Determination of quantum yields of photochemical transformations of 2-, 3- and 4-2[(2-vinylphenyl)ethenyl]pyridines

U cilju nastavka proučavanja utjecaja heterocikličke jezgre na fotokemijsko ponašanje supstituiranih o-divinilbenzena razvijena je sinteza novih supstituiranih o-divinilbenzena s piridinskom jezgrom. Wittigovom reakcijom sintetizirani su novi piridinski produkti 2-2[(2-vinilfenil)etenil]piridin (1), 3-2[(2-vinilfenil)etenil]piridin (2) i 4-2[(2-vinilfenil)etenil]piridin (3) kao smjese geometrijskih izomera. Iz smjesa izomera uspješno su izolirani cis- i trans-izomeri koristeći kolonsku i tankoslojnu kromatografiju te su isti u potpunosti spektroskopski opisani. Svi novi sintetizirani derivati 1-3 podvrgnuti su fotokemijskim reakcijama na 300 nm u uvjetima sa i bez kisika u smjeru priprave novih bicikličkih struktura. Početni spojevi pokazali su različito fotokemijsko ponašanje. Fotoreakcija spoja 1 dovodi do zatvaranja u ciklizacijski spoj 7-etenil-benzo[f]kinolin (6), a uz njega izolirana su i opisana i dva intermedijara 7-etenil-10aH,10bH-cikloheksa[f]kinolin (4) i 7-etenil-1H,4H-benzo[f]kinolin (5). Uz ciklizacijski produkt nastala su dva produkta reakcijama cikloadicije i to biciklički produkt 2-(triciklo[6.1.1.02,7]deka-2,4,6-trien-9-il)piridin (7) te 3-azatetraciklo-[7.6.1.02,7.010,15]heksadeka-4-6,10(15),11,13-pentaen (8). Osvjetljavanjem spoja 2 dolazi do stvaranja većinskog ciklizacijskog spoja 7-etenil-benzo[f]izokinolina (9) (60 %) i manjinskog ciklizacijskog spoja 7-etenil-benzo[h]kinolina (10) (20 %) te bicikličkog produkta 3-(triciklo[6.1.1.02,7]deka-2,4,6-trien-9-il)piridina (11) (8 %). Osvjetljavanjem spoja 3 pokazalo se kako on uopće ne reagira već isključivo dolazi do reakcije trans-cis izomerizacije. S ciljem upotpunjavanja našeg razumijevanja fotokemijskih procesa koji se odvijaju, izračunali smo kvantna iskorištenja korištenjem ferioksalatog aktinometra. Polazni spojevi 1-3 kao i njihovi fotoprodukti okarakterizirani su modernim spektroskopskim metodama (jednodimenzionalni i dvodimenzionalni NMR, UV, IR i MS). Novi potencijalni farmakološki interesantni spojevi dobiveni su jednostavnim pristupom koristeći svjetlo kao reagens i pogodni su za daljnje transformacije i funkcionalizacije.As a continuation of the study of the effect of the heterocyclic ring on the photochemical behavior of o-divinylbenzenes, a syntheses of new derivatives with pyridine as a heterocycle were developed. New derivatives 2-2[(2-vinylphenyl)ethenyl]pyridine (1), 3-2[(2-vinylphenyl)ethenyl]pyridine (2) and 4-2[(2-vinylphenyl)ethenyl]pyridine (3) were synthesized by Wittig reaction as mixtures of isomers. Both of the isomers, cis- and trans-, were isolated by chromatographic and thin layer chromatographies and completely spectroscopically analyzed. All of the derivatives 1-3 were irradiated at 300 nm to see if they would react and give new bicyclic products. Derivatives of 2-, 3- and 4-pyridine showed versatile reactivity in given conditions. Photoreaction of 2-pyridine derivative (1) gave, by cyclisation reaction, compound 7-vinylbenzo[f]quinoline (6). We were also able to isolate 2 intermediates of this process, compounds 7-vinyl-10a,10b-dihydrobenzo[f]quinoline (4) and 7-vinyl-1,4-dihydrobenzo[f]quinoline (5). This derivative also gave, by reaction of cycloaddition, two new bicyclic compounds, 2-(tricyclo[6.1.1.02,7]deca-2,4,6-trien-9-yl)pyridine (7) and 3-azatetracyclo[7.6.1.02,7.010,15]hexadeca-4-6,10(15),11,13-pentaene (8). Irradiation of compound 2 gave one major and a minor product. Major product was 7-vinylbenzo[f]isoquinoline (9) (60 %) and the minor 7-vinylbenzo[h]quinoline (10) (20 %). These derivatives also gave a cycloaddition product 3-(tricyclo[6.1.1.02,7]deca-2,4,6-trien-9-yl)pyridine (11) (8 %). Irradiation of 4-pyridine derivative in various conditions showed that this compound did not react in other than in reactions of photoisomerisation. To enrich our understanding of the photochemical process taking place we calculated quantum yields by utilization of ferrioxalate actinometer. All of the compounds were characterized by spectroscopic methods (one- and two-dimensional NMR, UV, IR and MS)

