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Sunflower (Helianthus annuus L.) is one of the most important oilseed crops throughout the world, and in Serbia it is grown on about 160,000 to 210,000 ha. Alternaria alternata (Fr.) Keissler has been detected as the most frequent seed-borne pathogen, able to infect a wide variety of plant species in different countries. During a routine seed quality control and seed health testing analysis of sunflower seed in 2018-2019, according to ISTA Rules, Alternaria spp. infection was observed on an average of 18%. The aim of this study was the isolation and identification of Alternaria spp. based on their morphological characteristics and molecular analyses. Isolation of the pathogen was carried out by transferring infected seeds onto a potato dextrose agar (PDA), and subsequent incubation at 25°C. Seven days later, 21 isolates formed circular, smooth, grey to brownish-black colonies, with concentric zones of very intensive sporulation. Conidiophores were branched, solitary or in small groups, brown to olivaceous brown, ranging from 128 to 232 µm. All isolates were subcultured onto a PDA using a single spore technique.

The sunflower (Helianthus annuus L.) is one of the most important oil crops in the world and the most important cultivated oil crop in Serbia, where it is grown on about 160,000 to 210,000 ha and the seed yield ranging from 1.7 to 2.3 t/ha. Several seed-borne fungi including species of Alternaria, Aspergillus, Cladosporium, Drechslera, Epicoccum, Fusarium and Penicillium, have been reported from sunflower seeds and could cause different levels of losses in its production. During the routine seed quality control and seed health testing analysis of sunflower, according to ISTA Rules, Cladosporium spp. infection was observed on an average of 5%. The aim of this study was the isolation and identification of Cladosporium spp. based on their morphological characteristics and molecular analyses. Isolation of the pathogen was carried out by transferring infected seeds onto a potato dextrose agar (PDA), and incubated for 5 days at 25 °C. Cladosporium-like colonies were transferred onto fresh PDA and water agar (WA, 17 g agar and 1 liter of distilled H2O) to obtain monosporial isolates. Seven days later, five isolates formed grey-greyish brown, velvet-like colony with apically and laterally branched conidiophores. Margin of the colony was white to grey-olivaceous. Conidias were mostly globose to subglobose, 3-4.5 µm in diameter, mild to dark olivaceous brown.

The objective of this study was to examine the effects of different priming treatments on seed quality and initial growth and development of garden pea. For this purpose, three garden pea cultivars, developed at the Institute of Field and Vegetable crops, Novi Sad were examined. The laboratory experiment was conducted under optimal conditions. Seeds were primed in water (hydropriming), 0.5% KNO3 solution, and -0.49 MPa PEG solution for 24 hours; non-primed seeds were controls. The results showed that the percentage of germination, shoot and root length, and mean germination rate significantly increased after the tested priming treatments, while the percentage of abnormal seedlings and mean germination time were significantly decreased after the priming treatments compared to the control. The increase of fresh and dry seedling biomass was significant only in cv.1 and cv.2. Despite the genetic diversity of pea cultivars, the results indicated that the examined seed priming treatments enhanced seed quality and vigour of garden pea cultivars., Cilj ovog istraživanja bio je da se ispitaju efekti različitih tretmana prajminga na kvalitet semena i početni rast i razvoj povrtarskog graška. U tu svrhu ispitane su tri sorte povrtarskog graška stvorene u Institutu za ratarstvo i povrtarstvo u Novom Sadu. Laboratorijski ogled je izveden u optimalnim uslovima. Seme je potapano u vodu (hidroprajming), 0,5% rastvor KNO3 i -0,49 MPa rastvor PEG tokom 24 sata; netretirano seme je bilo kontrola. Rezultati su pokazali da su se procenat klijanja, dužina nadzemnog dela i korena izdanaka, kao i srednja stopa klijanja značajno povećali u ispitivanim tretmanima prajminga, dok su se procenat atipičnih izdanaka i srednje vreme klijanja značajno smanjili u tretmanima prajminga u poređenju sa kontrolom. Povećanje sveže i suve biomase izdanaka bilo je značajno samo kod sorti cv.1 i cv.2. Uprkos genetskoj raznolikosti sorti graška, ovi rezultati su pokazali da su ispitivani tretmani prajminga semena efikasne metode u smislu povećanja kvaliteta i vigora semena sorti povrtarskog graška.

In order to achieve widespread application of fuel cell technology, the development of an efficient and economical catalyst is a crucial step. Reducing the diameter of catalyst particles, producing particles with a specific orientation surface, and alloying noble metals with less expensive metals are possible approaches to improve catalyst performance. This study will be focused on novel ways for creating PtSnZn catalysts that are more effective for the anodic reactions in fuel cell such are methanol, ethanol and formic acid oxidation reactions. PtZn and PtSnZn nanoparticles were produced using the microwave assisted polyol method and were supported on high surface area carbon Vulcan XC-72R material. The electrochemical behavior of synthesized catalysts was investigated utilizing the cyclic voltammetry, chronoamperometric technique, and electro-oxidation of adsorbed CO. To determine the catalyst's physicochemical characteristics, X-ray diffraction (XRD), transmission electron microscopy analysis (TEM), and thermogravimetric analysis (TGA) were used. High catalytic activity of the PtSnZn/C catalysts was achieved thanks to the benefits of microwave synthesis and carefully adjusted metal alloying.

