Udjeli bisfenola A (BPA) određeni su u sedimentu skupljenom na 35 postaja na Jadranu (kanali, estuarij, zaljevi, otvoreno more i luke) te u suspendiranoj tvari skupljenoj u Kaštelanskom zaljevu u ...periodu od 1999. do 2014. godine. U sedimentima je određen i granulometrijski sastav te maseni udjeli organske tvari i organskog ugljika. Maseni udjeli BPA su u sedimentu bili u rasponu od 1,05 g kg-1 do 69,99 g kg-1, a u suspendiranoj tvari od 1,84 g kg-1 do 103,06 g kg-1. Najviši maseni udio BPA određen je na postajama izloženim antropogenim utjecajima: u Kaštelanskom zaljevu, u luci Split te u području Bakarskog zaljeva i estuarija Krke. Analizom mjesečne raspodjele udjela BPA utvrđeno je da nema izraženih sezonskih oscilacija udjela BPA u sedimentu kao ni u suspendiranoj tvari. Usporedba rezultata analize BPA u sedimentu kroz duže razdoblje na većini je postaja pokazala porast masenih udjela BPA. Istraživanje je pokazalo da ne nepostoji direktna veza između sitnozrnate frakcije u sedimentu i udjela BPA, kako je bilo pretpostavljeno u hipotezi disertacije, a slijedom uobičajene povezanosti između udjela organske tvari, organskog ugljika, fosfora i frakcije silta ili gline. Razlog je vjerojatno potpuno drukčije porijeklo BPA i kemija BPA u sedimentu koja je bitno različita od ciklusa biogenih elemenata u morskom ekosustavu.
BPA mass fractions were determined in the sediments of 35 sites in the Adriatic Sea (channels, bays, open sea and city harbours) as well as in the suspended matter at the Kaštela Bay during 1999 to 2014 period. Sediment granulometric composition and content of organic matter and organic carbon were also analyzed. Mass fractions of BPA in sediments ranged between 1,05 g kg-1 and 69,99 g kg-1, and in suspended matter between 1,84 g kg-1 and 103,06 g kg-1. The highest BPA mass fractions were found in areas under anthropogenic impacts: in Kaštela Bay, Split city harbour, Bakar Bay and Krka River estuary. Monthly analysis of BPA distribution indicated no seasonal oscilations of BPA mass fractions in sediments and suspended matter. Comparison of results of BPA analysis during a longer period indicated an increase in BPA mass fractions in sediments at the majority of sampling sites. The research revealed the lack of a direct link between the fine grain fractions in the sediment and the mass fractions of BPA, as has been assumed in the hypothesis of the dissertation following the usual relationship between the proportion of organic matter, organic carbon, phosphorus and fractions of silt or clay. The reason is probably completely different origin of BPA and its chemistry in the sediment that is significantly different from the cycle of biogenic elements in the marine ecosystem.