Determination of quantum yields of photochemical transformations of 2-, 3- and 4-2[(2-vinylphenyl)ethenyl]pyridines

U cilju nastavka proučavanja utjecaja heterocikličke jezgre na fotokemijsko ponašanje supstituiranih o-divinilbenzena razvijena je sinteza novih supstituiranih o-divinilbenzena s piridinskom jezgrom. Wittigovom reakcijom sintetizirani su novi piridinski produkti 2-2[(2-vinilfenil)etenil]piridin (1), 3-2[(2-vinilfenil)etenil]piridin (2) i 4-2[(2-vinilfenil)etenil]piridin (3) kao smjese geometrijskih izomera. Iz smjesa izomera uspješno su izolirani cis- i trans-izomeri koristeći kolonsku i tankoslojnu kromatografiju te su isti u potpunosti spektroskopski opisani. Svi novi sintetizirani derivati 1-3 podvrgnuti su fotokemijskim reakcijama na 300 nm u uvjetima sa i bez kisika u smjeru priprave novih bicikličkih struktura. Početni spojevi pokazali su različito fotokemijsko ponašanje. Fotoreakcija spoja 1 dovodi do zatvaranja u ciklizacijski spoj 7-etenil-benzo[f]kinolin (6), a uz njega izolirana su i opisana i dva intermedijara 7-etenil-10aH,10bH-cikloheksa[f]kinolin (4) i 7-etenil-1H,4H-benzo[f]kinolin (5). Uz ciklizacijski produkt nastala su dva produkta reakcijama cikloadicije i to biciklički produkt 2-(triciklo[6.1.1.02,7]deka-2,4,6-trien-9-il)piridin (7) te 3-azatetraciklo-[7.6.1.02,7.010,15]heksadeka-4-6,10(15),11,13-pentaen (8). Osvjetljavanjem spoja 2 dolazi do stvaranja većinskog ciklizacijskog spoja 7-etenil-benzo[f]izokinolina (9) (60 %) i manjinskog ciklizacijskog spoja 7-etenil-benzo[h]kinolina (10) (20 %) te bicikličkog produkta 3-(triciklo[6.1.1.02,7]deka-2,4,6-trien-9-il)piridina (11) (8 %). Osvjetljavanjem spoja 3 pokazalo se kako on uopće ne reagira već isključivo dolazi do reakcije trans-cis izomerizacije. S ciljem upotpunjavanja našeg razumijevanja fotokemijskih procesa koji se odvijaju, izračunali smo kvantna iskorištenja korištenjem ferioksalatog aktinometra. Polazni spojevi 1-3 kao i njihovi fotoprodukti okarakterizirani su modernim spektroskopskim metodama (jednodimenzionalni i dvodimenzionalni NMR, UV, IR i MS). Novi potencijalni farmakološki interesantni spojevi dobiveni su jednostavnim pristupom koristeći svjetlo kao reagens i pogodni su za daljnje transformacije i funkcionalizacije.As a continuation of the study of the effect of the heterocyclic ring on the photochemical behavior of o-divinylbenzenes, a syntheses of new derivatives with pyridine as a heterocycle were developed. New derivatives 2-2[(2-vinylphenyl)ethenyl]pyridine (1), 3-2[(2-vinylphenyl)ethenyl]pyridine (2) and 4-2[(2-vinylphenyl)ethenyl]pyridine (3) were synthesized by Wittig reaction as mixtures of isomers. Both of the isomers, cis- and trans-, were isolated by chromatographic and thin layer chromatographies and completely spectroscopically analyzed. All of the derivatives 1-3 were irradiated at 300 nm to see if they would react and give new bicyclic products. Derivatives of 2-, 3- and 4-pyridine showed versatile reactivity in given conditions. Photoreaction of 2-pyridine derivative (1) gave, by cyclisation reaction, compound 7-vinylbenzo[f]quinoline (6). We were also able to isolate 2 intermediates of this process, compounds 7-vinyl-10a,10b-dihydrobenzo[f]quinoline (4) and 7-vinyl-1,4-dihydrobenzo[f]quinoline (5). This derivative also gave, by reaction of cycloaddition, two new bicyclic compounds, 2-(tricyclo[6.1.1.02,7]deca-2,4,6-trien-9-yl)pyridine (7) and 3-azatetracyclo[7.6.1.02,7.010,15]hexadeca-4-6,10(15),11,13-pentaene (8). Irradiation of compound 2 gave one major and a minor product. Major product was 7-vinylbenzo[f]isoquinoline (9) (60 %) and the minor 7-vinylbenzo[h]quinoline (10) (20 %). These derivatives also gave a cycloaddition product 3-(tricyclo[6.1.1.02,7]deca-2,4,6-trien-9-yl)pyridine (11) (8 %). Irradiation of 4-pyridine derivative in various conditions showed that this compound did not react in other than in reactions of photoisomerisation. To enrich our understanding of the photochemical process taking place we calculated quantum yields by utilization of ferrioxalate actinometer. All of the compounds were characterized by spectroscopic methods (one- and two-dimensional NMR, UV, IR and MS)