PtZn katalizator deponovan na ugljenik razvijene površine Vulcan XC-72R sintetizovan je poliol metodom uz pomoć mikrotalasne pećnice i testiran za reakciju elektrooksidacije metanola, etanola i mravlje kiseline u sumpornoj kiselini. Poređenje stabilnosti PtZn/C katalizatora za reakciju elektrooksidacije metanola, etanola i mravlje kiseline dobijeno je produženim cikliziranjem. Fizičkohemijska svojstva dobijenih katalizatora su okarakterisana transmisijskom elektronskom mikroskopijom (TEM), termogravimetrijskom (TGA) analizom i energetsko disperzivnom spektroskopijom (EDS). Prema TEM analizi, PtZn/C katalizator ima male čestice prilično slične veličine između 1 i 2 nm. TGA analiza je pokazala 27,68 tež. % metala za PtZn/C katalizator. Hemijski sastav PtZn/C katalizatora je pokazao da je odnos Pt:Zn u katalizatoru 87 tež.% : 13 tež.%. Dodavanje Zn u Pt značajno poboljšava aktivnost za oksidaciju metanola i etanola u poređenju sa Pt/C referentnim katalizatorom. Testovi stabilnosti su potvrdili da su PtZn/C katalizatori najstabilniji za reakciju elektrooksidacije metanola. Uočena visoka katalitička aktivnost i dobra stabilnost u reakciji oksidacije metanola sintetizovanog katalizatora mogu se pripisati veoma efikasnoj mikrotalasnoj sintezi i dobro izbalansiranom sadržaju Zn kao legirajućeg metala., PtZn catalyst material deposited on high surface area carbon Vulcan XC-72R was synthesized by microwave-assisted polyol method and tested for methanol, ethanol and formic acid electrooxidation reaction in sulphuric acid. The comparison of the stability behaviour of the PtZn/C catalyst for the methanol, ethanol and formic acid electrooxidation reaction were obtained from prolonged cycling. Physicochemical properties of obtained catalysts were characterized by transmission electron microscopy (TEM), thermogravimetric (TGA) analysis and energy dispersive spectroscopy (EDS). According to TEM analysis PtZn/C catalyst have small particles of rather similar size between 1 and 2 nm. TGA analysis revealed 27.68 wt. % of metals in PtZn/C catalyst powder. The chemical composition of the PtZn/C catalyst was showed that the Pt:Zn ratio for the PtZn/C catalyst is 87 wt.% : 13wt.%. Addition of Zn to Pt significantly improves methanol and ethanol oxidation activity in comparison to Pt/C benchmark catalyst. Long term stability tests confirmed that PtZn/C catalysts are notably less poisoned for the methanol electroxidation reaction. The observed high catalytic activity and good stability in the methanol oxidation reaction of synthesized catalyst can be ascribed to the very efficient microwave synthesis and well-balanced content of Zn as alloying metal.

Procesi nukleacije i rasta dendrita kalaja iz alkalnog hidroksidnog elektrolita su istraženi hronoamperometrijom i skenirajućom elektronskom mikroskopskom (SEM) analizom taloga potenciostatski elektrohemijski istaloženih na selektivnim katodnim potencijalima. Za određivanje tipa nukleacije korišćen je model Šarifkera i Hilsa (SH) zasnovan na trodimenzionalnoj nukleaciji sa difuziono kontrolisanim rastom. Bez obzira na primenjeni katodni potencijal, dobijene bezdimenzionalne zavisnosti su bile niže od teorijskih predviđanja za progresivni tip nukleacije. Sa druge strane, morfologija dendrita kalaja je snažno zavisila od primenjenog katodnog potencijala, te igličasti ili dendriti nalik paprati su bili formirani potenciostatskim režimom elektrohemijskog taloženja. Na osnovu morfološke analize Sn dendrita elektrohemijski istaloženih različitim količinama elektriciteta, zaključeno je da nukleacija Sn iz ispitivanog elektrolita ipak sledi progresivni tip, i da se odstupanje od teorijskih predviđanja za ovaj tip može pripisati upotrebi kompleksnog elektrolita za elektrohemijsko taloženje kalaja., The processes of nucleation and growth of tin dendrites from alkaline hydroxide electrolyte have been investigated by chronoamperometry and by the scanning electron microscopic (SEM) analysis of the deposits potentiostatically electrodeposited at the selected cathodic potentials. The Scharifker and Hills (SH) model based on three dimensional nucleation with diffusion controlled growth was used for a determination of a nucleation type. Irrespective of the applied cathodic potential, the obtained dimensionless dependencies were lower than the theoretical predictions for the progressive type of nucleation. On the other hand, morphology of Sn dendrites strongly depended on the applied cathodic potential, and either the needle-like or the fern-like dendrites were formed by the potentiostatic regime of electrodeposition. On the basis of the morphological analysis of Sn dendrites electrodeposited with various amounts of the electricity, it is concluded that nucleation of Sn from the examined electrolyte still follows the progressive type, and that the deviation of the theoretical predictions for this type can be attributed to use of complex electrolyte for Sn electrodeposition.

