Density functional theory calculation of the optical properties of graphene quantum dots

Graphene quantum dots (GQDs) are class of nanoparticles exhibiting unique and tunable electronic, optical, chemical and structural properties owing to their small size and quantum confinement and edge effects. GQDs most prominent characteristics are high photoluminescence, photostability, excellent photobleaching resistance, low citotoxicity, good biocompatibility, exceptional electrochemical activity and physicochemical stability, making them suitable for a wide range of applications, from biosensing and fluorescence bioimaging usage, photodynamic therapy, to optoelectronic, susteanable agricultural and environmental applications. Using density functional theory (DFT) we demonstrate that the optical properties of the GQDs can be sensitively tuned by its size, shape, edge configuration, attached chemical functionalities.Twenty-First Young Researchers’ Conference - Materials Science and Engineering: Program and the Book of Abstracts; November 29 – December 1, 2023, Belgrade, Serbi

Final Year University Students’ Beliefs about Future Employment Relationships

AbstractPsychological contract is important construct to understand continuing changes in employment relationships. In that way, anticipatory psychological contract (APC) presents valuable framework to understand graduate students’ beliefs about future employment relationships. Accordingly, the aim of this study was to examine ACP content, i.e. beliefs about employee contributions and employer inducements in the employment relationship. The sample consisted of 271 final year university students form Macedonia and from Serbia enrolled following study programs: psychology and medicine philology/literature and technology and informatics. Questionnaire with 48 statements was administered to measure ACP content. Two-way ANOVA and loglinear analysis were conducted for data analyzing. It was found that students preparing for various occupations from two countries significantly differ in the expressed beliefs about their contributions in the future employment relationship and in their belief about employer inducements in that relationship. In general, surveyed students reported stronger beliefs about employer inducements than about their contributions at work

Self-assembly of carbon based nanoparticles films by Langmuir-Blodgett method

Carbon nanoparticles are a class of materials with extraordinary properties. In the past three decades, four major types of carbon nanoparticles were synthesized and investigated: fullerenes, carbon nanotubes, graphene and carbon quantum dots. One of the main properties of such materials is their hydrophobic nature. At the same time, Langmuir–Blodgett (LB) method the for deposition of thin films of hydrophobic materials provides the possibility to design thin films of different carbon-based nanoparticles with special architectures and features enabling their usage in various fields, particularly in electronics and biomedicine. In this review, the state of art of LB thin films of four types of carbon-based nanoparticles and their application in electronics and biomedicine are presented. The breakthrough in this field was finally achieved by application of carbon quantum dots soluble in solvents optimized for LB deposition

Informatička i informacijska pismenost u području sestrinstva kao preduvjet za održivo financijsko poslovanje

This paper examines information technology and information literacy of employees as one of the more essential prerequisites for creating smart hospitals, which are, on the other hand, a prerequisite for sustainable financial operations. Since nursing is the backbone of every hospital, research is focused on the nursing profession. Namely, if medical personnel do not know the basics of information and communication technology (ICT) and are incapable of recognizing, finding and structuring information into new knowledge and exchanging it with colleagues, an intelligent hospital is impossible, and the business is worse. For this reason, research was conducted to determine the state of computer and information literacy in the nursing field in hospitals in north-western Croatia. It was carried out in 2021, which determined the ratio of administrative work and health care and examined the level of ICT knowledge of nurses and technicians. Analysing the secondary, higher and higher medical school curriculum determined the current situation and required improvements. The research results showed that computer and information literate staff spend less time on administration; they estimate that there is not enough content on computer literacy in the existing curricula. The hospital\u27s operations will also be efficient because the competencies of the nurses will enable better implementation of business processes and a better financial result for the hospital.U ovom radu ispituje se informatička i informacijska pismenost zaposlenika kao jedan od bitnijih preduvjeta za stvaranje pametnih bolnica, koje su s druge strane preduvjet održivog financijskog poslovanja. Budući da je sestrinstvo okosnica svake bolnice, istraživanja su usmjerena na sestrinsku profesiju. Naime, ako medicinsko osoblje ne poznaje osnove informacijsko-komunikacije tehnologije (IKT) i ne mogu prepoznati, pronaći i strukturirati informacije u nova znanja i razmijeniti ih s kolegama, nije moguća ni pametna bolnica, a time je lošije poslovanje. Iz tog razloga provedeno je istraživanje s ciljem utvrđivanja stanja informatičke i informacijske pismenosti u području sestrinstva u bolnicama sjeverozapadne Hrvatske. Provedeno je tijekom 2021, kojim je utvrđen omjer administrativnih poslova i zdravstvene zaštite te je ispitana razina informatičkog znanja medicinskih sestara i tehničara. Analizom nastavnog plana i programa u srednjim, višim i visokim medicinskim školama utvrđeno je trenutno stanje i potrebna poboljšanja. Rezultati istraživanja pokazali su da informatički i informacijski pismeno osoblje troši manje vremena na administraciju, procjenjuju da u postojećim nastavnim planovima i programima nema dovoljno sadržaja o informatičkom opismenjavanju. Ukoliko se IKT bude učinkovitije i djelotvornije koristio u području sestrinstva, tada će i poslovanje bolnice biti učinkovito jer će kompetencije medicinskih sestara omogućiti bolje provođenje poslovnih procesa i bolji financijski rezultat bolnice

