Antimicrobial activity of natural soaps tested by Bioscreen methodology

The aim of this study was to combine the utilization of waste frying oils within soap making process in order to make useful and environmentally friendly solutions and development of methods for determination of the antimicrobial effect of those created products. Soaps were made from edible oils which are fried in laboratory conditions. The antimicrobial activity of soaps was done against Staphylococcus aureus species as one of the representatives of the human skin microbiome. Two methods were applied: agar dilution method and the method including kinetics following on Bioscreen micro­biology reader. In the first method, the number of CFU was followed on agar medium with and without different soap solutions after incubation for 24 hours at 30 °C. The result for IC50 (inhibition concentration for 50% of population) was 0.08 mg/mL. Minimal inhibition concentration was detected at 0.41 mg/mL and minimal bactericidal concentration was observed at > 0.75 mg/mL for selected soap solution. Soap concentrations of 0.3 mg/mL of soaps (made from fresh and fried oil) were used for Bioscreen assessment with measurement on every hour during the 7 hours of incubation at 30 °C. 5-second sequence of shaking of the microplate was applied before each measurement which was done at the wavelength of 610 nm. The growth coefficients of the culture with soap solutions added and from the growth of culture only were compared. The growth of S. aureus subjected to soaps made from fresh and fried oils was inhibited 55.3% and 69.7% respectively against the control during the first seven hours of incubation. From results obtained, it was concluded that there is a great potential of the Bioscreen as a method for further studies on antibacterial activity of soaps made from waste frying oils

Effect of chemical composition on the microstructure, hardness and electrical conductivity profiles of the Bi-Ge-In alloys

© 2020, Association of Metallurgical Engineers of Serbia. All rights reserved. In this study, the microstructure, hardness, and electrical properties of selected ternary Bi-Ge-In alloys were investigated. Isothermal sections of the Bi-Ge-In system at 25, 200, and 300 °C were extrapolated using optimized thermodynamic parameters from the literature. The used experimental techniques include optical microscopy, X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and energy dispersion spectrometry (EDS), Brinell hardness, and electrical conductivity measurements. The results of EDS phase composition analysis were compared with the calculated isothermal sections and a good overall agreement was reached. The results of the XRD were also in line with the predicted phase balance. By using ANOVA analysis and experimental results of Brinell hardness and electrical conductivity, a mathematical model was suggested for the calculation of these properties along with all composition ranges. The appropriated mathematical model was subsequently used for the prediction of hardness and electrical conductivity throughout the whole composition range

Mechanical and electrical properties of the Bi-Ge-Sn alloys

© 2020, Association of Metallurgical Engineers of Serbia. All rights reserved. Mechanical and electrical properties of the ternary Bi-Ge-Sn alloys were investigated in this study. Calculation of isothermal section at 200, 300, and 25 ºC was carried out by using optimized thermodynamic parameters for the constitutive binary systems. Microstructures of alloys were observed by using optical microscopy and scanning electron microscopy (SEM). Phases in microstructures have been detected by X-ray diffraction (XRD) analysis and compositions of the phase by energy dispersive spectrometry (EDS). EDS results were compared with the predicted isothermal section at 200 and 300 ºC, and good agreement has been reached between them. The Brinell hardness and electrical conductivity of selected alloys were measured. Through ANOVA analysis and application of the obtained results, an appropriate mathematical model is proposed for every composition of alloys. By using the appropriated mathematical model for Brinell hardness and electrical conductivity, isolines for those properties were presented

Experts system based on the neural network and mobile database in the field galvanic metal coating

© 2018 Published by Faculty of Engineering. In a modern era of information technologies, everyday changes are more numerous and various. One of those changes is related to the greater use of mobile devices in a decision making processes. They may be used in the field of automation and improvement of production processes. Their main purpose may be seen as the achievement of optimal production quality, lower production costs, timely deliveries, rational management of material and information flows. Having this in mind, it may be said that interactive data processing from different data sources and the application of artificial intelligence methods is possible within the field of metal coating data processing and prediction. In this paper, novel developed model and expert system, which consists of mobile databases and neural network for the prediction of quality of coating has been presented. Input data obtained from the databases are related to the starting conditions of deposition and the quality of the given coating material, while the target data are related to the thickness and roughness of the material surfaces. Application of the presented solution may confirm the possibility of integration of mobile databases and neural networks within a mobile expert system in the field of modern production systems

