57 research outputs found

    Adaptive Voltage and Current Control to Improve Stability and Restoration of Operation after the Occurrence of a Transient Fault in The Inverter-based Standalone Microgrid

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    339-348Small signal stability analysis and control strategies are well provided for conventional power systems. Still, in inverter-based microgrids, it is necessary to determine the model features and control specific oscillation modes. In this paper, inverter-based standalone microgrid performance modelling, including voltage and current control, has been developed. This model has inverter control loop details but does not provide switching performance. A simple adaptive controller controls the microgrid voltage and current, with only three parameters, including two negatively stable feedbacks and positive unstable feedback. Advantages of this controller over a Proportional Integral Derivative (PID) controller include proper adaptation to system changes, flexibility in setting up, and a robust deal with sudden changes in the system. Finally, by making drastic changes in the operation of a sample microgrid, such as loading and short circuit faults, we prove the effectiveness of the proposed adaptive control scheme in improving the stability and restoration of operation after the occurrence of a transient fault in the microgrid

    Relief of labor pain by ice massage of the hand

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    Background: Labor pain is the worst pain experience during women's life. The management of labor pain is amongst the leading goals of maternity care. Unrelieved labor pain may adversely af ect both mother and the neonate. The aim of this study was to determine the ef ect of Hoku point ice massage on pain intensity in primiparous women during labor. Materials and Methods: A randomized controlled trial was conducted on 60 primiparous women who were expected to have normal childbirth in Hajar Hospital of Shahrekord. All participants were randomly assigned in two groups (n = 30): ice massage (treatment) and sand bag group (control). The severity of the basal pain was measured at the beginning of active phase (4 cm cervical dilation) based on Visual Analogue Scale (VAS). Then, after two groups received intervention, the severity of the labor pain in 4, 6, 8 and 10 cm cervical dilation was measured. In the case group, the crushed ice twisted in a terry bag was rocked on the web of skin between thumb and forefinger. The massage was carried out in Hoku point throughout three contractions. The sand bag tactile massage in Hoku point was served in the control group. The data were analyzed using SPSS software and descriptive analysis using Mann- Whitney, x2, paired and independent t tests and P<0.05 was considered significant. Results: After completion of intervention, the pain intensity in the treatment group was significantly less than the control group P<0.001). Also, mean duration of active phase of labor in treatment group was significantly less than the control group (P<0.05). In the treatment group, the dif erence between the mean of the pain pre and post intervention was significant just in 4, 6 and 8 cervical dilation (P<0.001). Conclusions: Regarding the ice massage as a cost-ef ective and noninvasive nursing intervention and considering high satisfaction of patients, we recommend this safe and easy-to-use technique for alleviation of the labor pain

    Possible involvement of l-arginine-nitric oxide pathway in the antidepressant activity of Auraptene in mice

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    Background: Depression is one of the most common mental illnesses worldwide. Nitric oxide (NO) is involved in the pathophysiology of depression. Auraptene (a coumarin derivative) has been shown to possess pharmacological effects on neurological diseases. Purpose: The present study aimed to investigate the possible role of the NO pathway in Auraptene antidepressant effects in male mice. Methods: Behavioral tests were used to assess depression-like behaviors. The mice received Auraptene at 10, 30, and 100 mg/kg, the combination of the sub-effective (ineffective) dose of Auraptene (10 mg/kg) and L-NAME, and the combination of the effective dose of Auraptene (30 mg/kg) and L-arginine. Finally, OFT, TST, FST, brain, serum MDA level, antioxidant capacity, hippocampus, and serum NO level were measured. Results: The data analysis showed that Auraptene (30 mg/kg) improved depression-like behaviors. Auraptene (30 mg/kg) also significantly reduced serum NO levels (P < 0.05) and significantly increased serum MDA (10 mg/kg, P < 0.05). Auraptene at 30 mg/kg also increased serum antioxidant capacity (P < 0.01). Co-administration of L-NAME and the sub-effective dose of Auraptene enhanced the effects of Auraptene. However, co-administration of the effective dose of Auraptene and L-arginine reduced the impacts of Auraptene. Conclusions: The results showed that Auraptene causes antidepressant effects in a dose-dependent manner and acts as a prooxidant at 100 mg/kg, and exacerbates oxidative stress. The antidepressant effects of this active molecule are exerted by reducing the NO level in the hippocampus and serum, increasing the antioxidant capacity, and reducing the MDA level in the serum

    Anethole Ameliorates Acetic Acid-Induced Colitis in Mice: Anti-Inflammatory and Antioxidant Effects

