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The application of optimal electron count has proven effective in predicting the existence of complex structural topologies containing electron-rich polyanionic networks, including linear and zig-zag chains, square planar structures, and simple cubic lattices of main group elements. In this study, we report the successful synthesis of a new family of magnetic compounds, RSe2−x (x ∼ 1/6) (R = Gd and Tb), using KCl flux. The resulting crystal structure of RSe2−x is tetragonal, exhibiting PbFCl-type symmetry with space group P4/nmm. Chemical composition analysis consistently reveals x ∼ 1/6, indicating chalcogen-deficient square sheets. This observation suggests that RSe2−x adheres to the 14-electron rule, as the total valence electrons per RSe2−x (x ∼ 1/6) is 14 e−. In GdSe2−x (x ∼ 1/6), the magnetic susceptibility measurement displays a lambda-shaped peak around 8 K, indicating an antiferromagnetic-type transition. However, the positive Curie–Weiss temperature (θCW) suggests the presence of an additional ferromagnetic interaction, which may result from the large magnetic moment of the Gd atoms. In contrast, TbSe2−x (x ∼ 1/6) exhibits antiferromagnetic ordering. Chemical bonding analysis also indicates that the strong Se–Se antibonding in the square net may be related to Se deficiency. Our work shed light on ellucidating the interplay between chemical rule, defects, and magnetism. [ABSTRACT FROM AUTHOR]

This paper describes the hydrodynamic behavior of superparamagnetic iron oxide nanoparticles modified with citric acid (CA-SPIONs) in suspension under alternating current magnetic fields given interparticle and inter-cluster dipole–dipole interactions. The cluster size of the CA-SPIONs is modulated to control interparticle interactions, and the ionic concentration of the CA-SPION suspension is varied to control inter-cluster interactions. Dynamic magnetic susceptibility (DMS) measurements of the CA-SPION suspensions under alternating current magnetic fields indicate that the interparticle interaction by clustering and the inter-cluster interaction by increasing the ionic concentration cause frequency spectra modulation, such as their broadening in the low-frequency region and a decrease in the Brownian relaxation frequency. The experimentally obtained DMS spectra differ from the spectra numerically calculated from the hydrodynamic size distribution of CA-SPIONs using the Debye relaxation model without considering the magnetic interactions; the differences are attributed to the interparticle and inter-cluster dipole–dipole interactions. These insights contribute to a deeper understanding of dynamics of superparamagnetic iron oxide nanoparticles and facilitate nanoparticle parameter optimization for tailored applications in the biomedical field, particularly for their efficacy and precision in liquid-phase biosensing and imaging. [ABSTRACT FROM AUTHOR]

In this paper, the effects of hydrostatic stress on the magnetic properties of Mn-Zn power ferrites are discussed. Ring cores were embedded in cement and the curing process gradually exerted pressure on the core. A novel testing method was developed to continuously measure the power losses and the magnetic susceptibility in dependence on magnetic excitation at a fixed frequency and room temperature with a vector network analyzer. After 450 h, a maximum compressive stress of 120 MPa was reached. Power loss up to 300% was observed, while magnetic susceptibility dropped by 35%. The magneto-mechanical effect on core losses was simulated with the Hodgdon–Esguerra hysteresis model, showing excellent agreement with tested results, which allows us to predict the behavior of ferrite tiles embedded in load-bearing surfaces for wireless power transfer (WPT) applications. [ABSTRACT FROM AUTHOR]

When a diamagnetic graphite plate is placed on top of a magnet, it is subject to both magnetic levitation and gravitational forces. Computational modeling is used to demonstrate that these forces can balance each other to allow a stable tilt angle θ to be attained when the graphite plate pivots on the magnet surface. θ depends on the magnetic susceptibility χmag, which can be controlled by using laser irradiation to change the temperature of the graphite. Over a limited temperature range, there is a linear relation between the angle change Δθ and the temperature change ΔT. This predicted behavior is confirmed experimentally using a graphite plate (5 × 5 × 0.83 mm) placed on top of a 7.5 cm diameter neodymium iron boride magnet with a surface field strength of ∼5000 G. Using a 532 nm laser, θ could be continuously tuned from 52° to 26° by varying the laser power between 20 and 800 mW. The response time was about 15 s at all powers. Higher laser powers were observed to lead to a complete loss of levitation, followed by recovery and oscillation in and out of the laser beam. The linear dependence of Δθ on power suggests that photothermal tilting of the graphite plate in a magnetic field provides a fatigue resistant way to achieve large angular deviations using an external light source. This effect can be harnessed to function as a laser-controlled beam steering device. [ABSTRACT FROM AUTHOR]

Understanding the magnetic states and their dynamics in patterned ferromagnetic materials is of great importance for ultrahigh-density recording from the viewpoints of both fundamental research and practical applications. However, reliable access to magnetization dynamics in magnetic materials and devices on the technologically highly relevant terahertz range remains challenging. Currently, there is a lack of reports on terahertz magnetic susceptibility. Here, through micromagnetic simulations, we study the dynamics of pyramid-shaped, isolated magnetic nanodots and their arrays made of L10-FePt with high magnetocrystalline anisotropy. Numerical results reveal a significant magnetic response of isolated pyramid nanodots in the terahertz range. Specifically, two resonant modes, namely, a bulk mode and an edge mode, have been identified. For the lateral size above ∼100 nm, the nanodot's bulk mode splits and higher-order modes appear. Furthermore, the calculated spatial Fourier amplitude of resonant modes of nanopyramid arrays exhibits the dependence of lateral size and inter-dot spacing. These findings are expected to open up a promising route to terahertz spintronics utilizing magnetic nanostructures. [ABSTRACT FROM AUTHOR]

The studies on hydrothermal alteration-induced effects in surface and subsurface rocks provide useful information in the characterization and exploitation of a geothermal reservoir. Generally, these studies are based on traditional, and reliable methods like petrography (primary and secondary minerals, and grade of alteration), and geochemistry (mobility of elements, changes in mass and concentration of elements, and fluid inclusions). Recently, apart from these established methods, some methods based on the geochemical (Chemical Index of Alteration, CIA; Weathering Index of Parkar, WIP; Loss on Ignition, LOI; and Sulfur, S) and rock magnetic properties (magnetic susceptibility, χlf; and percentage frequency-dependent susceptibility, χfd%) are also being applied in the identification of whether a rock is an altered or a fresh one. The Acoculco Geothermal Field (AGF), Mexico, is characterized by high temperature and very low permeability, and it is considered a promissory Enhanced Geothermal System. The following changes are observed in the rocks as a result of an increase in hydrothermal alteration: (1) an increase in CIA, LOI, and S values, and a decrease in WIP; (2) an increase in quartz and quartz polymorph minerals (silicification), and clay minerals (argillization); and (3) decrease in χlf values. At AGF, the most altered surface acid rocks are characterized by entirely quartz and its polymorphs, and clay minerals. The present study also indicates the applicability of the binary plots of major elements (felsic vs mafic component) and rock magnetic parameters (χlf vs. χfd%). The rock with χfd% value of 2–10 and χlf value < 0.5 × 10–6 m3 kg−1 indicate the presence of single domain and stable single domain grains, which in turn suggests that it is an altered rock. These methods are simple to apply, rapid, reliable, and have the potential to become effective tools for the identification of hydrothermally altered rocks during the initial stage of geothermal exploration. [ABSTRACT FROM AUTHOR]

Nano‐sized bivalent metal complexes, specifically [M(L)2] with L = 2‐((E)‐((4,5‐dimethyl‐2‐(((E)‐4‐methylbenzylidene)amino)phenyl)‐imino)methyl)benzenethiol] (C23H22N2S) and M = Cu (II) (C1), Co (II) (C2), Ni (II) (C3), and Zn (II) (C4), underwent synthesis and subsequent characterization. Elemental analyses, infrared, NMR, mass, electronic, magnetic susceptibility, conductivity assessments, and X‐ray diffraction studies were used to assess our bivalent metal complexes. DFT studies were used to study the tautomeric equilibrium of the tridentate thio‐Schiff base ligand (HL), via the DFT\B3LYP method in connection with a 6–311G* correlation consistent basis set. Two tautomers, which are thione and thiol forms, were studied to estimate the predominant one. The metal formed four coordinated with the tridentate N2S donor thio‐Schiff base to form octahedral geometry complexes. The SEM, TEM, XRD, AFM, and EDX of the studied complexes unveiled distinct and strong diffraction peaks, signifying their crystalline nature and providing evidence of their particle sizes being within the nano‐size. The crystal sizes calculated for all complexes were determined to be ranging from 27.73 to 76.39 nm. The interactions between metal complexes and calf thymus DNA, and their potential for mimicking insulin activity, were investigated in a controlled lab setting by measuring their ability to inhibit alpha‐amylase. The antimicrobial potential of thio‐Schiff base ligand (HL) plus complexes (C1–C4) were tested. The viscosity and UV–Vis absorption determinations were utilized to assess the calf thymus DNA (CT‐DNA) interaction with the nano‐sized metal (II) chelates. Our flow cytometry data indicate significant levels of apoptosis and cell cycle arresting in both liver and breast cancer cell lines. [ABSTRACT FROM AUTHOR]

