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Professional competencies of educators to work in residential care
No full textRad se bavi profesionalnim kompetencijama odgajatelja zaposlenih u dječjim domovima u kojima se odgajaju djeca i mladi bez roditelja ili bez odgovarajuće roditeljske skrbi. Odgajatelji zaposleni u dječjem domu mogu biti osobe različitog formalnog obrazovanja kako odgajateljski studij za rad u istom ne postoji. Kompetencije odgajatelja stavljene su u kontekst suvremenih promjena i proces deinstitucionalizacije što zahtijeva da se skrb temelji na znanstveno utemeljenim činjenicama i programima koji doprinose pozitivnim ishodima za korisnike. Svrha rada je proširiti spoznaje o kompetencijama odgajatelja u dječjim domovima. Rad je podijeljen na dva dijela. U prvom, teorijskom dijelu rada dati je prikaz dječjeg doma, brojne kritike domova, različiti modeli domske skrbi kao i prikaz istraživanja o korisnicima te njihova perspektiva. Nadalje se razmatra pojam odgoja, njegovi aspekti, zadaci i ciljevi koji moraju biti usmjereni pozitivnom razvoju korisnika. Odgajatelj kao nositelj neposrednog odgojnog rada u domu ima brojne zadatke koje mora staviti u funkciju svog odgojnog, pedagoškog rada s korisnicima. Povezano s time nužne su mu brojne kompetencije za uspješan rad. U radu se razmatra pojam kompetencija i različiti pristupi kompetencijama, kao i zahtjevi za kvalifikacijama i potrebnim znanjima odgajatelja u skladu sa suvremenim spoznajama i prisutnim procesom deinstitucionalizacije. Drugi dio rada prikaz je empirijskog istraživanja provedenog na uzorku 137 odgajatelja metodom procjene i samoprocjene. Cilj je bio utvrditi što čini kompetentnog odgajatelja te utvrditi znanja, sposobnosti i stavove odgajatelja o vlastitoj kompetentnosti/nekompetentnosti za rad s djecom u domu. Istraživane su pedagoške kompetencije odgajatelja koje čine srž profesionalnih kompetencija odgajatelja. Odgajatelji su procjenjivali i povoljnost radnog okruženja te poteškoće s kojima se susreću u radu ne bi li se dobili dodatni uvidi u njihove kompetencije. S obzirom na izvršene procjene i samoprocjene odgajatelja, testirano je ukupno 10 hipoteza obzirom na nezavisne varijable i tri glavne hipoteze rada. Zaključeno je da su pedagoške kompetencije nužne odgajateljima za uspješan rad u dječjem domu, odgajatelji se ne smatraju u potpunosti pedagoški kompetentni te postoji statistički značajna razlika između procjene nužnih kompetencija i samoprocjene vlastitih kompetencija odgajatelja.The paper deals with the professional competences of educators employed in children's homes where children and young people without parents or without adequate parental care are raised. Educators employed in a children's home can be professionals of different formal education such as educational and rehabilitation sciences, social work, psychology, pedagogy and speech therapy, as the educational study for work in the children's home does not exist. The issue of competences of educators in the Republic of Croatia has not been thoroughly investigated until now. Educators' competences are placed in the context of modern changes and the process of deinstitutionalization, which requires effort to be based on scientific facts and programs that contribute to positive outcomes for users. The purpose of the paper is to expand the knowledge about the competences of educators in children's homes based on the review of theoretical knowledge and the results of empirical research. The work is divided into two parts. The first, theoretical part of the paper, is to give an overview of children's home, a great deal of criticism of homes presented by the authors in recent years. Children and young people who come into the system are burdened with numerous problems, both emotional and behavioral, with numerous traumatic experiences. Various models present in the world, good home practices and presentation of user surveys, as well as their perspective are described. Further consideration is given to the concept of upbringing, its aspects, tasks and goals that must be directed towards the positive development of the user. The educator, as the holder of direct educational work in the home, has numerous tasks that must be put into function of their educational work. Related to this, they need to possess many competences for successful work. The concept of competences and different approaches to competences are considered, as well as the requirements for qualifications and necessary knowledge of educators in accordance with modern knowledge and the present process of deinstitutionalization. From the theoretical part of the work it is clear that educators need knowledge in the field of trauma. It is necessary to raise awareness about the impact of trauma on users, understanding, recognizing and responding to the effects of trauma, creating physical, psychological and emotional safety of users, and empowering and helping users to restore a sense of control and take an active role in the recovery process and all due to the traumatic history of the users. Educators need knowledge and understanding of the theory of attachment, difficulties that can arise if users are insecurely affected, and ways in which they can favorably influence the development of safe attachment. The second part of the paper is a review of empirical research conducted on a sample of 137 educators employed in children's homes in the Republic of Croatia by the method of assessment and self-assessment. This is convenience sample. Data were collected via instrument which was designed for the purpose of this research based on adapted version of the questionnaire Pedagogical-competence profile of secondary school religious teachers (Ninčević, 2012) and Self-reported Competency Scale (Hartje et al., 2007) based on the features of the concept of positive development of children and youth (Eccles and Gootman, 2002) The aim was to determine what makes a competent educator and to determine the knowledge, abillities and attitudes of educators toward their own competence / incompetence to work with children in the home. The issue of educators' competence starts from a holistic approach to assessment and the theory of positive development of children and youth, given that programs that integrate theoretical propositions on a practical level have resulted in positive outcomes for children and youth. Pedagogical competences that will contribute to the positive growth and development of users were investigated. Educators also assessed the suitability of the work environment and the difficulties they encounter in their work. Differences between educators were tested with regard to the type and level of formal education, length of service, form of care in which they work, attendance at supervision and professional development. With regard to the performed assessments and self-assessments of educators, a total of three main hypotheses were tested. At the end of the paper comments of educators were analyzed. The first research task was to investigate through an assessment of educators which of the listed pedagogical competencies the educators consider important for the successful work of educators in the home. The results of the research indicate that educators consider that pedagogical competencies are extremely important for successful work. By assessing the importance of pedagogical competences, three factors were obtained through factor analysis: Pedagogical competences for individual approach, Knowledge of the law and the rights of the child, and Pedagogical competences for group work. There is no difference between educators with regard to independent variables, they agree in their assessments. As can be seen from the results, the educators also agree that they need skills and abilities that will enable users to develop positively. Factor analysis resulted in five factors: Structuring of individual work activities, Structuring of group work activities, Ensuring safety, Expectations in accordance with the individual and Cooperation. The Cooperation factor was the only factor that the educators did not perceive in the same way and did not give it the same importance as the rest. Nevertheless, the first main hypothesis (Hg1) was confirmed. Educators believe that pedagogical competences are extremely important for the successful work of educators in a children's home. They are relate to group and individual work, and are important pedagogical skills and abilities that enable the creation of an environment aimed at the positive youth development. The second research task was to investigate one's own experience of pedagogical competences through self-assessment, so, educators assessed their own pedagogical competences