80 research outputs found
Experimental investigation on energy absorption of auxetic structures
The human being has always been looking for optimal use of his surrounding materials and over the years, has managed to invent various structures with special properties. Lattice structures are widely used in various applications due to their lower weight and desirable compressive strength. An example of these structures is the honeycomb that is very popular and many studies have been done about it. A new type of lattice structures is auxetic structure that has negative Poisson’s ratio due to its geometry. This characteristic has caused auxetic structures to have unique properties such as high shear strength, indentation resistance and energy absorption. Investigation of energy absorption of auxetic structures is a subject that has not been studied in researches. In this study, the ability of some auxetic structure for absorbing energy is investigated at quasi-static and low velocity impact transverse loading. Specimens with three types of geometries (re-entrant, arrowhead and anti-tetra chiral) are fabricated using additive manufacturing method (3D printing). Discussion about energy absorption and failure mechanisms of all three structures were carried out and compared in both types of loading
Frequency Assessment of OXA-10 and PER beta-Lactamase Genes and Determination of Minimum Inhibitory Concentration in Klebsiella Strains Isolated from Urinary Tract Infections
Background: Klebsiella is one of the Enterobacteriaceae family that causes infections such as pneumonia, urinary tract infections (UTI), and meningitis. Klebsiella strains are capable of producing enzymes that can degrade the third-generation of cephalosporins known as broad-spectrum beta-lactamase enzymes. The resistance of Klebsiella strains to beta-lactam antibiotics is related to the presence of beta-lactamase genes.
Methods: In this study, 90 isolates of Klebsiella were isolated from two inpatient and outpatient groups, each of them was 45 isolates, which were collected from patients with urinary tract infection in educational hospitals of Shahrekord. The isolates were identified using phenotypic agar diffusion, disc phenotypic confirmation tests, and E-test of extended-spectrum beta-lactamase (ESBL). The PCR molecular method was used to diagnose and determine the strains containing broad-spectrum beta-lactamases.
Results: Thirty (66%) inpatients and 8 (17.8%) outpatients had broad-spectrum beta-lactamase enzymes. The frequency of beta-lactamase OXA-10 genes and PER in inpatients were 90% and 33%, respectively and also in outpatients were 50% and 12.5%, respectively.
Conclusions: This study showed that the prevalence of isolated Klebsiella producing broad-spectrum beta-lactamases is higher in in-patients in comparison to outpatients. Therefore, the rapid and accurate identification of bacteria and their resistance genes in clinical microbiology labs are highly recommended.
Keywords
Author Keywords:Klebsiella; Minimum Inhibitory Concentration; Extended Spectrum beta-Lactamases; OXA-10; PER Gen
Association between sleep duration and hypertension incidence: Systematic review and meta-analysis of cohort studies
Aim: Sleep duration has been suggested to be associated with hypertension (HTN). However, evidence of the nature of the relationship and its direction has been inconsistent. Therefore, we performed a meta-analysis to assess the relationship between sleep duration and risk of HTN incidence, and to distinguish more susceptible populations. Methods: PubMed, Embase, Scopus, Web of Science, and ProQuest were searched from January 2000 to May 2023 for cohort studies comparing short and long sleep durations with 7–8 hours of sleep for the risk of HTN incidence. Random-effect model (the DerSimonian-Laird method) was applied to pool risk ratios (RR) and 95% confidence interval (CI). Results: We included sixteen studies ranging from 2.4 to 18 years of follow-up duration evaluating HTN incidence in 1,044,035 people. Short sleep duration was significantly associated with a higher risk of developing HTN (HR: 1.07, 95% CI: 1.06–1.09). The association was stronger when the sleep duration was less than 5 hours (HR: 1.11, 95% CI: 1.08–1.14). In contrast to males, females (HR: 1.07, 95% CI: 1.04–1.09) were more vulnerable to developing HTN due to short sleep duration. No significant difference between different follow-up durations and age subgroups was observed. Long sleep duration was not associated with an increased incidence of HTN. Conclusion: Short sleep duration was associated with higher risk of HTN incidence, however, there was no association between long sleep duration and incidence of HTN. These findings highlight the importance of implementing target-specific preventive and interventional strategies for vulnerable populations with short sleep duration to reduce the risk of HTN
Higher Glycemic Index and Load Could Increase Risk of Dyslipidemia
