Kinetic Study of the Pyridine-Catalyzed Selenolactonization of 4-Pentenoic Acid

© 2020, Springer Science+Business Media, LLC, part of Springer Nature. Abstract: The kinetics and mechanism of the pyridine-catalyzed cyclofunctionalization of 4-pentenoic acid by means of PhSeX (X = Cl, Br) have been investigated spectrophotometrically, under pseudo-first order reaction conditions. The influence of the reaction temperature, the type of cyclization reagent and used catalyst on the reaction rate and mechanism was examined. The obtained data have showed that rate constants go on increasing as the temperatures go up and with use of PhSeCl as reagent. Also, the reaction rate is directly depended on the type of the catalyst used—stronger bases with higher tendency for hydrogen bond formation (DN) are promoting reaction in more efficient way. Graphic Abstract: [Figure not available: see fulltext.]

Lifeline Method in Research of Adult Learning and Career: Towards the Quality

The paper discusses results of the research conducted with double aim. First aim was to examine the relation between education and learning and career of adults, through research of key periods in line of career, line of education and learning, and research of overlaps and gaps between these lines. All these periods are indicators of certain quality of adult education and learning. Second goal was examination of the quality of the lifeli- ne method which is used in this empirical research, a method known for its application in various career guidance and counseling interventions but with insufficient use in sci- entific research. The research results show that the line of career is saturated with career transition periods, while the line of education and learning is dominated by formal edu- cation. Education is often perceived as important for entry into the profession, but is not perceived as support in critical points in career

Obrazovanje i karijerni razvoj odraslih – Istraživanje kvaliteta

U ovom radu razmatra se kvalitet obrazovanja posmatran kao podrška karijernom razvoju odraslih. Osnova za razmatranje kvaliteta obrazovanja leži u rezultatima istraživanja sprovedenog sa ciljem ispitivanja „putanja“ obrazovanja i učenja i „putanja“ karijere, a primenom lifeline metoda. Analiziranjem putanja obrazovanja i putanja karijere, uočava se da postoje određene tačke ukrštanja ovih putanja, odnosno periodi kada je obrazovanje viđeno kao podrška karijernom razvoju, ali i određeni periodi koji su od strane ispitanika prepoznati kao jaz između obrazovanja i karijere. Periodi preklapanja obrazovanja i karijernog razvoja (gde je obrazovanje viđeno kao podrška karijernom razvoju), kao i periodi jaza između obrazovanja i karijernog razvoja, mogu se sagledati kao nosioci različitih podataka o kvalitetu obrazovanja. Analizom jaza između obrazovanja i karijere, uočava se mogućnost da taj jaz bude umanjen različitim obrazovnim intervencijama. Polemika o tome zašto ta mogućnost nije ostvarena, otvara nova značajna pitanja kvaliteta obrazovanja u Srbiji.This paper consider the quality of education viewed as a support for the career development of adults. The basis for the review of the quality of education lies in the results of research conducted to examine the „trajectory“ of education and learning and the „trajectory“ of career, trough the application of „lifeline“ method. Through analysis of the trajectory of education and career paths, it is noticed that there are certain points of intersection of these trajectories, ie periods when education is seen as a support career development, but also some periods which were identified by respondents as the gap between education and careers. Periods of „overlapping“ of education and career development (where education is seen as a support for career development), as well as the period of gap between education and career development, can be seen as bearers of various data about the quality of education. The analysis of the gap between education and career shows that there is an opportunity for this gap to be reduced using different educational interventions. Polemic about why this option has not been realized, opens up new important issues of quality of education in Serbia

Kompetencije u obrazovanju – iz brazilske i srpske perspektive

The goal of this paper is to compare the understanding of the concept of competences in Brazil and Serbia, together with reflecting on the different contexts under which these countries are developing. Theoretical framework provides reflection on the term, concept and approaches related to competences. Comparison is done through the analysis of the relevant scientific papers in both countries, together with the analysis of the educational policies and practice. The main findings reflect on changes in the meaning of the term competence over time, increase in the number of scientific papers that happened in both countries, special interest of authors regarding competences, approaches in defining competences and detecting influences on the concept of competences in Serbia and Brazil.Cilj ovog rada je da se uporedi razumevanje pojma kompetencija u Brazilu i Srbiji, kao i da se osvrne na različite kontekste razvoja tih dveju zemalja. Teoretski okvir će pružiti osvrt na prirodu termina ‘kompetencije’, na sam pojam i razne pristupe kompetencijama. Komparacija se vrši uporednom analizom relevantnih naučnih radova iz dveju zemalja, zajedno sa analizom obrazovnih politika i praksi. U glavnim nalazima se osvrćemo na promenu značenja termina ‘kompetencije’ u proteklom periodu, na porast broja naučnih radova u obe zemlje, na naročito interesovanje autora za pojam kompetencija, te pristupe definisanju kompetencija i uticajima na taj pojam u Srbiji i Brazilu

