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Volume-averaging of a measured detector response is a known problem in small photon beam dosimetry. This affects the reading of detectors and erroneously makes wider the penumbra region of a measured dose profile which results in an underestimation of the absorbed dose on the beam central axis. To account for this, the measured response must be corrected by the volume averaging correction factor, calculated using Kawachi formalism. However, due to the difference in radiation field geometry, this formalism must be modified to be applicable to Gamma Knife (Elekta, Stockholm, Sweden). The purpose of this work was to determine the volume averaging correction factors for different ionization chambers and field sizes in narrow Co-60 beams used by Gamma Knife Icon. Small-volume ionization chambers that were studied are: Semiflex TM31010 V=125 mm3, PinPoint TM31014 V=15 mm3, PinPoint 3D TM31016 V=16 mm3 (PTW, Freiburg, Germany), RAZOR chamber V=10 mm3, and RAZORnano chamber V=3 mm3 (IBA Dosimetry, Schwarzenbruck, Germany). To determine a volume averaging correction for different detectors a 3D elliptical dose model was implemented using normalized dose profiles provided by Elekta (Sweden). With fitted dose profiles and an elliptical 3D dose model, an analytical expression and visualization of different field sizes were obtained using MATLAB (TheMathWorks Inc., USA). Using numerical integration (Simpson's rule), we were able to determine the volume averaging correction factors as a function of different field sizes. Semiflex chamber has the largest volume averaging correction factor: 1.006, 1.042, and 1.627 for 16, 8, and 4 mm field sizes respectively. Furthermore, the corrections for the PinPoint ionization chamber are 1.005, 1.011, and 1.181 ; for PinPoint 3D, the corrections are 1.003, 1.005, and 1.057 for 16, 8, and 4 mm field sizes respectively. The corrections for the RAZOR chamber are 1.004, 1.006, and 1.074 while the RAZORnano chamber has corrections of 1.003, 1.003, and 1.025 for 16, 8, and 4 mm field sizes respectively. This work has illustrated the possibility to determine volume averaging correction factors for narrow photon beams of Gamma Knife devices using an elliptical dose model. It is shown that volume averaging increases with the increase in the detector’s sensitive volume. Therefore, the Semiflex ionization chamber had the largest correction factor for all field sizes and the RAZORnano chamber had the smallest. For all studied detectors volume averaging decreased with an increase in field size.

Eunicella cavolini (Koch, 1887) generally recognized as yellow gorgonian, is a species of colonial soft coral in the family Gorgoniidae. Although it is common in the Mediterranean basin, the evaluation of biological potential of E. cavolini from the Adriatic Sea has not been performed yet. Taking this into account, as a part of our Center of excellence for Marine Bioprospecting of Adriatic Sea BioProCro, we have studied the chemical composition and biological activities of this gorgonian. [1] In this contribution, we will discuss the results of screenings of the antiproliferative, antibacterial, antioxidant, and anti-inflammatory activities of organic extracts and corresponding semipurified fractions. Additionally, we will show data concerning antiproliferative activity against four cancer cell lines and one non-transformed cell line, as well as its anti-inflammatory potential concerning the successfully isolated pregnane type steroid by employing dereplication methods. In final, we will present the synthesis of granulatamide B [2] isolated from the coral species of the Eunicella genus and its 12 derivatives by employing Fürstner’s Fe-catalyzed C–C coupling reaction. [3] The obtained small compound library of these N-acyl tryptamines differing in the number of C-atoms, saturation degree and conjugation of double bonds, were evaluated towards the formation and development of zebrafish Danio rerio embryos. [4]