Alkali salts of nitranilic and cyanochloranilic acids

Series of novel alkali salts of nitranilic acid (3, 6-dinitro-2, 5-dihydroxyquinone) and cyanochloranilic acid (3-cyano-6-chloro-2, 5-dihydroxyquinone), and also of neutral cyanochloranilic acid dihydrate, were prepared and their structures were studied. The nitranilate dianion revealed a considerable conformational flexibility of nitro groups. Steric and inductive effects exerted by different substituents (nitro, cyano and chloro) and their influence on molecular geometry and crystal packing are discussed

Učinak mikronizacije na sastav i svojstvo brašna dobivenog od bijelog, žutog i crvenog zrnja kukuruza

The process of micronisation, a short time high temperature process that utilizes electromagnetic radiation in the infrared region to rapidly heat materials, is often used to improve storage stability of whole grain flour. In this work the consequences of such temperature treatment on the quality and solubility of proteins, viscosity, content of total phenolics, tocopherols, ß-carotene, as well as the antioxidant properties of maize (Zea mays L.) flour are presented. For these studies three maize hybrids were used: the semi-flint hybrid ZP 633 with pronounced yellow kernels, ZP Rumenka with dark red pericarp and yellow endosperm, and ZP 551b hybrid which is characterized by white kernels. The process of micronisation did not change the content of crude protein, the amount of albumin, globulin and zein were decreased, while glutelin remained the same or increased after micronisation. As a consequence of thermal effect on maize protein, tryptophan content was significantly decreased. Micronisation had a significant effect on the pasting properties of the selected maize flour. Viscosity of all micronised flour samples increased constantly, but without reaching a peak during heating of the slurry to 95 °C. At 95 °C it was slightly higher, but final viscosity at 50 °C was significantly lower. The micronisation treatment decreased the content of bioactive compounds (tocopherols, ß-carotene) naturally present in the raw grains. The whole grain flour from micronised grain, with modified nutritional and technological characteristics, represents a good raw material for production of gluten-free products.Mikronizacija, tj. postupak kratkotrajnog izlaganja materijala visokoj temperaturi pomoću elektromagnetskoga zračenja u infracrvenom području, često se primjenjuje za poboljšanje stabilnosti pri skladištenju cjelovitoga brašna žitarica. U radu je ispitan utjecaj takva postupka na kakvoću i topljivost proteina, viskoznost, udio ukupnih fenola, tokoferola i β-karotena, te na antioksidativna svojstva kukuruznoga brašna. Upotrijebljena su tri hibrida kukuruza (Zea mays L.): ZP 633, polutvrdunac izrazito žutih zrna; ZP Rumenka, tamnocrvenoga perikarpa i endosperma žute boje, te ZP 551b bijelih zrna. Mikronizacija nije utjecala na udio sirovih proteina, ali je smanjila udio albumina, globulina i zeina, dok je udio glutelina ostao nepromijenjen ili se neznatno povećao. Nakon toplinske obrade udio se triptofana znatno smanjio. Mikronizacija je također uvelike utjecala na vezivna svojstva brašna. Povećana je viskoznost svih uzoraka brašna, ali nije dosegla vrhunac zagrijavanjem suspenzije do 95 ºC. Na 95 ºC viskoznost je bila nešto veća, dok je pri završetku mikronizacije na temperaturi od 55 °C bila kudikamo manja. Mikronizacijom se smanjio udio bioaktivnih spojeva (fenola, tokoferola i β-karotena) prisutnih u sirovom zrnju. Cjelovito brašno dobiveno mikronizacijom zrnja žitarica zbog svojih je hranjivih i tehnoloških svojstava dobra sirovina za dobivanje bezglutenskih proizvoda

