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The incorporation of fluorine into amino acids is an important strategy to produce tailored building blocks with unique properties for peptide-based materials. Phenylalanine is frequently modified due to its role in cation–π interactions and the formation of amyloid fibres. Previous studies have utilized gas-phase vibrational spectroscopy to study interactions between canonical amino acids. In this study, we employ a combination of cryogenic gas-phase infrared spectroscopy and density functional theory to study the interactions in proton-bound dimers of side-chain fluorinated phenylalanines. Our findings reveal how the position and number of fluorine atoms affect the interactions and structures of the dimers. Monofluorinated phenylalanines adopt charge-solvated structures in which the two amino acids interact via their ammonium and amine functions (NH3+⋯NH2). The dimer with the perfluorinated side chain forms multiple charge-solvated and salt-bridged structures with varying interaction types. These structural changes are attributed to the significant reduction of electron density in the aromatic systems. [ABSTRACT FROM AUTHOR]

Due to energy shortages and the greenhouse effect, the efficient use of energy through phase-change materials (PCMs) is gaining increased attention. In this study, magnetic phase-change microcapsules (Mag-mc) were prepared by suspension polymerization. The shell layer of the microcapsules was formed by copolymerizing methyl methacrylate and triethoxyethylene silane, with the latter enhancing the compatibility of the shell layer with the magnetic additive. Ferric ferrous oxide modified by oleic acid (Fe3O4(m)) was added as the magnetic additive. Differential scanning calorimetry (DSC) testing revealed that the content of phase-change materials in microcapsules without and with ferric ferrous oxide were 79.77% and 96.63%, respectively, demonstrating that the addition of Fe3O4(m) improved the encapsulation efficiency and enhanced the energy storage ability of the microcapsules. Laser particle size analysis showed that the overall average particle sizes for the microcapsules without and with ferric ferrous oxide were 3.48 μm and 2.09 μm, respectively, indicating that the incorporation of magnetic materials reduced the size and distribution of the microcapsules. Thermogravimetric analysis indicated that the thermal stability of the microcapsules was enhanced by the addition of Fe3O4(m). Moreover, the infrared emissivity of the microcapsule-containing film decreased from 0.77 to 0.72 with the addition of Fe3O4(m) to the shell of microcapsules. [ABSTRACT FROM AUTHOR]

In recent years, numerous researchers have incorporated plant fibers into polymers to alter the thermal and mechanical properties of materials. Grapevines, considered agricultural waste, have led to burdens for farmers and environmental challenges due to their mass production. This study aims to reduce the brittleness of polylactic acid (PLA) by adding polybutylene succinate (PBS) as a toughening agent and employing grapevine fiber (GVF) as a biomass filler. Additionally, the influence of GVF, toughening agents, compatibilizers, and lubrication agents on the tensile strength, heat deflection temperature (HDT), and impact strength of the composites was examined. The findings revealed that the addition of 10% GVF and 5% PBS increased the impact and tensile strengths of PLA from 17.47 J/m and 49.74 MPa to 29.7 J/m and 54.46 MPa, respectively. Moreover, the HDT of the composites exceeded 120 °C when the GVF content was more than 40 wt%. Additionally, the inclusion of a compatibilizer and a lubrication agent enabled the composite containing 30% GVF to achieve tensile and impact strengths of 45.30 MPa and 25.52 J/m, respectively. Consequently, these GVF/PLA green bio-composites not only improve the mechanical and thermal properties of PLA but also promote the reuse of waste grapevines. [ABSTRACT FROM AUTHOR]

Maintaining the good mental health of Taiwanese military personnel is crucial, especially in light of incidents such as the Taiwan Strait crisis. Suicide is a leading cause of death among military personnel and alexithymia is a significant risk factor for suicidal ideation. However, the mechanisms linking alexithymia and suicidal ideation in this psychologically burdened population remain poorly understood. In total, 863 voluntary army military personnel from Taiwanese reserve brigades and combined‐arms brigades were enroled between May 2020 and February 2021. Structured questionnaires about alexithymia, perceived stress, depression, suicidal ideation, and background characteristics were used. Mediation analyses were conducted to examine the serial mediation roles of perceived stress and depression in the relationship between alexithymia and suicidal ideation. Significant positive correlations were observed between alexithymia, perceived stress, depression, and suicidal ideation in bivariate analyses. Serial mediation analyses revealed that alexithymia significantly predicted higher levels of perceived stress, subsequently leading to depressive symptoms, which were associated with suicidal ideation. Depression served as a significant mediator between alexithymia and suicidal ideation. The strongest mediating effect (71.4%) was observed in the pathway from alexithymia through perceived stress and depression to suicidal ideation. Limitations included the utilization of cross‐sectional data and a reliance on retrospective self‐report measures. Perceived stress and depression were identified as serial mediators in the association between alexithymia and suicidal ideation. Clinically, it is crucial to prioritise interventions that target emotional regulation skills and assess the presence of alexithymia to effectively reduce suicidal ideation in military personnel. [ABSTRACT FROM AUTHOR]

Consider the problem of finding a point furthest from x for each point x in a metric space ([ n ] , d) , where [ n ] = { 1 , 2 , ... , n }. We prove this problem to have a deterministic O (n) -time 1 / 3 -approximation algorithm. As a corollary, the maximum spanning tree problem in metric spaces has a deterministic O (n) -time 1 / 3 -approximation algorithm. We also give a Monte Carlo O (n 1. 5 log n) -time algorithm outputting, for each x ∈ [ n ] , a point y x ∈ [ n ] satisfying d (x , y x) ≥ Δ / 2 , where Δ ≡ max x , y ∈ [ n ] d (x , y). As a corollary, we have a Monte Carlo O (n 1. 5 log n) -time algorithm for finding a spanning tree of weight at least (1 / 2 − o (1)) Δ n in ([ n ] , d). [ABSTRACT FROM AUTHOR]

Intermetallic nanocrystals are emerging materials for energy, catalysis, and biomedical applications, but combining two or more metals at the nanoscale remains challenging. The amalgamation reaction represents a convenient method for hundreds of intermetallic compositions, as it relies on fast and efficient alloying of liquid metals into presynthesized metallic seeds. Here, Pd–Zn nanocrystals, prepared via Zn amide thermolysis on the surface of Pd nanocrystals and subsequent amalgamation alloying, are investigated. Size‐uniform nanocrystals and control over a wide range of Pd–Zn compositions are achieved. This allows deriving a phase diagram at the nanoscale, in which miscibility gaps and three phases with broad solid solutions are detected. Furthermore, the formation of homogeneous ZnO shells for Pd–Zn compositions extending beyond phase solubility limits is observed. Full chemistry control for Pd–Zn nanocrystals enables a rational choice of materials for selected energy applications, achieveing an extended lifetime of Zn‐ion batteries for Zn‐rich PdZn2 stoichiometry, superior electrocatalytic properties for nearly stoichiometric PdZn halite phase, and the stability and efficiency of high‐voltage cathodes benefiting from ZnO shell protection around Pd3Zn10 nanocrystals are reported. This paper exemplifies the multifunctionality of intermetallics Pd–Zn nanocrystals, while this methodology can be extended to many other bimetallic nanomaterials. [ABSTRACT FROM AUTHOR]