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- ItemAmorphous-Like Ultralow Thermal Transport in Crystalline Argyrodite Cu7PS6(Weinheim : Wiley-VCH, 2024) Shen, Xingchen; Ouyang, Niuchang; Huang, Yuling; Tung, Yung‐Hsiang; Yang, Chun‐Chuen; Faizan, Muhammad; Perez, Nicolas; He, Ran; Sotnikov, Andrei; Willa, Kristin; Wang, Chen; Chen, Yue; Guilmeau, EmmanuelDue to their amorphous-like ultralow lattice thermal conductivity both below and above the superionic phase transition, crystalline Cu- and Ag-based superionic argyrodites have garnered widespread attention as promising thermoelectric materials. However, despite their intriguing properties, quantifying their lattice thermal conductivities and a comprehensive understanding of the microscopic dynamics that drive these extraordinary properties are still lacking. Here, an integrated experimental and theoretical approach is adopted to reveal the presence of Cu-dominated low-energy optical phonons in the Cu-based argyrodite Cu7PS6. These phonons yield strong acoustic-optical phonon scattering through avoided crossing, enabling ultralow lattice thermal conductivity. The Unified Theory of thermal transport is employed to analyze heat conduction and successfully reproduce the experimental amorphous-like ultralow lattice thermal conductivities, ranging from 0.43 to 0.58 W m−1 K−1, in the temperature range of 100–400 K. The study reveals that the amorphous-like ultralow thermal conductivity of Cu7PS6 stems from a significantly dominant wave-like conduction mechanism. Moreover, the simulations elucidate the wave-like thermal transport mainly results from the contribution of Cu-associated low-energy overlapping optical phonons. This study highlights the crucial role of low-energy and overlapping optical modes in facilitating amorphous-like ultralow thermal transport, providing a thorough understanding of the underlying complex dynamics of argyrodites.
- ItemAnne Baillot: From Handwriting to Footprinting: Text and Heritage in the Age of Climate Crisis. Cambridge: Open Book Publishers, 2023, 179 Seiten, ISBN 978-1-80511-089-7, https://doi.org/10.11647/OBP.0355(Berlin : Walter de Gruyter, 2024-05-04) Schmeja, StefanReviewed Publication: Baillot Anne From Handwriting to Footprinting: Text and Heritage in the Age of Climate Crisis Cambridge Open Book Publishers 2023 179 Seiten ISBN 978-1-80511-089-7, https://doi.org/10.11647/OBP.0355
- ItemPIEZO1-mediated mechanosensing governs NK cell killing efficiency and infiltration in three-dimensional matrices([Cold Spring Harbor] : Cold Spring Harbor Laboratory (CSHL), 2024) Yanamandra, Archana K.; Zhang, Jingnan; Montalvo, Galia; Zhou, Xiangda; Biedenweg, Doreen; Zhao, Renping; Sharma, Shulagna; Hoth, Markus; Lautenschläger, Franziska; Otto, Oliver; del Campo, Aránzazu; Qu, BinNatural killer (NK) cells play a vital role in eliminating tumorigenic cells. Efficient locating and killing of target cells in complex three-dimensional (3D) environments are critical for their functions under physiological conditions. However, the role of mechanosensing in regulating NK cell killing efficiency in physiologically relevant scenarios is poorly understood. Here, we report that the responsiveness of NK cells is regulated by tumor cell stiffness. NK cell killing efficiency in 3D is impaired against softened tumor cells, while it is enhanced against stiffened tumor cells. Notably, the durations required for NK cell killing and detachment are significantly shortened for stiffened tumor cells. Furthermore, we have identified PIEZO1 as the predominantly expressed mechanosensitive ion channel among the examined candidates in NK cells. Perturbation of PIEZO1 abolishes stiffness-dependent NK cell responsiveness, significantly impairs the killing efficiency of NK cells in 3D, and substantially reduces NK cell infiltration into 3D collagen matrices. Conversely, PIEZO1 activation enhances NK killing efficiency as well as infiltration. In conclusion, our findings demonstrate that PIEZO1-mediated mechanosensing is crucial for NK killing functions, highlighting the role of mechanosensing in NK cell killing efficiency under 3D physiological conditions and the influence of environmental physical cues on NK cell functions.
- ItemDataset on permeability of wings from owls and non-silently flying birds(Amsterdam [u.a.] : Elsevier, 2024) Geyer, Thomas F.; Windisch, Thomas; Fritzsche, Christoph; Sarradj, EnnesThe very soft and flow-permeable plumage is among the special adaptations of the owl that the silent flight is attributed to. Using a specially designed apparatus that provides a low-speed volume flow of air through a small sample of porous material, measurements of the air flow permeability were performed in accordance to ISO 9053 on a total of 39 prepared wing specimen from six different bird species, including three species of silently flying owls and three non-silently flying bird species. The resulting data set described in the present paper contains the static airflow resistance measured at different positions on the wing.
- ItemFloating Zone Growth of Pure and Pb-Doped Bi-2201 Crystals(Basel : MDPI, 2024) Roslova, Maria; Büchner, Bernd; Maljuk, AndreyIn this review, we summarize recent progress in crystal growth and understanding of the influence of crystal structure on superconductivity in pure and Pb-doped Bi2Sr2CuOy (Bi-2201) materials belonging to the overdoped region of high-temperature cuprate superconductors. The crystal growth of Bi-2201 superconductors faces challenges due to intricate materials chemistry and the lack of knowledge of corresponding phase diagrams. Historically, a crucible-free floating zone method emerged as the most promising growth approach for these materials, resulting in high-quality single crystals. This review outlines the described methods in the literature and the authors’ synthesis endeavors encompassing Pb-doped Bi-2201 crystals, provides a detailed structural characterization of as-grown and post-growth annealed samples, and highlights optimal growth conditions that yield large-size, single-phase, and compositionally homogeneous Bi-2201 single crystals.