This work highlights a simple and efficient approach for the development of PtZn catalyst materials with tunable content of Zn. Nanoparticles of PtZn deposited on high surface area carbon Vulcan XC-72R material were synthesized by microwave-assisted polyol method, giving control over the size and dispersion of nanoparticles. Cyclic voltammetry and electrooxidation of adsorbed CO were used to investigate the electrochemical behavior of synthesized catalysts: PtZn/C (90:10); PtZn/C (85:15) and PtZn/C (75:25). It was found that PtZn/C catalysts have high electrocatalytic performance in methanol oxidation reactions. In comparison to the corresponding catalyst with the different Zn loading, it was concluded that PtZn (90:10)/C catalyst had better activity compared to PtZn/C (85:15) and PtZn/C (75:25) catalysts. The observed high catalytic activity in the methanol oxidation reaction of synthesized catalysts can be ascribed to the very efficient microwave synthesis and well-balanced content of Zn as alloying metal., Ovaj rad predstavlja jednostavan i efikasan pristup za razvoj PtZn katalizatora sa različitim sadržajem Zn. Nanočestice PtZn istaložene na ugljeničnom materijalu Vulcan XC-72R velike površine, sintetisane su poliol metodom pomoću mikrotalasne pećnice, dajući kontrolu nad veličinom i disperzijom nanočestica. Za ispitivanje elektrohemijskog ponašanja sintetisanih katalizatora PtZn/C (90:10); PtZn/C (85:15) i PtZn/C (75:25) korišćeni su ciklična voltametrija i elektrooksidacija adsorbovanog CO. Utvrđeno je da PtZn/C katalizatori imaju visoke elektrokatalitičke performanse u reakcijama oksidacije metanola. Poređenjem katalizatora sa različitim sadržajem Zn, zaključeno je da PtZn/C (90:10) katalizator ima bolju aktivnost u odnosu na PtZn (85:15) i PtZn (75:25) katalizatore. Uočena visoka katalitička aktivnost sintetisanih katalizatora u reakciji oksidacije metanola može se pripisati veoma efikasnoj mikrotalasnoj sintezi i dobro izbalansiranom dodavanju Zn kao legirajućeg metala sa različitim sadržajem u PtZn/C katalizatorima.

A wide occurrence of wilt and rot caused by Fusarium species has been observed in the last few years in many vegetable-growing areas in the Republic of Serbia. Symptoms of rot and wilt of celery, garlic, and onion were noticed and after determination, Fusarium spp. was identified as the main causal agent of the disease. Most of the Fusarium species that cause disease on vegetable crops (garlic, onion, celery) overwinter in soil debris and soil. This study was conducted to isolate and identify Fusarium from soil samples by conventional and molecular methods. Soil samples were taken under the diseased plant, and 25 samples were collected in order to perform isolation of Fusarium species that cause rot and wilt during production.

Many reports emphasized the role of calcium fertilizers in tomato production as a key nutrient for enhancing productivity and its positive relationship with quality attributes. The application of nanotechnology in modern agriculture has gained significant attention recently due to the recent discovery of nanochemicals as potentially effective pesticides, fertilizers, and promising agents for plant growth. Recent scientific data indicated the positive effects of calcium nanoparticles (NPs) on plant growth and development, and subsequent yield and yield quality of many crops. However, there is a lack of information on their effect on tomato seed quality and initial plant growth.

Nanopriming is a newly developed seed technology that improves seed germination, initial plant growth, and crop yield by enabling plants to withstand a variety of abiotic stresses. The objective of this study was to evaluate the effectiveness of comprehensive metal-based (Co, Mn, Cu, Fe, Zn, Mo, and Se) nanopriming as compared to hydro- and non-primed seeds of three different pea cultivars in a germination test. Seed priming with nanoparticles (NPs) improved field pea quality via significant increase in germination energy (cv. E-244), final germination (cv. E-244, cv. Dukat), shoot length (cv. E-244, cv. Partner), root length (cv. E-244, cv. Dukat, cv. Partner), fresh shoot weight (cv. Partner), dry shoot weight (cv. Partner), seedling vigor index (cv. E-244, cv. Partner), and chlorophyll content (cv. Dukat, cv. Partner), as compared to both hydropriming and the control. Moreover, nanopriming led to significant improvements in shoot length, fresh shoot length, dry shoot length, seedling vigor index (cv. Dukat), and dry root weight (cv. E-244) as compared to the control only. In general, the highest effect on the examined parameters was achieved by nanopriming, indicating that this treatment may be utilized to raise field pea quality performance. To optimize the method, it is necessary to conduct extensive laboratory and field trials.

Background: This study was carried out for an understanding of the antioxidant mechanisms of field pea varieties under osmotic stress conditions caused by a lack of water. The activities of antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APx) and glutathione reductase (GR) were examined and analyzed. The gene expression levels of Cu/Zn SOD, cAPx and GR genes were also examined. Methods: Osmotic stress was stimulated using PEG 6000 with the osmotic potential of -0.1 MPa in 10 days old plant seedlings. The activity of the antioxidant enzymes was measured in the shoots and roots of pea seedlings. The gene expression levels of genes coding antioxidative enzymes were examined by the reverse transcription polymerase chain reaction (RT-PCR) technique. Arabidopsis 18S rRNA was used as endogenous control. Result: Osmotic stress changed the activities of antioxidant enzymes in the shoots and roots of pea seedlings. Varieties more tolerant to osmotic stress showed a significant increase in antioxidant activities in shoots and roots, while sensitive varieties showed a significant decrease. The results of the analysis of the expression of genes, coding for antioxidant enzymes, showed that the reaction of the tested cultivars to ROS was the result of increased expression of the tested genes in tolerant cultivars, i.e. decreased expression in sensitive cultivars.