Marine macroalgae or seaweeds are in a continuous focus of the scientific community, but even in the focus of a wider public as they are acknowledged as a valuable source of different bioactive compounds such as polyphenols, peptides, pigments, and polysaccharides that are associated with several health benefits and biological activities. Brown algae are known for their accumulation of specific metabolites with great antioxidant potential. In this study, we evaluated the antioxidant activity of different fractions from two brown macroalgae, Dichtyota dichotoma, and Dichtyota fasciola. The primarily used method was square-wave voltammetry (SWV), followed by the reduction of the radical cation (ABTS), the 2, 2-diphenyl-1-picryl-hydrazyl (DPPH) assay, the Folin–Ciocalteu, and the oxygen radical absorbance capacity (ORAC) assays. To correlate obtained results for antioxidant activity, Pearson’s correlation coefficient was used. Toxicity evaluation of obtained fractions revealed the safety of their usage and further implementation. In this research, the dry residues of extracts from brown macroalgae samples were immobilized on the surface of GCE and immersed into a 0.1 mol/L phosphate buffer solution. To evaluate their activity and optimal electrochemical response, a change in the pH values, ranging from 3 to 11, for all obtained extracts was tested. To assess antioxidant activity using voltammetric analysis, the area under the curve (AUC) was integrated, the value of which represents an estimate of the total antioxidant activity of the extracts. The highest antioxidant activity based on the AUC value was obtained for D. fasciola F2 (0.099±0.001 mg/g GAE) followed by D. fasciola F3 (0.068±0.006 mg/g GAE) > D. dichotoma F3 (0.050±0.002 mg/g GAE) > D. dichotoma F2 (0.028±0.002mg/g GAE). No significant difference in antioxidant activity was observed between fractions of two Dictyota species. Other employed spectrophotometric methods also revealed similar behavior of two Dictyota species, however, somewhat higher activity was observed for both D. dichotoma fractions. The Pearson’s correlation coefficient for SWV versus Folin-Ciocalteu method was a negative value of -0.99 (p

Marine natural alkaloid, granulatamide B, belonging to the class of N-fatty acyl tryptamines, have been isolated from the coral species of the Eunicella genus.1 Despite the known moderate activity against various cancer cell lines in vitro, little is known about its other biological activities. Therefore, within our project, Bioprospecting of the Adriatic Sea, we have synthesized granulatamide B according to the procedure of Fürstner’s Fe-catalysed synthesis2, accompanied with several structural analogues formed by modification of the acyl moiety. A small compound library has been designed, containing a total of 13 compounds differing in the number of C-atoms, saturation degree and conjugation of double bonds. The aim of this study was to evaluate the effects of the synthesized compounds towards the formation and development of zebra fish Danio rerio embryos following previously described protocol.3 Among tested compounds in our study, 4 out of 13 harmed the survival and embryonic development of D. rerio within the tested concentration range. The highest toxicity in terms of zebrafish mortality was observed for compounds containing fatty acyl chains with conjugated double bonds including granulatamide B (LC50=44.34 µM). In addition, the most common developmental abnormalities observed during exposure to above mentioned compounds were edemas, scoliosis and blood accumulation.

Marine macroalgae are an extremely valuable source of bioactive molecules with unique properties and multiple potential applications in the cosmeceutical, pharmaceutical, and food industries. Adriatic Sea is an extremely harsh environment characterized by high salinity, seasonal oscillations in temperature and relatively shallow depth which indicates increased UV radiation. It can be assumed that such conditions have forced macroalgae to evolutionary develop molecules which could through activation of anti-stress mechanisms enable surviving in such a hostile environment. With such a hypothesis, Codium adhaerens was sampled from the Adriatic Sea, extracted with methanol:dichloromethane and further fractionated by solid phase extraction to obtain less polar fractions (F3, F4). Chemical composition was determined by UHPLC-ESIHRMS and the antioxidant potential was comprehensively evaluated using colorimetric assays (Folin- Ciocalteu, ABTS, DPPH, FRAP) and in vivo experiments on zebrafish Danio rerio. Zebrafish D. rerio embryos were employed for this research, as currently one of the most valuable laboratory model organisms for bioactivity determination of natural and synthetic molecules. The results obtained from in vivo experiments on zebrafish embryos demonstrated protective effects of tested C. adhaerens fractions against H2O2 induced mortality (23% and 27% declined mortality in 500 μg/mL of F3 and F4 fractions), along with the significant decrease of reactive oxygen species (ROS) generation. F3 and F4 in concentration of 500 μg/mL significantly decreased (p

