Primena anodne oksidacije hlorida, bromida i cirkonijuma u organskoj sintezi

U ovom radu ispitani su reakcioni uslovi pod kojima anodna oksidacija može da se primeni kao sredstvo za postizanje određenih sintetičkih ciljeva, pri čemu se sama sintetička reakcija ne odvija na elektrodama. Tokom istraživanja obuhvaćenih izradom ove teze detaljno su razrađeni postupci upotrebe anode kao oruđa za izvršenje tri konkretna sintetička zadatka: - sinteza hlorovanih sekundarnih metabolita nekih lišajeva hlorovanjem fisciona (48), prirodnog, polifunkcionalnog antrahinona; - sinteza prirodnog proizvoda kurkumenskog etra ((±)-52); - sinteza 2-nezasićenih peracetilovanih glikozida iz odgovarajućih glikala (Ferijeovo premeštanje), kao i 3-tia- i 3-azaketona iz odgovarajućih konjugovanih karbonilnih jedinjenja primenom cirkonijumovih jedinjenja kao katalizatora (hetero-Majklova adicija). Uloga anode u ostvarivanju ova tri cilja je različita: kod hlorovanja fisciona (48) anoda služi da bi se na njoj generisalo sredstvo za hlorovanje (slobodni hlor) iz nekog hlorida, u sintezi kurkumenskog etra ((±)-52) na njoj se generiše medijator za sprovođenje ključne reakcije (fenilselenoeterifikacija), a kod Ferijeovog premeštanja i hetero-Majklove reakcije na anodi se generiše katalizator reakcije. Hlorovanje fisciona (1,8-dihidroksi-6-metil-3-metoksi-antracen-9,10-diona; 48) anodno generisanim hlorom zamišljeno je kao elektroliza rastvora nekog hlorida u podesnom rastvaraču, u prisustvu fisciona. Da bi se tome pristupilo, sprovedena su obimna ciklovoltametrijska merenja u dva rastvarača – sirćetnoj kiselini i dihlormetanu (osnovni elektrolit - tetrabutilamonijum-perhlorat). Njihov cilj bio je da se utvrdi da li se pri oksidaciji hlorida odigrava neki sporedni proces, npr., da li i fiscion na potencijalima bliskim redoks potencijalu hlorida podleže oksidaciji. Na osnovu ciklovoltamograma fisciona (48), tetraetilamonijum-hlorida i ove dve supstance zajedno, utvrđeno je da u širokoj oblasti potencijala sa radnom elektrodom elektrone razmenjuju samo hloridi (dajući hlor) i (tako dobijeni) hlor (dajući nazad hloride). Ti rezultati omogućili su pristupanje anodnom generisanju hlora u sredini koja sadrži fiscion (48) (preparativnoj elektrolizi) bez bojazni od sporednih elektrodnih reakcija ovog antrahinona.In this work, the reaction conditions of the application of anodic oxidation as a means to achieving certain synthetic tasks were studied, whereby the primary synthetic reaction does not take place at the electrodes. Throughout these investigations, the protocols of the use of the anode as a tool in the realization of three specific goals were optimized in detail: - The synthesis of chlorinated secondary metabolites of some lichens by chlorination of physcion (48), a natural, polyfunctionalized anthraquinone; - The synthesis of a natural product curcumene ether ((±)-52); - The synthesis of 2-unsaturated peracetylated glycosides from the corresponding glycals (Ferrier rearrangement), as well as 3-thia- and 3-azaketones from the corresponding conjugated carbonyl compounds by using zirconium compounds as the catalyst (hetero Michael reaction). The role of the anode in these three tasks differed: in the chlorination of physcion (48) it served to generate a chlorinating agent (free chlorine) from chloride, in the synthesis of curcumene ether ((±)-52) a mediator was generated at the anode in order to promote the key reaction (phenylselenoetherification), and a catalyst was generated at the anode that could promote Ferrier rearrangement and hetero Michael addition. The chlorination of physcion (1,8-dihydroxy-3-methoxy-6-methylanthracene-9,10- dione; 48) by chlorine generated at the anode was conceptualized as the electrolysis of a solution of a chloride in an appropriate solvent, in the presence of physcion. In order to do this, comprehensive cyclovoltammetric measurements in two solvents – acetic acid and dichloromethane (tetrabutylammonium perchlorate as the supporting electrolyte) - were carried out, aimed to establish whether any side processes take place during the oxidation of chlorides, e.g., whether also physcion undergoes oxidation at the potentials near to the chloride redox potential. On the basis of the obtained cyclovoltammograms of physcion (48), tetraethyammonium chloride and these substances together, it was found that, in a broad potential window, chlorides were the only species exchanging electrons with the working electrode (giving chlorine), as well as the thus obtained chlorine (giving back chloride). These results have enabled access to the anodic generation of chlorine in the media containing physcion (48) (a preparative electrolysis) without the risk of electrode side reactions occurring with this anthraquinone