and pedagogical success. Educators feel mostly pedagogically successful. They feel satisfaction and security when they work with children, they manage to create and maintain a positive atmosphere in their work, they use various methods, they plan their work regularly and they communicate with children and colleagues successfully. The least competent feeling is working with children who have developmental difficulties. Educators assessed their pedagogical success through 5 factors: Successful group and team work, Professional development, Insufficient pedagogical competences for working with different groups, Insufficient formal education and Satisfaction and commitment to pedagogical work. Educators perceive the professional work environment as favorable. The favorable working environment can be seen in security, well-defined work tasks, decision-making opportunities, appropriate encouragement and professional development opportunities. The biggest difficulties for educators are communication with parents, involvement of all users in activities, and achieving educational goals. Educators assess their own development of pedagogical competences as good or very good. They perceive themselves as competent, but the second main hypothesis can be only partially accepted. By putting pedagogical knowledge, skills and abilities in the function of direct work with users, the results show that educators have the abilities related to the implementation of appropriate activities and that they support users and have expectations that users can fulfill, that is, they respect individual differences, needs and interests of a user. However, their abilities, according to assessments, are insufficient to ensure the complete safety of the users in the children's home and to achieve an appropriate work structure in the children's home. Deficiencies were noticed in the field of working with children with developmental disabilities and competences for cooperation, especially with the parents of beneficiaries. Although educators' self-assessments tend to have higher values, if we look at them in relation to assessments of necessary competences, which are almost always higher, in that case, we cannot consider educators to be pedagogically competent enough so the second hypothesis (Hg2) can be partially accepted. The third research task was to investigate the existence of differences between the assessment of generally desirable pedagogical competences and actually existing pedagogical competences based on the assessments and self-assessments of educators. Self-assessment of competences is observed in relation to the assessment of the required competences. The arithmetic means of self-assessment of the development of competences in relation to the assessment of their importance for performance are different. The estimates of required competences have higher arithmetic means while self-assessments of the development of those competencies have lower arithmetic means. The difference is statistically significant. So, the third hypothesis (Hg3) must therefore be rejected. There is a statistically significant difference in terms of the assessment of the necessary pedagogical competences and the actually self-assessed pedagogical competences of the educators. The length of service variable makes a statistically significant difference, whereby educators with the shortest length of service are judged to be less competent than those with the longest length of service in terms of Knowledge of the law and children's rights and Intercultural (in)competence. A statistically significant difference was confirmed for the factor Expectations in accordance with the individual, whereby educators who did not attend supervision and those who did not have a single day of professional development are judged to be significantly more competent and are considered significantly more important. Educators with secondary school education are considered less competent compared to educators with higher education. The conducted research provides initial insights into the investigated issue and opens up possibilities for further research. Further research can be carried out by using the assessment method and by involving other professional workers and the director of the home in assessing the competences of educators. In addition, it would also be interesting to check how the educators' competencies are related to the structuring of the children's home program and the psychosocial climate in the home, that is, checking specific competencies that are predictors of a positive psychosocial climate. In conclusion, the results of this research show that a professionally competent educator is made up of pedagogical competencies that are manifested in the organization and implementation of group and individual work with users, knowledge of laws and children's rights, and pedagogical skills and abilities that enable the creation of an environment that will contribute to the positive development of children and young people. For the positive development of children and young people, it is necessary that educators have the ability to plan, organize and carry out appropriate activities with users aimed at strengthening their individual capacities, expectations that are in line with the individual, to encourage interculturality, ensure the safety of users and successfully structure group activities. Given the observed lack of competence, educators need to be provided with continuous professional training related to working with children and youth with developmental disabilities, pedagogical work with parents, structuring group activities and ensuring safety
Potential therapeutic biomolecules of probiotics as living drugs
No full textCilj ovog rada bio je istražiti pet odabranih sojeva bakterija mliječne kiseline (BMK), izoliranih iz majčinog mlijeka, selekcioniranih producenata potencijalnih terapijskih biomolekula – S-proteina i egzopolisaharida (EPS-a). Proteomička analiza sojeva Levilactobacillus brevis MB1, MB2, MB13 i MB20 je potvrdila prisutnost površinskih S-proteina, čija je tercijarna struktura određena primjenom I-TASSER servera. Dokazana je funkcionalna uloga S-proteina u preživljavanju simuliranih uvjeta gastrointestinalnog trakta, adheziji na Caco-2 stanice te kompetitivnoj ekskluziji patogena. U genomu soja Limosilactobacillus fermentum MC1 su detektirani geni uključeni u Wzx/Wzy-ovisan put biosinteze EPS-a, a strukturna analiza EPS-a provedena NMR (engl. nuclear magnetic resonance) spektroskopijom je pokazala da se sastoji od dva polisaharida. Dokazana je uloga EPS-a u adheziji na Caco-2 stanice te kompetitivnoj ekskluziji Escherichia coli 3014. Ustanovljeno je antimikrobno djelovanje supernatanata ispitivanih sojeva BMK prema patogenim bakterijama te antioksidacijsko djelovanje ispitivanih sojeva. Povećanje ekspresije JAM-A, okludina, ZO-1, MUC2 i ZG16 te smanjenje ekspresije proupalnih citokina IL-6, IL-8 i IL-1β in vitro ukazuju na regeneracijsko i imunomodulacijsko djelovanje sojeva BMK i njihovih biomolekula. Pozitivan učinak soja L. fermentum MC1 i njegovog EPS-a na upalne procese u crijevima miševa, regeneraciju crijevne sluznice i mikrobiotu, ukazuje na potencijalnu primjenu soja kao probiotika i njegovih EPS-a kao prebiotika. Sojevi BMK su zaštićeni mikroinkapsulacijom u alginatu, sa i bez dodatka galakto- ili frukto-oligosaharida, te nanoinkapsulacijom, što se očituje velikom stopom preživljavanja nepovoljnih uvjeta (> 10⁸ CFU/mL).The aim of this study was to investigate five lactic acid bacteria (LAB) strains, isolated from breast milk, selected as producers of potential therapeutic biomolecules – S-proteins and exopolysaccharides (EPSs). Proteomic analysis of strains Levilactobacillus brevis MB1, MB2, MB13 and MB20 confirmed the presence of surface S-proteins, whose tertiary structure was determined using the I-TASSER server. The functional role of S-proteins was demonstrated in terms of survival under simulated gastrointestinal tract conditions, adhesion to Caco-2 cells and competitive exclusion of pathogens. Genes involved in the Wzx/Wzy-dependent pathway of EPSs biosynthesis were detected in the genome of Limosilactobacillus fermentum MC1, and nuclear magnetic resonance (NMR) structural analysis revealed that EPSs consist of two polysaccharides. The role of EPSs in adhesion to Caco-2 cells and competitive exclusion of Escherichia coli 3014 was demonstrated. The antimicrobial activity of the supernatants of the tested LAB strains against pathogenic bacteria and the antioxidant activity of the tested strains were confirmed. The increase in the expression of JAM-A, occludin, ZO-1, MUC2 and ZG16, and the decrease in the expression of the proinflammatory cytokines IL-6, IL-8 and IL-1β indicate the regenerative and immunomodulatory effects of the LAB strains and their biomolecules. Positive effects of L. fermentum MC1 and its EPSs on inflammatory processes in the intestine of mice, the regeneration of the intestinal mucosa and the microbiota indicate potential application of the strain L. fermentum MC1 as probiotic and its EPSs as prebiotics. The LAB strains were protected by microencapsulation in alginate, with and without the addition of galacto- or fructo-oligosaccharides, and by nanoencapsulation, as evidenced by a high survival rate under unfavourable conditions (> 10⁸ CFU/mL)
