Magnetic Susceptibility Values Research Articles

The potential of low-destructive characterization of archaeological sites with stony and eroded soils through geostatistics at the Celtic oppidum of Bibracte (France)

Urbanization during Europe's Late Iron Age brought about a rise of enclosed settlements, or ‘oppida’. These centers of human activity left indelible marks on the environment, influencing its geochemistry. The key goal of the research is to identify zones of anthropogenic activities within eroded and stony soils of the Bibracte oppidum’s ‘empty spaces’. We demonstrate an innovative multivariate and geostatistical approach to integrate relevant geochemical and, when available, geophysical records, thereby facilitating a comprehensive understanding of activity areas within oppida in conditions of soil truncation, erosiona and uneven distribution of cores. Our results indicate varied and potentially intensive past human activities in the southern area of La Terrasse, La Chaume, Le Porrey and Le Verger. This is evidenced by elevated values of magnetic susceptibility and chemical elements such as phosphorus and calcium, which reflect here a diverse historical utilization of these spaces. Our robust multivariate statistical analysis effectively deals with the challenges posed by irregular spatial distribution and missing data, enabling the successful correlation of geochemical and geophysical data and providing compelling evidence of spatially differentiated human activities throughout the oppidum. This extends our understanding of Iron Age urbanization and the nuanced utilization of space within these early urban centers.

High Magnetic Property and Toxicity of Particulate Matter Generated during Welding and Cutting Processes.

Magnetic particulate matter (PM) has raised increasing concern due to its abundant presence in ambient air and negative health impact. However, there is still a lack of comprehensive understanding of their emission sources and toxicities. We here report the observation of high magnetic property and toxicity of PM generated during typical welding and cutting processes. Magnetite, formed during high-temperature operation with less oxygen pressure, was revealed to be the major magnetic contributor. The averaged saturation magnetization and magnetic susceptibility values of fine PM (PM2.5) from welding processes are 1.4-4.2 times greater than those of PM emitted from other unintended emission sources, including iron and steel plants and brake wear, while they are 2.0-5.7 times greater for the cutting processes. Furthermore, PM2.5 from welding and cutting processes are nearly 3.5-4.5 times more neurovirulent and 2.1-7.0 times more likely to induce oxidative stress than those from other magnetic sources in the nerve cells lines. Moreover, all of these magnetic PM2.5 exhibit greater negative health effects than typical atmospheric PM2.5 collected in Shanghai urban regions. These new findings suggest that appropriate occupational protection measures should be implemented for the welding and cutting process to reduce adverse health impacts.

A high-resolution record of Mid- to Late-Holocene environmental changes from a land-locked lake in Schirmacher Oasis, East Antarctica

We present a high-resolution record of environmental changes during the Mid-Late Holocene obtained from a lake sediment core covering the past 4.87 cal kyr BP in the Schirmacher Oasis, East Antarctica. The magnetic signal of Lake L6 was found to be primarily controlled by catchment-derived ferrimagnetic minerals. The period between 4.87 and 3.35 cal kyr BP is marked by several episodes of cold and warm conditions. Warm and wet conditions prevailed in the region from 3.35 to 2.43 cal kyr BP. Magnetic susceptibility values remained generally low indicating the pedogenic formation of fine magnetic grains. The high values of the chemical weathering indices reflected the warm and wet conditions conducive to chemical weathering. A transition to cold and dry conditions was observed at around 2.43 cal kyr BP, representing the Neoglacial cooling, with high values of magnetic concentration-dependent parameters. Following the Neoglacial period, a return to warm and wet conditions was observed at 1.63 cal kyr BP, coeval with the Medieval Climate Anomaly. Our record shows a Late-Holocene cooling marked by a sudden increase in magnetic susceptibility values, which could represent the Little Ice Age, followed by a shift to warmer conditions near the core top.