Kinetika sušenja i analiza skupljanja biomaterijala korenja Valeriana officinalis

Drying kinetics and shrinkage of valerian plant root (Valeriana officinalis) was investigated during the convective hot air dryer with forced convection mode. Whole root without cutting, root cut into quarters, and root cut into 2 mm thin slices were used in drying experiments. Initial moisture content of roots was 51.2±0.3% and roots were considered to be dry when they lost 68% of the fresh weight and reached the moisture content of 10%. Drying air temperature was set to be 40 and 50°C, air velocity at 1 m/s. The relative humidity of drying air was not controlled and it depended on surroundings. The experimental results were fitted to the five thin layer drying models and according to the non-linear regression analysis Page model was most suitable to describe the drying kinetics. The characteristic drying curves were created for each experimental set and they showed that the samples' preparation strongly influenced the drying process and drying time. Experiments to determine shrinkage of different cell structures of valerian root were carried out for raw material, as well as for dried samples, by using optical and electron microscopy observations and measurements. It was observed that shrinkage processes are significantly dependent of the type of cell tissue and drying air temperature.Istraživanje kinetike sušenja i analiza skupljanja biomaterijala korenja lekovitog bilja Valeriana officinalis izvršeno je na konvektivnoj sušari sa vrućim vazduhom kao agensom sušenja. U eksperimentima su korišćeni uzorci: ceo koren, koren sečen na četvrtine i koren sečen na uzorke debljine 2 mm. Početni sadržaj vlage u uzorcima iznosio je 51.2±0.3%, a uzorak se smatrao suvim onda kada sadržaj vlage opadne na 10%. Temperatura vazduha u sušari iznosila je 40 i 50oC, sa brzinom strujanja od 1 m/s. Relativna vlažnost vazduha koji dospeva na materijal nije kontrolisana i zavisila je od spoljnih uslova. Eksperimentalni rezultati su analizirani kroz pet najčešće korišćenih modela za opisivanje promene bezdimenzionog sadržaja vlage u vremenu kod sušenja u tankom sloju, pri čemu je ustanovljeno da se kinetika sušenja najbolje opisuje modelom Page-a. Postupcima optičke i elektronske mikroskopije izvršeno je posmatranje uzoraka svežeg i osušenog korenja pri različitim režimima sušenja u cilju praćenja skupljanja materijala. Ustanovljeno je da proces skupljanja bitno zavisi od vrste ćelijskog tkiva u posmatranom poprečnom preseku materijala i od temperaturnog režima sušenja

Palinomorfološko proučavanje jagorčevine (Primula vulgaris Huds.) sa područja nacionalnog rezervata Obedska bara (Srbija)

The pollen morphology of primrose (Primula vulgaris, fam. Primulaceae) has been investigated using light and scanning electron microscopy to contribute to melissopalynological studies of honeys originating from the native apiflora. Palynomorphological investigation included the examination of pollen symmetry, polarity, ornamentation, aperturation, shape and size. The pollen grains are isopolar, radially symmetric and shed as monads. The exine ornamentation is reticulate. Analysis of pollen morphometric characteristics revealed that grains are small to medium size and prolate in shape. Given the aperturation, the number of colpi was mostly variable among individuals with a different type of flower ranging from 6 to 9.Palinomorfološka istraživanja jagorčevine (Primula vulgaris) koja su obuhvatila analizu osnovnih karakteristika polenovih zrna kao što su simetrija, polarnost, ornamentacija, aperturacija, oblik i veličina, obavljena su uz pomoć svetlosne i skenirajuće elektronske mikroskopije u cilju doprinosa melisopalinološkim istraživanjima meda poreklom iz apiflore različitih područja Srbije. Polenova zrna jagorčevine su izopolarna i radijalno simetrična, retikulatne ornamentacije. U pogledu aperturacije, evidentna je varijabilnost u broju brazdi na polenovim zrnima sakupljenim sa cvetova različitih individua, te su ona 6(-7) ili 8(-9)-zonokolpatna. Analiza morfometrijskih karakteristika polena pokazala je da polenova zrna po veličini spadaju u grupu malih do srednjih i da imaju prolatni oblik

