469 research outputs found
Regulation of antioxidant enzyme activities in female rat brain by ovarian steroids
The sex steroids produce their effects by acting on numerous target tissues and organs, such as the reproductive organs, bone tissue and cartilage, peripheral blood vessels as well as the central nervous system (CNS). In our studies we have monitored the change of enzyme activity of the antioxidant (AO) system in the brain of female rats depending on the ovarian steroids. We have chosen it as a new parameter that might represent an important indicator of the changes within the CNS, bearing in mind the biological importance of the enzymes of the AO system. The experimental results of our study indicate that the enzyme activity of the AO system in the brain tissue of female rats shows a certain dependence on the concentration of ovarian hormones, progesterone and estradiol, in the organism. Study of the activity of the enzymes of the AO system in the brain of female rats depending on the influence of ovarian hormones can answer whether the action of ovarian steroids on the CNS includes maintenance of a dynamic equilibrium of free radicals in the neurons
Izolacija i karakterizacija autohtonih sojeva bakterija mlečne kiseline izdvojenih iz sjeničkog sira
Lactic acid bacteria strains isolated from autochtonous cheeses of Sjenica were researched. In those products, where starters were not added fermentation occurs as a result of natural flora present in the surrounding environment. Forty thermophilic, mesophilic and citrat+ LAB strains were isolated by selective mediums (MRS agar, LM17 agar and LDC agar) from 5 samples of Sjenica-cheese. These strains were exposed to the further analysis and indetification. After examination by Gram test and catalase test, 23 strains of LAB, were selected for further analysis. On the basis of lactose fermentation manner and acid production in 1% reconstituted skim milk, only 6 strains were selected. Determination of theese strains by API 50 CHL and Rapid ID 32 Strep tests, showed that 2 strains belong to the Lactococcus lactis ssp. lactis, 1 strain to the Lactococcus lactis ssp. cremoris, 1 strain to the Lactococcus lactis ssp. lactis bivar. diacetylactis and 2 strains to the Lactobacillus para. paracasei.U radu su izolovani i karakterisani sojevi bakterija mlečne kiseline izdvojeni iz sjeničkog sira, proizvedenog autohtonom tehnologijom, bez dodavanja starter kultura. Iz pet uzoraka sjeničkog sira izvršena je izolacija 40 termofilnih, mezofilnih i citrat+ sojeva BMK na odgovarajućim selektivnim podlogama (MRS agar, LM17 agar i LDC agar). Ovi sojevi su dalje podvrgnuti ispitivanju na Gram reakciju i katalaza test, posle čega je izabrano 23 soja za dalja ispitivanja. Na osnovu načina fermentacije laktoze i acidogene sposonosti praćene u 1% rekonstituisanom obranom mleku selekcionisano je samo šest sojeva. Determinacijom ovih sojeva pomoću API CHL 50 i Rapid ID 32 Strep testa, pokazalo se da dva soja pripadaju Lactococcus lactis ssp. lactis, jedan soj Lactococcus lactis ssp. cremoris jedan soj Lactococcus lactis ssp. lactis bivar. diacetylactis i dva soja Lactobacillus para. paracasei vrsti
Kinetics of nanocrystalline phase transformations in spray pyrolysed ZnO particles
The thermal behavior of ZnO powder obtained by ultrasonic spray pyrolysis of nitrate solution (c=0.8mol/dm3, D0=2.695µm, Tmax=6000C, FG=1.2dm3/min) was investigated using non-isothermal differential scanning calorimetry (DSC, heating rates 5, 10, 15, 20O/min). The exothermic heat effects at the temperature range from 350 to 5000C were linked to particles structural data obtained by XRD, SEM and TEM analysis. Produced particles are characterized by uniform submicronic size (D=800nm, BET=4.94m2/g), high phase purity and granular or circular “open” surface due to the presence of primary crystallites (d= 20nm). Observed structural changes during heating of this powder were attributed to simultaneous processes of nucleation and growth of primary crystallites inside the produced particles
Mechanochemical synthesis of bismuth ferrite
A powder mixture of Bi2O3 and Fe2O3 was mechanically treated in a planetary ball mill in an air from 30 to 720 minutes. It was shown that the mechanochemical formation of BiFeO3 (BFO) phase was initiated after 60 min and its amount increased gradually with increasing milling time. A detailed XRPD structural analysis is realized by Rietveld’s structure refinement method. The resulting lattice parameters, relative phase abundances, crystallite sizes and crystal lattice microstrains were determined as a function of milling time. Microstructural analysis showed a little difference in morphology of obtained powders. The primary particles, irregular in shape and smaller than 400 nm are observed clearly, although they have assembled together to form agglomerates with varying size and morphology. Dense BFO ceramics were prepared by conventional solid-state reaction at the temperature of 810ºC for 1h followed immediately by quenching process. [Projekat Ministarstva nauke Republike Srbije, br. III45007: Zero- to Three-Dimensional Nanostructures for Application in Electronics and Renewable Energy Sources: Synthesis, Characterization and Processin
