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The monomeric red fluorescent protein DsRed (mDsRed) is an optical probe widely used in multicolor applications in flow cytometry and fluorescence microscopy. Although the crystal structure of monomeric DsRed has been determined, its molecular dynamics have not been fully elucidated. To better understand its molecular flexibility, the crystal structure of mDsRed was recently determined, and its structure and temperature factors were analyzed. Solvent-accessible hole connected with the mDsRed chromophore was observed on the mDsRed surface structure. Electron density map analysis showed the tyrosine-ring group of the mDsRed chromophore in a cis-conformation, exhibiting flexibility with a nonplanar configuration between the tyrosine and imidazoline rings of the chromophore. Temperature factor analysis indicated that the top and bottom of the β-barrel are relatively flexible. These structural findings extended our understanding of the molecular flexibility of mDsRed. The detailed data collection and structure determination reported in this study can be used for future structural analyses.

In this study we use micromagnetic modeling to show that the magnetizations of magnetically single‐vortex particles rotate toward the stress axis on the application of a differential compression stress. This is the exact opposite response to magnetically single‐domain particles, which previously provided the theoretical underpinning of the effect of stress on the magnetic signals of rocks. We show that the magnetization directions of single‐vortex and equant single‐domain particles are altered by much lower stresses than previously predicted, c.f., 100 versus 1,000 MPa; where a change in magnetization is defined as a rotation of >3° after the removal of stress. The magnetization intensity of assemblages also drops by ∼20%–30% on the application and removal of stress of ∼100 MPa. Given that single‐vortex particles are now thought to dominate the magnetization of most rocks, future studies should account for paleomagnetic directional uncertainties and potential underestimation of the ancient magnetic field intensity. Plain Language Summary: Magnetic minerals in rocks can record and retain magnetic information for millions of years. This magnetic information helps us to understand processes like plate tectonics and geomagnetic field behavior in the past. When rocks experience compressional forces, these affect the magnetization of the magnetic minerals within them, potentially altering this magnetic information. Previous theoretical studies of the affect of stress on magnetization used analytical theory, and predicted that stresses of >1,000 MPa are required to alter a rock's otherwise stable magnetization. We show that much lower stresses of only ∼100 MPa are required to compromise magnetic recordings in rocks. The reason for this is a change in our understanding of rock magnetic systems. Previous analytical models were for elongated particles <100 nm in size, as these were thought to be the primary carriers of stable magnetization in minerals. We now know that larger particles can retain stable magnetic recordings to high temperatures over geological time. This study shows that the magnetization of these particles are less stable than smaller particles when stresses are applied. This suggests that common geological processes such earthquakes might provide sufficient near‐surface stress to remagnetize rocks close to the fault zone, leading to a paleo‐stress recording. Key Points: Single‐vortex particles' net magnetization rotates toward the compression axis when subjected to differential stressSingle‐vortex particles display the opposite response to compressional stress compared to single‐domain particlesStress fields of only ∼100 MPa are required to alter paleomagnetic signals, lower than previously predicted [ABSTRACT FROM AUTHOR]

Implementing high‐performance ultraviolet C photodetectors (UVC PDs) based on β‐Ga2O3 films is challenging owing to the anisotropic crystal symmetry between the epitaxial films and substrates. In this study, highly enhanced state‐of‐the‐art photoelectrical performance is achieved using single‐domain epitaxy of monoclinic β‐Ga2O3 films on a hexagonal sapphire substrate. Unlike 3D β‐Ga2O3 films with twin domains, 2D β‐Ga2O3 films exhibit a single domain with a smooth surface and low concentration of point defects, which enable efficient charge separation by suppressing boundary‐induced recombination. Furthermore, a tailored anti‐reflection coating (ARC) is adopted as a light‐absorbing medium to improve charge generation. The tailored nanostructure, which features a gradient refractive index, not only substantially reduces the reflection, but also suppresses the surface leakage current as a passivation layer. This study provides fundamental insights into the single‐domain epitaxy of β‐Ga2O3 films and the application of ARC for the development of high‐performance UVC PDs. [ABSTRACT FROM AUTHOR]

Substrate-binding proteins (SBPs) are key elements in determining the substrate specificity and high affinity of the ATP-binding cassette uptake system. A typical SBP has two domains that recognize substrates and are responsible for the specific substrate delivery. Conversely, in GenBank, genes for SBPs constituting a single domain SBP are often found in vicinity of a methyl-accepting chemotaxis protein gene. However, the molecular function and mechanism of single domain SBPs are not fully elucidated. To understand their molecular functions, we performed a crystallographic study of single domain SBP from Rhodothermus marinus (RmSBP). RmSBP crystals were soaked in solution containing NaBr or HgCl2 and their structures determined at 1.75 and 2.3 Å resolution, respectively. RmSBP soaked in NaBr exhibited disorder of the α2-helix, β5-to β6-strand loop, and C-terminus region, showing the structural dynamic region of RmSBP. RmSBP soaked in HgCl2 showed that Hg2+ bound to Cys145 located between the α5-and α6-helices. The structural properties of RmSBP were compared with those of single domain SBP homologs. These results will contribute to continued identification of the molecular function and mechanism of single domain SBPs.

Abstract In this study we use micromagnetic modeling to show that the magnetizations of magnetically single‐vortex particles rotate toward the stress axis on the application of a differential compression stress. This is the exact opposite response to magnetically single‐domain particles, which previously provided the theoretical underpinning of the effect of stress on the magnetic signals of rocks. We show that the magnetization directions of single‐vortex and equant single‐domain particles are altered by much lower stresses than previously predicted, c.f., 100 versus 1,000 MPa; where a change in magnetization is defined as a rotation of >3° after the removal of stress. The magnetization intensity of assemblages also drops by ∼20%–30% on the application and removal of stress of ∼100 MPa. Given that single‐vortex particles are now thought to dominate the magnetization of most rocks, future studies should account for paleomagnetic directional uncertainties and potential underestimation of the ancient magnetic field intensity.

