Revisited Mechanism of Reaction between a Model Lysine Amino Acid Side Chain and 4-Hydroxynonenal in Different Solvent Environments

We revisit the reaction mechanism of reaction between model lysine side chain and reactive aldehyde 4-hydroxynonenal in different solvents with increasing water content. We show by model organic reactions and qualitative spectrometric analysis that non-polar pyrrole adduct is dominantly formed in non-aqueous solvents dichloromethane and acetonitrile. On the other hand, in aqueous acetonitrile and neat water, other polar products are also isolated including Michael adducts, hemiacetal adducts and pyridinium salt adducts, at the same time decreasing the ratio of non-polar products vs polar products. The experiments are supported by detailed quantum chemical calculations of the reaction mechanism with different computational setups showing that the pyrrole adduct is the most thermodynamically stable product compared to Michael adducts and hemiacetal adducts and also indicating that water molecules released along the reaction pathway are catalyzing reaction steps involving proton transfer. Finally, we also identify the mechanism of the pyridinium salt adduct which is formed only in aqueous solutions

MIRJANA ECKERT-MAKSIĆ – Biography and Contributions

Biografija Mirjane Eckert MaksićBiography of Mirjana Eckert Maksi

Multireference Configuration Interaction Methods – An Application to the Valence Isomerism in Cyclobutadieno-p-benzoquinone and its Diprotonated Form

Multireference averaged quadratic coupled cluster (MR-AQCC) calculations for cyclobutadieno-p-benzoquinone indicate that valence bond isomers 1a and 1b can exist as distinct species. The energy barrier height for their interconversion are 4.6 and 4.5 kcal mol−1, respectively, what is by ca. 2 kcal mol−1 lower than in the parent cyclobutadiene, implying that they could perhaps exist only under extreme conditions, namely at very low temperatures. For double protonated cyclobutadieno-p-benzoquinone, the CASSCF calculations erroneously predict existence of two valence isomers, 2a and 2b, whereas the MR-AQCC calculations reveal that geometry of the double protonated species could be best described by structure 2b. This nicely illustrates the crucial role of dynamic correlation and the need for using a highly-correlated theoretical method including geometry optimization in studied molecules

DETERMINATION OF THE CONCENTRATION OF NICOTIN AND ITS METABOLITES IN THE URINE SAMPLE OF PASSIVE SMOKERS

Ciljevi ispitivanja: Cilj ovog eksperimentalnog rada je bio je pmomoću GC-MS metode kvantitativno odrediti koncentracije nikotina i kotinina i trans-3- hdroksikotinina u biološkim uzorcima urina dobrovoljnih ispitanika prije i poslje odlaksa u noćni klub u kojem je dozvoljeno pušenje. Materijal i metode: U straživanju je sudjelovalo 22 ispitanika, od toga 7 muškaraca i 15 žena. Biološki uzorci urina nepoznath koncentracija nikotina i metabolita pripremljen za analizu ekstrakcijskom metodom tekuće-tekuće (LLE).Za analizu koristili smo GC-MS. Rezultati: Svi uzorci bili su pozitivni na nikotin i metabolite. Srednja vrjednost nikotina, kotinina i 3-OHK prije izloženosti u noćnom klubu kod nepušača iznosila je 8,197 ng/mL, 28,372 ng/mL, 12,303 ng/mL kod žena i 11,235 ng/mL, 25,763 ng/mL, 3,673 ng/mL kod muškaraca. Srednja vrijednost nakon izloženosti iznosila je: 123,373 ng/mL, 56,544 ng/mL, 41,501 ng/mL kod žena i 21,366 ng/mL, 65,234 ng/mL, 14,941 ng/mL kod muškaraca. Zaključci: Koncentracije nikotina i metabolita kod nepušača prije izloženosti bile su značajn manje neko nakon izloženosti. Razine nikotina i metabolita kod pušača značajn su veće nego li kod nepušaća. S obzirom a dužinu izloženost porast koncentracija kod konobara, nepušača za nikotin, kotinin i 3-OHK veći je neko kod muških ispitanika koji su boravili u klubu kao posjetitelji.Aims of the study: The purpose of this experimental work was to quantitatively determine the concentrations of nicotine and cotinine and trans-3-hydroxycotinine in biological urine samples from voluntary subjects before and after their visit to a nightclub in which smoking was allowed, by using the GC-MS method. Material and methods: Twenty-two subjects participated in the research, including 7 men and 15 women. Biological urine samples of unknown nicotine and metabolite concentrations were prepared for analysis by the liquid-liquid extraction (LLE) method. For analysis, we used the GC-MS method. Results: All samples were positive for nicotine metabolites. The mean value of nicotine, cotinine and 3-OHK before exposure at a nightclub in non-smokers was 8,197 ng / mL, 28,372 ng / mL, 12,303 ng / mL in women and 11,235 ng / mL, 25,763 ng / mL, 3,673 ng / mL in men. Mean post-exposure values were: 123,373 ng / mL, 56,544 ng / mL, 41,501 ng / mL in women and 21,366 ng / mL, 65,234 ng / mL, 14,941 ng / mL in men. Conclusions: Concentrations of nicotine and metabolites in non-smokers before exposure were significantly lower than after exposure. The levels of nicotine and metabolites in smokers are significantly higher than in non-smokers. Considering the length of exposure, the increase in concentrations of nicotine, cotinine, and 3-OHK in non-smoker waiters was higher than in male respondents who stayed in the club as visitors