The process of environmental pollution is experiencing exponential and unstoppable growth and has become one of the biggest problems facing humanity today. Progress in science has also brought a new type of pollution, therapeutic drugs, or pharmaceutically active compounds that are one of the main components of inland water pollution and that have been found in the sediment and plasma of fish from the Sava River. Based on previous research, cardiovascular drugs have been chosen: amiodarone, ramipril, simvastatin and verapamil, the effect of which has been investigated, individually and in a mixture, on the development of the zebrafish embryo Danio rerio (Hamilton, 1822) in the first 96 hpf. During exposure to environmentally relevant concentrations (0.1, 1.0 and 10.0 μg/L), caused changes such as mortality and abnormality rate, larval length, hatching rate, heart rate, spontaneous movements of the pectoral fins and oxidative stress were monitored. With increasing concentration and time exposure of individuals to the tested compounds, effects on exposure to all compounds were observed, but the highest toxicity was observed on the simvastatin sample. The integration of the ultimate biological effects examined within this study confirmed the excellent cause-and-effect relationship between exposure to pharmaceutical compounds and the observed effect on the aquatic organism, thus providing a basis for biomonitoring of environmental pollution, especially freshwater ecosystems.

Purpose: In recent years, the use of small and nonstandard photon fields in radiation therapy has increased exponentially. Volume averaging of a measured signal is a known problem in small photon beam dosimetry which affects the reading of detectors and artificially widens the penumbra region of a measured dose profile and may result in an underestimation of the absorbed dose to water on the beam central axis. Volume averaging becomes more pronounced by reducing the radiation field size. To account for this, the measured value has to be corrected with the volume averaging correction factor. For conventional LINACs, Cyber Knifes, and Tomotherapy units, volume averaging correction is calculated using Kawachi formalism [1]. However, due to the different radiation field geometry, this formalism must be modified from 2D to 3D calculations to apply to Gamma Knife (Elekta, Stockholm, Sweden). This work aimed to determine the volume averaging correction factors at the isocenter for different detectors and field sizes in narrow Co-60 beams used by Gamma Knife. Methods and Materials: Detectors that were studied are: Semiflex TM31010 (PTW, Freiburg, Germany), PinPoint TM31014 (PTW, Freiburg, Germany), Dosimetry Diode P TM60016 and E TM60017 (PTW, Freiburg, Germany) and microDiamond TM60019 (PTW, Freiburg, Germany). To determine a volume averaging correction for different detectors a 3D elliptical dose model for Gamma Knife Icon is used [2]. Normalized dose profiles calculated using the Pegasos system [3] which is based on Monte Carlo code Penelope and provided by Elekta (Sweden) were fitted to a sum of error functions using CurveExpert Professional software (Hymas Development, USA). Using fitted dose profiles and an elliptical 3D dose model, an analytical expression and visualization of different field sizes were obtained using MATLAB (TheMathWorks Inc., USA). To determine the volume averaging correction factor for a given detector, a simulation of its geometry inside the field is necessary. Using numerical integration (Simpson's rule) we were able to determine the volume averaging correction factor for studied detectors in different field sizes. Results: Semiflex chamber (V=125 mm3) has the largest volume averaging correction factor due to its volume ; 1.009, 1.283, 1.787 for 16, 8, and 4 mm field sizes respectively. Second in size is the PinPoint chamber (V=15.71 mm3) with corrections of 1.007, 1.023, and 1.291 for 16, 8, and 4 mm field sizes respectively. Dosimetry Diode P and E (V=0.03 mm3) have the same correction since their sensitive volume is the same size and the only difference is in active volume shielding which does not affect the volume averaging correction. Volume averaging results for diodes are 1.006 for a 4 mm field, 1.001 for 8 mm, and 1.000 for a 16 mm field size. Finally, results for the microDiamond (V=3.8∙10-3 mm3) are 1.000, 1.004, and 1.020 for 16, 8, and 4 mm field sizes respectively. Conclusion: This work has illustrated the possibility to determine volume averaging correction factors on Gamma Knife using an elliptical dose model. It is shown, as expected, that volume averaging increases with the increase in detectors size i.e. detectors sensitive volume. In general, the Semiflex chamber had the biggest correction for all field sizes followed by a PinPoin chamber, microDiamond, and Diode P and E. For all studied detectors volume averaging correction decreased with the increase in the field size.

