2-Approximation for Prize-Collecting Steiner Forest

Approximation algorithms for the prize-collecting Steiner forest problem (PCSF) have been a subject of research for over three decades, starting with the seminal works of Agrawal, Klein, and Ravi and Goemans and Williamson on Steiner forest and prize-collecting problems. In this paper, we propose and analyze a natural deterministic algorithm for PCSF that achieves a $2$-approximate solution in polynomial time. This represents a significant improvement compared to the previously best known algorithm with a $2.54$-approximation factor developed by Hajiaghayi and Jain in 2006. Furthermore, K{\"{o}}nemann, Olver, Pashkovich, Ravi, Swamy, and Vygen have established an integrality gap of at least $9/4$ for the natural LP relaxation for PCSF. However, we surpass this gap through the utilization of a combinatorial algorithm and a novel analysis technique. Since $2$ is the best known approximation guarantee for Steiner forest problem, which is a special case of PCSF, our result matches this factor and closes the gap between the Steiner forest problem and its generalized version, PCSF

Comparative study of various smeared crack models for concrete dams

U radu je istražen nelinearni seizmički odgovor betonske gravitacijske brane. Za usporednu analizu profila pukotina i odgovore brane primijenjena je nelinearna mehanika loma triju modela razmazanih pukotina. Primjenom metode konačnih elemenata, dinamička jednadžba je riješena modificiranom Newton-Raphsonovom metodom i Bosakovim algoritmom vremenske integracije. Razmotreni su utjecaji modela razmazanih pukotina na seizmički odgovor brane Pine Flat, a rezultati su pokazali da postoje razlike u glavnim naprezanjima, pomacima krune brane, broju i obliku pukotina.The nonlinear seismic response of concrete gravity dams is investigated in the paper. Nonlinear fracture mechanics based on three smeared crack models is used for comparative study of the cracking profile and dam response. Using the finite element method, the dynamic equation is solved by means of the modified Newton-Raphson method and Bosak’s time integration algorithm. The effects of crack models on seismic response of Pine Flat Dam are discussed. The results reveal some differences in principal stress, dam crest displacement, and in the number and shape of cracks

Association of NFKB1 gene polymorphism (rs28362491) with cardiometabolic risk factor in patients undergoing coronary angiography

Introduction: Genetic and environmental factors are involved in the pathogenesis of cardiovascular diseases (CVDs). The aim of the study was to investigate between the genotype of the NFKB1 gene and the cardiometabolic risk factor in patients undergoing coronary angiography. Methods: This cross-sectional study was conducted on 462 adults (male and women) aged between 35 and 75 years who referred to Afshar Hospital for coronary angiography in 2021- 2022. The polymerase chain reaction restriction fragment length polymorphism method was used to detect the genotype of rs28362491. Biochemical parameters were measured using commercial kits. Gensini and Syntax scores were calculated using the angiography result to assess the extent of coronary artery stenosis. We used multivariate logistic regression analysis to examine the relationship between genotype variants and cardiometabolic risk factors. Results: There was no association between variant genotypes and abnormally levels of serum alanine aminotransferase (ALT) (P value=0.51), aspartate aminotransferase (AST) (P value=0.99), triglyceride (TG) (P value=0.48), total cholesterol (P value=0.79), low density lipoprotein-cholestero (LDL-C) (P value=0.31), high-density lipoprotein-cholesterol (HDL-C) (P value=0.53), fast blood sugar (FBS) (P value=0.39), systolic blood pressure (P value=0.14), diastolic blood pressure (P value=0.64), Gensini score (P value=0.48) and syntax score (P value=0.74) in the crude model even after adjustment for confounding factors. Conclusion: We found no association between the ATTG polymorphism and cardiometabolic risk factors in patients who had coronary angiography. Further investigations are needed to assess the association between variants of 28362491 and cardiometabolic markers

Nonlinear analysis of concrete gravity dams under normal fault motion

The importance of the seismic behavior of concrete gravity dams in their safety evaluation and stability is inevitable. Many factors affect the prediction of the behavior of concrete dams such as dam-foundation-reservoir interaction, dam and foundation cracking and also displacement due to fault movement that could causes nonlinear behavior. The aim of this study is nonlinear analysis of concrete gravity dams, including displacement caused by normal fault movement in the dam foundation. For this purpose, dam-foundation-reservoir system is modeled using Lagrangian method and analysis of system is done by finite element method. The coordinate smeared crack model based on the nonlinear fracture mechanics is used for crack modeling in the dam body and foundation. Using two separate method including split node technique and contact element, the fault movement are modeled and the position and angle of fault has been studied. To verify the results, dam crest displacement and crack profile in the body of a concrete gravity dam is presented as an example. The results show that low fault movement causes the cracks in the dam body and could be jeopardizes the stability and safety of concrete dam

Nickel Removal from Aqueous Environments Using Carbon Nanotubes

Nickel is one of the heavy metals in the surface water that its Harmful effects can include bone and lung cancers, cyanosis, chronic headaches, dizziness, and chest pain and body weakness. This study has been performed to determine the efficiency of reducing nickel from aqueous environments by using carbon nanotubes. Experiments were performed in batch reactor and changing effective factors such as pH, time and concentration of carbon nanotubes. Removal efficiency was investigated using a Friedman statistical test, software SPSS-16.The highest removal efficiency was 82.5% at a concentration of 100 mg/L of carbon nanotubes, pH = 10, retention time of 10 min and nickel concentrations of 40 mg/L. The results showed that carbon nanotubes have a high ability to absorb high concentrations of nickel in the aquatic environment

