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Povzetek: Research activities on lead-free piezoelectric ceramic materials have been ongoing for over twenty years. In the meantime, many of the initial drawbacks of these materials compared to conventional lead titanate-zirconate (PZT) ceramics have been overcome. Today, industrial production of potassium-sodium niobate (KNN)-based ceramics has become a reality, applications have been identified and KNN-based products have been manufactured. While certain KNN compositions have achieved piezoelectric performance comparable to, or even exceeding, that of lead-based systems, persistent inconsistencies in the literature regarding the description of their crystalline structures underscore the need for a clearer understanding. This focused review critically examines the key factors shaping the crystal structure of KNN ceramics, with a particular emphasis on processing techniques as a pivotal parameter. The discussion is organized around three fundamental aspects: i) the crystal structure of pure KNN, ii) the structural modifications induced by additives, and iii) the influence of texturing processes on crystalline organization. Special attention is devoted to X-ray diffraction (XRD) characterization and the structure-property relationships that govern KNN’s performance.
Ključne besede: piezoelectrics, lead-free, potassium sodium niobate, processing, crystal structure
Objavljeno v DiRROS: 04.09.2026; Ogledov: 42; Prenosov: 27
Celotno besedilo (9,35 MB)
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Povzetek: This study investigated the bioaccessibility of ten synthetic lutein diesters using the in vitro INFOGEST human digestion model, enabling comparative evaluation of their digestive behavior under controlled food-matrix conditions. We revealed that lutein ester chain length was the primary determinant of bioaccessibility, while branching influenced the extent of hydrolysis. Linear short-chain diesters demonstrated superior bioaccessibility (6.7–18.9%). Branched and bulky derivatives, surprisingly, achieved comparable bioaccessibility (6.6–8.3%) despite high hydrolytic resistance, suggesting mechanisms beyond simple ester cleavage. Conversely, long-chain lutein diesters (> C10), prevalent in commercial supplements, exhibited poor micellization, limited hydrolysis, and consequently very low bioaccessibility (<3%). Finally, two pharmaceutical formulations of the lead lutein diester, lutein di(2,2-dimethylpropanoate), were developed: a sunflower oil formulation and a liquisolid formulation utilizing a porous aluminometasilicate carrier. The sunflower oil formulation enabled significantly higher pigment stability and bioaccessibility, highlighting its superior potential for effective lutein delivery in novel food and pharmaceutical applications.
Ključne besede: lutein diesters, INFOGEST in vitro digestion, bioaccessibility, hydrolysis efficiency, chemical structure, structure-property relationship
Objavljeno v DiRROS: 02.09.2026; Ogledov: 75; Prenosov: 45
Celotno besedilo (1,19 MB)
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Povzetek: This study aims to determine whether and to what extent the structure and composition of thrombi can be assessed using NMR and CT measurements. Seven different thrombus models, namely, six RBC thrombi with hematocrit levels (HTs) of 0%, 20%, 40%, 60%, 80% and 100% and one platelet thrombus model, were analyzed using proton NMR at 100 MHz and 400 MHz, with measurements of T1 and T2 NMR relaxation times and measurements of the apparent diffusion coefficient (ADC). In addition, the thrombus models were CT-scanned in a dual-energy mode (80 kV and 140 kV) and in a single-energy mode (80 kV) to measure their CT numbers. The results confirmed that RBC thrombi can be distinguished from platelet thrombi by using ADC and CT number measurements in all three settings, while they cannot be distinguished by using T1 and T2 measurements. All measured parameters allowed for the differentiation of RBC thrombi according to their HT values, but the best sensitivity to HT was obtained with ADC and single-energy CT measurements. The importance of this study also lies in the potential application of its results for the characterization of actual thrombi in vivo.
Ključne besede: artifical blood clots, thrombosis, Hounsfield units, NMR relaxation, apparent diffusion coefficient, structure, composition
Objavljeno v DiRROS: 27.08.2026; Ogledov: 96; Prenosov: 51
Celotno besedilo (1,89 MB)
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Povzetek: The clam Polititapes aureus is one of the most abundant shellfish species in southern Tunisian waters. Its potential future commercial value is key resource for artisanal fisheries. This study was conducted to assess stocks and develop a management plan for natural clam populations along the Sfax coast. The results revealed significant density fluctuations across the study area, which was divided into six main sites, with stock density ranging from 0 to 6 ind.m⁻² and biomass values varying between 0 and 41 g.m⁻². Total biomass reached 70.1 tons, with an abundance exceeding 16.58 million individuals across 3,867 hectares. Sampled individuals measured between 3 and 32.9 mm in size. Key environmental factors were identified, with several abiotic parameters found to have a significant impact on the distribution of clam species. Conservation guidelines are proposed to restore its stocks to sustainable levels
Ključne besede: bivalve, Polititapes aureus, stock assessment, distribution, size structure, South Tunisia
Objavljeno v DiRROS: 28.06.2026; Ogledov: 255; Prenosov: 161
Celotno besedilo (1,61 MB)
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Ključne besede: cytoplasmic variation, germplasm characterization, phenotypic diversity, plant breeding, population structure, selection Index
Objavljeno v DiRROS: 04.06.2026; Ogledov: 312; Prenosov: 246
Celotno besedilo (2,61 MB)
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