Reliability analysis of bistable composite laminates

Bistable composite laminates are smart composites that have been employed for engineering structures due to their superlative offering of features like ability to change shape and low densities. Because of the embedded geometrical nonlinearity factor, a small variation of input parameters leads to significant changes in the response of the bistable composite laminates. In other words, Uncertainty Quantification (UQ) makes a change in the bistability characteristics. As a result, bistability behavior is extremely reliant on geometrical dimensions and elastic material properties as design parameters. Reliability analysis deals with the quantitative assessment of the occurrence probability due to UQ. In this regard, the reliability and sensitivity analysis of bistable composite plate are investigated through the Monte Carlo Simulation (MCS) and multiple types of uncertain parameters, geometry and material properties, are assumed as random variables. The results indicate bistable composite plates have a high probability to be bistability behavior with the assumed statistical properties. Moreover, the sensitivity reliability analysis illustrates that the thickness and coefficient of thermal expansion have more effect on the bistability behavior in comparison to other input parameters. The results are confirmed by comparing them with those determined by the Finite Element Method (FEM)

Scaling of Clusters and Winding Angle Statistics of Iso-height Lines in two-dimensional KPZ Surface

We investigate the statistics of Iso-height lines of (2+1)-dimensional Kardar-Parisi-Zhang model at different level sets around the mean height in the saturation regime. We find that the exponent describing the distribution of the height-cluster size behaves differently for level cuts above and below the mean height, while the fractal dimensions of the height-clusters and their perimeters remain unchanged. The winding angle statistics also confirms again the conformal invariance of these contour lines in the same universality class of self-avoiding random walks (SAWs).Comment: 5 pages, 5 figure

Predictors of Prehospital Delay in Patients With Acute Myocardial Infarction in Kashan City

Background: The prehospital delay might result in death in patients with acute myocardial infarction (AMI). Objectives: This study aimed to investigate the prehospital delay and its related factors in patients with AMI admitted to Kashan’s Shahid Beheshti Hospital. Patients and Methods: This cross-sectional study was conducted on 117 patients with AMI in the second half of 2013. The interval between the onset of symptoms and arrival at the hospital was noted and in cases of delay, the factors leading to the delay were investigated using a questionnaire. The content validity of the questionnaire was confirmed through content validity method and its internal consistency was confirmed using Cronbach's alpha coefficient. Chi-square test, odds ratio, and logistic regression analysis were used in data analysis. Results: The median delay was 129 minutes (mean ± SD, 240.44 ± 295.30). Overall, 32.5% of patients were admitted within 90 minutes of symptom onset. The long distance between living locations to the hospital was the most common cause of delay to hospital admission (31.7%). Significant associations were observed between the delay time and location of residency (P = 0.00) and type of transportation vehicle (P = 0.003). Multivariate logistic regression analysis showed that the location of residency and type of transportation vehicle could significantly predict the delay time in patients with AMI (P = 0.039 and 0.036, respectively). Conclusions: The delay time from symptom onset to hospital admission was high in patients with AMI. It is necessary to create emergency medical system (EMS) stations in suburbs and train the public on the importance of quick contact with the EMS when the symptoms of an AMI are observed

The Effect of Short Duration Sperm Exposure on Development of Preeclampsia in Primigravid Women

Background: Preeclampsia is one of the most serious complications, and affecting about 3 of pregnancies. The aim of this study was to estimate the impact short duration of exposure to sperm on development of preeclampsia. Methods: The duration of sperm exposure with the biological father (cohabitation without barrier methods) <3,<6 months were evaluated among 120 primigravid women with preeclampsia and 120 women without preeclampsia in a case-control study. Results: The short duration of exposure to sperm was more common in women with preeclampsia compared with controls (29.2 versus 14.2 for <3 months, adjOR 2.6 (95 CI=1.32-5.13) and (45 versus 29.2 for <6 months, adjOR 2.4 (95 CI=1.35-4.32). Regardless of the contraceptive method, short duration of cohabitation was more common in preeclamptic group (14.2 versus 5.8 for <3 months, adjOR 3.38 (95 CI=1.28-8.92) and (29.7 versus 13.3 for <6 months, adjOR 2.64(95 CI=1.24-5.79). Conclusion: It was concluded that short duration of exposure to sperm was more common in women with preeclampsia compared with controls. © Iranian Red Crescent Medical Journal

Hospital acquired diarrhea in a burn center of Tehran

Background and Objectives: Incidence of hospital-acquired diarrhea has increased rapidly and burn patients are at high risk of getting it. Infection with C. difficile is the most common cause of antibiotic associated diarrhea. The aim of this study was to determine the baseline characteristics and clinical presentation of hospital-acquired diarrhea and compare C. difficile and non-C. difficile diarrhea in burn patients treated at a burn center. Materials and Methods: During a 1-year study all patients with hospital-acquired diarrhea at Motahari Burn Hospital, Tehran, Iran enrolled in this study. We compared patients with a stool sample positive for C. difficile toxin or tracing the antigen in patients who were negative for detection of toxin in their stool sample specimens. Results: Diarrhea developed in 37 patients out of 3200 admitted patients with a mean burn size of 34.8 ±20.1. Among them, 8 patients had a positive result for C. difficile. The mean time between antibiotic therapy and occurrence of diarrhea was 9.5 ± 6.2 days. Nine (23.7) patients died in the 7.8± 4.2 days, mostly due to co-morbidities. The mean duration of diarrhea was 3.6 ± 2 days. Twenty two (57.9) patients were treated with oral metronidazol and eleven (28.9) patients were treated with combination of metronidazole and vancomycin, higher rate of combination therapy was seen in Clostridium difficile CDI. Conclusion: Overall, the prevalence of hospital-acquired diarrhea was 120/10,000 and 21 of them caused by infection with C. difficile. Presence of peripheral leukocytosis and colitis were the alarm sign for diagnosis of C. difficile infection. © 2015, Tehran University of Medical Science. All rights reserved

Effect of Ginger on Relieving Nausea and Vomiting in Pregnancy: A Randomized, Placebo-Controlled Trial

Background: Nausea and vomiting are common and unpleasant complications in pregnancy. Although many alternative therapists support the use of ginger for nausea and vomiting of pregnancy, there is currently insufficient clinical evidence to support its use in this condition Objectives: The present study was performed to assess the effectiveness of ginger in the treatment of nausea and vomiting in pregnancy. Patients and Methods: This seven-day clinical trial was performed on 120 eligible pregnant women with symptoms of mild to moderate nausea and vomiting before 16 weeks gestation. They were divided into; ginger, placebo and control groups, by block randomization. Women were asked to record their nausea and vomiting for three days, and then participants received either ginger capsules, or a placebo for four days. No intervention was done with the control group. Data measure was self-recorded symptoms according to the Rhodes Index. Data were analyzed by ANOVA, ANCOVA, Kruskal-Wallis, Chi-square, and Fisher’s exact test, for the quantitative and qualitative variables. Results: There were no statistical differences in the baseline demographics between the three groups apart from age of marriage and wanted or unwanted pregnancy. An ANCOVA test (covariance test) showed significant differences in mean scores after the intervention in the three groups (P < 0.001). Conclusions: Ginger was effective for the relief of mild to moderate nausea and vomiting in pregnant women at less than 16 weeks gestation