Proton Affinities of Didehydroporphyrin and Subporphyrin in Ground and Excited States Obtained by Quantum Chemical Calculations

Quantum-chemical calculations were used to investigate molecular and electronic properties of porphyrin and subporphyrin. Their basicities were estimated in ground and excited states. It was found that multiple proton - nitrogen lone-pair coordination plays an important role in acid/base properties of the studied molecules. Lone pair-lone pair interactions in didehydroporphyrin and energetic stabilization of its protonated form lead to the increase of a proton affinity compared to porphyrin by 18 kcal mol(-1). A planarization of the protonated (dehydroporphyrin) structure leads to the complete reversal of the pi-electron ring currents indicating aromaticity of the protonated form. On the other hand, calculations indicate that subporphyrin is slightly (by 5 kcal mol(-1)) more basic than porphyrin, which was explained by non-planar geometry, imposed by smaller ring size

Influence of HER-2/neu gene polymorphism on monoclonal antibody trastuzumab induced cardiotoxicity

Malobrojna dosadašnja istraživanja pokazala su dvojbene rezultate utjecaja polimorfizma gena HER-2/neu na kardiotoksičnost uzrokovanu monoklonskim protutijelom trastuzumabom. Obzirom na izuzetno važan biljeg u onkologiji i mogući čimbenik rizika srčanog oštećenja, nametnula se potreba ovakvog istraživanja. U istraživanje su uključene ispitanice adjuvantno liječene trastuzumabom zbog HER2 pozitivnog ranog raka dojke (n=177). Ispitanice su podijeljenje u dvije grupe: grupa A (n=99) kod kojih nije došlo do kardiotoksičnosti tijekom liječenja trastuzumabom i grupa B (n=78) kod kojih je došlo do razvoja kardiotoksičnosti. Istraženi su rizični čimbenici kao i osobitosti same kardiotoksičnosti, vrijeme pojavnosti i oporavka te reverzibilnost. Svim ispitanicama je lančanom reakcijom polimeraze određen polimorfizam gena HER-2/neu na kodonu 655 [Ile655Val] te distribucija genotipa Ile/Val, Ile/Ile i Val/Val. Praćenje srčane funkcije ehokardiografijom bilo je u skladu s usvojenim smjernicama praćenja. Iz rezultata dobivenih usporedbom grupa A i B nije nađena povezanost između pojedinog genotipa HER-2/neu i pojave kardiotoksičnosti.A few studies so far have shown doubtful results on influence of HER-2/ neu gene polymorphism on cardiotoxicity caused by monoclonal antibody trastuzumab. Remarkable importance of this marker in oncology and its place as a possible risk factor for cardial damage, imposed the need for this kind of research. The study included patients adjuvantly treated with trastuzumab for HER2 positive breast cancer (n = 177). Subjects were divided into two groups: group A (n = 99), which did not experience cardiotoxicity during treatment with trastuzumab and group B (n = 78) which did. Risk factors were investigated as well as the characteristics of cardiotoxicity, time of occurrence and recovery, and reversibility. Polymorphism of the HER-2/ neu gene on codon 655 [Ile655Val] and Ile/Val, Ile/Ile and Val/Val genotype distribution was determined by polimerase chain reaction in all patients. Heart function monitoring with echocardiography was consistent with the adopted monitoring guidelines. From the results obtained by comparing groups A and B, no correlation was found between HER-2/neu genotype and cardiotoxicity