The magnetic characteristics of fine sediment samples from the Solo Basin are reported in this paper. Magnetic fine sediment was identified by magnetic susceptibility mapping based on sampling of 182 points. Then, a depth analysis (on 7 selected sampling points) was performed using X-ray fluorescence spectrometry, which showed an iron oxide content of up to 55.42%, while X-ray diffractometry confirmed magnetite minerals with crystallite size ≤100 nm. Further, the vibrating sample magnetometry results verified the magnetic characteristics under a single-domain configuration. The characteristic magnetic susceptibility map showed that there is a lithogenic effect on sediment in the Solo Basin. In addition, anthropogenic activities seem to play a pivotal role in distributing magnetic materials.

The magnetic characteristics of fine sediment samples from the Solo Basin are reported in this paper. Magnetic fine sediment was identified by magnetic susceptibility mapping based on sampling of 182 points. Then, a depth analysis (on 7 selected sampling points) was performed using X-ray fluorescence spectrometry, which showed an iron oxide content of up to 55.42%, while X-ray diffractometry confirmed magnetite minerals with crystallite size =100 nm. Further, the vibrating sample magnetometry results verified the magnetic characteristics under a single-domain configuration. The characteristic magnetic susceptibility map showed that there is a lithogenic effect on sediment in the Solo Basin. In addition, anthropogenic activities seem to play a pivotal role in distributing magnetic materials. [ABSTRACT FROM AUTHOR]

Abstract We investigated temporal changes in the rock-magnetic properties of volcanic ash ejected from the Aso Nakadake volcano during a sequence of ash eruptions from 2019 to 2020. For 39 volcanic ash samples, magnetic hysteresis parameters, including saturation magnetization (M s), saturation remanent magnetization (M rs), coercivity (B c), and coercivity of remanence (B cr), were obtained. Curie temperature (T c) of the samples was also estimated using thermomagnetic analyses. Titanium-rich and -poor titanomagnetites were the dominant magnetic minerals in the volcanic ash, of which the titanium-rich phase was dominant. Systematic magnetic measurements of the volcanic ash ejected during the 1-year eruption event indicate that temporal changes in the hysteresis parameters occurred throughout the event. These temporal changes suggest that the M rs/M s and B c values of the volcanic ash increased considerably during several periods. The clear increases in M rs/M s and B c, associated with the central peak in FORC diagrams, indicate that non-interacting single-domain grains increased. For these high M rs/M s and B c samples, thermal demagnetizations of 3-axis IRM show that the low unblocking-temperature component up to 250–300 °C has apparently higher coercivity, suggesting that the above-mentioned, non-interacting single-domain grains are Ti-rich titanomagnetite. Interestingly, the high M rs/M s and B c values were synchronous with observations of volcanic glow. These results suggest that changes in the magnetic properties of titanomagnetite grains in volcanic ash reflect changes in physical conditions from the vent to the conduit of the volcano. Graphical Abstract

We investigated temporal changes in the rock-magnetic properties of volcanic ash ejected from the Aso Nakadake volcano during a sequence of ash eruptions from 2019 to 2020. For 39 volcanic ash samples, magnetic hysteresis parameters, including saturation magnetization (Ms), saturation remanent magnetization (Mrs), coercivity (Bc), and coercivity of remanence (Bcr), were obtained. Curie temperature (Tc) of the samples was also estimated using thermomagnetic analyses. Titanium-rich and -poor titanomagnetites were the dominant magnetic minerals in the volcanic ash, of which the titanium-rich phase was dominant. Systematic magnetic measurements of the volcanic ash ejected during the 1-year eruption event indicate that temporal changes in the hysteresis parameters occurred throughout the event. These temporal changes suggest that the Mrs/Ms and Bc values of the volcanic ash increased considerably during several periods. The clear increases in Mrs/Ms and Bc, associated with the central peak in FORC diagrams, indicate that non-interacting single-domain grains increased. For these high Mrs/Ms and Bc samples, thermal demagnetizations of 3-axis IRM show that the low unblocking-temperature component up to 250–300 °C has apparently higher coercivity, suggesting that the above-mentioned, non-interacting single-domain grains are Ti-rich titanomagnetite. Interestingly, the high Mrs/Ms and Bc values were synchronous with observations of volcanic glow. These results suggest that changes in the magnetic properties of titanomagnetite grains in volcanic ash reflect changes in physical conditions from the vent to the conduit of the volcano. [ABSTRACT FROM AUTHOR]

To satisfy the requirement of designing magnetic flexible composites, Co–Ti co-substituted M-type barium hexagonal ferrite nano powders with tunable magnetization have been successfully fabricated by a chemical coprecipitation plus molten salts method. The molten salts provide a liquid phase for phase formation and crystal growth of the targeted doped ferrite phases, leading to the formation of nano powders consisting of single domain particles with less agglomerations and particle size ranging from 60 to 100 nm. The co-doping of Co2+ and Ti4+ in the ferrites reduces their axial magnetic anisotropy, resulting in tunable magnetic properties from hard to soft magnetization. [Display omitted] [ABSTRACT FROM AUTHOR]

