Ecophysiological and biochemical traits of three herbaceous plants growing on the disposed coal combustion fly ash of different weathering stage

The ecophysiological and biochemical traits of Calamagrostis epigejos (Roth.) Festuca rubra L. and Oenothera biennis L. growing on two fly ash lagoons of different weathering stage (L1-3 years and L2-11 years) of the “Nikola Tesla- A” thermoelectric plant (Obrenovac, Serbia) were studied. Species-dependent variations were observed at the L1 lagoon; the greatest vitality (Fv/Fm and Fm/Fo) followed by higher photopigment and total phenolic contents were measured in O. biennis in relation to C. epigejos (p<0.001) and F. rubra (p<0.001). At the L2 site, higher vitality was found in O. biennis (p<0.001) and F. rubra (p<0.01) compared to C. epigejos. O. biennis had the highest photosynthetic capacity. The results obtained in this study indicate that all examined species maintained a level of photosynthesis that allowed them to survive and grow under the stressful conditions in ash lagoons, albeit with lower than optimal success. [Projekat Ministarstva nauke Republike Srbije, br. 173018

On the influence of spike shape at supersonic flow past blunt bodies

Da bi se eliminsala pojava jakog udarnog talasa pri nadzvučnom opstrujavanju projektila, koja zanačajno povećava otpor pri letu krozvazduh, na njegov vrh montira se igla. U radu se daju rezultati eksperimentalnog istraživanja uticaja oblika igle na aerodinamičke koeficijente (uzgona, otpora, momenta propinjanja, kao i položaj centra pritiska) pri nadzvučnom opstrujavanju tela zaobljenog vrha. Eksperiment je izveden u aereotunelu, za jednu vrednost Mahovog i Rejnoldsovog broja, kao i za jednu vrednost napadnog ugla α = 2o. Za telo bez igle, kao i za telo sa četiri različita modela igle merene su aerodinamičke sile i momenti. U radu su predloženi kriterijumi za procenu uticaja igle zasnovani isključivo na rezultataima dobijrenim vizualizacijom strujanja. Igla najboljih karakteristika, od ispitanih konfiguracija, izabrana na osnovu izmerenih aerodinamičkih koeficijenata, uklapa se u ove kvalitativne kriterijume.In order to eliminate the appearance of a strong shock wave at a supersonic flight of a missile, which considerably increases the drag during its flight through the air, a spike is mounted on its nose. Presented paper offers the results of an experimental analysis of the influence of the spike's shape on the aerodynamic coefficients (drag, lift and pitching moment coefficient, as well as the location of the center of pressure) at supersonic flow past blunt-nosed body. The experiment was carried out in a wind tunnel, for one value of Mach and Reynolds numbers, and for one value of the angles of attack, α = 2o. For the body without spike, and with four different spike shapes, the aerodynamic forces and moment were measured. Using only the photos obtained by Schlieren visualization of the flow, the paper proposes a criterion of estimating the aerodynamic effect of the spike shape. The best spike shape from the experimental set of spikes, selected by the measurement of the aerodynamic coefficients, coincided with this qualitative criterion

On the influence of spike shape at supersonic flow past blunt bodies

Da bi se eliminsala pojava jakog udarnog talasa pri nadzvučnom opstrujavanju projektila, koja zanačajno povećava otpor pri letu krozvazduh, na njegov vrh montira se igla. U radu se daju rezultati eksperimentalnog istraživanja uticaja oblika igle na aerodinamičke koeficijente (uzgona, otpora, momenta propinjanja, kao i položaj centra pritiska) pri nadzvučnom opstrujavanju tela zaobljenog vrha. Eksperiment je izveden u aereotunelu, za jednu vrednost Mahovog i Rejnoldsovog broja, kao i za jednu vrednost napadnog ugla α = 2o. Za telo bez igle, kao i za telo sa četiri različita modela igle merene su aerodinamičke sile i momenti. U radu su predloženi kriterijumi za procenu uticaja igle zasnovani isključivo na rezultataima dobijrenim vizualizacijom strujanja. Igla najboljih karakteristika, od ispitanih konfiguracija, izabrana na osnovu izmerenih aerodinamičkih koeficijenata, uklapa se u ove kvalitativne kriterijume.In order to eliminate the appearance of a strong shock wave at a supersonic flight of a missile, which considerably increases the drag during its flight through the air, a spike is mounted on its nose. Presented paper offers the results of an experimental analysis of the influence of the spike's shape on the aerodynamic coefficients (drag, lift and pitching moment coefficient, as well as the location of the center of pressure) at supersonic flow past blunt-nosed body. The experiment was carried out in a wind tunnel, for one value of Mach and Reynolds numbers, and for one value of the angles of attack, α = 2o. For the body without spike, and with four different spike shapes, the aerodynamic forces and moment were measured. Using only the photos obtained by Schlieren visualization of the flow, the paper proposes a criterion of estimating the aerodynamic effect of the spike shape. The best spike shape from the experimental set of spikes, selected by the measurement of the aerodynamic coefficients, coincided with this qualitative criterion