Frequency of Seroma and Associated Factors after Inguinal Hernioplasty: A Brief Report

Background and purpose: Seroma formation is one of the most common complications of hernioplasty surgery. Identifying the factors associated with seroma is useful to prevent this complication. The present study aimed at investigating the frequency of seroma and related demographic and clinical factors after inguinal hernioplasty. Materials and methods: This cross-sectional study was performed in 130 patients with primary inguinal hernia who underwent inguinal hernioplasty using mesh in Rasht Poursina Hospital, 2019. Any accumulation of fluid at/around the surgical site that caused obvious bulging and discomfort, pain, and heaviness that required needle aspiration was considered to be seroma. The frequency of seroma was assessed at 24 hours, one week, and one month after the surgery. Demographic and clinical variables were assessed by oral questioning and reviewing the medical files. Statistical analysis was performed in SPSS V20. Results: Seroma was seen in 5 (3.8%) (95% CI: 1%-7%), 8 (6.2%) (95% CI: 2%-10%), and 7 patients (5.4%) (95% CI: 1.3%-8.7%) at 24 hours, one week, and one month after the surgery, respectively. Conclusion: Similar descriptive studies including larger sample size and experimental studies are needed to accurately investigate the relationship between demographic and clinical factors and the incidence of seroma after hernioplasty surgery. Also, assessing the effectiveness of various surgical techniques is of great help in preventing this complication

The effect of concentration on gas sensor model based on graphene nanoribbon

Graphene nanoribbon (GNR), a superior material with two-dimensional structure and monolayer honeycomb of carbon, is noteworthy and important in all fields' mainly electronic, chemistry, biology, physics and nanotechnology. Recently, observing about sensors demonstrates that for better accuracy, faster response time and enlarged sensitivity, it needs to be improved. Nowadays, carbon-based equipments as an exclusive substance are remarkable in the sensing technology. High conductivity as unique properties caused that graphene can be used in biological applications. Gas sensor based on graphene can be supposed to have great sensitivity for gas molecules detection. In this study, graphene-based carbon dioxide sensor analytically is modeled. In addition, new methods of gas sensor model based on the gradient of GNR conductance are provided. Also, a field effect transistor-based structure as a modeling platform is suggested. Ultimately, optimum model is evaluated by comparison study between analytical model and experimental performance

The diagnosis of microorganism involved in infective endocarditis (IE) by polymerase chain reaction (PCR) and real-time PCR: A systematic review

Broad-range bacterial rDNA polymerase chain reaction (PCR) followed by sequencing may be identified as the etiology of infective endocarditis (IE) from surgically removed valve tissue; therefore, we reviewed the value of molecular testing in identifying organisms' DNA in the studies conducted until 2016. We searched Google Scholar, Scopus, ScienceDirect, Cochrane, PubMed, and Medline electronic databases without any time limitations up to December 2016 for English studies reporting microorganisms involved in infective endocarditis microbiology using PCR and real-time PCR. Most studies were prospective. Eleven out of 12 studies used valve tissue samples and blood cultures while only 1 study used whole blood. Also, 10 studies used the molecular method of PCR while 2 studies used real-time PCR. Most studies used 16S rDNA gene as the target gene. The bacteria were identified as the most common microorganisms involved in infective endocarditis. Streptococcus spp. and Staphylococcus spp. were, by far, the most predominant bacteria detected. In all studies, PCR and real-time PCR identified more pathogens than blood and tissue cultures; moreover, the sensitivity and specificity of PCR and real-time PCR were more than cultures in most of the studies. The highest sensitivity and specificity were 96% and 100%, respectively. The gram positive bacteria were the most frequent cause of infective endocarditis. The molecular methods enjoy a greater sensitivity compared to the conventional blood culture methods; yet, they are applicable only to the valve tissue of the patients undergoing cardiac valve surgery

Interaction of dietary patterns with rs28362491 on severity of coronary artery stenosis in patients undergoing coronary angiography

Abstract Coronary artery disease (CAD) is one of the most important cardiovascular diseases. Lifestyle and genetic factors play important roles in the development of CAD. The aim of the study is to examine the interaction of dietary patterns and genes on the likelihood of abnormal lipid profile and coronary artery stenosis in Iranians undergoing coronary angiography. This cross-sectional study was performed on 440 patients who underwent coronary angiography. The factor analysis method was used to extract dietary patterns. Commercial kits have been used to assess biochemical parameters. The detection of the rs28362491 genotype was carried out by the method of restriction fragment length polymorphism. Traditional (TDP) and western dietary pattern (WDP) were extracted. We observed an interaction of adherence to TDP and rs28362491 on the odds of having a high Gensini score. These interactions indicated that higher adherence to TDP was associated with higher odds of having a high Gensini score for patients with DD genotype than for those with II genotype. (OR 2.33, 95%CI 1.00–5.44; P = 0.05). These interactions remained statistically significant even after confounder variables. We observed an interaction between higher adherence to TDP and rs28362491 variants on the odds of high low-density lipoprotein cholesterol levels (P = 0.04) in the unadjusted model. We found a significant interaction of this polymorphism and higher adherence to WDP on the odds of having a high Gensini score in the unadjusted model (P = 0.04). This study provides a basis for future research on NF-KB1 gene and diet interaction. More large-scale longitudinal studies are needed to validate these findings