Biginellijevom reakcijom, pripravljeni su razliĉito supstituirani derivati 3,4-dihidropirimidinona. Koristeći modelni derivat 124-I-b provedena su opsežna preliminarna ispitivanja u svrhu pronalaska ...odgovarajućih uvjeta aromatizacije sintetiziranih derivata. Opseg preliminarnih ispitivanja potkrepljuje literaturno poznatu ĉinjenicu kako se ovaj tip spojeva vrlo teško aromatizira. Rezultat istraţivanja u sklopu ove doktorske disertacije urodio je ĉetirima novim, do sad nepoznatim metodama aromatizacije 3,4-dihidropirimidinona. Efikasna, brza i selektivna metoda aromatizacije razvijena je uz molekularni jod i kalijev t-butoksid u suhom tetrahidrofuranu pri sobnoj temperaturi (konverzija 80 % - 100 %). Ispitan je i predloţen mehanizam aromatizacije koji upućuje na nastanak t-butilhipojodita kao aktivne vrste pri reakciji aromatizacije. Aromatizacija 3,4-dihidropirimidinona uz t-butilhidro-peroksid, molekularni jod i kalijev t-butoksid u t-butilacetatu, pri temperaturi povrata otapala, modificirana je, katalitiĉka verzija prethodno opisane metode ĉiji je mehanizam dehidrogenacije također predloţen. Zabilježena je konverzija reaktanata u produkte od vrlo visokih 98 % - 100 %. Niz supstituiranih derivata oksidiran je i efikasnom metodom uz t-butilhidroperoksid i kalijev hidroksid uz kalijev jodid kao katalizator. Reakcije su provedene u metanolu pri sobnoj temperaturi (konverzija 98 % - 100 %). Derivati 4-aril-pirimidin-2(1H)-ona dehidrogenirani su u odgovarajuće 4-aril-pirimidin-one metodom uz tetracijanoetilen u acetonitrilu pri povišenoj temperaturi. Aromatizacijom razliĉito supstituiranih derivata ovom metodom postignuta je maksimalna konverzija reaktanata u produkte (100 %). U završnoj fazi istraživanja provedena je i vezana sinteza prva tri koraka pri sintezi rosuvastatin kalcija na 17 razliĉito supstituiranih derivata 3,4-dihidropirimidinona. Ova sinteza ukljuĉuje aromatizaciju 3,4-dihidropirimidinona, aktivaciju dobivenog pirimidinona na položaju 2 azaheterocikliĉke jezgre te reakciju supstitucije tako pripremljenog produkta s odgovarajućim nukleofilom. Sva tri stupnja nadogradnje provedena su u jednoj reakcijskoj tikvici, bez izolacije međuprodukata, uz iskorištenje od 12 % - 71 %.
Differently substituted 3,4-dihydropyrimidinones were prepared using a three component Biginelli reaction. By using a model compound 124-I-b, extensive preliminary research was done in order to find a new appropriate 3,4-dihydropyrimidinone aromatization method. A wide range of reaction conditions, reagents, catalysts and solvents were examined. The scope of the preliminary examination supports the literature known fact that this kinds of compounds are very difficult to be aromatized. The research in the context of this PhD thesis has resulted in four new, so far unknown methods of 3,4-dihydropyrimidinone aromatization. Efficient, rapid and selective aromatization method was developed using molecular iodine and potassium t-butoxide in dry tetrahydrofuran at room temperature (conversion 80 % - 100 %). 3,4-Dihydropyrimidinone aromatization mechanism was proposed. It includes the formation of t-butil hypoiodite as an active species during aromatization. The second aromatization method is catalytic modification of the previously described method - aromatization of 3,4-dihydropyrimidinones using t-butyl hydroperoxide, molecular iodine and potassium t-butoxide in t-butyl acetate at reflux temperature (conversion 98 % - 100 %). The series of differently substituted derivatives were oxidized using on efficient method that includes t-butyl hydroperoxide as an oxidant, potassium hydroxide as a base and potassium iodide as a catalyst. Reactions were carried out in methanol at room temperature (conversion 98 % - 100 %). In the last aromatization method, the 4-aryl-pyrimidin-2(1H)-one derivatives were dehydrogenated to the corresponding 4-aryl-pyrimidine-ones using tetracyanoethylene in acetonitrile at elevated temperatures (conversion 100 %). The final stage was one pot synthesis of the first three steps in the synthesis of rosuvastatin calcium. This synthesis includes 3,4-dihydropyrimidinone aromatization, the activation of dehydrogenated product and a substitution reaction with an appropriate nucleophile. All three stages were carried out in a single reaction flask without isolation of intermediates. The corresponding products were obtained in a yield of 12 % - 71 %, depending on the derivative.
