136 research outputs found
Modelling and Simulation of Fuel Cell Dynamics for Electrical Energy Usage of Hercules Airplanes
Dynamics of proton exchange membrane fuel cells (PEMFC) with hydrogen storage system for generating part of Hercules airplanes electrical energy is presented. Feasibility of using fuel cell (FC) for this airplane is evaluated by means of simulations. Temperature change and dual layer capacity effect are considered in all simulations. Using a three-level 3-phase inverter, FC’s output voltage is connected to the essential bus of the airplane. Moreover, it is possible to connect FC’s output voltage to airplane DC bus alternatively. PID controller is presented to control flow of hydrogen and oxygen to FC and improve transient and steady state responses of the output voltage to load disturbances. FC’s output voltage is regulated via an ultracapacitor. Simulations are carried out via MATLAB/SIMULINK and results show that the load tracking and output voltage regulation are acceptable. The proposed system utilizes an electrolyser to generate hydrogen and a tank for storage. Therefore, there is no need for batteries. Moreover, the generated oxygen could be used in other applications in airplane
Antimicrobial effects of Kelussia odoratissima extracts against food borne and food spoilage bacteria "in vitro"
The aim of this paper was to investigate the antibacterial potential of Kelussia odoratissima Mozff extract against Gram-negative and Gram-positive bacteria. Karafs-eKoohi with the scientific name of Kelussia odoratissima is an Iranian endemic edible plant in the middle region of Iran with enormous use as food, spice and medicinal herb. The antibacterial effect of the extracts was investigated using pour plate and disk diffusion methods. Minimum Inhibitory Concentration (MIC( and Minimum Bactericidal Concentration (MBC) were also studied using the dilution method. Repeated measure ANOVA was used for data analysis. The results showed that in disk diffusion method all concentrations of ethanolic extract had inhibitory effect against Bacillus subtilis and Staphylococcus aureus. Minimum Inhibitory Concentration (MIC( of Kelussia odoratissima leaves of aqueous and ethanolic extracts for Bacillus subtilis and Staphylococcus aureus were 16 and 8 mg/ml, and for Enterobacter aerogenes were 32 and 16 mg/ml, respectively. Minimum Bactericidal Concentration (MBC) of Kelussia odoratissima leaves of aqueous and ethanolic extracts for Bacillus subtilis and Staphylococcus aureus were 32 and 16 mg/ml, and for Enterobacter aerogenes were 64 and 32mg/ml, respectively. The results showed that the extract of Kelussia odoratissima had a satisfactory antimicrobial activity and the ethanolic extract of Kelussia odoratissima leaves had greater inhibitory effects on the strains studied compared to aqueous extract in vitro. A significant correlation was also observed between zone of inhibition and concentration of extracts
Comparison of the Components of Brainstem Auditory Responses Using Click and Chirp Stimuli in Premature Infants
Background and Objectives: Prematurity means that the baby is born before 37 months of age, which leads to various problems, including hearing defects. Timely detection of hearing loss with the help of tools that facilitate this identification, can have a significant impact on the child’s personal, social, and educational development. The aim of the present study was to achieve better responses using the chirp stimulus along with the click. The chirp stimulus can compensate for the time delay caused by low-frequency stimuli and increases the simultaneous presentation of high and low frequencies in the cochlea. Therefore, the morphology of the waves is improved, and the amplitude of responses increases; thus, the waves can be better identified despite the prematurity of the infants.
Methods: Eighy newborns were examined in four groups, which were divided into term and preterm groups based on gestational age (including late preterm, moderate, and very preterm). The intensity of the click and chirp stimuli was fixed at 40 and 80 dB. The amplitude and latency of waves I, III, and V, the inter-peak latencies of I-III, III-V, and I-V, as well as the ratio of the amplitude of wave V/I were among the compared parameters. It should be mentioned in tables paired t-test was used in cases marked with *. Wilcoxon test was used in other cases.
Results: The chirp stimulus mainly had less latency than the click stimulus and created a larger amplitude at a high intensity (80 dB). In the intensity close to the threshold, i.e. 40 dB, these findings were slightly different. The more developed the infants, the stronger the responses and the more effective the chirp stimulus in eliciting responses.
