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The elastic properties of rutile transition metal dioxides XO₂ (X = Ru, Rh, Os, and Ir) are investigated using first-principles calculations based on density functional theory. Elastic constants, bulk modulus, shear modulus, and Young's modulus as well as Possion ratio are given. OsO₂ and IrO₂ show strong incompressibility. The hardness estimated for these dioxides shows that they are not superhard solids. The obtained Debye temperatures are comparative to those of transition metal dinitrides or diborides.

First-principles study of elastic, electronic and optical properties of full-Heusler Co₂V(Al, Ge, Ga and Si) compounds are calculated through density functional theory (DFT) to obtain and compare the mentioned properties. Equilibrium lattice constants of these compounds are in good agreement with other works. Electronic calculations are shown full spin polarization at Fermi level for all compounds, so in the down spin, indirect bandgap is calculated as 0.33, 0.6, 0.2 and 0.8 eV for Co₂V(Al, Ge, Ga and Si), respectively. The integer amounts of the magnetic moments are compatible with Slater–Pauling role. The optical treatment of Co₂VGa is different from three other compounds. All mentioned compounds have metallic behavior by 22 eV plasmonic frequency. The imaginary part of the dielectric function for the up spin indicates that the main optical transitions occurred in this spin mode. Moreover, the elastic results show that the Co₂VGa does not have elastic stability, but the other three compounds have fully elastic stability and the Co₂V(Al, Ge and Si) belong to the hardness of materials.

The structure of ZrB₂ under high-pressure was predicted by Particle Swarm Optimization method (CALYPSO). We investigated the structure stability, phonon dispersion curve, elasticity, electronic structure and thermodynamic properties of ZrB₂ under high-pressure and high-temperature via first-principles calculations. It maintained the hexagonal structure when the pressure lowers below 600 GPa at 0 K, which is confirmed by the calculated phonon dispersion curve. Studies indicate that the elastic modulus and Poisson’s ratio increase monotonically with pressure, as supported by some theoretical and experimental evidences. Calculated anisotropic factors demonstrate that compression and shear isotropy of ZrB₂ weakens as the pressure increases. Using the quasi-harmonic approximation Debye model, the Debye temperature, sound velocity, expansion coefficient, thermal capacity under the high-temperature and pressure were also predicted.

Elastic properties of iron-based superconductor Ba(Fe_1-xCo_x)₂As₂ with various Co concentrations x were reviewed. Among all elastic constants, C₆₆ shows remarkable softening associated with the structural transition from tetragonal to orthorhombic. The amount of anomaly in C₆₆ is 90% for the underdoped samples of x < 0.07 For the overdoped samples, the anomalies in C₆₆ gradually disappear with the increasing of Co concentration. The elastic compliance S₆₆ (= 1/C₆₆) shows a quantum critical behavior, which behaves just like the magnetic susceptibility of unconventional superconductors. There exists a clear correlation between the superconducting transition temperature and the amount of anomaly in S₆₆. It was suggested that the structural fluctuation, which is measured by S₆₆, plays an important role in the emergence of superconductivity. The elastic anomaly of Ba(Fe_1-xCo_x)₂As₂ is characterized by a strong electron–lattice coupling, which would be originated from the 3d orbitals of iron. This might be a universal phenomenon not only in iron-based superconductors but also d-electron based superconductors. The results on Ba(Fe_1-xCo_x)₂As₂ would reveal relevant roles of the structural fluctuations due to the orbitals, which should be taken into account for the understanding of a whole picture of the superconductivity in iron-based superconductors and related materials.

Immunoglobulin A nephropathy (IgAN) has been recognized as the most prevalent form of glomerulonephritis with various histologic and clinical phenotypes in the world. The Gal-deficient IgA1 with terminally exposed GalNAc residue(s) plays a key role in the pathogenesis of the disease. In this study, a novel colorimetric biosensor based on Helix aspersa agglutinin (HAA) absorbed on polydiacetylene (PCDA) nanovesicles for N-acetylgalactosamine (GalNAC) molecular as core framework of Gal-deficient IgA1 recognition was investigated using the high affinity between lectin HAA and GalNAC. The PCDA nanovesicles were prepared via UV crosslinking. The size, morphology and elastic property of the nanovesicles were tested. The optimal concentration of HAA for the recognition of GalNAC via naked eyes observation was 3 mM and the critical concentration of GalNAC for the sensitive color transition was 2 μg/mL. This novel method has many advantages such as low prices, intuitive, real-time and easy to carry out and great potential in Gal-deficient IgA1 detection.

The elastic properties of KF-substituted perovskite lead titanate (PbTiO₃) were investigated by dielectric measurements and Brillouin light scattering. The ferroelectric phase transition occurred at substantially lower temperature due to KF substitution, which was attributed to the modification of the covalency in Pb–O and Ti–O bonds. The longitudinal acoustic (LA) mode of KF-substituted PbTiO₃ showed a frequency softening in the paraelectric phase, which was accompanied by increasing acoustic damping. This indicated that polarization fluctuations responsible for the acoustic anomalies were enhanced by KF substitution.