This work provides an effective approach to increase the magnetoelectric (ME) operating temperature of primordial sesqui oxide Cr2O3. The CoFe2O4 (core)/Cr2O3 (shell) nanoparticles with varying molar fractions are prepared via the sol-gel auto-combustion method. The phase-purity and coating induced micro-strains in core as well as shell have been validated from the Rietveld refinement of x-ray diffraction data, and are complementary to the Fourier transform infrared spectroscopy and Raman spectroscopy studies. Transmission electron microscopy measurement confirms the core/shell configuration of the nanoparticles. The magnetization measurements suggest screening of ferromagnetic interaction of CoFe2O4 (core) due to Cr2O3 shell over it, such that core/shell nanoparticles respond like single domain particles. A careful inspection of the impedance and modulus data suggest single relaxation in the studied frequency/temperature range for all the compositions. Both, the relaxation and the conduction processes are found to be polaronic obeying Mott variable range hopping mechanism. Direct ME measurements on these samples manifests the presence of linear magnetoelectricity for temperature as high as 400 K―a hallmark of enhancement in ME operating temperature of parental Cr2O3 phase and therefore widen its scope to meet the necessity of ME based potential applications. [ABSTRACT FROM AUTHOR]

In this work, we investigated the domain structure transition in ferromagnetic nanospheres at the ground-state conditions under zero external magnetic field by micromagnetic simulation. Four basic ferromagnetic materials, nickel (Ni), permalloy (Py), iron (Fe), and cobalt (Co), with variation in diameters from 20 to 100 nm were modeled in the simulation. It was observed that a transition of domain structure occurs from a single-domain to a multi-domain structure at a specific diameter based on the magnetization energy profile. Interestingly, a vortex–core orientation in the multi-domain regime was related to the magnetocrystalline axis of the material, which first aligns with the hard-axis direction, and then changes to the easy-axis direction for low-anisotropy materials (Ni, Py, and Fe). In contrast, only hard-axis orientation exists for high-anisotropy materials (Co). Furthermore, it is also observed that the transition of domain structure was related to the critical diameter. Below the critical diameter, a single-domain structure is exhibited in which the demagnetization energy was larger than the exchange energy. A multi-domain structure emerged above the critical diameter where the exchange energy was larger than the demagnetization energy. The comparable values of critical diameter were also calculated based on the Kittel and Brown equations. The results of the critical diameter from the micromagnetic simulation agreed with the theoretical calculations. Therefore, an interpretation of these magnetization dynamics is an important step in the material selection for granular magnetic-based storage.

Graphene epitaxy on the Si face of a SiC wafer offers monolayer graphene with unique crystal orientation at the wafer-scale. However, due to carrier scattering near vicinal steps and excess bilayer stripes, the size of electrically uniform domains is limited to the width of the terraces extending up to a few microns. Nevertheless, the origin of carrier scattering at the SiC vicinal steps has not been clarified so far. A layer-resolved graphene transfer (LRGT) technique enables exfoliation of the epitaxial graphene formed on SiC wafers and transfer to flat Si wafers, which prepares crystallographically single-crystalline monolayer graphene. Because the LRGT flattens the deformed graphene at the terrace edges and permits an access to the graphene formed at the side wall of vicinal steps, components that affect the mobility of graphene formed near the vicinal steps of SiC could be individually investigated. Here, we reveal that the graphene formed at the side walls of step edges is pristine, and scattering near the steps is mainly attributed by the deformation of graphene at step edges of vicinalized SiC while partially from stripes of bilayer graphene. This study suggests that the two-step LRGT can prepare electrically single-domain graphene at the wafer-scale by removing the major possible sources of electrical degradation.

With the gate-length scaling, the number of domains in FeFET is reduced to a few or a single domain. In this paper, we investigate the effect of multi-domains versus few/single-domain behavior in FeFET. The abrupt polarization switching behavior of a single-domain is obtained by modifying the Preisach model in which the difference between saturation and remnant polarization (P s− P r) is reduced. We show that for the same program/erase voltage, a two-times higher memory window can be achieved with single/few-domains FeFET than the multi-domain FeFET. Further, at fixed program/erase voltage, the scaling behavior shows improved variability due to increased polarization-induced vertical field with single-domain FeFET. We present an optimized device with a single-domain FeFET having a low operating voltage of ±2.4 V but with the same device performance that can be achieved for multi-domain FeFET having a higher operating voltage of ±5 V, which is highly promising for low power applications. [ABSTRACT FROM AUTHOR]

Background: Many patients with dementia with Lewy bodies (DLB) miss out on the best standards of care and psychosocial support due to diagnostic delays or inaccuracies following symptom onset.Objective: This study seeks to identify baseline characteristics in individuals with mild cognitive impairment (MCI) that correlate with eventual conversion to DLB or Alzheimer's disease (AD).Methods: Baseline neuropsychological and neuropsychiatric data were analyzed in National Alzheimer's Coordinating Center participants who completed the Uniform Data Set between 2006 and 2020 and subsequently converted from MCI to DLB or AD (n = 1632).Results: Only 6% of participants with MCI converted to DLB. Among those who converted to DLB, multidomain amnestic MCI (aMCI) was the most common subtype at study entry. As part of logistic regression analyses, odds ratios (ORs) were estimated for conversion to DLB versus AD based on study-entry characteristics, adjusting for age, sex, education, and years to diagnosis. The strongest predictors of conversion to DLB (p≤0.0001) were nonamnestic MCI versus aMCI (OR 8.2, CI [5.0, 14]), multidomain MCI versus single-domain MCI (OR 2.7, CI [1.7. 4.2]), male sex (OR 4.2, CI [2.5, 7.1]), and presence of nighttime behaviors (OR 4.4 CI [2.8, 6.9]).Conclusion: A diagnosis of prodromal DLB should be considered in individuals with MCI who present with prominent executive/visuospatial deficits, neuropsychiatric symptoms, and less memory impairment. Early diagnosis of DLB may guide treatment planning, including the avoidance of antipsychotic medications in patients who develop psychotic symptoms, caregiver support, and initiation of early treatment(s) once medications become available. [ABSTRACT FROM AUTHOR]