Bioactive potential of brown alga Padina pavonica from the Adriatic Sea was described according to the tests conducted.

Razvojem tehnologije i povećanom željom za učenjem i smanjivanjem fizički napornih poslova u proizvodnim pogonima i svakodnevici pojavljuje se želja za uvođenjem automatiziranih i robotskih sustava u proizvodnji. Brojni automatizirani sustavi zahtijevaju vrlo brze odzive na pojave ulaznih signala, što je puno jednostavnije izvesti pomoću PLC kontrolera nego sa zastarjelim složenim sustavima pomoću upravljanja relejima. Projektiranje ovog automatiziranog sustava uključuje odabir dijelova, korištenje različitih postupaka obrade materijala, spajanje različitih vrsta shema, projektiranje izgleda, pisanje i simuliranje programskog koda u „CyPro“ i „RoboCel“ programskim jezicima te rješavanje problematike kretanja i sortiranja određenih dijelova. U praksi se učestalo nalaze primjeri automatizacije starih sustava čiji su projekti financijski ograničeni. Za kvalitetan sustav koji će raditi bez problema potrebno je pronaći idealno ali i jednostavno tehničko rješenje koje će omogućiti nesmetan rad sustava. Tako i u ovome slučaju gdje se radi o dvije potpuno različite platforme „Cybro“ PLC sustava i „Intelitek“ robotske ruke Scorbase er 4u koja se temelji na Siemensovoj tehnologiji objedinjene su u funkcionalnu cjelinu u svrhu paletiziranja.

Due to the increasing human population and the negative impact of fossil fuel combustion on the environment, there is an ever-increasing need for sustainable energy development [1]. Since microalgae offer several advantages (high growth rate, high oil content, etc), they have been considered a promising candidate for alternative renewable fuel sources (biodiesel, bioethanol, etc.). The two most important factors affecting biodiesel production, oil content, and microalgal fatty acids profile, are highly dependent upon the used microalgae species and cultivation conditions. Furthermore, studies have confirmed the beneficial effect of trace elements (Co, Cr, Mn, Mo, Cu, Fe, Zn) on microalgal growth and lipid content [2]. This research aimed to assess the dependence of total fatty acids content and profile in marine microalgae Dunaliella tertiolecta upon exposure to different concentrations of sodium selenite (Se) during two-stage cultivation. Total lipids were determined as total fatty acid methyl esters (FAME) by in-situ transesterification, while the FAME content was determined using gas chromatography [3]. According to the obtained results, the total FAME content of the control treatment group (no Se addition) was approximately 2-fold higher compared to the 20.00, 40.00 and 80.00 mg L-1 selenite treatment groups, which can be explained by the excessive exposure time of microalgae cells to Se which leads to a decrease in lipid synthesis. Furthermore, it was reported that in the control medium, γ-linoleic acid (C18:3 (c6, c9, c12) and palmitic acid (C16:0) were present in a higher proportion. Increasing the Se concentration in the culture medium increases the proportion of C16:0, while the proportion of C18:3 (c6, c9, c12) decreases, which indicates that the addition of Se in a culture medium, as a stress factor, contributes to the synthesis of monounsaturated fatty acids (MUFA). Since highly saturated fatty acids (e.g. C16:0) contribute to the satisfactory value of cetane number and oxidative stability parameters, which represent important biodiesel standards, it can be concluded that the present study reports valuable data regarding the influence of Se on fatty acids content and profile in microalgae D. tertiolecta and therefore potentially sustainable biodiesel production.

