Fourth Order Algorithms for Solving the Multivariable Langevin Equation and the Kramers Equation

We develop a fourth order simulation algorithm for solving the stochastic Langevin equation. The method consists of identifying solvable operators in the Fokker-Planck equation, factorizing the evolution operator for small time steps to fourth order and implementing the factorization process numerically. A key contribution of this work is to show how certain double commutators in the factorization process can be simulated in practice. The method is general, applicable to the multivariable case, and systematic, with known procedures for doing fourth order factorizations. The fourth order convergence of the resulting algorithm allowed very large time steps to be used. In simulating the Brownian dynamics of 121 Yukawa particles in two dimensions, the converged result of a first order algorithm can be obtained by using time steps 50 times as large. To further demostrate the versatility of our method, we derive two new classes of fourth order algorithms for solving the simpler Kramers equation without requiring the derivative of the force. The convergence of many fourth order algorithms for solving this equation are compared.Comment: 19 pages, 2 figure

Peace Building in Bosnia and Herzegovina: Effects of Ingroup Identification, Outgroup Trust and Intergroup Forgiveness on Intergroup Contact

The current study examines the effects of ingroup identification, outgroup trust, and intergroup forgiveness on intergroup contact quantity in the diverse cities of Sarajevo and Tuzla in Bosnia and Herzegovina. A total of 455 individuals ranging in age from 14 to 102 self-reported as either Muslim, Roman Catholic, Orthodox Christian, or Other completed a questionnaire. Analyses revealed that ingroup identification was significantly and negatively correlated with intergroup contact quantity; however, ingroup identification was not significantly correlated with outgroup trust or intergroup forgiveness. The comparison between groups revealed significant group differences across all predictor and criterion variables. To confirm whether age or community background had a moderating effect on predicting the relation between ingroup identification, outgroup trust, and intergroup forgiveness on intergroup contact quantity, moderated regression analyses were conducted. Results revealed community background, ingroup identification, and outgroup trust were all significant contributors to the model; however, age and forgiveness were not. Taken as a whole, the entire model accounted for approximately 21% of variability in intergroup contact quantity. The results from the current study reinforce the supposition that the two cities of Sarajevo and Tuzla in Bosnia and Herzegovina cannot move towards reconciliation without first understanding the effect that strong ingroup identification has on mixing with the other diverse groups, and implementing proactive measures to enhance outgroup trust and cross-community outreach. Implementing these measures in the two cities of Sarajevo and Tuzla, along with other areas in Bosnia and Herzegovina, may improve future intergroup relations and move the country closer to reconciliation and peace

Polymerase chain reaction in the identification of periodontopathogens: A reliable and satisfactory method?

Aggregatibacter actinomycetemcomitans is considered one of the bacterial species of etiological importance in periodontitis. The aim of this study was to evaluate the serotype of A. actinomycetemcomitans in the subgingival biofilm in subjects with periodontal health and disease. Pooled samples of subgingival plaque were taken for culture-based identification of microorganisms. Colonies suspected to be A. actinomycetemcomitans were selected for molecular identification using either multiplex or conventional PCR in serotype-specific genotyping and 16S rRNA gene sequencing. In silico analysis showed that most selected colonies belong to the genus Campylobacter, although positive signals for serotypes of A. actinomycetemcomitans were obtained with these samples. Identification of A. actinomycetemcomitans by conventional PCR for 16S rRNA with one species-specific and one universal primer was inconclusive because an almost identical signal with Campylobacter gracilis was obtained. Although PCR-based methods for the identification of A. actinomycetemcomitans are more rapid, sequencing should not be omitted. [Projekat Ministarstva nauke Republike Srbije, br. 41008 and br. 173048

Copper-induced changes of lipid peroxidation and hemato-biochemical parameters in rat blood: Protective role of flavonoids

The effects of subchronic exposure to copper (Cu) on lipid peroxidation, hemato-biochemical parameters, and the possible protective role of flavonoids Quercetin and (-)-Epicatechin were studied. Male Wistar albino rats were treated with Cu (560 mg/L, p.o. as CuCl2·2H2O for 5 weeks) and Quercetin and (-)-Epicatechin (40 mg/kg BW each, i.p., every third day during the last 3 weeks) alone or in combination. Cu increased the concentration of lipid peroxides, decreased the number of erythrocytes, hemoglobin and hematocrit values and increased the activities of aspartate aminotransferase, alanine aminotransferase and lactate dehydrogenase. Coadministration of Quercetin and (-)-Epicatechin with Cu lowered the process of lipid peroxidation and restored examined hemato-biochemical parameters to control values. Our results indicate that Cu induced oxidative damage in erythrocytes, which led to anemia, while Quercetin and (-)-Epicatechin showed a protective effect on the hemato-biochemical processes in the blood of rats