Važnost informacijske pismenosti za upravljanje zdravstvenim sustavom Republike Hrvatske

U ovom radu objašnjava se važnost informacijske pismenosti za upravljanje informacijskim zdravstvenim sustavom. Radi se o tome da je informacijska pismenost menadžmenta, a to znači prepoznavanje potrebnih informacija, poznavanje efikasnog načina dolaženja do njih, strukturiranje informacija u novo znanje te diseminacija informacija onima kojima su potrebne, preduvjet bez kojeg nema ovladavanja menadžmenta s informacijskom tehnologijom. Drugim riječima, bez informacijskog opismenjavanja menadžmenta, on nije u mogućnosti pravilno valorizirati ulogu informatičke tehnologije u poslovanju, ne može ju kvalitetno uporabiti kako bi ona zaista bila podrška u odlučivanju. U ovom radu predložen je pristup ovladavanja informacijskom tehnologijom od strane menadžmenta preko primjene okvira COBIT. Isto tako predstavljeno je istraživanje u kojem se kroz ispunjavanje kontrolnih ciljeva unutar svakog COBIT procesa može odrediti stupanj zrelosti ovladavanja menadžmenta s informacijskom tehnologijom, a time i stupanj njihove informacijske pismenosti

Ispitivanje genotoksičnosti 8-CI-cAMP u dva in vivo testa na miševima soja BALB/c

