Humus composition of rendzina soils in different environmental conditions of Serbia

This paper shows organic matter composition (humic acids, fulvic acids, humins) and fractions of humic (free and bounded with mobile R2O3 (HAI), bounded with Ca (HA2), and bounded with clay and stabile R2O3 (HA3)), and fulvo acids (free and bounded with mobile R2O3), bounded with HA1 bounded with HA2, and bounded with HA3), in Rendzina soils on different altitudes (151-1210 m), landforms (hilltop, flat or very gentle slope; foot slope, very gentle slope, south, southwest; slope 45-80 degrees, south, southeast, southwest; slope 20-60 degrees, north, northwest, northeast), and regions (Srem, west, central, east and southeast Serbia). Differences in temperature and water regimes of Rendzinas on various altitudes are not so prominent to have a significant impact on organic matter composition. Landform has more significant impact, with average higher content of HA on slopes, and FA on flat positions, which could be attributed to reduced wetting of soils on slopes. Exposition had no significant impact on humus composition. Differences in soil moisture among regions are more pronounced than differences in soil temperature. Differences in soil organic matter composition among Rendzinas from various regions are small and do not follow pattern of humidity change. Still, organic matter of Rendzina from most humid western region has the least favourable HA/FA ratio, while at the driest east and southeast regions content of humin is the greatest

Influence of environmental conditions on carbon and nitrogen content in Serbian rendzina soils

Organic matter in Serbian Rendzina soils dependence on altitude and geographic regions was investigated. There was no regular dynamics of carbon and nitrogen content nor in C/N ratio, probably because of slight climatic variation among altitudes and regions, thus negligible differences in vegetation, organic litter and decomposition dynamics. Predicted climatic changes, uneven for regions, will exert a complex influence on soil C and N storage. These results should be used as a base for future monitoring of C and N content in Serbian Rendzina soils and their dependence on climate

Humic acids optical properties of rendzina soils in diverse environmental conditions of Serbia

This study examined the impact of climate, altitude and landforms on humic acids (HA) optical properties (E-4/E-6, Delta logK, RF indexes) in Serbian Rendzina soils. HA humification degree of calcareous and decarbonated Rendzinas under natural vegetation (forest and grassland, separately) decreased with altitude increasing. This particular rule was not manifested in arable Rendzinas. HA humification degree in Rendzinas on flat positions (hilltop and footslope) is significantly higher than in Rendzinas on slope sides. Humification degree of HA is the highest in Rendzinas in eastern Serbia (in the vicinity of Negotin), followed by central Serbia (Sumadija) and Srem, southeast and finally, southeast and southwest Serbia. With respect to the climate change foreseen for the end of this century, i.e. increase of precipitation and temperature variance among the regions in Serbia, also an increase in variance of quality of humic acids in Rendzinas on different altitudes and regions can be expected

Uticaj procesa izluživanja i načina korišćenja rendzina na stepen humificiranosti huminskih kiselina

The humification degrees of humic acids extracted from calcareous and decarbonated Rendzinas under different land use were characterized upon their optical properties, to evaluate the influence of carbonate leaching (decarbonation) and different land uses. Decarbonation influenced the humification degree of humic acids positively. Base leaching and acidification of decarbonated Rendzinas led to a decrease in humification degree of humic acids. In calcareous Rendzinas, the humification degree of humic acids was in descending order: grassland>arable land>forest land, and in decarbonated Rendzinas: arable land>grassland>forest land. The humification degree of humic acids was higher in the calcareous forest and grassland Rendzinas compared to decarbonated Rendzinas, analogously in decarbonated arable land compared to calcareous arable land Rendzinas. Differences in the humification degree of humic acids among various land uses that emerged between calcareous and decarbonated Rendzinas indicate the dominant influence of soil chemical characteristics (carbonate content and pH value) compared with the quantity and quality of the organic litter input.Prema domaćoj klasifikaciji, rendzine su zemljišta sa moličnim A horizontom koji postepeno prelazi u rastresiti karbonatni C horizont. Primarno su karbonatna, i njihova evolucija teče u pravcu izluživanja pa zatim posmeđivanja. Najčešće su pod prirodnom šumskom i travnom vegetacijom, manji deo njih se obraduje. U ovom radu su ispitivane optičke osobine huminskih kiselina zemljišta tipa rendzina, a istraživanja su imala za cilj praćenje posledica izluživanja i promene načina korišćenja ovog tipa zemljišta u Srbiji na stepen humificiranosti huminskih kiselina. Priprema rastvora huminskih kiselina za VIS spektroskopiju izvedena je metodom Kononove. Karakterizacija optičkih osobina huminskih kiselina je data preko optičkih indeksa: E4/E6, ΔlogA i RF. Rezultati su obrađeni u programu StatSoft, Inc. Statistica, Version 8. Proces izluživanja je pozitivno uticao na stepen humificiranosti huminskih kiselina u rendzinama (najveći je pri neutralnoj reakciji). Dalja debazifikacija i acidifikacija izluženih rendzina uticala je negativno, odnosno dovela do smanjenja stepena humificiranosti huminskih kiselina. Stepen humificiranosti huminskih kiselina u karbonatnim rendzinama se kretao travnjak>njiva>šuma, a u izluženim rendzinama njiva>travnjak>šuma. Huminske kiseline karbonatnih rendzina pod šumom i travnjakom su imale veći stepen humificiranosti u poredenju sa izluženim rendzinama pod šumom i travnjakom. U izluženim rendzinama pod njivom stepen humificiranosti huminskih kiselina je bio veći nego u karbonatnim rendzinama pod njivom. Razlike u stepenu humificiranosti huminskih kiselina prema načinu korišćenja koje su se pojavile između karbonatnih i izluženih rendzina ukazuju na dominantan uticaj hemijskih karakteristika zemljišta na osobine huminskih kiselina u poredenju sa količinom i kvalitetom organskih ostataka koji dospevaju u zemljište

