1. Combining ToF-SIMS and multivariate analysis to resolve active sites on Ni-based HER catalystsMatjaž Finšgar, Katja Andrina Varda, Dževad Kozlica, Matej Huš, Milena Martins, Dušan Strmčnik, 2026, original scientific article Abstract: Unambiguous identification of active sites in heterogeneous catalysis remains a major challenge, particularly formaterials with ultrathin, chemically mixed surface layers. Here, we demonstrate a generalizable approach that combinestime-of-flight secondary ion mass spectrometry (ToF-SIMS) with multivariate statistical analysis (principal componentanalysis [PCA] and multivariate curve resolution [MCR]) to resolve catalytically relevant motifs at the nanoscale. Using Nielectrodes as a model system, PCA distinguished hydroxide-enriched domains from oxide- and metal-rich regions, whileMCR decomposed depth profiles and 3D images into hydroxide, oxide, and metallic layers with nanometer resolution.A unique secondary-ion fragment, NiO3 H 3− (m/z 108.94), emerged as a marker of hydroxide-rich environments andcorrelated with hydrogen evolution reaction (HER) activity across a series of Ni electrodes. Complementary densityfunctional theory (DFT) calculations revealed that Ni(OH)2 clusters adjacent to metallic Ni offer the most favorable waterdissociation energetics, establishing the structural origin of the marker. While illustrated here for Ni-based HER, thisworkflow provides a broadly applicable framework to isolate and rank near-surface patterns that govern catalytic activity,thereby extending ToF-SIMS from a qualitative probe to a predictive tool for active site identification. Keywords: HER active sites, multivariate statistical analysis, nickel catalysts, ToF-SIMS Published in DiRROS: 08.07.2026; Views: 276; Downloads: 326
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2. Uncovering phenotypic variation in common bean (Phaseolus vulgaris L.) : insights from the INCREASE projectHourieh Tavakoli Hasanaklou, Lovro Sinkovič, Roberto Papa, Elena Bitocchi, Elisa Bellucci, Peter Dolničar, Barbara Pipan, 2026, original scientific article Abstract: The common bean (Phaseolus vulgaris L.) is a major food legume and an important plant genetic resource for sustainable agriculture. Effective use of this diversity requires integrated evaluation of phenotypic variation and agronomic performance, with preliminary assessments of line performance across seasons. In this study, phenotypic diversity was evaluated in a subsample of the INCREASE R-core collection, a large and well-defined core set of common-bean SSD lines derived from heterogeneous germplasm lines. A total of 507 lines were characterized using 57 agro-morphological traits. Multivariate analyses revealed wide phenotypic diversity structured mainly by growth habit, phenology, and yield-related traits, with clear differentiation among lines. Mixed-data clustering identified cluster 4 as the main phenotypic group associated with higher seed- and yield-related performance and composed predominantly of indeterminate climbing landraces. Multi-trait selection indices generally ranked lines from this group highest, while early, small-seeded types tended to show lower overall performance. Evaluation of a selected subset of 19 lines across two growing seasons revealed marked year-to-year variation in yield performance, indicating contrasting responses among otherwise high-performing lines. The multi-trait genotype–ideotype distance index further distinguished lines with balanced performance across traits and years. Overall, this study shows that large-scale phenotypic characterization combined with multi-trait evaluation can provide a useful exploratory basis for identifying breeding-relevant ideotypes and promising lines for further validation for common-bean improvement. Keywords: common bean, phenotypic diversity, germplasm evaluation, multivariate analysis, selection index, year-to-year variation, yield stability Published in DiRROS: 20.04.2026; Views: 463; Downloads: 225
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3. Fatty acid composition and aromatic profile of Krškopolje and modern pig breeds reared under organic and conventional systemsMarjeta Mencin, Katja Babič, Lidija Strojnik, Zala Sel, Andrej Kastelic, Nives Ogrinc, 2026, original scientific article Abstract: Slovenia preserves one autochthonous pig breed, the Krškopolje pig, whose meat has been reported to exhibit a favourable fatty acid profile compared with that of modern breeds. However, meat quality is not solely determined by genetics; the production system also influences it, as organic and conventional farming differ in feed composition, housing and outdoor access. This study aimed to compare the effects of pig breed (Krškopolje vs. modern) and production system (organic vs. conventional) on the fatty acid composition and volatile organic compound (VOC) profile of pork. Fatty acid composition was determined by GC-FID after methylation, and the VOCs profile was obtained using headspace solid-phase microextraction (HS-SPME) coupled with GC-MS. Results showed that Krškopolje meat had higher SFA and MUFA, while modern pig meat had higher PUFAs, particularly n-6, reflecting genetic and dietary influences. Modern breeds also showed greater fatty acid response to the rearing system than the Krškopolje breed. Several VOCs were unique to modern breed pigs, indicating breed-specific differences in lipid composition, amino acid metabolism, and microbial activity. Aldehydes were the dominant VOC class in both breeds, slightly higher in Krškopolje meat. OPLS-DA model revealed breed-related differences in VOCs, pinpointing compounds likely responsible for breed-specific aroma and flavour. Keywords: Krškopolje pigs, volatile organic compounds, fatty acids, organic production, conventional production, multivariate analysis Published in DiRROS: 20.03.2026; Views: 514; Downloads: 382
