139 research outputs found

    Plug-and-play robust voltage control of DC microgrids

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    The purpose of this paper is to explore the applicability of linear time-invariant dynamical systems with polytopic uncertainty for modeling and control of islanded dc microgrids under plug-and-play (PnP) functionality of distributed generations (DGs). We develop a robust decentralized voltage control framework to ensure robust stability and reliable operation for islanded dc microgrids. The problem of voltage control of islanded dc microgrids with PnP operation of DGs is formulated as a convex optimization problem with structural constraints on some decision variables. The proposed control scheme offers several advantages including decentralized voltage control with no communication link, transient stability/performance, PnP capability, scalability of design, applicability to microgrids with general topology, and robustness to microgrid uncertainties. The effectiveness of the proposed control approach is evaluated through simulation studies carried out in MATLAB/SimPowerSystems Toolbox

    Cytotoxicity and in vitro antioxidant potential of Quercus Brantii acorn extract and the corresponding fractions

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    The present study was mainly aimed to evaluate antioxidant activity and cytotoxicity of hydroalcoholic extract and three corresponding fractions of Quercus brantii acorn. A 70% ethyle alcohole extract of the plant were prepared and sequentially partitioned with n-hexane, chloroform, ethylacetate and n-butanol. The antioxidant potential of all these fractions was evaluated by the 2,2 diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging activity method. Cytotoxic activity was tested against two normal cell lines (African green monkey kidney [Vero] and human dermal fibroblasts [HDFs]) by MTT assay. The results revealed that the n-butanol fraction exhibited the lowest IC50value (6.5±0.6 μg/ml) with the highest antioxidant activity as compared to the other fractions. The IC50values of the chloroform fraction, the n-butanol fraction, the crude extract, and the n-hexane fraction were found to be significant (p<0.05) as compared with butylated hydroxytoluene (BHT). The results of cytotoxicity showed that the chloroform fraction exhibited the highest cytotoxicity toward Vero and HDFs cell lines at concentration of 60.6±23 and 287.8±38 μg/ml, respectively. We conclude that at least, n-butanol fraction of this plant with high phytoconstituents and less toxicity could be a promising source of medicinally important natural compound. Our findings, therefore, suggest that overall the studied extract/fractions exhibit low cytotoxicity on normal cell lines. © 2016, International Journal of Pharmacognosy and Phytochemical Research. All Rights reserved

    Effect of sweet almond syrup versus methylphenidate in children with ADHD: A randomized triple-blind clinical trial

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    Background and purpose: Attention-deficit/hyperactivity disorder (ADHD) is one of the most common health disorders among children. Some patients do not respond to methylphenidate or cannot tolerate its side effects. Sweet almond syrup as a Persian Medicine preparation has been used for many years. This study aims to evaluate the efficacy and safety of sweet almond for ADHD children. Materials and methods: Fifty children aged 6-14 years with ADHD were recruited to the study. The participants were randomly assigned to two groups to receive either methylphenidate or sweet almond syrup. The outcomes were assessed using the Parent and Teacher ADHD Rating Scale every two weeks for 8 weeks. Results: Results showed that the two treatments had similar effects on symptom reduction in ADHD children. No significant differences were observed between the two groups (F=2.3, df=1, p=0.13, F=0.57, df=1, p=0.47). Conclusion: Sweet almond may be an effective treatment for ADHD children. © 2019 Elsevier Lt

    A modified sensitive carbon paste electrode for 5-fluorouracil based using a composite of praseodymium erbium tungstate

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    This paper describes the modification of a modified carbon paste electrode (CPE) using nanoparticles of praseodymium erbium tungstate (Pr:Er). The modified electrode was used for the sensitive voltammetric detection of an anticancer drug (5-fluorouracil (5-FU)) using. The modified-CPE was evaluated using cyclic voltammetry (CV), square wave voltammetry (SWV) and electrochemical impedance spectroscopy (EIS) and the resulting data showed the irreversible 5-fluorouracil oxidation peak around 1.0 V vs. Ag/AgCl. Some key parameters such as pH, the amount of the modifier, potential amplitude, step potential and frequency were studied and optimized. The square wave voltammetry (SWV) analytical calibration curve was linear in the range of 0.01�50 μM, with a detection limit of 0.98 nM analyses. The electron transfer coefficient (α) was also determined to be 0.76. The analyte concentration was also determined in pharmaceutical formulations and recovery percentages were found to be in the range of 96�102. The sensor had good reproducibility and repeatability with acceptable RSD values of 3.6, and 1.02 and a rather long-term stability of around one month. The as-synthesized nanoparticles were also characterized using FESEM, TEM, FTIR and XRD techniques. © 2020 Elsevier B.V