Magnetic susceptibility in the assessment of toxic heavy metal elements in the surface sediments of Inner Ambon Bay, Maluku province, Indonesia

The Inner Ambon Bay (IAB) is an important area for the economic development of the city of Ambon, one of only a few urban areas in eastern Indonesia. This study is intended to monitor the anthropogenic impact on IAB by employing combined rock magnetic and geochemical analyses on 20 samples collected from IAB and the surrounding rivers. Magnetic susceptibility values of samples in the IAB averaged 26.37× 10−8 m3/kg, which is relatively high and comparable to that of contaminated coastal environments. Magnetic susceptibility correlated positively with certain metals such as Cr, Co, Ni, and Mn but negatively with Hg. Geochemical analyses showed that Hg and Ag contents were relatively high but pose only moderate risk to the environment based on the geo-accumulation index. Furthermore, the potential ecological risk index (PERI) showed that there were two points that showed moderate ecological risk. Multivariate statistical analysis (principal component analysis (PCA), Pearson's correlation coefficient (PCC), and hierarchical cluster analysis (HCA)) outlined that the metallic accumulation in the sediments of IAB was related to lithological, geological, and anthropogenic impacts. Therefore, oil spills and household waste are likely major reasons for anthropogenic pollution in the sediments of the IAB.

Magnetic particle detection as a surface soil source pollution in urban areas: Implication from magnetic and geochemical analysis along the major port city in China

The global concern for the level and sources of urban surface soil pollution has been increasing. In this study, we assessed the efficacy of the environmental magnetic method in identifying the sources of urban surface soil pollution in Ningbo, a prominent city in China. To achieve this, magnetic and geochemical measurements were performed on surface soil samples collected from 114 designated sites， supplemented by polarizing microscope observations. The mass-specific magnetic susceptibility values (χlf) exhibited a wide range, spanning from 25.45 to 1903.85 × 10−8m3kg−1, with an average of 295.45 × 10−8m3kg−1. Notably, lower magnetite concentrations were identified in the urban center, contrasting with higher values observed in the peripheral industrial areas. The average concentrations of Cu, Pb, Zn, and Ca were much higher than the background values. Anthropogenic sources such as traffic emissions, construction dust, and industrial processes emerged as the predominant contributors to surface soil pollution in Ningbo. Fuzzy cluster analysis was employed to discern possible relationships between magnetic properties and pollution sources. The results indicated three categories of pollution. Cluster 1 is related to natural (lithogenic and pedogenic) magnetic mineral sources, and the samples contained abundant quartz or feldspar. Notably, these samples are largely unpolluted. Cluster 2 is associated with a combination of natural and anthropogenic sources. Cluster 3 is dominated by spherical magnetic particles formed by high-temperature combustion. In Cluster 3 topsoil samples, ascertained to be contaminated through magnetic analysis, a significant Spearman correlation was observed between magnetic parameters and Cu, Cr, and Fe. In conclusion, magnetic properties provide a swift and effective method for characterizing surface soil pollution in Ningbo, enabling the tracing of sources for trace metals in the surface soil.

Pine needles as bioindicator and biomagnetic indicator of selected metals in the street dust, a case study from southeastern Iran

Among the different approaches currently being used to evaluate the contamination level of street dust, the magnetic susceptibility of dust and urban tree leaves has received little attention. The key objectives of this study were: (i) to investigate the feasibility of using pine needles as a bioindicator and biomagnetic indicator for estimating the concentration of selected metals in street dust, and (ii) to predict the contamination level of street dust by selected metals using magnetic susceptibility. Street dust and pine tree needle samples were taken from 60 locations in three adjacent cities in Kerman province (Kerman, Rafsanjan, and Sirjan), southeastern Iran. The total concentrations of selected metals, including Cu, Zn, Fe, Mn, Ni, and Pb, and the magnetic susceptibility (χlf and χhf) values of both pine tree needles and street dust samples were determined. Among the three cities studied, samples from Kerman showed the highest magnetic susceptibility and metal concentration values. This could be attributed to the larger size and much higher population density of this city, with more industrial activities and urban traffic than the other two cities investigated. The results also showed that the concentrations of metals in pine needles were strongly correlated (p < 0.01) with those in street dust. The magnetic susceptibility of pine needles and the concentrations of Fe, Pb, Zn, Cu, Ni, and Mn in street dust showed a statistically significant correlation (p < 0.01). A strong and statistically significant correlation (p < 0.01) was also found between magnetic susceptibility and the concentration of metals in pine needles. In conclusion, strong relationships between magnetic properties and metal concentrations of pine needles with those of street dust samples seem to make pine needles a good bioindicator and biomagnetic estimator of the contamination level of metals in street dust.

