Rheological properties of a dilute suspension of self-propelled particles

With a detail microscopic model for a self-propelled swimmer, we derive the rheological properties of a dilute suspension of such particles at small Peclet numbers. It is shown that, in addition to the Einstein's like contribution to the effective viscosity, that is proportional to the volume fraction of the swimmers, a contribution due to the activity of self-propelled particles influences the viscosity. As a result of the activity of swimmers, the effective viscosity would be a lower (higher) than the viscosity of the suspending medium when the particles are pushers (pullers). Such activity dependent contribution, will also results to a non-Newtonian behavior of the suspension in the form of normal stress differences

Effects of Acetyl-L-Carnitine on Cardiac Arrhythmias and Infarct Size in Ischemic-Reperfused Isolated Rat Heart

This study aimed to examine whether acetyl-L-carnitine (ALC) was able to reduce cardiac arrhythmias and infarct size in the ischemic-reperfused isolated rat heart.Materials and MethodsThe isolated hearts were mounted on a Langendorff apparatus then perfused by a modified Krebs-Henseleit solution during 30 min regional ischemia and 120 min reperfusion (control) or by enriched Krebs solution with 0.375, 0.75, 1.5 and 3 mM of ALC (treatment groups). The ECGs were recorded and analyzed to determine cardiac arrhythmias. The infarct size was determined by using a computerized planimetry package.ResultsDuring ischemia, all used concentrations of ALC decreased number and duration of ventricular tachycardia (VT), total number of ventricular ectopic beats (VEBs) (P<0.01), incidence of total ventricular fibrillation (VF) and the time spent for reversible VF (P<0.05). At the reperfusion phase, duration of VT, incidence of total VF and reversible VF were significantly lowered by ALC (P<0.05). In addition, infarct size significantly was decreased in all treated groups. In the control group, the infarct size was 23±3.1%, however, ALC (0.375, 0.75 and 3 mM) reduced it to 8.7±2.3, 5.3±1.4, and 8±2.9%, respectively (P<0.01). ConclusionConsidering the results, it may be concluded that ALC has protective effects against cardiac ischemia-reperfusion (I/R) injuries by reduction of infarct size and arrhythmias in isolated rat heart. Among the potential cardioprotective mechanisms for ALC, increase in glucose oxidation and resulting reduced lactate production, reduction of toxic fatty acid metabolites and removing free radicals from the myocytes are more relevant

Zero Flow Global Ischemia-Induced Injuries in Rat Heart Are Attenuated by Natural Honey

Purpose: In the present study, effects of preischemic administration of natural honey on cardiac arrhythmias and myocardial infarction size during zero flow global ischemia were investigated in isolated rat heart. Methods:The isolated hearts were subjected to 30 min zero flow global ischemia followed by 120 min reperfusion then perfused by a modified drug free Krebs-Henseleit solution throughout the experiment (control) or the solution containing 0.25, 0.5, 1 and 2% of natural honey for 15 min before induction of global ischemia (treated groups), respectively. Cardiac arrhythmias were determined based on the Lambeth conventions and the infarct size was measured by computerized planimetry. Results: Myocardial infarction size was 55.8±7.8% in the control group, while preischemic perfusion of honey (0.25, 0.5, 1 and 2%) reduced it to 39.3±11, 30.6±5.5 (P<0.01), 17.9±5.6 (P<0.001) and 8.7±1.1% (P<0.001), respectively. A direct linear correlation between honey concentrations and infarction size reduction was observed (R2=0.9948). In addition, total number of ventricular ectopic beats were significantly decreased by all used concentrations of honey (P<0.05) during reperfusion time. Honey (0.25, 0.5 and 1 %) also lowered incidence of irreversible ventricular fibrillation (P<0.05). Moreover, number and duration of ventricular tachycardia were reduced in all honey treated groups. Conclusion: Preischemic administration of natural honey before zero flow global ischemia can protect isolated rat heart against ischemia/reperfusion injuries as reduction of infarction size and arrhythmias. Maybe, antioxidant and free radical scavenging activities of honey, reduction of necrotized tissue and providing energy sources may involve in these cardioprotective effects of honey

Effects of Chronic Oral Administration of Natural Honey on Ischemia/Reperfusion-induced Arrhythmias in Isolated Rat Heart

Objective(s)In this study, effects of chronic administration of oral natural honey against ischemia/reperfusion (I/R)-induced cardiac arrhythmias were investigated in isolated rat heart. Materials and MethodsMale Wistar rats were divided into four groups (n= 10-14 rats in each group) and fed with natural honey (1%, 2% and 4% dissolved in the drinking water) for 45 days except for the control group. After anesthesia, the rats’ hearts were isolated quickly, mounted on a Langendorff apparatus and perfused with a modified Krebs-Henseleit solution during stabilization, 30 min regional ischemia followed by 30 min reperfusion. The ECGs were recorded throughout the experiments to analyze cardiac arrhythmias based on the Lambeth conventions. ResultsIn the ischemic phase, honey (1%) significantly reduced (P<0.05) the number and duration of ventricular tachycardia (VT). Honey (1% and 2%) also significantly decreased number of ventricular ectopic beats (VEBs). In addition, incidence and duration of reversible ventricular fibrillation (Rev VF) were lowered by honey 2% (P<0.05). During reperfusion time, VT incidence was 73% in the control group, however natural honey (1%) decreased it to 22% (P<0.05). Honey also produced significant reduction in the incidences of total VF, Rev VF, duration and number of VT. ConclusionFor the first time, the results of present study demonstrated protective effects of chronic oral honey administration against I/R-induced arrhythmias in isolated rat heart. Antioxidant activity, the existence of energy sources such as glucose and fructose and improvement of some hemodynamic functions might be responsible for these effects

