427 research outputs found

    The attitudes of students of psychology in grading knowledge and creativity

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    Starting from Gilford’s differentiation of thinking into convergent and divergent, research was carried out into the attitudes of the students of psychology towards quality and the objectivity of professor’s gradings, representation of certain elements of grading, as well as the ways of forming the final grade on an exa

    Iron concentrations in atherosclerotic plaque and serum in patients with carotid atherosclerosis

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    The aim of this study was to investigate the iron concentrations in serum and carotid plaque in patients with different morphology of carotid atherosclerotic plaque and compared with other metal ions. Carotid endarterectomy due to the significant atherosclerotic stenosis was performed in 91 patients. Control group consisted of 27 patients, without carotid atherosclerosis. Atherosclerotic plaques were divided into four morphological groups, according to ultrasonic and intraoperative characteristics. Iron, copper and zinc concentration in plaque, carotid artery and serum were measured by spectrophotometry. Serum iron concentrations were higher in patients with hemorrhagic plaques in comparison to the control group (4.7 μmol/l ± 1.2 vs. 2.1 μmol/l ± 0.8, p < 0.05). Iron concentrations were higher in patients with hemorrhagic plaques in comparison to fibrolipid plaques (72.1 ± 14.3 μg/g vs. 39.3 ± 22.9 μg/g; p < 0.05). Negative significant correlation was found for zinc in serum and plaque iron concentration in patients (p < 0.05). We also demonstrated positive significant correlation for copper and iron in serum (p < 0.05). The data obtained in the current study are consistent with the hypothesis that high iron levels may contribute to atherosclerosis and its complications as factors in a multifactorial disease

    A New K means Grey Wolf Algorithm for Engineering Problems

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    Purpose: The development of metaheuristic algorithms has increased by researchers to use them extensively in the field of business, science, and engineering. One of the common metaheuristic optimization algorithms is called Grey Wolf Optimization (GWO). The algorithm works based on imitation of the wolves' searching and the process of attacking grey wolves. The main purpose of this paper to overcome the GWO problem which is trapping into local optima. Design or Methodology or Approach: In this paper, the K-means clustering algorithm is used to enhance the performance of the original Grey Wolf Optimization by dividing the population into different parts. The proposed algorithm is called K-means clustering Grey Wolf Optimization (KMGWO). Findings: Results illustrate the efficiency of KMGWO is superior to GWO. To evaluate the performance of the KMGWO, KMGWO applied to solve 10 CEC2019 benchmark test functions. Results prove that KMGWO is better compared to GWO. KMGWO is also compared to Cat Swarm Optimization (CSO), Whale Optimization Algorithm-Bat Algorithm (WOA-BAT), and WOA, so, KMGWO achieves the first rank in terms of performance. Statistical results proved that KMGWO achieved a higher significant value compared to the compared algorithms. Also, the KMGWO is used to solve a pressure vessel design problem and it has outperformed results. Originality/value: Results prove that KMGWO is superior to GWO. KMGWO is also compared to cat swarm optimization (CSO), whale optimization algorithm-bat algorithm (WOA-BAT), WOA, and GWO so KMGWO achieved the first rank in terms of performance. Also, the KMGWO is used to solve a classical engineering problem and it is superiorComment: 15 pages. World Journal of Engineering, 202

    Reconstitution of a Minimal DNA Replicase From Pseudomonas Aeruginosa and Stimulation by Non-Cognate Auxiliary Factors

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    DNA polymerase III holoenzyme is responsible for chromosomal replication in bacteria. The components and functions of Escherichia coli DNA polymerase III holoenzyme have been studied extensively. Here, we report the reconstitution of replicase activity by essential components of DNA polymerase holoenzyme from the pathogen Pseudomonas aeruginosa. We have expressed and purified the processivity factor (β), single-stranded DNA-binding protein, a complex containing the polymerase (α) and exonuclease (ϵ) subunits, and the essential components of the DnaX complex (τ3δδ′). Efficient primer elongation requires the presence of αϵ, β, and τ3δδ′. Pseudomonas aeruginosa αϵ can substitute completely for E. coli polymerase III in E. coli holoenzyme reconstitution assays. Pseudomonas β and τ3δδ′ exhibit a 10-fold lower activity relative to their E. coli counterparts in E. coli holoenzyme reconstitution assays. Although the Pseudomonas counterpart to the E. coli ψ subunit was not apparent in sequence similarity searches, addition of purified E. coli χ and ψ (components of the DnaX complex) increases the apparent specific activity of the Pseudomonas τ3δδ′ complex ∼10-fold and enables the reconstituted enzyme to function better under physiological salt conditions

    Influence of ambience temperature and operational-constructive parameters on landfill gas generation - Case study Novi Sad

