Self-Assembly of Amyloid-Beta and Its Piezoelectric Properties

Investigating amyloid nanofibril self-assembly, with an emphasis on the electromechanical property of amyloid peptides, namely, piezoelectricity, may have several important implications: 1) the self-assembly process can hinder the biological stability and give rise to the formation of amyloid structures associated with neurodegenerative diseases;2) investigations in this field may lead to an improved understanding of high-performance, functional biological nanomaterials, 3) new technologies could be established based on peptide self-assembly and the resultant functional properties, e.g., in the creation of a piezoelectric device formed with vertical diphenylalanine peptide tubes as a piezoelectric biosensor, and 4) new knowledge can be generated about neurodegenerative disorders, potentially yielding new therapies. Therefore, in this review, we will present the current investigations associated with self-assembly of amyloid-beta, the mechanisms that generate new structures, as well as theoretical calculations exploring the functionality of the structures under physiological pressure and electric field.

Active catalytic species generated in situ in zirconia incorporated hydrogen storage material magnesium hydride

This study explores how zirconia additive interacts with MgH_(2)to improve its hydrogen storage performance.Initially it is confirmed that the zirconia added MgH_(2)powder releases hydrogen at a temperature of about 50℃below that of the additive free MgH_(2).Subsequent tests by X ray diffraction(XRD)and infrared(IR)spectroscopy techniques reveal that the ZrO_(2) mixed MgH_(2)powder contains ZrHx(2<x>1.5)and MgO secondary phases.This observation is supported by the negative Gibbs free energy values obtained for the formation of ZrH_(2)/MgO from ZrO_(2)/MgH_(2)powder samples.An X ray photoelectron spectroscopy(XPS)study reveals that apart from Zr^(4+)cations,Zr^(2+) and zero valent Zr exist in the powder.Atomic force microscopy(AFM)study reveals that the average grain size is 20 nm and the elemental line scan profiles further proves the existence of oxygen deficient Zr bearing phase(s).This study strengthens the belief that functional metal oxide additives in fact chemically interact with MgH_(2)to make active in-situ catalysts in the MgH_(2)system.

Comprehensive investigation of structural,dielectric and local piezoelectric properties of KNN ceramics

In this research paper,we utilized the traditional high-temperature solid-state reaction method to fabricate the K_(0.495)Na_(0.520)NbO_(3),K_(0.480)Na_(0.535)NbO_(3)and K_(0.475)Na_(0.540)NbO_(3)(abbreviated as KNN-1,KNN-2,and KNN-3,respectively)lead-free ion deficient ceramics for understanding the influence of ionic deficiency on the crystalline structure and dielectric/piezoelectric properties of the samples.X-ray diffraction patterns of these samples exhibited a perovskite tetragonal phase.Dielectric anomalies around 287℃and 471℃were identified as ferroelectric to ferroelectric and ferroelectric to paraelectric-transition temperatures for KNN-2 at 1 kHz.It was found that the composition KNN-2 exhibit relatively high Curie temperature i.e.,471℃.The conductivity plots confirm that the activation energies are frequency-dependent.The impedance behavior in our ceramic samples can be analyzed with the bulk/grain effect.The slope of Z′with temperature shows negative temperature coefficient of resistance(NTCR)type behavior in proposed KNN ceramics material.

FERROELECTRIC AND MAGNETIC PROPERTIES OF PEROVSKITE STRUCTURED Bi_(1-x-y)Gd_(x)Ba_(y)Fe_(1-y)Ti_(y)O_(3)MAGNETOELECTRIC CERAMICS

Ternary solid solutions of BiFeO_(3),GdFeO_(3)and BaTiO_(3)have been prepared by solid-state reaction method.Dielectric properties of these ceramics have been characterized in the tem-perature range between room temperature and 673 K and magnetic properties between 5 K and 300K.For the understanding of the multiferroic property,the relation between the crystal structures,magnetic transition and ferroelectric transitions with increasing temperature have been analyzed.All ceramic samples show single perovskite phase.When Ba content exceeds 0.2 wt%,the sintering ability is weakened and the phase structure of Bi_(1-x-y)Gd_(x)Ba_(y)Fe_(1-y)Ti_(y)O_(3)(with x=0.2 and y=0.1,0.2,0.3,0.4,0.5)solid solution changes from rhombohedral to tetragonal phase.The maximum ferroelectric transition temperature(T_(c))of this system was in the range 154-165℃with the dielectric constant peak of 6000 for y=0.5 at 100 kHz.Well-saturated piezoresponse hysteresis loops were observed for all compositions indicating room temperature ferroelectricity.With increasing Ba content(up to 0.3 wt%)the remanent magnetization M,increased and the coercive magnetic field decreased.