Brown macroalgae have recently been in the focus of many researches due to their composition and the accumulation of specific metabolites with great antioxidant potential. Food, cosmetics, and pharmaceutical industries are constantly working to find natural, non-toxic compounds that can be used in their products. In this study, we evaluated the antioxidant activity of two (methanolic and dichloromethane) different fractions from three brown macroalgae, Dichtyota dichotoma, Dichtyota fasciola, and Halopteris scoparia. Several methods were used for the evaluation of antioxidant activity including the reduction of the radical cation (ABTS), the 2, 2-diphenyl-1-picryl-hydrazyl (DPPH), the Folin–Ciocalteu, and the oxygen radical absorbance capacity (ORAC) assays. Also, total protein content was determined by the Lowry method with slight modifications, while chlorophyll and carotenoid content were determined spectrophotometrically by the Lichtenthaler method. The toxicity of samples was determined using the zebrafish embryotoxicity test up to 96 h of embryonal development. All methanolic fractions showed higher antioxidant activity than the dichloromethane fractions, while H. scoparia methanolic fraction showed the highest activity (IC50 concentration of 1.947 mg/mL). The highest protein value was observed for Halopteris scoparia (20.7%) followed by Dichtyota dichotoma (7.4%) and Dichtyota fasciola (3.3%). Because of their good antioxidant potential, all three researched brown macroalgae have the potential to be used as a source of natural antioxidants in the cosmetic industry.

Microalgae and bacteria are part of the vital components of various ecosystems. Photosynthetic microalgae capture solar energy and convert it to bioenergy and biochemical products. They exude dissolved organic carbon that becomes available to bacteria. In return, the bacteria remineralize sulphur, nitrogen and phosphorous to support the further growth of microalgae. Microalgae-bacteria symbiosis represents commensal and mutualistic inter-kingdom relationships, that may result in stimulation of algal growth, but also in the development of new metabolites with a prominent potential for application in the industry sector. Chlorella vulgaris is a green unicellular microalga with numerous biological and pharmacological properties important for human health. Streptomycetes are the most thoroughly studied microorganisms producing biologically active compounds, such as antibiotics, anticancer agents, immunosuppressives, antifungals, etc. In the recent decade, co-cultivation, as a potential replacement for monoculturures of various microorganisms, gained special interest due to a whole range of desirable characteristics, such as modularity, robustness, predictability, scalability and stability. However, very little is known about the significance of S. rimosus and C. vulgaris co-cultures concerning the production of high-value metabolites with anti-bacterial, anti- oxidant, and anti-aging activities. To determine the significance of their co-cultivation, a rangeseries of biological assays were performed on algal and bacterial monocultures, as well as co- culture. The antimicrobial activity of extracts against Gram-positive and -negative bacteria was tested using the microdilution broth method. Extracts from single cultures had dose-dependent inhibitor activity against tested microorganisms, while co-culture extracts showed higher activity compared to extracts from monocultures. Furthermore, the antioxidant activity was investigated by 4 spectrophotometric methods. The highest antioxidant activity was obtained using the ferric reducing antioxidant power assay on algal monoculture and co-cultivation. In terms of anti-aging properties, inhibition of collagenase activity was recorded on S. rimosus monoculture and co-culture. Tested extracts showed no negative impact on the survival/development of zebrafish Danio rerio embryos, which taken together with other results implies their potential for broadening their biotechnological applications.

Brown macroalgae or seaweeds have recently been in the focus of many researchers due to their composition and the accumulation of specific metabolites with great antioxidant potential. They represent a valuable source of bioactive compounds: polyphenols, pigments, peptides and polysaccharides that are associated with several health benefits and biological activities. Food, cosmetics and pharmaceutical industries are constantly working to find natural, non-toxic compounds that can be used in their products. In this study, we evaluated the antioxidant activity of two (methanolic F3 and dichlormethane F4) different fractions from macroalga Halopteris scoparia in order to determine differences between harvesting season. Total protein content, chlorophyll and carotenoid content were determined. Also, several methods were used for evaluation of antioxidant activity. The semipurified fractions were also tested for antimicrobial activity using broth microdilution method for quantitative assessment and the toxicity of samples was determined using the zebrafish embryotoxicity test up to 96 h of embryonal development in order to reveal the safety of their usage and further implementation. Pearson’s correlation coefficient was used to correlate obtained results for antioxidant activity. All methanolic fractions showed higher antioxidant activity than the dichloromethane fractions of the same season by implementing 3 different antioxidants assays, namely reduction of the radical cation (ABTS), the 2, 2-diphenyl-1 picrylhydrazyl (DPPH) and the oxygen radical absorbance capacity (ORAC) assays. April sample of H. scoparia (HASC) methanolic fraction (F3) showed the highest activity (268.6±20.6 mg AAE/g fraction) followed by HASC F4 April and HASC F3 February samples by DPPH method (Fig.1a). By using ABTS assay, the highest activity was observed for HASC F3 February followed by F3 April and F3 July fractions. The highest protein value was observed for Halopteris scoparia April sample (20.5%) followed by HASC July (19.7%) and February (14.3%) samples. Chloropyll a and its derivate pheophytin a are dominant pigments in all three samples and the highest pigment content (chloropyll a and b, pheophytine a and b and carotenoids) was observed for HASC February sample. Obtained results indicate that harvesting season has a crutial role in obtaining samples with the best properties that have a potential to be used as a source of natural antioxidants in the food, pharmaceutical and cosmetic industry.