Synthesis of New Pd(II) Complexes Bearing Organoselenium Ligands and Evaluation of Cytotoxic, Antimicrobial, Antioxidant Activity and DNA-binding studies

The potential utility of organoselenium compounds in pharmacy and medicine has been subject of many studies performed during past years. In addition to their important application in synthetic purposes, organoselenium compounds have also demonstrated ability to act as antioxidant, anti-inflammatory, neuroprotection, chemotherapeutic and chemopreventive agents.1, 2 Coordination of organoselenium compounds to transition metals provides very interesting pharmacological properties which arouses an interest for further research in that area.3 In this study, we have examined biological activity of 3 newly synthesized Pd(II) complexes bearing organoselenium ligands (Figure 1) through the antimicrobial, antibiofilm, antioxidant activity parallel with DNA and BSA-binding ability. The antibacterial activity of Pd(II) complexes was tested against 18 strains of bacteria determining the minimal inhibitory concentration (MIC) and the minimal bactericidal concentration (MBC) using microdilution method. The influence on bacterial biofilm formation was determined by tissue culture plate method. Antioxidant activity was evaluated as DPPH radicals scavenging activity expressed as the ЕС50 values. Overall, the investigated complexes exhibited good to moderate activity. Furthermore, the interaction of metal complexes to calf thymus DNA (CT-DNA) and bovine serum albumin (BSA) was examined. Overall, the studied complexes exhibited good DNA and BSA interaction ability. All obtained results in this study indicate that the introduction of these types of ligands can be used to improve the reactivity of Pd(II) complexes. In addition the potential cytotoxicity of investigated complexes was tested by MTT assay on HCT-116 cell line. Together, these observations show the reactivity characteristics needed for a potential anti-tumor agent. Prominent results obtained in the evaluation of cytotoxic activity of these 3 complexes gave a rise for the further research on their anti-tumor activities.Publishe

Citotoksični i apoptotički učinci 17α-etinilestradiola i dietilstilbestrola na CHO-K1 stanice

There is considerable concern about the substances present in the environment and their potential to interfere with the endocrine system of vertebrates. Among these, the so-called endocrine-disrupting compounds, which can modulate or disrupt developmental and reproductive processes, substances with estrogenic activity have attracted most attention. Concerns about the presence of these compounds in the environment have led to the development of screening and testing assays that are able to detect such substances and evaluate their potential to induce adverse effects. In vitro systems such as mammalian and fish cell lines have become of growing importance in toxicity testing of such compounds. The cytotoxic and apoptotic effects induced by 17α-ethynylestradiol and diethylstilbestrol were studied on CHO-K1 cell line. Trypan blue exclusion method was used to determine the cell viability. Cytotoxicity of 17α-ethynylestradiol (0.34–34 μM) and diethylstilbestrol (0.37–37 μM) was found to be concentration-dependent with IC50 values of 12.8 and 10.4 μM after 72 h of exposure, respectively. In treated CHO-K1 culture cell death was assessed by determining morphological changes by haematoxilyn and eosin staining, nuclear morphology by fluorescein diacetate/propidium iodide staining and fluorescence microscopy, DNA fragmentation by TUNEL method and translocation of phosphatidyl serine by flow cytometry. The obtained results showed that 17α-ethynylestradiol induced apoptosis, while diethylstilbestrol induced necrosis in the treated CHO-K1 cells.Javnost sve više zabrinjavaju brojne tvari u okolišu koje mogu utjecati na endokrini sustav kralježnjaka. Među tzv. endokrinim modulatorima, koji mogu poremetiti ili potpuno narušiti razvojne i reproduktivne procese u organizmu, najveću pozornost privlače tvari što imaju estrogenu aktivnost. Ta je zabrinutost potaknula razvoj novih metoda za njihovo praćenje i određivanje te izbjegavanje neželjenih učinaka. Testovi in vitro sa staničnim linijama sisavaca i riba postali su važni modelni sustavi u ispitivanju toksičnosti tih spojeva. Citotoksični i apoptotički učinci 17α-etinilestradiola i dietilstilbestrola ispitani su na CHO-K1 staničnoj liniji. Za određivanje preživljavanja stanica upotrebljena je metoda tripan plavo. Citotoksičnost 17α-etinilestradiola (0,34-34 µM) i dietilstilbestrola (0,37-37 µM) ovisi o koncentraciji, a izračunate IC50 vrijednosti nakon 72 sata nakon tretmana iznosile su pojedinačno 12,8 i 10,4 µM. Smrt CHO-K1 stanica praćena je na temelju uočenih morfoloških promjena, bojenjem hematoksilinom i eozinom, zatim promjena u izgledu jezgre, bojenjem fluorescein diacetatom/propidijevim jodidom i fluorescentnom mikroskopijom, te prema fragmentaciji DNA TUNEL metodom i translokaciji fosfatidilserina protočnom citometrijom. Dobiveni rezultati upućuju na to da 17α-etinilestradiol uzrokuje apoptozu u CHO-K1 stanicama, a dietilstilbestrol njihovo odumiranje procesom nekroze

