One–pot synthesis of hydrophobic hydroxyapatite nano particles

A highly hydrophobic oleic acid functionalized hydroxyapatite nanoparticles were obtained by the solvothermal method. Water solutions of reactants were added in mixture of oleic acid, triethanolamine and ethanol, which was then treated in Teflon lined autoclave. The chemical composition, size and morphology of as obtained particles were determined using XRD, FT IR, FE SEM and LD PSA. In addition, sintering behaviour and microstructure of prepared material were also examined

Study on a standard for grounding systems realization

Grounding systems of objects inside power facilities are very often realized as structures consisting of protective electrodes’ system placed in the object foundation, and neutral electrodes’ system placed at a specified distance from the object. Official standards and publications recommend a minimal value for the distance between the protective and the neutral part of grounding structures, so that the influence of one on another can be neglected. We analyze several practical implementations of grounding structures and demonstrate that the minimal distance is actually much smaller than that recommended by the standards

Uticaj dugotrajnog zvučnog stresa na histološku građu nadbubrežne žlezde brojlera

The aim of this paper is to examine the effect of different sound stress duration on adrenal gland of broiler chickens of different age. The experiments were conducted on 90 HYBRO broiler chickens, divided into nine groups (each group consisting of 10 birds) by different age and lenght of sound stress duration. The chickens were exposed to sound stress in sound attenuated building using a fire alarm bell (95 dB) for stress sessions lasted 120 min every day. The histological structure of adrenal gland was analyzed by light microscopy. The results indicate that adrenal gland is sensitive on this kind of stress and sound as stressor could introduce organism in stress reaction. Adrenal glands of broilers exposed to sound stress characterized by marked hyperemia, hypertrophy of interrenal cells, smaller affinity for staining of chromaffin cells compared with control groups. According to our results, degree of histological changes of adrenal gland under the influence of sound stress depends on the length of exposure and age of chickens.Cilj ovog rada je da ispita uticaj različite dužine trajanja zvučnog stresa na histološku građu nadbubrežnih žlezda brojlerskih pilića u različitim uzrastima. Ogled je izveden na 90 HYBRO brojlerskih pilića, podeljenih u 9 grupa u skladu sa uzrastom i dužinom izlaganja stresu. Pilići su zvučnom stresu bili izlagani u zvučno izolovanim objektima uz korišćenje požarnog alarmnog zvona (95dB) u trajanju od 120 min svakog dana. Histološka građa nadbubrežnih žlezda je analizirana svetlosnim mikroskopom. Rezultati ukazuju da je nadbubrežna žlezda osetljiva na ovu vrstu stresa i da zvuk, kao stresor, može da uvede organizam u stresnu reakciju. Nadbubrežne žlezde pilića izlaganih zvučnom stresu karakteriše značajna hiperemija, hipertrofija interrenalnih ćelija, manji afinitet prema bojenju hromafinih ćelija u odnosu na kontrolnu grupu. U skladu sa ovim rezultatima, stepen histoloških promena nadbubrežne žlezde pod uticajem zvučnog stresa zavisi i od dužine izlaganja i uzrasta pilića

The influence of powder characteristics on two-step sintering behavior of hydroxyapatite

Fabrication of full dense ceramic materials on the basis of hydroxyapatite (HAp) and biphasic calcium phosphate (BCP) with controllable microstructural and compositional characteristics attracts considerable efforts. Various synthesis and sintering methods were applied in order to achieve desirable material properties. In this study different nanopowders were produced and processed via two-step sintering (TSS) approach. Characterization of synthesized nanopowders were done by XRD, BET, FE-SEM, TEM and thermal analysis methods, while microstructural and chemical characterizations of sintered samples were performed through FE-SEM and XRD analysis. A possibility for obtaining full dense ceramics with suppressed grain growth is discussed on the basis of inherent nanopowders characteristics. Certain attention would be paid on thermal behavior of Ca-deficient HAp systems

Morphometric Analysis of Nonsclerosed Glomeruli Size and Connective Tissue Content during the Aging Process

Number of sclerotic glomeruli increases during the aging process. Consequently, majority of remained nonsclerosed glomeruli become hypertrophic and some of them sclerotic, too. The aim of this study was to quantify the size and connective tissue content of nonsclerosed glomeruli and to evaluate the percentage of hypertrophic ones in examined human cases during the aging. Material was right kidney's tissue of 30 cadavers obtained during routine autopsies. Cadavers were without previously diagnosed kidney disease, diabetes, hypertension, or any other systemic disease. Tissue specimens were routinely prepared for histological and morphometric analysis. Images of the histological slices were analyzed and captured under 400x magnification with digital camera. Further they were morphometrically and statistically analyzed with ImageJ and NCSS-PASS software. Multiple and linear regression of obtained morphometric parameters showed significant increase of glomerular connective tissue area and percentage. Cluster analysis showed the presence of two types of glomeruli. Second type was characterized with significantly larger size, connective tissue content, and significantly lower cellularity, in relation to the first type. Such glomeruli might be considered as hypertrophic. First type of glomeruli was predominant in younger cases, while second type of glomeruli was predominant in cases older than 55 years

