A Study of Biased and Unbiased Stochastic Algorithms for Solving Integral Equations

In this paper we propose and analyse a new unbiased stochastic method for solving a class of integral equations, namely the second kind Fredholm integral equations. We study and compare three possible approaches to compute linear functionals of the integral under consideration: i) biased Monte Carlo method based on evaluation of truncated Liouville-Neumann series, ii) transformation of this problem into the problem of computing a finite number of integrals, and iii) unbiased stochastic approach. Five Monte Carlo algorithms for numerical integration have been applied for approach (ii). Error balancing of both stochastic and systematic errors has been discussed and applied during the numerical implementation of the biased algorithms. Extensive numerical experiments have been performed to support the theoretical studies regarding the convergence rate of Monte Carlo methods for numerical integration done in our previous studies. We compare the results obtained by some of the best biased stochastic approaches with the results obtained by the proposed unbiased approach. Conclusions about the applicability and efficiency of the algorithms have been drawn

Instalation For Induction Heating For Testing Thermo Sensors

With constant development and improvement of management systems in modern technological processes, in cars, in production lines and machinery and other fields are increasingly entering the use of different sensors. These sensors are tested on special test simulators, simulating the conditions for a long time close to their work. Often the temperature is in the range of 700-900°C. To achieve these temperatures, most environmentally safe and effective heating of the sensors can be achieved by induction heating of housing them. The object of this report is installation for induction heating system as part of the simulator to test the vibration and temperature thermal sensors

Birth Size of Neonates and Its Association with Seasonality

The aim of the study is to evaluate the relationship between the season of birth and the birth weight and length of Bulgarian newborns.The weight and length data of 6517 (6098 full-term and 419 preterm) live births in 2000–2001 were collected from the birth registry of II Hospital of Obstetrics and Gynaecology “Sheynovo”, Sofia, Bulgaria. Statistical analyses were done using the SPSS 16 software for Windows: descriptive statistics; the t-test (p<0.05); One-Way ANOVA, (Tukey, HSD-test, p<0.05) and the Pearson’s correlation. The sunshine dura-tion data for 2000 and 2001 were collected at the Sofia Meteorological Station.The mean weight of Bulgarian neonates born in 2000-2001 was 3389.8 g in boys and 3261.8 g in girls. The average newborn’s length was 51.0 cm and 50.3 cm in boys and girls, respectively. In all seasons, significant gender differences were observed with a priority for boys (p≤0.001). The winter period was identified with a peak in birth length for both sexes, and spring and summer were the seasons with the lowest values for boys and girls, respectively. A significant positive correlation between birth length and the daily amount of sunshine during the prenatal period was found (p<0.001).Seasonal fluctuations influenced weight and length in Bulgarian neonates. The results obtained in this study can be useful in prenatal diagnostics, neonatal care, and health prevention of pregnant women and neonates

Cadmium and copper absorption mediated by a poly(vinyl alcohol)-b-polyacrylonitrile based micelle/Trichosporon cutaneum cell system

The micelles of a recently synthesized copolymer of poly(vinyl alcohol)-b-polyacrylonitrile added to the growth solution of the filamentous yeast Trichosporon cutaneum strain R57 led to the formation of a binary system consisting of micelles and cells. The resulting micelle/cell system was studied as a model for the removal of toxic concentrations of heavy-metal ions (cadmium and copper) from aqueous solutions. The ion-removal efficiency mediated by this system was higher than for free-floating cells. The copper-removal efficiency from the solution reached a level of 65% after 24 h of cultivation, whereas the cadmium-removal efficiency reached 62% after 6 h of growth. For comparison, the free-floating cells removed 42% of copper and only 38% of cadmium from the solutions. The effects of surface interactions between the cells and polymer micelles on the biosorption capacity of the cells are discussed in the article

Novel Fluorescent Benzimidazole-Hydrazone-Loaded Micellar Carriers for Controlled Release: Impact on Cell Toxicity, Nuclear and Microtubule Alterations in Breast Cancer Cells

Fluorescent micellar carriers with controlled release of a novel anticancer drug were developed to enable intracellular imaging and cancer treatment simultaneously. The nanosized fluorescent micellar systems were embedded with a novel anticancer drug via the self-assembling behavior of well-defined block copolymers based on amphiphilic poly(acrylic acid)-block-poly(n-butyl acrylate) (PAA-b-PnBA) copolymer obtained by Atom Transfer Radical Polymerization (ATRP) and hydrophobic anticancer benzimidazole-hydrazone drug (BzH). Through this method, well-defined nanosized fluorescent micelles were obtained consisting of a hydrophilic PAA shell and a hydrophobic PnBA core embedded with the BzH drug due to the hydrophobic interactions, thus reaching very high encapsulation efficiency. The size, morphology, and fluorescent properties of blank and drug-loaded micelles were investigated using dynamic light scattering (DLS), transmission electron microscopy (TEM), and fluorescent spectroscopy, respectively. Additionally, after 72 h of incubation, drug-loaded micelles released 3.25 μM of BzH, which was spectrophotometrically determined. The BzH drug-loaded micelles were found to exhibit enhanced antiproliferative and cytotoxic effects on MDA-MB-231 cells, with long-lasting effects on microtubule organization, with apoptotic alterations and preferential localization in the perinuclear space of cancer cells. In contrast, the antitumor effect of BzH alone or incorporated in micelles on non-cancerous cells MCF-10A was relatively weak