159 research outputs found
Uticaj lajnera na zapaljenje zubne pulpe
Introduction The study included application of liners and dental composites in to cavities of six experimental animals - rabbits (Oryctolagus cuniculus). Objective The aim of the study was to investigate rabbit dental pulp response to different liners. Methods Cavity preparation for class V were made on the maxillary central incisors and one lower incisor, while the second lower incisor served as a control tooth. These teeth were restored with the use of one of the following liners - Calcimol LC, ANA Liner and Fuji II LC Improved, and Ceram-X mono dental composite. After an observation period of five days animals were sacrificed and prepared for histological analysis. The existence and degree of the pulp inflammation was determined by using a light microscope. Results Results showed that the used liners do not cause distortion of the structure and continuity of the odontoblastic layer. Inflammation was not registered in the control group, while in each group of tested materials one tooth with mild signs of hyperemia was registered. Results showed that all three tested liners demonstrated favorable effects on the pulp of the tooth and did not lead to inflammatory reactions. Conclusion Histological analysis of the dental pulp of experimental animals suggests that the liners used in this study do not compromise the integrity of the odontoblastic layer, if it is applied over a thin layer of dentin. In each group of tested materials one tooth with mild signs of hyperemia and vasodilation was registered.Uvod Ispitivanje je obuhvatilo primenu lajnera i kompozitnog materijala u kavitete intaktnih zuba šest eksperimentalnih životinja - kunića. Cilj rada Cilj istraživanja je bio da se proveri uticaj različitih lajnera na nastanak i stepen zapaljenja pulpe nakon primene u kavitete zuba kunića. Metode rada Kod svake životinje su urađene preparacije V klase na dva gornja centralna sekutića i na jednom donjem sekutiću, dok je drugi donji sekutić služio kao kontrolni zub. U preparisane kavitete su aplikovani materijali koji su indikovani za primenu kod dubokih kaviteta neposredno pre postavljanja kompozitnih restauracija na zubima: Calcimol LC, ANA Liner i Fuji II LC improved. Svi kaviteti su restaurisani kompozitnim materialom CeramX-mono. Posle opservacionog perioda od pet dana životinje su žrtvovane i pripremljene za histopatološku analizu. Rezultati Svetlosnom mikroskopijom analizirani su postojanje i stepen zapaljenja u zubnoj pulpi. Rezultati su pokazali da korišćeni lajneri ne narušavaju strukturu i kontinuitet odontoblastnog sloja. Na zubima kontrolne grupe nije uočeno zapaljenje, dok je kod testiranih materijala u svakoj grupi zabeležen jedan zub sa blagim znacima hiperemije. Dobijeni rezultati su pokazali da su sva tri ispitana lajnera povoljno uticala na pulpu zuba i nakon aplikacije nisu doveli do zapaljenjskih reakcija u pulpi. Zaključak Histološka analiza zubne pulpe eksperimentalnih životinja je pokazala da lajneri korišćeni u ovom istraživanju ne narušavaju integritet odontoblasta eksperimentalnih životinja ukoliko se nanose preko tankog sloja dentina. Utvrđeno je samo postojanje blage hiperemije i vazodilatacije u po jednom uzorku pulpe zuba zaštićenih testiranim lajnerima
Fiziološki aspekti ponašanja krmača i prasadi u toku laktacionog perioda
Maternal ability represents complex interactions between different forms of behaviour and physiological characteristics. Behaviour and metabolic processes are partly under the control of endocrine and nervous systems. Sows are different from other mammals, in that sows bear a large number mature baby, capable immediately to suckling. Post partum anabolic processes become catabolic, giving priority to dairy gland in relation to other tissues. Maximum secretated milk takes place between 2. and 3. week. Sows lost in body mass and it is appeared the change in value of some bloods parameters. Haemotologic analyses have suggested the increase in total number of leukocytes and neutrophilic granulocytes and the decrease in the number of lymphocytes, monocytes and eosinophils on the first day postpartum. In the third and fourth week of lactation a statistically significant fall in the number of leukocytes and granulocytes in relation to the first day was observed, along with a significant increase in limphocytes, monocytes and eosinophils. Erythrocyte count, haemoglobin concentration and haematocrit value decreased during the lactation period. Level of glucose in plasma is low (it is decreasing for more than 50%), while the level of urea is high, due to huge proteins available. It can also be noticed that there is a high mobilisation of body fat an increasing level