In the present study, conformations and aromaticity of seventeen [13], [23] and [33] double-stranded cyclophanes composed of three benzene moieties were investigated at B3LYP level of density functional theory. The stability of these conformers is different depending on the type of cycloalkane-like cycles formed by (CH2) n bridges and the peripheral benzene rings, and also the curvature of the latter. In [13] cyclophane, this leads to only one conformer containing puckered cyclobutane-like cycle, at an angle of about 37◦. In comparison, in cyclophanes [23] and [33], the corresponding cycles are cyclohexane-like and cyclooctane-like, respectively. While conformer 2a having TB-like cycles is the most stable member of the [23] family, of eight ground-state conformers obtained for [33], 3a with two Chair-Chair-like and one Twist-Chair-like cycles is the most stable one, and 3h with three Twist-Boat-like cycles being 6.5 kcal higher in energy than the former is the least stable member of series. In addition to the conformational analysis, the aromaticity of the series has been assessed using different indexes, including magnetic criteria nucleus-independent chemical shifts (NICS-based) at the cage and at the ring centers, HNMR chemical shift, Magnetic Susceptibility, HOMA and relative energy (RE). [ABSTRACT FROM AUTHOR]

We synthesized La2NiO4 nanostructures using the cationic surfactant-based reverse micellar route and reported on the effect of the size and shape of the La2NiO4 nanostructures on their magnetic and photoelectrochemical properties. We satisfactorily refined the powder X-ray diffraction data in the tetragonal space group, I4/mmm. Magnetic susceptibility measurements were performed on all samples within the range of 5–300 K. The Curie–Weiss law determines the magnetic susceptibility of bulk La2NiO4, and a negative value for the Weiss temperature indicates antiferromagnetic exchange. The field-dependent magnetization curves of bulk La2NiO4 suggest a canted antiferromagnetic behaviour. The Mott–Schottky plot demonstrates that La2NiO4 is a p-type semiconducting material with holes as the primary charge carriers. Chronoamperometric measurements for these nanomaterials demonstrate excellent photostability of photocurrent. [ABSTRACT FROM AUTHOR]

Magnetic studies of loess–paleosol sequences have shown that the magnetic properties of loess and its parent material are sensitive to weathering degree. However, the relationship between magnetic properties and weathering processes in red soils of southern China remains unclear due to the diversity of parent rocks and the influence of climate. This study focused on red soils developed on weakly magnetic sandstone, in tropical and subtropical regions of Yunnan, China. The principal element content, magnetic susceptibility, temperature-dependent susceptibility curve (χ–T curve, where χ represents the magnetic susceptibility at the corresponding temperature during the heating and cooling process of the sample, and T represents the temperature during the heating and cooling process.), hysteresis loop and Isothermal Remanent Magnetization (IRM) of the samples were determined, the weathering characteristics and magnetic properties of profile samples were analyzed, and their relationship was examined, as well as the impact of climate change on fine-grained ferrimagnetic minerals and magnetic properties. The results revealed that red soils developed on weakly magnetic sandstone exhibited significant correlations between three magnetic indices, low-frequency magnetic susceptibility (χlf), frequency-dependent susceptibility (χfd), (χpost-pre + χd)/χpara, and the silica-sesquioxide ratio (SAF), indicating that these indices can be used to assess soil weathering. Additionally, this study proposed a new index based on the 1 < Log10Bh < 1.5 mT component obtained from decomposition of the IRM curve, which can also be used to assess soil weathering. The enhancement of magnetic properties in red soils along a single profile was found to be related to the increase in the content of fine-grained ferrimagnetic com-ponents controlled by weathering. Comparing the two climatic regions, it was found that in Yunnan, China, as the climate changes from subtropical humid to tropical humid, the weathering of the red soil profiles becomes stronger, and the fine-grained ferrimagnetic components increase, indirectly enhancing the magnetic properties of red soils. [ABSTRACT FROM AUTHOR]

In mineral exploration, the ores with different magnetic susceptibility can be well delineated by physical property inversion of magnetic data. However, further wide applications of the magnetic inversion method have been seriously restricted by the existence of strong remanence and the computation of large-scale datasets. To solve these two problems, this study innovatively presents an efficient magnetic inversion algorithm in the presence of strong remanence. The weighted data misfit term and regularization term were used to establish the objective function. The detailed related formulas were derived and presented. For numerical computation, the Taylor series approximation was introduced in the objective function to linearize the relationship between the transformed magnetic data and magnetic susceptibility. The objective function was converted to a general Tikhonov form by several matrix transformations. To realize computational efficiency, a fast randomized algorithm was utilized to efficiently solve the Tikhonov problem and to efficiently determine the suitable regularization parameter along with the generalized cross-validation (GCV) method. Comparative tests on synthetic example show the effectiveness and efficiency of the proposed algorithm. The proposed efficient algorithm is successfully applied to two sets of real magnetic data, and the inversion results are verified. [ABSTRACT FROM AUTHOR]

Mangshan section is a scarce and valuable high-sedimentation deposit at the southeastern margin of the Chinese Loess Plateau for high-resolution paleoclimate reconstructions. Although the chronology of the deposit above the paleosol layer S2 has been pinned down on the glacial-interglacial timescale, it still needs to be refined at orbital timescale, especially at the boundary from loess layer L2 to paleosol layer S1. In the age model by correlation of loess grain size with the benthic oxygen isotope (δ18O) records, the lack of paleosol and low magnetic susceptibility during the marine isotope stage 5e are substantially different from the observations in other loess-paleosol sequences on the Chinese Loess Plateau. Here, we analyzed the oxygen isotope composition of microcodium from the upper loess layer L2 and paleosol layer S1 of the Mangshan section to reconstruct the oxygen isotopic stratigraphy. Comparing it with the absolute-dating speleothem δ18O record, we suggest corresponding the paleosol layer S1 to the last interglacial, which is consistent with other loess-paleosol sequences on the Chinese Loess Plateau. Our study provides a new method for the loess chronology by tuning the microcodium δ18O record to the absolute-dating speleothem δ18O record. [ABSTRACT FROM AUTHOR]

Materials that combine spin‐crossover (SCO) and liquid crystal (LC) behavior have gained significant attention due to their potential applications in technological devices, attributed to their easy processability. Herein, we report three neutral heteroleptic Fe(II) complexes: [Fe(dpa‐C4)2(NCS)2] (1), [Fe(dpa‐C6)2(NCS)2] (2), and [Fe(dpa‐C16)2(NCS)2] (3) (dpa‐Cn=N‐alkyl‐N‐(pyridin‐2‐yl)pyridin‐2‐amine; n=4, 6 and 16), which exhibit thermal‐induced spin transition behavior. The transition profiles and temperatures are effectively modulated by the length of the alkyl chains. Longer alkyl chains result in gradual and higher T1/2 values, while the shorter chains lead to abrupt SCO with lower T1/2 (i. e. T1/2=259 K (3) >237 K (2) >211 K (1)). Crystallographic studies reveal the impact of hydrophobic and hydrophilic packing in the crystal lattice, contributing to cooperativity and thereby affecting the SCO behavior. Complex 3 with long alkyl chain substitution, displayed non‐synchronized SCO‐LC behavior due to the thermal motion of the alkyl chains. [ABSTRACT FROM AUTHOR]

AbstractTwo new complexes of copper(II) with bromide ligands and triethylbenzylammonium (TEBA) cations are reported, α-(TEBA)2[Cu2Br6] (1), and (TEBA)2[CuBr4] (2). The syntheses, crystal structures, and magnetic properties are described. 1 crystallizes as bibromide bridged dimers which are linked into square layers via short Br…Br contacts. Variable temperature magnetic susceptibility data indicate ferromagnetic interactions within the dimers (J/kB = 107(4) K) with weak interdimer antiferromagnetic interactions (θ = −3.47(6) K). 2 crystallizes as discrete tetrabromidocuprate anions which are well isolated by the bulk of the TEBA cations. Magnetic susceptibility measurements indicate negligible magnetic interactions in the material. The magnetic properties of the known polymorph (TEBA)2[Cu2Br6] (3) were reexamined in light of the properties of 1 and suggest a significantly stronger interaction within the dimer (J/kB ∼ 110(4) K) than originally proposed. These findings are in agreement considering the nearly identical structures of the Cu2Br62- dimers in 1 and 3. [ABSTRACT FROM AUTHOR]