Changes of Hippocampal Noradrenergic Capacity in Stress Condition

This study aimed to investigate the effects of chronic restraint stress (CRS) on the protein levels of dopamine-β-hydroxylase (DBH), noradrenaline transporter (NET), vesicular monoamine transporter 2 (VMAT2) and brain-derived neurotrophic factor (BDNF), as well as the concentration of noradrenaline (NA) in the rat hippocampus. The investigated parameters were quantified by Western blot analyses and ELISA kits. We found that CRS increased the protein levels of DBH by 30 %, VMAT2 by 11 %, BDNF by 11 % and the concentration of NA by 104 %, but decreased the protein levels of NET by 16 % in the hippocampus of chronically stressed rats. The molecular mechanisms by which CRS increased the hippocampal NA level are an important adaptive phenomenon of the noradrenergic system in the stress condition. © 2020 Charles University. All rights reserved

Uticaj oblika i strukture čestica na tečljivost elektrolitičkog bakarnog praha II - eksperimentalna potvrda modela reprezentativne čestice praha

An analysis of the effects of the shape, surface structure and size distribution of particles on the flow ability of the copper powder was performed. It is shown that the most important property of the particles of a powder, regarding the flow ability of the powder, is the surface structure of the particles.Izvedena je analiza uticaja oblika, površinske strukture i raspodele veličina čestica na tečljivost bakarnog praha. Pokazano je da površinska struktura predstavlja najvažnije svojstvo čestice praha u odnosu na njegovu tečljivost

Organoleptic properties of Lamb meat: Factor of quality

Organoleptic propertyies of thermally processed lamb meat of mixed breed lambs of the mixed Svrljig strain and Domestic Pramenka, and Merinolandschaf sheep, and meat of the Wuerttemberg Merino lambs. Sensory methods of meat examination were used, with the participation of six trained evaluators. The results of the investigations in which numerical-descriptive scales were used are presented in tables. A salty, sour and bitter taste were expressed in a very small degree in both groups of samples. A sweet taste, although of low intensity, significantly differed among the examined groups. No differences were established regarding juiciness and tenderness, but statistically significant differences were established in aftertaste and overall acceptibility in favor of meat of the first group of lambs

Animal Models for Chronic Stress-Induced Oxidative Stress in the Spleen: The Role of Exercise and Catecholaminergic System

We examined the effects of daily exercise on the gene expression of catecholamine biosynthetic enzymes (tyrosine hydroxylase (TH), dopamine-β-hydroxylase (DBH), and phenyl ethanolamine N-methyltransferase (PNMT)), vesicular monoamine transporter 2 (VMAT 2), antioxidant enzymes (superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx)), concentrations of catecholamines (noradrenaline (NA) and adrenaline (A)) and malondialdehyde (MDA), activities of monoamine oxidase (MAO), and antioxidant enzymes in the spleen of chronically psychosocially stressed rats. Exposure of chronically stressed rats to exercise increased the levels of PNMT protein by 19%, VMAT 2 mRNA by 100%, NA by 160%, and A by 140%; decreased/unchanged MAO enzyme activity; returned concentrations of MDA to control level; and increased CAT and GPx mRNA levels (50% and 150%, respectively). Exercise induced the accumulation of the catecholamines and a decrease of stress-induced oxidative stress in the spleen, which may significantly affect the immune-neuroendocrine interactions in stress conditions. Also, exercise induced the catecholaminergic system and antioxidant defense to become more ready to a novel stressor, which indicates that exercise may induce potentially positive physiological adaptations. Our combined model of chronic social isolation and long-term daily treadmill running in rats may be a good animal model in the research of therapeutic role of exercise in human disease caused by chronic stress

Antioxidant Status and Sex Hormones in Women with Simple Endometrial Hyperplasia

Cancer of the reproductive tract is an important source of morbidity and mortality among women worldwide. Factors affecting endometrial cancer and endometrial hyperplasia are known to be similar. Endometrial hyperplasia is abnormal proliferation of the glands and the stroma resulting in architectural and cytological modifications. Due to hormonal changes, this condition is most common among women who are nearing the menopause or have reached the menopause. Antioxidant system has a role in preventing cancer initiation and promotion. Since the carcinogenesis occurs in several stages, it is likely that the antioxidant defense depends on the type of cell and tissue. The objective of this study was to investigate whether antioxidant enzymes activities and lipid hydroperoxides concentration in patients with endometrial hyperplasia are influenced by the changes in sex hormones level (estradiol, progesterone, FSH, and LH) during the menstrual cycle and in postmenopause. The material we used consisted of blood and endometrial tissue specimens of women diagnosed with endometrial hyperplasia simplex. Patients were divided in groups depending on the phase of the menstrual cycle: follicular phase, luteal phase and postmenopause. The activities of antioxidant enzymes and the lipid hydroperoxides level were compared among the phases to test the differences and a linear regression model was used to evaluate the associations between hormone levels and antioxidant/oxidant variables. In the blood of examined patients, we observed a phase-related changes of LOOH concentrations. Significant negative correlation between FSH concentration and GR activity (r= -0.42, p<0.05) and significant positive correlation between LH and LOOH concentrations (r= 0.038, p<0.05) was found. In hyperplasia simplex tissue we recorded significant phase-related changes of LOOH level as well as of AO enzyme activities. SOD and CAT had similar activity pattern, which was higher in luteal phase and in postmenopause, compared to follicular phase (p<0.05). GPx and GR activities did not show any statistical difference. Also, negative correlation between progesterone and GR activity (r=-0.036, p<0.05) was observed. Hormonal influence on AO system is of importance in gynecological diseases etiology since they may promote cell proliferation but are also used in conservative therapy, especially for hyperplasia simplex. However, the role of ROS production as a risk factor for endometrial hyperplasia still needs to be clarified as well as the role of AO status in response to gonadotropins and sex steroids

