181 research outputs found

    Spectrographic Trace Analysis of Tin in the Presence of Large Amounts of Iron

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    It is possible to lower the inferior limit of spectrographic trace analysis of Sn in iron and steel1 if the Sn is separated by coprecipitation from the solution obtained by dissolving the sample in a mineral acid. The coprecipitation of Sn2+ 2•3 was in these experiments tested with CdS which is formed in the investigated solution. The amount of Cd2+ must be known because the spectrographic lines of Cd were used as reference lines, i. e. as an internal standard

    Dejstvo melatonina na regulaciju noradrenalinske neurotransmisije u mozgu, srcu i nadbubrežnim žlezdama u animalnom modelu depresije

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    The hippocampus is a brain structure highly sensitive to stress. Melatonin plays a role in maintaining the circadian rhythm, and its antioxidant properties have been confirmed. Chronic mild unpredictable stress (CUMS) is an animal model that mimics the role of chronic stress in the development of depression in humans. This model has been accepted as a paradigm that replicates many of the behavioral disorders that accompany depression. Male Wistar rats were exposed to CUMS for 4 weeks. During that period, the animals were treated with melatonin at a dose of 10 mg/kg body weight, i.p. Behavioral parameters were monitored in the open field test, elevated plus maze and the forced swim test. CUMS resulted in prolonged immobility in the forced swim test. Treatment of rats with melatonin reduced immobility compared to the control group, exhibiting an antidepressant effect. Melatonin normalized the amount of noradrenaline by acting on degradation enzymes and the VMAT2 transporter in the hippocampus. This study showed that melatonin exhibits antidepressant effects in an animal model of depression. In the open field test, animals treated with melatonin spent more time in the center of the arena, indicating its anxiolytic effect. Our results showed decreased gene expression for α1-, α2- and β2-adrenoreceptor in the hippocampus of stressed rats, while there was no change in gene expression for β1-adrenoreceptor. Melatonin treatment in CUMS rats prevented stress-induced decreases in α1- and β2-adrenoreceptor mRNA and protein levels, while not affecting β1- and α2-adrenoreceptor mRNA and protein levels. Reduction of catecholamine biosynthesis and enhancement of their reuptake in the adrenal medulla of rats exposed to CUMS is associated with the beneficial effects of chronic melatonin treatment. The observed beneficial effects of melatonin in the heart via enhanced uptake and reduced degradation are most likely compensatory mechanisms that protect cardiomyocytes from the deleterious effects of excessive noradrenaline stimulation. The obtained results contribute to a better understanding of the molecular mechanisms of action of melatonin by monitoring changes in the expression of genes responsible for the process of synthesis, uptake and storage of catecholamines in the brain, cardiovascular system and medulla of the adrenal glands as sites of primary synthesis of catecholamines

    Construction of an autogenerator dynamic model applicable to nuclear processes

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    We propose a new method for constructing a mathematical model of a non-linear system in an auto-oscillation regime. The method is based on the divergence of a vector field having a constant value along the corresponding periodical motion. The variants of the obtained model could be used for describing nuclear processes that are represented by the systems of differential equations analogous to that of the presented model

    Arterijska vaskularizacija amigdale psa

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    We investigated the vascularization of the amygdala of the dog using various contrast agents injected into the internal carotid and vertebral artery. Subsequent clearance of the tissues gives us an opportunity to study the finest capillary network in the amygdala. The corticomedial part of the amygdala has a good vascularization given by the rostral and caudal choroid arteries. The rostral choroid gives off a rich capillary net to the nucleus centralis (NCE), its pars lateralis (NCEL) and pars medialis (NCEM). Nucleus medialis (NM) is poorly vascularized compared to the central nuclei. The massa intercalata (MI) also has a delicate artery around which there is a fine net of capillaries. Nucleus corticalis (NCO) and area enthorhinalis (AER) are better vascularized by the subpial blood vessel. The caudal choroid, a branch of the caudal cerebral artery is a source of subpial capillaries. The basolateral part of the amygdala is very well vascularized by the rostral choroid artery, a branch of the middle cerebral, especially the nucleus basolateralis (NBL) and nucleus lateralis posterior (NLP). The nucleus basomedialis (NBM) is poorly vascularize by the rostral choroid artery . The amygdala, is served by the middle cerebral artery, via its branch, the rostral choroid, and the caudal cerebral artery via its branch the caudal choroid artery. Every amygdala nucleus has its own central artery around which is formed a rich net of capillaries.Proučavanje vaskularizacije amigdale psa vršeno je upotrebom različitih kontrasnih sredstava injiciranih u a. carotis interna i a. vertebralis a prosvetljavanje tkiva daje mogućnost da se prouči i najfinija vaskularna mreža u amigdali. Kortikomedijalni deo amigdale vaskularišu a. choroidea rostralis i a. choroidea caudalis. A. choroidea rostralis, daje bogatu mrežu kapilara u NCE (nucleus centralis) i njegovom lateralnom i medijalnom delu (NCEL i NCEM). Nucleus medialis (NME) je slabije vaskularisan u poredjenju sa vaskularizacijom NCE. Massa intercalata (MI) je takodje snabdevena bogatom mrežom kapilara. A. choroidea caudalis, kao subpialna arterija, vaskulariše NCO (nucleus corticalis) i AER (area enthorhinalis). Bazolateralni deo amigdale vaskulariše samo a. choroid rostralis. Bogata mreža kapilara uočava se u NBL (nucleus basolateralis) i NLP (nucleus lateralis posterior) a nešto siromašnija u NBM (nucleus basomedialis). Krv u amigdalu dovode dve arterije: a. choroidea rostralis, grana od a. cerebri media, i a. choroidea caudalis, grana od a. cerebri caudalis. Svaki nukleus amigdale ima svoju centralnu arteriju i oko nje jako razvijenu mrežu kapilara