Microstructural and Electrical Properties of Cordierite-based Ceramics Obtained After Two-step Sintering Technique

Cordierite-based ceramic materials are attracting much interest for their various applications in industry, for manufacturing multilayer circuit boards, catalytic converters, filters, thermal insulation, kiln furniture, components of portable electronic devices, etc. In order to reduce production costs and modify cordierite-based materials, mechanical activation can be used. In this study, microstructural and electrical properties of mechanically activated MgO-Al2O3-SiO2 system have been analyzed. The mixtures of MgO-Al2O3-SiO2 powders were mechanically activated in a planetary ball mill for the time periods from 0 to 160 min. Morphological investigations have been performed on the obtained powders. The effects of activation and two-step sintering process on microstructure were investigated by scanning electron microscopy (SEM). Electrical measurements showed variations of the dielectric constant (epsilon(r)) and loss tangent (tan delta) as a function of time of mechanical treatment

MODELING OF DEFECTS DETECTION BY ANALYZING THERMAL IMAGES

In this paper a contactless method for the detection of an object’s defect by applying the thermovision camera is proposed and implemented. The thermal image processing is realised in two perpendicular directions and the analysis of the results is presented. An advantage of the proposed method is a simple and efficient application of the standard techniques, which are not specially designed for thermal image processing. By comparing the analysis of results obtained by this method with those obtained by already known methods, the applicability of this method could be confirmed. Using the powerful software packages and applications the thermovision images are being transformed into digital records that can be processed on personal computers. The conducted experiments show that this contactless method is very efficient in the detection of the defects in forms of cavities and damages caused by overload or by material fatigue

Uticaj načina korišćenja na vodne karakteristike planosola (južna Mačva i Pocerina, Srbija)

Water holding capacities and saturated hydraulic conductivity of Planosols in south Mačva and Pocerina (Serbia) were compared to assess how different types of land use (forest, arable and grassland) influence soils endangered by stagnating water. These changes came from decrease of total porosity and changes in pores size distribution in arable and grass land compared to forest land. Changes of water characteristics of arable and grassland Planosols compared to forest Planosols were statistically most significant in illuvial horizon Btg (absence of root network and fauna activity). It is important to emphasize: (i) surface A horizon of arable and grass land compared to forest showed insignificant increase of plant available water and significant decrease of saturated hydraulic conductivity (ii) significant decrease of saturation and macro porosity increased the risk of oxygen deficiency in Planosols in wet periods of year in this order: arable land > grassland > forest.Cilj rada je utvrđivanje promena u vodnim kapacitetima i vodopropusnosti planosola na području Mačve i Pocerine zbog pretvaranja šuma u travnjake i njive. Promena načina korišćenja značajno je uticala na vodne kapacitete, ali ne i na vodopropusnost. Generalno u poređenju sa šumama, u njivama i travnjacima je došlo do smanjenja MVK i povećanja vrednosti PVK, LVK i VV. Navedene promene su posledica smanjenja ukupne poroznosti i promene diferencijalne poroznosti. Promene u njivama i travnjacima su najznačajnije u Btg horizontu (odustvo korenovog sistema i faune), zatim u A horizontu (smanjenje korenovog sistema, aktivnosti faune i sadržaja humusa), a najmanje u Eg horizontu (manja promena poroznosti zbog nestrukturnosti). Sa agroekološkog aspekta je važno istaći da u A horizontu njiva i travnjaka u poređenju sa šumama povećanje KPV i smanjenje SHC nije značajno; značajno smanjenje MVK i makroporoznosti povećava rizik od nedostatka kiseonika u vlažnom delu godine ovim redom: njive > travnjaci > šume

Antioxidant and Anticancer Properties of Leaf and Fruit Extracts of the Wild Raspberry (Rubus idaeus L.)