Realizovana sorta paštrnaka NS Lala.

Salinity is one of the greatest challenges of successful agricultural production worldwide. However, seed priming might be efficient practice for enhancing seed germination and initial plant growth and development. This experiment was undertaken with the aim of assessing the impact of different priming methods on seed quality parameters and early growth of garden pea (Pisum sativum L.) cultivars under salinity stress. Pea seeds of three different cultivars were primed with water (hydropriming), KNO3 solution (0.5%), and PEG 6000 solution (-0.5 MPa) for 24h in the dark. Unprimed and primed seeds were germinated between filter papers saturated with 120 mM NaCl using the germination test. The results clearly showed that the examined parameters of primed pea seeds were substantially greater than the parameters of unprimed seeds under saline stress. Moreover, seed priming with KNO3 and PEG solutions were more effective in improving seed quality and initial growth in garden peas than hydropriming.

Ovo je sorta tikvice Zita priznata od strane Ministarstva poljoprivrede, šumarstva i vodoprivrede Republike Srpske.

Ova studija je fokusirana na pronalaženje novih načina sinteze katalizatora na bazi platine koji pokazuju dobru efikasnost za reakciju oksidacije metanola. Nanočestice PtZn, PtSn i PtSnZn su sintetizovane korišćenjem poliol metode uz pomoć mikrotalasnog zagrevanja i deponovane na ugljeničnu podlogu Vulcan XC-72R. Elektrohemijsko ponašanje sintetizovanih katalizatora je ispitivano korišćenjem ciklične voltametrije i hronoamperometrijske tehnike. Fizičkohemijska svojstva dobijenih katalizatora su okarakterisana transmisionom elektronskom mikroskopijom (TEM), termogravimetrijskom analizom (TGA) i energetsko disperzivnom spektroskopijom (EDS). Prema TEM analizi svi katalizatori imaju male čestice prilično slične veličine između 1 i 3 nm. Dobijeni rezultati su potvrdili uspešnu sintezu katalizatora na bazi Pt. Dodavanje Zn i Sn u Pt katalizator značajno poboljšava aktivnost oksidacije metanola u poređenju sa Pt/C referentnim katalizatorom. Testovi stabilnosti takođe dokazuju slabije trovanje i ukazuju na bolju stabilnost i veću toleranciju na CO intermedijere. Uočena visoka katalitička aktivnost i dobra stabilnost u reakciji oksidacije metanola sintetizovanih katalizatora mogu se pripisati veoma efikasnoj mikrotalasnoj sintezi i dobro izbalansiranom sadržaju Zn i Sn kao legirajućih metala., This study is focused on novel ways for creating Pt alloy catalysts that are more effective for the methanol oxidation reaction. PtZn, PtSn and PtSnZn nanoparticles were produced using the microwave assisted polyol method and were supported on high surface area carbon Vulcan XC-72R material. The electrochemical behaviour of synthesized catalysts was investigated utilizing the cyclic voltammetry and chronoamperometric technique. To determine the catalyst's physicochemical characteristics, transmission electron microscopy analysis (TEM), energy dispersive spectroscopy (EDS) and thermogravimetric analysis (TGA) were used. According to TEM analysis all catalysts have small particles of rather similar size between 1 and 3 nm. The obtained results confirmed the successful synthesis of Pt-based catalyst. Addition of Zn and Sn to Pt significantly improves methanol oxidation activity in comparison to Pt/C benchmark catalyst. Stability tests also prove the lower poisoning and indicate better stability and higher tolerance to CO-like intermediaries. The observed high catalytic activity and good stability in the methanol oxidation reaction of synthesized catalyst can be ascribed to the very efficient microwave synthesis and well-balanced content of Zn and Sn as alloying metal.

This work highlights the potential for the synthesis of new PtSnZn catalysts with enhanced efficiency and durability for methanol oxidation reaction (MOR) in low-temperature fuel cells. In this research, PtZn and PtSnZn nanoparticles deposited on high surface area Vulcan XC-72R Carbon support were created by a microwave-assisted polyol method. The electrochemical performances of synthesized catalysts were analyzed by cyclic voltammetry and by the electrooxidation of adsorbed CO and the chronoamperometric method. The physicochemical properties of obtained catalysts were characterized by transmission electron microscopy (TEM), thermogravimetric (TGA) analysis, energy dispersive spectroscopy (EDS) and by X-ray diffraction (XRD). The obtained findings showed the successful synthesis of platinum-based catalysts. It was established that PtSnZn/C and PtZn/C catalysts have high electrocatalytic performance in methanol oxidation reactions. Catalysts stability tests were obtained by chronoamperometry. Stability tests also confirmed decreased poisoning and indicated improved stability and better tolerance to CO-like intermediate species. According to activity and stability measurements, the PtSnZn/C catalyst possesses the best electrochemical properties for the methanol oxidation reaction. The observed great electrocatalytic activity in the methanol oxidation reaction of synthesized catalysts can be attributed to the beneficial effects of microwave synthesis and the well-balanced addition of alloying metals in PtSnZn/C catalysts.