MODIFICATION OF POLYESTER FABRIC TO IMPROVE THE BINDING OF THE BIOPOLYMER CHITOSAN AND REDUCE THE PARTICLE CONTENT IN WASTEWATER FROM THE WASHING PROCESS
No full textGlobalni problem opterećenja okoliša čestičnim tvarima iz različitih izvora nametnuo je potrebu istraživanja njihova podrijetla, karakterizacije te prevencije generiranja. U skladu s navedenim u ovom istraživanju, koje je provedeno u četiri faze, praćen je utjecaj konvencionalnih i naprednih procesa predobrade poliesterske tkanine s ciljem poboljšanoga vezanja biopolimera kitozana i smanjenja sadržaja čestične tvari u efluentima od procesa pranja. Konvencionalni postupci alkalne hidrolize provedeni su uz dodatak promotora, a napredni procesi predobrade primjenom tehnologije niskotlačne hladne plazme i ozoniranja. Utjecaj konvencionalnih i naprednih procesa predobrade poliesterske tkanine na postizanje poboljšanoga vezanja biopolimera kitozana i smanjenja sadržaja čestične tvari u otpadnoj vodi nadziran je u prve tri faze istraživanja u kojima su promatrani fenomeni praćeni analizom: i) svojstava i stabilnosti dobivenih polimernih struktura poliester/kitozan; ii) svojstava i stabilnosti dobivenih polimernih struktura poliester/kitozan nakon procesa pranja; iii) efluenata od procesa pranja s naglaskom na sadržaj čestične tvari; iv) filtarskog kolača dobivenog membranskom filtracijom efluenata od procesa pranja. U četvrtoj fazi istraživanja svi dobiveni rezultati obuhvaćeni su u provedbi hijerarhijske klaster analize kako bi se definirale sveobuhvatne sličnosti i razlike među promatranim uzorcima prije i nakon predobrada, modifikacije kitozanom i procesa pranja. Primjenom normiranih i instrumentalnih metoda analize svojstava tekstilnog materijala istražen je utjecaj procesa pranja na postignuta funkcionalna svojstva. Karakterizacija neobrađene i predobrađene poliesterske tkanine te formirane strukture poliester/kitozan provedena je određivanjem debljine i vlačnih svojstava. Nadalje su korištene metode određivanja vrijednosti pH vodenog ekstrakta, apsorbirane vode, potencijal strujanja, identifikacije kitozana, infracrvena spektroskopija s Fourierovom transformacijom (FTIR). Određivane su i morfološka obilježja tkanine i dobivene strukture, sadržaj karboksilnih skupina te antimikrobna aktivnost. Nakon izlaganja polimerne strukture čimbenicima u procesu pranja sa standardnim deterdžentom istražen je njihov utjecaj na postignuta funkcionalna svojstva te na potencijal otpuštanja čestica koji je praćen karakterizacijom efluenata fizikalno-kemijskim metodama s naglaskom na određivanje čestične tvari. Za karakterizaciju efluenata od procesa pranja predobrađene poliesterske tkanine te formirane strukture poliester/kitozan upotrijebljene su metode određivanja ukupne suspendirane, ukupne otopljene i ukupne čvrste tvari, vrijednosti pH i elektrovodljivosti, mutnoće, određivanja kemijske potrošnje kisika te biokemijske potrošnje kisika, analiza veličina i raspodjele čestica te zeta potencijal i elektroforetska mobilnost čestica. Karakterizacija filtarskog kolača provedena je mikroskopijom uparenom s FTIR spektroskopijom. Rezultatima istraživanja potvrđeno je da predobrađena i aktivirana površina poliesterske tkanine pokazuje veći afinitet za modifikacije svojstava biopolimerom kitozanom čime je dobivena struktura poliester/kitozan. Dobivene strukture poliester/kitozan zadržale su stabilnost nakon provedenih ciklusa pranja. Povoljno zaštitno djelovanje kitozana u dobivenim strukturama potvrđeno je u svim ciklusima pranja, a posebice u početnim ciklusima koji se smatraju ključnima za znatan potencijal otpuštanja čestične tvari. Provedena hijerarhijska klaster analiza, na svim dobivenim rezultatima, pokazala se svrsishodnom metodom za definiranje sličnosti i razlika među dobivenim poliester/kitozan strukturama prije i nakon procesa pranja.The global problem of environmental pollution by particulate matter from various sources has led to the need to investigate the origin, characterisation and prevention of the formation of particulate matter. In accordance with the statements of this study, which was carried out in four phases, the effects of conventional and advanced pretreatment processes of polyester fabrics were monitored with the aim of improving the binding of the biopolymer chitosan and reducing the particles in the effluents from the washing process. Conventional alkaline hydrolysis processes with the addition of promoters and advanced pretreatment processes using low pressure cold plasma and ozonation technology were carried out. The effects of the conventional and advanced pretreatment processes of polyester fabrics on achieving improved binding of the biopolymer chitosan and reducing particles in the wastewater were monitored in the first three research phases, in which the observed phenomena were analysed by: (i) properties and stability of the polyester/chitosan polymer structures; (ii) properties and stability of the obtained polyester/chitosan polymer structures after washing; (iii) effluents from washing, focusing on the content of particulate matter; (iv) filter cake obtained by membrane filtration of the washing effluents. In the fourth phase of the study, all the results obtained were included in the implementation of a hierarchical cluster analysis in order to define similarities and differences between the samples observed before and after pretreatment, modification with chitosan and washing. The influence of the washing process on the obtained functional properties was investigated by applying standardised and instrumental methods to analyse the properties of textile material. The characterisation of the untreated and pretreated polyester fabric and the polyester/chitosan structure formed was carried out by determining the thickness and tensile properties. In addition, the methods for determining the pH value of the aqueous extract, the absorbed water, the streaming potential, chitosan identification and Fourier transform infrared spectroscopy (FTIR) were used. The morphological properties of the fabric and the structures obtained, the content of carboxyl groups and the antimicrobial activity were also determined. The resulting polymer structure was subjected to a washing process with a standard detergent at 60°C for 10 cycles to investigate the influence of the washing process on the obtained functional properties. The effluents were collected after each washing cycle and combined into a composite sample, from the first to the fifth cycle, from the sixth to the tenth cycle and in total from the first to the tenth cycle. The wastewater from the washing process was analysed by determining the particle content with the task of identifying released fibre fragments and the influence of the processing procedures on the release potential. Methods for determining total suspended solids, total dissolved solids, total solids, pH and electrical conductivity, turbidity, determination of chemical oxygen demand and biochemical oxygen demand, analysis of particle size and distribution, zeta potential and electrophoretic mobility of the particles were used for characterization of effluents from the washing of the pretreated polyester fabric and the polyester/chitosan structure formed. In addition to the analysis of the wastewater, an analysis of the filter cake obtained by membrane filtration of the wastewater was carried out to detect the released fibrils.The characterisation of the filter cake was carried out by microscopy in conjunction with FTIR spectroscopy. The results of the investigation confirmed that the pretreated and activated surface of the polyester fabric has a greater affinity for the modification of properties by the biopolymer chitosan, resulting in a polyester/chitosan structure. The polyester/chitosan structures obtained retained their stability even after washing cycles. The favourable protective effect of chitosan in the obtained structures was confirmed in all washing cycles, especially in the first cycles, which are considered crucial for the significant potential of particle release. The advanced pretreatment of polyester fabrics