Topsoil's magnetic and electrical properties in a volcanic and tropical region.

Environmental monitoring by measuring topsoil's magnetic and electrical properties is one practical, quick, and low-cost approach. This method has been used worldwide as a proxy for the presence of potentially toxic elements. However, additional research must be conducted on diverse soil types, geology, and climates. We determined the magnetic and electrical properties of urban and agricultural topsoils in a volcanic region and analyzed them as possible proxies of potentially toxic elements for environmental monitoring. To identify topsoil characteristics, we employed the measurements of magnetic susceptibility and hysteresis, electrical conductivity, total dissolved solids, power of hydrogen (pH), particle morphology, and element contents that were statistically analyzed to identify relevant properties. The result was able to differentiate volcanic soils from urban, industrial, and agricultural areas as well. The value of low-frequency magnetic susceptibility (χLF) in soils from urban areas is higher than 866.0±249.9 ×10-8 m3 kg-1, while the value of χLF in agricultural areas is 208.0±67.8 ×10-8 m3 kg-1. This is reinforced by the relationship between low-frequency and frequency-dependent magnetic susceptibility (χLF-χFD%) in samples from urban areas that fall within the same cluster dominated by coarse-grained magnetic minerals originating from anthropogenic processes. In contrast, the agricultural area forms a separate cluster primarily influenced by pedogenic processes from acid igneous rock minerals. Caution is required for interpreting the magnetic signal due to the high contents of lithogenic magnetic particles inherited from the parent materials of Andisols.

First-principles calculations to investigate thermoelectric efficiency of β-In2S3 under pressure for renewable energy sources

The effect of hydrostatic pressure and temperature on thermoelectric properties of Indium sulfide (β-In2S3) in the tetragonal crystal structure is studied using the first principal calculations and the full potential-linearized augmented plane wave (FP-LAPW) method. The Pedrew-Burke-Ernzerhof generalized gradient approximation (PBE-GGA), local density approximation (LDA) and Tran and Blaha modified Becke-Johnson (TB-mBJ) potential are used for calculation of exchange–correlation potentials. Calculated indirect bandgaps are 0.95, 1.17, and 2.19 eV by LDA, PBE-GGA, and TB- mBJ approximations. Obtained bandgap by TB-mBJ approximation is in good agreement with the experimental result. Calculated density of state spectra show the p orbital of S atoms have significant contribution near the Fermi level. The thermoelectric properties of β-In2S3 under pressure like the Seebeck coefficient SC, the electronic thermal conductivity κe, the electrical conductivity σ, the figure of merit ZT, the electronic specific heat CT,μ and Pauli magnetic susceptibility χT,μ are also calculated. As a result, ZTmax of 0.48 (at 500 K) and 0.41 (at 300 K) are obtained for β-In2S3 at zero pressure. The value of SC for p-type carrier was higher than that of n-type one for β-In2S3. By increasing temperature, electronic thermal conductivity increases but there is no change in electrical conductivity and it remains constant at all temperatures. The maximum values of electronic specific heat and Pauli magnetic susceptibility at zero pressure and room temperature are calculated about 17.168 (J/mol K) and 10.3 × 10−9 (m3/mol), respectively. The electronic specific heat increases with increasing temperature. According to the Curie-Weiss law, the Pauli magnetic susceptibility decrease with increasing temperature. Due to the low lattice thermal conductivity, suitable figure of merit ZT and wide band gap of β-In2S3 have possibilities of applications in the thermoelectric renewable energy sources and solar cells devices.