In this study, the formic acid electrooxidation reaction was studied on a platinum thin film catalyst obtained by deposition on chromium support (Pt/Cr). In an attempt to reduce the proneness of Pt to poisoning species i.e. CO and improve the catalytic performance of Pt/Cr at low potentials in the formic oxidation reaction, the as- prepared catalyst was modified using controlled thermal treatment. The influence of thermal treatment on the electrode surface morphology was monitored using an atomic force microscope (AFM). Thus obtained catalyst was electrochemically characterized with cyclic voltammetry and oxidation of CO monolayer, while the performance of the catalyst was tested in a formic acid oxidation reaction. The improved activity on annealed Pt/Cr system is a consequence of the surface reconstruction of Pt film with predominant (111) orientation. Compared to other facets, the (111) facet selectively favors direct HCOOH oxidation, avoiding Coad poisoning at low potentials. Moreover, the Pt (111) facets offer improved stability of the catalyst compared to the as-prepared polycrystalline film. Finally, the Cr substrate also experiences improved stability after annealing, presumably due to the formation of a protective oxide layer. Thus, with the successful choice of the supporting material and annealing temperature, we were able to create a thin film catalyst with improved activity, selectivity and stability, in contrast with commonly observed activity-stability tradeoff in catalysis.

The electrocatalytic oxidation of small organic molecules, such as methanol, ethanol and formic acid has been extensively studied due to their properties that make them suitable for use in fuel cells. Particularly, the electrochemical oxidation of formic acid has been comprehensively examined as the anodic reaction in direct formic acid fuel cell. The main goal in the development of the catalysts for formic acid oxidation (FAO) is to find the optimal balance between catalytic performance (activity/stability) and the catalyst cost, i.e. quantity of the noble metal used. In the work presented herein, we explored the synergistic effects of the supporting material and annealing temperature on the performance of Pt thin film catalysts for FAO in acidic media. Our results show that compared to the as-prepared Pt films, the annealed (500 oC) films show exceptional activity for FAO reaction on both Pt/Ni and Pt/Cr catalysts, with 5-fold and 15-fold improvement, respectively. The 500 oC annealed Pt/Cr catalyst was found to be the most active, the most selective and the most stable catalyst in our study. A catalyst with the best marks for all three characteristics is a very rare find in electrocatalysis in general.

Polymer electrolyte membrane fuel cells (PEMFCs) are pure electrochemical energy converters that are key components of energy sources for vehicles and for stationary and portable energy suppliers. Searching for a good catalyst for the ethanol oxidation reaction is one of the most significant issues in material science. To increase the economic potential of fuel cell technology, catalyst must be extremely active, stable, and inexpensive. Due to its high catalytic activity, structural and chemical stability, and widespread use in commercial fuel cells, platinum is still the material of choice for making cathodes. Although there is extensive continuing research to reduce the Pt concentration while keeping the high catalytic activity, its high cost remains a barrier to a wider adoption of fuel cell technology.Therefore, the potential for cost reduction lies in the optimization of the catalyst, i.e. obtaining the maximum catalytic efficiency with the lowest possible content of noble metals. The focus of this research will be on novel synthesis techniques for PtSnZn catalysts with better efficiency and durability for the ethanol oxidation reaction. This research demonstrates the potential of studying new PtSnZn catalytic materials as catalysts for the oxidation of ethanol. This study used the microwave assisted polyol technique to create PtZn and PtSnZn nanoparticles supported on high surface area carbon Vulcan XC-72R material. By using cyclic voltammetry, electro-oxidation of adsorbed CO, and the chronoamperometric method, the electrochemical behavior of synthesized catalysts was examined. X-ray diffractometry, transmission electron microscopy analysis and thermogravimetric analysis were applied to obtain the physicochemical properties of the catalyst. The advantages of microwave synthesis and carefully balanced metal alloying in the PtSnZn/C catalysts led to a high catalytic activity of the synthesized catalyst in the ethanol oxidation reaction compared to the Pt/C cata

Pollution caused by the usage of fossil fuels is a consequence of industrialization, urbanization, and technological development, having a huge impact on the environment and human health. Thus, one of the biggest challenges that currently confront not only the scientific community but also humanity is reducing the use of fossil fuels, as well as the production and consumption of energy using renewable energy sources. In the last decades, small organic molecules such as methanol, ethanol and formic acid have attracted attention due to their properties that make them convenient for use in fuel cells. Among other precious metals, Pt is the most investigated as a promising catalyst for the anodic electrooxidation reaction of small organic molecules. However, high price, scarceness and susceptibility to poisoning are some of the limiting factors for the commercial use of pure Pt. There are two ways to mitigate those problems: lower the content of a noble metal present or make the catalyst more active for the particular reaction. To address the first problem nanocatalyst, produced by the deposition of platinum onto high surface area supports were introduced. A far greater challenge is to modify the catalyst to make it not just more active, but more stable as well, for a particular reaction. It is now well known that bimetallic catalysts fulfill these requirements quite well, and currently, they are widely used in many catalytic and electrocatalytic processes. In this study, a thin Pt film was electrochemically deposited on nickel support (Pt/Ni) and afterward subjected to the controlled thermal treatment in an attempt to reduce the proneness of Pt to poisoning species (CO) and therefore improve its catalytic performance at low potentials in the formic oxidation reaction. All produced catalysts were electrochemically characterized using cyclic voltammetry and oxidation of CO monolayer, while the influence of thermal annealing on the morphology was monitored using an atomic