In this study, single-domain Ni x Co 1 − x Fe 2 O 4 ferrite nanoparticles with 0 ≤ x ≤ 1 were hydrothermally prepared and characterized using X-ray diffraction, transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), and vibrating sample magnetometry. According to the Rietveld refinement results, all of the prepared nanoparticles were single phase with spinel-type structures. Increasing the Ni content increased the average crystallite size and X-ray density while decreasing the lattice constant. According to the TEM observations, the nanoparticles were spherical in shape. The formation of a single-phase spinel structure with two lattices centered at tetrahedral and octahedral sites was confirmed by the observation of two absorption bands in all FT-IR spectra. Magnetization data showed that the prepared nanoparticles of all compositions were ferrimagnetic across the entire temperature range of 300 K to 10 K. Magnetic properties such as saturation magnetization, remanent magnetization, coercivity, magnetic anisotropy, and magnetic moments per unit cell were found to decrease with increasing Ni content. The big difference in H c of the x = 0, 0.25, 0.5, 0.75 ferrites between 300 K and 10 K suggested that these ferrite nanoparticles are truly single-domain nanoparticles. The small value of H c of the NiFe 2 O 4 (x = 1) ferrite and its very weak temperature dependence suggested that this sample is in a multi-domain regime. The ZFC–FC curves revealed the existence of spin-glass-like behavior in these ferrite nanoparticles over the entire temperature range. [ABSTRACT FROM AUTHOR]

The monomeric red fluorescent protein DsRed (mDsRed) is an optical probe widely used in multicolor applications in flow cytometry and fluorescence microscopy. Although the crystal structure of monomeric DsRed has been determined, its molecular dynamics have not been fully elucidated. To better understand its molecular flexibility, the crystal structure of mDsRed was recently determined, and its structure and temperature factors were analyzed. Solvent-accessible hole connected with the mDsRed chromophore was observed on the mDsRed surface structure. Electron density map analysis showed the tyrosine-ring group of the mDsRed chromophore in a cis -conformation, exhibiting flexibility with a nonplanar configuration between the tyrosine and imidazoline rings of the chromophore. Temperature factor analysis indicated that the top and bottom of the β-barrel are relatively flexible. These structural findings extended our understanding of the molecular flexibility of mDsRed. The detailed data collection and structure determination reported in this study can be used for future structural analyses., (© 2024 The Author. Published by Elsevier Inc.)

Substrate-binding proteins (SBPs) are essential in ATP-binding cassette transporter systems to determine substrate specificity and delivery. A typical SBP comprises two domains that recognize ligands such as metal ions, amino acids, sugars, and peptides. Interestingly, single-domain SBPs are found in the genomic database, but the molecular function of single-domain SBPs is not fully elucidated. To better understand the molecular function of single-domain SBPs, the crystal structure of single-domain SBPs from Rhodothermus marinus (RmSBP) soaked with NaBr and HgCl 2 were determined at 1.75 and 2.3 Å resolution, respectively. The molecular flexibility of RmSBP and Hg 2+ -bound RmSBP structure was determined. This structural information can be utilized to understand the molecular function of single-domain SBPs. This study reported the detailed process of data collection and structure determination., (© 2024 The Author. Published by Elsevier Inc.)

Fe and Co nano-whiskers and Co platelets were synthesized via physical vapor deposition without any template and catalyst. Transmission electron microscopic analyses revealed that the Fe whiskers were all single crystal with whisker axis along [1 0 0] crystallographic direction. Both FCC and HCP crystal structures were found in the Co whiskers with stacking faults and micro-twins. Off-axis Electron holography results showed that all the whiskers synthesized were magnetic single domain structures. Vortex state was observed in a small platelet of high symmetry.

In this work, we investigated the domain structure transition in ferromagnetic nanospheres at the ground-state conditions under zero external magnetic field by micromagnetic simulation. Four basic ferromagnetic materials, nickel (Ni), permalloy (Py), iron (Fe), and cobalt (Co), with variation in diameters from 20 to 100 nm were modeled in the simulation. It was observed that a transition of domain structure occurs from a single-domain to a multi-domain structure at a specific diameter based on the magnetization energy profile. Interestingly, a vortex-core orientation in the multi-domain regime was related to the magnetocrystalline axis of the material, which first aligns with the hard-axis direction, and then changes to the easy-axis direction for low-anisotropy materials (Ni, Py, and Fe). In contrast, only hard-axis orientation exists for highanisotropy materials (Co). Furthermore, it is also observed that the transition of domain structure was related to the critical diameter. Below the critical diameter, a single-domain structure is exhibited in which the demagnetization energy was larger than the exchange energy. A multidomain structure emerged above the critical diameter where the exchange energy was larger than the demagnetization energy. The comparable values of critical diameter were also calculated based on the Kittel and Brown equations. The results of the critical diameter from the micromagnetic simulation agreed with the theoretical calculations. Therefore, an interpretation of these magnetization dynamics is an important step in the material selection for granular magnetic-based storage. [ABSTRACT FROM AUTHOR]