    The effect of thermophoresis on the discharge parameters in complex plasma experiments

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    Thermophoresis is a tool often applied in complex plasma experiments. One of the usual stated benefits over other experimental tools is that changes induced by thermophoresis neither directly depend on, nor directly influence, the plasma parameters. From electronic data, plasma emission profiles in the sheath, and Langmuir probe data in the plasma bulk, we conclude that this assumption does not hold. An important effect on the levitation of dust particles in argon plasma is observed as well. The reason behind the changes in plasma parameters seems to be the change in neutral atom density accompanying the increased gas temperature while running at constant pressure.Comment: 14 pages, 12 figure

    Liver cystic echinococcosis in humans — a study of 30 cases

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    The aim of this study is to demonstrate the clinical manifestations and diagnostic approach to liver hydatid disease and suggest its treatment. The prospective study was carried out on 30 patients with liver hydatidosis. Hepatologic examinations were based on: medical history, physical examination, biochemical and serological tests, ultrasonography and computed tomography scanning. Twenty-five (83.3 %) patients underwent radical cyst resection, while in 5 (16.7 %) cases liver resection with left lobectomy was also performed. Hydatid cyst was histopathologically verified in all the patients. Our results showed that the patients with multiple cysts had impaired functional liver tests significantly more often than patients with unilocular cyst. In addition, ultrasonography and computed tomography scans are the valid imaging procedures in diagnosis. Radical, surgical resection of hepatic hydatid cysts is the goal of treatment

    Allergen labelling in meat, dairy and cereal products from the Serbian market

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    Allergens in food are a great health risk, because of the ratio of severity of problems compared to small amounts of ingested allergen. Since 2014, Serbian producers and importers of food have been obliged to declare allergens from the list of Codex Alimentarius on the product packaging. Surveillance of different meat, diary, and cereal product took place in 2016, with aim of checking if the Serbian regulatory requirements for labelling of allergens in food are being fulfilled. Out of 68 different meat products, 20 were not labelled for allergens. Thirty-six labels of various dairy products were examined revealing that allergen information was included on 27 of them. Only one of eight examined cereal products did not have allergen labelling

    Pljevlja lignite carbon emission charateristics

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    The anthropogenic emission of GHG especially CO has to be limited and reduced due to their impact on global warming and climate change. Combustion of fossil fuels in the energy sector has a dominant share in total GHG emissions. In order to reduce GHG emission, European Union established a scheme for GHG allowance trading within the community, and the implementation of the European Union emission trading scheme, which is a key to GHG reduction in a cost-effective way. An important part of emission trading scheme is prescribed methodology for monitoring, reporting, and verification of the emission of GHG including characterization of the local fuels combusted by the energy sector. This paper presents lignite characteristics from open-pit mine Borovica-Pljevlja, which has highest coal production in Montenegro (>1.2 Mt per year), including evaluation of its carbon emission factor based on the laboratory analysis of 72 coal samples. Testing of the samples included proximate and ultimate analysis, as well as, net calorific value determination. In accordance with the obtained results, linear correlations between net calorific value and combustible matter content, carbon content and combustible matter content, hydrogen content and combustible matter content, carbon content and net calorific value, were established. Finally, the non-linear analytical correlation between carbon emission factor and net calorific value for Pljevlja lignite was proposed, as a base for the precise calculation of CO emission evaluation
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