ABSTRACT Six new complexes of Co(II), Cu(II), and Zn(II) metal were synthesized by microwave‐assisted green method from fluorinated Schiff base ligands. The Schiff base ligands were prepared by the condensation reaction of 4‐(p‐fluorophenyl)‐5‐methyl‐2‐aminothiazole with 4‐methylsalicyldehyde (L1H) and 4‐methoxysalicyldehyde (L2H). FT‐IR, NMR, and HR‐MS spectral data confirm the tridentate nature of ligands in Co(II) and Zn(II) complexes and the bidentate nature in Cu(II) complexes. The elemental analysis and TGA study revealed 1:2 (M:L) stoichiometry in all synthesized metal complexes. Electronic absorption, magnetic susceptibility, and XRD study express the geometry and crystal systems of complexes. The antimicrobial and anticancer analysis of the synthesized ligands and their complexes were achieved. The results indicate that Co(II) and Cu(II) complexes of L2H have greater potency against Gram‐positive bacteria. In contrast, Co(II) and Cu(II) complexes of L1H exhibited greater zone of inhibition against Gram‐negative and fungal strains. Furthermore, among the synthesized ligands and their complexes, the Zn(II) complex of the L2H ligand was found to exhibit potent anticancer activity with IC50 values of 16.18 and 11.10 μM against MDA‐MB‐231 and A549 cell lines compared to other complexes and parent ligands. Molecular docking study against EGFR (PDB: 5XGM) shows strong binding interactions and good binding free energy to support the experimental results. [ABSTRACT FROM AUTHOR]

Aspects of the Quaternary sedimentary geology of South-East Asia have proven problematic in terms of interpretation as to the origins and relationships of the surface sediment layers. The MIS 20 large meteorite impact (c., 788 to 785 ka) occurred within mainland South-East Asia, evident from the well-researched 'Australasian Tektite Strewn Field' which extends over at least one tenth of the surface of the Earth. Key questions include: 1) whether the sedimentary impact signature is preserved in the Quaternary sediment cover of the region and 2) whether stratigraphic indicators and dating methods can discriminate meteorite impact-related associations of sedimentary strata, despite subsequent reworking and diagenesis. The importance of the questions raised relate to the search for the impact site, which has not been located conclusively. Moreover, the sedimentary signatures of meteorite impacts are not well known and the descriptions in this study should aid the recognition of impact signatures elsewhere in the world. An hypothesis was developed: Surface Quaternary sediments across a wide area of mainland South-East Asia represent the effects of a regionally significant meteorite impact. Over one hundred sedimentary sections were logged across five countries in mainland South-East Asia. Methods used, defining the stratigraphy and sedimentology, include computed tomography and X-ray scanning, geochemistry, magnetic susceptibility, and environmental luminescence as well as conventional grain size analyses. Luminescence analyses were applied to samples from key strata to provide age constraints and indications of reworking through dose distributional analysis of quartz fractions. The results of the investigation explain the nature of the stratigraphy and relate it specifically to the meteorite impact. In this manner, the strata and sedimentary signatures of the ejecta from a large cosmic impact are defined across a broad region, rather than being described at singular and isolated sections. The novelty is the spatial scale of the investigation which nevertheless remains detailed. A summary model of impact stratigraphy is presented that applies to the regional ejecta blanket covering at least 300,000 km2. Tektites were co-deposited with the ejecta and not introduced by surface processes reworking the deposits. Similar models may be applicable outside of mainland South-East Asia, wherever other large impacts are suspected to have occurred. [ABSTRACT FROM AUTHOR]

We report a patient who presented clinically with progressive supranuclear palsy (PSP) but was pathologically diagnosed as having primary lateral sclerosis (PLS) with magnetic resonance imaging (MRI) with a quantitative susceptibility mapping (QSM) protocol. A 70‐year‐old man was clinically diagnosed with PSP due to early falls and unresponsiveness to levodopa therapy. Postmortem pathological examination revealed mild loss of Betz cells, gliosis, and transactive response DNA binding protein of 43 kDa (TDP‐43)‐positive inclusions in the motor cortex, leading to the pathological diagnosis of PLS. To explore methods for differentiating PLS from PSP, ante‐mortem QSM images were visually and quantitatively assessed for abnormal increases in magnetic susceptibility in the motor cortex. Prussian blue and Luxol fast blue combined with periodic acid‐Schiff staining were also performed to understand the source of the susceptibility increases. QSM showed clear hyperintense signals in the motor cortex. Magnetic susceptibility in the motor cortex was higher in the PLS patient (Z = 4.7, p < 0.001) compared to normal controls and pathologically diagnosed PSP patients. Pathological examination of the region showed intracortical myelin loss, as well as iron deposition. Underlying pathological processes for the increased magnetic susceptibility include not only iron deposition but also intracortical myelin. Our case suggests that QSM is a potential tool to differentiate PLS from PSP, providing insights for accurate diagnosis and enhancing clinical decision‐making. [ABSTRACT FROM AUTHOR]

The reaction of MnCl2·4H2O with HL ((1-methyl-1H-imidazol-2-yl)methanol) and pdH2 (1, 3 propanediol) in a basic MeCN solution results in the formation of a mixed-valence [Mn20] cationic cluster and two [MnIICl4] counter anions. The metallic skeleton of the cluster describes two geometrically equivalent mixed-valent, linked [MnIII6MnII4] supertetrahedra in which nearest-neighbor metal ions have a different oxidation state. Magnetic susceptibility, magnetization data and heat capacity measurements support evidence of predominant ferromagnetic correlations, leading to a s = 22 spin ground state for the [MnIII6MnII4] supertetrahedra, which are pair-linked by a weak antiferromagnetic coupling. The properties are discussed in the context of the magnetocaloric effect and the potential application of this compound in cryogenic refrigeration. [ABSTRACT FROM AUTHOR]

The occurrences of various illegal activities on beaches require effective geological and environmental investigation methods. Among these methods, the room‐temperature magnetic analysis of soils and sediments represents a nondestructive investigation method for various amounts, types, and grain sizes of magnetic minerals. Here, to verify the usefulness of magnetic analysis in forensic geology research, beach sediment samples from nine sites in the Shimokita Peninsula, Japan, were measured using magnetic analysis to determine the correlations between their concentration‐dependent magnetic parameters and actual regional characteristics. The results revealed that the values of various parameters, namely the low‐field magnetic susceptibility, anhysteretic remanent magnetization, and isothermal remanent magnetization (IRM), were relatively higher at sites near Ti and Fe sedimentary ore deposits. Further, thermomagnetometry results revealed that magnetite was the main magnetic carrier of the sediments. Moreover, pyrrhotite was detected around Ti–Fe mine sites. Furthermore, the results of the investigated parameters reflected the regional characteristics of the amount of magnetic minerals in the beach sediments. Low‐temperature IRM curves and the magnetic grain size parameter also displayed sample‐site‐reflective characteristics. Thus, we believe that magnetic analysis represents an effective method for estimating the provenance of beach sediments in forensic geology research. [ABSTRACT FROM AUTHOR]

The search for spin-reorientation (SR) phase transitions, a spontaneous rotation of ordered magnetic moments, in ferrimagnetic (FiM) materials, which carry a net magnetization, is of fundamental and practical interest for applications in the field of spintronics. In this work, we have investigated Mn self-doped (Er 0.7 Mn 0.3)MnO 3 solid solution with GdFeO 3 -type Pnma perovskite structure by combining specific heat, magnetic susceptibility and neutron powder diffraction measurements. We provide experimental evidence for FiM order below T C = 104 K, and a spontaneous SR transition at T SR = 11 K. A FiM structure appears in all (R 1-x Mn x)MnO 3 compounds with R = Dy–Lu for x ≥ 0.2. But in this structural family, R = Er is the only material with a SR transition. FiM order in (Er 0.7 Mn 0.3)MnO 3 appears with ferromagnetic (FM) ordering of Mn3+ and Mn4+ cations at the B site along the a -direction, which are antiferromagnetically (AFM) coupled with Er3+ and Mn2+ cations at the A site. At T SR , ordered Er3+ change direction from the magnetically harder a -axis to the magnetically easy b -axis and induce a change of the whole FiM structure, including the direction of all Mn spins from the irreducible representation m GM3+ to m GM4+. We calculated the crystal-field (CF) anisotropy for Ho3+ in (Ho 0.8 Mn 0.2)MnO 3 and Er3+ in (Er 0.7 Mn 0.3)MnO 3 , based on the point charge model; the results revealed large magnetic anisotropies. For the FiM structure of (Ho 0.8 Mn 0.2)MnO 3 , the magnetically easy a -axis of Ho3+ keeps the high-temperature magnetic directions along the a -axis and gives rise to a pronounced magnetization reversal effect at low temperature because of a significant rise of Ho3+ ordered moments. On the other hand, for the FiM structure of (Er 0.7 Mn 0.3)MnO 3 , the magnetically easy b -axis of Er3+ gives rise to a SR phase transition at T SR , which does not lead to magnetization reversal even though Er3+ ordered moments rise significantly at low temperatures. [ABSTRACT FROM AUTHOR]