Background: To quantify carbohydrates, various indicators such as glycemic load (GL) and glycemic index (GI) were introduced. In order to address the effect of dietary carbohydrate content on lipid profile, we investigated the relationship between dietary GI and GL with lipid profile in adults living in Shiraz, Iran.Methods: In a cross-sectional study, 236 participants aged between 20 and 50 years were selected using cluster random sampling in Shiraz, Iran. For assessing the food intake, a 168-item food frequency questionnaire (FFQ) was utilized. Dietary GI and GL were calculated based on food items intake.Results: Higher GI was associated with increased odds ratio (OR) of lowdensity lipoprotein-cholesterol (LDL-C, OR: 2.51; p-trend=0.008), nonhigh-density lipoprotein-cholesterol (HDL, OR: 2.34; p-trend=0.01) and LDL to HDL ratio (OR: 2.13; p-trend=0.02) in crude model. In adjusted model, direct association was observed between GI and total cholesterol (TC, OR: 2.40; p-trend=0.01), LDL-C (OR: 2.50; p-trend=0.01) and non-HDL-C (OR: 2.48; p-trend=0.01). Association was noted between higher GL with TC (OR: 2.50; p-trend=0.01), LDL-C (OR: 2.22; p-trend=0.02), non-HDL-C (OR: 2.49; p-trend=0.005) and LDL-C to HDL-C ratio (OR: 2.29; p-trend=0.01) in crude model. After adjusting for potential cofounder, association remained for TC (OR: 3.97; p-trend=0.01), LDL-C (OR: 4.39; p-trend=0.005) and non-HDL-C (OR: 3.72; p-trend=0.008).Conclusion: Dietary GI and GL may have an association with higher odds of abnormal lipid profile. It seems that a diet with a low GI and GL (which full of whole grains, fruits, vegetables, nuts and legumes) can play an effective role in favorable lipid profile
Prevalence of Cannabis Lifetime Use in Iranian High School and College Students: A Systematic Review, Meta-Analyses,and Meta-Regression
Cannabis is the most widely used substance in the world. This study aimed to estimate the prevalence of cannabis lifetime use (CLU) in high school and college students of Iran and also to determine factors related to changes in prevalence. A systematic review of literature on cannabis use in Iran was conducted according to MOOSE guideline. Domestic scientific databases, PubMed/Medline, ISI Web of Knowledge, and Google Scholar, relevant reference lists, and relevant journals were searched up to April, 2014. Prevalences were calculated using the variance stabilizing double arcsine transformation and confidence intervals (CIs) estimated using the Wilson method. Heterogeneity was assessed by Cochran's Q statistic and I-2 index and causes of heterogeneity were evaluated using meta-regression model. In electronic database search, 4,000 citations were retrieved, producing a total of 33 studies. CLU was reported with a random effects pooled prevalence of 4.0 (95 CI = 3.0 to 5.0). In subgroups of high school and college students, prevalences were 5.0 (95 CI = 3.0 to -7.0) and 2.0 (95 CI = 2.0 to -3.0), respectively. Meta-regression model indicated that prevalence is higher in college students (beta = 0.089, p < .001), male gender (beta = 0.017, p < .001), and is lower in studies with sampling versus census studies (beta = -0.096, p < .001). This study reported that prevalence of CLU in Iranian students are lower than industrialized countries. In addition, gender, level of education, and methods of sampling are highly associated with changes in the prevalence of CLU across provinces
The Effect of Aromatherapy with Lavender on Pain of Needle Insertion and Severity of Restless Legs Syndrome in Hemodialysis Patients; a Systematic Review and Meta-analysis
Introduction: Pain experienced during the insertion of a catheter into the arteriovenous fistula (AVF) and restless legs syndrome (RLS) are prevalent issues among Hemodialysis (HD) patients. The primary objective of this systematic review and meta-analysis was to consolidate the findings from randomized clinical trial (RCT) studies examining the impact of aromatherapy with lavender on the pain associated with AVF catheter insertion and RLS in HD patients.
Methods: A systematic search was conducted on PubMed, Web of Science, Scopus, Cochrane, Embase, ClinicalTrials.gov, and Google Scholar search engine from inception to August 1, 2022, using keywords extracted from Medical Subject Headings, such as “Aromatherapy”, “Lavender”, “Arteriovenous fistula”, “Pain”, “Restless legs syndrome”, and “Hemodialysis”.
Results: Finally, eleven articles were included in this systematic review and meta-analysis. The results showed that aromatherapy reduced the average pain of catheter insertion in AVF compared to the control group (Standard Mean Difference: -1.60, 95% Confidence Interval: -2.32 to -0.87, Z=4.32, I2:90.3%, P<0.001). Also, aromatherapy massage reduced the average severity of RLS compared to the control group, which was statistically significant (Weighted Mean Difference: -13.21, 95% Confidence Interval: -17.50 to -8.91, Z=6.03, I2:93.0%, P<0.001). Also, the subgroup analysis showed that lavender in the intervention group significantly decreased the pain intensity compared to the "no intervention" group (P<0.001), yet it was not significant compared to the placebo group (P=0.12).