One of the most popular alternative sources of energy are direct methanol fuel cells (DMFCs) with platinum-based catalysts due to their non-toxicity, reduced emissions of hazardous pollutants and high energy density. However, significant challenges of the scientific community related to Pt catalysts are the high cost, depletable resources and formation of poisoning species i.e. CO, during the methanol oxidation reaction. To reduce the amount of expensive Pt and susceptibility of Pt to poisoning species and simultaneously improve its catalytic performance, recent studies are focusing on the synthesis of Pt alloys in which a certain amount of platinum is replaced with less expensive metals such as Ru, Sn, Ni, Cu, Rh and Co. The usage of carbon (Vulcan XC-72R) for catalyst support enables high dispersion of metal, high surface area and good electrical conductivity improving overall performances of DMFCs. In this work, PtZn/C and PtSnZn/C catalysts were synthesized by the microwave-assisted polyol method. The structure and morphology of the catalysts were characterized by transmission electron microscopy (TEM), thermogravimetric (TG) and X-ray diffraction (XRD) analysis. The activity and stability of synthesized catalysts for methanol oxidation in 0.5 M sulfuric acid were investigated. It was demonstrated that the activity of the platinum catalysts was improved thanks to the synergistic effects caused by the addition of different metals, such are bifunctional and electronic effects.

Due to their high electrocatalytic activity, Pt-based materials are widely investigated as electrocatalysts for the electro-oxidation of small organic molecules for fuel cells technology applications, contributing to the potential reduction of fossil fuel use in the near future. In addition to methanol, formic acid has also gained increasing attention as a potential fuel for direct fuel cells due to lower toxicity, non-flammability and a lower storage cost. The electro-oxidation of formic acid on Pt-based thin films is taking place predominantly via indirect pathway, through the dehydrogenation reaction of formic acid, with the formation of CO as a poisoning species. The activity of electrocatalysts is dependent both on surface structure and surface orientation in terms of the arrangement of the atoms at the surface. Controlled heat treatment led to the rearrangement of surface atoms thus enhancing the catalytic properties. In order to investigate changes in morphology before and after thermal annealing, Pt/CrNi catalysts were characterized using an atomic force microscope (AFM). The performance of all catalysts was tested in formic acid electro-oxidation reaction. The synergistic effect of individual metallic components, in the designed catalyst, resulted in high activity and exceptional stability. The approach demonstrated in this work may promote the development of new generation of high-performance catalysts for use in direct formic acid fuel cells (DFAFCs).

The processes of nucleation and growth of tin dendrites from the alkaline hydroxide solution have been investigated. Nucleation of tin was examined by chronoamperometry at the cathodic potentials which belonged to various positions at the polarization curve. The morphology of potentiostatically electrodeposited tin dendrites with various amounts of the electricity was characterized by scanning electron microscopy (SEM) technique. Depending on the cathodic potential applied for Sn electrodeposition, the following forms of Sn dendrites were obtained: the needle-like, the spear-like and the fern-like dendrites of various degree of ramification. Combining Sharifker and Hills (SH) model for a determination of nucleation type and results of morphological analysis of Sn dendrites, it is concluded that nucleation of Sn from the alkaline hydroxide solution follows the progressive type of nucleation., Analizirani su procesi nukleacije i rasta dendrita kalaja iz alkalnog hidroksilnog rastvora. Nukleacija kalaja je bila ispitana hronoamperometrijom na katodnim potencijalima koji su pripadali različitim pozicijama na polarizacionoj krivoj. Morfologija potenciostatski elektrohemijski istaloženih dendrita kalaja sa različitim količinama elektriciteta je bila okarakterisana tehnikom skenirajuće elektronske mikroskopije (SEM). U zavisnosti od katodnog potencijala primenjenog za elektrohemijsko taloženje kalaja, formirani su sledeći oblici dendrita kalaja: igličasti, dendriti nalik koplju i dendriti nalik paprati različitog stepena razgranatosti. Kombinovanjem Šarifkerovog i Hilsovog (SH) modela za određivanje tipa nukleacije i rezultata morfološke analize dendrita kalaja, zaključeno je da nukleacija kalaja iz alkalnog hidroksilnog rastvora sledi progresivni tip nukleacije.