A high‐nuclearity {Ni18} complex (1) with a unique ‘flying saucer’ motif has been prepared from the organic chelate, α‐methyl‐2‐pyridine‐methanol (mpmH), in conjunction with bridging azido (N3−) and peroxido (O22−) ligands. Magnetic susceptibility measurements revealed the presence of both ferro‐ and antiferromagnetic exchange interactions between the metal centres in 1, and the stabilization of spin states with appreciable S values at two different temperature regimes. The end‐on bridging azido and alkoxido groups are in all likelihood the ferromagnetic mediators, while the η3:η3:μ6‐bridging peroxides most likely promote the antiparallel alignment of the metals’ spin vectors, yielding an overall non‐zero spin ground state for the centrosymmetric compound 1. Furthermore, the {Ni18} nanosized cluster behaves as a single‐molecule magnet, exhibiting magnetic hysteresis at low temperatures and two relaxation processes at 15 K and 1.3 K, a very rare phenomenon in polynuclear magnetic 3d‐metal clusters. [ABSTRACT FROM AUTHOR]

The low field magnetic susceptibility (χLF) measured in the 1116‐m‐long Dévaványa core (Pannonian Basin) is a quasi‐continuous record of the Plio–Pleistocene Mid‐European mountain permafrost development. The continuity of fluvial conditions is confirmed by seismic data, and the detrital origin of magnetite is indicated by frequency‐dependent susceptibility measurements, scanning electron microscope, and hysteresis investigations. The χLF record is correlated to the δ18O curve (LR04) supported by palaeomagnetic data. The colour of samples documents precession and obliquity cycles in local facies variations, but the χLF indicates the dominance of 100‐ka eccentricity cycles in the linked mountainous permafrost events. Comparison with orbital solutions revealed that the long‐term development of permafrost occurs as a result of amplitude modulation of the 100‐ka eccentricity cycles. Increases in amplitude of the 100‐ka cycles inhibits permafrost development due to shortened winters. Thus, if extremes are present, the permafrost regions are limited or disappear, but if the 100‐ka eccentricity cycles are attenuated, permanent frost can extend into the temperate zone. This amplitude modulation may also be responsible for the early glaciations during the Pliocene, for the intensification of Northern Hemisphere glaciation, foreshadows cooling in the forthcoming 405‐ka term, and allows the change from 41‐ka cycles to 100‐ka ones in the Mid‐Pleistocene Transition to be explained. The 41‐ka cycles are the result of obliquity‐controlled changes close to the polar cycles, while 100‐ka cycles occur when the amplitude attenuation of the 100‐ka eccentricity cycles enables extended glaciations that suppress the regular 41‐ka cycles. Higher mountains in the catchments enable higher resolution of permafrost records documenting even smaller glaciations. However, the similarities in the overall trends in χLF records of catchment areas with 1500‐m difference in their altitude is a potential counter‐argument when considering the role of tectonic elevations in the expansions of mountainous permafrost. [ABSTRACT FROM AUTHOR]

ABSTRACT Novel imine complexes of ZrO(II), VO(II), and Pd(II) have been synthesized and described using IR, TGA, UV/Vis, and 1HNMR methods, along with powder X‐ray diffraction (XRD), elemental (CHN) analysis, mass spectrometry, molar conductance, and magnetic susceptibility measurements. Conductivity measurements indicate that none of the complexes function as electrolytes. Magnetic susceptibility data confirm the paramagnetism of the VO(II) complex, while ZrO(II) and Pd(II) complexes exhibit diamagnetic properties. Various analyses suggest that divalent cations favor a 1:1 metal‐to‐ligand ratio. Biological studies demonstrated that all complexes possess significant antimicrobial activity against a range of bacterial and fungal strains. We also observed that the antimicrobial potency of the metal complexes follows the order: ZrO(II) > Pd(II) > VO(II) > H2A, with the ZrO(II) complex showing the highest inhibition zone (28 mm) against Gram‐negative bacteria. The antifungal activity against Aspergillus flavus increases in the order VO(II) > ZrO(II) > Pd(II) > H2A. Additionally, the complexes exhibit high cytotoxicity against carcinoma cell lines, including the HepG‐2, when compared with the clinically proven vinblastine. Density functional theory (DFT) calculations were performed to elucidate the equilibrium geometry of the imine ligand and its complexes at the B3LYP level of theory, using the Gaussian 09 program with 6‐311G++(dp) basis set for C, H, O, N, and Cl atoms, and lanl2dz for Pd, V, and Zr atoms. Finally, docking studies revealed potential binding modes at the active sites of bacterial and fungal receptors. [ABSTRACT FROM AUTHOR]

Seafloor massive sulfide (SMS) deposits in different geological settings can have variable magnetic mineralogy, but the mechanism and implications of their spatiotemporal diversity are poorly understood. Based on seabed shallow drilling and surficial sampling of the Yuhuang hydrothermal field, Southwest Indian Ridge, we investigate here whether ubiquitous oxidative weathering affects the magnetic properties of SMS deposits. Microscopic observation and ferrous iron concentrations reveal that seafloor SMS deposits are extensively oxidized; subseafloor SMS deposits are relatively fresh, but oxidation initiates immediately after sample recovery. Negative frequency dependence of magnetic susceptibility likely due to measurement eddy currents is observed for fresh samples but not for oxidized ones, which suggests that oxidative weathering reduces the electromagnetic detectability of SMS deposits in geophysical investigations. Pyrrhotite (and probably other magnetic iron sulfide minerals), magnetite, and hematite are recognized as dominating magnetic (ferromagnetic, sensu lato) minerals in SMS deposits. Electron and quantum diamond microscope observations reveal pyrrhotite mineralization from high‐temperature reducing hydrothermal fluids, while iron‐oxides are mostly oxidation products of primary sulfides. Oxidative weathering modifies paleomagnetic records of SMS deposits. Bulk magnetic parameters vary systematically with enhanced oxidation degree. Temperature‐dependent magnetic measurements are useful tools for distinguishing the oxidation state of SMS deposits. Overall, these findings explain magnetic mineral variability in SMS deposits, linking mineral magnetic properties with seafloor geophysical investigations. Mineral magnetism can also be a redox state proxy for tracing natural and artificial environmental fluctuations in seafloor hydrothermal fields, inspiring novel interdisciplinary research to understand interactions in the dynamic Earth System. Plain Language Summary: Seafloor massive sulfide (SMS) deposits are products of "black smokers" that record information about the evolving Earth System with resource potential. However, our knowledge of the basic magnetic properties of SMS deposits is inadequate to understand their large variability, and therefore, probing the 3‐D structure of SMS deposits with electric and magnetic methods is challenging in seafloor geophysical investigations. In this study, we interpret varying magnetic properties of SMS deposits from the perspective of redox conditions. We find that magnetic minerals in SMS deposits are sensitive to redox state changes, both natural and artificial. Critical magnetic fingerprints of "reduced" and "oxidized" SMS deposits, applicable to seafloor geophysical surveys, are established. These findings contribute to a benchmark for understanding the complex magnetic properties of SMS deposits, which readily bridges microscopic mineral analyses with broad‐scale seafloor geophysical investigations. Mineral magnetism, thus, provides a useful proxy for tracing environmental fluctuations surrounding "black smokers." Key Points: Rapid oxidation occurs after recovering fresh seafloor massive sulfide (SMS) deposits from the subseafloorUnoxidized SMS deposits feature negative frequency‐dependent magnetic susceptibility likely produced by measurement eddy currentsElectron and quantum diamond microscopy reveals that magnetic iron sulfides and iron oxides in hydrothermal products are redox tracers [ABSTRACT FROM AUTHOR]

The paper is devoted to the study of magnetic properties of magnetic colloids placed in porous media. The importance of this study is due to the development of new applications of such media. The paper presents the results of an experimental study of the temperature and frequency dependences of the magnetic susceptibility of magnetic colloids on different bases placed in a porous medium. For this purpose, a kerosene-based magnetic colloid and a water-based magnetic colloid were used. White electrocorundum was used as a porous medium. Magnetic susceptibility was studied by the bridge method in a wide range of frequencies and temperatures. It was found that the frequency and temperature dependences of magnetic susceptibility of bulk and magnetic colloids placed in porous media significantly differ depending on the pore size. The explanation of the obtained results is based on the assumption of the influence of surface forces on the relaxation processes of the magnetic moment of colloidal particles. [ABSTRACT FROM AUTHOR]