- ItemOn the Preparation and Spectroelectrochemical Characterization of Certain 2,5-Bis(het)aryl Substituted Thiophenes(Weinheim : Wiley-VCH, 2024) Dmitrieva, Evgenia; Barche, Jens; Popov, Alexey A.; Hartmann, HorstIn this work, a series of novel 2,5-bis(het)aryl and 2,5-bis-thienyl substituted thiophenes have been synthesized and characterized by ultraviolet-visible-near infrared (UV-Vis-NIR) absorption and fluorescence spectroscopy as well as cyclic voltammetry. From the electron paramagnetic resonance (EPR)/UV-Vis-NIR spectroelectrochemical data, information about the optical and magnetic properties of the charged species of these compounds have been provided. The spin distributions in the electrochemically generated radical ions were estimated experimentally and compared with theoretical data.
- ItemThe impact of chemical short-range order on the thermophysical properties of medium- and high-entropy alloys(Amsterdam [u.a.] : Elsevier Science, 2024) Andreoli, Angelo F.; Fantin, Andrea; Kasatikov, Sergey; Bacurau, Vinícius P.; Widom, Michael; Gargarella, Piter; Mazzer, Eric M.; Woodcock, Thomas G.; Nielsch, Kornelius; Coury, Francisco G.The unusual behavior observed in the coefficient of thermal expansion and specific heat capacity of CrFeNi, CoCrNi, and CoCrFeNi medium/high-entropy alloys is commonly referred to as the K-state effect. It is shown to be independent of the Curie temperature, as demonstrated by temperature-dependent magnetic moment measurements. CoCrFeNi alloy is chosen for detailed characterization; potential reasons for the K-state effect such as texture, recrystallization, and second-phase precipitation are ruled out. An examination of the electronic structure indicates the formation of a pseudo-gap in the Density of States, which suggests a specific chemical interaction between Ni and Cr atoms upon alloying. Hybrid Monte Carlo/Molecular Dynamic (MC/MD) simulations indicate the presence of non-negligible chemical short-range order (CSRO). Local lattice distortions are shown to be negligible, although deviations around Cr and Ni elements from those expected in a fully disordered structure are experimentally observed by X-ray absorption spectroscopy. The determined bonding distances are in good agreement with MC/MD calculations. A mechanism is proposed to explain the anomalies and calorimetric experiments and their results are used to validate the mechanism.
- ItemLaser powder bed fusion of Fe60(CoCrNiMn)40 medium-entropy alloy with excellent strength-ductility balance(Amsterdam [u.a.] : Elsevier Science, 2024) Yang, Shengze; Liu, Yang; Chen, Hongyu; Wang, Yonggang; Kosiba, KonradIn this study, Fe60(CoCrNiMn)40 medium-entropy alloy (MEA) was fabricated by laser powder bed fusion (LPBF) via mixing of pure Fe and FeCoCrNiMn powders, the processability, microstructure and mechanical properties were systematically investigated, and the mechanism of strengthening and toughening were revealed through combination of experiments and molecular dynamics (MD) simulations. Results show that fraction of BCC phase decreased gradually with increasing volume energy density (VED), and thus heterostructue with varying FCC and BCC phases were produced through regulating the VED. The Fe60(CoCrNiMn)40 MEA (with scanning speeds of 700 and 800 mm/s) showed excellent strength-plasticity balance (e.g. 476 MPa, 612 MPa and 63 %) compared to the equiatomic FeCoCrNiMn HEA, which is ascribed to the synergistic strengthening and toughening effects involving the twinning induced plasticity (TWIP) and the reinforcement caused by the BCC phase (act as reinforced particle) embedded in the FCC matrix.
- ItemExpanding the genetic programmability of Lactiplantibacillus plantarum(Oxford : Wiley-Blackwell, 2024) Blanch‐Asensio, Marc; Dey, Sourik; Tadimarri, Varun Sai; Sankaran, ShrikrishnanLactobacilli are ubiquitous in nature and symbiotically provide health benefits for countless organisms including humans, animals and plants. They are vital for the fermented food industry and are being extensively explored for healthcare applications. For all these reasons, there is considerable interest in enhancing and controlling their capabilities through the engineering of genetic modules and circuits. One of the most robust and reliable microbial chassis for these synthetic biology applications is the widely used Lactiplantibacillus plantarum species. However, the genetic toolkit needed to advance its applicability remains poorly equipped. This mini-review highlights the genetic parts that have been discovered to achieve food-grade recombinant protein production and speculates on lessons learned from these studies for L. plantarum engineering. Furthermore, strategies to identify, create and optimize genetic parts for real-time regulation of gene expression and enhancement of biosafety are also suggested.
- ItemCoulomb exchange as source of Kitaev and off-diagonal symmetric anisotropic couplings(London : Springer Nature, 2024) Bhattacharyya, Pritam; Petersen, Thorben; Bogdanov, Nikolay A.; Hozoi, LiviuExchange underpins the magnetic properties of quantum matter. In its most basic form, it occurs through the interplay of Pauli’s exclusion principle and Coulomb repulsion, being referred to as Coulomb or direct exchange. Pauli’s exclusion principle combined with inter-atomic electron hopping additionally leads to kinetic exchange and superexchange. Here we disentangle the different exchange channels in anisotropic Kitaev–Heisenberg context. By quantum chemical computations, we show that anisotropic Coulomb exchange, completely neglected so far in the field, may be as large as (or even larger than) other contributions — kinetic exchange and superexchange. This opens new perspectives onto anisotropic exchange mechanisms and sets the proper conceptual framework for further research on tuning Kitaev–Heisenberg magnetism.
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