Synthesis, characterization, antitumor potential, and investigation of mechanism of action of copper(ii) complexes with acylpyruvates as ligands: interactions with biomolecules and kinetic study

Considering the urgency of finding a cure for vicious diseases such as tumors, we have synthesized and characterized a small series of new copper(ii) complexes with biologically important ligands such as acylpyruvate. In addition to this, we used another four copper(ii) complexes, with ligands of the same type to examine the antitumor potential. The antitumor potential of the copper(ii) complexes was examined on three tumor cell lines and one normal human cell line using the MTT assay. All seven tested complexes showed very good cytotoxic effects. Two copper complexes that showed the best antitumor potential were selected for further testing that showed the best potential for potential application in the future. The mechanism of activity of these complexes was examined in detail using tests such as cell cycle, ROS level, oxidative DNA damage, and proteins related to hypoxia analysis. In addition, we examined the binding abilities of these complexes with biomolecules (Guo, Ino, 5′-GMP, BSA, and DNA). The results showed that the tested compounds bind strongly to DNA molecules through intercalation. Also, it has been shown that the tested compounds adequately bind to the BSA molecule, which indicates an even greater potential for some future application of these compounds in clinical practice. © 2022 The Royal Society of Chemistry

Advances in formal Slavic linguistics 2016

Advances in Formal Slavic Linguistics 2016 initiates a new series of collective volumes on formal Slavic linguistics. It presents a selection of high quality papers authored by young and senior linguists from around the world and contains both empirically oriented work, underpinned by up-to-date experimental methods, as well as more theoretically grounded contributions. The volume covers all major linguistic areas, including morphosyntax, semantics, pragmatics, phonology, and their mutual interfaces. The particular topics discussed include argument structure, word order, case, agreement, tense, aspect, clausal left periphery, or segmental phonology. The topical breadth and analytical depth of the contributions reflect the vitality of the field of formal Slavic linguistics and prove its relevance to the global linguistic endeavour. Early versions of the papers included in this volume were presented at the conference on Formal Description of Slavic Languages 12 or at the satellite Workshop on Formal and Experimental Semantics and Pragmatics, which were held on December 7-10, 2016 in Berlin

Advances in formal Slavic linguistics 2016

Advances in Formal Slavic Linguistics 2016 initiates a new series of collective volumes on formal Slavic linguistics. It presents a selection of high quality papers authored by young and senior linguists from around the world and contains both empirically oriented work, underpinned by up-to-date experimental methods, as well as more theoretically grounded contributions. The volume covers all major linguistic areas, including morphosyntax, semantics, pragmatics, phonology, and their mutual interfaces. The particular topics discussed include argument structure, word order, case, agreement, tense, aspect, clausal left periphery, or segmental phonology. The topical breadth and analytical depth of the contributions reflect the vitality of the field of formal Slavic linguistics and prove its relevance to the global linguistic endeavour. Early versions of the papers included in this volume were presented at the conference on Formal Description of Slavic Languages 12 or at the satellite Workshop on Formal and Experimental Semantics and Pragmatics, which were held on December 7-10, 2016 in Berlin

Advances in formal Slavic linguistics 2016

Advances in Formal Slavic Linguistics 2016 initiates a new series of collective volumes on formal Slavic linguistics. It presents a selection of high quality papers authored by young and senior linguists from around the world and contains both empirically oriented work, underpinned by up-to-date experimental methods, as well as more theoretically grounded contributions. The volume covers all major linguistic areas, including morphosyntax, semantics, pragmatics, phonology, and their mutual interfaces. The particular topics discussed include argument structure, word order, case, agreement, tense, aspect, clausal left periphery, or segmental phonology. The topical breadth and analytical depth of the contributions reflect the vitality of the field of formal Slavic linguistics and prove its relevance to the global linguistic endeavour. Early versions of the papers included in this volume were presented at the conference on Formal Description of Slavic Languages 12 or at the satellite Workshop on Formal and Experimental Semantics and Pragmatics, which were held on December 7-10, 2016 in Berlin