Učinak mikronizacije na sastav i svojstvo brašna dobivenog od bijelog, žutog i crvenog zrnja kukuruza

The process of micronisation, a short time high temperature process that utilizes electromagnetic radiation in the infrared region to rapidly heat materials, is often used to improve storage stability of whole grain flour. In this work the consequences of such temperature treatment on the quality and solubility of proteins, viscosity, content of total phenolics, tocopherols, ß-carotene, as well as the antioxidant properties of maize (Zea mays L.) flour are presented. For these studies three maize hybrids were used: the semi-flint hybrid ZP 633 with pronounced yellow kernels, ZP Rumenka with dark red pericarp and yellow endosperm, and ZP 551b hybrid which is characterized by white kernels. The process of micronisation did not change the content of crude protein, the amount of albumin, globulin and zein were decreased, while glutelin remained the same or increased after micronisation. As a consequence of thermal effect on maize protein, tryptophan content was significantly decreased. Micronisation had a significant effect on the pasting properties of the selected maize flour. Viscosity of all micronised flour samples increased constantly, but without reaching a peak during heating of the slurry to 95 °C. At 95 °C it was slightly higher, but final viscosity at 50 °C was significantly lower. The micronisation treatment decreased the content of bioactive compounds (tocopherols, ß-carotene) naturally present in the raw grains. The whole grain flour from micronised grain, with modified nutritional and technological characteristics, represents a good raw material for production of gluten-free products.Mikronizacija, tj. postupak kratkotrajnog izlaganja materijala visokoj temperaturi pomoću elektromagnetskoga zračenja u infracrvenom području, često se primjenjuje za poboljšanje stabilnosti pri skladištenju cjelovitoga brašna žitarica. U radu je ispitan utjecaj takva postupka na kakvoću i topljivost proteina, viskoznost, udio ukupnih fenola, tokoferola i β-karotena, te na antioksidativna svojstva kukuruznoga brašna. Upotrijebljena su tri hibrida kukuruza (Zea mays L.): ZP 633, polutvrdunac izrazito žutih zrna; ZP Rumenka, tamnocrvenoga perikarpa i endosperma žute boje, te ZP 551b bijelih zrna. Mikronizacija nije utjecala na udio sirovih proteina, ali je smanjila udio albumina, globulina i zeina, dok je udio glutelina ostao nepromijenjen ili se neznatno povećao. Nakon toplinske obrade udio se triptofana znatno smanjio. Mikronizacija je također uvelike utjecala na vezivna svojstva brašna. Povećana je viskoznost svih uzoraka brašna, ali nije dosegla vrhunac zagrijavanjem suspenzije do 95 ºC. Na 95 ºC viskoznost je bila nešto veća, dok je pri završetku mikronizacije na temperaturi od 55 °C bila kudikamo manja. Mikronizacijom se smanjio udio bioaktivnih spojeva (fenola, tokoferola i β-karotena) prisutnih u sirovom zrnju. Cjelovito brašno dobiveno mikronizacijom zrnja žitarica zbog svojih je hranjivih i tehnoloških svojstava dobra sirovina za dobivanje bezglutenskih proizvoda