    Long term follow up study on a large group of patients with congenital factor XIII deficiency treated prophylactically with fibrogammin P®

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    Factor XIII deficiency (FXIIID) is an extremely rare hemorrhagic disorder with a prevalence of 1/3-5 million. Management of disease is performed by fresh frozen plasma (FFP), Cryoprecipitate (CP) or FXIII concentrate (Fibrogammin P®). Our objective was to assess safety and effectiveness of Fibrogammin P® in patients with FXIIID. For this purpose we designed this long-term follow up study on a large group of patients with FXIIID. This prospective study was conducted on 213 patients with FXIIID since 2009 to 2013. Administrated dose for Fibrogammin P® according to clinical situations of patients ranged from 10 to 26 IU/kg every 4-6 weeks. All patients in 6-month intervals were checked for human immunodeficiency virus (HIV), hepatitis A, B and C viruses (HAV, HBV, HCV). Twelve percent of participants had at least one ICH episode until 2008 but after administration of Fibrogammin P® did not have any major bleeding or episode of ICH, except in one patient. We also had 7 females with recurrent miscarriage that were managed successfully with a dose of 10 to 26 IU/kg every 4-6 weeks. This dose also was quite successful in management of major and minor surgery. None of the participants showed allergic reaction during treatment. A total of 7155450 IU of Fibrogammin P® were infused but nobody was positive for HIV, HAV, HBV, and HCV. We found that Fibrogammin P® is a safe and effective therapeutic choice in management of FXIIID. © 2016 by School of Pharmacy

    Electromigration-Induced Flow of Islands and Voids on the Cu(001) Surface

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    Electromigration-induced flow of islands and voids on the Cu(001) surface is studied at the atomic scale. The basic drift mechanisms are identified using a complete set of energy barriers for adatom hopping on the Cu(001) surface, combined with kinetic Monte Carlo simulations. The energy barriers are calculated by the embedded atom method, and parameterized using a simple model. The dependence of the flow on the temperature, the size of the clusters, and the strength of the applied field is obtained. For both islands and voids it is found that edge diffusion is the dominant mass-transport mechanism. The rate limiting steps are identified. For both islands and voids they involve detachment of atoms from corners into the adjacent edge. The energy barriers for these moves are found to be in good agreement with the activation energy for island/void drift obtained from Arrhenius analysis of the simulation results. The relevance of the results to other FCC(001) metal surfaces and their experimental implications are discussed.Comment: 9 pages, 13 ps figure

    Monitoring of Cochlodinium sp for shrimp farms in Hormozgan Province

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    The Blooming due to the some species of phytoplanktons especially Dynoflagellates has made some problems for water ecosystems and aquaculture. In this study, the density of phytoplanktons specially Cochlodinium sp. and also environmental factors such as temperature, pH, dissolved Oxygen, and transparency were recorded two weekly in 18 stations of Hormozgan province, Iran in order to monitoring of the possibility of phytoplankton blooming. During six months monitoring, the target phytoplankton, Cochlodinium sp was not observed in shrimp farms. But, other phytoplanktons and zooplanktons were observed as follow: 13 genus of phytoplankton and six genuses of zooplanktons has found in ponds, main water channel and sea. The diatoms with 10 genuses had the highest abundance and Dynoflagellates with 3 genuses had the lowest abundance and blue-green phytoplankton with one genus was in lowest group. Totally, diatoms with 77%, Dynoflagellate with 15% and blue-green alga with 8% abundance were the main populations of planktons in the studied area

    Preliminary data on COVID-19 in patients with hemoglobinopathies : A multicentre ICET-A study