Conclusion: The chirp stimulus was more effective in obtaining multiple components of brainstem-evoked responses in infants, especially preterm infants, and investigating the status of their auditory system. The use of a higher sample size could lead to an increase in the growth of clinical use and better efficiency of diagnostic protocols and responses
Study of Diseases Associated ESR above 100 among the Patients who Visited Shahid Sadoughi Hospital in the Second half of 2013
Introduction: ESR (Erythrocyte Sedimentation Rate) is the sedimentation rate of red blood cells per unit of time that is expressed in millimeters. ESR test is simple and inexpensive and fast and can be somewhat diagnostic manual to confirm the diagnosis, rule out the diagnosis, follow-up course of the disease and so on, so it is of interest to practitioners.Methods: Descriptive and cross-sectional study on 124 patients in all wards of Shahid Sadooghi hospital in the second 6 months of 1393, that had raised ESR of 100 at least one time. All information including gender, age, diagnosis of the presence or absence of fever and indigenous of them cases in the archive hospital patients were taken.Results: 56% female and 44% were male. 16% of patients in the age range 0-19 years, 56% aged 20-64 years and 28% were aged over 64 years. 41% of patients were admitted with fever. 59% were native and 41 % were non-native. Infectious causes (45.9%), malignancy (14.5%), collagen vascular disease (16.9%), internal disease and hematology (16.9%) and other causes (5.6%) were formed cases. Diabetic foot (7%), pneumonia (7%), RA (6%), ESRD (5.6%), metastatic lung cancer (4%), TB (3%) formed the majority of cases.In feverish cases pneumonia (11.5%), diabetic foot (7.6%), tuberculosis (5.7%), pyelonephritis (5.7%) and RA (5.7%) were the most frequent form. Infectious causes of fever (65.3%), collagen vascular (13.4%), malignancies (5.7%) and other causes (15.6%).conclusion: In patients with extremely high sediment in terms of gender segregation is almost the same of hospital commiunity
Infectious Diarrhea Risks as a Public Health Emergency in Floods; a Systematic Review and Meta-Analysis
Introduction: Infectious diarrhea, a significant global health challenge, is exacerbated by flooding, a consequence of climate change and environmental disruption. This comprehensive study aims to quantify the association between flooding events and the incidence of infectious diarrhea, considering diverse demographic, environmental, and pathogen-specific factors.
Methods: In this systematic review and meta-analysis, adhering to PROSPERO protocol (CRD42024498899), we evaluated observational studies from January 2000 to December 2023. The analysis incorporated global data from PubMed, Scopus, Embase, Web of Science, and ProQuest, focusing on the relative risk (RR) of diarrhea post-flooding. The study encompassed diverse variables like age, sex, pathogen type, environmental context, and statistical modeling approaches.
Results: The meta-analysis, involving 42 high-quality studies, revealed a substantial increase (RR = 1.40, 95% CI [1.29–1.52]) in the incidence of diarrhea following floods. Notably, bacterial and parasitic diarrheas demonstrated higher RRs (1.82 and 1.35, respectively) compared to viral etiologies (RR = 1.15). A significant sex disparity was observed, with women exhibiting a higher susceptibility (RR = 1.55) than men (RR = 1.35). Adults (over 15 years) faced a greater risk than younger individuals, highlighting age-dependent vulnerability.
Conclusion: This extensive analysis confirms a significant correlation between flood events and increased infectious diarrhea risk, varying across pathogens and demographic groups. The findings highlight an urgent need for tailored public health interventions in flood-prone areas, focusing on enhanced sanitation, disease surveillance, and targeted education to mitigate this elevated risk. Our study underscores the critical importance of integrating flood-related health risks into global public health planning and climate change adaptation strategies
Dual combination therapy versus long-acting bronchodilators alone for chronic obstructive pulmonary disease (COPD) : A systematic review and network meta-analysis
Background: Long-acting bronchodilators such as long-acting β-agonist (LABA), long-acting muscarinic antagonist (LAMA), and LABA/inhaled corticosteroid (ICS) combinations have been used in people with moderate to severe chronic obstructive pulmonary disease (COPD) to control symptoms such as dyspnoea and cough, and prevent exacerbations. A number of LABA/LAMA combinations are now available for clinical use in COPD. However, it is not clear which group of above mentioned inhalers is most effective or if any specific formulation works better than the others within the same group or class. Objectives: To compare the efficacy and safety of available formulations from four different groups of inhalers (i.e. LABA/LAMA combination, LABA/ICS combination, LAMA and LABA) in people with moderate to severe COPD. The review will update previous systematic reviews on dual combination inhalers and long-acting bronchodilators to answer the questions described above using the strength of a network meta-analysis (NMA). Search methods: We identified studies from the Cochrane Airways Specialised Register, which contains several databases. We also conducted a search of ClinicalTrials.gov