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    Anethole has possessed anti-inflammatory and antioxidant responses in numerous studies. Oxidative stress has a pivotal role in the pathophysiology of colitis. The current study is designed to determine the effect of anethole on acetic acid-induced colitis in mice in view of its possible anti-inflammatory and antioxidant properties. In this study, 48 mice were grouped into 6 groups (n = 8), and colitis was induced with 0.2 ml of 7% acetic acid. Mice received intraperitoneally (i.p.) for 7 constant days normal saline and/or anethole at doses of 31.25, 62.5, 125, and 250 mg/kg, respectively. After treatments, the colon was dissected out, and histopathological changes, expression of inflammatory genes (IL-1 beta, TNF-alpha, and TLR4), and evaluation of malondialdehyde (MDA) levels and total antioxidant capacity (TAC) were assessed. The results showed that colitis is associated with edema and inflammatory responses in all layers and severe damage to the epithelium of the colon. Colitis causes a decrease in TAC, an increase in MDA levels, and an increase in inflammatory genes in the colon. Findings determined that anethole ameliorated the adverse effects of acetic acid-induced colitis in the colon. It is concluded that anethole, partially at least, possessed protective effects in acetic acid-induced colitis in mice through attenuation of oxidative stress and inflammatory response

    Parasitic Helminths in Wild Boars (Sus scrofa) in Mazandaran Province, Northern Iran

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    Background: Wild boars (Sus scrofa) are distributed worldwide and found in many parts of Iran. Although S. scrofa is reservoirs for many parasites, there is little data on helminthic prevalence in them. We aimed to survey the status of helminthic infections in S. scrofa in the Mazandaran Province of northern Iran. Methods: Twenty-one wild boars were captured and examined for helminth infection during Dec 2012-Mar 2014. Adult worms such as Macracanthorhynchus hirudinaceus were identified by helminth size and shape, and the arrangement of the proboscis hooks. The sedimentation and flotation techniques were used to detect parasite eggs and larvae in faecal samples. Muscle samples were also surveyed for Trichinella larvae by artificial digestion method. Results: Of the 21 samples, 13 (61.9%) were infected with one or more helminth species. Seven helminth types were identified in the alimentary track, comprising 5 nematodes, 1 trematode, and 1 acanthocephalan, with prevalence rates of Macracanthorhynchus hirudinaceus (57.14%), Globocephalus spp. (33.33%), Trichuris suis (19.04), Gongylonema pulchrum (14.28%), Fasciola hepatica (14.28%), Dioctophyma renale (4.76%), and Ascaris suum (4.76%). Conclusion: Wild boars might be involved in transmitting zoonotic parasites to humans. The abundance of these animals near human habitation creates favorable conditions for infection. So the risk of parasitic helminth diseases increases in other animals and humans

    A Case Based-Shared Teaching Approach in Undergraduate Medical Curriculum: A Way for Integration in Basic and Clinical Sciences

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    To present a multiple-instructor, active-learning strategy in the undergraduate medical curriculum. This educational research is a descriptive one. Shared teaching sessions, were designed for undergraduate medical students in six organ-system based courses. Sessions that involved in-class discussions of integrated clinical cases were designed implemented and moderated by at least 3 faculties (clinicians and basic scientists). The participants in this study include the basic sciences medical students of The Tehran University of Medical Sciences. Students’ reactions were assessed using an immediate post-session evaluation form on a 5-point Likert scale. Six two-hour sessions for 2 cohorts of students, 2013 and 2014 medical students during their two first years of study were implemented from April 2014 to March 2015. 17 faculty members participated in the program, 21 cases were designed, and participation average was 60 % at 6 sessions. Students were highly appreciative of this strategy. The majority of students in each course strongly agreed that this learning practice positively contributed to their learning (78%) and provided better understanding and application of the material learned in an integrated classroom course (74%). They believed that the sessions affected their view about medicine (73%), and should be continued in future courses (80%). The percentage demonstrates the average of all courses. The program helped the students learn how to apply basic sciences concepts to clinical medicine. Evaluation of the program indicated that students found the sessions beneficial to their learning

    Transfusion-transmitted malaria : a systematic review and meta-analysis

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    Background : Malaria transmission through blood transfusion is an accidental but preventable cause of malaria infection and is increasingly becoming a matter of concern for blood transfusion services. This systematic review was conducted to provide a summary of evidence about the prevalence of Plasmodium infection in asymptomatic blood donors and the effectiveness of screening methods used based on the available literature. Methods : PRISMA guidelines were followed. Scopus, PubMed, Science Direct, and EMBASE were searched from 1982 to October 10, 2017. All peer-reviewed original research articles describing the prevalence of malaria parasitemia in blood donors with different diagnostic methods were included. The random-effects model was applied to assess the effects of heterogeneity among the selected studies. Incoherence and heterogeneity between studies were quantified by I2 index and Cochran's Q test. Publication and population bias was assessed with funnel plots and Egger's regression asymmetry test. All statistical analyses were performed using Stata (version 2.7.2). Results : Seventy-one studies from 21 countries, 5 continents, were included in the present systematic review. The median prevalence of malaria parasitemia among 984 975 asymptomatic healthy blood donors was 10.54%, 5.36%, and 0.38% by microscopy, molecular methods (polymerase chain reaction), and rapid diagnostic tests, respectively. The most commonly detected Plasmodium species was P. falciparum. Conclusions : This systematic review demonstrates that compared with other transfusion-linked infections, that is, HIV, HCV, and HBV, transfusion-transmitted malaria is one of the most significant transfusion-associated infections especially in Sub-Saharan Africa. Future work must aim to understand the clinical significance of transfusion-transmitted malaria in malaria-endemic settings.Publisher PDFPeer reviewe