Within this thesis several proteins from H. pylori, important for survival of the bacterium, were structurally characterized (HpFlgD, CrdA, HP1026). Crystal structure of the truncated form of the ...HpFlgD protein revealed that spatial orientation of the two domains differs from that of the homologous FlgD family members. This fact together with the observation that truncated HpFlgD assembles into tetramers, both in the solution and in the crystal form, strongly suggests that significant differences exist in the molecular organization of the flagella in different bacterial species. It was shown that incubation of the putative copper binding CrdA protein with Cu2+ ions favours formation of monomeric species in solution and that CrdA binds Cu2+ with very low affinity which is a property of copper trafficking proteins. Functional assays of the HP1026 protein demonstrated for the first time its ATPase activity. While proteins that belong to the class of AAA+ proteins usually form hexamers, HP1026 was found to form dimers.
Within this thesis several proteins from H. pylori, important for survival of the bacterium, were structurally characterized (HpFlgD, CrdA, HP1026). Crystal structure of the truncated form of the HpFlgD protein revealed that spatial orientation of the two domains differs from that of the homologous FlgD family members. This fact together with the observation that truncated HpFlgD assembles into tetramers, both in the solution and in the crystal form, strongly suggests that significant differences exist in the molecular organization of the flagella in different bacterial species. It was shown that incubation of the putative copper binding CrdA protein with Cu2+ ions favours formation of monomeric species in solution and that CrdA binds Cu2+ with very low affinity which is a property of copper trafficking proteins. Functional assays of the HP1026 protein demonstrated for the first time its ATPase activity. While proteins that belong to the class of AAA+ proteins usually form hexamers, HP1026 was found to form dimers.
U sklopu ove disertacije strukturno su okarakterizirani proteini iz bakterije H. pylori koji su važni za njezino preživljavanje (HpFlgD, CrdA, HP1026). Riješena kristalna struktura skraćenog proteina HpFlgD ukazala je na drugačiju međusobnu orijentaciju dviju domena nego što je nađeno u ostalim homolozima proteina FlgD. Također je pokazano da je skraćeni HpFlgD i u otopini i kristalu prisutan kao tetramer što ukazuje na značajnu razliku u molekularnoj organizaciji biča u različitih bakterijskih vrsta. Uočeno je da dodatak iona Cu2+ u otopinu CrdA, proteina koji pretpostavljeno veže bakrove ione, potiče stvaranje monomernih vrsta u otopini te da CrdA veže ione Cu2+ sa slabim afinitetom što je karakteristika proteina koji prenose bakrove ione. Funkcionalna karakterizacija proteina HP1026 je po prvi put demonstrirala da HP1026 obavlja ATPaznu aktivnost. Iako se proteni koji spadaju u skupinu AAA+ proteina najčešće udružuju kao heksameri, za HP1026 je pokazano da u otopini stvara dimerne vrste.
Rod Centaurea, porodica Asteracea, taksonomski je vrlo složen, a 80 od ukupno 400 do 700 vrsta nalazimo na području Republike Hrvatske. Cilj ovoga doktorskog rada bio je odrediti fitokemijski i ...citogenetski profil odabranih vrsta roda Centaurea: Centaurea ragusina, Centaurea rupestris i Centaurea solstitialis. Fitokemijski profil, određen kroz kemijski sastav izoliranih hlapljivih ulja, istražen je vezanim sustavom plinska kromatografija - masena spektrometrija. Citogenetski profil, određen kao veličina genoma i osnovni broj kromosoma istraživanih vrsta, istraživan je protočnom citometrijom i standardnim kariološkim metodama. Citogenetski profil fitokemijski proučavanih vrsta u skladu je s prethodnim istraživanjima, čime je utvrđena autentičnost istraživanih vrsta bez dvojbe prilikom botaničke determinacije. Dominantne su komponente hlapljivih ulja odabranih vrsta roda Centaurea neoksidirani i oksidirani seskviterpenski spojevi te neterpenske kiseline i ugljikovodici. Germakren D, -kariofilen i heksadekanska kiselina identificirani su u svim proučavanim eteričnim uljima. Izolirana hlapljiva ulja pokazuju slab antioksidacijski potencijal i slabu sposobnost inhibicije acetilkolinesteraze i butirilkolinesteraze kao i značajan antimikrobni potencijal.