Biomedicinsko istraživanje reprodukcije i razvoja (BIRRD) uključuje više od 70 znanstvenika raspoređenih u tzv. projektne elemente znanstvenoistraživačkog projekta Reproduktivna i regenerativna medicina – istraživanja novih platformi i potencijala (EU KK.01.1.1.01.0008). Elementi projekta doprinose: 1. podizanju razine kohezije projektnog tima i infrastrukture na razinu priznatih laboratorija u EU ; 2. poticanju integracije u glavne nacionalne i međunarodne mreže ; 3. podizanju kompetentnosti i konkurentnosti tima ; 4. provođenju visokovrijednih znanstvenih istraživanja i promicanju izvrsnosti u znanosti te podizanju svijesti o reproduktivnom zdravlju. Istraživačka jedinica Biomedicinsko istraživanje reprodukcije i razvoja povezuje bazična istraživanja reprodukcije i razvoja na sisavcima (koja se provode na životinjskim modelima in vivo i in vitro) te kliničke studije o neplodnosti muškarca, tumorima sjemenika, patološkim trudnoćama, kongenitalnim anomalijama i genetskim poremećajima. Ove aktivnosti omogućuju translaciju temeljnih istraživanja u kliniku i obrnuto.

Proces onečišćenja okoliša doživljava eksponencijalan i nezaustavljiv rast te je postao jedan od najvećih problema s kojima se danas čovječanstvo susreće. Napredak znanosti doveo je i novu vrstu onečišćenja, lijekovima, odnosno farmaceutski aktivnim spojevima koji su jedna od glavnih komponenti onečišćenja kopnenih voda i koji su utvrđeni u sedimentu i plazmi riba iz rijeke Save [1, 2]. Na temelju dosadašnjih istraživanja izdvojeni su kardiovaskularni lijekovi: amiodaron, ramipril, simvastatin i verapamil čiji je utjecaj istražen, pojedinačno i u smjesi, na razvoj embrija ribe zebrice Danio rerio (Hamilton, 1822) u prvih 96 hpf. Tijekom izlaganja okolišno relevantnim koncentracijama (0, 1, 1, 0 i 10, 0 µg/L) praćene su izazvane promjene kao što su mortalitet i stopa abnormalnosti, dužina ličinki, stopa izvaljivanja, brzina otkucaja srca, spontani pokreti prsnim perajama i oksidativni stres. Povećanjem koncentracije i vremenske izloženosti jedinki testiranim spojevima uočeni su učinci pri izlaganju svim spojevima, no najveća toksičnost zabilježena je na uzorku simvastatina. Integracijom krajnjih bioloških učinaka ispitivanih unutar ovog istraživanja, potvrđena je izvrsna uzročno-posljedična veza između izlaganja farmaceutskim spojevima i zabilježenog učinka na akvatičkom organizmu, čime je pružena podloga za biomonitoring onečišćenja okoliša, posebice slatkovodnih ekosustava.