The antitumor agent 8-CI-cAMP (8-chloro-cyclic adenosine monophosphate) is the most potent site-selective analogue of cAMP. It acts primarily by selective down-regulation of regulatory sub-units of cAMP-dependent protein kinases. This results in reversion of the neoplastic predominance of PK-I type over PK-II type protein kinase back to the ratio more typical to of the normal phenotype. The differential activity of 8-CI-cAMP towards protein kinase isozymes leads to inhibition of cell growth, differentiation and neoplastic reversion of a wide variety of cancer cell lines. Since 8-CI-cAMP has been investigated as a new potential anticancer drug with no previous studies of its mutagenic and clastogenic effects, we have investigated the genotoxicity of 8-CI-cAMP. Genotoxic effects were estimated by the bone marrow micronucleus assay and the occurrence of morphological chromosome lesions in adult mice (BALB/c strain). 8-CI-cAMP was administered intraperitoneally (i.p) in three doses, 10 mg/kg b.w.; 90 mg/kg b.w. and 160 mg/kg b.w., with saline solution as a negative control and cyclophosphamide, a known mutagen and clastogen as a positive control at twenty four hour intervals during a seven day period. Micronucleus test results showed a consistent dose-dependent pattern. Thus, with increase of the dose (10 mg/kg b.w., 90 mg/kg b. w. and 160 mg/kg b.w.) there was an increase in the frequency of micronuclei in polychromatic erythrocytes (4.88 ± 0.35; 8.32 ± 0.57; 11.75 ± 0.37) compared to the negative control (2.04 ±0.28). Using chromosome aberrations as an indicator of genotoxic potential, 8-CI-cAMP in all three doses (10 mg/kg b.w.; 90 mg/kg b.w. and 160 mg/kg b.w.) produced karyotype transformation of mouse bone marrow cells. 8-CI-cAMP induced structural chromosome aberrations as lesions (2.87 0.14; 4,37 0.14 i 5.25 0.35), interruptions (9±0.1; 12.37±0.26 i 13.37±0,33), ring chromosomes (3.62 0.21; 2.5±0,07 i 2.5±0.07), accentrics (10±0.49; 16.5±0.45 i 18.37±0.54) and Robertsonian translocations (7.12±0.26 ;9 0.1 i 11.24 ±0.18) as well as numerical chromosome aberrations of the aneuploidal type (36 5± 0.74; 60.25±0.24 i 85.62±0.5) and polyploidy (7±0.24; 5.5+0.27 / 5.87±0.14). These results demonstrate the genotoxic potential of the investigated substance.Antitumorski preparat 8-CI-cAMP (8-hloro-ciklični adenozin monofosfat) je najpotentniji analog AMP koji deluje primamo na modulaciju cAMP - zavisne protein kinaze dovodeći do inhibicije regulatornih subjedinica. Rezultat takvog dejstva je smanjenje dominantnog tipa PK-I protein kinaze u kanceroznim ćelijama nad drugim tipom PK-II protein kinaze, u odnosu na međusobni nivo PK-I I PK-II koji se nalaze u normalnim ćelijama. Ciklični 8-CI-AMP je analog koji ima izuzetnu anti-neoplastičnu aktivnost sa efektom restauracije, diferencijacije i reverzne transformacije kanceroznih ćelija miša i čoveka. Sa stanovišta mogućeg mutagenog i genotoksičnog efekta 8-CI-cAMP nije dovoljno istražen. Zato je i cilj ovog rada bio da se primenom citogenetičkog i mikronukleus testa, na ćelijama kostne srži miša BALB/c soja, ispita genotoksični efekat 8-CI-cAMP u tri dozna režima (10 mg/kg t.m; 90 mg/kg t.m. i 160 mg/kg t.m.). Pored eksperimentalnih grupa životinja u eksperimentu su uspostavljene i negativna kontrola koju su činile jedinke tretirane sa fiziološkim rastvorom, kao i pozitivna kontrola životinja koje su tretirane sa poznatim klastogenom i mutagenom-ciklofosfamidom u dozi od 40 mg/kg t.m. Rezultati ispitivanja pokazuju konzistetni dozno-zavisni obrazac primenom mikronukleus testa. Sa rastom doze (10 mg/kg t.m ; 90 mg/kg t.m. i 160 mg/kg t.m.) raste i broj mikronukleusa u polihromatofilnim eritrocitima (4,88 ±0,35; 8,32±0,57; 11,75±0,37) u odnosu na kontrolnu grupu (2,04±0,28). Testirane rastuće doze 8-CI-cAMP u citogenetičkom testu in vivo pokazuju sposobnost transformacije kariotipa ćelija kostne srži BALB/c miševa u vidu struktumih hromozomskih aberacija tipa lezija (2,87±0,14; 4,37±0,14; 5,25±0,35), prekida (90,1; 12,37±0,26; 13,37±0,33), ring hromozoma (3,62+0,21; 2,5±0,07; 2,5±0,07), acentrika (100,49; 16,5±0,45; 18,37±0,54) i Robersonovih translokacija (7,12±0,26; 90,1; 11,24±0,18) i numeričkih hromozomskih aberacija tipa aneuploidija (36,5±0,74; 60,25±0,24; 85,62±0,5) i poliploidija (70,24; 5,5±0,21; 5,87±0,14) što ukazuje na postojanje genotoksičnog potencijala ispitivane supstance