The Centaurea genus, Asteraceae family, taxonomically is very complex. It contains 80 species from Croatia, of about 400 up to 700 in total. The aim of this doctoral thesis was to determine the phytochemical and cytogenetic profiles of selected Centaurea species: Centaurea ragusina, Centaurea rupestris and Centaurea solstitialis. Phytochemical profile, determined as chemical composition of isolated volatile oil, was assesed with associated gas chromatography-mass spectrometry. Cytogenetic profile, expressed as genome size and chromosome number, was assessed by flow cytometry and standard karyological methods. Cytogenetic profile of species selected for phytochemical research, is in accordance with previous research, which aproves authenticity of the studied taxa. Dominant components of volatile oils of Centaurea species are oxidized and nonoxidized sesquiterpenes, and nonterpene acids and hydrocarbons. Germacrene D, -caryophyllene and hexadecanoic acid are identified in all Centaurea volatile oils. Isolated volatile oil showed weak antioxidant potential and inhibiton of acetylcholinesterase and butyrylcholinesterase, as well as significant antimicrobial potential.
Poznato je da prirodni spoj trans-resveratrol (trans-3,5,4'-trihidroksistilben, ArOH) posjeduje izrazitu biološku aktivnost. Unatoč poznavanju mogućih mehanizama antioksidacijskog djelovanja kojima ...se pridjeljuje protektivna uloga ArOH u živim organizmima, o njegovim kemijskim svojstvima se malo zna. Cilj ove disertacije je istražiti kinetike i mehanizme reakcija ArOH s do sada neistraženim radikalima koji nastaju u uvjetima stanja oksidacijskog stresa. Ovi radikali i pobuđena stanja ArOH generirani su svjetlosnim pulsom koristeći rubinski i Nd:YAG laserski uređaj odnosno pulsom ubrzanih elektrona. Tranzijentnom apsorpcijskom spektroskopijom detektirane su intermedijerne vrste te određene konstante brzina reakcija ArOH s radikalima lokaliziranim na kisiku, ugljiku i sumporu odnosno s aril-ketonima u tripletnim stanjima. Reakcije su praćene na vremenskim skalama reda veličine 1061012 s u acetonitrilu i otopinama alkohol/voda. Budući da je poznato da su istraživani radikali odgovorni za poremećaje u odvijanju normalnih procesa u stanicama živih organizama, rezultati ovih istraživanja su originalan doprinos razumijevanju mehanizama i kinetike reakcija ArOH s biološki značajnim radikalima.
It is well known that natural compound trans-resveratrol (trans-3,5,4'-trihydroxystilbene) possesses significant biological activity. However, despite the knowledge of its possible antioxidant mechanisms which have a protective role in the living organisms, chemical properties of ArOH are less known. The main goal of this thesis is to investigate reaction kinetics and mechanisms of ArOH with so far unresearched free bioradicals which occur in the conditions of oxidative stress. These free radicals and ArOH excited states were generated with ruby or Nd:YAG laser flash or electron accelerator pulse. Short-lived intermediate species of ArOH and its reaction kinetics with oxygen, sulphur and carbon-centered radicals and aromatic carbonyl triplets were determined with transient absorption spectroscopy. Measurements were conducted at the 1061012 sec time scales in acetonitrile and solutions of water/alcohol. This research is original contribution to the understanding of the mechanism and reaction kinetics of ArOH antioxidant activity with biologically relevant free radicals under investigation which are known to be responsible for the malfunction of the normal processes in living cells.