Context: In this work, a new polymeric structure was designed consisting of a nanometric sheet of graphene (G) and a polymethylmethacrylate (PMMA) repeat unit, which was designated as PMMA-G. Three degrees of polymerization of PMMA-G were considered: monomer (PMMA-G1), dimer (PMMA-G2), and trimer (PMMA-G3). The effect of incorporating a nanometric sheet of graphene into the molecular structure of PMMA on the modification of some of its main optical, magnetic, and electrical properties was investigated. Currently, the study presented here is of great relevance since various areas of technology require new materials with specific properties for the development of new devices. The results of our study reveal that the dielectric constant of PMMA is reduced when graphene is incorporated. However, a percentage increase of 14.48% in the refractive index of PMMA when graphene is inserted to form the nanocomposite is observed. It is found that the absolute value of molar magnetic susceptibility of PMMA increases considerably when reinforced with graphene. Finally, when reinforcing PMMA with graphene to obtain the PMMA-G nanocomposite, the electrical resistivity increases by almost an order of magnitude. Methods: We used computational tools under Materials Studio (MS) software. We built a PMMA molecule with three degrees of polymerization, graphene sheet, and polymethylmethacrylate-graphene composite (PMMA-G) was built also with three degrees of polymerization using a concentration of 50% graphene over the PMMA polymer. For each structure, we used computational code DMol3 of MS, which is based on the Density Functional Theory, and the geometry optimization process was carried out to obtain the most stable structures. Finally, using the connectivity indices method together with topological properties of the molecular structures, implemented in Synthia computational code of MS software, we calculated the dielectric constant, magnetic susceptibility, refractive index, and electrical resistivity, for pure PMMA and PMMA-G structures for their three degrees of polymerization. The results were analyzed, and the changes in these properties were discussed in terms of the effect of an electric and magnetic field on the molecular structures of PMMA-G with respect to PMMA. [ABSTRACT FROM AUTHOR]

The causes of the formation of bumps on metallographic specimens of sheets and strips subject to inspection are established by analyzing the components of Kovar alloy (trademarked name of Fe29%Ni18%Co precision alloy; named 29NK-VI in Russia) and identifying possible deviations from its manufacturing process, starting from the preparation of the initial melt. It was found out that the formation of bumps is a manifestation of leading diffusion of some alloy components into others, mainly cobalt into nickel. Such a phenomenon may occur in case of significant chemical inhomogeneity of the metallic material caused by the segregation of the components of its initial melt according to their magnetic susceptibility and the refusal to homogenize the resulting ingot. It is argued that bumps on specimens should be considered as a rejection criterion for a material intended for the manufacture of precision parts of vacuum electronic devices, as they are indicative of its unbalanced composition. The residual diffusion phenomena contribute to the change in the phase state of the material, followed by embrittlement, change in precise dimensions, and loss of vacuum in parts of vacuum electronic devices. It is assumed that residual diffusion is one of the causes of the γ→α phase transformation in Kovar at low temperatures. [ABSTRACT FROM AUTHOR]

Over the Nullarbor Plain in South Australia, the Desert Fireball Network detected a fireball on the night of June 1, 2019 (7:30 pm local time), and 6 weeks later recovered a single meteorite (42 g) named Arpu Kuilpu. This meteorite was then distributed to a consortium of collaborating institutions to be measured and analyzed by a number of methodologies including SEM‐EDS, EPMA, ICP‐MS, gamma‐ray spectrometry, ideal gas pycnometry, magnetic susceptibility measurement, μCT, optical microscopy, and accelerator and noble gas mass spectrometry techniques. These analyses revealed that Arpu Kuilpu is an unbrecciated H5 ordinary chondrite, with minimal weathering (W0‐1) and minimal shock (S2). The olivine and pyroxene mineral compositions (in mole%) are Fa: 19.2 ± 0.2 and Fs: 16.8 ± 0.2, further supporting the H5 type and class. The measured oxygen isotopes are also consistent with an H chondrite (δ17O‰ = 2.904 ± 0.177; δ18O‰ = 4.163 ± 0.336; Δ17O‰ = 0.740 ± 0.002). Ideal gas pycnometry measured bulk and grain densities of 3.66 ± 0.02 and 3.77 ± 0.02 g cm−3, respectively, yielding a porosity of 3.0% ± 0.7. The magnetic susceptibility of this meteorite is log χ = 5.16 ± 0.08. The most recent impact‐related heating event experienced by Arpu Kuilpu was measured by 40Ar/39Ar chronology to be 4467 ± 16 Ma, while the cosmic ray exposure age is estimated to be between 6 and 8 Ma. The noble gas isotopes, radionuclides, and fireball observations all indicate that Arpu Kuilpu's meteoroid was quite small (maximum radius of 10 cm, though more likely between 1 and 5 cm). Although this meteorite is a rather ordinary ordinary chondrite, its prior orbit resembled that of a Jupiter Family Comet (JFC) further lending support to the assertion that many cm‐ to m‐sized objects on JFC orbits are asteroidal rather than cometary in origin. [ABSTRACT FROM AUTHOR]

Background and purpose: Susceptibility estimates derived from quantitative susceptibility mapping (QSM) images for the cerebral cortex and major subcortical structures are variably reported in brain magnetic resonance imaging (MRI) studies, as average of all (μall${{{{\mu}}}_{{\mathrm{all}}}}$), absolute (μabs${{{{\mu}}}_{{\mathrm{abs}}}}$), or positive‐ (μp${{{{\mu}}}_{\mathrm{p}}}$) and negative‐only (μn${{{{\mu}}}_{\mathrm{n}}}$) susceptibility values using a region of interest (ROI) approach. This pilot study presents a reliability analysis of currently used ROI‐QSM metrics and an alternative ROI‐based approach to obtain voxel‐weighted ROI‐QSM metrics (μwp${{{{\mu}}}_{{\mathrm{wp}}}}$ and μwn${{{{\mu}}}_{{\mathrm{wn}}}}$). Methods: Ten healthy subjects underwent repeated (test‐retest) 3‐dimensional multi‐echo gradient‐echo (3DMEGE) 3 Tesla MRI measurements. Complex‐valued 3DMEGE images were acquired and reconstructed with slice thicknesses of 1 and 2 mm (3DMEGE1, 3DMEGE2) along with 3DT1‐weighted isometric (voxel 1 mm3) images for independent registration and ROI segmentation. Agreement, consistency, and reproducibility of ROI‐QSM metrics were assessed through Bland‐Altman analysis, intraclass correlation coefficient, and interscan and intersubject coefficient of variation (CoV). Results: All ROI‐QSM metrics exhibited good to excellent consistency and test‐retest agreement with no proportional bias. Interscan CoV was higher for μall${{{{\mu}}}_{{\mathrm{all}}}}$ in comparison to the other metrics where it was below 15%, in both 3DMEGE1 and 3DMEGE2 datasets. Intersubject CoV for μall${{{{\mu}}}_{{\mathrm{all}}}}$ and μabs${{{{\mu}}}_{{\mathrm{abs}}}}$ exceeded 50% in all ROIs. Conclusions: Among the evaluated ROI‐QSM metrics, μall${{{{\mu}}}_{{\mathrm{all}}}}$ and μabs${{{{\mu}}}_{{\mathrm{abs}}}}$ estimates were less reliable, whereas separating positive and negative values (using μp,μn,μwp,μwn${{{{\mu}}}_{\mathrm{p}}},\ {{{{\mu}}}_{\mathrm{n}}},\ {{{{\mu}}}_{{\mathrm{wp}}}},\ {{{{\mu}}}_{{\mathrm{wn}}}}$) improved the reproducibility within, and the comparability between, subjects, even when reducing the slice thickness. These preliminary findings may offer valuable insights toward standardizing ROI‐QSM metrics across different patient cohorts and imaging settings in future clinical MRI studies. [ABSTRACT FROM AUTHOR]

In this work, the magnetic and thermodynamic properties of dilute magnetic semiconductor quantum dots of cylindrical geometry are investigated. The eigenvalue of the quantum system we are considering is obtained by solving the one-electron Schrödinger equation within the framework of the effective mass approach. Then, taking into account the energy spectrum, expressions for thermodynamic quantities and magnetic susceptibility are obtained. The behavior of these expressions depending on temperature is studied using the parameters B , x , R 0 and L 0 . Based on the results obtained, it is established that the average energy, free energy, heat capacity, entropy and magnetic susceptibility at low temperatures depend on the parameter x . Also at low temperatures, when x = 0 , the average energy and free energy exhibit a linear relationship. With increasing temperature, this dependence becomes nonlinear. For x ≠ 0 , the dependence of the average energy and free energy on temperature is a rapidly increasing nonlinear function. In addition, when x ≠ 0 , magnetic susceptibility reaches a maximum at low temperatures. The peak height increases with x and disappears when x = 0 . The peak of magnetic susceptibility decreases as the magnetic field increases when x ≠ 0 and shifts toward higher temperatures. The specific heat forms a Schottky peak at low temperatures and asymptotically approaches C v = 3 k B at high temperatures. [ABSTRACT FROM AUTHOR]