Conclusion: In summary, the findings indicate a notable reduction in catheter insertion pain in AVF and relief from RLS among HD patients through the use of lavender essential oil. As a result, future research is encouraged to include a comparison of lavender's effects with those of a placebo group
Mapping 123 million neonatal, infant and child deaths between 2000 and 2017
Since 2000, many countries have achieved considerable success in improving child survival, but localized progress remains unclear. To inform efforts towards United Nations Sustainable Development Goal 3.2—to end preventable child deaths by 2030—we need consistently estimated data at the subnational level regarding child mortality rates and trends. Here we quantified, for the period 2000–2017, the subnational variation in mortality rates and number of deaths of neonates, infants and children under 5 years of age within 99 low- and middle-income countries using a geostatistical survival model. We estimated that 32% of children under 5 in these countries lived in districts that had attained rates of 25 or fewer child deaths per 1,000 live births by 2017, and that 58% of child deaths between 2000 and 2017 in these countries could have been averted in the absence of geographical inequality. This study enables the identification of high-mortality clusters, patterns of progress and geographical inequalities to inform appropriate investments and implementations that will help to improve the health of all populations
Global, regional, and national cancer incidence, mortality, years of life lost, years lived with disability, and disability-Adjusted life-years for 29 cancer groups, 1990 to 2017 : A systematic analysis for the global burden of disease study
Importance: Cancer and other noncommunicable diseases (NCDs) are now widely recognized as a threat to global development. The latest United Nations high-level meeting on NCDs reaffirmed this observation and also highlighted the slow progress in meeting the 2011 Political Declaration on the Prevention and Control of Noncommunicable Diseases and the third Sustainable Development Goal. Lack of situational analyses, priority setting, and budgeting have been identified as major obstacles in achieving these goals. All of these have in common that they require information on the local cancer epidemiology. The Global Burden of Disease (GBD) study is uniquely poised to provide these crucial data. Objective: To describe cancer burden for 29 cancer groups in 195 countries from 1990 through 2017 to provide data needed for cancer control planning. Evidence Review: We used the GBD study estimation methods to describe cancer incidence, mortality, years lived with disability, years of life lost, and disability-Adjusted life-years (DALYs). Results are presented at the national level as well as by Socio-demographic Index (SDI), a composite indicator of income, educational attainment, and total fertility rate. We also analyzed the influence of the epidemiological vs the demographic transition on cancer incidence. Findings: In 2017, there were 24.5 million incident cancer cases worldwide (16.8 million without nonmelanoma skin cancer [NMSC]) and 9.6 million cancer deaths. The majority of cancer DALYs came from years of life lost (97%), and only 3% came from years lived with disability. The odds of developing cancer were the lowest in the low SDI quintile (1 in 7) and the highest in the high SDI quintile (1 in 2) for both sexes. In 2017, the most common incident cancers in men were NMSC (4.3 million incident cases); tracheal, bronchus, and lung (TBL) cancer (1.5 million incident cases); and prostate cancer (1.3 million incident cases). The most common causes of cancer deaths and DALYs for men were TBL cancer (1.3 million deaths and 28.4 million DALYs), liver cancer (572000 deaths and 15.2 million DALYs), and stomach cancer (542000 deaths and 12.2 million DALYs). For women in 2017, the most common incident cancers were NMSC (3.3 million incident cases), breast cancer (1.9 million incident cases), and colorectal cancer (819000 incident cases). The leading causes of cancer deaths and DALYs for women were breast cancer (601000 deaths and 17.4 million DALYs), TBL cancer (596000 deaths and 12.6 million DALYs), and colorectal cancer (414000 deaths and 8.3 million DALYs). Conclusions and Relevance: The national epidemiological profiles of cancer burden in the GBD study show large heterogeneities, which are a reflection of different exposures to risk factors, economic settings, lifestyles, and access to care and screening. The GBD study can be used by policy makers and other stakeholders to develop and improve national and local cancer control in order to achieve the global targets and improve equity in cancer care. © 2019 American Medical Association. All rights reserved.Peer reviewe
Global injury morbidity and mortality from 1990 to 2017 : results from the Global Burden of Disease Study 2017
Correction:Background Past research in population health trends has shown that injuries form a substantial burden of population health loss. Regular updates to injury burden assessments are critical. We report Global Burden of Disease (GBD) 2017 Study estimates on morbidity and mortality for all injuries. Methods We reviewed results for injuries from the GBD 2017 study. GBD 2017 measured injury-specific mortality and years of life lost (YLLs) using the Cause of Death Ensemble model. To measure non-fatal injuries, GBD 2017 modelled injury-specific incidence and converted this to prevalence and years lived with disability (YLDs). YLLs and YLDs were summed to calculate disability-adjusted life years (DALYs). Findings In 1990, there were 4 260 493 (4 085 700 to 4 396 138) injury deaths, which increased to 4 484 722 (4 332 010 to 4 585 554) deaths in 2017, while age-standardised mortality decreased from 1079 (1073 to 1086) to 738 (730 to 745) per 100 000. In 1990, there were 354 064 302 (95% uncertainty interval: 338 174 876 to 371 610 802) new cases of injury globally, which increased to 520 710 288 (493 430 247 to 547 988 635) new cases in 2017. During this time, age-standardised incidence decreased non-significantly from 6824 (6534 to 7147) to 6763 (6412 to 7118) per 100 000. Between 1990 and 2017, age-standardised DALYs decreased from 4947 (4655 to 5233) per 100 000 to 3267 (3058 to 3505). Interpretation Injuries are an important cause of health loss globally, though mortality has declined between 1990 and 2017. Future research in injury burden should focus on prevention in high-burden populations, improving data collection and ensuring access to medical care.Peer reviewe
Mapping local patterns of childhood overweight and wasting in low- and middle-income countries between 2000 and 2017
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
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