61. Differential scanning calorimetry of proteins and Zimm–Bragg model in waterKnarik Yeritsyan, Artem Badasyan, 2019, original scientific article Abstract: Differential Scanning Calorimetry (DSC) is a regular and powerful tool to measure the specific heat profile of various materials. Hydrogen bonds play a crucial role in stabilizing the three-dimensional structure of proteins. Naturally, information about the strength of hydrogen bonds is contained in the measured DSC profiles. Despite its obvious importance, there is no approach that would allow the extraction of such information from the heat capacity measurements. In order to connect the measured profile to microscopic properties of a polypeptide chain, a proper model is required to fit. Using recent advances in the Zimm–Bragg (ZB) theory of protein folding in water, we propose a new and efficient algorithm to process the DSC experimental data and to extract the H-bonding energy among other relevant constants. Thus, for the randomly picked set of 33 proteins, we have found a quite narrow distribution of hydrogen bonding energies from 1 to 8 kJ/mol with the average energy of intra-protein hydrogen bonds kJ/mol and the average energy of water–protein bonds as kJ/mol. This is an important illustration of a tiny disbalance between the water–protein and intraprotein hydrogen bonds. Fitted values of the nucleation parameter belong to the range from 0.001 to 0.01, as expected. The reported method can be considered as complementary to the classical two-state approach and together with other parameters provides the protein–water and intraprotein H-bonding energies, not accessible within the two-state paradigm. Keywords: protein folding, differential scanning calorimetry, heat capacity, two-state model, Hawley model Published in RUNG: 26.08.2024; Views: 252; Downloads: 2
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62. Gaia22dkvLb : a microlensing planet potentially accessible to radial-velocity characterizationZexuan Wu, Subo Dong, Tuan Yi, Zhuokai Liu, Kareem El-Badry, Andrew Gould, Łukasz Wyrzykowski, K. A. Rybicki, Mateusz Bronikowski, 2024, original scientific article Abstract: We report discovering an exoplanet from following up a microlensing event alerted by Gaia. The event Gaia22dkv is toward a disk source rather than the traditional bulge microlensing fields. Our primary analysis yields a Jovian planet with M_p = 0.59 (+0.15, -0.05) M_J at a projected orbital separation r_perpendicular = 1.4 (+0.8, -0.3) au, and the host is a ∼1.1 M⊙ turnoff star at ∼1.3 kpc. At r' ~= 14, the host is far brighter than any previously discovered microlensing planet host, opening up the opportunity to test the microlensing model with radial velocity (RV) observations. RV data can be used to measure the planet's orbital period and eccentricity, and they also enable searching for inner planets of the microlensing cold Jupiter, as expected from the "inner–outer correlation" inferred from Kepler and RV discoveries. Furthermore, we show that Gaia astrometric microlensing will not only allow precise measurements of its angular Einstein radius θ_E but also directly measure the microlens parallax vector and unambiguously break a geometric light-curve degeneracy, leading to the definitive characterization of the lens system. Keywords: gravitational microlensing exoplanet detection, planetary astrophysics, astrophysics of galaxies, instrumentation astrophysics, methods for astrophysics, solar astrophysics, stellar astrophysics Published in RUNG: 23.08.2024; Views: 317; Downloads: 4
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63. Hydrazone-linked covalent organic framework catalyst via efficient Pd recovery from wastewaterMahira Bashri, Sushil Kumar, Pallab Bhandari, Sasi Stephen, Matthew J. O'Connor, Safa Gaber, Tina Škorjanc, Matjaž Finšgar, Gisha Elizabeth Luckachan, Blaž Belec, 2024, original scientific article Abstract: Global consumption and discharge of palladium (Pd) have raised environmental concerns but also present an opportunity for the sustainable recovery and reuse of this precious metal. Adsorption has proven to be an efficient method for the selective recovery of Pd from industrial wastewater. This study investigated a hydrazone-linked covalent organic framework (Tfpa-Od COF) as a potential material for the high-affinity adsorption of Pd2+ ions from wastewater, achieving a Kd value of 3.62 × 106 mL g–1. The electron-rich backbone of the COF contributes to its excellent selective removal efficiency (up to 100%) and adsorption capacity of 372.59 mg g–1. Furthermore, the Pd-adsorbed COF was evaluated as a sustainable catalyst for the Suzuki–Miyaura coupling reaction, demonstrating good catalytic conversion and recyclability. This work attempts to showcase a protocol for reusing waste palladium generated in water to fabricate heterogeneous catalysts and, thereby, promote the circular economy concept. Keywords: covalent organic frameworks, sustainability, catalysis, palladium adsorption, water purification Published in RUNG: 22.08.2024; Views: 358; Downloads: 4
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64. Single crystal synthesis and surface electronic structure of Bi_{1.993}Cr_{0.007}Se_{3}Sandra Gardonio, Zipporah Rini Benher, Mattia Fanetti, Paolo Moras, Polina M. Sheverdyaeva, Matjaž Valant, 2024, original scientific article Keywords: topological insulators, magnetic atoms, crystal synthesis, formation of clusters, surface electronic structure Published in RUNG: 21.08.2024; Views: 353; Downloads: 3
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65. Negative pragmatic transfer in bilinguals : cross‑linguistic influence in the acquisition of quantifiersGreta Mazzaggio, Penka Stateva, 2024, original scientific article Abstract: Building on the cross-linguistic variability in the meaning of vague quantifiers, this study explores the potential for negative transfer in Italian-Slovenian bilinguals concerning the use of quantificational determiners, specifically the translational equivalents of the English “many”, that is the Slovenian "precej" and "veliko". The aim is to identify relevant aspects of pragmatic knowledge for cross-linguistic influence. The study presents the results of a sentence-picture verification task in which Slovenian native speakers and Italian-Slovenian bilinguals evaluated sentences of the form "Quantifier X are Y" in relation to visual contexts.