Dojenje iz ugla dečjeg stomatologa

Current recommendations by the European Academy of Paediatric Dentistry, American Academy of Paediatric Dentistry, and International Association of Paediatric Dentistry advocate weaning from breast milk and avoiding unrestricted breastfeeding after the eruption of primary teeth in order to lower the risk of early childhood caries (ECC). However, World Health Organization, American Academy of Paediatrics and nutritional recommendations support exclusive breastfeeding up to six months of age, following continued breastfeeding along with appropriate complementary foods, favouring unrestricted and prolonged breastfeeding even beyond the age of two. The purpose of this review is to discuss current data in the literature regarding the association between breastfeeding and ECC in order to address this problem and to provide consistent recommendations. PubMed search revealed possible link between breastfeeding and ECC, however without evidence strong enough to establish the appropriate oral health preventive recommendation. Having in mind known benefits of breastfeeding, it is advisable to adhere to current paediatric guidelines which promote unrestricted breastfeeding as long as it is mutually desired by mother and child. This recommendation doesn't exclude but complements the prevention and timely treatment of ECC. Furthermore, there is a need to highlight the importance of education of parents and health care providers about the ECC risk factors, identification of initial lesions and consequences. Further research regarding this issue is needed.Savremene preporuke Evropske i Američke akademije dečjih stomatologa i Međunarodnog udruženja dečjih stomatologa savetuju postepeni prekid dojenja nakon nicanja mlečnih zuba kako bi se smanjio rizik od nastanka karijesa ranog detinjstva (KRD). Sa druge strane, preporuke Svetske zdravstvene organizacije, preporuke Američke akademije pedijatara i stručnjaka iz oblasti ishrane prepoznaju brojne kratkoročne i dugoročne pozitivne efekte dojenja i podržavaju isključivo dojenje do uzrasta od šest meseci, a zatim postepeno uvođenje čvrste hrane sa nastavkom dojenja uz neograničeno i dojenje na zahtev do druge godine deteta i duže. Cilj ovog preglednog rada je bio da se analiziraju savremeni podaci u literaturi o uticaju dojenja na nastanak KRD, kako bi se doprinelo formiranju jedinstvenog stava i pružila jasna informacija majkama kako prevenirati KRD. Na osnovu pretraživanja Pub Med baze podataka, uočava se da postoji povezanost između dojenja i KRD, ali nije dovoljno argumentovano koje su najbolje mere u prevenciji karijesa. Imajući u vidu poznate pozitivne efekte dojenja, smatra se da je preporučljivo pratiti savremene pedijatrijske preporuke koje savetuju neograničeno dojenje koliko God to uzajamno prija majci i detetu. Ipak, potrebno je imati u vidu neophodnost ranih preventivnih poseta dečjem stomatologu i edukacije zdravstvenih radnika radi adekvatnih i blagovremenih saveta o higijeni usne u duplje i ishrani kako bi se izbegao nastanak karijesa ranog detinjstva i omogućilo blagovremeno dijagnostikovnje inicijalnih lezija. Neophodna su dalja istraživanja u ovoj oblasti

Antibacterial and Antibiofouling Activities of Carbon Polymerized Dots/Polyurethane and C60/Polyurethane Composite Films

The cost of treatment of antibiotic-resistant pathogens is on the level of tens of billions of dollars at the moment. It is of special interest to reduce or solve this problem using antimicrobial coatings, especially in hospitals or other healthcare facilities. The bacteria can transfer from medical staff or contaminated surfaces to patients. In this paper, we focused our attention on the antibacterial and antibiofouling activities of two types of photodynamic polyurethane composite films doped with carbon polymerized dots (CPDs) and fullerene C60. Detailed atomic force, electrostatic force and viscoelastic microscopy revealed topology, nanoelectrical and nanomechanical properties of used fillers and composites. A relationship between the electronic structure of the nanocarbon fillers and the antibacterial and antibiofouling activities of the composites was established. Thorough spectroscopic analysis of reactive oxygen species (ROS) generation was conducted for both composite films, and it was found that both of them were potent antibacterial agents against nosocomial bacteria (Klebsiela pneumoniae, Proteus mirabilis, Salmonela enterica, Enterococcus faecalis, Enterococcus epidermis and Pseudomonas aeruginosa). Antibiofouling testing of composite films indicated that the CPDs/PU composite films eradicated almost completely the biofilms of Pseudomonas aeruginosa and Staphylococcus aureus and about 50% of Escherichia coli biofilms

Investigations of genotoxic potential of levamisole hydrochloride in bone marrow cells of Wistar rats

An experiment was performed under in vivo conditions on bone marrow cells of Wistar rats. The following doses of levamisole hydrochloride were tested: a therapeutic dose of 2.2 mg/kg bm, a dose of 4.4 mg/kg bm, LD50 -25% mg/kg bm, and LD50 -75% mg/kg bm. We followed the effect of levamisole hydrochloride on kinetics of the cell cycle and the appearance of structural and numeric changes in chromosomes in bone marrow cells. The therapeutic dose of levamisole of 2.2 mg/kg bm exhibited a capability to increase mitotic activity in the observed cells, thus confirming knowledge of the immunostimulative effect of this dose of the medicine under in vivo conditions. The other tested doses of levamisole in this experiment, observed in comparison with the control group, had an opposite effect, namely, they caused a reduction in the mitotic activity of bone marrow cells. All the examined doses in vivo exhibited the ability to induce numeric (aneuploid and polyploid) and structural (lesions, breaks and insertions) chromosomal aberrations. It can be concluded on the grounds of these findings that the examined doses have a genotoxic effect