Preliminary Magnetic Mineralogical Studies of Lake Beloe Sediments (Southern Siberia, Russia)

This article overviews the results of a preliminary magnetic and mineralogical study of the bottom sediments of Lake Beloe (Southern Siberia, Russia). The magnetic and mineralogical properties of the sediments were examined. Their variations were correlated with geological factors. A comprehensive magnetic survey was performed: magnetic susceptibility of samples extracted from three sediment cores was measured; normal remanent magnetization in a continuously increasing external magnetic field of up to 1.5 T was calculated; differential thermomagnetic analysis was carried out based on induced magnetization and scanning electron microscopy (SEM) for certain samples. The magnetic component was divided into three subcomponents based on the normal magnetization curves: ferromagnetic, dia-/paramagnetic, and superparamagnetic. The contribution of each subcomponent to the total magnetization was determined. It was found that the magnetic susceptibility values correlate well across all the studied cores, thus making it possible to compare them. Magnetite and pyrite turned out to be the magnetic minerals distributed throughout almost the entire section. In the Day–Dunlop plot, the studied samples are represented by single-domain (SD) and pseudo–single-domain (PSD) grains. The magnetic components vary consistently along the section, suggesting that the depositional environment underwent substantial changes. Particles similar in composition and morphology to cosmogenic and volcanic spherules were discovered using the SEM method. Based on the obtained results, the boundary between the Pleistocene and Holocene deposits was defined.

Identifikasi Pola Redistribusi Tanah Yang Tidak dan Telah Mengalami Longsor Berdasarkan Nilai Suseptibilitas Magnetik di Daerah Batu Busuk Kota Padang

The research has been carried out to identify patterns of soil redistribution based on magnetic susceptibility values in the Batu Busuk area, Lambung Bukit Village, Pauh District, Padang City. The sample was carried out at three locations, namely Location A (experienced landslides), Location B (not experienced landslides), and Location C (not experienced landslides), with a track length of 40 meters for each location, which has 5 points with variations in depth of 10, 20, 30, 40 and 50 cm. The magnetic susceptibility of the sample was measured using a Bartington Magnetic Susceptibility Meter with a low frequency of 0.465 kHz and a high frequency of 47 kHz. The results showed that most of the samples from Location A and Location C had χfd (%) value of less than 4.0%, while for Location B, it was the opposite. The sample Location B has a pattern where the value of χfd increases with increasing χlf value, not so for the samples for Locations A and C. The susceptibility values for the samples for Location B and Location C decrease with increasing sampling depth, while the sample for Location A fluctuates. The pattern of soil redistribution based on the distribution of sample magnetic susceptibility values for Location B and Location C is relatively more even. On the contrary, Location A. Location A and Location C have experienced erosion, where the erosion rate in Location A is higher than in Location C. In contrast, the soil conditions in Location B are relatively stable.

Monitoring the Centennial Variation of Heavy Metals in Lake Sediments and Influencing Factors Using Environmental Magnetism and Machine Learning Methods

The association between the magnetic properties of lake sediments and heavy metal(loid)s (HMs) is well-documented; however, their correlation with the chemical fractions of HMs remains under-investigated. Developing a robust workflow for predicting HMs risk utilizing various machine learning techniques in conjunction with magnetic analysis presents a complex challenge. This study assessed the predictive efficacy of nine machine learning models for determining the chemical fractions of HMs, employing magnetic parameters derived from sediment cores in a large, shallow lake. These models encompassed random forest, support vector machine, relevance vector machine, extreme gradient boosting, principal component regression, multivariate adaptive regression splines, gradient boosting with component-wise linear models, and lasso and elastic-net regularized generalized linear models. The support vector machine model demonstrated superior performance, achieving coefficient of determination values surpassing 0.8 in both training and testing phases. Through interpretable machine learning approaches, key drivers of HMs were identified among magnetic and physicochemical indicators. Magnetic susceptibility values, high coercivity remanent magnetization, ratios of anhysteretic remanent magnetization to magnetic susceptibility, and anhysteretic remanent magnetization to saturation isothermal remanent magnetization within specific ranges exhibited a positive correlation with Cd, Hg, and Sb. This research significantly advances our understanding of HMs risk assessment in lake sediments by leveraging accessible magnetic measurements within an interpretable machine learning framework.