• Fe- doped Barium Titanate is prepared by solid state reaction route and found in tetragonal phase. • Photoluminescence spectroscopy was used to identify oxygen vacancies. • Positron Annihilation spectroscopy did not detect Ba and Ti vacancies. • Hyperfine parameters for the obtained sextet patterns in Mössbauer spectra for ferromagnetic and antiferromagnetic interactions were calculated. • Single domain non-superparamagnetic state was achieved by progressive grain refinement. A systematic study on the magnetic properties of the BaTi 1-x Fe x O 3-δ (x = 0.02) system with decrease in grain sizes is presented. The combined study of long range and short range magnetic orderings together was carried out. The samples were prepared in single tetragonal phase. The grains of the pristine sample were refined from micron to nanometer range by mechanical milling. Oxygen vacancies in different charge states gave rise to ferromagnetic and antiferromagnetic orderings among the Fe3+ ions whereas oxygen atoms acted as the medium for antiferromagnetic superexchange among the Fe3+ ions. Magnetization was found to increase significantly as a result of milling and eventually the saturation magnetization became four-fold in the sample with grain size around 18 nm. The increase in magnetization is attributed to the increase in oxygen vacancies as a consequence of increase in milling time. Clear sextet patterns in the Mössbauer spectra were observed in the sample wherein 57Fe–enriched iron was used in place of natural iron. These sextets were attributed to the presence of FM and AFM orderings among Fe3+ ions. Along with the sextet patters, we also observed a doublet pattern in Mössbauer spectra because of quadrupolar interaction of the isolated Fe3+ ions arranged in non-cubic environment and lacking any kind of magnetic interactions among them. Mössbauer Spectroscopic (MS) study revealed that FM ordering increased while AFM ordering disappeared after milling. Drastic fall of coercivity in samples with grain sizes below around 40 nm indicated that they became single magnetic domain. [ABSTRACT FROM AUTHOR]

In this study, single-domain NixCo1−xFe2O4 ferrite nanoparticles with 0≤x≤1 were hydrothermally prepared and characterized using X-ray diffraction, transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), and vibrating sample magnetometry. According to the Rietveld refinement results, all of the prepared nanoparticles were single phase with spinel-type structures. Increasing the Ni content increased the average crystallite size and X-ray density while decreasing the lattice constant. According to the TEM observations, the nanoparticles were spherical in shape. The formation of a single-phase spinel structure with two lattices centered at tetrahedral and octahedral sites was confirmed by the observation of two absorption bands in all FT-IR spectra. Magnetization data showed that the prepared nanoparticles of all compositions were ferrimagnetic across the entire temperature range of 300 K to 10 K. Magnetic properties such as saturation magnetization, remanent magnetization, coercivity, magnetic anisotropy, and magnetic moments per unit cell were found to decrease with increasing Ni content. The big difference in Hc of the x = 0, 0.25, 0.5, 0.75 ferrites between 300 K and 10 K suggested that these ferrite nanoparticles are truly single-domain nanoparticles. The small value of Hc of the NiFe2O4(x=1) ferrite and its very weak temperature dependence suggested that this sample is in a multi-domain regime. The ZFC–FC curves revealed the existence of spin-glass-like behavior in these ferrite nanoparticles over the entire temperature range.

Anisotropy of Magnetic Susceptibility (AMS) is a valid tool to investigate magma flow direction within dikes. However, geometrically inverse magnetic fabric characterized by maximum magnetic susceptibility axis (kmax) perpendicular to the dike wall may complicate the interpretation of flow trajectories. To better understand the nature of this fabric, we present a multiscale study on 19 dikes (383 samples) in the Miocene Alftafjordur volcanic system (Iceland), where 80% of the samples show a geometrically inverse magnetic fabric. We carried out (1) AMS measurements at different magnetic fields and temperatures, along with Anisotropy of Anhysteretic Remanent Magnetization (AARM) analysis; (2) hysteresis loops and FORC diagrams; (3) thin section analysis; (4) structural fieldwork. A variable Ti‐content (0.1 < x < 0.6, Fe3‐xTixO4) titanomagnetite is the main magnetic carrier, and the contribution of the paramagnetic elongated crystals to the magnetic fabric is negligible. Single domain is not the prevailing domain state of the magnetic particles, suggesting that its occurrence cannot be the main cause for the inverse fabric. AMS analysis at different fields and temperatures along with AARM allow us to exclude any mineral phase change of the titanomagnetite across the dike. Nevertheless, kmax is parallel to a diffuse horizontal column‐like fracture pattern perpendicularly oriented with respect to the dike strike. This suggests that the Ti‐magnetite mineral orientation during dike cooling was affected by the fracture network progressively developing columnar basalts. This study demonstrates that the interpretation of AMS data on old and deep volcanic bodies is not straightforward and observations at different scales are required. Key Points: Our analyses about the magnetic fabric of the Alftafjordur dike swarm revealed that most of the samples show an inverse magnetic fabricThe origin of the inverse magnetic fabric is associated with the development of horizontal fractures during the cooling stage of dikesIt is not straightforward to infer the magma flow direction on deep and old exhumed dikes by using standard low‐field AMS measurements only [ABSTRACT FROM AUTHOR]

Cobalt-doped zinc sulfide quantum dots with different cobalt concentrations were prepared by the solution route. Structural, optical, morphological, and magnetic responses of the prepared quantum dots were analyzed. X-ray diffraction study confirmed that cubic (zinc blende) structure is the dominant structure of synthesized samples. Crystallite size and lattice constant were found to decrease with cobalt dopant. Transmission electron microscope analysis shows that the mean size of the particles lies in the range of 7–10 nm. The absorption edge of cobalt-doped zinc sulfide nanoparticles is shifted to lower wavelength as compared to that of bulk zinc sulfide which confirmed the quantum confinement effect. The bandgap variation was observed with doping, and it varied from 4.3 to 5.6 eV. The emission spectrum reveals that the cobalt dopant suppresses the ultraviolet emission and enhances the visible emission. Fourier-transform infrared spectrum confirmed the formation of zinc sulfide and the substitution of cobalt ion. Magnetization versus magnetic field result demonstrates that the zinc sulfide and cobalt-doped zinc sulfides are superparamagnetic. Electron spin resonance spectra also confirmed the superparamagnetic nature of zinc sulfide and cobalt-doped zinc sulfide samples. Micro-Raman study also confirmed the incorporation of cobalt in the lattice and the size of the order of the exciton Bohr radius for ZnS. [ABSTRACT FROM AUTHOR]