with low-pressure cold plasma technology and ozonation can be used as a technologically acceptable and more environmentally friendly substitute for conventional processes. Pretreatment processes and the number of washing cycles influence the content of particulate matter originally belonging to the biopolymer or polymer component of the polyester/chitosan structure. The characterisation of wash effluents by adjusting the TSS/TDS ratio and determining the characteristic particle diameters from the size distribution function enables the detection of the size categorisation of potentially released particles in the washing process. Particle size distribution is a useful method for the characterisation of effluents from the washing of polyester/chitosan structures as it enables the establishment of relationships with other parameters used for the characterisation of effluents. The distribution of size particles in effluents from the washing of polyester/chitosan structures depends on the structure of the polymer, the interaction of chitosan with the structure, the stability of the modification through successive washing cycles, the content and size of suspended particles and the effect of factors in the washing process. Colloids and particles, which are responsible for the degree of turbidity, usually have a negative surface charge, which is expressed by the zeta potential of the particles in the solution. Together with the electrophoretic mobility of the particles, they represent a valuable parameter in the characterisation of effluent particles. The application of micro-FTIR spectroscopy in analysing the filter cake obtained by membrane filtration of the effluent proved to be an effective method for detecting released particles and/or microfibrils. Hierarchical cluster analysis as an advanced statistical technique has proven its usefulness in analysing similarities and differences between polyester/chitosan structures prepared by different pretreatments and washing cycles
Novel 2-substituted benzothiazole and benzimidazole derivatives – synthesis, structural characterization and antitumoral and antibacterial evaluations
No full textU ovom doktorskom radu opisana je sinteza, strukturna karakterizacija i biološka aktivnost novih derivata 2-arilbenzimidazola i 2-arilbenzotiazola, hidrazonskih derivata benzotiazola te 1,2,3-triazolnih derivata kumarina i iminokumarina. U sintezama su pored konvencionalnih metoda korištene i ekološki prihvatljive zelene metode poput sinteza potpomognutih mikrovalovima i ultrazvukom te mehanokemijske reakcije. Ultrazvukom potpomognutom reakcijom ciklokondenzacije pripravljenih O-alkiliranih benzaldehida (1‒6) ili 1,2,3-triazolnih derivata benzaldehida (10 i 11) s različito supstituiranim 1,2-diaminobenzenima uz Na2S2O5 kao oksidacijsko sredstvo, pripravljeni su novi O-alkilirani (12‒27) i 1,2,3-triazolni derivati 2-arilbenzimidazola (28‒33). Derivati 2-(4-alkoksifenil)benzotiazola (47–55) sintetizirani su konvencionalnim načinom reakcijom O-alkiliranja priređenih 2-(4-hidroksifenil)benzotiazola (40–46) s odgovarajućim aminoalkil-halogenidima uz K2CO3, dok su derivati
2-(4-alkoksifenil)-6-halobenzotiazola (56–67) pripravljeni mikrovalovima potpomognutom reakcijom O-alkiliranja 2-(4-hidroksifenil)benzotiazola (43–46). Bakrom kataliziranom Huisgenovom 1,3-dipolarnom cikloadicijom morfolinskog azida (9) i sintetiziranih derivata 2-(4-O-(propargilfenil)benzotiazola (68–74) pripravljeni su 1,2,3-triazolni derivati benzotiazola (75–81). U svrhu odabira metode sinteze derivata 2- i 3-O-(1-aril-1,2,3-triazolil)fenilbenzotiazola (88‒117) provedeno je optimiranje reakcijskih uvjeta na modelnoj klik reakciji s azidobenzenom uključujući konvencionalnu, mehanokemijsku i sintezu potpomognutu ultrazvukom. Mehanokemijskom klik reakcijom uz pomoć kapljevine su postignuta najveća iskorištenja benzotiazolnih derivata (88, 98 i 108) uz najkraće vrijeme trajanja reakcije te je mehanokemija odabrana kao metoda za pripravu 2- i 3-O-(1-aril-1,2,3-triazolil)fenilbenzotiazola (88‒117) te derivata 2-(4-O-(1-aril-1,2,3-triazolil)fenil)benzotiazola (118‒156). Hibridi benzotiazola i 4-alkilaminobenzena povezani hidrazonskom spojnicom (169–202) pripravljeni su kao E-izomeri mehanokemijskom sintezom bez otapala reakcijom kondenzacije sintetiziranih 4-alkoksibenzaldehida (1, 2, 4, 5, 161‒168) i 2-hidrazinilbenzotiazola (158–160). Mikrovalovima potpomognutom klik reakcijom kataliziranom bakrom iz odgovarajućih azida i terminalnih alkina sintetizirani su 1,2,3-triazolni iminokumarinski (207–212) i kumarinski derivati (213–223). Pripravljenim derivatima strukture su potvrđene spektroskopijom 1H- i 13C-NMR kao i dvodimenzijskim metodama NOESY, HSQC i HMBC. Antiproliferativna aktivnost in vitro pripravljenim spojevima ispitana je na nizu humanih tumorskih staničnih linija te na zdravim stanicama. Antibakterijska aktivnost in vitro je ispitana na Gram-pozitivnim i Gram-negativnim bakterijskim sojevima uključujući klinički rezistentne sojeve MRSA i VRE. Derivatima benzotiazola s 1,4-disupstituiranim
1,2,3-triazolnim prstenom (88‒97, 108‒117 i 118–156) ispitana je i antivirusna aktivnost. Kako bi se utvrdila moguća korelacija između antiproliferativne i antioksidativne aktivnosti, derivatima koji su pokazali izraženu antiproliferativnu aktivnost ispitana je antioksidativna aktivnost in vitro metodom DPPH. Od svih ispitanih spojeva najizraženiju antiproliferativnu aktivnost in vitro su pokazali: 2-(4-(2-N,N-dietiletoksi)-3-fluorfenil)-6-klorbenzimidazol (23) (K-562, Z-138, IC50 = 2.0 μM), 2-(4-(N,N-dietiletoksi)-3-metoksifenil)-6-klorbenzotiazol (59) (CFPAC, IC50 = 1.03 μM) i (E)-2-(3-(4-(N,N-dimetiletoksi)-3-fluorfenil)hidrazonil)-6-klorbenzotiazol (188) (CAPAN, IC50 = 0.6 μM, NCI-H460, IC50 = 0.9 μM). Najsnažniju selektivnu antibakterijsku aktivnost su pokazali derivati 2-(4-alkoksifenil)-6-klorbenzimidazola (15‒17) prema Enterococcus faecalis (MIC = 0.25‒1 mg/mL) te 2-(4-(N,N-dietiletoksi)fenil)-6-klorbenzotiazol (50) koji je pokazao najizraženiju aktivnost prema soju MRSA 13276
(MIC = 2 μg/mL). Najizraženiju antivirusnu aktivnost pokazao je triazolni derivat 2-klorbenzotiazola (89) prema virusu gripe H1N1 (EC50 = 6.7 μM).This doctoral thesis describes the synthesis, structural characterization and biological activity of new derivatives of 2-arylbenzimidazole and 2-arylbenzothiazole, hydrazone derivatives of benzothiazole and 1,2,3-triazole derivatives of coumarin and iminocoumarin. In addition to conventional synthetic methods, ecologically acceptable green methods were also used, such as synthesis assisted by microwaves, ultrasound and mechanochemical reactions. Ultrasound-assisted cyclocondensation reaction of prepared O-alkylated benzaldehydes (1‒6) or 1,2,3-triazole derivatives of benzaldehyde (10 and 11) with differently substituted 1,2-diaminobenzenes in the presence of Na2S2O5 as an oxidizing agent, gave new O-alkylated (12 ‒27) and 1,2,3-triazole derivatives of 2-arylbenzimidazole (28‒33).
2-(4-alkoxyphenyl)benzothiazole derivatives (47–55) were synthesized conventionally by O-alkylation reaction of prepared 2-(4-hydroxyphenyl)benzothiazole (40–46) with corresponding aminoalkyl halides in the presence of K2CO3, while 2-(4-alkoxyphenyl)-6-halobenzothiazole derivatives (56–67) were prepared by microwave-assisted O-alkylation reaction of 2-(4-hydroxyphenyl)benzothiazole (43–46). Copper-catalyzed Huisgen 1,3-dipolar cycloaddition reaction of morpholine azide (9) and 2-(4-O-(propargylphenyl)benzothiazole derivatives (68–74) gave 1,2,3-triazole derivatives of benzothiazole (75–81). In order to select the synthetic metod of target 2-arylbenzothiazole derivatives substituted at different position of the benzene ring with 1,2,3-triazole ring (88–117), optimization of the reaction conditions was conducted on a model reaction including conventional synthesis, ultrasound-assisted synthesis and mechanochemical synthesis. Since the liquid assisted mechanochemical reactions gave the highest yields of benzothiazole derivatives (88, 98 and 108) with the shortest reaction time, mechanochemistry was selected as the method for the preparation of 2- and 3-O-(1-aryl-1,2,3-triazolyl))phenylbenzothiazole (88‒117) and