Effects of solvatomorphism, the nature of a chelating ligand synthon and a counterion on the single crystal XRD structure and SMM properties of paramagnetic monocapped cobalt(II) tris-pyrazoloximates.

A series of monocapped cobalt(II) tris-pyrazoloximates was obtained through the template condensation of the corresponding pyrazoloxime, phenylboronic acid and a suitable cobalt(II) halogenide. Comparing 3-acetylpyrazoloxime versus its methine-containing homolog, the former produced cobalt(II) clathrochelates in substantially higher yields due to the electron donating effect of the methyl substituent, increasing the N-donor ability of its oxime group. Their less N-donor analog with the electron acceptor trifluoromethyl group did not form cobalt(II) complexes of this type. In all their solvent-free and solvent-containing crystals, the encapsulated cobalt(II) ion adopted a high-spin state, as gauged by the Co-N bond lengths of 2.112(4)-2.188(9) Å, and was located almost in the center of its CoN6-coordination polyhedron. Their CoN6-polyhedra had an almost ideal trigonal-prismatic (TP) geometry with distortion angles φ below 4°. This TP-like geometry was assisted by hydrogen bonding between their NH groups and the apical counterion. The absence of methyl groups makes them close to an ideal TP. In contrast, stronger N-H⋯Cl hydrogen bonds occurred in the methyl-containing complex, while the Co-N bond lengths stayed the same at 2.144(2) Å on average. In its solvates with benzene, chloroform and acetone, there is a clear tendency for φ to decrease from 2.7(3)° to 0.47(13)°. The comparable effects of the ribbed methyl substituents, the cross-linking counterion and the lattice solvent on their molecular geometry were observed; the larger the distortions from an ideal TP geometry, the stronger the hydrogen bonds to the corresponding apical halogenide anion. The analysis of the experimental AC- and DC-magnetometry data for their fine-crystalline samples suggests that the passing from the derivative of the methyl-substituted synthon to that of its methine-containing homolog caused a substantial decrease in the magnetic susceptibility value χT and an increase in the QTM contribution to the magnetic relaxation. The effect of a cross-linking halogenide counteranion on the Orbach remagnetization barrier is greater than that of the solvatomorphism of their crystals.

CO2-actuated spin transition tuning in an interdigitated Hofmann-type coordination polymer.

The increased anthropogenic emission level of CO2 urges the development of CO2-responsive materials, but is it possible to regulate the inherent electronic properties through weak physisorption of a ubiquitous gas such as CO2? Herein, we intended to answer this imperative question by the first case of CO2-actuated variable spin-state stabilisation in an interdigitated Hofmann-type coordination polymer [FeIIPd(CN)4L2] (1, L = methyl isonicotinate), showing a wide shift in transition temperature (T eq) from 178 K at P CO2 = 0 kPa to 229 K at P CO2 = 100 kPa. Interestingly, the emergence of a stepped behaviour in the heating process below P CO2 = 10 kPa and overlapping magnetic susceptibility values above P CO2 = 10 kPa elucidate the selective LS state stabilisation solely correlated with the extent of CO2 accommodation. Based on the magnetic response and phase transition diagrams obtained under respective P CO2 , a plausible scenario of the spin-state switching can be interpreted as (1ls + ) → (1hs + ) → 1hs at P CO2 ≤ 10 kPa, → 1hs at 100 kPa < P CO2 ≥ 32 kPa and → → 1hs at 100 kPa, where 1 and 1' represent CO2-free and CO2-encapsulated states, respectively. The cooperative CO2 sorption with SCO based on the varied CO2 pressure corroborates a novel case for developing CO2-responsive magnetic materials henceforth.