and manufacturers' websites. The most recent searches were conducted on 6 April 2018. Selection criteria: We included randomised controlled trials (RCTs) that recruited people aged 35 years or older with a diagnosis of COPD and a baseline forced expiratory volume in one second (FEV1) of less than 80% of predicted. We included studies of at least 12 weeks' duration including at least two active comparators from one of the four inhaler groups. Data collection and analysis: We conducted NMAs using a Bayesian Markov chain Monte Carlo method. We considered a study as high risk if recruited participants had at least one COPD exacerbation within the 12 months before study entry and as low risk otherwise. Primary outcomes were COPD exacerbations (moderate to severe and severe), and secondary outcomes included symptom and quality-of-life scores, safety outcomes, and lung function. We collected data only for active comparators and did not consider placebo was not considered. We assumed a class/group effect when a fixed-class model fitted well. Otherwise we used a random-class model to assess intraclass/group differences. We supplemented the NMAs with pairwise meta-analyses. Main results: We included a total of 101,311 participants from 99 studies (26 studies with 32,265 participants in the high-risk population and 73 studies with 69,046 participants in the low-risk population) in our systematic review. The median duration of studies was 52 weeks in the high-risk population and 26 weeks in the low-risk population (range 12 to 156 for both populations). We considered the quality of included studies generally to be good. The NMAs suggested that the LABA/LAMA combination was the highest ranked treatment group to reduce COPD exacerbations followed by LAMA in the both populations. There is evidence that the LABA/LAMA combination decreases moderate to severe exacerbations compared to LABA/ICS combination, LAMA, and LABA in the high-risk population (network hazard ratios (HRs) 0.86 (95% credible interval (CrI) 0.76 to 0.99), 0.87 (95% CrI 0.78 to 0.99), and 0.70 (95% CrI 0.61 to 0.8) respectively), and that LAMA decreases moderate to severe exacerbations compared to LABA in the high- and low-risk populations (network HR 0.80 (95% CrI 0.71 to 0.88) and 0.87 (95% CrI 0.78 to 0.97), respectively). There is evidence that the LABA/LAMA combination reduces severe exacerbations compared to LABA/ICS combination and LABA in the high-risk population (network HR 0.78 (95% CrI 0.64 to 0.93) and 0.64 (95% CrI 0.51 to 0.81), respectively). There was a general trend towards a greater improvement in symptom and quality-of-life scores with the combination therapies compared to monotherapies, and the combination therapies were generally ranked higher than monotherapies. The LABA/ICS combination was the lowest ranked in pneumonia serious adverse events (SAEs) in both populations. There is evidence that the LABA/ICS combination increases the odds of pneumonia compared to LAMA/LABA combination, LAMA and LABA (network ORs: 1.69 (95% CrI 1.20 to 2.44), 1.78 (95% CrI 1.33 to 2.39), and 1.50 (95% CrI 1.17 to 1.92) in the high-risk population and network or pairwise OR: 2.33 (95% CI 1.03 to 5.26), 2.02 (95% CrI 1.16 to 3.72), and 1.93 (95% CrI 1.29 to 3.22) in the low-risk population respectively). There were significant overlaps in the rank statistics in the other safety outcomes including mortality, total, COPD, and cardiac SAEs, and dropouts due to adverse events. None of the differences in lung function met a minimal clinically important difference criterion except for LABA/LAMA combination versus LABA in the high-risk population (network mean difference 0.13 L (95% CrI 0.10 to 0.15). The results of pairwise meta-analyses generally agreed with those of the NMAs. There is no evidence to suggest intraclass/group differences except for lung function at 12 months in the high-risk population. Authors' conclusions: The LABA/LAMA combination was the highest ranked treatment group to reduce COPD exacerbations although there was some uncertainty in the results. LAMA containing inhalers may have an advantage over those without a LAMA for preventing COPD exacerbations based on the rank statistics. Combination therapies appear more effective than monotherapies for improving symptom and quality-of-life scores. ICS-containing inhalers are associated with an increased risk of pneumonia. Our most comprehensive review including intraclass/group comparisons, free combination therapies, 99 studies, and 20 outcomes for each high- and low-risk population summarises the current literature and could help with updating existing COPD guidelines
Assessing performance of the Healthcare Access and Quality Index, overall and by select age groups, for 204 countries and territories, 1990-2019: a systematic analysis from the Global Burden of Disease Study 2019