The introduction of the cerium(III) analogue (1‐Ce, Ln = Ce) of (tert‐butoxido)chloridopentakis(tetrahydrofuran)lanthanide(III) tetraphenylborate tetrahydrofuran disolvate, [Ln{OC(CH3)3}Cl(C4H8O)5][B(C6H5)4]·2C4H8O or [Ln(OtBu)Cl(THF)5](BPh4)·2THF (1‐Ln) has been achieved with a structural comparison between the existing solid‐state structures of other rare earth analogues and the title compound at 100 and 180 K. The cation in 1‐Ce is targeted as the cerium(III) ion possesses the criteria to exhibit slow magnetic relaxation in axial point‐charge crystal fields, akin to the dysprosium(III) ion in 1‐Dy. AC magnetic susceptibility experiments reveal no such behaviour for 1‐Ce, putting the viability of cerium‐based SMMs into question. [ABSTRACT FROM AUTHOR]

A combination of magnetic polarity and rock magnetic analysis on the well‐documented section of the Um Sohryngkew River (USR) in the south Shillong Plateau, NE India, produced a sharp reversal marking the C29r‐C29n geomagnetic polarity transition at approximately 65.688 Ma. The rock magnetic studies indicate ferrimagnetic dominant mineralogy with abundance of SSD grains, with an anomalous peak in susceptibility coinciding with Ir‐rich limonitic layer. The magnetic reversal occurs precisely 61 m above the Ir‐rich distinct in situ limonitic layer, indicating that the C29r‐C29n geomagnetic reversal post‐dates the widely accepted Ir‐anomaly based K‐Pg boundary by approximately 355 Ka. Furthermore, the rock magnetic studies indicate its frequency dependence coinciding with the Ir‐rich limonitic layer suggesting a possible dust/aerosol source, while akaganéite is reported from the interval approximately 1 m below peak susceptibility, indicating signature of Deccan volcanism. This study infers the completeness of the USR section with a high rate of sedimentation of approximately 17 cm/ka among the marine K‐Pg boundary sections in the world. [ABSTRACT FROM AUTHOR]

Induced polarisation (IP) is a common geophysical method of exploration for disseminated sulphides. However, in areas with deep (>200 m) and conductive (10 Ωm or less) cover, the technique is less successful as it requires a significant transmitter source and large-offset dipoles. An alternative approach is to use natural-variations in Earth's external magnetic field as the polarising source of the signal, known as natural-field IP. This paper presents a study of extracting IP information from electrical dipole observations during a broadband magnetotelluric (MT) program with a 9 km by 9 km grid of 100 sites above the Vulcan IOCG deposit beneath 750 m of cover, ∼40 km north of the Olympic Dam IOCG mine in South Australia. Inter-site transfer functions between 95 sites and five reference sites at the southeast and southwest corners of the grid were computed to determine a phase shift between horizontal electric fields in the bandwidth of 1–100 s period. Phase shifts of up to – 5 degrees were centred on a region of brecciated hematite where drill holes intersected pyrite, and an inferred fault-zone from passive seismics that marks the boundary between upper crust that is resistive (>100 Ω.m) with high magnetic susceptibility to the south of the fault, and a region of conductive crust (<10 Ω.m) which is low magnetic susceptibility. Our study suggests that the natural-field IP method can identify regions of polarizable minerals beneath deep cover where artificial power sources cannot be feasibly deployed. Such surveys are cheaper, safer, and easier to deploy as only receivers are required, and 3D coverage can be obtained as the source-field is of much larger dimension than the survey array. In addition, the natural-field IP signals are observed as part of the MT program so that both electrical resistivity and polarisation parameters can be determined. [ABSTRACT FROM AUTHOR]

This study investigates Co 40 Fe 40 Dy 20 thin films on glass substrates with thicknesses ranging from 10 nm to 50 nm under four conditions: as-deposited, annealed at 100 °C, 200 °C, and 300 °C. X-ray diffraction (XRD) confirms film amorphousness due to limited thermal energy. Maximum low-frequency alternate-current magnetic susceptibility (χ ac) is observed at thicker films and higher annealing temperatures, with films at 300 °C showing the highest value 0.41. Annealing at 200 °C yields exceptional properties high saturation magnetization (M s) 748 emu/cm³ and low coercivity (Hc) 10 Oe, though Ms decreases at 300 °C due to thermal effects. Electrical resistivity and sheet resistance decrease with thickness and annealing, enhancing carrier transport. Transmittance (%) decreases notably with increased thickness, attributed to thickness and interface effects. Variations in surface roughness from annealing affect properties, with smoother surfaces improving carrier conductivity but reducing optical transparency. Overall, Co 40 Fe 40 Dy 20 exhibits excellent soft magnetic properties suitable for various applications. [ABSTRACT FROM AUTHOR]

This study identifies factors influencing spatial and temporal variations in magnetic susceptibility and heavy metal content in soils and airborne particulate matter within the Kyiv megapolis, Ukraine, and highlights how source apportionment differs in the long and short run. Topsoil magnetic susceptibility anomalies of > 70 × 10−8 m3kg−1 are observed around old factories. The tree bark magnetic susceptibility map provides a record of industry general low emissions for the last 2–3 decades. The patterns of both spatial distributions confirm that factory emissions dominate the composition of particulate falling on the ground in urban area, with exclusion of streets with heavy traffic. Enhanced concentrations of Cu, Ni, and Zn have been found in urban soils, showing a positive correlation with magnetic susceptibility. Re-suspended road dust dominates temporal variation of particulate matter magnetic susceptibility collected on air filters. The air at busy streets is cleaner in winter, when the street dust gets immobilized by snow cover or freezing. Industries in Kyiv pose no significant effect on air quality; the concentrations of Cr, Ni, Cu, Zn, Cd, and Pb are at normal urban level with the exception of the near vicinity to factories. Air in streets with heavy traffic is enriched with Fe and Mn. Principal component analysis reveals different pattern of air pollution for the busy streets and yard areas. Yards are less affected by road dust; thus, contribution of industrial emissions can be distinguished. The results provide context for further quantification of any alterations in ecological state of Kyiv megapolis that may have arisen from socio-economic shocks and direct threats connected to the current war. [ABSTRACT FROM AUTHOR]

Currently, brain iron content represents a new neuromarker for understanding the physiopathological mechanisms leading to Parkinson's disease (PD). In vivo quantification of biological iron is possible by reconstructing magnetic susceptibility maps obtained using quantitative susceptibility mapping (QSM). Applying QSM is challenging, as up to now, no standardization of acquisition protocols and phase image processing has emerged from referenced studies. Our objectives were to compare the accuracy and the sensitivity of 10 QSM pipelines built from algorithms from the literature, applied on phantoms data and on brain data. Two phantoms, with known magnetic susceptibility ranges, were created from several solutions of gadolinium chelate. Twenty healthy volunteers from two age groups were included. Phantoms and brain data were acquired at 1.5 and 3 T, respectively. Susceptibility‐weighted images were obtained using a 3D multigradient‐recalled‐echo sequence. For brain data, 3D anatomical T1‐ and T2‐weighted images were also acquired to segment the deep gray nuclei of interest. Concerning in vitro data, the linear dependence of magnetic susceptibility versus gadolinium concentration and deviations from the theoretically expected values were calculated. For brain data, the accuracy and sensitivity of the QSM pipelines were evaluated in comparison with results from the literature and regarding the expected magnetic susceptibility increase with age, respectively. A nonparametric Mann–Whitney U‐test was used to compare the magnetic susceptibility quantification in deep gray nuclei between the two age groups. Our methodology enabled quantifying magnetic susceptibility in human brain and the results were consistent with those from the literature. Statistically significant differences were obtained between the two age groups in all cerebral regions of interest. Our results show the importance of optimizing QSM pipelines according to the application and the targeted magnetic susceptibility range, to achieve accurate quantification. We were able to define the optimal QSM pipeline for future applications on patients with PD. [ABSTRACT FROM AUTHOR]