Histamin u ribi dostupnoj na tržištu Srbije u 2018. godini

Histamine is a biogen amin, which is formed by decarboxylation of the histidine amino acid, under the action of the L-histidine-decarboxylase enzyme. High level of free histidine in fish meat, bacterial histidin decarboxylase activity and high temperature of storage elevate the level of histamine. Among the most important factors that can affect the level of histamine in fish meat are the type of fish and the method of its preservation. In order to determine this dependence, 1030 samples of frozen fish (tuna, mackerel, sardines and sprat) and 167 samples of canned fish (tuna, sardines and mackerel) were monitored for histamine content by ELISA method. It was determined a lower concentration of histamine in frozen fish (from 5.71 mg/kg to 18.03 mg/kg) compared to canned fish (from 15.03 mg/kg to 110.6 mg/kg). The highest histamine concentrations were found in the mackerel samples, regardless of the preservation method (110.6 mg/kg in canned mackerel and 18.03 mg/kg in frozen mackerel), which were significantly higher compared to the histamine levels found in cans of tuna and sardines (p ˂0.0001). Of the total number of samples, three samples (two samples of canned sardines and one sample of canned mackerel) were declared unsafe for human health. In most of the analyzed samples, the level of determined histamine was relatively low, which confirms adequate implementation of control protocols and efficant surveillance of products placed on the Serbian market.Histamin je bioaktivni amin, koji nastaje u reakciji dekarboksilacije aminokiseline histidina, pod dejstvom enzima Lhistidin dekarboksilaze. Visok nivo slobodnog histidina u mesu ribe, aktivnost enzim produkujućih bakterija i visoke temperature skladištenja deluju predisponirajuće na sintezu histamina. Među najznačajnije faktore koji utiču na koncentraciju histamina u mesu ribe jesu vrsta ribe i metod njenog konzervisanja. U cilju utvrđivanja ove zavisnosti, uzorci zamrznute ribe (tune, skuše, sardine i papaline) i ribe u konzervi (tune, sardine i skuše) su analizirani ELISA metodom. Utvrđene su niže koncentracije histamina u uzorcima zamrznute ribe (od 5.71 mg/kg do 18.03 mg/kg) u poređenju sa konzervama od ribe (od 15.03 mg/kg do 110.6 mg/kg). Najviše koncentracije histamina su ustanovljene u uzorcima skuše, bez obzira na metod konzervisanja (110.6 mg/kg u konzervama od skuše i 18.03 mg/kg u zamrznutoj skuši), koje su bile i statistički značajno veće u odnosu na konzerve tune i konzerve sardine (p ˂0.0001). Od ukupnog broja uzoraka, samo tri uzorka (dva uzorka sardine u konzervi i jedan uzorak skuše u konzervi) su proglašeni nebezbednim za zdravlje ljudi. U najvećem broju ispitanih uzoraka izmerene su relativno niske koncentracije histamina, što ukazuje na adekvatno sprovođenje kontrole i nadzora nad proizvodima koji se plasiraju u promet na srpskom tržištu

ASCORBIC ACID MODULATES SPONTANEOUS THYMOCYTE APOPTOSIS

The aim of the paper was to analyze the effect of various concentrations of ascorbic acid on spontaneous apoptosis of lymphocytes.About 58% of all thymocytes are subjected to a spontaneous apoptosis, after 24-hour cultivation in the complete medium. The number of apoptotic thymocytes was much lower in the culture with different concentrations of ascorbic acid. The most dramatic effect was detected in the culture with the highest concentration of ascorbic acid (10000 μg/ml). In this culture, the number of apoptotic thymocytes was about 32%. These results, compared with the results of spontaneous apoptosis, show that the most significant inhibition of apoptosis was detected in the culture with 10000 μg/ml of ascorbic acid. High concentration of ascorbic acid can inhibit spontaneous apoptosis of thymocytes. Such inhibition of T cell apoptosis, as the effector cells in immune system, can represent one of the major factors by which ascorbic acid influence the immune system