Background: Health-care needs change throughout the life course. It is thus crucial to assess whether health systems provide access to quality health care for all ages. Drawing from the Global Burden of Diseases, Injuries, and Risk Factors Study 2019 (GBD 2019), we measured the Healthcare Access and Quality (HAQ) Index overall and for select age groups in 204 locations from 1990 to 2019. Methods: We distinguished the overall HAQ Index (ages 0–74 years) from scores for select age groups: the young (ages 0–14 years), working (ages 15–64 years), and post-working (ages 65–74 years) groups. For GBD 2019, HAQ Index construction methods were updated to use the arithmetic mean of scaled mortality-to-incidence ratios (MIRs) and risk-standardised death rates (RSDRs) for 32 causes of death that should not occur in the presence of timely, quality health care. Across locations and years, MIRs and RSDRs were scaled from 0 (worst) to 100 (best) separately, putting the HAQ Index on a different relative scale for each age group. We estimated absolute convergence for each group on the basis of whether the HAQ Index grew faster in absolute terms between 1990 and 2019 in countries with lower 1990 HAQ Index scores than countries with higher 1990 HAQ Index scores and by Socio-demographic Index (SDI) quintile. SDI is a summary metric of overall development. Findings: Between 1990 and 2019, the HAQ Index increased overall (by 19·6 points, 95% uncertainty interval 17·9–21·3), as well as among the young (22·5, 19·9–24·7), working (17·2, 15·2–19·1), and post-working (15·1, 13·2–17·0) age groups. Large differences in HAQ Index scores were present across SDI levels in 2019, with the overall index ranging from 30·7 (28·6–33·0) on average in low-SDI countries to 83·4 (82·4–84·3) on average in high-SDI countries. Similarly large ranges between low-SDI and high-SDI countries, respectively, were estimated in the HAQ Index for the young (40·4–89·0), working (33·8–82·8), and post-working (30·4–79·1) groups. Absolute convergence in HAQ Index was estimated in the young group only. In contrast, divergence was estimated among the working and post-working groups, driven by slow progress in low-SDI countries. Interpretation: Although major gaps remain across levels of social and economic development, convergence in the young group is an encouraging sign of reduced disparities in health-care access and quality. However, divergence in the working and post-working groups indicates that health-care access and quality is lagging at lower levels of social and economic development. To meet the needs of ageing populations, health systems need to improve health-care access and quality for working-age adults and older populations while continuing to realise gains among the young. Funding: Bill & Melinda Gates Foundation
Tracking development assistance for health and for COVID-19 : a review of development assistance, government, out-of-pocket, and other private spending on health for 204 countries and territories, 1990-2050
Background The rapid spread of COVID-19 renewed the focus on how health systems across the globe are financed, especially during public health emergencies. Development assistance is an important source of health financing in many low-income countries, yet little is known about how much of this funding was disbursed for COVID-19. We aimed to put development assistance for health for COVID-19 in the context of broader trends in global health financing, and to estimate total health spending from 1995 to 2050 and development assistance for COVID-19 in 2020. Methods We estimated domestic health spending and development assistance for health to generate total health-sector spending estimates for 204 countries and territories. We leveraged data from the WHO Global Health Expenditure Database to produce estimates of domestic health spending. To generate estimates for development assistance for health, we relied on project-level disbursement data from the major international development agencies' online databases and annual financial statements and reports for information on income sources. To adjust our estimates for 2020 to include disbursements related to COVID-19, we extracted project data on commitments and disbursements from a broader set of databases (because not all of the data sources used to estimate the historical series extend to 2020), including the UN Office of Humanitarian Assistance Financial Tracking Service and the International Aid Transparency Initiative. We reported all the historic and future spending estimates in inflation-adjusted 2020 US per capita, purchasing-power parity-adjusted US8. 8 trillion (95% uncertainty interval [UI] 8.7-8.8) or 40.4 billion (0.5%, 95% UI 0.5-0.5) was development assistance for health provided to low-income and middle-income countries, which made up 24.6% (UI 24.0-25.1) of total spending in low-income countries. We estimate that 13.7 billion was targeted toward the COVID-19 health response. 1.4 billion was repurposed from existing health projects. 2.4 billion (17.9%) was for supply chain and logistics. Only 1519 (1448-1591) per person in 2050, although spending across countries is expected to remain varied. Interpretation Global health spending is expected to continue to grow, but remain unequally distributed between countries. We estimate that development organisations substantially increased the amount of development assistance for health provided in 2020. Continued efforts are needed to raise sufficient resources to mitigate the pandemic for the most vulnerable, and to help curtail the pandemic for all. Copyright (C) 2021 The Author(s). Published by Elsevier Ltd.Peer reviewe
Mapping development and health effects of cooking with solid fuels in low-income and middle-income countries, 2000–18: a geospatial modelling study