Upotrebna vrednost kukuruzne biljke (biomase) za silažu

According to the estimation of leading experts, the maize utilisation for the production of silage from the whole plant, wet ear and wet grain should be one of the most important forms of its application in animal nutrition. Maize a major forage crop, because the highest accumulation of solar energy per area unit is accomplished by maize production and ensiling. At the Maize Research Institute, Zemun Polje, selection, testing and evaluation of silage maize. The aim of this study was to draw attention to this extremely significant field of science and studies on the utilisation of the whole maize plant (biomass) in feeding of domestic animals, primarily ruminants. This paper presents and discusses previous results and achievements of long-term scientific researches on the improvement of maize plant utilisation in making good-quality silage not only in our country but also in the world.Prema procenama vodećih stručnjaka korišćenje kukuruza za proizvodnju silaže od cele biljke, vlažnog klipa i vlažnog zrna trebalo bi da bude jedan od značajnijih oblika njegove primene u ishrani životinja. Kukuruz je najvažnija krmna biljka jer se njenom proizvodnjom i siliranjem postiže najviša akumulacija sunčeve energije po jedinici površine. U Institutu za kukuruz 'Zemun Polje' paralelno sa ispitivanjem i ocenom kvaliteta hibrida kukuruza namenjenih proizvodnji zrna vrši se selekcija, ispitivanje i ocena i silažnih formi kukuruza, odnosno upotrebne vrednosti i kvaliteta kukuruzne biljke za ishranu životinja. Kao rezultat ovog naučnoistraživačkog rada poslednjih nekoliko decenija selekcionisani su hibridi kukuruza koji su na osnovu ispitivanih parametara kvaliteta za silažne forme kukuruza visokog kvalitete. Karakteriše ih: visok prinos ukupne suve i ukupne svarljive suve materije po hektaru, visoko učešće suve materije klipa u ukupnom prinosu suve materije i visoka svarljivost suve materije cele biljke kukuruza. Cilj ovog rada bio je da se skrene pažnja na ovu izuzetno značajnu oblast nauke i istraživanja upotrebe cele kukuruzne biljke (biomase) u ishrani domaćih životinja, prvenstveno preživara. Prikazani su i diskutovani dosadašnji rezultati i dostignuća višegodišnjeg naučnoistraživačkog rada na unapređenju korišćenja kukuruzne biljke za spremanje kvalitetne silaže u našoj zemlji kao i u svetu. Opisan je kukuruz kao sirovina za proizvodnju i spremanje silaže od cele kukuruzne biljke kao kvalitetne kabaste hrane za ishranu domaćih životinja

EXPERIMENTAL AND NUMERICAL IDENTIFICATION OF STRUCTURAL MODES FOR ENGINEERING EDUCATION

Abstract. Development of simple classroom demonstration device and software for visualization of structural normal modes is presented. Device is made of parts of old speaker, controlled with personal computer, where the harmonic motion of solenoid is used as an excitation for beam and plate models. Simple code for finite element free vibration analysis of plates is written in Wolfram Mathematica. Good agreement of results and attractive visual patterns of normal modes attracted attention of students. Results are confirmed using modern modal testing methods. Presented approach is complementary to standard teaching of structural dynamics. Key words: engineering education, normal modes, Chladni plate, modal testing, finite element metho