Human Molar Crown Traits in Croatian Medieval and Contemporary Populations

Kosti i zubi iznimno su vrijedan i koristan izvor informacija u bioarheološkim istraživanjima, jer godinama mogu ostati sačuvani u nepromijenjenom obliku. Morfološke osobitosti zuba često su pomogle da se objasne određeni povijesni problemi koji se nalaze u središtu zanimanja antropoloških istraživanja. Svrha rada: U istraživanju smo željeli usporediti morfološke osobitosti kruna humanih kutnjaka u srednjovjekovnoj i suvremenoj hrvatskoj populaciji. Materijali i metode: Za analizu su bila odabrana 252 humana kutnjaka arheološkog (172) i recentnog (80) podrijetla. Kod gornjih kutnjaka određivala se frekvencija metakonusa, hipokonusa, metakonulusa, parastila i Carabellijeva svojstva. Na donjima je zabilježena frekvencija pojavljivanja prednje jamice, središnjeg trokutastog grebena, fisurnog crteža, zakrivljenog nabora, broja kvržica na kutnjacima, protostilida, distalnog trokutastog grebena te pete, šeste i sedme kvržice. Stupanj izraženosti svakog morfološkog obilježja bio je razvrstan prema sustavu ASUDAS (Dentalni antropološki sustav Državnoga sveučilišta Arizone). Analizom i usporedbom zuba arheološkog i suvremenog podrijetla ustanovljene su velike statističke razlike. Rezultati: Na gornjim kutnjacima uočene su razlike u frekvenciji pojavljivanja hipokonusa i metakonulusa, a na donjima je zapažena razlika u frekvenciji pojavljivanja prednje jamice i pete kvržice. Zaključak: Uočene razlike nije moguće objasniti samo istrošenošću zuba, jer su se u istraživanju stručnjaci koristili zubima s niskim stupnjem abrazije. Dodatna objašnjenja treba potražiti među dostupnim povijesnim i arheološkim podacima, jer su se u srednjovjekovnom razdoblju vodili mnogobrojni ratovi, pa su česte bile i migracije stanovništva.Bones and teeth represent an exceptionally valuable and useful source of information for bioarchaeological research, since they may remain unaltered for a long period of time. The morphological characteristics of teeth are often used to explain certain historical problems which are the focus of interest in anthropological research. Purpose: the aim of this study was to compare morphological particularities of human molar crown traits in Croatian medieval and contemporary populations. Materials and methods: This research was conducted on 252 human molars, both of archeological (172) and of recent (80) origin. Upper molars were studied to determine the frequency of occurrence of: metaconus, hypoconus, metaconulus, parastyle and Carabelli’s trait. Lower molars were studied to register the frequency of occurrence of: anterior fovea, mid trigonid crest, groove pattern, deflecting wrinkle, molar cusp number, protostylid, distal accessory ridge, cusp 5, cusp 6 and cusp 7. Each morphological feature’s degree of expression was classified according to Arizona State University Dental Anthropological System. Statistically significant differences were established through analysis and comparison of these teeth of archeological and recent origin. Results: on the upper molars there were differences in the frequency of the occurrence of the hypoconus and metaconulus. On the lower molars there were differences in the frequency of the occurrence of the, anterior fovea and 5th cusp. Conclusion: these differences can’t be simply explained by wear, since the teeth selected for research all displayed a low degree of abrasion. Additional explanation should be sought among available historical and archeological data, since the medieval period was marked by numerous wars and population migration

Islamic State: the role of internet and social networks in radicalization of Western

Novi mediji, posebice društvene mreže poput Facebooka i Twittera, pokazali su se kao jedno od glavnih oružja Islamske države, terorističke organizacije koja je putem njih uspješno širila ideologiju radikalnog islamizma i regrutirala nove članove. Rezultat toga je i fenomen odlaska velikog broja mladića i djevojaka iz Europe u Siriju kako bi se borili na strani Islamske države, što potvrđuje i podatak od oko 40 tisuća pojedinaca, među kojima je i značajan broj mladih žena koje su u tom razdoblju odlučile svoj dom zamijeniti onim unutar organizacije. Zauzvrat im je bio obećan život u pravom islamskom kalifatu, u kojem slobodno mogu prakticirati svoju vjeru. Uloga žena u izgradnji Islamske države pokazala se strateški važnom zbog čega ih se putem propagande dodatno motiviralo na odlazak iz domicilnih zemalja. U radu su prezentirani ideološki, vjerski i osobni razlozi koji stoje iza odlaska žena na teritorij pod nazorom Islamske države te analiza propagande koju su pripadnice Islamske države širile na društvenim mrežama i putem službenih časopisa „Dabiq“ i „Rumiyah“

Islamic State: the role of internet and social networks in radicalization of Western

Novi mediji, posebice društvene mreže poput Facebooka i Twittera, pokazali su se kao jedno od glavnih oružja Islamske države, terorističke organizacije koja je putem njih uspješno širila ideologiju radikalnog islamizma i regrutirala nove članove. Rezultat toga je i fenomen odlaska velikog broja mladića i djevojaka iz Europe u Siriju kako bi se borili na strani Islamske države, što potvrđuje i podatak od oko 40 tisuća pojedinaca, među kojima je i značajan broj mladih žena koje su u tom razdoblju odlučile svoj dom zamijeniti onim unutar organizacije. Zauzvrat im je bio obećan život u pravom islamskom kalifatu, u kojem slobodno mogu prakticirati svoju vjeru. Uloga žena u izgradnji Islamske države pokazala se strateški važnom zbog čega ih se putem propagande dodatno motiviralo na odlazak iz domicilnih zemalja. U radu su prezentirani ideološki, vjerski i osobni razlozi koji stoje iza odlaska žena na teritorij pod nazorom Islamske države te analiza propagande koju su pripadnice Islamske države širile na društvenim mrežama i putem službenih časopisa „Dabiq“ i „Rumiyah“