Heat stress seriously affects the production of cool-season food legume crops such as garden peas. Seed priming is a widely used technique that increases germination and improves plant growth and development, resulting in better field performance and higher yield of crops. In the current study, we investigated three seed priming treatments—hydropriming (dH2O), osmopriming (2.2% w/v CaCl2), and hormopriming (50 mg L-1 salicylic acid - SA)—and their effect on germination, initial seedling development, and physiological traits of two novel garden pea cultivars, under optimal conditions and heat stress. Seed priming with H2O, CaCl2, and SA enhanced garden pea performance under both optimal and stress conditions via significant improvements in germination energy, final germination, mean germination time, mean germination rate, seedling vigor index, shoot length, root length, fresh seedling weight, dry seedling weight, shoot elongation rate, root elongation rate, relative water content, chlorophyll content, and membrane stability index, as compared to control. The highest effect on the examined parameters was achieved by osmopriming and hormopriming in both cultivars, suggesting that these treatments could be used to improve the heat stress tolerance of garden pea, after extensive field trials

Kaolinite/illite (KUb) and sepiolite (SEP) clays were used to study Cr(III) adsorption removal from aqueous solutions so that they could be utilized after saturation for ceramic manufacturing. SEP had a larger specific surface area and a higher PZC than KUb. The removal of Cr(III) was evaluated using a batch equilibration procedure at pHi = 4 and pHi = 6. Fast removal kinetics were observed for both clays. Maximum removal capacity was determined by changing the concentration of Cr(III) while keeping the concentration of clay constant and by altering the amount of clay while keeping the concentration of Cr(III) constant. In all situations, SEP had greater capacity than KUb, and capacity was greater for both clays at higher pHi. Not only did the pHi impact the removal capacity and efficiency, but so did the pH during adsorption and the initial concentration of Cr(III). Because of the higher PZC, the pHf for SEP was higher for the same pHi. The higher the pH and Cr(III) concentration, the higher the probability of Cr(OH)3 precipitation and the higher the removal capacity. Dried saturated clays were uniaxially pressed and sintered at 1000 °C for 2 h. The densities of the sintered materials were nearly identical to those of pure clay-based materials, but the compressive strengths were higher, which is significant for the use of saturated clays as raw materials in ceramic manufacturing. Leaching of Cr from SEP-based material was significantly higher than from KUb-based material probably due to the presence of CaCO3 in the SEP.

Tehničko rešenje se odnosi na unapređenje postupka prečišćavanja otpadnih voda koje sadrže trovalentni hrom, kao što su otpadne vode iz površinske zaštite metala, štavljenja kože, zaštite drvenih proizvoda i dr. U konvencionalnim postupcima joni trovalentnog hroma se talože u obliku Cr(OH)3, čime nastaje talog kao sekundarni opasni otpad koji se uglavnom odlaže na deponije, što dovodi do dodatnih troškova i negativnog uticaja na životnu sredinu. U ovom tehničkom rešenju joni trovalentnog hroma se uklanjaju iz vode adsorpcijom na jeftinim glinama iz lokalnih ležišta, jednoj kaolinitsko-ilitskog tipa i jednoj na bazi sepiolita, koje su komercijalno dostupne kao sirovine za proizvodnju tradicionalne keramike. Utvrđen je adsorpcioni kapacitet ovih glina, pri različitim pH vrednostima, variranjem početne koncentracije jona hroma pri konstantnoj koncentraciji adsorbenta, kao i variranjem koncentracije adsorbenta pri konstantnoj koncentraciji jona hroma, u cilju optimizacije procesa prečišćavanja. Imajući u vidu da regeneracijom zasićenih adsorbenata nastaju nove otpadne vode, ovim tehničkim rešenjem je predviđeno da se zasićeni adsorbenti koriste kao sirovine za proizvodnju keramike umesto čistih glinenih minerala. Određivanje pritisne čvrstoće sinterovanih materijala dobijenih od zasićenih adsorbenata je pokazalo da adsorbovani joni hroma ne pogoršavaju mehanička svojstva u poređenju sa materijalima koji su dobijeni od čistih glina, već naprotiv dovode do povećanja pritisne čvrstoće i to u većoj meri u slučaju materijala na bazi sepiolitske gline, čiji je kapacitet adsorpcije veći. Ispitivanja izluživanja hroma iz sinterovanih materijala na bazi zasićenih adsorbenata su pokazala da je izluživanje u slučaju materijala na bazi sepiolitske gline veće od vrednosti koja je definisana odgovarajućim standardom, verovatno zbog prisustva kalcijum-karbonata kao primese ove gline. Ovaj problem se može prevazići povišenjem temperature sinterovanja. Hrom je efikasno imobilisan u mate

