Marija Petrovic

Inhibition of copper corrosion in acidic sulphate media by eco-friendly amino acid compound

This investigation aimed to study a “green” non-toxic biodegradable copper corrosion inhibitor in an acidic sodium sulphate solution. The methods used in the investigation of cysteine as a copper corrosion inhibitor in an acidic sodium sulphate solution were: potentiodynamic measurements, open circuit potential measurements, and chronoamperometric measurements. Optical microscopy was used in addition to electrochemical methods. Potentiodynamic measurements show that cysteine has good inhibitory properties in an acidic medium. Polarisation curves indicate that the presence of cysteine in a sulphate solution decreases the current density and that using various cysteine concentrations results in the formation of a protective film on the surface of the electrode due to the formation of the Cu(I)-cys complex. These results are confirmed by chronoamperometric measurements. Furthermore, it is clear from microphotographs that a protective film does form on copper electrode in the presence of cysteine. The Langmuir adsorption isotherm indicates that cysteine is chemisorbed on the surface of the electrode.

Influence of purine on copper behavior in neutral and alkaline sulfate solutions

The effect of purine (concentration range of 1.00 × 10−6–1.00 × 10−2 M) on the behavior of copper in a 0.5 M Na2SO4 solution (pH 7 and pH 9) was studied using the open circuit potential measurement, potentiodynamic polarization, and chronoamperometry. Potentiodynamic polarization shows that purine acts as a copper corrosion inhibitor in both alkaline and neutral sulfate solutions. The efficiency of inhibition increases as the purine concentration increases. Chronoamperometric results follow the same trend as the results of potentiodynamic polarization. The inhibition effect can also be observed visually by microscopic examination of the electrode surface. Purine is adsorbed on copper surface according to the Langmuir adsorption isotherm.

Socioeconomic Inequalities in Mental Health of Adult Population: Serbian National Health Survey

BACKGROUND The global burden of mental disorders is rising. In Serbia, anxiety is the leading cause of disability-adjusted life years. Serbia has no mental health survey at the population level. The information on prevalence of mental disorders and related socioeconomic inequalities are valuable for mental care improvement. AIMS To explore the prevalence of mental health disorders and socioeconomic inequalities in mental health of adult Serbian population, and to explore whether age years and employment status interact with mental health in urban and rural settlements. STUDY DESIGN Cross-sectional study. METHODS This study is an additional analysis of Serbian Health Survey 2006 that was carried out with standardized household questionnaires at the representative sample of 7673 randomly selected households - 15563 adults. The response rate was 93%. A multivariate logistic regression modeling highlighted the predictors of the 5 item Mental Health Inventory (MHI-5), and of chronic anxiety or depression within eight independent variables (age, gender, type of settlement, marital status and self-perceived health, education, employment status and Wealth Index). The significance level in descriptive statistics, chi square analysis and bivariate and multivariate logistic regressions was set at p<0.05. RESULTS Chronic anxiety or depression was seen in 4.9% of the respondents, and poor MHI-5 in 47% of respondents. Low education (Odds Ratios 1.32; 95% confidence intervals=1.16-1.51), unemployment (1.36; 1.18-1.56), single status (1.34; 1.23-1.45), and Wealth Index middle class (1.20; 1.08-1.32) or poor (1.33; 1.21-1.47) were significantly related with poor MHI-5. Unemployed persons in urban settlements had higher odds for poormMHI-5 than unemployed in rural areas (0.73; 0.59-0.89). Single (1.50; 1.26-1.78), unemployed (1.39; 1.07-1.80) and inactive respondents (1.42; 1.10-1.83) had a higher odds of chronic anxiety or depression than married individuals, or those with partner, and employed persons. Those with perceived good health status had lower odds for poor MHI-5, chronic anxiety or depression than those whose general health was average and poor. CONCLUSION Almost half of the population assessed their mental health as poor and 5% had diagnosed chronic anxiety or depression. Multi-sectoral socioeconomic and female-sensitive policies should be wisely tailored to reduce mental health inequalities contributed by differences in age, education, employment, marriage and the wealth status of the adult population.

Antioxidant Capacity Determination of Complex Samples and Individual Phenolics - Multilateral Approach

Antioxidant (AO) capacity of various medicinal plants extracts and phenolic compounds was assessed by the most widely used spectrophotometric assays such as ferric reducing antioxidant power (FRAP) and scavenging of 2,2-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) and 2,2-diphenyl-1-picrylhydrazyl (DPPH). In addition, two direct current (DC) polarographic assays, one based on a decrease of anodic current of [Hg(O2H)(OH)] - HydroxoPerhydroxoMercury(II) Complex (HPMC) formation in alkaline solution of H2O2, at the potential of mercury dissolution and another recently developed Mercury Reduction Antioxidant Power (MRAP), based on a a decrease of cathodic current of Hg(II) reduction were employed. Percentage of both currents decrease was plotted versus the volume of gradually added complex samples or the amount of individual ones and the slopes of these plots were used to express AO capacity. Total phenolic content (TPC) of extracts was determined by Folin- Ciocalteu (FC) assay. Correlations between applied assays were calculated by regression analysis. Relative Antioxidant Capacity Index (RACI), calculated by assigning equal weight to all applied assays and Phenolic Antioxidant Coefficients (PAC), calculated as a ratio between particular AO capacity and TPC, were used to achieve more comprehensive comparison between analyzed samples, as well as applied assays.

A new method for respiratory-volume monitoring based on long-period fibre gratings

Respiratory-volume monitoring is an indispensable part of mechanical ventilation. Here we present a new method of the respiratory-volume measurement based on a single fibre-optical long-period sensor of bending and the correlation between torso curvature and lung volume. Unlike the commonly used air-flow based measurement methods the proposed sensor is drift-free and immune to air-leaks. In the paper, we explain the working principle of sensors, a two-step calibration-test measurement procedure and present results that establish a linear correlation between the change in the local thorax curvature and the change of the lung volume. We also discuss the advantages and limitations of these sensors with respect to the current standards.