Inorganic luminescent materials based on photoluminescence (PL) and thermoluminescence (TL) display considerable potential applications for optical anti‐counterfeiting devices. Ca2−xNb2O7:xPr3+ (x = 0.00075, 0.001, 0.002, 0.003, 0.004) ferroelectric ceramics have been fabricated. The basic crystal structure, local ferroelectricity and PL/TL properties of the ceramics have been investigated in this study. The PFM measurement proves that the grains in the prepared ceramics are monodomain state. Furthermore, the synthesized phosphors are embedded into polydimethylsiloxane (PDMS) matrix to fabricate a novel optothermal responsive device with high elasticity, transmittance and heat resistance. The PL and TL photographs of the designed device further demonstrate that the device is promising in practical applications such as optical anti‐counterfeiting and information storage. [ABSTRACT FROM AUTHOR]

The purpose of the review is to analyze and summarize the results of the works performed at Chuiko Institute of Surface Chemistry of NAS of Ukraine, dedicated to the synthesis and study of the properties of new magnetic fluids (MF) containing NC of superparamagnetic core – multilevel shell type and characterized by the functions of medicobiologic nanorobots. The research themes are focused on the creation of the latest medical theranostic remedies for targeted delivery and local complex treatment, primarily for needs of oncology. The methodology of the work includes formulation of the problem of synthesis of NC of superparamagnetic coremultilevel shell type with the functions of biomedical nanorobots, relative MF, comprehensive studies of magnetic, structural and rheological characteristics, sedimentation stability, antitumor activity in vitro, in vivo. It has been shown that calculations of the magnetization curve of MF based on single-domain superparamagnetic Fe3O4, within the framework of Langevin’s theory of paramagnetism, are satisfactorily coordinated with the experimental results, assuming that the saturation magnetization of magnetite particles depends on their size. On the basis of the obtained data, the idea has been formulated of using an ensemble of magnetic fluid nanoparticles as a superparamagnetic probe to diagnose its parameters and to substantiate the development of the magnetic granulometry method and the possibility of its application to measure the size parameters of a complex shell structure of magnetically sensitive nanocomposites of superparamagnetic core – multilevel shell type. The obtained data develop the physicochemical basis for the development of new types of vector systems of anticancer drugs based on MF and have been used to improve the method of magnetic granulometry in order to optimize, standardize and control their parameters in the production process. In particular, the synthesized MF and the approaches to their magnetic diagnostics given in this work have been used in the creation of a new native oncological remedy “Feroplat” that has no analogues in the world, is a conjugate of nanoparticles of MF with cisplatin, is a standardized remedy for enhancement of the effectiveness of chemotherapy and overcoming of drug resistance of malignant neoplasms, designed to deliver cytostatic agent directly to the tumor tissue, ensuring maximal its entrance into cells and favoring an increase in the therapeutic effect. In order to be introduced into the production and clinical practice, feroplat is on a stage of completion of preclinical testing. The data are given on the cytotoxic properties and biological safety of MF containing cisplatin. It has been shown that on the general and biochemical parameters of the blood, the use of MF does not make a more toxic influence on the body, compared with the antitumor drug cisplatin in equivalent doses. The technological scheme is presented for manufacturing of a new magnetocarried polyfunctional antitumor vector system based on MF containing drugs in the structure of core-shell type nanocomposites. The results of the work are used also in the development of new magnetocarried adsorption materials for technical, technological, ecological and biomedical purposes, in the educational process of native universities in training of bachelors and masters of the corresponding specialties. [ABSTRACT FROM AUTHOR]

• Overall magnetic properties depend on phase evolution. • Average particle size increased with increasing annealing temperature. • Transition from single-domain to multi-domain configuration with annealing. • Incoherent magnetization reversal mechanism in single domain Ba 1-x Sr x Fe 12 O 19. The correlation of phase evolution (annealing at different temperatures) with magnetic properties like magnetization reversal, coercivity mechanism, and energy product in M-type hexaferrite by substituting Sr in place of Ba has been reported in the present article. The Ba 1-x Sr x Fe 12 O 19 (x = 0.0, 0.5, & 1.0) have been prepared by the sol–gel auto-combustion method followed by annealing at different temperatures from 800 °C to 1200 °C. The structural and magnetic properties have been characterized by X-ray diffraction, Field emission scanning electron microscopy, Raman spectroscopy, and Vibrating sample magnetometer. The Rietveld refinement confirms contraction in unit cell parameters by replacing Sr in place of Ba and lattice expansion with increasing annealing temperature. There is no significant effect of substitution on magnetic properties found rather heat treatment affects greatly. The transition from a single domain to multidomain particles and their contribution to initial magnetization curves are analyzed. The differential susceptibility (dM/dH) calculated from room temperature magnetization confirms the existence of a pinning effect during magnetization reversal for samples heat treated below 1200 °C. Secondary phases or grain boundaries are believed to act like pinning centers. This work opens insight into the domain wall motion by microstructure engineering. The coercivity is tuned to 6.09 kOe by controlling the annealing temperature for the Ba 1-x Sr x Fe 12 O 19 (x = 1.0) sample. The maximum energy product (BH) max in the range of 0.94–1.27 MGOe has been achieved. [ABSTRACT FROM AUTHOR]

