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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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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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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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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
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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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