    Mapping local patterns of childhood overweight and wasting in low- and middle-income countries between 2000 and 2017

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    A double burden of malnutrition occurs when individuals, household members or communities experience both undernutrition and overweight. Here, we show geospatial estimates of overweight and wasting prevalence among children under 5 years of age in 105 low- and middle-income countries (LMICs) from 2000 to 2017 and aggregate these to policy-relevant administrative units. Wasting decreased overall across LMICs between 2000 and 2017, from 8.4% (62.3 (55.1–70.8) million) to 6.4% (58.3 (47.6–70.7) million), but is predicted to remain above the World Health Organization’s Global Nutrition Target of <5% in over half of LMICs by 2025. Prevalence of overweight increased from 5.2% (30 (22.8–38.5) million) in 2000 to 6.0% (55.5 (44.8–67.9) million) children aged under 5 years in 2017. Areas most affected by double burden of malnutrition were located in Indonesia, Thailand, southeastern China, Botswana, Cameroon and central Nigeria. Our estimates provide a new perspective to researchers, policy makers and public health agencies in their efforts to address this global childhood syndemic

    Global burden of 369 diseases and injuries in 204 countries and territories, 1990–2019: a systematic analysis for the Global Burden of Disease Study 2019

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    Background: In an era of shifting global agendas and expanded emphasis on non-communicable diseases and injuries along with communicable diseases, sound evidence on trends by cause at the national level is essential. The Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) provides a systematic scientific assessment of published, publicly available, and contributed data on incidence, prevalence, and mortality for a mutually exclusive and collectively exhaustive list of diseases and injuries. Methods: GBD estimates incidence, prevalence, mortality, years of life lost (YLLs), years lived with disability (YLDs), and disability-adjusted life-years (DALYs) due to 369 diseases and injuries, for two sexes, and for 204 countries and territories. Input data were extracted from censuses, household surveys, civil registration and vital statistics, disease registries, health service use, air pollution monitors, satellite imaging, disease notifications, and other sources. Cause-specific death rates and cause fractions were calculated using the Cause of Death Ensemble model and spatiotemporal Gaussian process regression. Cause-specific deaths were adjusted to match the total all-cause deaths calculated as part of the GBD population, fertility, and mortality estimates. Deaths were multiplied by standard life expectancy at each age to calculate YLLs. A Bayesian meta-regression modelling tool, DisMod-MR 2.1, was used to ensure consistency between incidence, prevalence, remission, excess mortality, and cause-specific mortality for most causes. Prevalence estimates were multiplied by disability weights for mutually exclusive sequelae of diseases and injuries to calculate YLDs. We considered results in the context of the Socio-demographic Index (SDI), a composite indicator of income per capita, years of schooling, and fertility rate in females younger than 25 years. Uncertainty intervals (UIs) were generated for every metric using the 25th and 975th ordered 1000 draw values of the posterior distribution. Findings: Global health has steadily improved over the past 30 years as measured by age-standardised DALY rates. After taking into account population growth and ageing, the absolute number of DALYs has remained stable. Since 2010, the pace of decline in global age-standardised DALY rates has accelerated in age groups younger than 50 years compared with the 1990–2010 time period, with the greatest annualised rate of decline occurring in the 0–9-year age group. Six infectious diseases were among the top ten causes of DALYs in children younger than 10 years in 2019: lower respiratory infections (ranked second), diarrhoeal diseases (third), malaria (fifth), meningitis (sixth), whooping cough (ninth), and sexually transmitted infections (which, in this age group, is fully accounted for by congenital syphilis; ranked tenth). In adolescents aged 10–24 years, three injury causes were among the top causes of DALYs: road injuries (ranked first), self-harm (third), and interpersonal violence (fifth). Five of the causes that were in the top ten for ages 10–24 years were also in the top ten in the 25–49-year age group: road injuries (ranked first), HIV/AIDS (second), low back pain (fourth), headache disorders (fifth), and depressive disorders (sixth). In 2019, ischaemic heart disease and stroke were the top-ranked causes of DALYs in both the 50–74-year and 75-years-and-older age groups. Since 1990, there has been a marked shift towards a greater proportion of burden due to YLDs from non-communicable diseases and injuries. In 2019, there were 11 countries where non-communicable disease and injury YLDs constituted more than half of all disease burden. Decreases in age-standardised DALY rates have accelerated over the past decade in countries at the lower end of the SDI range, while improvements have started to stagnate or even reverse in countries with higher SDI. Interpretation: As disability becomes an increasingly large component of disease burden and a larger component of health expenditure, greater research and developm nt investment is needed to identify new, more effective intervention strategies. With a rapidly ageing global population, the demands on health services to deal with disabling outcomes, which increase with age, will require policy makers to anticipate these changes. The mix of universal and more geographically specific influences on health reinforces the need for regular reporting on population health in detail and by underlying cause to help decision makers to identify success stories of disease control to emulate, as well as opportunities to improve. Funding: Bill & Melinda Gates Foundation. © 2020 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 licens
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