Magnetic hyperthermia is an effective modality for treating cancerous cells selectively at the intracellular level via proper administration, surface tagging and appropriate choice of magnetic nanoparticle. Also, achieving the therapeutic temperature with as much low concentration of nanoparticles, as possible, is desirable. Recently, ferromagnetic nanoparticles or ferrofluid are gaining attention as effective magnetic hyperthermia agents due to their enhanced heating potential under in vivo conditions. In the present work, we have fabricated citrate capped cobalt ferrite ferrofluid via a simple two-step process and investigated the physicochemical, magnetic and induction heating performance. The average size of the synthesized nanoparticle is 9 ± 4.3 nm which is suitable for intracellular hyperthermia and has the advantage that it can be easily eliminated from the body through renal clearance. The M (T) measurement of the ferrofluid confirmed the soft ferromagnetic behavior. The induction heating potential of the ferrofluid prepared was tested at different concentrations (1, 2, 5 & 10 mg/ml), suspension medium and alternating magnetic fields (15, 30 & 45 kA/m) with a fixed frequency of 316 kHz. Under a viscous environment, 1 mg/ml sample subjected to 45 kA/m reached the hyperthermia temperature within 160 s and the specific loss power was found to be 297 W/g (Co+Fe). Hence, the synthesized ferrofluid is suitable for intratumoural hyperthermia. [Display omitted] • We have successfully fabricated citrate capped hydrophilic CoFe 2 O 4 ferrofluid with a simple two-step process. • Even at a small size (9 ± 4.3 nm) soft ferromagnetic behaviour was observed. • 1 mg/ml (f = 316 kHz and H 0 = 45 kA/m) ferrofluid reached hyperthermia temperature within 160 s in viscous medium. • Synthesized ferrofluid is suitable for intratumoural hyperthermia. [ABSTRACT FROM AUTHOR]

Mild cognitive impairment (MCI) patients have a high risk of converting to Alzheimer's disease. The most common diagnostic subtypes of MCI have an episodic memory disorder (amnestic MCI) occurring either alone [single domain (SD)] or with other cognitive impairments [multiple domain (MD)]. Previous studies report increased amplitudes of auditory cortical potentials in MCI, but their relationships to MCI subtypes and clinical outcomes were not defined. We studied subjects with amnestic MCI (n = 41: 28 SD, 13 MD), Alzheimer's disease (n = 14), and both younger (n = 22) and age-matched older controls (n = 44). Baseline auditory sensory (P50, N100) and cognitive potentials (P300) were recorded during an auditory discrimination task. MCI patients were followed for up to 5 years, and outcomes were classified as (i) continued diagnosis of MCI (MCI-stable, n = 16), (ii) probable Alzheimer's disease (MCI-convert, n = 18), or other outcomes (n = 7). Auditory potentials were analysed as a function of MCI diagnosis and outcomes, and compared with young, older controls, and mild Alzheimer's disease subjects. P50 amplitude increased with normal ageing, and had additional increases in MCI as a function of both initial diagnosis (MD > than SD) and outcome (MCI-convert > MCI-stable). P300 latency increased with normal ageing, and had additional increases in MCI but did not differ among outcomes. We conclude that auditory cortical sensory potentials differ among amnestic MCI subtypes and outcomes occurring up to 5 years later.

Implementing high-performance ultraviolet C photodetectors (UVC PDs) based on β-Ga 2 O 3 films is challenging owing to the anisotropic crystal symmetry between the epitaxial films and substrates. In this study, highly enhanced state-of-the-art photoelectrical performance is achieved using single-domain epitaxy of monoclinic β-Ga 2 O 3 films on a hexagonal sapphire substrate. Unlike 3D β-Ga 2 O 3 films with twin domains, 2D β-Ga 2 O 3 films exhibit a single domain with a smooth surface and low concentration of point defects, which enable efficient charge separation by suppressing boundary-induced recombination. Furthermore, a tailored anti-reflection coating (ARC) is adopted as a light-absorbing medium to improve charge generation. The tailored nanostructure, which features a gradient refractive index, not only substantially reduces the reflection, but also suppresses the surface leakage current as a passivation layer. This study provides fundamental insights into the single-domain epitaxy of β-Ga 2 O 3 films and the application of ARC for the development of high-performance UVC PDs., (© 2023 Wiley-VCH GmbH.)

Cobalt-zinc ferrite nanoparticles having composition Co 1-x Zn x Fe 2 O 4 were processed by sol-gel method with particle sizes ranging from 10.8 nm to 3.6 nm. The crystal structure, particle size, and magnetic properties were investigated by XRD, FTIR, TEM, and VSM techniques. Single domain nature was established from the coercivity versus particle size curve. The dependence of specific saturation magnetization with zinc concentration was discussed in terms of site occupancy of cations and supported by FTIR measurements. A few single domain nanoparticle compositions exhibiting low Curie temperatures and reasonably good magnetization were subjected to induction heating measurement to explore the possibility of using the materials for magnetic hyperthermia. The material, having the composition, Co 0.37 Zn 0.63 Fe 2 O 4 was shown to be an excellent candidate for conducting hyperthermia study with self-regulated temperature at 46 °C. • Nanoparticles of size from 3.6 nm to 10.8 nm were synthesized by sol-gel method. • The chelating agent, polyvinyl alcohol was found to be powerful in controlling the particle size. • The transition from multi-domain to single domain nanoparticle was established with zinc concentration. • The composition Co 0.37 Zn 0.63 Fe 2 O 4 was developed with Curie temperature, 46 °C. • Self regulated magnetic hyperthermia in the composition, Co 0.37 Zn 0.63 Fe 2 O 4 was achieved. [ABSTRACT FROM AUTHOR]