In the 2018–19 growing season, a total of 51 leaves of eggplant plants grown under field conditions were collected randomly from nine private gardens at four different localities in the Province of Vojvodina. Eggplants with nearly 40% of plants showing bright yellow to white mosaic or mottling of leaves were found throughout the inspected fields (gardens). The collected samples were analyzed for the presence of alfalfa mosaic virus (AMV), cucumber mosaic virus (CMV) and potato virus Y (PVY) using commercial double-antibody sandwich (DAS)-ELISA kits. Serological analysis of eggplant samples revealed the presence of AMV in 80.39% collected samples. None of the analyzed samples was positive for CMV and PVY. The virus was successfully mechanically transmitted to test plants including Nicotiana benthamiana, Chenopodium quinoa, C. amaranticolor, as well as eggplant seedlings, confirming the infectious nature of the disease. The presence of AMV in eggplants was further verified by reverse transcription–polymerase chain reaction (RT-PCR) and sequencing, using the primers CP AMV1 and CP AMV2 that amplify part of the coat protein (CP) gene. The phylogenetic analysis showed that Serbian AMV isolates grouped into a separate well-supported group together with AMV isolates from Italy, Croatia and previously characterized isolates from Serbia. To our knowledge, this is the first report of AMV infection of eggplant in Serbia., Tokom 2018. i 2019. godine, prikupljen je 51 uzorak biljaka plavog patlidžana iz devet useva sa četiri različita lokaliteta gajenja ove biljne vrste u Vojvodini. Tokom pregleda, na blizu 40% biljaka plavog patlidžana mogli su se uočiti simptomi u vidu žućkastobeličastih pega raspoređenih po čitavoj površini liske. Prikupljeni uzorci analizirani su na prisustvo virusa mozaika lucerke (alfalfa mosaic virus, AMV), virusa mozaika krastavca (cucumber mosaic virus, CMV) i Y virusa krompira (potato virus Y, PVY) korišćenjem komercijalno dostupnih kitova za DAS-ELISA test. Serološkim analizama utvrđeno je prisustvo AMV u 80,39% prikupljenih uzoraka. Prisustvo CMV i PVY nije dokazano ni u jednom od testiranih uzoraka. Virus je uspešno prenet mehaničkim inokulacijama test biljaka Nicotiana benthamiana, Chenopodium quinoa, C. amaranticolor, kao i na klijance plavog patlidžana, čime je potvrđena infe ktivna priroda oboljenja. Prisustvo AMV u biljkama plavog patlidžana je dalje potvrđeno primenom RT-PCR metode (reverzna transkripcija praćena lančanom reakcijom polimeraze) i sekvencioniranjem odabranih izolata korišćenjem specifičnih prajmera CP AMV1 i CP AMV2, koji omogućavaju umnožavanje gena za protein omotača. Filogenetska analiza pokazala je grupisanje srpskih AMV izolata u jasno odvojenu grupu zajedno sa AMV izolatima iz Italije, Hrvatske i prethodno okarakterisanim izolatima iz Srbije. Prema našim saznanjima, ovo je prvi izveštaj o prisustvu virusa mozaika lucerke na plavom patlidžanu u Srbiji.

U usevu pasulja i boranije širom sveta zabeleženo je preko 200 oboljenja različite etiologije, međutim u mnogim delovima sveta najznačajnije štete u proizvodnji mahunarki izazivaju upravo biljni virusi. Pasulj je domaćin 44 različita virusa među kojima su najvažniji virus običnog mozika pasulja (Bean common mosaic virus, BCMV), virus običnog nekrotičnog mozaika pasulja (Bean common mosaic necrosis virus, BCMNV), virus žutog mozaika pasulja (Bean yellow mosaic virus, BYMV) i virus mozaika krastavca (Cucumber mosaic virus, CMV). Virusi pasulja se prenose semenom i/ili vašima na neperzistentan način, što je jedan od glavnih uzroka široke rasprostranjenosti ovih virusa u svetu. Virusna oboljenja na pasulju i boraniji se ispoljavaju u vidu različitih tipova simptoma, a najčešći su mozaik, šarenilo, deformacija lišća i promene na mahunama, koji imaju za posledicu smanjenje porasta biljaka i prinosa., Over 200 diseases with different etiologies have been determined in dry beans and green beans. However, viral diseases seem to cause the greatest economic damage to legume production in most parts of the world. Dry beans can be infected by 44 different viruses including Bean common mosaic virus (BCMV), Bean common mosaic necrosis virus (BCMNV), Bean yellow mosaic virus (BYMV) and Cucumber mosaic virus (CMV). Transmission through seeds and/or spread by aphids in non-persistent manner play important role in worldwide distribution of bean viruses. Viral diseases on dry and green beans can have an array of symptoms. The most common symptoms are the mosaic pattern, variegation or deformation of leaves and pods, resulting in reduced plant growth and yield.

Safflower (Carthamus tinctorius L.) is an important oilseed crop belonging to the family Asteraceae. A total of 46 safflower samples were collected from Srbobran locality (South Bačka District) in Serbia in 2015 and analysed for the presence of cucumber mosaic virus (CMV), alfalfa mosaic virus (AMV), and lettuce mosaic virus (LMV), using commercial double-antibody sandwich (DAS)-ELISA kits. Both viruses, CMV and AMV, were detected serologically in the collected samples. None of the analysed samples was found to be positive for LMV. The presence of CMV was further confirmed by mechanical transmission to test the plants including Chenopodium quinoa, C. amaranticolor, Nicotiana glutinosa, and Datura stramonium as well as C. tinctorius, confirming the infectious nature of the disease. Molecular detection of CMV was performed by amplification of a 871 bp fragment in all the tested samples, using the specific primers CMVCPfwd/CMVCPrev that amplify the entire coat protein (CP) gene and part of 3'- and 5'-UTRs of CMV RNA 3. The RT-PCR products derived from the isolates 290Saff and 294Saff were sequenced (MH577791 and MH577792, respectively) and compared with the CMV sequences available in GenBank. Phylogenetic analysis based on CP gene sequences showed clustering of the selected isolates into three subgroups: IA, IB and II. Serbian CMV isolates found in safflower belong to subgroup II. To our knowledge, this is the first report on CMV infection of safflower in Serbia, which has the potential to cause substantial damage to safflower production and pose a threat to other economic crops grown in Serbia.