2-(4-O-(1-aryl-1,2,3-triazolyl)phenyl)benzothiazole derivatives (118‒156). Hybrids of benzothiazole and 4-alkylaminobenzene bridged by a hydrazone moiety (169–202) were prepared as an E-isomers using solvent-free mechanochemical synthesis by condensation reaction of 4-alkoxybenzaldehydes (1, 2, 4, 5, 161‒168) and 2-hydrazinylbenzothiazoles (158–160). 1,2,3-triazole iminocoumarin (207–212) and coumarin derivatives (213–223) were synthesized by copper-catalyzed microwave-assisted click reaction of the corresponding azides and terminal alkynes. The structures of the prepared derivatives were confirmed by 1H- and 13C-NMR spectroscopy as well as by two-dimensional methods NOESY, HSQC and HMBC. The antiproliferative activity in vitro of the prepared compounds was evaluated against a range human tumor cell lines as well as on healthy cells. Antibacterial activity in vitro was performed on Gram-positive and Gram-negative bacterial strains including clinically resistant strains of MRSA and VRE. Benzothiazole derivatives with a 1,4-disubstituted 1,2,3-triazole ring (88‒97, 108‒117 and 118–156) were also tested for antiviral activity. In order to establish a possible correlation between antitumor and antioxidative activity, derivatives that showed pronounced antiproliferative activity were evaluated for antioxidant activity in vitro by the DPPH method. Among all the prepared derivatives the most significant antiproliferative activity in vitro showed 6-chloro-2-(4-N,N-diethyl-3-fluorophenyl)benzimidazole (23) (K-562, Z-138, IC50 = 2.0 μM), 6-chloro-2-(4-N,N-diethyl-3-methoxyphenyl)benzothiazole (59) (CFPAC, IC50 = 1.03 μM) and (E)-6-chloro-2-(3-(4-(N,N-dimethylethoxy)-3-fluorophenyl)hidrazonyl)benzothiazole (188) (CAPAN,
IC50 = 0.6 μM, NCI-H460, IC50 = 0.9 μM). The strongest selective antibacterial activity was shown by 2-(4-alkoxyphenyl)-6-chlorobenzimidazole derivatives (15‒17) on Enterococcus faecalis (MIC = 0.25–1 mg/mL) and 6-chloro-2-(4-N,N-diethylphenyl)benzothiazole (50), which showed the most pronounced activity against MRSA strain 13276 (MIC=2 μg/mL). Triazole derivative of 2-chlorobenzothiazole (89) showed the strongest antiviral activity against influenza virus H1N1 (EC50 = 6.7 μM)
Rezultati jedinstvenosti i regularnosti za probleme interakcije fluida i strukture i povezane teme
No full textWe study nonlinear fluid-rigid body interaction problems involving the 3D Navier-Stokes equations for fluid flow and ordinary differential equations for rigid body motion. The fluid and rigid body together occupy a bounded and fixed domain . We examine two initial-boundary value problems: one with incompressible flow and no-slip boundary conditions, and another with compressible flow and inhomogeneous boundary conditions on the boundary . In both cases, we assume that the rigid body does not touch the boundary . In this thesis, we explore three main topics across three chapters. The first two topics deal with the incompressible fluid-rigid body interaction problem. Our goal is to extend the well-known results of weak-strong uniqueness and regularity for the Navier-Stokes equations to the considered fluid-rigid body system. We prove the uniqueness of the weak solution, which satisfies the Prodi-Serrin condition, within a broader class of Leray-Hopf weak solutions. Additionally, we establish that the Prodi-Serrin condition implies the regularity for the fluid velocity and the regularity for the fluid pressure. Moreover, we show that the solutions are if we additionally assume that the acceleration of the rigid body is bounded almost everywhere in time. The final chapter focuses on the motion of a rigid body in a compressible, isentropic, viscous fluid. We consider a scenario where a time-independent fluid velocity is prescribed on the entire boundary , along with a time-independent fluid density on the inflow boundary of . Our objective is to establish the existence of a global-in-time weak solution to the given problem on a time interval where the rigid body does not touch the boundary .Proučavamo nelinearne probleme interakcije fluida i strukture u kojima je tok fluida dan 3D Navier-Stokesovim jednadžbama, dok je struktura kruto tijelo čije je gibanje određeno sustavom običnih diferencijalnih jednadžbi koje opisuju očuvanje linearnog i kutnog momenta. Jednadžbe su u potpunosti povezane preko dinamičkih i kinematičkih uvjeta spajanja. Nadalje, pretpostavljamo da fluid i kruto tijelo zajedno zauzimaju ograničeno i fiksno područje . Razmatramo dvije različite inicijalno-rubne zadaće. U prvom slučaju, tok fluida je zadan inkompresibilnim Navier-Stokesovim jednadžbama, pri čemu je na granici domene postavljen homogeni rubni uvjet. U drugom slučaju, tok fluida određuju kompresibilne Navier-Stokesove jednadžbe, s nehomogenim rubnim uvjetima na granici . Također, u oba slučaja pretpostavljamo da kruto tijelo ne dodiruje rub . U disertaciji istražujemo tri različite teme predstavljene kroz tri poglavlja. Prva tema odnosi se na pitanje jedinstvenosti slabog rješenja problema interakcije inkompresiblinog fluida i krutog tijela. Naš cilj je proširiti poznati rezultat slabo-jake jedinstvenosti za Navier-Stokesove jednadžbe na promatrani sustav fluid-kruto tijelo. Konkretno, dokazujemo da je slabo rješenje koje zadovoljava Prodi-Serrinov uvjet jedinstveno unutar šire klase Leray-Hopfovih slabih rješenja. U ovom poglavlju uzimamo u obzir dvije različite vrste kinematičkih uvjeta povezivanja: uvjet bez klizanja (no-slip) i uvjet klizanja (slip), dok u nastavku pretpostavljamo uvjet bez klizanja. Druga tema je regularnost slabog rješenja iste inicijalno-rubne zadaće. Cilj nam je poopćiti klasični rezultat o regularnosti za 3D inkompresibilne Navier-Stokesove jednadžbe, koji kaže da je slabo rješenje koje zadovoljava Prodi-Serrinov uvjet glatko. Dokazujemo da Prodi-Serrinov uvjet za sustav fluid-kruto tijelo implicira regularnost za brzinu fluida i regularnost za tlak fluida. Nadalje, pokazujemo da su rješenja ako dodatno pretpostavimo ograničenost akceleracije krutog tijela gotovo svugdje u vremenskoj varijabli. Zadnje poglavlje posvećeno je proučavanju gibanja krutog tijela uronjenog u kompresibilni, izentropski, viskozni fluid. Na rubu domene postavljamo vremenski neovisnu brzinu fluida na cijeloj granici i vremenski neovisnu gustoću fluida na dijelu ruba na kojim fluid utječe u područje . Naš cilj je dokazati postojanje slabog rješenja dane zadaće na intervalu na kojem kruto tijelo ne dodiruje rub
Investigation of mechanochemicalreactions by in situ Raman spectroscopy - contributions of physical and chemical factors
No full textU sklopu ove disertacije istražen je utjecaj eksperimentalnih parametara i molekulske strukture na mehanokemijsku reaktivnost. Na modelnoj reakciji jednostupanjske trimerizacije niklovog(II) dibenzoilmetanata sustavno je analiziran utjecaj frekvencije mljevenja, veličine i mase kuglice za mljevenje na kinetiku isključivo mehanički aktivirane transformacije. Uloga i učinak udarca kuglice ispitan je za proces kontinuiranog mljevenja u ukupnoj masi uzorka te na sloju praha, čime su povezane globalna i lokalna kinetika. Uspoređeni su reakcijski mehanizmi u kugličnom mlinu, gdje je dominatna mehanička sila, te u sustavu bez kuglica, odnosno u rezonancijsko-akustičnoj miješalici na modelu sinteze kalkonâ. Pored fizikalnih čimbenika, proučen je utjecaj elektronske strukture i aditiva na mehanosintezu iminâ te aza- Michaelovih adukata. Tim eksperimentima potvrđena je primjenjivost Hammettove korelacije, koncepta razvijenog za reakcije u otopini.As part of this doctoral thesis, the influence of experimental parameters and molecular structure on mechanochemical reactivity was investigated. Using the one-step trimerization of nickel(II) dibenzoylmethanate as a model system, the effects of milling frequency, ball size, and ball mass on the kinetics of a purely mechanically activated transformation were systematically analyzed. The role of ball impacts was examined both within the bulk and on the powder layer, thereby connecting global and local kinetics. Reaction mechanisms were compared between ball milling, where mechanical impact is the dominant force, and a system without milling balls, specifically a resonance acoustic mixer, using chalcone synthesis as a model reaction. In addition to physical factors, the influence of electronic structure and additives on the mechanosynthesis of imines and aza-Michael adducts was studied. These experiments confirmed the applicability of the Hammett correlation, a concept originally developed for solution-phase reactions
Numerički model trošenja uz podmazivanje u strojevima s rotirajućim komponentama
No full textThis research presents a comprehensive numerical framework for wear analysis
of rough surface contacts under lubricated contact conditions, integrating wear,
a deterministic contact and lubrication models. The framework was implemented
within the foam-extend software and relies on the Finite Area Method. It
uses a wear model together with a lubricated contact model, enabling accurate
predictions of contact pressures, surface changes and wear depth across different
lubrication regimes. The model captures surface evolution by iteratively updating
surface geometries based on wear and other calculated contact parameters.