U radu je opisan kemijski i mineralni sastav te je utvrđena starost i porijeklo tufova koji su tijekom
miocena taloženi na prostoru Sjevernohrvatskog bazena, smještenog u južnom dijelu Panonskog ...bazenskog
sustava. Osim toga, analiziran je fosilni sadržaj u naslagama iz neposredne podine i krovine tufa. Analizirani
tufovi s područja Banovine, Medvednice, Moslavine i Slavonije primarno su bili riolitnog do tefrifonolitnog
sastava, a naknadno su dijelom ili u potpunosti alterirani u smektite i heulandit. Vulkanska aktivnost najvećim
se dijelom odvijala tijekom sin-riftne faze razvoja bazena. Prema rezultatima datiranja 40Ar*/39Ar metodom
na sanidinima, najintenzivnija je bila u razdoblju od 17-14,4 Ma odnosno tijekom karpata, te donjeg i srednjeg
badena. Po prvi puta zabilježena je, znatno slabija, vulkanska aktivnost u postriftnoj fazi razvoja bazena,
krajem sarmata, prije oko 12 Ma. Prema klasifikacijskim dijagramima temeljenima na kemijskom sastavu
tufova, izvorište piroklastičnog materijala bio je aktivni kontinentalni rub koji je najvjerojatnije bio smješten
na prostoru Istočnih Karpata. Fosilna zajednica foraminifera, ostrakoda, nanoplanktona i palinomorfa
pokazala je da su tufovi stariji od 15,1 Ma taloženi u slatkovodnim ili bočatim jezerskim okolišima, a oni
datirani na 14,8 do 14,4 Ma u marinskim okolišima. Time je je marinska transgresija u Sjevernohrvatskom
bazenu, ranije uglavnom smještena na početak karpata, pomaknuta na približno 15 Ma, tj. na granicu donjeg
i srednjeg badena.
Tuffs have been deposited during the Miocene in the North Croatian Basin which is located in the
southern part of the Pannonian Basin System. In this thesis chemical and mineral composition of the tuffs as
well as their age and origin were determined. In addition, the fossil content was analyzed in the underlying
and overlying beds of the tuffs. Based on chemical composition tuffs have been classified as neutral
(tephriphonolite) to acid (riolite). In most tuffs volcanic glass was partially or completely altered to clay
minerals (smectite) or in some cases zeolites (heulandite). During the sin-rift phase of basin development
volcanic activity was at its peak. According to the results of the 40Ar*/39Ar dating on sanidine, the most
intensive period of volcanic activity was during the Karpatian and the Early and Middle Badenian (17 – 14.4
Ma). For the first time, the volcanic activity in the post-rift stage of the development of the basin has been
recorded at the end of Sarmatian ~ 12 Ma ago. Based on the content of immobile trace elements the source
of the pyroclastic material was placed on an active continental margin, most probably located in the Eastern
Carpathians area. The fossil assemblage of foraminifera, ostracods, nannoplankton and palinomorphs has
shown that the tuffs older than 15.1 Ma were deposited in freshwater or brackish lake environments, and
those dated from 14.8 to 14.4 Ma in marine environments. Older studies place the onset of the marine
sedimentation in Karpatian time, while this study suggests it should be moved to the Early/Middle Badenian
boundary.
U radu je opisan kemijski i mineralni sastav te je utvrđena starost i porijeklo tufova koji su tijekom
miocena taloženi na prostoru Sjevernohrvatskog bazena, smještenog u južnom dijelu Panonskog bazenskog
sustava. Osim toga, analiziran je fosilni sadržaj u naslagama iz neposredne podine i krovine tufa. Analizirani
tufovi s područja Banovine, Medvednice, Moslavine i Slavonije primarno su bili riolitnog do tefrifonolitnog
sastava, a naknadno su dijelom ili u potpunosti alterirani u smektite i heulandit. Vulkanska aktivnost najvećim
se dijelom odvijala tijekom sin-riftne faze razvoja bazena. Prema rezultatima datiranja 40Ar*/39Ar metodom
na sanidinima, najintenzivnija je bila u razdoblju od 17-14,4 Ma odnosno tijekom karpata, te donjeg i srednjeg
badena. Po prvi puta zabilježena je, znatno slabija, vulkanska aktivnost u postriftnoj fazi razvoja bazena,
krajem sarmata, prije oko 12 Ma. Prema klasifikacijskim dijagramima temeljenima na kemijskom sastavu
tufova, izvorište piroklastičnog materijala bio je aktivni kontinentalni rub koji je najvjerojatnije bio smješten
na prostoru Istočnih Karpata. Fosilna zajednica foraminifera, ostrakoda, nanoplanktona i palinomorfa
pokazala je da su tufovi stariji od 15,1 Ma taloženi u slatkovodnim ili bočatim jezerskim okolišima, a oni
datirani na 14,8 do 14,4 Ma u marinskim okolišima. Time je je marinska transgresija u Sjevernohrvatskom
bazenu, ranije uglavnom smještena na početak karpata, pomaknuta na približno 15 Ma, tj. na granicu donjeg
i srednjeg badena.