What explains socioeconomic inequalities in dental flossing? Cross-sectional results from the RaNCD cohort study

Introduction: The magnitude of or determinants underlying socioeconomic inequalities in the use of dental floss is poorly understood in Iran. This study aimed to measure and decompose socioeconomic inequalities in dental flossing in Ravansar, Iran. Methods: This cross-sectional study used data of 10002 individuals aged 35-65 years obtained from the Ravansar Non-communicable Disease (RaNCD) cohort study located in Kermanshah province, west of Iran.&nbsp; Socioeconomic status was measured through an asset-based method and principal component analysis was carried out to determine the socioeconomic status (SES). The concentration index and curve were used to measure socioeconomic inequality in dental flossing. Decomposition analysis was also used to determine the main determinants that contribute to inequalities in dental flossing. Findings: Of 10,002 participants, 11.74% were found to use dental floss. The normalized CI for use of dental floss was 0.327 in the entire population, 0.323 in females and 0.329 in males, indicating that the use of dental floss is more concentrated among high-SES individuals. The decomposition analysis indicated that SES (50.58%) and level of education (44.90%) respectively contributed the most to this inequality. Place of residence (10.55%) and age group (2.7%) were the next main contributors, respectively. Conclusion: There are a low prevalence and a relatively high degree of pro-rich socioeconomic-related inequality in dental flossing among Iranian adults. Socioeconomic status, level of education and place of residence contributed the most to the observed inequalities in dental flossing. Policy interventions should consider these factors to reduce inequality in the use of dental floss and increase the prevalence of dental flossing. &nbsp

Measuring and Decomposing Socioeconomic Inequalities in Adult Obesity in Western Iran

Objectives Obesity is a considerable and growing public health concern worldwide. The present study aimed to quantify socioeconomic inequalities in adult obesity in western Iran. Methods A total of 10 086 participants, aged 35-65 years, from the Ravansar Non-communicable Disease Cohort Study (2014-2016) were included in the study to examine socioeconomic inequalities in obesity. We defined obesity as a body mass index ≥30 kg/m2. The concentration index and concentration curve were used to illustrate and measure wealth-related inequality in obesity. Additionally, we decomposed the concentration index to identify factors that explained wealth-related inequality in obesity. Results Overall, the prevalence of obesity in the total sample was 26.7%. The concentration index of obesity was 0.04; indicating that obesity was more concentrated among the rich (p<0.001). Decomposition analysis indicated that wealth, place of residence, and marital status were the main contributors to the observed inequality in obesity. Conclusions Socioeconomic-related inequalities in obesity among adults warrant more attention. Policies should be designed to reduce both the prevalence of obesity and inequalities in obesity by focusing on those with higher socioeconomic status, urban residents, and married individuals

Socioeconomic - related inequalities in overweight and obesity: findings from the PERSIAN cohort study

BackgroundOverweight and obesity are major health concerns worldwide, with adverse health consequences during the life span. This study measured socioeconomic inequality in overweight and obesity among Iranian adults.MethodsData were extracted from 129,257 Iranian adults (aged 35years and older) participated in the Prospective Epidemiologic Research Studies in IrAN (PERSIAN) in 14 provinces of Iran in 2014. Socioeconomic-related inequality in overweight and obesity was estimated using the Concentration Index (C-n). The C-n further decomposed to find factors explaining the variability within the Socioeconomic related inequality in overweight and obesity.ResultsOf the total number of participants, 1.98, 26.82, 40.76 and 30.43% had underweight, normal weight, overweight and obesity respectively. The age-and sex standardized prevalence of obesity was higher in females than males (39.85% vs 18.79%). People with high socioeconomic status (SES) had a 39 and 15% higher chance of being overweight and obese than low SES people, respectively. The positive value of C-n suggested a higher concentration of overweight (0.081, 95% confidence interval [CI]; 0.074-0.087) and obesity (0.027, 95% CI; 0.021-0.034) among groups with high SES. There was a wide variation in socioeconomic-related inequality in overweight and obesity rate across 14 provinces. The decomposition results suggested that SES factor itself explained 66.77 and 89.07% of the observed socioeconomic inequalities in overweight and obesity among Iranian adults respectively. Following SES, province of residence, physical activity, using hookah and smoking were the major contributors to the concentration of overweight and obesity among the rich.ConclusionsOverall, we found that overweight and obesity is concentrated among high SES people in the study population. . Accordingly, it seems that intersectional actions should be taken to control and prevent overweight and obesity among higher socioeconomic groups. Keywords:Socioeconomic Factors; Inequality; Concentration index; overweight and obesity; PERSIAN; Ira