The key features of the framework include the application of a wear model
based on Archard’s Wear Law, a deterministic asperity contact model which allows
the use of measured surface data as input, and a modified Reynolds equation
used to govern lubricant flow with cavitation effects. The developed wear algorithm
combines the aforementioned models and is validated on several test cases,
chosen to closely mimic different tribological scenarios. Single–surface wear was
validated against numerical data from the literature in a Pin–On–Disc test case
showing excellent agreement for contact pressure and surface profile evolution.
Bilateral surface wear was validated using the same test case, with the numerical
results closely matching the numerical data from the literature, demonstrating
the capability of the model to calculate wear for surfaces with different wear coefficients.
Wear of initial line contacts was validated on a Ring–On–Block case,
closely agreeing with numerical data from the literature and following the trends
seen in experiments. The quasi–steady–state wear model was validated on a
reciprocating Ball–On–Flat case, accurately predicting the surface profile and
contact pressure evolution. A Ring–On–Ring test case was used in combination
with surface scans of a real rough surface, validating the ability of the algorithm
to preform wear simulations using direct surface measurements. Finally, the wear
algorithm was used for wear analysis of rough surfaces under lubricated contact
conditions in a lubricated Ball–On–Disc test case using the Shell Turbo T68 oil
as lubricant. The results were analysed for two cases under mixed and nearboundary
lubrication regimes, confirming the ability of the algorithm to predict
contact pressure and surface profile evolution due to wear throughout lubrication
regime transitions.
The implemented wear algorithm was validated against available numerical,
analytical and experimental data for different tribological test cases, confirming
the robustness and applicability of the developed framework for wear analysis
across various tribological scenarios and lubrication regimes.Ovaj rad prikazuje razvoj i validaciju numeričkog modela trošenja površina u
podmazanom kontaktu s relativnim gibanjem, razvijenog u okviru metode kontrolnih
volumena (površina) s ciljem analize mehanizama trošenja u numeričkim
simulacijama strojeva s rotirajućim komponentama.
I. Uvod
Provođenje adekvatne analize trošenja hrapavih površina u kontaktu uz podmazivanje
ključno je za razumijevanje triboloških procesa i optimizaciju kontakta uz
prisutnost trošenja u inženjerskim primjenama. Tradicionalni pristup ispitivanju
trošenja oslanja se na, često financijski zahtjevnim i dugotrajnim, eksperimentalnim
mjerenjima. Sve većom dostupnošću računalnih resursa te napretkom
računalnih metoda, numeričko modeliranje postaje sve više prisutan alat za predviđanje
trošenja površina, pružajući mogućnost uvida u fenomene povezane s
trošenjem te ponašanjem maziva u kontaktu između dvije površine.
Analiza triboloških procesa uključuje istraživanje složenih interakcija između
hrapavih površina, režima podmazivanja te mehanizama trošenja. Trenje i trošenje
hrapavih površina u najvećoj mjeri ovise o kontaktnim tlakovima, debljini
tankog sloja maziva (filma) te materijalnim svojstvima površina između kojih je
ostvaren kontakt. Numeričko modeliranje podmazanih kontakata zahtijeva rješavanje
spregnutog sustava jednadžbi koji opisuju deformaciju površine, strujanje
maziva i evoluciju površine uslijed trošenja.
Ovo istraživanje predstavlja razvoj numeričkog okvira primjenjivog za analizu
trošenja podmazanih hrapavih površina, integrirajući model trošenja površina,
deterministički model površinskog kontakta i model podmazivanja. Numerički je
okvir implementiran u sklopu računalnog paketa foam-extend uz primjenu metode
kontrolnih površina (eng. Finite Area Method). Glavni je cilj istraživanja
točno predvidjeti kontaktne tlakove, visinu trošenja (dubinu potrošenog materijala)
i evoluciju površine u različitim režimima podmazivanja.
II. Numerički modeli i implementacija
Razvijena metodologija za analizu trošenja sastoji se od tri međusobno povezana
numerička modela. Model trošenja razvijen je na temelju Archardovog zakona
trošenja te omogućava proračun visine trošenja (dubine potrošenog materijala) i
volumena trošenja tijekom vremena. Model omogućava analizu utjecaja trošenja
kod nominalno glatkih, ali i hrapavih površina, a razvijen je tako da omogućava
analizu trošenja za slučaj jednostranog i obostranog trošenja površina u kontaktu.
Model je također razvijen kako bi omogućio korištenje snimki topografije površine
(eng. surface scans) kao ulaznih podataka za izračun trošenja i analizu promjene
geometrije kontakta.
Deterministički model kontakta precizno opisuje interakcije topografije hrapavih
površina, uzimajući u obzir učinke površinske hrapavosti na mikroskali. Ova
metoda omogućava precizno određivanje kontaktnih parametara, uključujući kontaktne
tlakove, kontaktne površine i deformacije, a čime se osigurava veća točnost
u odnosu na statističke modele.
Model podmazivanja temelji se na modificiranoj Reynoldsovoj jednadžbi koja
uzima u obzir efekte kavitacije i opisuje strujanje tankog sloja maziva između hrapavih
površina. Reynoldsova jednadžba diskretizirana je primjenom metode kontrolnih
površina (dvodimenzionalne inačice metode kontrolnih volumena), čime
je osigurano očuvanje mase prilikom modeliranja tankih filmova maziva u mješovitom
i hidrodinamičkom režimu podmazivanja.
Ova su tri modela međusobno povezana, omogućujući iterativno ažuriranje
topografije površine na temelju varijabli izračunatih analizom trošenja. Metodologija
je razvijena kako bi se omogućilo korištenje eksperimentalnih podataka o
hrapavosti površina kao ulaznih podataka za numeričke simulacije stvarnih površina
u uvjetima podmazanog kontakta.
III. Validacija i verifikacija
Provedena je detaljna validacija i verifikacija kako bi se osigurala točnost i robusnost
implementiranih modela. Numerički rezultati uspoređeni su s postojećim
analitičkim, numeričkim i eksperimentalnim podacima dostupnim u literaturi.
Testni slučajevi na kojima je provedena validacija razvijeni su kako bi se što
vjernije reproducirali različiti tribološki eksperimenti.
Model trošenja jedne površine validiran je na testnom slučaju u kojem valjčić
kruži po disku („valjčić po disku“, eng. Pin–On–Disc) pomoću numeričkih
te analitičkih podataka iz literature. Izračunate vrijednosti kontaktnih tlakova,
promjena površine uslijed trošenja te dubine i volumena potrošenog materijala,
izvrsno se podudaraju s analitičkim i numeričkim rezultatima iz literature. Korištenjem
istog testnog slučaja „valjčić po disku “također je ispitan model bilateralnog
trošenja, potvrđujući primijenjivost modela za točno predviđanje trošenja
obje kontaktne površine. Testni slučaj prstena koji rotira oslonjen o ravan blok
(„prsten po bloku“, eng. Ring–On–Block) korišten je kako bi se analiziralo trošenje
u uvjetima linijskog kontakta, gdje su numerički rezultati pokazali izvrsno
podudaranje s numeričkim rezultatima iz literature te vrlo dobro podudaranje
s trendovima vidljivim iz eksperimentalnih podataka. Kvazistacionarni model
trošenja validiran je pomoću testnog slučaja kuglice koja se linearno pomiče po
ploči („kuglica po ploči“, eng. Reciprocating Ball–On–Flat), potvrđujući primijenjivost
modela za predviđanje trošenja kod cikličkih gibanja površina u kontaktu
uz izvrsno podudaranje s numeričkim rezultatima iz literature. Validacija trošenja
hrapavih površina provedena je pomoću testnog slučaja glatkog prstena koji
rotira prislonjen uz hrapavi prsten („prsten po prstenu“, eng. Ring–On–Ring),
gdje su korišteni eksperimentalno izmjereni profili površina. Numerički model
uspješno je predvidio trošenje na temelju stvarnih snimki topografije površine.