Razvijena je multirezidualna metoda za određivanje 25 pesticida u vinima plinskom kromatografijom vezanom sa spektrometrijom masa. Optimirana je ekstrakcija na čvrstoj fazi uz sorbens OASIS HLB te ...postupak ekstrakcije QuEChERS s težištem na optimizaciji koncentracije dodanih soli radi podešavanja raspodjele analita između dviju faza. Za svaki postupak priprave uzorka provedena je validacija za crno i bijelo vino kao dvije zasebne matrice uzorka. Granice određivanja pesticida za oba postupka bile su u rasponu od 0,01 g L1 do 250 g L-1. Preciznost, izražena kao relativna standardna devijacija, bila je <20 %, dok je točnost, izražena kao analitički povrat, za većinu pesticida bila u rasponu od 70 % do 120 %. Ispitan je utjecaj matrice na određivanje pesticida pri čemu je izračunata djelotvornost postupaka priprave uzorka. U okviru validacije metoda procijenjena je mjerna nesigurnost koja je bila <50 % za većinu pesticida. Predloženim analitičkim postupcima analizirana su 63 uzorka različitih vina da bi se dobio prvi uvid u koncentracije ostataka pesticida u vinima s područja Hrvatske.
A new multiresidue method was developed for determination of 25 pesticides in wines by gas chromatography mass spectrometry. Two sample preparation procedures were optimized; solid phase extraction using OASIS HLB and QuEChERS procedure, where salt concentrations were optimised in order to adjust the distribution of pesticides between two immiscible phases. Method validation, including uncertainty estimation (<50 % for most pesticides), was performed independently for red and white wine as two different matrices and for each sample preparation procedure. Limits of quantification were between 0,01 g L-1 and 250 g L-1. The recoveries of most pesticides were between 70 % and 120 % with relative standard deviations <20 %. The matrix effect was investigated and the quality of sample preparation procedures has been evaluated in terms of extraction efficiency. The proposed analytical procedures were applied to 63 Croatian wine samples of different varieties in order to provide the first insight into pesticide residue concentrations in Croatian wines.
Reakcijom srebrova(I) nitrata s mono- i dihalogen derivatima piridina u molarnom omjeru 1 : 2 u smjesi vode i alkohola priređeno je 12 novih kompleksa srebra(I) opće formule Ag(NO3)(Xnpy)2, X = Cl, ...Br, I; n = 1 – 2. Pripravljeni kompleksni spojevi identificirani su pomoću elementne analize, dok je njihova struktura u otopini okarakterizirana tehnikama višenuklearne spektroskopije NMR (1H, 13C, 15N, 109Ag) i spektrometrije masa. Kompleksi su u čvrstom stanju okarakterizirani spektroskopijom IR, a kristalna i molekulska struktura im je određena metodama rentgenske strukturne analize.