Hospital infections rate and health staff density in a neonatology department

© 2017, Serbian Medical Society. All rights reserved. Objective. The aim of our study was to compare staffing trends for physicians and nurses with hospital infections (HIs) rate at a neonatology department of tertiary care health facility. Methods. The prospective cohort study was conducted at Neonatology Department, Clinical Centre Kragujevac, Serbia. The incidences of neonates with HIs were calculated for each of the quarters during the 5-year period. The data about the number and structure of staff for each quarter of the study period were collected from the official work schedule lists of the department. Results. This study registered a total of 272 HIs occurring in 264 neonates. The incidence rate of patients with HIs was 13.36% and the incidence density of HIs was 5.85 per 1,000 patient-days. In the observed period the trend of incidence rate of patients with HIs was stable, but the trend of incidence density of HIs was increasing, however without statistical significance. The highest incidence rates of patients with HIs were recorded in the third quarter of all observed years respectively: 17.44% in 2012, 16.74% in 2013, 23.47% in 2014, 18.18% in 2015 and 22.74 in 2016. The average number of nurses in the first shift ranged from 5.0 to 7.0, but in second shift was 3.0 to 4.0 only, and the least number of nurses worked in the third quarter of each year. The average number of physicians in the first shift ranged from 2.33 to 4.47 and they were also the fewest in numbers in the third quarter. We observed strong negative correlation between the average incidence rate of patients with HIs and the average number of nurses in the first shift (r=-0.977, p=0.023). Conclusion. Optimal nurse and physician staffing of neonatal departments in developing countries and the avoidance of inter-quarter variations in number of staff at duty would decrease the incidence of HIs and probably create overall savings of the hospital budget

Psychometric evaluation and validation of the Serbian version of Reading the Mind in the Eyes test8

© 2017 by the Serbian Psychological Association. Reading the Mind in the Eyes test (RMET) is one of the most popular and widely used measures of individual differences in Theory of Mind (ToM) capabilities. Despite demonstrating good validity in differentiating various clinical groups exhibiting ToM deficits from unimpaired controls, previous studies raised the question of the RMET's homogeneity, latent structure, and reliability. The aim of this study is to provide evidence on psychometric properties, latent structure, and validity of the newly adapted Serbian version of the RMET. In total, 260 participants (61.9% females) took part in the study. The sample consisted of both unimpaired controls (76.5%), and a clinical group of participants that are believed to demonstrate ToM deficits (23.5%), namely, persons diagnosed with schizophrenia and bipolar disorder (54.1% females). RMET has demonstrated fair psychometric properties (KMO = .723; α = .747; H1 = .076; H5 = .465), successfully differentiating between clinical group and control [F (1,254) = 26.175, p < .001, ηp2 = .093], while typical gender differences in performance were found only in control group. Tests of several models based on the previous literature revealed that the affect-specific factors underlying performance on RMET demonstrate poor fit. The best fitting model obtained included reduced scale with a single-factor underlying the test's performance (TLI = .953, CFI = .958, RMSEA = .020). Based on the fit parameters we propose 18-item short-form of the Serbian version of RMET (KMO = .797; α = .728; H1 = .129; H5 = .677) for economic, reliable and valid measurement of ToM abilities

Development of collisional data base for elementary processes of electron scattering by atoms and molecules

We present a progress report on the development of the Belgrade electron/molecule data base which is hosted by The Institute of Physics, University of Belgrade and The Astronomical Observatory Belgrade. The data base has been developed under the standards of Virtual Atomic Molecular Data Centre (VAMDC) project which provides a common portal for several European data bases that maintain atomic and molecular data. The Belgrade data base (BEAMDB) covers collisional data of electron interactions with atoms and molecules in the form of differential (DCS) and integrated cross sections as well as energy loss spectra. The final goal of BEAMDB becoming both a node within the VAMDC consortium and within the radiation damage RADAM data base has been achieved

Plasma Parameters From Quasi-Thermal Noise Observed by Parker Solar Probe: A New Model for the Antenna Response

International audienceQuasi-Thermal Noise (QTN) spectroscopy is a reliable diagnostic routinely used for measuring electron density and temperature in space plasmas. The observed spectrum depends on both antenna geometry and plasma kinetic properties. Parker solar probe (PSP), launched in 2018, is equipped with an antenna system consisting of two linear dipoles with a significant gap between the antenna arms. Such a configuration, not utilized on previous missions, cannot be completely described by current models of the antenna response function. In this work, we calculate the current distribution and the corresponding response function for the PSP antenna geometry, and use these results to generate synthetic QTN spectra. Applying this model to the Encounter 7 observations from PSP provides accurate estimations of electron density and temperature, which are in very good agreement with particle analyzer measurements