Auditory training program For cochlear implanted pupils

Procesor pruža mogućnosti slušanja u različitim situacijama i okruženjima, ali koliko će dete dobro čuti i razumeti zavisi od više faktora:funkcionalne sposobnosti slušnog nerva, doba u trenutku ugrad- nje kohlearnog implanta, komunikacionih sposobnosti deteta, okruženja deteta. Cilj ovog rada je prikazivanje sadržaja programa individualnog slušnog treninga dece da kohlearnim implantom do koga se došlo višegodišnjim radom sa ovom decom. Sadržaji individualnog slušnog treninga sastoje se od slušnog prepoznavanja i percepcije određenog govornog materijala predvi- đenog programom za svaki nivo slušanja. U Školi „Stefan Dečanski“ na re-habilitaciji je od 2000. do 2013. godine bilo 52 kohlearno implantirane dece. Program individualnog slu- šnog treninga koji je proistekao iz našeg višegodišnjeg rada sa k.i. decom u školi, sadrži četiri nivoa. Svakom detetu prilazimo posebno i prime- njujemo odgovarajući nivo sadržaja programa. Prvi nivo: detekcija zvuka ( ima-nema); diskriminacija zvuka; sluša- nje i razumevanje govora i jezika. Drugi nivo:suprasegmentalna diskriminacija; identifikacija zvuko- va iz okruženja; slušanje i razumevanje govora i jezika. Treći nivo:slušanje i razumevanje zvukova iz okruženja; slušanje i razu- mevanje govora i jezika. Četvrti nivo:slušanje i razumevanje govora i jezika; upotreba tele- fona.Processor provides the option of listening in different situations and environments, but the ability of a child to hear and understand depends on several factors: functional ability of auditory nerve, age at the time of installation of cochlear implant, communication skills of the child,the child’s environment. The contents of individual auditory training consist of auditory recognition and perception of spoken material comprising a specific program for each level of listening. Rehabilitation process, in the school “Stefan Decanski”, has included 52 CI children from the year 2000 to 2013. Individual auditory training program that resulted from our many years of working with CI children in school consists of four levels.We approach each child individually and apply the appropriatlly level of program content. First level: detection of sound (yes – no); sound discrimination; listening and understanding of speech and language. Second level: discrimination of suprasegments; identification of environmental sounds; listening and understanding of speech and language. Third level: listening and understanding of environmental sounds; listening and understanding of speech and language. Fourth level: listening and understanding of speech and language; telephone usage

Removal of acetaldehyde form indoor air using NaA zeolite and Modernite

Indoor pollution nowadays can have serious effects on people’s health. The most common indoor pollutants in urban and industrial areas are volatile organic compounds – VOCs, which include acetaldehyde. Acetaldehyde vapors cause eye irritation, lung or respiratory tract problems and are considered cancerogenic. The aim of this research was to examine the adsorption properties of type NaA zeolite and Na-Form of modernite. Adsorption isotherms of acetaldehyde on the examined adsorbents were obtained by simulating adsorption in an indoor environment. The simulation chamber was set to the atmospheric pressure, the temperature of 25°C, and air humidity of 65%. The non-linear Langmuir model gave higher coefficients of determination (0.9675 and 0.9350, respectively) than those obtained using the Freundlich model (0.9563 and 0.9332, respectively), which is indicative of single-layer adsorption. Higher values of the Langmuir constant for the samples tested shows that there is only low affinity between the adsorbents examined and acetaldehyde. Maximum adsorption capacity (Q0m) in the monolayer obtained using the Langmuir model is 3.387 mg/g for NaA zeolite and 2.5293 mg/g for modernite. From this it can be fairly assumed that NaA zeolite as an adsorbent, is more suitable for removing acetaldehyde from indoor air

Pollen morphology and the flower visitors of Chaerophyllum coloratum L. (Apiaceae)

The pollen features of Chaerophyllum coloratum L., endemic to the Dinaric Alps, have been examined by both light microscopy and scanning electron microscopy in order to contribute to a better understanding of the taxonomic status of the species. Flower visitors have also been observed and analyzed with the aim of clarifying certain pollination aspects of the species including flower attractiveness especially to honeybees, and also in order to ascertain its contribution to the bee pasture. The pollen grains of C. coloratum are isopolar, radially symmetrical and medium sized. Polar axis (P) is 26.83±1.77 μm length, and equatorial diameter (E) is 9.17±0.57 μm length. P/E ratio amounts 2.90±0.10 indicating a perprolate shape. In an equatorial view, the grains are constricted in the equatorial region (bone-shaped), with obtuse polar caps. In polar view, they are triangular with obtuse angles and furrows in the sides of the triangle (interangular). The grains are tricolporate with three straight ectocolpi arranged regularly meridionally, of mean length 14.43±2.17 μm, each of which has one endopore. The characteristic internal thickenings around the protruding, clearly visible endopores (costae) in the constricted equatorial region are obvious in light microscopy. The ornamentation is psilate, irregularly rugulate (“cerebroid”), the exine surface is rather undulating. With regard to the observed fl ower visitors, the following pollination types occurred: melittophily, myophily, sapromyophily, cantharophily, and phalaenophily, and the most frequent pollinator was the honeybee