The results suggest that Italian learners of Slovenian, unlike Slovenian native speakers, fail to distinguish between "precej" and "veliko". This finding aligns with the negative transfer hypothesis. The study highlights the potential role of pragmatic knowledge in cross-linguistic transfer, particularly in the context of vague quantifiers. Keywords: quantification, cross-linguistic differences, pragmatics, semantics, negative transfer Published in RUNG: 20.08.2024; Views: 427; Downloads: 5
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67. Host plants and vectors of grapevine Flavescence dorée phytoplasmKseniia Annenkova, 2024, research project (high school) Abstract: Understanding the epidemiology of Flavescence dorée (FD), a devastating grapevine disease caused by the phytoplasma (FDp), is crucial for developing effective management strategies. This study aimed to provide a comprehensive overview of the host plants and vectors of FDp. Key methods included a review of existing literature and analysis of genetic data to identify potential transmission pathways. The results revealed that FDp infects a wide range of plant species beyond grapevines, complicating control measures. While the leafhopper Scaphoideus titanus is the primary vector, several occasional vectors such as Orientus ishidae, Dictyophara europaea, Phlogotettix cyclops etc. also play roles in transmission. The study identified 22 map genotypes of the 16SrV phytoplasma, categorized into three main clusters (Map-FD1, Map-FD2, and Map-FD3), which are primarily associated with S. titanus and grapevine. The research emphasizes the importance of ongoing studies to further understand the geographic distribution and genotypic variability of FDp, which is crucial for refining control strategies and ensuring their success. Enhanced knowledge of FDp genotypes and their interactions with different vectors and host plants will help in improving targeted and effective disease management interventions. Keywords: Flavescence dorée phytoplasma, grapevine, vectors, host plants, genetic diversity Published in RUNG: 19.08.2024; Views: 371; Downloads: 0 This document has many files! More... |
68. The effect of prolonged maceration with spontaneous fermentation on chemical and sensorial characteristics of white wineTara Seničić, 2024, research project (high school) Abstract: The use of prolonged maceration and spontaneous fermentation in white wine production is gaining renewed interest among winemakers, considering rising consumer interest in sustainable and traditional winemaking. This seminar aimed to assess how these approaches influence the sensory and chemical profiles of white wines based on available literature. Additionally, chemical analyses were conducted on three ‘Ribolla gialla’ variety wines from Vipava valley, which were produced using the aforementioned technology. The analyses indicated the presence of a wide range of aromatic compounds including esters and C-6 alcohols found in ‘Ribolla gialla’ wine samples. Spoilage indicators such as 4-ethylguaiacol and 4-ethylphenol were detected in some ‘Ribolla gialla’ samples, highlighting the risks of spontaneous fermentation. Assessing the reviewed literature data, prolonged maceration can enhance the aromatic complexity of white wines as related to the higher content of monoterpenes and phenolic compounds. This study supports the potential of these traditional methods to create unique and complex wines, but further research is needed to optimize these technological approaches and ensure consistent quality. Keywords: white wine, prolonged maceration, spontaneous fermentation, sensorial characteristics Published in RUNG: 19.08.2024; Views: 347; Downloads: 0 This document has many files! More... |
69. New achievements in orbital angular momentum beam characterization using a Hartmann wavefront sensor and the Kirkpatrick-Baez active optical system KAOSLuka Novinec, Matteo Pancaldi, Flavio Capotondi, Giovanni De Ninno, Francesco Guzzi, George Kourousias, Emanuele Pedersoli, Barbara Ressel, Benedikt Rösner, Alberto Simoncig, 2024, original scientific article Abstract: Advances in physics have been significantly driven by state-of-the-art technology, and in photonics and X-ray science this calls for the ability to manipulate the characteristics of optical beams. Orbital angular momentum (OAM) beams hold substantial promise in various domains such as ultra-high-capacity optical communication, rotating body detection, optical tweezers, laser processing, super-resolution imaging etc. Hence, the advancement of OAM beam-generation technology and the enhancement of its technical proficiency and characterization capabilities are of paramount importance. These endeavours will not only facilitate the use of OAM beams in the aforementioned sectors but also extend the scope of applications in diverse fields related to OAM beams. At the FERMI Free-Electron Laser (Trieste, Italy), OAM beams are generated either by tailoring the emission process on the undulator side or, in most cases, by coupling a spiral zone plate (SZP) in tandem with the refocusing Kirkpatrick–Baez active optic system (KAOS). To provide a robust and reproducible workflow to users, a Hartmann wavefront sensor (WFS) is used for both optics tuning and beam characterization. KAOS is capable of delivering both tightly focused and broad spots, with independent control over vertical and horizontal magnification. This study explores a novel non-conventional `near collimation' operational mode aimed at generating beams with OAM that employs the use of a lithographically manufactured SZP to achieve this goal. The article evaluates the mirror's performance through Hartmann wavefront sensing, offers a discussion of data analysis methodologies, and provides a quantitative analysis of these results with ptychographic reconstructions. Keywords: tailored photonics beams, orbital angular momentum of light, wavefront sensing, ptychography Published in RUNG: 19.08.2024; Views: 418; Downloads: 2
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