Background: More than 3 billion people do not have access to clean energy and primarily use solid fuels to cook. Use of solid fuels generates household air pollution, which was associated with more than 2 million deaths in 2019. Although local patterns in cooking vary systematically, subnational trends in use of solid fuels have yet to be comprehensively analysed. We estimated the prevalence of solid-fuel use with high spatial resolution to explore subnational inequalities, assess local progress, and assess the effects on health in low-income and middle-income countries (LMICs) without universal access to clean fuels. Methods: We did a geospatial modelling study to map the prevalence of solid-fuel use for cooking at a 5 km × 5 km resolution in 98 LMICs based on 2·1 million household observations of the primary cooking fuel used from 663 population-based household surveys over the years 2000 to 2018. We use observed temporal patterns to forecast household air pollution in 2030 and to assess the probability of attaining the Sustainable Development Goal (SDG) target indicator for clean cooking. We aligned our estimates of household air pollution to geospatial estimates of ambient air pollution to establish the risk transition occurring in LMICs. Finally, we quantified the effect of residual primary solid-fuel use for cooking on child health by doing a counterfactual risk assessment to estimate the proportion of deaths from lower respiratory tract infections in children younger than 5 years that could be associated with household air pollution. Findings: Although primary reliance on solid-fuel use for cooking has declined globally, it remains widespread. 593 million people live in districts where the prevalence of solid-fuel use for cooking exceeds 95%. 66% of people in LMICs live in districts that are not on track to meet the SDG target for universal access to clean energy by 2030. Household air pollution continues to be a major contributor to particulate exposure in LMICs, and rising ambient air pollution is undermining potential gains from reductions in the prevalence of solid-fuel use for cooking in many countries. We estimated that, in 2018, 205 000 (95% uncertainty interval 147 000–257 000) children younger than 5 years died from lower respiratory tract infections that could be attributed to household air pollution. Interpretation: Efforts to accelerate the adoption of clean cooking fuels need to be substantially increased and recalibrated to account for subnational inequalities, because there are substantial opportunities to improve air quality and avert child mortality associated with household air pollution. Funding: Bill & Melinda Gates Foundation
Mapping development and health effects of cooking with solid fuels in low-income and middle-income countries, 2000-18 : a geospatial modelling study
Background More than 3 billion people do not have access to clean energy and primarily use solid fuels to cook. Use of solid fuels generates household air pollution, which was associated with more than 2 million deaths in 2019. Although local patterns in cooking vary systematically, subnational trends in use of solid fuels have yet to be comprehensively analysed. We estimated the prevalence of solid-fuel use with high spatial resolution to explore subnational inequalities, assess local progress, and assess the effects on health in low-income and middle-income countries (LMICs) without universal access to clean fuels.Methods We did a geospatial modelling study to map the prevalence of solid-fuel use for cooking at a 5 km x 5 km resolution in 98 LMICs based on 2.1 million household observations of the primary cooking fuel used from 663 population-based household surveys over the years 2000 to 2018. We use observed temporal patterns to forecast household air pollution in 2030 and to assess the probability of attaining the Sustainable Development Goal (SDG) target indicator for clean cooking. We aligned our estimates of household air pollution to geospatial estimates of ambient air pollution to establish the risk transition occurring in LMICs. Finally, we quantified the effect of residual primary solid-fuel use for cooking on child health by doing a counterfactual risk assessment to estimate the proportion of deaths from lower respiratory tract infections in children younger than 5 years that could be associated with household air pollution.Findings Although primary reliance on solid-fuel use for cooking has declined globally, it remains widespread. 593 million people live in districts where the prevalence of solid-fuel use for cooking exceeds 95%. 66% of people in LMICs live in districts that are not on track to meet the SDG target for universal access to clean energy by 2030. Household air pollution continues to be a major contributor to particulate exposure in LMICs, and rising ambient air pollution is undermining potential gains from reductions in the prevalence of solid-fuel use for cooking in many countries. We estimated that, in 2018, 205000 (95% uncertainty interval 147000-257000) children younger than 5 years died from lower respiratory tract infections that could be attributed to household air pollution.Interpretation Efforts to accelerate the adoption of clean cooking fuels need to be substantially increased and recalibrated to account for subnational inequalities, because there are substantial opportunities to improve air quality and avert child mortality associated with household air pollution. Copyright (C) 2022 The Author(s). Published by Elsevier Ltd.Peer reviewe
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