of NEFA (non-esterified fatty acid). Secretion of milk is under control prolactin and oxytocin. Oxytocin affects on maternal behaviour and prolactin is linked with timing of suck.Materinska sposobnost predstavlja kompleksne interakcije između različitih oblika ponašanja i fizioloških karakteristika. Ponašanje i metabolički procesi su delimično pod kontrolom endokrinog i nervnog sistema. Krmače se razlikuju od drugih sisara po tome što rađaju veliki broj zrelih mladih sposobnih da odmah sisaju. Nakon partusa anabolički procesi prelaze u kataboličke, dajući tako prioritet mlečnoj žlezdi u odnosu na druga tkiva. Maksimalna sekrecija mleka odvija se između 2. i 3. nedelje. Krmače gube telesnu masu i dolazi do promena vrednosti pojedinih parametara u krvi. Hematološke analize su ukazale na povećanje ukupnog broja leukocita i neutrofilnih granulocita i smanjenje broja limfocita, monocita i eozinofila prvog dana po partusu. Treće i četvrte nedelje laktacije, došlo je do statistički značajnog pada broja leukocita i granulocita u odnosu na prvi dan, a značajnog porasta limfocita, monocita i eozinofila. Broj eritrocita, koncentracija hemoglobina i vrednost hematokrita smanjuju se tokom laktacionog perida. Nivo glukoze u plazmi je veoma nizak (niži je za preko 50%), dok je nivo ureje visok usled obimnog iskorišćavanja proteina. Takođe je ustanovljeno da značajna mobilizacija telesnih masti dovodi do povećanja nivoa NEFA (nezasićenih masnih kiselina). Sekrecija mleka je pod kontrolom prolaktina i oksitocina. Oksitocin utiče na materinsko ponašanje a prolaktin je u korelaciji sa dužinom sisanja
Gustine i viskoznosti binarnih sistema sa N,N-dimetilanilinom i tetra etilen glikolom dimetil etrom ili N-metil-2-pyrolidonom, kao potencijalni rastvarači za procese odsumporavanja dimnih gasova
Sulfur oxides are emitted as one of the products in the process of combusting solid fossil fuels in thermal power plants, especially the Kolubara and Kostolac lignites in the Republic of Serbia. In order to reduce the emission level of the indirect Greenhouse gases (GHG) from stationary sources, it is inevitable to implement flue gas desulfurization (FGD) technology. In addition to the classic limestone process, technological procedures based on the physical or chemical absorption of sulfur oxides in the solvent and its thermal regeneration are becoming increasingly common. In order to properly design and optimize the process, it is significant to precisely determine the thermophysical properties of pure components and their mixtures. The paper presents the results of determining the density and viscosity of two binary mixtures, N,N-Dimethylaniline (N,N-DMA) + Tetra Ethylene Glycol Dimethyl Ether (TEGDME) and N,N-Dimethylaniline (N,N-DMA) + N-methyl-2-pyrrolidone (NMP). Measurements were made using a densitometer Anton Paar DMA 5000 and Stabinger viscometer Anton Paar SVM 3000/G2, at atmospheric pressure. The obtained experimental results are presented as a function of temperature and N,N-DMA mole fraction. N,N-DMA belongs to the group of amines, and it has been used as a sorbent for purification of flue gases in processes with thermal regeneration (CANSOLV, Sulphidine and ASARCO processes). The other two organic solvents are TEGDME and NMP. Special attention was paid to NMP due to its low cost and low viscosity, with its favorable properties, making it competitive as a solvent for FGD. TEGDME is a polar solvent, but it is not selective to SO2 and other gaseous components, so NMP has been suggested as an alternative solution. A regenerative process for SO2 removal, with TEGDME, has already found commercial application (Solinox process). NMP is already industrially used as a solvent in Lurgi's Purisol process, due to its nature for selective desulfurization of flue gases.Oksidi sumpora emituju se kao jedan od proizvoda u procesu sagorevanja čvrstih fosilnih goriva u termoelektranama, posebno kolubarskog i kostolačkog lignita u Republici Srbiji. Da bi se smanjio nivo emisije indirektnih gasova staklene bašte (GHG) iz stacionarnih izvora, neizbežna je primena tehnologije odsumporavanja dimnih gasova (FGD). Pored klasičnog krečnjačkog postupka, sve su češć i tehnološki postupci zasnovani na fizičkoj ili hemijskoj apsorpciji sumpornih oksida u rastvaraču i njegovoj termičkoj regeneraciji. Da bi se pravilno dizajnirao i optimizovao proces, važno je precizno odrediti termofizička svojstva čistih komponenti i njihovih smeša. U radu su prikazani rezultati određivanja gustine i viskoziteta dve binarne smeše, N,N-dimetilanilin (N,N-DMA) + tetra etilen glikol dimetil etar (TEGDME) i N,N-dimetilanilin (N,N-DMA) + N-metil-2-pirolidon (NMP). Merenja su vršena pomoću gustinomera Anton Paar DMA 5000 i Stabinger