Double-loop hysteresis of multisite dilute Sr(Y1−x_{1-x}Dyx_x)2_2O4_4 single crystal Kramers paramagnets: electron-phonon interaction, quantum tunneling and cross-relaxation

Experimental and theoretical studies of the dynamic magnetization in swept magnetic fields of the orthorhombic SrY$_2$O$_4$ single-crystals doped with the Dy$^{3+}$ Kramers ions (0.01 and 0.5 at.%) with natural abundances of even and odd Dy isotopes are presented. Impurity ions substitute for Y$^{3+}$ ions at two nonequivalent crystallographic sites with the same local $C_s$ symmetry but strongly different crystal fields. Well pronounced double-loop hysteresis is observed at temperatures 2, 4, 5 and 6 K for sweeping rates of 5 and 1 mT/s. The microscopic model of spectral, magnetic and kinetic properties of Dy$^{3+}$ ions is developed based on the results of EPR, site selective optical spectra and magnetic relaxation measurements. The derived approach to the dynamic magnetization in the sweeping field based on the numerical solution of generalized master equations with time-dependent transition probabilities induced by the electron-phonon interaction, quantum tunneling and cross-relaxation allowed us to reproduce successfully the evolution of the hysteresis loop shape with temperature, sweeping rate and concentration of paramagnetic ions.Comment: 11 pages, 6 figures, 2 tables, 52 reference

An Effect of Fe³⁺ Ion Substitution for Cr³⁺ in the Octahedral Sites of FeCr₂O₄ Multiferroic Spinel: Mössbauer Spectroscopy Study

We present the results of a successful synthesis and investigation of polycrystalline Fe2+(Cr3+, Fe3+)2O4 powder, where 1/8 part of the Cr3+ ions in the octahedral sites is substituted by the Fe3+ ones. It is shown that under such doping, the material retains the cubic spinel structure characteristic of the parent FeCr2O4 compound. However, the values of the critical temperatures have changed. Both the orbital and magnetic orderings occur at about 120 K, and magnetic structure rearrangement associated with an onset of spiral modulation takes place at 26 K. Mössbauer studies in a wide temperature range make it possible to accurately control the content of iron ions, their valence and magnetic states, and local environment, therefore, allowing a deeper understanding of the features of the revealed transformations

Endotaxial α-Fe Nanoparticles in the High-Fluence Iron-Implanted Single-Crystal MgO

In this work, we report on the endotaxial growth of α-Fe nanoparticles in the near-surface layer under high-fluence iron ion implantation of the single-crystal magnesium oxide substrate. Comprehensive Mössbauer effect and magnetometry studies show that the implanted sample reveals a pronounced ferromagnetic response even at room temperature, and the α-Fe nanoparticles serve as its main source. The broad band at ~1000 Oe in the X-band magnetic resonance spectra originates from the α-Fe fraction. It manifests the properties of the easy-plane system with the four-fold in-plane anisotropy. The last indicates that the α-Fe nanoparticles are coherently incorporated into the host MgO matrix

Correction: GATAD2B-associated neurodevelopmental disorder (GAND): clinical and molecular insights into a NuRD-related disorder

An amendment to this paper has been published and can be accessed via a link at the top of the paper

GATAD2B-associated neurodevelopmental disorder (GAND) : clinical and molecular insights into a NuRD-related disorder

Copyright © 2020, American College of Medical Genetics and GenomicsPurpose: Determination of genotypic/phenotypic features of GATAD2B-associated neurodevelopmental disorder (GAND). Methods: Fifty GAND subjects were evaluated to determine consistent genotypic/phenotypic features. Immunoprecipitation assays utilizing in vitro transcription-translation products were used to evaluate GATAD2B missense variants' ability to interact with binding partners within the nucleosome remodeling and deacetylase (NuRD) complex. Results: Subjects had clinical findings that included macrocephaly, hypotonia, intellectual disability, neonatal feeding issues, polyhydramnios, apraxia of speech, epilepsy, and bicuspid aortic valves. Forty-one novelGATAD2B variants were identified with multiple variant types (nonsense, truncating frameshift, splice-site variants, deletions, and missense). Seven subjects were identified with missense variants that localized within two conserved region domains (CR1 or CR2) of the GATAD2B protein. Immunoprecipitation assays revealed several of these missense variants disrupted GATAD2B interactions with its NuRD complex binding partners. Conclusions: A consistent GAND phenotype was caused by a range of genetic variants in GATAD2B that include loss-of-function and missense subtypes. Missense variants were present in conserved region domains that disrupted assembly of NuRD complex proteins. GAND's clinical phenotype had substantial clinical overlap with other disorders associated with the NuRD complex that involve CHD3 and CHD4, with clinical features of hypotonia, intellectual disability, cardiac defects, childhood apraxia of speech, and macrocephaly.Research reported in this paper was supported by the National Institutes of Health (NIH) Common Fund, through the Office of Strategic Coordination/Office of the NIH Director under award number U01HG007672. The content is solely the responsibility of the authors and does not necessarily represent the official views of the NIH. GAND50’s seq+ analysis was supported by NIH National Center for Advancing Translational Science (NCATS) UCLA Clinical and Translational Science Institute (CTSI) grant number UL1TR001881. J.P.M. received funding from the National Health and Medical Research Council (APP1012161, APP1063301, APP1126357, APP1058916). T.M.P. and this research was supported by the Cedars-Sinai institutional funding program and the Cedars-Sinai Diana and Steve Marienhoff Fashion Industries Guild Endowed Fellowship in Pediatric Neuromuscular and the Fashion Industries Guild Endowed Fellowship for the Undiagnosed Diseases Program. T.M.P. is especially grateful for the wonderful and continued support from the Cedars-Sinai Fashion Industries Guild.info:eu-repo/semantics/publishedVersio