The synthesis: Structure relationship in the ZnO-Cr2O3 system
In this work the development of the spinel phase in the ZnO-Cr2O3 system was discussed from the viewpoint of the synthesis-structure relationship. The nanostructure evolution in particles obtained either via solution-based (spray pyrolysis) or solid-state (mechanical activation) synthesis procedures were investigated by XRD analysis. A detailed structural analysis of the spinel phase lattice parameters, average primary crystallite sizes and micro strains were performed in accordance with a procedure based on the Koalariet-Xfit program. Due to the importance of spinel-phase cat ion distribution for chemical and physical properties, a study of the site occupation factors, i.e. changes in the stoichiometric, of ZnCr2O4 spinals was undertaken. The calculation based on atomistic methods for the description of both perfect and defect spinel ZnCr2O4 crystal lattices has been applied and the presence of individual structural defects was determined
Feeding habits and helminth parasites of sardine (S. pilchardus) and anchovy (E. encrasicolus) in the Adriatic Sea
We examined the stomach contents of two of the most economically and ecologically important small pelagic fish species, the sardine, Sardina pilchardus and the anchovy, Engraulis encrasicolus, obtained monthly from commercial purse-seine catches operating on Croatian fishing grounds during a one-year period (January–December, 2011). Both species generally showed a similar diet, with copepod and decapod larvae as dominant prey groups. The composition of anchovy and sardine stomach contents was not size- or sex-related, but throughout the year, a significant difference in diet composition was observed for each species as well as between species. Two gastrointerstinal helminths; the digenean Parahemiurus merus and nematode Hysterothylacium aduncum, were recorded during the stomach content analysis. Differences in population dynamics between the two parasites are congruent with differences in the prey composition of sardine and anchovy, reflecting fine-tuned interactions in the trophic web between parasites and intermediate or paratenic hosts included in the sardine and anchovy diet
Hydrographic conditions driving sardine and anchovy populations in a land-locked sea
The aim of this paper is to establish a relationship between long-term variability in sardine and anchovy populations in the Adriatic Sea and ocean dynamics and processes that occur over interannual and decadal timescales in the Adriatic-Ionian basin. Basis for such analysis are annual time series of sardine and anchovy landings and recruits at age 0 and annual time series of environmental parameters observed at a representative Adriatic station between 1975 and 2010. Pearson correlations and robust Dynamic Factor Analysis (DFA) were applied to quantify the connections between fisheries and environmental parameters. Variations and trends in fisheries series were best explained by changes in near-bottom temperature and salinity, being an appropriate proxy for tracking changes in water masses' dynamics and hydrographic conditions in the basin. It seems that a prolonged period of decreasing sardine population was characterized by low oxygen availability and environmental conditions in the deep Adriatic waters, triggered by an extraordinary basin-wide event called the Eastern Mediterranean Transient. A collapse in anchovy population has been observed after an exceptional cooling event followed by dense water formation
Kinetics of heavy metal sorption on macroporous vinylpyridine based copolymer
Sorption of copper, nickel and cobalt on macroporous crosslinked copolymer of 4- vinylpyridine and ethylene glycol dimethacrylate, PVPE, was studied. The kinetics models (pseudo-first and pseudo-second order equations) were applied to the data obtained from batch sorption experiments at room temperature. The sorption of heavy metals was found to proceed according to pseudo-second order kinetics.Physical chemistry 2006 : 8th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 26-29 September 200
3-Anilino-1-ferrocenylpropan-1-one
In the title ferrocene derivative, [Fe(C5H5)(C14H14NO)], the dihedral angle between the mean planes of the phenyl ring and the substituted cyclopentadienyl ring is 84.4 (1)°. The molecules are connected into centrosymmetric dimers via N—H⋯O hydrogen bonds. In addition, C—H⋯O and C—H⋯N contacts stabilize the crystal packing
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