Aim: After removing dental restorative materials, their dust goes into the wastewater, and enters the aquatic ecosystems. Previous studies based on the study of (eco)toxic potential of dental materials were mostly based on cell lines while neglecting the effects on model vertebrate organisms. For this reason, this research aims to determine the influence of microparticles of composite materials and their eluates on the embryonic development of the zebrafish Danio rerio. Materials and methods: This study included two types of composite materials: commercial composite (Tetric EvoCeram, Ivoclar Vivadent) and laboratory composite (30% BisGMA/TEGDMA 60:40, 70% filler). Composite samples (d=6mm, h=2mm) were polymerized with Bluephase G2 (Ivoclar Vivadent ; 1200mW/cm2) for 10s. The samples were then ground, their powder collected, and dispersed in zebrafish medium. Samples were incubated on a shaker for 48h and 7 days, after which an embryotoxicity test was performed on Danio rerio embryos. In addition to mortality rates and morphological abnormalities, the cardiotoxic and neurotoxic potential was monitored. The chemical composition of the eluates was determined by high-performance liquid chromatography (Agilent 1260 Bioinert) to identify released monomers. Results: Only UDMA at a concentration of 1.21mg/ml was detected in the 48h-eluates of Tetric EvoCeram, which was present at a reduced concentration of 0.69mg/mL in 7d- eluates. TEGDMA (0.016mg/mL) was detected in the laboratory composite after 48h, with the same concentration after 7 days. Composite microparticles showed a negative effect on the embryonic development of zebrafish depending on the tested concentration. The most commonly observed developmental abnormalities during exposure were pericardial edema and scoliosis. Both tested composites caused increased heart activity. The reduction of the individuals length, the lack of pigmentation, and the accelerated pectoral fin movement were more pronounced in the commercial composite. Conclusion: The embryotoxicity of the tested eluates of dental composites was largest after 48h of incubation in the medium. The obtained results highlight the potentially negative impact on aquatic ecosystems and emphasize the importance of timely removal and disposal of these materials.

Norma ISO 21001:2018 Obrazovne organizacije — Sustavi upravljanja obrazovnim organizacijama — Zahtjevi sa smjernicama za uporabu doživjela je svoje prvo izdanje relativno nedavno, u svibnju 2018. godine. Kao što je vidljivo iz naslova, norma sadrži zahtjeve za sustav upravljanja u obrazovnim organizacijama različitih tipova i veličina te, što je važno naglasiti, neovisno o tome pruža li organizacija obrazovne usluge u sektoru cjeloživotnog, visokog, srednjeg, osnovnog ili pak predškolskog obrazovanja. U radu će biti opisana povijest nastanka ove norme, njena osnovna struktura (HLS), usporedba sa zahtjevima norme ISO 9001:2015 s naglaskom na sličnosti i razlike zahtjeva ove dvije norme, te veliki potencijal primjene sustava upravljanja obrazovnom organizacijom (engl. EOMS) prema zahtjevima ISO 21001:2018. Pri tome nije važno dolazi li organizacija iz privatnog ili javnog sektora te pruža li usluge formalnog i/ili neformalnog obrazovanja. Također, norma ISO 21001:2018 donosi i neke novine u odnosu na norme koje sadrže zahtjeve za ostale sustave upravljanja. Jedna od tih novina odnosi se na relativno veliki broj dodataka, kojih u ovoj normi ima čak sedam. Jedan od njih je normativni (Dodatak A), a ostalih šest su informativni i sadrže prilično detaljno opisane smjernice za korištenje EOMS. Detaljnije će biti opisan informativni Dodatak B koji navodi 11 načela EOMS, ističe njihove ključne prednosti za organizaciju i navodi moguće aktivnosti u organizaciji u skladu s pojedinim načelom.

Prošle godine je skoro 7000 maturanata pristupilo ispitu državne mature iz fizike, a više od 1000 kandidata prijemnom ispitu za studij medicine u Zagrebu. Ispit državne mature iz fizike s 36 pitanja piše 3 sata uz dozvoljene formule, a prijemni ispit za medicinu s ukupno 120 pitanja iz biologije, kemije i fizike isto tako dugo bez dodatne pomoći formula. Cilj našeg istraživanja je usporediti postignute rezultate kandidata na oba ispita. Predstavit ćemo nekoliko zadataka s višestrukim odgovorima iz različitih područja fizike i diskutirati dobivene rezultate. Zadaci s višestrukim odgovorima na maturi imaju 3 ili 4, a na prijemnom ispitu 5 ponuđenih odgovora.