Dodatno, provedena je analiza trošenja u podmazanom kontaktu koristeći testni
slučaj hrapave kuglice koja rotira po glatkom disku („kuglica po disku “, eng. Ball–
On–Disc) uz korištenje mazivog ulja Shell Turbo T68, čime je pokazano kako je
razvijenu metodologiju za analizu trošenja moguće koristiti i za proračun trošenja
u mješovitom i graničnom režimu podmazivanja. Pokazano je kako različiti režimi
podmazivanja značajno utječu na raspodjelu kontaktnih tlakova, pri čemu prelaskom
u hidrodinamički režim dolazi do smanjenja izravnog kontakta površina i
do smanjenja trošenja. Analizirajući rezultate navedenih testnih slučajeva, pokazano
je kako razvijena metodologija za proračun trošenja materijala pokazuje vrlo
dobro podudaranje s podacima dostupnim u literaturi, potvrđujući primjenjivost
modela u stvarnim tribološkim sustavima.
IV. Zaključak
Ovo istraživanje predstavlja razvoj i implementaciju numeričkog okvira namijenjenog
za analizu trošenja, koji se temelji na sprezi modela trošenja, determinističkog
modela kontakta i modela podmazivanja za kontakt hrapavih površina.
Numerički je okvir implementiran unutar programskog paketa otvorenog koda
foam-extend, a temelji se na metodi kontrolnih površina. Razvijena numerička
metodologija omogućava predviđanje visine trošenja (dubine potrošenog materijala),
evolucije površine uslijed trošenja te kontaktnih tlakova i drugih veličina
značajnih za analizu trošenja u različitim režimima podmazivanja, kao i u suhom
kontaktu
The influence of Dapagliflozin on foot microcirculation in patients with type 2 diabetes with and without peripheral arterial disease
No full textKod oboljelih od šećerne bolesti (ŠB) višestruko je povećan rizik od razvoja periferne arterijske bolesti (PAB) uz značajno lošiju prognozu, u smislu usporenog cijeljenja rana, razvoja gangrene i amputacija, u odnosu na pacijente s PAB a bez ŠB uz jednaki kardiovaskularni morbiditet i mortalitet. SGLT2 inhibitori, osim antihiperglikemijskog učinka, značajno smanjuju rizik od velikih štetnih kardiovaskularnih događaja, hospitalizacije zbog srčanog popuštanja, kardiovaskularnog i ukupnog mortaliteta te od progresije kronične bubrežne bolesti. Iako SGLT2 inhibitori pokazuju brojne povoljne učinke na mikrocirkulaciju, terapija SGLT2 inhibitorima povećava rizik od amputacija donjih ekstremiteta, no preporuke stručnih društava vezane uz terapiju SGLT2 inhibitorima, kod pacijenata s DFU nisu usuglašene. Cilj ovog istraživanja bio je utvrditi, dolazi li do promjena u mikrocirkulaciji tj. tkivnoj oksigenaciji stopala, koja je mjerena transkutanom tkivnom oksimetrijom (TcPO2), kod pacijenata sa ŠBT2 i PAB te bez PAB-a uz usporedbi s pacijentima koji imaju PAB a uzimaju druge antidijabetike (metformin, DPP-4 inhibitori, gliklazid, inzulin). Rezultati našeg istraživanja su pokazali da je učinak SGLT- 2 inhibitora dapagliflozina na mikrocirkulaciju stopala heterogen. Kod pacijenata sa hipoksijom stopala (TcPO2 = 40mmHg), a uzimali su dapagliflozin, došlo je do minimalnog poboljšanja mikrocirkulacije stopala (0.24, 1.22 mm Hg), bez značajne razlike između grupa. U grupi pacijenata s PAB koji su uzimali dapagliflozin, utvrđen je statistički značajno veći broj pacijenata kod kojih se mikrocirkulacija pogoršala (p = 0.037), dok u grupi bez PAB liječenoj dapagliflozinom i grupi s PAB liječenoj drugim antidijabeticima nije nađena značajna razlika između navedenih podgrupa. Ovi rezultati govore u prilog važnosti evaluacije dinamike promjene nalaza TcPO2 u procjeni ugroženosti stopala kod pacijenata sa ŠBT2 i PAB. Rezultati istraživanja ukazuju da među pacijentima sa ŠBT2 i PAB terapija dapagliflozinom značajno češće dovodi do pogoršanja, nego do poboljšanja mikrocirkulacije tj. tkivne oksigenacije stopala uz klinički značajan intenzitet pogoršanja nalaza. Potrebna su daljnja istraživanja, na većem broju pacijenata s PAB i TcPO2 = 40mmHg) at baseline and follow-up who were taking dapagliflozin, there was minimal improvement in foot microcirculation (0.24, 1.22 mm Hg), with no significant difference between the groups. In the group of patients with PAD taking dapagliflozin, a significantly higher number of patients with worsening microcirculation was found (p = 0.037), while in the group without PAD treated with dapagliflozin and in the group with PAD treated with other antidiabetic drugs, no significant difference was found between the mentioned subgroups. These results emphasise the importance of evaluating the dynamics of changes in TcPO2 findings when assessing foot risk in patients with T2DMand PAD. The results of the study suggest that dapagliflozin therapy worsens rather than improves microcirculation, i.e. tissue oxygenation of the feet, in patients with T2DM and PAD, with the intensity of the worsening being clinically significant. Further studies in a larger number of patients with PAD and TcPO2 < 40 mm Hg are needed to clarify the effects of SGLT2 inhibitors on microcirculation and tissue oxygenation of the feet and the potential risk of amputation
Procjena učinka različitih predtretmana cakline na snagu svezivanja pečatne smole
No full textThe success rate of fissure sealants depends on factors such as retention associated with the quality of adhesion between the sealant material and the enamel. Different types of enamel surface pretreatments have been used. The aim of this in vitro study is to evaluate the bond strength of pit and fissure sealant with pretreatment of different laser pulse mode and additional acid etching. Forty-two healthy molars and premolars were collected for this study. After the cleaning and disinfection, they were randomly divided in 6 groups (n=7). Group 1: Quantum Square Pulse (QSP) mode or Adaptive Structured Pulse (ASP Group 2: Medium-Short Pulse (MSP) mode, Group 3: Super Short Pulse (SSP) mode, Group 4: QSP + acid etching, Group 5: MSP + acid
etching, Group 6: SSP + acid etching. The laser conditioning of enamel was carried out using Fotona Lightwalker Er:YAG laser (2940 nm), an H14 handpiece with a conical sapphire fibre tip (13 to 0.8/8 mm), and power output 120 mJ, 10 Hz. Additional acid etching using 37% phosphoric acid was used. After the pretreatment procedures they were sealed with resin based composite fissure sealant (Helioseal F, Ivoclar Vivadent AG, Schaan, Liechtenstein). All teeth were cut in slices 1-1.5 mm thick, and at least 6 mm long for the performance of microtensile bond strength. Stereomicroscope analysis of failure mode was performed as well.
