COMPARISON OF SENSING PROPERTIES OF SnO2/KIT-5 AND SnO2 HUMIDITY SENSORS

In this work, two different syntheses approaches – nanocasting and sol-gel technique were employed for the preparation of SnO2 powders for humidity sensors. Stock solution of SnCl2 in ethanol (0.5 M) was used as a Sn-precursor for both syntheses. In the first procedure, this solution was infiltrated by wet impregnation method into the hydrothermally prepared KIT-5 used as silica template. Mesoporous SnO2/KIT-5 hybrid was obtained after two step loading/calcination process. Calcination was performed at 550 C for 5 h. In the second procedure, silica template was excluded from synthetic path. Ethanol solution of SnCl2 was slowly heated to form the gel which was later submitted to the same calcination conditions resulting in the preparation of SnO2 nanopowder. By dispersing the as prepared powders in the ethyl-cellulose/α-terpineol solution and adding a few drops of acetic acid in the mixture, viscous pastes were prepared and further homogenized for 24 h with magnetic stirrer. Using doctor blade applicator a few micron thick films were deposited onto alumina substrates provided with interdigitated Pt/Ag electrodes. Sensors’ characteristics were compared by measuring the change of the complex impedance of the samples exposed to a humid climate chamber environment at different temperatures and RH values from 40 % to 90 % at 25 °C and from 30 % to 90 % at 50 °C. The value of impedance measured at 42 Hz and within the RH range of 40 % to 90 %, changes 53 times at 25 °C, and 96 times at 50 °C. In contrast, for the sensor prepared from chemically derived SnO2, the impedance changes in a moderate way – 8 times at 25 °C and 3 times at 50 °C. Fast response/recovery time of the SnO2/KIT-5 hybrid sensor exposed to humidity change from 40 % – 90 % at room temperature, confirmed superior potentials of this material for humidity sensing over the SnO2

Evaluation of pig welfare in lairage and process hygiene in a single abattoir

Food safety is indirectly affected by the welfare of food animals, due to close links between animal welfare, animal health and food borne diseases. Stress factors and poor welfare can lead to increased susceptibility to disease among animals and may intensify the fecal shedding of food borne pathogens, e.g. Salmonella, Campylobacter, Yersinia, and human pathogenic STEC in the pre-slaughter phase: on-farm, in transport and in lairage. This study evaluated two aspects: a) assessment of pig welfare in abattoir lairage founded on animal-based categories, and b) the relationship between pig welfare and microbial process hygiene at slaughter. The results revealed that the animal-based category ‘manure on the body’ assessed in abattoir lairage corresponded with microbial process hygiene at slaughter

Parametri rodnosti različitih sorti jarog ječma (Hordeum vulgare L)

This paper presents the results of Kragujevac spring barley varieties (Jadran and Dunavac). The experiment was conducted at the experimental field of the Center for Small Grains, Kragujevac during two growing seasons. Investigated the grain yield (t ha-1), 1000 grain weight (g) and test weight (kg hl-1). By examining the physical properties of grain, variety Jadran is made slightly larger two-year average grain yield (3.127 t ha-1). The average value for 1000 kernel weight and test weight in both years was slightly higher in the variety Dunavac.U radu su prikazani rezultati istraživanja kragujevačkih jarih sorti ječma (Jadran i Dunavac). Ogled je postavljen na oglednom polju Centra za strna žita, Kragujevac tokom dve vegetacijske sezone. Istraživan je prinos zrna, masa 1000 zrna i hektolitarska masa. Prosečan prinos zrna u posmatranom dvogodišnjem periodu kretao se u intervalu od 2,674 t ha-1 do 3,127 t ha-1, dok se vrednost za masu 1000 zrna kretala u intervalu od 44,16 g do 44,48 g. Sorta Jadran je ostvarila nešto veći dvogodišnji prosečan prinos zrna (3,127 t ha-1). Prosečna vrednost za masu 1000 zrna i hektolitarsku masu u obe godine istraživanja bila je nešto veća kod sorte Dunavac