The Day diagram is used extensively in rock magnetism for domain state diagnosis. It has been shown recently to be fundamentally ambiguous for 10 sets of reasons. This ambiguity highlights the urgency for adopting suitable alternative approaches to identify the domain state of magnetic mineral components in rock magnetic studies. We evaluate 10 potential alternative approaches here and conclude that four have value for identifying data trends, but, like the Day diagram, they are affected by use of bulk parameters that compromise domain state diagnosis in complex samples. Three approaches based on remanence curve and hysteresis loop unmixing, when supervised by independent data to avoid nonuniqueness of solutions, provide valuable component‐specific information that can be linked by inference to domain state. Three further approaches based on first‐order reversal curve diagrams provide direct domain state diagnosis with varying effectiveness. Environmentally important high‐coercivity hematite and goethite are represented with variable effectiveness in the evaluated candidate approaches. These minerals occur predominantly in noninteracting single‐domain particle assemblages in paleomagnetic contexts, so domain state diagnosis is more critical for ferrimagnetic minerals. Treating the high‐coercivity component separately following normal rock magnetic procedures allows focus on the more vexing problem of diagnosing domain state in ferrimagnetic mineral assemblages. We suggest a move away from nondiagnostic methods based on bulk parameters and adoption of approaches that provide unambiguous component‐specific domain state identification, among which various first‐order reversal curve‐based approaches provide diagnostic information. Key Points: We assess 10 alternative approaches for domain state diagnosis as potential replacements for the much used but ambiguous Day diagramWe recommend adoption of methods that enable domain state identification of each component in samples with complex magnetic mineral mixturesWe conclude that magnetization curve analysis and FORCs provide the most diagnostic component‐specific domain state identifications [ABSTRACT FROM AUTHOR]

Substrate-binding proteins (SBPs) are key elements in determining the substrate specificity and high affinity of the ATP-binding cassette uptake system. A typical SBP has two domains that recognize substrates and are responsible for the specific substrate delivery. Conversely, in GenBank, genes for SBPs constituting a single domain SBP are often found in vicinity of a methyl-accepting chemotaxis protein gene. However, the molecular function and mechanism of single domain SBPs are not fully elucidated. To understand their molecular functions, we performed a crystallographic study of single domain SBP from Rhodothermus marinus (RmSBP). RmSBP crystals were soaked in solution containing NaBr or HgCl 2 and their structures determined at 1.75 and 2.3 Å resolution, respectively. RmSBP soaked in NaBr exhibited disorder of the α2-helix, β5-to β6-strand loop, and C-terminus region, showing the structural dynamic region of RmSBP. RmSBP soaked in HgCl 2 showed that Hg 2+ bound to Cys145 located between the α5-and α6-helices. The structural properties of RmSBP were compared with those of single domain SBP homologs. These results will contribute to continued identification of the molecular function and mechanism of single domain SBPs., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 The Author. Published by Elsevier B.V.)

Nonlayered two-dimensional (2D) magnets have attracted special attention, as many of them possess magnetic order above room temperature and enhanced chemical stability compared to most existing vdW magnets, which offers remarkable opportunities for developing compact spintronic devices. However, the growth of these materials is quite challenging due to the inherent three-dimensionally bonded nature, which hampers the study of their magnetism. Here, we demonstrate the controllable growth of air-stable pure γ-Fe 2 O 3 nanoflakes by a confined-vdW epitaxial approach. The lateral size of the nanoflakes could be adjusted from hundreds of nanometers to tens of micrometers by precisely controlling the annealing time. Interestingly, a lateral-size-dependent magnetic domain configuration was observed. As the sizes continuously increase, the magnetic domain evolves from single domain to vortex and finally to multidomain. This work provides guidance for the controllable synthesis of 2D inverse spinel-type crystals and expands the range of magnetic vortex materials into magnetic semiconductors.

The alkaline-earth metal adsorption on Si(0 0 1) has attracted much interest for finding a proper template in the growth of high- κ and crystalline films. Up to now on the flat Si(0 0 1) surface with double domains and single-layer steps, the adsorbed Ba atoms are known to induce the 2 × 3 structure through removing two Si dimers and adding a Ba atom per unit cell in each domain. In the present investigation, the Si(0 0 1)-4° off surface with D B steps and single domains has been employed as a substrate and the reconstruction at the initial stage of Ba adsorption has been investigated by scanning tunneling microscopy and synchrotron photoemission spectroscopy. On this vicinal and single domain terrace, a novel 3 × 2 structure rotated by 90° from the 2 × 3 structure has been found. Such a 3 × 2 structure turns out to be formed by adding a Ba atom and a Si dimer per unit cell. This results from the fact that the adsorbed Ba 2+ ions with a larger ionic radius relieve tensile stress on the original Si dimers exerted by the rebonded atoms at the D B step. [ABSTRACT FROM AUTHOR]

Ba and Ta co-doped bismuth ferrites with the composition Bi 0.8 Ba 0.2 Fe 1-x Ta x O 3 (where x = 0, 0.05, 0.10 and 0.15) were synthesized employing a solid state reaction method. Rietveld refinement of XRD patterns revealed that Ba doping caused structural transformation in perovskite BFO from rhombohedral ( R 3 c ) to tetragonal ( P 4 mm ) with up to 10% Ta doping. However, with 15% Ta substitution (BBFTO-15) the ceramics exhibited a mixture of tetragonal and rhombohedral structures. Curve fitting of room temperature magnetization vs. magnetic field data showed that the shape of the hysteresis loops for these ceramics were the result of coexistence of single domain and superparamagnetic contributions. For 10% Ta substitution (BBFTO-10), the contribution from superparamagnetic particles was dominant. Polarization with respect to electric field measurements did not yield typical hysteresis loops; instead evidence of high leakage was present in BBFTO-0 and BBFTO-5 while that of BBFTO-10 and BBFTO-15 exhibited a lossy dielectric nature. The I-V characteristics confirmed that Ta doping reduced the leakage current by greater than two orders of magnitude compared to BBFTO-0. It is believed that the reduction in oxygen vacancy in the doped samples was key in reducing the leakage current. As a matter of fact, XPS data revealed a reduction in oxygen vacancy concentration and the percentage of Fe 3+ was also found to increase with increasing Ta doping. Dielectric constant and dielectric loss were also found to decrease with the increase of Ta doping. Impedance spectroscopy confirmed the contribution from multiple impedance components including evidence of a dipolar relaxation that was found in BBFTO-5 and BBFTO-10. Defect associates were proposed to be responsible for such relaxations. [ABSTRACT FROM AUTHOR]