viskozimetra Anton Paar SVM 3000/G2, na atmosferskom pritisku. Dobijeni eksperimentalni rezultati su prikazani kao funkcija temperature i molskog udela N,N-DMA. N,N-DMA pripada grupi amina, a korišć en je kao sorbent za prečišć avanje dimnih gasova u procesima sa termičkom regeneracijom (CANSOLV, Sulphidine i ASARCO procesi). Druga dva organska rastvarača su TEGDME i NMP. Posebna pažnja je posveć ena NMP-u zbog niske cene i niskog viskoziteta, sa svojim povoljnim svojstvima, što ga čini konkurentnim kao rastvarač za FGD. TEGDME je polarni rastvarač, ali nije selektivan ka SO2 i druge gasovite komponente, pa je NMP predložen kao alternativno rešenje. Regenerativni proces za uklanjanje SO2, sa TEGDME, već je našao komercijalnu primenu (Solinox proces). NMP se već industrijski koristi kao rastvarač u Lurgi's Purisol procesu, zbog svoje prirode za selektivno odsumporavanje dimnih gasova.Procesing '24 : 37. Međunarodni kongres o procesnoj industriji : zbornik radova - Proceedings, 29-31. maj 2024, Beogra
Antioxidant Effects of Glechoma hederacea as a Food Additive
The antioxidant properties of Glechoma hederacea L. (Lamiaceae), of Serbian origin, were studied in respect to its potential use in foodstuffs. Ethanol-water (8:2, v/v) and purified ethyl acetate extracts of the plant were found to possess significant antioxidant activity. Tests were performed on two different substrates, prime steam pork lard and active-carbon-treated edible sunflower oil, using Schaal oven test storage conditions at 60 degrees C. The ethanol-water and purified ethyl acetate extracts of G. hederacea showed strong concentration-dependent antioxidant activity. On the contrary, under the Rancimat method conditions at 120 degrees C, the ethanol-water extract showed significantly stronger antioxidant activity, in comparison with the other tested extracts. All activities were compared with commercial antioxidants, such as BHA and a tocopherol mixture, respectively. For the first time, the activity of the flavonol quercetagetin was determined
Viskoznost binarne smeše DMA + 2-butanol za potencijalnu upotrebu kao rastvarača za regenerativne procese odsumporavanja dimnih gasova
Sulfur dioxide (SO2) is an environmental pollutant with multiple harmful effects on biological world. One of the main emission sources are industrial activities in thermal power plants, foundries and steel mills which involve combustion of fossil fuels containing sulfur, such as coal and oil. Initial step towards removal of SO2from flue gases was the so-called limestone process, a wet non-regenerative process that even today is the mostused flue gas desulfurization method. However, wet regenerative processes with gas absorption in liquid organic solvent and thermal regeneration recently have found practical application. Processes based on n,n-dimethylaniline (DMA) have alre-ady been patented and industrially applied. This solvent has high selectivity towards SO2in compa-rison to the other components of flue gas like CO2, and excellent binding capability by the 214• 32ndINTERNATIONAL CONGRESS ON PROCESS INDUSTRYmechanisms of chemical absorption, but main disadvantage is its high toxicity. On the other hand, in more ambient friendly 2-butanol binding of sulfur-dioxide occurs by means of physical absorption. Investigations have shown that mixtures of physical and chemical solvents usually show better cha-racteristics regarding binding capacityand selectivity than traditionally used aqueous solutions of amines, due to the synergetic effect.One of the most important thermophysical properties of solvents, necessary for process and equipment design is dynamic viscosity. In this investigation viscosity of binary mixture DMA + 2-butanol is experimentally determined in temperature and concentration range and correlated afterwards using different literature models. These correlations present useful method to acquire reliable data necessary for fluid flow analysis and mass and heat transfer calculations, since experi-mental values for desired process conditions are often not available. In this study, two or three-pa-rameter Eyring-UNIQUAC, Eyring-NRTL and McAllister models were used, while model that co-uples Eyring equation, Peng-Robinson equation of state and van der Waals mixing rule, was tested for simultaneous calculation of density and viscosity. The obtained results are presented and discu-ssed regarding potential application, limitations and complexity of used approach and models.Sumpor dioksid (SO2) je zagađivač životne sredine sa višestrukim štetnim efektima na biološki svet. Jedan od glavnih izvora emisije su industrijske aktivnosti u termoelektranama, livnicama i železarama, koje uključuju sagorevanje fosilnih goriva koja