Uticaj godine na prinos i kvalitet zrna ozimih sorti pšenice

The small-scale trials over two years (2009/10th and 2010/11th), examined the six varieties of winter wheat (Vizija, Takovčanka, Kg 56 S, Kruna, Aleksandra and Planeta). Studied grain yield (t ha-1), weight of 1000 grains (g) and test weight (kg hl-1). Estimates were statistically significant differences for grain yield between varieties and years. Cultivars Vizija, Kg 56 S, Takovčanka and the Kruna have conducted surveys have shown a high degree of adaptability conditions of production of wheat and had a satisfactory yield in the examined vegetation seasons.U mikroogledima tokom dve godine (2009/10.-2010/11.), ispitivano je šest sorti ozime pšenice (Vizija, Takovčanka, Kg 56 S, Kruna, Aleksandra i Planeta). Istraživan je prinos zrna (t ha-1), masa 1000 zrna (gr) i hektolitarska masa (kg hl-1). Procenjene su statistički signifikantne razlike za prinos zrna između sorti i godina. Sorte Vizija, Kg 56 S, Takovčanka i Kruna su u sprovedenim ispitivanjima pokazale visok stepen adaptabilnosti uslovima proizvodnje pšenice i imale su zadovoljavajući prinos u ispitivanim godinama

Electrochemical Synthesis of Flower like Magnesium Oxide/Hydroxide from Magnesium Nitrate Melt

The magnesium oxide (MgO)/magnesium hydroxide (Mg(OH)2) in recent years have received considerable attention as one of the nanomaterials intended for specific application. The interest in this material is standing from promising utilization in next generation solar cells, advanced catalysis, medicine, toxic waste remediation and similar. More advanced utilizations, however, require controlled surface morphology and composition of the oxy/hydroxide. It is now common knowledge that electrodeposition technique provides a suitable way to obtain materials of micro or nano scales in the desired forms. Additionally, shape and size of the deposited material can be conveniently controlled by the choice of parameters and regimes of electrolysis. A novel approach to electrochemical synthesis of magnesium oxide/hydroxide meso - and nanostructures on glassy carbon electrode from the melt made of magnesium nitrate hexahydrate melt at 100 °C have been considered. The electrodeposition of magnesium oxide/hydroxide commences in magnesium underpotential (UPD) and continues through the magnesium overpotential (OPD) region. Chronoamperometric analysis showed that magnesium oxides/hydroxides syntheses taking part simultaneously at various applied potentials are a result of reactions between magnesium cations and products of water and nitrate anions reduction processes. Chemical reactions responsible for direct formation of magnesium oxide observed are those of magnesium ions and oxygen ions, formed by nitrate reduction taking part in the close vicinity of the working electrode. The morphology of magnesium oxide/hydroxide obtained by galvanostatic regime were characterised using scanning electron microscopy (SEM) technique. Network of individual very thin needles were formed in both magnesium UPD and OPD region, as well as those grouped in flower-like aggregates in magnesium OPD regions, Fig.1

