Hydration is an important factor in regulating the phase behaviour of lipids and besides affects their interactions with other compounds relevant for biological membranes. We present a reliable and fast method to detect and characterise hydration-induced phase transitions in phospholipids by means of small-angle synchrotron X-ray scattering. Films consisting of aggregations of representatives of the two important lipid classes lecithins (DPPC a, POPC and OPPC,a for abbreviations, see below) and cephalins (DPPE and DOPE) were investigated at room temperature in dependence on relative humidity. Qualitative changes in the sets of the diffraction patterns obtained in dynamic hydration/dehydration scans were taken as markers indicating the existence of lyotropic phase transitions. The efficiency of this methodology is demonstrated by illustrating the course of hydration-driven phase transitions between lamellar as well as nonlamellar phases. In detail, this was realised for chain melting in the mixed-chain lipids, POPC and OPPC, and for a novel nonlamellar-phase transition for DOPE between a disordered inverted ribbon phase designated as Palpha and the canonical H(II), phase, respectively.
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http://dx.doi.org/10.1080/07391102.2001.10506745 | DOI Listing |
Nat Commun
January 2025
Department of Applied Physics, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan.
Recent studies on topological materials are expanding into the nonlinear regime, while the central principle, namely the bulk-edge correspondence, is yet to be elucidated in the strongly nonlinear regime. Here, we reveal that nonlinear topological edge modes can exhibit the transition to spatial chaos by increasing nonlinearity, which can be a universal mechanism of the breakdown of the bulk-edge correspondence. Specifically, we unveil the underlying dynamical system describing the spatial distribution of zero modes and show the emergence of chaos.
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January 2025
School of Physics, Beihang University, Haidian District, Beijing, China.
Topology is being widely adopted to understand and to categorize quantum matter in modern physics. The nexus of topology orders, which engenders distinct quantum phases with benefits to both fundamental research and practical applications for future quantum devices, can be driven by topological phase transition through modulating intrinsic or extrinsic ordering parameters. The conjoined topology, however, is still elusive in experiments due to the lack of suitable material platforms.
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January 2025
State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing, China.
Dielectric-based energy storage capacitors characterized with fast charging and discharging speed and reliability play a vital role in cutting-edge electrical and electronic equipment. In pursuit of capacitor miniaturization and integration, dielectrics must offer high energy density and efficiency. Antiferroelectrics with antiparallel dipole configurations have been of significant interest for high-performance energy storage due to their negligible remanent polarization and high maximum polarization in the field-induced ferroelectric state.
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January 2025
Department of Physics, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Korea.
A particle current generated by pumping in the absence of gradients in potential energy, density or temperature is associated with non-trivial dynamics. A representative example is charge pumping that is associated with the quantum Hall effect and the quantum anomalous Hall effect. Spin pumping, the spin equivalent of charge pumping, refers to the emission of a spin current by magnetization dynamics.
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January 2025
School of Chemical and Biological Engineering, Institute of Chemical Processes, Seoul National University, Seoul, Republic of Korea.
Colloidal nanocrystals inherently undergo structural changes during chemical reactions. The robust structure-property relationships, originating from their nanoscale dimensions, underscore the significance of comprehending the dynamic structural behavior of nanocrystals in reactive chemical media. Moreover, the complexity and heterogeneity inherent in their atomic structures require tracking of structural transitions in individual nanocrystals at three-dimensional (3D) atomic resolution.
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