sadrže sumpor, kao što su ugalj i nafta. Početni korak u uklanjanju SO2 iz dimnih gasova bio je takozvani krečnjački postupak, mokri neregenerativni proces koji je i danas najčešće korišćen metod odsumporavanja dimnih gasova. Međutim, mokri regenerativni procesi sa apsorpcijom gasa u tečnom organskom rastvaraču i termalnom regeneracijom nedavno su našli praktičnu primenu. Procesi zasnovani na n,n-dimetilanilinu (DMA) su već patentirani i industrijski primenjeni. Ovaj rastvarač ima visoku selektivnost prema SO2 u poređenju sa drugim komponentama dimnog gasa kao što je CO2, i odličnu sposobnost vezivanja mehanizmima hemijske apsorpcije, ali glavni nedostatak je visoka toksičnost. S druge strane, u, sa stanovišta životne sredine prihvatljivijem, 2-butanolu do vezivanja sumpor-dioksida dolazi fizičkom apsorpcijom. Istraživanja su pokazala da smeše fizičkih i hemijskih rastvarača obično pokazuju bolje karakteristike u pogledu mogućnosti vezivanja i selektivnosti od tradicionalno korišćenih vodenih rastvora amina, zbog sinergetskog efekta. Jedno od najvažnijih termofizičkih svojstava rastvarača, neophodno za simulaciju procesa i proračun opreme, je dinamička viskoznost. U ovom istraživanju, viskoznost binarne smeše DMA + 2-butanol eksperimentalno je određena u temperaturnom i koncentracionom opsegu i nakon toga korelisana korišćenjem različitih literaturnih modela. Ove korelacije predstavljaju korisnu metodu za dobijanje pouzdanih podataka potrebnih za analizu protoka fluida i proračune prenosa mase i toplote, jer eksperimentalne vrednosti za željene uslove procesa često nisu dostupne. U ovom istraživanju korišćeni su dvo- ili troparametarski modeli Eyring-UNIQUAC, Eyring-NRTL i McAllister, dok je model koji povezuje Eyring jednačinu, Peng-Robinson jednačinu stanja i van der Waals pravilo mešanja testiran za istovremeno izračunavanje gustine i viskoznosti. Dobijeni rezultati su prikazani i diskutovani u pogledu potencijalne primene, ograničenja i složenosti korišćenog pristupa i modela
Cytokinins and urea derivatives stimulate seed germination in Lotus corniculatus L.
We studied the effects of various cytokinins and urea derivatives on germination of aged seeds of in Lotus corniculatus L. The following substances were applied: N6-isoprenoid cytokinins (isopentenyl adenine and zeatin), adenine sulfate, N6-aromatic cytokinins (kinetin, benzyladenine) and their N9-ribosides, N-benzyl-9-(2- tetrahydropyranyl)adenine, and urea derivatives (diphenylurea, thidiazuron, and chloro-pyridyl phenylurea). With the exception of adenine sulfate, all cytokinins increased the percentage of seed germination up to twofold, depending on their kind and concentration. It is concluded that cytokinins may be among the missing factors in aged seeds of L. corniculatus contributing to the implementation of their full germination potential. They could be used to improve germination of both freshly harvested and aged seed samples, if necessary.
Electrical Characterization and Impedance Response of Lanthanum Doped Barium Titanate Ceramics
The dielectric permittivity and dissipation factor of La-doped and undoped BaTiO3 were investigated as a function of frequency and temperature. The impedance response was used to study the electrical properties of La-doped BaTiO3 over the temperature range from room temperature (RT) to 350 degrees C. La-doped and undoped BaTiO3, obtained by a modified Pechini method, were sintered in air at 1300 degrees C for 2 and 16 hours. The impedance spectra were analyzed in terms of equivalent circuits involving resistors, capacitors and constant phase elements (CPE). The most suitable electrical circuit for the interpretation of experimental results is found to be the equivalent circuit consisting of resistors and CPE elements which replace the capacitor elements. The contribution of grain boundary resistance to the total resistance of a system is remarkable at low temperature. Dielectric permittivity of doped BaTiO3 was in the range of 8000 to 12000 at 1 kHz and the dissipation factor was less than 1%
Numerical study of transient three-dimensional heat conduction problem with a moving heat source
A numerical study of transient three-dimensional heat conduction problem with a moving source is presented. For numerical solution Douglas-Gunn alternating direction implicit method is applied and for the moving heat source flux distribution Gaussian function is used. An influence on numerical solution of input parameters figuring in flux boundary conditions is examined. This include parameters appearing in Gaussian function and heat transfer coefficient from free convection boundaries. Sensitivity of cooling time from 800 to 500°C with respect to input parameters is also tested
- …