Formation of MgO/Mg(OH)2 Nanostructures by Molten Salt Electrolysis

Thanking its unique characteristics, magnesium oxide and magnesium hydroxide nanostructures are of high practical significance for possible application in the next generation of solar cells, electronic devices, displays, in detection and adsorption of different environmental pollutants [1]. Numerous methods of synthesis including precipitation, solvothermal and hydrothermal processes, the sono-chemical technique, the sol-gel method, microwave methods, chemical vapor deposition, carbonatization and electrochemical method are widely used for synthesis of various forms magnesium oxide/magnesium hydroxide nanostructures such as whiskers, platelets, rods, needle-like, flower like etc. Electrochemical method attracts a special attention in a production of nanostructures owing to easy control of morphology of particles by the choice of regimes and parameters of electrolysis. In this study, the processes of electrolysis from magnesium nitrate hexahydrate melt in the both potentiostatic and galvanostatic conditions were analyzed. Morphologies of synthesized particles were characterized by scanning electron microscopy (SEM) technique. The X-ray diffraction (XRD) analysis of produced particles showed that the mixture of magnesium oxide and magnesium hydroxide was formed by these molten salt electrolysis processes [2,3]. No any difference in surface morphology was observed between these two constant regimes of electrolysis. The very thin needles often grouped in flower-like aggregates were obtained by the electrolysis processes. The special attention was devoted to the effect of hydrogen as parallel reaction to processes of electrolysis. In the dependence of parameters of electrolysis (potential or current density applied), holes formed from detached hydrogen bubbles of various shape and size from dish-like holes to those creating the honeycomb-like structures were formed. Mechanism of formation of all observed morphological forms was considered. Also, comparison with electrolysis processes from aqueous magnesium salt electrolytes was made and discussed. 1. A.A. Pilarska, Ł. Klapiszewski, T. Jesionowski, Powder Technol., 319 (2017) 373 2. V.S. Cvetković, N.M. Vukićević, et al., Electrochim. Acta, 268 (2018) 494 3. N.M. Vukićević, V.S. Cvetković, N.D. Nikolić, G. Branković, T.S. Barudžija, J.N. Jovićević, J. Serb. Chem. Soc., 83 (2018) 135

Effects of the silver nanodots on the photocatalytic activity of mixed-phase TiO2

We present the synthesis and photocatalytic properties of mixed-phase TiO2 nanoparticles decorated with silver nanodots obtained by environmental-friendly wet chemical method using low molecular weight chitosan as the silver reducing agent. Structural analysis of synthesized Ag nanoparticles revealed that they crystallized in a rare hexagonal modification. High-resolution transmission electron microscopy study shows that lt 3-nm hexagonal-Ag nanoparticles are implanted on the surface of lt 20-nm anatase grains. Compared to Ag-free TiO2 powders, implantation with Ag results in important increase in visible light absorption. The photocatalytic activity of the samples was measured by monitoring decolorization of concentrated textile dye solution (50 mg L-1 of Reactive Orange 16) under simulated solar irradiation of 280 W m(-2). The optimum photocatalytic properties are achieved with 5 wt% of silver. Based on the collected results, the operating mechanism of the degradation process is suggested, and the effects of the silver addition are explained

A Novel KCNA2 Variant in a Patient with Non-Progressive Congenital Ataxia and Epilepsy: Functional Characterization and Sensitivity to 4-Aminopyridine

Kv1.2 channels, encoded by the KCNA2 gene, are localized in the central and peripheral nervous system, where they regulate neuronal excitability. Recently, heterozygous mutations in KCNA2 have been associated with a spectrum of symptoms extending from epileptic encephalopathy, intellectual disability, and cerebellar ataxia. Patients are treated with a combination of antiepileptic drugs and 4-aminopyridine (4-AP) has been recently trialed in specific cases. We identified a novel variant in KCNA2, E236K, in a Serbian proband with non-progressive congenital ataxia and early onset epilepsy, treated with sodium valproate. To ascertain the pathogenicity of E236K mutation and to verify its sensitivity to 4-AP, we transfected HEK 293 cells with Kv1.2 WT or E236K cDNAs and recorded potassium currents through the whole-cell patch-clamp. In silico analysis supported the electrophysiological data. E236K channels showed voltage-dependent activation shifted towards negative potentials and slower kinetics of deactivation and activation compared with Kv1.2 WT. Heteromeric Kv1.2 WT+E236K channels, resembling the condition of the heterozygous patient, confirmed a mixed gain- and loss-of-function (GoF/LoF) biophysical phenotype. 4-AP inhibited both Kv1.2 and E236K channels with similar potency. Homology modeling studies of mutant channels suggested a reduced interaction between the residue K236 in the S2 segment and the gating charges at S4. Overall, the biophysical phenotype of E236K channels correlates with the mild end of the clinical spectrum reported in patients with GoF/LoF defects. The response to 4-AP corroborates existing evidence that KCNA2-disorders could benefit from variant-tailored therapeutic approaches, based on functional studies