AbstractThe compounds catena-[diaquadichloridocopper(II)] bis(4-bromo-2-pyridone) (1) and catena-[bis(5-bromo-2-pyridone)dichloridocopper(II)] (2) have been prepared and characterized crystallographically. Both show bichloride bridged chains of Cu(II) ions with coordinated water molecules in the axial sites for 1 and coordinated 5-bromo-2-pyridone molecules in the axial sites for 2. 1 incorporates two 4-bromo-2-pyridone molecules co-crystallized in the lattice. Variable temperature magnetic susceptibility measurements for 1 indicate the presence of weak antiferromagnetic interactions [J/kB = −7.06(5) K] similar to copper(II) chloride dihydrate, but without that compound’s significant inter-chain interactions and Néel transition. [ABSTRACT FROM AUTHOR]

The mountainous region of central Shandong Province in eastern China is renowned for its high frequency of rainstorms, which often result in devastating flood disasters and have profoundly affected the evolution of local ancient civilizations. To identify ancient flood disaster events, recognizing sediment signatures via multiple indices is important. Here, we investigated the 2018 flood deposits in the Danhe River Basin and sampled short core DH2, on which the grain size, total organic matter (TOM) content, carbonate content, magnetic susceptibility (MS) and pollen were measured. The fine grain size of the flood sedimentary layer reveals that the flood energy in the alluvial plain area is usually weak. The pollen species and concentration and the tree pollen content in the flood layer are significantly greater than those in the soil layer, suggesting that the flood sediment mainly originates from the mountainous areas in the upper reaches of the river, which provides more forest vegetation information. The MS of flood deposits is lower than that of the soil layer, which is mainly related to the intensity of pedogenesis. The research results indicate that the flood sediments in the downstream floodplain areas of small watersheds are predominantly composed of fine-grained components, with characteristics of high loss on ignition, low magnetic susceptibility, high pollen abundance and diverse species. These findings establish a multi-index identification system for paleoflood sedimentation, which has important reference significance for the study of paleoflood sedimentology and hydrology. [ABSTRACT FROM AUTHOR]

In this work, we applied Monte Carlo simulations under the Metropolis algorithm to study the magnetic and magneto-caloric properties of the fullerene C 3 6 system formed with mixed spins: 2 and 5/2. We inspected the effects of not only the crystal magnetic field but also the external magnetic field and the coupling interaction between spins. In the first part, we illustrated the ground state phase diagrams in the planes of the external magnetic field, the coupling interaction between spins and the crystal magnetic field. Also, we have established these phase diagrams for null temperature. It is found that not only the total magnetizations predict the blocking temperature value t B = 5. 5 1 1 7 , but also the magnetic susceptibilities confirm this value. The effects of varying temperature values when fixing the other physical parameters have been outlined. In particular, the studied system showed a shifting between the phases the ferromagnetic phase and the paramagnetic one, at very low temperature values. [ABSTRACT FROM AUTHOR]

AbstractFour mixed-ligand oxidovanadium(IV) complexes, [VIVO(L1-4)(phen)], 1-4, incorporating tridentate dibasic ONO donor hydrazone ligands (H2L1-4, general abbreviation H2L) derived from the condensation of 2-picolinyl hydrazide with 2-hydroxy acetophenone and its 5-substituted derivatives as primary ligands and 1,10-phenanthroline (phen) as auxiliary ligand have been synthesized in excellent yields. The complexes were characterized by elemental analyses, magnetic susceptibility measurements, and various spectral (e.g. IR, UV–Vis and EPR) studies. The molecular structure of one of the four complexes has been determined by single-crystal X-ray diffractometry. In 1, the hydrazone ligand is meridionally disposed of, coordinating through one enolic-O, one phenolic-O, and one imine-N. The other basal position is occupied by one pyridine-N of the phen moiety. The axial positions are occupied by one oxido-O atom and the other pyridine-N atom of the phen moiety. The complexes are paramagnetic with one unpaired electron (μeff ≈ 1.73 BM), suggesting no interaction with the neighboring molecules and are EPR active. The complexes display two d-d transitions, one near 725 and the other near 840 nm due to dxy→dxz,dyz and dxy→dx2−y2 transitions, respectively. The other d-d transition associated with dxy→dz2 transition was not observed as it falls in the UV region, which is masked by highly intense intra-ligand transitions. The complexes display one-electron oxidation peaks in the +0.75 to +0.89 V vs. Ag/AgCl region in the CH3CN solution that show a linear relationship with the Hammett parameter (σ) of the substituents in the aryloxy ring. [ABSTRACT FROM AUTHOR]

The Li-ferrite and graphene oxide (GO) nanocomposites, denoted as (Li 0.5-x/2 ZnₓFe 2.5-x/2 O 4 : x = 0.25), were produced through ultrasonication. The wet method generated Li-ferrite, while the Hummers' method synthesized the GO. X-ray diffraction (XRD) was used to validate the development of Li-ferrite and GO in the nanocomposites. The dimensions of the crystal were determined between 41 and 52 nm, and the porosity of the composites increased with the higher quantity of GO. The scanning electron micrographs (SEM) of ferrites illustrated the formation of uniform and well-defined grains with consistent shapes, exhibiting properties well-suited for effective microwave absorption. The electrical resistance of spinel ferrite was measured at approximately 3.34 × 1011 Ω-cm and significantly lowered as the fraction of GO increased at ambient temperature. As per Maxwell Wagner's model, the electrical permittivity exhibited interfacial polarization with distinct real and imaginary components. The AC conductivity exhibited a positive correlation with the GO content due to the conductive properties of GO and the improved charge hopping mechanism. The frequency exponent parameter's value falls from 0.36 to 0.95 b y the Jonscher's Power law. The magnetic susceptibility of all the samples exhibited a progressive decrease as the temperature increased. The choice of using lithium-based ferrite as filler is made to strengthen the ferrite/GO composites and improve their magnetic and electrical properties. This is undertaken to harness these composites for high-frequency applications, such as their use as microwave absorbers in microwave devices. [ABSTRACT FROM AUTHOR]

The imidophosphorane ligand, [NPtBu3]− (tBu=tert‐butyl), enables isolation of a pseudo‐tetrahedral, tetravalent praseodymium complex, [Pr4+(NPtBu3)4] (1‐Pr), which is characterized by a suite of physical characterization methods including single‐crystal X‐ray diffraction, electron paramagnetic resonance, and L3‐edge X‐ray near‐edge spectroscopies. Variable‐temperature direct‐current magnetic susceptibility data, supported by multiconfigurational quantum chemical calculations, demonstrate that the electronic structure diverges from the isoelectronic Ce3+ analogue, driven by increased crystal field. The four‐coordinate environment around Pr4+ in 1‐Pr, which is unparalleled in reported extended solid systems, provides a unique opportunity to study the interplay between crystal field splitting and spin‐orbit coupling in a molecular tetravalent lanthanide within a pseudo‐tetrahedral coordination geometry. [ABSTRACT FROM AUTHOR]

Exploring the different spin states of central metals in the complex to regulate the anti-tumor activity of cancer cells is of great significance in drug design and clinical use. However, it is a challenge to build a strong coupling between spin states and anti-tumor activities in one system. Herein, we present two complexes {FeII2L2[PdII(CN)4]2}·2H2O (L = Bztpen (1), Bztppn (2); Bztpen = N-benzyl-N,N′,N′-tris(2-pyridylmethyl)ethylenediamine, Bztppn = N-benzyl-N,N′,N′-tris(2-pyridylmethyl)propylenediamine) showing different cytotoxic activities actuated by fine-tuning the structure with different spin states of Fe(II). Magnetic susceptibility measurements and X-ray diffraction revealed that the Fe(II) ion in complexes 1 and 2 remains in the LS and HS state, respectively, at room temperature. Cytotoxicity tests indicate that complex 1 is more biologically effective than complex 2. In complex 2, however, the high-spin Fe(II) played a key role in regulating its in vitro antitumor effects and seems to be associated with ROS-mediated apoptosis. These findings offer a new avenue for developing anti-cancer drugs by designing complexes with different spin states. [ABSTRACT FROM AUTHOR]

Ilmenite-type vanadium oxides exhibit a distinctive cation-dimerization behavior. Here, we report a novel ilmenite-type compound, ZnVO3. Polycrystalline ZnVO3 samples are synthesized under conditions of 10 GPa and 1573 K. The obtained sample crystallizes in the triclinic P1¯ space group. Both V–V and Zn–Zn dimers (dimer-like displacement) are present in the structure, arranged in a ladder-like pattern on each honeycomb lattice. Notably, the V–V dimer persists up to 625 K, surpassing the stability of the V–V dimer state in other ilmenite-type vanadium oxides. Magnetic susceptibility measurements corroborate the formation of direct V–V bond in the dimer. The off-centered position of the Zn2+ ion at the octahedral site, driven by Zn–O covalency and its sp3 nature, promotes the Zn–Zn dimer-like displacement. Cooperative distortions between honeycomb layers further reinforce the V–V dimers. This finding offers insights into controlling cation-dimer strength in crystalline compounds via crystal structure distortions. [ABSTRACT FROM AUTHOR]