In this study the leaves and fruits of wild raspberry (Rubus idaeus L.) populations from the central Balkan region were examined to determine the level of secondary metabolites and related antioxidant activity, as well as biological activity, upon existing ethnobotanical evidence, primarily linked to gastrointestinal disorders. The values obtained for total phenols ranged from 59.68 to 96.83 mg GA g(-1) and 24.29 to 38.71 mg GA g(-1) in leaf and fruit extracts, respectively. The highest values of tannins and anthocyanins were determined for leaf extracts from a population of east Serbia at a level of 1.27 mg mL(-1) and 9.00 mg mL(-1). Antioxidant activity was evaluated by measuring the scavenging capacity of the extracts on DPPH. Higher antioxidant activity was detected in the leaf extracts than in the fruit extracts. Leaf and fruit extract were the most effective against Escherichia coli (ATCC 8739). Anticancer activity was studied on a human colorectal cancer cell line HCT-116. Leaf extracts exhibited anticancer activity with IC50/24 h 162.38 mu g mL(-1) and IC50/48 h 95.69 mu g mL(-1). Wild raspberry leaf and fruit extracts contain numerous secondary metabolites providing marked antioxidant, antimicrobial and anticancer activity

Kvalitativna svojstva kopitara gajenih u Centralnoj Srbiji

The paper presents and analyzes the results of the measures selection of equidae (horse and donkey) in Central Serbia, conducted in the three-year period (2007th - 2009th years). In that period, based on exterior (phenotype), and production - reproductive indicators, carried out the evaluation and grading a number of heads equidae. Based on research conducted, it can be seen more general situation of the growing equidae in central Serbia, or changes the numerical situation for years, racial composition, and especially the quality of available animals, i.e. age of animals that are used primarily in reproduction and sports, and much less labor in the production of meat and milk of special quality. Results of research carried out indicate that it is necessary devote more attention to quality and racial composition of the throat or throat selection depending on their use, then the direction of breeding, sport animals ready for competition, diet and way of preparation (training) of sport horses, and therefore and the introduction of stricter application of appropriate methods selection the growing equidae.U radu su prikazani i analizirani rezultati selekcijskih mera kod kopitara (konja i magaraca) u Centralnoj Srbiji, sprovedenih u trogodišnjem periodu (2007 - 2009. godina). U navedenom periodu, na osnovu eksterijernih (fenotipskih) i proizvodno-reproduktivnih pokazatelja, izvršeno je ocenjivanje i klasiranje određenog broja grla kopitara. Na osnovu sprovedenih istraživanja, može se detaljnije sagledati opšte stanje pri gajenju kopitara u Centralnoj Srbiji, odnosno promena brojnog stanja po godinama, rasni sastav, a pre svega kvalitet raspoloživog broja grla, tj. starost grla koja se koriste prvenstveno u reprodukciji i sportu, a znatno manje kao radna snaga i u proizvodnji mesa i mleka posebnog kvaliteta. Rezultati sprovedenih istraživanja ukazuju na to da je potrebno posvetiti veću pažnju kvalitetu i rasnom sastavu grla, odnosno odabiru grla u zavisnosti od njihove upotrebe, zatim pravcu odgajivanja, spremnosti sportskih grla za takmičenje, ishrani i načinu pripreme (treniranja) sportskih konja, a samim tim uvođenje i strožiju primenu odgovarajućih selekcijskih metoda pri gajenju kopitara

‐sitosterol and gentisic acid loaded 1,2‐dipalmitoyl‐sn‐glycero‐3‐phosphocholine liposomal particles

The aim of the present study was the examination of the impact of -sitosterol andgentisic acid on the characteristics of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine(DPPC) liposomal particles: (a) bilayer permeability (fluorescence spectroscopy),(b) particle size, polydispersity index (PDI) and zeta potential (photon correlationspectroscopy) and (c) thermal properties (differential scanning calorimetry). -sitosterol induced the increase of liposomal bilayer rigidity, due to rearranging ofthe phospholipid chains, while gentisic acid enhanced the membrane fluidity, dueto the reduced orderliness and the increase of phospholipid dynamics. The inclusionof -sitosterol in liposomes caused a significant increase in particle diameterand PDI, while the encapsulation of gentisic acid did not have influence on particlesize distribution. Apart from that, the presence of -sitosterol resulted in thesignificant zeta potential increase, and thus a better stability of liposomal spheres(in the absence and in the presence of gentisic acid). -sitosterol decreased maintransition temperature (Tm) and phase transition enthalpy (H), and caused thedisappearance of the pre-transition peak as well, whereas the presence of gentisicacid produced a slight decrease in Tm and increase of H. Therefore, gentisic acidhad more favourable, stabilizing interactions with phospholipids than -sitosterol.Thus, it can be concluded that -sitosterol is located in the bilayer interior betweenphospholipids acyl chains, and gentisic acid is incorporated near the outer leaflet ofthe phospholipid membrane, next to the polar head groups. -sitosterol and gentisicacid loaded DPPC liposomal particles have a potential to be used in food andpharmaceutical products, due to the important individual and possible synergisticbeneficial health properties of -sitosterol and gentisic acid