White maize hybrids of the FAO maturity groups 500 and 600 – traits and composition

Pod kukuruzom belog zrna se smatra onaj tip kukuruza čiji endosperm ima jasnu belu boju, bez primesa pigmenta žute boje. Značaj kukuruza belog zrna se vremenom menjao u raznim zemljama i kulturama. Ako se ima u vidu globalna rasprostranjenost kukuruza belog i žutog zrna, zapaža se da kukuruz žutog zrna ima u svetu apsolutno dominantnu ulogu. Korišćenje kukuruza belog endosperma značajno se promenilo u poslednjih nekoliko decenija. Praktično prestala je njegova upotreba u ishrani domaćih životinja, dok je istovremeno povećano njegovo korišćenje za dobijanje specijalnih proizvoda za ljudsku ishranu i u mlinskoj preradi. Zbog toga su svojstva kvaliteta zrna postala jako važna i u selekcionom procesu poklanja im se ista pažnja kao i samom prinosu zrna. Cilj ovog rada bio je da se izvrši karakterizacija hibrida kukuruza belog zrna u pogledu morfološke građe, različitih fizičkih svojstva i osnovnog hemijskog sastava zrna kao pokazatelja njihove upotrebne vrednosti i kvaliteta. Pored toga, u radu su ispitivane i fizičke karakteristike klipa. Za ispitivanja je odabrano je pet zemunpoljskih hibrida kukuruza (tri hibrida belog i dva hibrida žutog zrna FAO grupa zrenja 500 i 600). Dobijeni rezultati su pokazali da se zrno ispitivanih hibrida kukuruza belog endosperma u proseku sastoji od 6,11% perikarpa, 79,24% endosperma i 14,65% klice. Prosečne vednosti hektolitarske mase, mase 1000 zrna, gustine, indeks flotacije, otpornoti na mlevenje i udela tvrde frakcije endosperma bile su 273,16 g, 778,60 kg/m3 , 1,28 g/cm3 , 27,70%, 12,85 s i 56,26%, redom. U proseku zrno hibrida belog endosperma sadrži 70,55% skroba, 9,38% proteina, 6,31% ulja, 2,31% sirove celuloze i 1,35% pepela. U odnosu na hibride žutog zrna ispitivani hibridi belog zrna su u proseku imali veći udeo klica i tvrde frakcije endosperma, viši sadržaj ulja i višu otpornost na melvenje, a manju masu 1000 zrna, indeks flotacija, masu klipa i masu zrna na klipu.White maize is maize with the endosperm of clear white colour, without the addition of the yellow pigment. The importance of white maize has changed over time in various countries and cultures. The comparison of the global distribution of white and yellow maize shows that the latter one has an absolutely dominant role in the world. The use of maize with the white endosperm has changed significantly in the last few decades. Its use in livestock feeding has practically ceased, while at the same time its use for obtaining special products for human consumption and in mill processing has increased. Therefore, the grain quality traits have become very important and they are given the same attention as the grain yield itself in the breeding and selection process. The aim of this study was to characterize white maize with respect to the morphological structure, different physical traits and basic chemical composition as a parameter of the use value and quality of grain. In addition, physical traits of ears were observed. Five ZP maize hybrids (three with white and two with yellow kernels of the FAO maturity groups 500 and 600) were selected for testing. The obtained results showed that the grain of observed white maize hybrids consisted, on average, of 6.11% pericarp, 79.24% endosperm and 14.65% germ. The average values of test weight, 1000-kernel weight, density, flotation index, milling response and the proportion of hard endosperm fractions amounted to 273.16 g, 778.60 kg/m3 , 1.28 g/cm3 , 27.70%, 12.85 s and 56.26%, respectively. On average, the grain of white hybrids contains 70.55% starch, 9.38% proteins, 6.31% oil, 2.31% crude fibres and 1.35% ash. Compared to yellow hybrids, the observed white hybrids had on average a higher proportion of germs and hard endosperm fraction, higher oil content and higher milling resistance, while 1000-kernel weight, flotation index, ear weight and kernel weight on the ear were lower