Triethanolamine as an efficient cosolvent for biodiesel production by cao-catalyzed sunflower oil ethanolysis: An optimization study

Triethanolamine was applied as an efficient „green“ cosolvent for biodiesel production by CaO-catalyzed ethanolysis of sunflower oil. The reaction was conducted in a batch stirred reactor and optimized with respect to the reaction temperature (61.6-78.4 °C), the ethanol-to-oil molar ratio (7:1-17:1) and the cosolvent loading (3-36 % of the oil weight) by using a rotatable central composite design (RCCD) combined with the response surface methodology (RSM). The optimal reaction conditions were found to be: the ethanol-to-oil molar ratio of 9:1, the reaction temperature of 75 °C and the cosolvent loading of 30 % to oil weight, which resulted in the predicted and actual fatty acid ethyl ester (FAEE) contents of 98.8 % and 97.9±1.3 %, respectively, achieved within only 20 min of the reaction. Also, high FAEE contents were obtained with expired sunflower oil, hempseed oil and waste lard. X-ray diffraction analysis (XRD) was used to understand the changes in the CaO phase. The CaO catalyst can be used without any treatment in two consecutive cycles. Due to the calcium leaching into the product, an additional purification stage must be included in the overall process.Supplementary material: [http://cherry.chem.bg.ac.rs/handle/123456789/3798

Supplementary data for article: Đokić-Stojanović, D. R.; Todorović, Z. B.; Troter, D. Z.; Stamenković, O. S.; Veselinović, L. M.; Zdujić, M. V.; Manojlović, D. D.; Veljković, V. B. Triethanolamine as an Efficient Cosolvent for Biodiesel Production by Cao-Catalyzed Sunflower Oil Ethanolysis: An Optimization Study. Hemijska Industrija 2019, 73 (6), 351–362. https://doi.org/10.2298/HEMIND190822033D

Supplementary material for: [https://doi.org/10.2298/HEMIND190822033D]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/3797

Supplementary data for article: Đokić-Stojanović, D. R.; Todorović, Z. B.; Troter, D. Z.; Stamenković, O. S.; Veselinović, L. M.; Zdujić, M. V.; Manojlović, D. D.; Veljković, V. B. Triethanolamine as an Efficient Cosolvent for Biodiesel Production by Cao-Catalyzed Sunflower Oil Ethanolysis: An Optimization Study. Hemijska Industrija 2019, 73 (6), 351–362. https://doi.org/10.2298/HEMIND190822033D

Supplementary material for: [https://doi.org/10.2298/HEMIND190822033D]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/3797

Full density calcium phosphate bioceramics from nanopowders by sintering

Poster presented at the Adriatic School of Nanoscience – ASON-1, Dubrovnik, Croatia, September 19–23, 201

Influence of various cosolvents on the calcium oxide-catalyzed ethanolysis of sunflower oil

Ten organic solvents (triethanolamine, diethanolamine, ethylene glycol, methyl ethyl ketone, n-hexane, triethylamine, ethylene glycol dimethyl ether, glycerol, tetrahydrofuran and dioxane) were applied as cosolvents in the CaO-catalyzed ethanolysis of sunflower oil performed in a batch stirred reactor under the following reaction conditions: temperature 70 °C, ethanol-to-oil mole ratio 12:1, initial catalyst concentration 1.374 mol·L -1 and amount of cosolvent 20 % based on the oil amount. The main goals were to assess the effect of the used cosolvents on the synthesis of fatty acid ethyl esters (FAEE) and to select the most efficient one with respect to the final FAEE content, reaction duration and safety profile. In the absence of any cosolvent, the reaction was rather slow, providing a FAEE content of only 89.7±1.7 % after 4 h. Of the tested cosolvents, diethanolamine, triethanolamine and ethylene glycol significantly accelerated the ethanolysis reaction, whereby the last two provided a final FAEE content of 93.1±2.1 and 94.1±1.5 %, respectively, within 0.5 h. However, because of its safety profile, triethanolamine was selected as the best cosolvent for the ethanolysis of sunflower oil catalyzed by calcined CaO