Olanzapine reverts the isolation-induced alterations in rat hepatic glutathionedependent defense system

Chronic psychosocial stress is a risk factor for depression. As the liver is a primary organ for drug activation and detoxification, the effect of chronic administration of olanzapine on rat hepatic glutathione (GSH)-dependent defense system including GSH, glutathione peroxidase (GPx) and glutathione reductase (GLR), following 21d of chronic social isolation stress (CSIS), an animal model of depression, was investigated. Increased GSH content in olanzapine-treated controls was found. Protein levels of GPx were increased in both vehicle- and olanzapine-treated chronically-isolated animals while significant increase in GPx activity was seen only in olanzapine-treated chronically-isolated animals. Reduced activity of GLR in CSIS group that was not in correspondence with its protein level was increased by olanzapine. The results imply that chronic administration of olanzapine reverts the alternations in hepatic GSH-dependent defense of stressed rats caused by CSIS

Effects of selenium nanoparticles on pathogenic and probiotic food bacteria, and their influence on human intestinal cells

Selenium is an especially important element for the functioning of antioxidative enzymes, making it one of the essential micronutrients. Although selenium is required in extremely small amounts, often it is lacking from the organism. However, inorganic and organic sources of selenium are known to possess considerable toxicity. Recently, the nanoparticle form of selenium has been shown to exhibit lesser toxicity, and also better antimicrobial and other biological effects, than selenium-containing compounds. Nanotechnology has already found application in many fields, for improving material properties for various purposes, among them, in the process of improving food characteristics. It is possible that selenium nanoparticles can be applied as antimicrobial agents in food, and there has been growing interest in this area of research. We have synthesized selenium nanoparticles (SeNPs) by chemical reduction method, using sodium selenite, ascorbic acid, and bovine serum albumin. The antimicrobial activity of these particles has been assessed by minimum inhibitory concentration assay and colony-forming units count, on Listeria monocytogenes and Salmonella enterica, which are common bacterial food contaminants. As intestinal microbiota, especially probiotic bacteria, have been shown to play important role in organism functioning, we also tested how SeNPs influence Lactobacillus rhamosus and Lactobacillus plantarum. To evaluate cytotoxicity, we used MTT assay on the human intestinal cell line (HT-29). Antioxidative properties were assessed by DPPH assay. SeNPs showed higher antibacterial activity on pathogenic bacteria than on probiotic strains. Cytotoxic effect was present only in the highest tested concentrations. The antioxidative activity was considerable, resulting in above 80% reduction of DPPH free radical, at 1 g/ml of SeNPs. Based on these results, SeNPs are a promising subject for further research in developing materials for food packaging or as antimicrobial selenium additives

EFFICIENCY OF BALL MANIPULATION IN BASKETBALL PLAYERS

Abstract. Basketball belongs to the type of sports where the skill of using one’s arms is of the greatest significance for game success. Basketball technique elements which involve the use of the ball are realized solely with the use of the arms, and this is where the name “ball manipulation” stems from. Modern basketball requires top basketball players to display the greatest level of the mentioned ability, irrespective of the playing positions within the team. The aim of this research has been to determine the situational-motor skill of a basketball player’s ball manipulation efficiency with regard to the basketball competition rank. A sample of 30 participants was analyzed, and split into two subsamples (the first subsample consisted of basketball players from the Super League, i.e. the players from the Konstantin basketball team from Nis – 15 participants, and other basketball players from the First Regional League for Men, the Junior Youth Basketball Club from Nis – 15 participants). The ball manipulation efficiency was estimated through the following tests: ball stopping, starting dribbling, ball dribbling around the body, ball dribbling through the legs and leading the ball with variants. In order to determine the inter-group differences, the Multivariate Analysis of Variance (MANOVA) was applied, while the differences between the groups were determined with the Analysis of Variance (ANOVA) for every measuring instrument separately. It was determined that the basketball players of the Super League display significantly greater values in almost all the variables, except one – ball stopping.Keywords: basketball players, ball manipulation, competition rank, differences.es

Synergistic Effects of the Supporting Material and Annealing Temperature on the Performance of Pt Thin Film Catalysts

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.Lectur