The combined use of 2-(2-pyridyl)-1,3-propane-diol (pypdH2) and 2-hydroxymethyl-2-(2-pyridyl)-1,3-propane-diol (pyptH3) in Cu2+/4f chemistry has afforded a new family of isostructural [Cu6M4(pypt)4(pypdH)4(NO3)8] [M = Gd (1), Tb (2), Dy (3), and Y (4)] complexes. These compounds are based on an unprecedented three-layered symmetric [Cu6M4(μ-OR)16]8+ structural core, formed from the connection of the metal ions by bridging alkoxide arms of the organic ligands. Direct current magnetic susceptibility studies for complexes 1–3 revealed the presence of dominant ferromagnetic exchange interactions, suggesting the existence of large spin ground state values. Alternating current magnetic studies indicate the presence of slow-magnetic relaxation in 1–3. [ABSTRACT FROM AUTHOR]

We prepared an organically templated magnet, (enH2)0.5VPO4OH (enH2 = diprotonated ethylenediamine), hydrothermally and characterized its crystal structure by powder X-ray diffraction and Fourier-transform infrared spectroscopy, and its physical properties by magnetization, specific heat and nuclear magnetic resonance measurements and density functional theory calculations. (enH2)0.5VPO4OH consists of uniform chains of V3+ (d2, S = 1) ions and exhibits Haldane magnetism with spin gap Δ = 59.3 K from the magnetic susceptibility χ(T) at μ0H = 0.1 T, which is reduced to 48.4 K at μ0H = 9 T according to the 31P shift. The NMR data evidence the formation of a spin-glass state of unpaired S = 1/2 spins at TS–G ≈ 3 K and indicate that the Haldane S = 1 spin chain segments are much longer in the organically templated magnet (enH2)0.5VPO4OH than in the ammonium counterpart NH4VPO4OH. The single-ion anisotropy D and the interchain exchange J′ in (enH2)0.5VPO4OH and NH4VPO4OH were estimated in density functional calculations to find them very weak compared to the intrachain exchange J. [ABSTRACT FROM AUTHOR]

Two new lanthanide (Ln)-radical one-dimensional (1D) chains {[Ln(hfac)3(Nit-Ph-3,5-bIm)(H2O)]·C4H10O}n (LnIII = Tb 1 and Dy 2) and two two-dimensional (2D) networks [Ln(hfac)3(Nit-Ph-3,5-bIm)]n (LnIII = Pr 3 and Nd 4) were obtained using the multicoordinating nitronyl nitroxide radical ligand Nit-Ph-3,5-bIm (Nit-Ph-3,5-bIm = 2-[3,5-bis(1-imidazole)-phenyl]-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide; hfac = hexafluoroacetylacetonate). For compounds 1 and 2, each Nit-Ph-3,5-bIm radical links two Ln(hfac)3 units via its two imidazolyl-N atoms, thus forming a 1D chain structure. A coordinated water molecule behaving as a hydrogen donor joins one of the uncoordinated NO groups of the Nit-Ph-3,5-bIm radical to generate a 2D layer structure. For compounds 3 and 4, the Nit-Ph-3,5-bIm radical ligand is coordinated to three Ln ions via its one NO group and two imidazolyl-N atoms, generating a unique 2D network. Magnetic studies reveal ferromagnetic coupling between the Ln(III) ion and the NO group mediated by hydrogen bonding in compounds 1 and 2. Furthermore, ac magnetic susceptibilities of compound 2 indicate the slow relaxation of magnetization. [ABSTRACT FROM AUTHOR]

Regulation of the complex structure is greatly significant for the preparation of single-molecule magnets (SMMs). In this work, a multidentate ligand of N,N′-bis(3-carboxy-4-hydroxyphenyl)-1,4,5,8-naphthalenetetradicarboximide (H4NDISA) has been synthesized and reacted with dysprosium(III) salt. By controlling the ratio of metal ions to the ligand and reaction temperature, three new dysprosium(III) complexes are obtained, namely, [Dy2(H2NDISA)3(DMF)3(H2O)10]·1.4DMF·2.6H2O (1), {[Dy(H2NDISA)1.5(DMF)(H2O)4]·3DMF·4H2O}n (2), and {[Dy(HNDISA)(H2O)2]·4H2O}n (3). Their structures are determined by single crystal X-ray diffraction. Crystallographic data demonstrate that complex 1 is a dinuclear dysprosium(III) complex linked by the bidentate ligand of H4NDISA. The intramolecular Dy(III)⋯Dy(III) distance is 23.0861(7) Å. In complex 2, the carboxyl group in one of the ligands adopts a μ-η2:η1 bridging mode to connect two Dy(III) ions, resulting in a Dy(III)⋯Dy(III) distance of 5.2611(5) Å. The other ligand adopts a tetradentate coordination mode to bridge two Dy(III) ions, forming an infinite one-dimensional chain structure along the c axis. Complex 3 displays a two-dimensional network structure. One carboxyl group in the ligand adopts a μ-η1:η1 bridging mode growing along the c axis. Another carboxyl group in the ligand adopts a μ-η2:η1 bridging mode. The shortest distance of Dy(III)⋯Dy(III) is 4.6138(5) Å. DC and alternating current (AC) magnetic susceptibilities of complexes 1–3 were measured. AC magnetic susceptibility measurements show that complexes 1–3 exhibit frequency-dependent ac susceptibilities. [ABSTRACT FROM AUTHOR]

The basin environment is a widely studied subject in both geology and geophysics for its economic significance in energy and mineral explorations. However, the estimation of the basement depth is often a challenging task given the complexity of the basement relief and lateral physical property change. Previous works simplify the problem by only inverting for the depth to the basement, and more recent studies have suggested the need to incorporate the variation of physical properties to improve basement structure imaging. In this study, we develop an inversion method with the associated workflow to simultaneously recover both the depth to a magnetic basement and a laterally varying magnetic susceptibility in the basement rock. To achieve this, we employ a set of constraints on the inverse problem. Particularly, both the recovered susceptibility and basement depth models are bounded below a possible maximum value, and the depth model is guided by a few depth points obtained from the resistivity models that are obtained from the one‐dimensional blocky inversions of magnetotelluric (MT) data. In addition, we apply the fuzzy C‐means (FCM) clustering to the susceptibility model during the inversion and use the inverted cluster centers to differentiate for different geological units in the basement. To show the effectiveness of our work, we compare the existing approaches and our method using two test inversions on one synthetic model resembling the basin–basement environment before demonstrating our method on a field data example with magnetic data collected by the U.S. Geological Survey (USGS) over the Illinois Basin. Our results show improved recovery in both basement relief and susceptibility in the basement rock, and inversion with field data is able to identify three different susceptibility zones in basement rock below the Illinois Basin. [ABSTRACT FROM AUTHOR]

Background: "Stroke" is a generic term meaning sudden onset of a neurologic event and is also called cerebrovascular accident or "brain attack". It is one of the leading causes of death globally and is a significant cause of longterm disability. Magnetic resonance imaging (MRI) provides critical informationin acute stroke that can be used to confirm the diagnosis and direct both acute therapeutic interventions and long-term treatment decisions. MRI can identify regions of hemorrhage, active ischemia, and vessel occlusion. This has made SWI a powerful technique in the evaluation ofstroke patients. Materials and Methods: This is a Cross-sectional study was done in the Radiology Department, Subbaiah Institute of Medical Sciences over the period of 1 year. All clinically suspected patients with a neurological deficit (signs and symptoms like dysphasia/aphasia, hemiparalysis/hemiparesis, ataxia, convulsions) were referred by a neurologist, physicians for MRI brain in medical college and general hospital. Results: In this study, out of the 125patients, 115 patients (92%) had infarcts in the arterialterritory, and 10 patients (8%) had venous infarcts. Hemorrhage was detected in 42 patients (33.6%), of which 33 cases were arterialinfarcts and 9 were venous infarcts. Hemorrhage was seen in 27(35%) out of 77 male patients and 15 (31.2%) out of 48female patients. Hypointense blooming was not seen in 83 patients(66.4%) in this study. Occlusion in TOF-MRA was seen in 25(21.7%) patients out of 115 patients. Susceptibility vessel sign is seen in 20 patients out of 25 patients showing occlusion in TOF-MRA. Loss of flow void on T2 indicating thrombus in the vessel was seen in 5 patients. Conclusion Susceptibility weighted imaging is superior than conventional MR imaging in the detection of haemorrhagic transformation of infarct. SWI can also detect the thromboemboli in the vessels by susceptibility vessel sign. SWI indicates the need for doing perfusion MRI to detect penumbra in cases of DWI-SWI mismatch . [ABSTRACT FROM AUTHOR]