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    Objectives: This study aims to investigate, retrospectively, the epidemiological and clinical characteristics, laboratory results, radiologic findings, and outcomes of COVID-19 in patients with transfusion-dependent β thalassemia major (TM), β-thalassemia intermedia (TI) and sickle cell disease (SCD). Design: A total of 17 Centers, from 10 countries, following 9,499 patients with hemoglobinopathies, participated in the survey. Main outcome data: Clinical, laboratory, and radiologic findings and outcomes of patients with COVID-19 were collected from medical records and summarized. Results: A total of 13 patients, 7 with TM, 3 with TI, and 3 with SCD, with confirmed COVID-19, were identified in 6 Centers from different countries. The overall mean age of patients was 33.7±12.3 years (range:13-66); 9/13 (69.2%) patients were females. Six patients had pneumonia, and 4 needed oxygen therapy. Increased C-reactive protein (6/10), high serum lactate dehydrogenase (LDH; 6/10), and erythrocyte sedimentation rate (ESR; 6/10) were the most common laboratory findings. 6/10 patients had an exacerbation of anemia (2 with SCD). In the majority of patients, the course of COVID-19 was moderate (6/10) and severe in 3/10 patients. A 30-year-old female with TM, developed a critical SARS-CoV-2 infection, followed by death in an Intensive Care Unit. In one Center (Oman), the majority of suspected cases were observed in patients with SCD between the age of 21 and 40 years. A rapid clinical improvement of tachypnea/dyspnea and oxygen saturation was observed, after red blood cell exchange transfusion, in a young girl with SCD and worsening of anemia (Hb level from 9.2 g/dl to 6.1g/dl). Conclusions: The data presented in this survey permit an early assessment of the clinical characteristics of COVID 19 in different countries. 70% of symptomatic patients with COVID-19 required hospitalization. The presence of associated co-morbidities can aggravate the severity of COVID- 19, leading to a poorer prognosis irrespective of age

    Disability-adjusted life-years (DALYs) for 315 diseases and injuries and healthy life expectancy (HALE) in Iran and its neighboring countries, 1990–2015

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    BACKGROUND: Summary measures of health are essential in making estimates of health status that are comparable across time and place. They can be used for assessing the performance of health systems, informing effective policy making, and monitoring the progress of nations toward achievement of sustainable development goals. The Global Burden of Diseases, Injuries, and Risk Factors Study 2015 (GBD 2015) provides disability-adjusted life-years (DALYs) and healthy life expectancy (HALE) as main summary measures of health. We assessed the trends of health status in Iran and 15 neighboring countries using these summary measures. METHODS: We used the results of GBD 2015 to present the levels and trends of DALYs, life expectancy (LE), and HALE in Iran and its 15 neighboring countries from 1990 to 2015. For each country, we assessed the ratio of observed levels of DALYs and HALE to those expected based on socio-demographic index (SDI), an indicator composed of measures of total fertility rate, income per capita, and average years of schooling. RESULTS: All-age numbers of DALYs reached over 19 million years in Iran in 2015. The all-age number of DALYs has remained stable during the past two decades in Iran, despite the decreasing trends in all-age and age-standardized rates. The all-cause DALY rates decreased from 47,200 in 1990 to 28,400 per 100,000 in 2015. The share of non-communicable diseases in DALYs increased in Iran (from 42% to 74%) and all of its neighbors between 1990 and 2015; the pattern of change is similar in almost all 16 countries. The DALY rates for NCDs and injuries in Iran were higher than global rates and the average rate in High Middle SDI countries, while those for communicable, maternal, neonatal, and nutritional disorders were much lower in Iran. Among men, cardiovascular diseases ranked first in all countries of the region except for Bahrain. Among women, they ranked first in 13 countries. Life expectancy and HALE show a consistent increase in all countries. Still, there are dissimilarities indicating a generally low LE and HALE in Afghanistan and Pakistan and high expectancy in Qatar, Kuwait, and Saudi Arabia. Iran ranked 11th in terms of LE at birth and 12th in terms of HALE at birth in 1990 which improved to 9th for both metrics in 2015. Turkey and Iran had the highest increase in LE and HALE from 1990 to 2015 while the lowest increase was observed in Armenia, Pakistan, Kuwait, Kazakhstan, Russia, and Iraq. CONCLUSIONS: The levels and trends in causes of DALYs, life expectancy, and HALE generally show similarities between the 16 countries, although differences exist. The differences observed between countries can be attributed to a myriad of determinants, including social, cultural, ethnic, religious, political, economic, and environmental factors as well as the performance of the health system. Investigating the differences between countries can inform more effective health policy and resource allocation. Concerted efforts at national and regional levels are required to tackle the emerging burden of non-communicable diseases and injuries in Iran and its neighbors

    Tissue culture of ornamental cacti

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