The highest obtained bond strength was measured using laser etching with MSP mode combined with acid etching (36.09). This combination was showing significantly higher bond strength in comparison to the other two combinations (SSP + ETCH, p<0.001; QSP + ETCH, p<0.001). The comparisons revealed significant differences in bond strength between various pretreatment groups, with QSP and MSP demonstrating superior bond strength compared to SSP. However, respective laser etching using QSP did not significantly improve bond strength when combined with acid etching. These findings contribute to the growing body of literature
on pretreatment methods for fissure sealants and emphasize the potential benefits of alternative approaches such as QSP and MSP. Future studies with larger sample sizes and comprehensive evaluations are warranted to further elucidate the role of laser etching in enhancing the effectiveness of fissure sealant placement. CONCLUSION: MSP laser etching showed the highest bond strength. Thus, interestingly, MSP with 140 µs pulse mode might be the preferred choice as pretreatment procedure.UVOD: Fisure su vitalna preventivna mjera u stomatologiji, osmišljena da zaštiti okluzalne površine molara od karijesnih lezija. Učinkovitost ovih sealanta u velikoj mjeri ovisi o njihovom zadržavanju, što je prvenstveno određeno kvalitetom adhezije između materijala sealanta i površine emajla. Različiti prethodni tretmani površine emajla korišteni su za
poboljšanje ove vrste veze, uključujući kiselinsko jetkanje i laserske tretmane. Nedavni napredak u laserskoj tehnologiji uveo je različite pulsne načine koji mogu utjecati na svojstva površine emajla, potencijalno poboljšavajući adheziju sealanta. Cilj ove in vitro studije je ocijeniti čvrstoću veze između sealanta za fisure i emajla prethodno obrađenog različitim
laserskim pulsnim načinima, uz tradicionalno kiselinsko jetkanje. Istraživanjem ovih varijabli, ova studija želi pružiti uvid u optimizaciju primjene sealanta za fisure, što će na kraju doprinijeti boljim kliničkim ishodima u prevenciji karijesa.
METODE: Za ovu studiju prikupljeno je četrdeset i dva zdrava molara i premolara. Nakon čišćenja i dezinfekcije, zubi su nasumično podijeljeni u 6 grupa (n=7):
¥ Grupa 1: Quantum Square Pulse (QSP) ili Adaptive Structured Pulse (ASP)
¥ Grupa 2: Medium-Short Pulse (MSP)
¥ Grupa 3: Super Short Pulse (SSP)
¥ Grupa 4: QSP + kiselinsko jetkanje
¥ Grupa 5: MSP + kiselinsko jetkanje
¥ Grupa 6: SSP + kiselinsko jetkanje
Lasersko kondicioniranje emajla izvedeno je pomou Fotona Lightwalker Er lasera (2940 nm), H14 ručne glave, s koničnim safirnim vlaknom (13 do 0,8/8 mm) i izlaznom snagom od 120 mJ, 10 Hz. Dodatno, korišteno je kiselinsko jetkanje s 37% fosfornom kiselinom. Nakon postupaka pretreatmenta, zubi su zapečaćeni smolastim kompozitnim sealantom za fisure (Helioseal F, Ivoclar Vivadent AG, Schaan, Liechtenstein). Svi zubi su rezani na tanke kriške debljine 1-1,5 mm i dužine najmanje 6 mm kako bi se izvela mikrotenzijska ispitivanja čvrstoće veze. Također je provedena stereomikroskopska analiza načina neuspjeha.
REZULTATI: Najviša izmjerena čvrstoća veze postignuta je korištenjem laserskog jetkanja s MSP načinom u kombinaciji s kiselinskim jetkanjem (36,09). Ova kombinacija pokazala je značajno veću čvrstoću veze u usporedbi s obje druge kombinacije (SSP + ETCH, p<0,001; QSP + ETCH, p<0,001).
RASPRAVA: Uporedbe su otkrile značajne razlike u čvrstoći veze između različitih grupa pretreatmenta, pri čemu su QSP i MSP pokazali superiornu čvrstoću veze u odnosu na SSP. Međutim, lasersko jetkanje korištenjem QSP nije značajno poboljšalo čvrstoću veze kada se kombiniralo s kiselinskim jetkanjem. Ovi nalazi doprinose rastućem broju literature o
metodama pretreatmenta za fissure sealante i naglašavaju potencijalne prednosti alternativnih pristupa poput QSP i MSP. Buduće studije s većim uzorcima i sveobuhvatnim evaluacijama su neophodne za daljnje razjašnjavanje uloge laserskog jetkanja u poboljšanju učinkovitosti primjene sealanta za fisure.
ZAKLJUČAK: MSP lasersko jetkanje pokazalo je najvišu čvrstoću veze. Stoga, zanimljivo, MSP s pulsnim načinom od 140 µs mogao bi biti preferirani izbor kao postupak pretreatmenta
Example and practice of virtue of life : the interpretation of Marulić's Institutions in the key of the philosophy of shaping life
No full textNaš rad se temelji na hermeneutičkom pristupu kojim se Marulićevo djelo Institucija tumači u ključu filozofije kao umijeća življenja, odnosno oblikovanja načina života. Pritom polazimo od triju ključnih pojmova: duhovne vježbe, tehnologija sebstva i antropotehnika. Navedeni koncepti predstavljaju srž asketološkog obrata u suvremenoj filozofiji, čiji su istaknuti predstavnici Pierre Hadot, Michel Foucault i Peter Sloterdijk. Cilj nam je uočiti i opisati određene elemente filozofske askeze koje je Marulić koristio prilikom pisanja vlastitoga djela, zamišljenog kao priručnik za oblikovanje kršćanskoga načina života po uzoru na svece. Kako bi čitatelja priveo k blaženom i čestitom životu, Marulić se, prvenstveno posredstvom patrističke književnosti i srednjovjekovne hagiografije, oslanjao na niz duhovnih tehnika i vježbi koje pomažu izgraditi evanđeoski način života, pojmljen kao nasljedovanje Krista. Znatan dio tih duhovnih vježbi potječe iz antičke filozofske tradicije, uglavnom platonističke i stoičke, te je kasnije modificiran i prilagođen obilježjima i ciljevima kršćanske duhovnosti. Budući da se Marulićev magnum opus De institutione obično interpretiralo kao hagiografsko djelo namijenjeno propovjednicima ili kao moralno-didaktički priručnik, gotovo da nema naznaka stručne analize koja bi spomenuto djelo tumačila, na njegovoj kompozicijskoj i sadržajnoj razini, u svjetlu antičkih filozofskih duhovnih vježbi ili pak duhovnog vodstva. Stoga držimo kako će naš specifičan pristup tom djelu omogućiti produbljenije razumijevanje njegova sadržaja, jasnije poimanje njegove žanrovske pripadnosti kao i bogate intertekstualne slojevitosti. Naime, asketološka i psihagogička pragmatika, kojom se Marulić rukovodio pišući Instituciju, uvjetuje kako tematsku raspodjelu i pripovjedni stil tako i narativnu strategiju i strukturu samoga djela. Značenje pojedinih pripovjednih sekvenci i anegdotskih minijatura uvijek je podređeno osnovnoj spiritualnoj svrsi i uklopljeno u obuhvatniju strukturu koja polazi od obraćenja a završava vječnim blaženstvom u zajedništvu s Bogom.Our work is based on a hermeneutical approach that interprets Marulić's work Institutions in the key of philosophy as the art of living, or shaping the way of life. In doing so, we start from three key concepts: spiritual exercises, technology of the self and anthropotechnics. These concepts are at the heart of the ascetical turn in contemporary philosophy, whose prominent representatives are Pierre Hadot, Michel Foucault and Peter Sloterdijk. Our aim is to identify and describe certain elements of philosophical asceticism that Marulić used when writing his own work, conceived as a manual for shaping the Christian way of life according to the example of the saints as a role models. In order to lead the reader to a blessed and virtuous life, Marulić relied, primarily through patristic literature and medieval hagiography, on a series of spiritual techniques and excercises that help build an evangelical way of life, understood as an imitation of Christ. A significant part of these spiritual exercises originates from the ancient philosophical tradition, mainly Platonic and Stoic, and was later modified and adapted to the features and goals of Christian spirituality. Since Marulić's magnum opus De institutione was usually interpreted as a hagiographic work intended for preachers or as a moral-didactic handbook, there is almost no indication of an expert analysis that would interpret the mentioned work, on its compositional and content level, in the light of ancient philosophical spiritual exercises or spiritual guidance. Therefore, we believe that our specific approach to this work will enable a deeper understanding of its content, a clearer understanding of its genre affiliation as well as its rich intertextual layering. Namely, ascetological and psychagogical pragmatics, which Marulić was guided by when writing the Institution, determines both the thematic distribution and narrative style, as well as the narrative strategy and structure of the work itself. The meaning of individual narrative sequences and anecdotal miniatures is always subordinated to a basic spiritual purpose and incorporated into a more comprehensive structure that begins with conversion and ends with eternal bliss in communion with God