1671. A simple cryotransfer method for 3D electron diffraction measurements of highly sensitive samplesKshitij Gurung, Erik Uran, Klemen Motaln, Petr Brázda, Kristian Radan, Matic Lozinšek, Lukáš Palatinus, 2025, original scientific article Keywords: 3D electron diffraction, cryotransfer, xenon fluorides, noble-gas compounds
Published in DiRROS: 05.05.2025; Views: 454; Downloads: 267
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1673. Mitochondrial sensitivity to submaximal [ADP] following bed rest : a novel two-phase approach associated with fibre typesLucrezia Zuccarelli, Maria De Martino, Antonio Filippi, Alice E. Knapton, Benjamin D. Thackray, Giovanni Baldassarre, Boštjan Šimunič, Rado Pišot, Giuseppe Sirago, Elena Monti, Marco Vincenzo Narici, Miriam Isola, Andrew J. Murray, Giovanna Lippe, Bruno Grassi, 2025, original scientific article Abstract: Background: We recently demonstrated that following a 10-day exposure to inactivity/simulated microgravity impairments ofoxidative metabolism were located ‘upstream’ of mitochondrial function, as evaluated by maximal ADP-stimulated mitochon-drial respiration (JO 2max) determined ex vivo. The aim of this study was to evaluate mitochondrial sensitivity to submaximal[ADP] by an alternative approach aimed at identifying responses associated with fibre type composition.Methods: Isolated permeabilized vastus lateralis fibres were analysed by high-resolution respirometry in 9 young males beforeand after a 10-day horizontal bed rest. Eleven submaximal titrations of ADP (from 12.5 to 10 000 μM) were utilized to assess com-plex I + II-linked ADP sensitivity. We applied to JO 2 versus [ADP] data a traditional Michaelis–Menten kinetics equation, withthe calculation of the apparent K m and maximal respiration (Vmax), and two ‘sequential’ hyperbolic equations, yielding two K mand Vmax values. The two-hyperbolic equations were solved and the [ADP] value corresponding to 50% of JO 2max was calculated.Isoform expression of myosin heavy chains (MyHC) 1, 2A and 2X was also determined. Control experiments were also carriedout on rat skeletal muscle samples with different percentages of MyHC isoforms.Results: The two hyperbolic equations provided an alternative fitting of data and identified two distinct phases of the JO 2 versus[ADP] response: a first phase characterized by low Vmax (Vmax1 , 28 ± 10 pmol s−1 mg−1) and apparent K m (K m1 , 62 ± 54 μM) anda second phase characterized by higher Vmax (Vmax2 , 61 ± 16 pmol s−1 mg−1) and K m (K m2 , 1784 ± 833 μM). Data were confirmedin control experiments carried out in rat muscle samples with different percentages of MyHC isoforms. Correlation and receiveroperating characteristics analyses suggest that the two phases of the response were related to the % of MyHC isoforms.Conclusions: A novel mathematical approach (two sequential hyperbolic functions) for the fitting of JO 2 versus [ADP] data ob-tained by high-resolution respirometry on permeabilized skeletal muscle fibres, obtained in humans and rats, provided an alter-native fitting of the experimental data compared to the traditional Michaelis–Menten kinetics equation. This alternative modelallowed the identification of two distinct phases in the responses, which were related to fibre type composition. A first phase, characterized by low apparent K m and Vmax values, was correlated with the percentage of less oxidative (Type 2A + 2X) MyHCisoforms. A second phase, characterized by high apparent K m and Vmax , was related to more oxidative (Type 1) MyHC isoforms.
Keywords: ADP, bed rest, mitochondrial sensitivity, myosin heavy chains, skeletal muscle mitochondria
Published in DiRROS: 05.05.2025; Views: 473; Downloads: 278
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1675. Talent policy : problems and solutionsCatherine M. Robb, Tammy Harel Ben Shahar, Kirsten Meyer, Barbara Vetter, Henderien W. Steenbeek, Mitja Sardoč, Ruud J. R. Den Hartigh, 2025, original scientific article Abstract: The identification and development of talent have long been a central target of policy making invarious domains, including education, sports, the arts and business. Given the importance of tal-ent for success in a competitive global market, governments and businesses across the globe con-tinually devise strategic policies to identify, attract and preserve both national and internationaltalent. Most of these talent-related practices and policies (implicitly) assume that a person’s talentis predetermined and fixed, that it is readily identifiable and that effective talent developmentrequires early identification and specific, targeted training. However, these assumptions areproblematically unsupported by recent empirical and conceptual scientific research. Instead,the research shows that talent development is dynamic and context-dependent, and that earlyidentification is an unreliable predictor of future performance. We outline the conceptual ambi-guity and empirical flaws involved in current talent-related practices and propose three specificsolutions to improve policy.
Keywords: talent, talent development, talent identification, skill, policy, ethics
Published in DiRROS: 05.05.2025; Views: 466; Downloads: 248
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1676. The mediating role of the 5Cs of PYD in the relationship between grit and academic adjustment in Spanish undergraduatesDiego Gomez-Baya, Ana Kozina, Jet Uy Buenconsejo, José Antonio Muñiz-Velázquez, 2025, original scientific article Keywords: education, grit, positive youth development, academic adjustment, undergraduates, youth
Published in DiRROS: 05.05.2025; Views: 428; Downloads: 241
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1679. Improving the HER activity and stability of Pt nanoparticles by titanium oxynitride supportMilutin Smiljanić, Stefan R. Panić, Marjan Bele, Francisco Ruiz-Zepeda, Luka Pavko, Lea Gašparič, Anton Kokalj, Miran Gaberšček, Nejc Hodnik, 2022, original scientific article Published in DiRROS: 30.04.2025; Views: 586; Downloads: 292
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1680. Durable polyacrylic/siloxane-silica coating for the protection of cast AlSi7Mg0.3 alloy against corrosion in chloride solutionPeter Rodič, Barbara Kapun, Ingrid Milošev, 2023, original scientific article Abstract: This study presented a novel corrosion protective coating based on polyacrylic/siloxane-silica (PEHA-SS) deposited on lightweight cast aluminium alloy AlSi7Mg0.3. The synthesis of PEHA-SS comprises organic monomer 2-ethylhexyl acrylate and organically modified silane 3-(trimethoxysilyl)propyl methacrylate as well as an inorganic silane, tetraethyl orthosilicate. The steps during the synthesis process were monitored using real-time infrared spectroscopy. The coating deposited onto the AlSi7Mg0.3 surface was characterised using various techniques, including infrared spectroscopy, 3D contact profilometry, and scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy. The corrosion resistance of the coated alloy in sodium chloride solutions was evaluated using electrochemical impedance spectroscopy. The accelerated testing of the uncoated and coated sample was performed using the Machu test. This novel, nine micrometres thick PEHA-SS coating achieved durable corrosion (barrier) protection for the AlSi7Mg0.3 alloy in 0.1 M NaCl during the first four months of immersion or under accelerated corrosion conditions in a Machu chamber containing NaCl, acetic acid, and hydrogen peroxide at 37 °C.
Keywords: aluminum alloys, corrosion, hybrid sol-gel, Machu test
Published in DiRROS: 30.04.2025; Views: 540; Downloads: 276
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