1721. Phytoplankton assemblage over a 14-year period in the Adriatic Sea : patterns and trendsSanda Skejić, Blanka Milić Roje, Frano Matić, Jasna Arapov, Janja Francé, Mia Bužančić, Ana Bakrač, Maja Straka, Živana Ninčević Gladan, 2024, original scientific article Abstract: Considering the role of phytoplankton in the functioning and health of marine systems, it is important to characterize its responses to a changing environment. The central Adriatic Sea, as a generally oligotrophic area, is a suitable environment to distinguish between regular fluctuations in phytoplankton and those caused by anthropogenic or climatic influences. This study provides a long-term perspective of phytoplankton assemblage in the central eastern Adriatic Sea, with 14 years of continuous time series data collected at two coastal and two offshore stations. The predominant phytoplankton groups were diatoms and phytoflagellates, but their proportion varied depending on the vicinity of the coast, as evidenced also by the distribution of chlorophyll a. In the coastal environment, the phytoplankton biomass was substantially higher, with a higher proportion of microphytoplankton, while small phytoplankton accounted for the majority of biomass in the offshore area. In addition, a decreasing trend in diatom abundance was observed in the coastal waters, while such trend was not so evident in the offshore area. Using a neural gas algorithm, five clusters were defined based on the contribution of the major groups. The observed increase in diversity, especially in dinoflagellates, which outnumber diatom taxa, could be a possible adaptation of dinoflagellates to the increased natural solar radiation in summer and the increased sea surface temperature.
Keywords: phytoplankton community, long-term data, diversity, chlorophyll a, neural gas analysis, solar radiation, Adriatic Sea
Published in DiRROS: 11.07.2024; Views: 359; Downloads: 261
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1723. Oral bioaccessibility of potentially toxic elements in various environmental mediaMartin Gaberšek, Mateja Gosar, 2024, original scientific article Abstract: An important aspect of geochemical studies is determining health hazard of potentially toxic elements (PTEs). Key information on PTEs behaviour in the human body in case of their ingestion is provided with the use of in vitro bioaccessibility tests. We analysed and compared oral bioaccessibility of a wide range of PTEs (As, Cd, Ce, Cr, Cu, Hg, La, Li, Ni, Pb, Sb, Sn, Zn), including some that are not often studied but might pose a human health hazard, in soil, attic dust, street dust, and household dust, using Unified BARGE Method (UBM). Additionally, feasibility of usage of scanning electron microscope techniques in analyses of solid residuals of UBM phases was tested. Results show that bioaccessible fractions (BAFs) of PTEs vary significantly between individual samples of the same medium, between different media and between the gastric and gastro-intestinal phases. In soil, attic dust and street dust, bioaccessibility of individual PTE is mostly higher in gastric than in gastro-intestinal phase. The opposite is true for PTEs in household dust. In all four media, with the exception of Pb in household dust, among the most bioaccessible PTEs in gastric phase are Cd, Cu, Pb, and Zn. During the transition from the stomach to small intestine, the mean BAFs of most elements in soil, attic dust, and street dust decreases. The most bioaccessible PTEs in gastro-intestinal phase are Cu, Cd, Ni, and As. Micromorphological and chemical characterisation at individual particle level before and after bioaccessibility test contribute significantly to the understanding of oral bioaccessibility.
Keywords: urban geochemistry, UBM, soil, attic dust, street dust, household dust
Published in DiRROS: 10.07.2024; Views: 391; Downloads: 143
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1724. Synergetic boost of functional properties near critical end points in antiferroelectric systemsVida Jurečič, Lovro Fulanović, Jurij Koruza, Vid Bobnar, Nikola Novak, 2023, original scientific article Abstract: The increase of the dielectric permittivity with an electric field and enhanced energy storage properties make antiferroelectrics very attractive for high-power electronic applications needed in emerging green energy technologies and neuromorphic computing platforms. Their exceptional functional properties are closely related to the electric field-induced antiferroelectric↔ferroelectric phase transition, which can be driven toward a critical end point by manipulation with an external electric field. The critical fluctuation of physical properties at the critical end point in ferroelectrics is a promising approach to improve their functional properties. Here, we demonstrate the existence of two critical end points in antiferroelectric ceramics with a ferroelectric-antiferroelectric-paraelectric phase sequence, using the model system Pb 0.99 Nb 0.02 [ ( Zr 0.57 Sn 0.43 ) 0.92 Ti 0.08 ] 0.98 O 3 . The critical fluctuation of the dielectric permittivity in the proximity of the antiferroelectric-to-paraelectric critical end point is responsible for the strong enhancement of the dielectric tunability (by a factor of > 2 ) measured at ≈ 395 K. The enhancement of the energy storage density at ≈ 370 K is related to the proximity of the ferroelectric-to-antiferroelectric critical end point. These findings open possibilities for material design and pave the way for the next generation of high-energy storage materials.
Keywords: electronic applications, high-power electronic, green energy, electric field
Published in DiRROS: 10.07.2024; Views: 367; Downloads: 216
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1727. Advances in the management of craniopharyngioma in children and adultsMojca Jensterle Sever, Sončka Jazbinšek, Roman Bošnjak, Mara Popović, Lorna Zadravec-Zaletel, Tina Vipotnik-Vesnaver, Barbara Faganel Kotnik, Primož Kotnik, 2019, review article Abstract: Childhood and adult-onset craniopharyngioma is a rare embryogenic tumor of the sellar, suprasellar, and parasellar region. Survival rates are high; however, tumor location and treatment sequalae including endocrine deficits, visual impairment, metabolic complications, cognitive and psychosocial deficits can significantly impair patient%s quality of life. There is considerable controversy regarding the optimal management of craniopharyngiomas. Subtotal resection of the tumor followed by targeted irradiation to avoid further hypothalamic damage is currently indicated. Novel insights in the tumor%s molecular pathology present the possibility for targeted therapy possibly decreasing the rate and severity of treatment-associated morbidity. Conclusions. Craniopharyngioma should be seen as a chronic disease. To achieve optimal outcomes a multidisciplinary team of specialized neurosurgeons, neuro-radiologists, neuro-oncologists, pathologists and endocrinologists should be involved in the diagnosis, planning of the surgery, irradiation and long-term follow-up.
Keywords: craniopharyngioma, hypopituitarism, metabolic syndrome
Published in DiRROS: 09.07.2024; Views: 377; Downloads: 191
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1728. Diagnostic accuracy of haemophilia early arthropathy detection with ultrasound (HEAD-US) : a comparative magnetic resonance imaging (MRI) studyDomen Plut, Barbara Faganel Kotnik, Irena Preložnik Zupan, Damjana Ključevšek, Gaj Vidmar, Žiga Snoj, Carlo Martinoli, Vladka Salapura, 2019, original scientific article Keywords: haemophilia, haemophilic arthropathy, magnetic resonance imaging
Published in DiRROS: 09.07.2024; Views: 347; Downloads: 132
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