Molekule liganda su u svim kompleksima na srebrov(I) ion vezane preko atoma dušika piridinskog prstena. U koordinacijskoj sferi srebra(I) dokazan je i nitratni ion koji ovisno o načinu koordiniranja na srebro omogućava stvaranje koordinacijskih polimera ili supramolekulskih struktura. Koordinacijski broj srebra kod sintetiziranih spojeva varira između tri, četiri, pet ili šest i to čak ponegdje i unutar istog spoja. Pored kovalentnih veza, Ag–N i Ag–O, u strukturama su pronađene i nekovalentne interakcije (vodikove i halogenske veze te π···π interakcije) koje pridonose konačnoj dimenzionalnosti spoja. Slaba veza Ag–Ag otkrivena je u kompleksu s 3-Ipy kao ligandom. Priređeni spojevi pokazuju bolju antibakterijsku aktivnost u uvjetima in vitro spram Gram-negativnih nego spram Gram-pozitivnih bakterijskih vrsta.
Twelve 1:2 complexes of silver(I) nitrate with mono- and dihalopyridine of the general formula Ag(NO3)(Xnpy)2, X = Cl, Br, I; n = 1–2, were prepared by reaction of AgNO3 and corresponding pyridine derivative in water-alcohol solution. All synthesized complexes were identified by elemental analysis and characterized in solution by multinuclear NMR spectroscopy (1H, 13C, 15N, 109Ag) and mass spectrometry. In solid state the complexes were characterized by IR spectroscopy, while their crystal and molecular structures were revealed by single crystal X-ray analysis.
It was established that in all complexes, besides pyridine nitrogen atoms, the oxygen atoms belonging to nitrate ion are also coordinated to silver ion thus providing not only different coordination numbers of Ag(I) which vary from three, four, five and six but also a formation of coordination polymers or supramolecular structures. It is interesting that in the molecule of one complex, which is dinuclear, there are even two differently coordinated silver ions (3, 4). Beside covalent Ag–N and Ag–O bonds present in complex molecules, there are various non-covalent interactions such as hydrogen bonding, halogen bonds and halogen-halogen interactions thus contributing to final dimensionality. Moreover, a weak Ag–Ag bonding was determined in complex with 3-Ipy as a ligand. In vitro tests of all complexes gave better antibacterial activity against Gram-negative than Gram-positive strains.
Korištenjem računalnih metoda molekulskog modeliranja proučavane su konformacijske
promjene u aktivnom mjestu acetilkolinesteraze (AChE; EC 3.1.1.7) nakon vezanja raznih
liganada te su definirane ...strukturne karakteristike učinkovitih oksimskih reaktivatora AChE
inhibirane živčanim bojnim otrovima kao i smjernice za njihovu sintezu. Pripravljena su četiri
nova kiralna oksima iz skupine N-supstituiranih 2-hidroksiiminoacetamida polazeći od
racemičnog 1-fenilprop-2-en-1-amina pripravljenog iz 3-fenilprop-2-en-1-ola. Enantiomeri
oksima odijeljeni su tekućinskom kromatografijom visoke djelotvornosti na polisaharidnim
kiralnim nepokretnim fazama. Novi oksimi ispitani su kao inhibitori AChE i
butirilkolinesteraze (BChE; EC 3.1.1.8) i kao reaktivatori kolinesteraza inhibiranih tabunom,
ciklosarinom, sarinom i VX-om. Svi oksimi reverzibilno inihibiraju oba enzima s konstantom
inhibicije (KI) u mikromolarnom području. Oba enzima pokazuju najveći afinitet prema N-(3-
(4-((2-metilimidazol-1-il)metil)-1,2,3-triazol-1-il)-1-fenilpropil)-2-hidroksiiminoacetamidu
prema kojem BChE pokazuje značajnu selektivnost i stereoselektivnost. Isti oksim jedini se
pokazao učinkovitijim od vodećih oksima opisanih u literaturi i to u slučaju BChE inhibirane
ciklosarinom. Molekulskim pristajanjem utvrđeno je da na razlike u smještavanju novih
oksima u AChE i BChE najviše utječu razlike u aminokiselinama na pozicijama Tyr72,
Tyr124, Phe297 i Tyr337 u aktivnom mjestu AChE.