Effect of aspartame on biochemical and oxidative stress parameters in rat blood

Aspartame (ASP) is one of the most widely used nonnutritive sweeteners. This study investigates the chronic effects of ASP on hematological and biochemical parameters, and its effects on the oxidative/antioxidative status in the red blood cells of Wistar albino rats. Rats were provided with ASP (40 mg/kg/daily for six weeks) in drinking water. Increased food and fluid intake was observed in the ASP-treated rats. Total body mass was significantly decreased in the ASP-treated rats. Treatment with ASP caused an increase in the concentrations of glucose, cholesterol, LDL-cholesterol, and in the activities of alanine aminotransferase (ALT), aspartate aminotransferase (AST) and lactate dehydrogenase (LDH), as well as a decrease in the levels of HDL-cholesterol in the serum. A significant decline in the number of white blood cells (WBC) was observed after ASP uptake. Based on the results we conclude that ASP induces oxidative stress, observed as an alteration of the glutathione redox status, which leads to increased concentrations of nitric oxide (NO) and lipid peroxides (LPO) in the red blood cells. Changes in biochemical parameters, lipid metabolism, as well as changes in the levels of oxidative stress markers and the appearance of signs of liver damage indicate that chronic use of ASP can lead to the development of hyperglycemia, hypercholesterolemia and associated diseases

Glutathione status in the blood of rats after reticulocytosis induced by phenylhydrazine and bleeding

In this experiment, we compared the in vivo effects of phenylhydrazine (PHZ) and bleeding treatment on the redox status and glutathione antioxidative mechanism parameters in the plasma and red blood cells (RBC) of rats. Results showed a lower level of reactive oxygen species (ROS), a higher level of lipid peroxidation and the effective antioxidative role of the glutathione system in the blood of bleeding rats. PHZ-treatment induced higher concentrations of ROS and an accumulation of oxidized glutathione in the plasma, while the glutathione system showed a satisfactory antioxidative capacity in the RBC of rats. When comparing the two anemic groups, the PHZ-treated rats showed marked oxidative stress in the plasma

Application of Replica Technique and SEM in Accuracy Measurement of Ceramic Crowns

The paper presents a comparative study of the measuring values of the marginal gap related to the ceramic crowns made by dental CAD/CAM system using the replica technique and SEM. The study was conducted using three experimental groups, which consisted of ceramic crowns manufactured by the Cerec CAD/CAM system. The scanning procedure was carried out using three specialized dental 3D digitization systems from the Cerec family - two types of extraoral optical scanning systems and an intraoral optical scanner. Measurements of the marginal gap were carried out using the replica technique and SEM. The comparison of aggregate values of the marginal gap using the replica technique showed a statistically significant difference between the systems. The measured values of marginal gaps of ceramic crowns using the replica technique were significantly lower compared to those measured by SEM. The results indicate that the choice of technique for measuring the accuracy of ceramic crowns influences the final results of investigation

Effects of cisplatin on lipid peroxidation and the glutathione redox status in the liver of male rats: The protective role of selenium

The role of oxidative stress in cisplatin (CP) toxicity and its prevention by pretreatment with selenium (Se) was investigated. Male Wistar albino rats were injected with a single dose of cisplatin (7.5 mg CP/kg b.m., i.p.) and selenium (6 mg Se/kg b.m, as Na2SeO3, i.p.) alone or in combination. The results suggest that CP intoxication induces oxidative stress and alters the glutathione redox status: reduced glutathione (GSH), oxidized glutathione (GSSG) and the GSH/GSSG ratio (GSH RI), resulting in increased lipid peroxidation (LPO) in rat liver. The pretreatment with selenium prior to CP treatment showed a protective effect against the toxic influence of CP on peroxidation of the membrane lipids and an altering of the glutathione redox status in the liver of rats. From our results we conclude that selenium functions as a potent antioxidant and suggest that it can control CP-induced hepatotoxicity in rats

Dietary Intake of Salt from Meat Products in Serbian Population

Salt intake above 5 g/day correlates with prevalence of hypertension and cardiovascular diseases (CVD). CVD, the leading cause of mortality and morbidity in Europe, account for 45% of all deaths, while, in Serbia in 2021, CVD accounted for 47.3%. The objective was to investigate salt content labelled on meat products from the Serbian market and estimate dietary exposure to salt from meat products in the Serbian population using consumption data. Data on salt content were collected from 339 meat products and classified in eight groups. Consumption data were collected using the EFSA EU Menu methodology (2017–2021) from 576 children and 3018 adults (145 pregnant women) in four geographical regions of Serbia. The highest salt content was in dry fermented sausages and dry meat, average 3.78 ± 0.37 g/100 g and 4.40 ± 1.21 g/100 g, respectively. The average intake of meat products is 45.21 ± 39.0 g/day and estimated daily salt intake from meat products per person is 1.192 g, which is 24% of the daily recommended amount. The actual meat product consumption and content of salt in meat products in Serbia present a risk factor for development of CVD and related comorbidities. A targeted strategy, policy and legislation for salt reduction are needed