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    Researches in the area of landfill gas generation and energy utilization are currently underway and widespread in the world for several reasons: reducing effects of greenhouse gases, possibilities for utilizing alternative energy sources, reducing conventional energy resources exploitation, and environmental protection. First part of this research is conducted with an aim to establish the influence of meteorological parameters, primarily ambience temperature, on the methane generation processes at Novi Sad landfill. The second part of the research refers to functional characteristics of landfill such as the waste age, closing practice, and the age of certain parts of landfill body, as well as the waste depth and quantity of generated methane. Based on several years of investigation, it is concluded that methane generation varies in the range of 0-34 vol. % m3/m3, and that seasonal variations have significant influence on methane generation. At low temperatures, during winter, methane generation and migration is stagnant while in summer periods, due to higher temperatures, the process of methane generation is more intensive

    Metal content in the surface soils of industrial areas in Novi Sad

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    The scope of this study was to investigate the heavy metal content in the industrial soils of Novi Sad, Serbia. A total of twenty topsoil samples (0–10 cm depth) were collected. The chemical properties of soil as well as the particle size distribution of soil (<2 mm fraction) were determined. Pseudo-total concentrations of cadmium, copper, lead, and zinc were measured using the ICP-OES device. Total mercury content in the samples was analysed using a Direct Mercury Analyzer (DMA) 80 Milestone. The results showed that the conc- entrations of Cu and Zn were found to be elevated at two locations. The concentration of Cd was very high at the same locations. Results revealed that no elevated values were detected for Pb at any location; all values were at the level of those in natural, unpolluted soils

    Copper and zinc concentrations in atherosclerotic plaque and serum in relation to lipid metabolism in patients with carotid atherosclerosis

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    © 2015, Institut za Vojnomedicinske Naucne Informacije/Documentaciju. All rights reserved. Background/Aim. Some oligoelements are now investigated as possibly having a role in atherosclerosis. The aim of this study was to compare the concentrations of copper and zinc in the serum and carotid plaque and parameters of lipid metabolism in patients with different morphology of carotid atherosclerotic plaque. Methods. Carotid endarterectomy due to the significant atherosclerotic stenosis was performed in 91 patients (mean age 64 ± 7). The control group consisted of 27 patients (mean age 58 ± 9), without carotid atherosclerosis. Atheroscletoric plaques were divided into four morphological groups, according to ultrasonic and intraoperative characteristics. Copper and zinc concentrations in the plaque, carotid artery and serum were measured by atomic absorption spectrophotometry. Results. Serum copper concentrations were statistically significantly higher in the patients with hemorrhagic in comparison to those with calcified plaque (1.2 ± 0.9 μmol/L vs 0.7 ± 0.2 μmol/L, respectively; p = 0.021). Zinc concentrations were statistically significantly lower in plaques of the patients with fibrolipid in comparison to those with calcified plaques (22.1 ± 16.3 μg/g vs 38.4 ± 25.8 μg/g, respectively; p = 0.024). A negative significant correlation was found for zinc and triglycerides in the serum in all the patients (r = -0.52, p = 0.025). In the control group we also demonstrated a positive significant correlation for low-density lipoprotein cholesterol and copper in the serum (r = 0.54, p = 0.04). Conclusion. The data obtained in the current study are consistent with the hypothesis that high copper and lower zinc levels may contribute to atherosclerosis and its sequelae as factors in a multifactorial disease. Further studies are necessary in order to conclude whether high concentration of copper and zinc in the serum could be risk factors for atherosclesrosis

    DNA Polymerase III Holoenzyme From Thermus Thermophilus Identification Expression Purification of Components and use to Reconstitute a Processive Replicase

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    DNA replication in bacteria is performed by a specialized multicomponent replicase, the DNA polymerase III holoenzyme, that consist of three essential components: a polymerase, the β sliding clamp processivity factor, and the DnaX complex clamp-loader. We report here the assembly of the minimal functional holoenzyme from Thermus thermophilus (Tth), an extreme thermophile. The minimal holoenzyme consists of α (pol III catalytic subunit), β (sliding clamp processivity factor), and the essential DnaX (τ/γ), δ and δ′ components of the DnaX complex. We show with purified recombinant proteins that these five components are required for rapid and processive DNA synthesis on long single-stranded DNA templates. Subunit interactions known to occur in DNA polymerase III holoenzyme from mesophilic bacteria including δ-δ′ interaction, δδ′-τ/γ complex formation, and α-τ interaction, also occur within the Tth enzyme. As in mesophilic holoenzymes, in the presence of a primed DNA template, these subunits assemble into a stable initiation complex in an ATP-dependent manner. However, in contrast to replicative polymerases from mesophilic bacteria, Tth holoenzyme is efficient only at temperatures above 50 °C, both with regard to initiation complex formation and processive DNA synthesis. The minimalTth DNA polymerase III holoenzyme displays an elongation rate of 350 bp/s at 72 °C and a processivity of greater than 8.6 kilobases, the length of the template that is fully replicated after a single association event
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