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4. Quality differentiation of Kraški pršut : exploring the impact of weight, suppliers and aroma–sensory correlationsKatja Babič, Martin Škrlep, Lidija Strojnik, Marjeta Čandek-Potokar, Nives Ogrinc, 2025, original scientific article Keywords: descriptive sensory analysis, dry-cured ham, multivariate statistical analysis, volatile compounds Published in DiRROS: 02.10.2025; Views: 761; Downloads: 317
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5. Extending multivariate sub-quasi-copulasDamjana Kokol-Bukovšek, Tomaž Košir, Blaž Mojškerc, Matjaž Omladič, 2024, original scientific article Abstract: In this paper, we introduce patchwork constructions for multivariate quasi-copulas. These results appear to be new since the kind of approach has been limited to either copulas or only bivariate quasi-copulas so far. It seems that the multivariate case is much more involved, since we are able to prove that some of the known methods of bivariate constructions cannot be extended to higher dimensions. Our main result is to present the necessary and sufficient conditions both on the patch and the values of it for the desired multivariate quasi-copula to exist. We also give all possible solutions. Keywords: mathematics, multivariate analysis Published in DiRROS: 18.06.2024; Views: 1419; Downloads: 917
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6. Exploration of macromolecular phenotype of human skeletal muscle in diabetes using infrared spectroscopyBarbara Zupančič, Chiedozie Kenneth Ugwoke, Mohamed Elwy Abdelmonaem, Armin Alibegović, Erika Cvetko, Jože Grdadolnik, Anja Šerbec, Nejc Umek, 2023, original scientific article Abstract: Introduction: The global burden of diabetes mellitus is escalating, and more efficient investigative strategies are needed for a deeper understanding of underlying pathophysiological mechanisms. The crucial role of skeletal muscle in carbohydrate and lipid metabolism makes it one of the most susceptible tissues to diabetes-related metabolic disorders. In tissue studies, conventional histochemical methods have several technical limitations and have been shown to inadequately characterise the biomolecular phenotype of skeletal muscle to provide a holistic view of the pathologically altered proportions of macromolecular constituents. Materials and methods: In this pilot study, we examined the composition of five different human skeletal muscles from male donors diagnosed with type 2 diabetes and non-diabetic controls. We analysed the lipid, glycogen, and collagen content in the muscles in a traditional manner with histochemical assays using different staining techniques. This served as a reference for comparison with the unconventional analysis of tissue composition using Fourier-transform infrared spectroscopy as an alternative methodological approach. Results: A thorough chemometric post-processing of the infrared spectra using a multi-stage spectral decomposition allowed the simultaneous identification of various compositional details from a vibrational spectrum measured in a single experiment. We obtained multifaceted information about the proportions of the different macromolecular constituents of skeletal muscle, which even allowed us to distinguish protein constituents with different structural properties. The most important methodological steps for a comprehensive insight into muscle composition have thus been set and parameters identified that can be used for the comparison between healthy and diabetic muscles. Conclusion: We have established a methodological framework based on vibrational spectroscopy for the detailed macromolecular analysis of human skeletal muscle that can effectively complement or may even serve as an alternative to histochemical assays. As this is a pilot study with relatively small sample sets, we remain cautious at this stage in drawing definitive conclusions about diabetes-related changes in skeletal muscle composition. However, the main focus and contribution of our work has been to provide an alternative, simple and efficient approach for this purpose. We are confident that we have achieved this goal and have brought our methodology to a level from which it can be successfully transferred to a large-scale study that allows the effects of diabetes on skeletal muscle composition and the interrelationships between the macromolecular tissue alterations due to diabetes to be investigated. Keywords: diabetes mellitus, skeletal muscle, metabolism, macromulecular composition, infrared spectroscopy, multivariate analysis, histochemical assays Published in DiRROS: 11.01.2024; Views: 2200; Downloads: 1005
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