR-XRD, in the temperature range of 25–800 °C, demonstrated cubic TiN form in (Ti,Si)N solid solutions, with TiO2 and Ti2O3 identified at lower bias voltages. Density functional theory supplemented the experimental results. Increase in the bias voltage resulted in: (i) a decrease in Si content, (ii) significant smoothening of surface morphology, (iii) change in the phase composition and microstructure, (iv) improved oxidation resistance and thermal oxidation threshold, and (v) hardness and Young's modulus of the coatings increased up to 50% to 33 GPa and 450 GPa, respectively

    Quality assessment of services provided by health centers in Mashhad, Iran: SERVQUAL versus HEALTHQUAL scales

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    Background: Primary health care is the entry point to the health-care system and regarded as an essential step to achieving universal health coverage. The present study aimed at evaluating the quality of health-care services provided in health centers in Mashhad, Iran. Methods: This was a cross-sectional study implemented among 200 health service users who were referring to four health centers in Mashhad during January to June 2019. The quality of services in health centers was evaluated with the SERVQUAL and HEALTHQUAL models. Data was analyzed by employing paired t-test and independent sample t-test using SPSS version 16 software. The Levene test was used for examining the equality of variance (homogeneity). Significance level of all the tests was considered when p � 0.05. Results: According to the results of SERVQUAL questionnaire, the average scores of health service users� expectations and perceptions were 4.97 and 3.26, respectively, and the quality gap in the provided services was equal to � 1.7. Based on HEALTHQUAL questionnaire, the average scores of health service users� perception and expectations were 4.72 and 3.25, respectively, and the quality gap in the provided services was equal to � 1.16. Empathy was the highest quality dimension (� 2.019) based on SERVQUAL model, and efficiency dimension was the highest based on HEALTHQUAL model (� 1.761). Conclusions: The findings of the current study showed a negative gap between the service users� expectations and perceptions in both models. Therefore, the results of this study helps the health managers and policymakers to plan effective interventions for improving the provided services emphasizing the dimensions with the wider gaps. © 2021, The Author(s)

    Evaluation of phenotypic and genotypic characteristics of carbapnemases-producing enterobacteriaceae and its prevalence in a referral hospital in Tehran city

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    Background & Objective: Carbapenem-resistant Enterobacteriaceae is a growing concern worldwide including Iran. The emergence of this pathogen is worrying as carbapenem is one of the �last-line� antibiotics for treatment of infections caused by multi drug resistant gram- negative bacteria. The main objective of this study was to determine the prevalence of carbapenem-resistant Enterobacteriaceae in a referral hospital in Tehran, Iran. Methods: In this study, all positive isolates of Enterobacteriaceae recorded in blood, urine, and other body fluids were studied during April 2017 to April 2018 in a referral hospital in Tehran. All cases of resistance to carbapenems were first tested by modified Hodge test. All cases with positive or negative test, after gene extraction, were examined genotypically based on the primers designed for the three Klebsiella pneumoniae carbapenemase (KPC), New Delhi metallo-β-lactamase (NDM), and OXA-48 genes by conventional PCR method. Results: 108 isolates (13.6) were resistant to all cephalosporins as well as to imipenem and meropenem. In a genotypic study, including 45 isolates, 13 isolates were positive for OXA-48 gene, 11 isolates for OXA-48 and NDM genes, 11 isolates for OXA-48, NDM and KPC genes, 4 isolates for OXA-48 genes and KPC, 3 isolates for NDM, one isolate for KPC. On the other hand, two isolates were negative for all three genes examined. Conclusion: OXA-48 gene was one of the most common genes resistant to carbapenems in Iran. According to studies, the prevalence of antibiotic resistance in Iran is rising dramatically, which reduces the choice of antibiotics to treat severe infections in the future. © 2020, Iranian Society of Pathology. All rights reserved

    The Effect of Citrus Aurantium Aroma on Sleep Quality in the Elderly with Heart Failure

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    BACKGROUND AND OBJECTIVE: Poor sleep quality is one of the most common problems in the elderly with heart failure, and hospitalization exacerbates this problem. In traditional Persian medicine, citrus aurantium has been recognized as a sedative and inducer of sleep. The aim of this study was to determine the effect of citrus aurantium on sleep quality in the elderly with heart failure. METHODS: This randomized clinical trial was performed on 80 elderly patients with heart failure admitted in selected teaching hospitals of Mazandaran province in two intervention and control groups. In the intervention group, aromatherapy with two drops of 10 citrus aurantium essential oil was performed on a cotton ball for twenty minutes for three consecutive nights and the control group received routine care. Sleep quality of the elderly was assessed before and after the intervention using the standard St. Mary's Hospital Sleep Questionnaire (SMHSQ) (which assesses the quality of previous night's sleep in hospitalized patients).   FINDINS: The mean sleep disorder in the elderly before and after the intervention in the intervention group was 24.70±3.67 and 21.05±3.62, respectively, which was statistically significant (p=0.001). Mean sleep disorder in the elderly before and after the intervention in the control group was 24.37±4.48 and 23.75±4.71, respectively, which was not statistically significant. CONCLUSION: The results showed that using aromatherapy with citrus aurantium can improve sleep quality in the elderly with heart failure

    Casimir type effects for scalar fields interacting with material slabs

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    We study the field theoretical model of a scalar field in presence of spacial inhomogeneities in form of one and two finite width mirrors (material slabs). The interaction of the scalar field with the defect is described with position-dependent mass term. For the single layer system we develop a rigorous calculation method and derive explicitly the propagator of the theory, S-matrix elements and the Casimir self-energy of the slab. Detailed investigation of particular limits of self-energy is presented, and connection to know cases is discussed. The calculation method is found applicable to the two mirrors case as well. By means of it we derive the corresponding Casimir energy and analyze it. For particular values of the parameters of the model the obtained results recover the Lifshitz formula. We also propose a procedure to obtain unambiguously the finite Casimir \textit{self}-energy of a single slab without reference to any renormalizations. We hope that our approach can be applied to calculation of Casimir self-energies in other demanded cases (such as dielectric ball, etc.)Comment: 22 pages, 3 figures, published version, significant changes in Section 4.

    Correlation of higher order aberrations and components of astigmatism in myopic refractive surgery candidates

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    Purpose To evaluate the correlation between refractive, corneal, and residual astigmatism and higher order aberrations (HOA) in refractive surgery candidates. Methods Three hundred and seventy-five eyes of 188 patients aged 28.2 ± 6.24 years with a predominance of females (62.7) were enrolled in this study. Refraction, topography (Orbscan IIz, Bausch & Lomb, Rochester, NY, USA), and aberrometry (Zywave, Bausch & Lomb, Rochester, NY, USA) were performed to determine refractive and corneal astigmatism and HOA for all participants. Ocular residual astigmatism was calculated using vector analysis. Results The mean spherical equivalent was �3.59 ± 1.95 D and the mean refractive astigmatism was �1.97 ± 1.3 D. The mean HOA was 0.38 ± 0.15 μm in all cases, which increased with spherical equivalent (p < 0.05). There was a positive significant correlation between both corneal and refractive astigmatism and HOA (p < 0.05), but there was no significant correlation between residual astigmatism and HOA (p = 0.122). Conclusion The results of the study showed significant correlations between corneal and refractive astigmatisms and HOA. © 2016 Iranian Society of Ophthalmolog
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