Using computational methods of molecular modelling conformational changes in the active
site of acetylcholinesterase (AChE; EC 3.1.1.7) upon binding of various ligands were
investigated and structural characteristics of efficient oxime reactivators of AChE inhibited
with warfare nerve agents and gudelines for their synthesis were defined. Four new chiral
oxime reactivators from N-substituted 2-hydroxiiminoacetamide group were prepared starting
from racemic 1-phenyl-allylamine prepared from cinnamyl alcohol. Enantiomers of oximes
were separated using high performance liquid chromatography on polysaharidic chiral
stationary phases. New oximes were tested for inhibition of AChE and butyrylcholinesterase
(BChE; EC 3.1.1.8) and reactivation of cholinesterases inhibited with tabun, cyclosarin, sarin
and VX. New oximes reversibly inhibit both enzymes with inhibition constant (KI) in the
micromolar range. Both enzymes showe greatest affinity toward 2-hydroxyimino-N-(3-(4-((2-
methylimidazol-1-yl)methyl)-1,2,3-triazol-1-yl)-1-phenylpropyl)acetamide towards which
BChE displays significant selectivity and stereoselectivity. Only this oxime showed greater
reactivation efficiency than the reference oximes described in literature in the case of BChE
inhibited with cyclosarin. Molecular docking studies concluded that differences in binding of
new oximes in AChE and BChE largely result from differences in the amino acids at the
position of Tyr72, Tyr124, Phe297 and Tyr337 in the AChE active site.
Izvršena su strukturna istraživanja uzoraka AMn2O4 (A= Co, Zn, Ni, Cd, Cu) s ciljem određivanja utjecaja uvjeta sinteze na specifične značajke spinelnih struktura. Nađeno je da svi uzorci spinelne ...strukture pri čemu CoMn2O4, ZnMn2O4 i CdMn2O4 kristaliziraju u tetragonskom, a NiMn2O4 i CuMn2O4 u kubnom sustavu. Parametri inverzije za CoMn2O4 i CdMn2O4 rastu s porastom temperature termičke obrade (25500 oC). Parametar inverzije ZnMn2O4 povećava se s porastom temperature do 300 oC nakon čega se inverzija smanjuje. Struktura NiMn2O4 ne ovisi o temperaturi termičke obrade. Spoj CuMn2O4 nije moguće prirediti bez prisutstva nečistoća neovisno o temperaturi termičke obrade. Provedena su i elektrokemijska mjerenja; ustanovljeno je da najbolje ponašanje pokazuje CoMn2O4. Porast temperature termičke obrade uzrokovao je i rast čestica. Uzorak s najvećom veličinom čestica koji pokazuje najviši specifični kapaciteta, najbolje elektrokemijsko ponašanje te izrazito visoku održivost kapaciteta od 104 % nakon 1000 ciklusa punjenja i pražnjenja.
Structural studies on AMn2O4 (A = Co, Zn, Ni, Cd, Cu) have been performed in order to determine the influence of the synthesis conditions on the specific features of spinel structure, primarily on the inversion parameter. It was found that all samples belong to the spinel structure type; CoMn2O4, ZnMn2O4 and CdMn2O4 are tetragonal while NiMn2O4 and CuMn2O4 crystallize in the cubic system. The inversion parameter of CoMn2O4 and CdMn2O4 increases with increasing temperature (25500 C) while inversion in ZnMn2O4 increases with increase of temperature up to 300 C and decreases afterwards. Structure of NiMn2O4 does not depend on the heat treatment. Phase purity for CuMn2O4 was not achieved regardless of the temperature of the heat treatment. Electrochemical measurements were carried out for all samples; CoMn2O4 showed the best electrochemical performance. The increase in heat treatment caused pronounced particle growth. The sample with the largest particle size showed the highest specific capacity, best electrochemical cycling and extremely high capacity retention (104 % after 1000 cycles).