Exploitation of Magnetic Susceptibility Data for Soil Stability Analysis: A Watershed Study of the Oued Ghiss Dam in the Central Rif, Morocco

The water erosion of soil in northern Morocco raises significant concerns due to its potential impact on the sustainability and productivity of the land. The objective of our study is to evaluate water erosion by utilizing magnetic susceptibility of soil particles in the watershed of the Oued Ghiss Dam. Magnetic susceptibility measurements were taken on 25cm deep profiles collected from six distinct areas, distributed based on pedology, slope, and land use. The results reveal significant variations in susceptibility. Transects 5 and 6 stand out with significantly higher magnetic susceptibility values compared to other transects, indicating relative soil stability under dense forest cover. Transect 2 also exhibits a range of magnetic susceptibility from 21.05 to 51.67 x 10-8 m³/kg, suggesting relative stability despite slight changes in magnetic susceptibility due to vegetation density and morphometric characteristics. Transects 1, 3, and 4 display lower magnetic susceptibility ranges, indicating signs of active erosion in bare soils. Magnetic signatures of soil particles provide crucial insights into soil dynamics in the Central Rif region of Morocco, emphasizing the impact of geodynamic factors and land use on the degree of evolution and degradation.

Pedogenic effect and the impact of erosion factors on topsoil magnetic susceptibility enhancement

The main aims of this study were to i) investigate the impact of erosion factors including land use, slope position, and lithology on magnetic susceptibility (MS) of soil, and ii) detecting the pedogenic effect on MS enhancement using simple methods, including median absolute deviation (MAD), topsoil-subsoil difference methods, MS magnitude and Dearing’s model. Soil cores were sampled along five slope positions in two transects selected in forested and cultivated lands in a watershed located in north of Morocco. The results showed higher values of MS in the upperslopes in forested land due to soil stability, and lower ones in middleslopes and lowerslopes due to soil erosion. However, MS is higher in cultivated land in middleslopes due to soil deposition and it is lower in the upperslopes due to erosion. The results confirmed the pedogenic effect on MS. This is confirmed by i) enhanced Forster factor and low values of magnetic susceptibility background, ii) dominance of ultrafine super-paramagnetic/stable single-domain ferrimagnetic grains in almost all studied soils, and iii) absence of anomaly in MAD data set and pertinence of the results of MAD and topsoil-subsoil difference methods.

Synthesis, Characterization and Breast Anti-cancer Activity of Iron(II), Cobalt(II), Nickel(II) and Copper(II) Complexes with a Hexadentate Schiff Base Ligand Derived from 2,5-Dihydroxy-1,4-benzoquinone with 5-Amino-2-methylphenol

The complexes of Fe(II), Co(II), Ni(II), and Cu(II) Schiff base ligand derived from 2,5-dihydroxy-1,4-benzoquinone and 5-amino-2-methylphenol were synthesized. The ligand was synthesized by the reaction between the mentioned ketone and amine in 1:2 molar ratio, respectively. The four metal complexes were synthesized by refluxing the ligand with the related metal(II) chloride salts. The synthesized compounds were characterized using FTIR spectroscopy, UV-visible, 1H-NMR, conductivity, atomic absorption, magnetic susceptibility, and thermogravimetric analysis. According to the results, the chelation between metals and ligand occurs with the imine groups and the deprotonated hydroxyl groups of 2,5-dihydroxy-1,4-benzoquinone and 5-amino-2-methylphenol in the ligand. The conductivity test of the four complexes shows the non-electrolytic nature of them. The magnetic susceptibility values of Fe(II), Co(II), Ni(II), and Cu(II) complexes are 4.20, 4.11, 2.97, and 2.34 B.M, respectively. The thermogravimetric and atomic absorption analyses suggest the general chemical formula for the complexes is [M2(L)(H2O)6]. In addition, the ligand and one of its metal complexes (Co(II) complex) were examined against breast cancer cells, and they gave the IC50 of 101.24 and 129.2 µg/mL, respectively. This result suggests that Co(II) complex is a better anti-cancer agent in comparison with the ligand.

Development of the MIITRA QSM template: a high‐resolution magnetic susceptibility template of the older adult brain in the MIITRA atlas space

AbstractBackgroundA QSM template of the older‐adult brain is not yet available. This study constructed a high resolution QSM template of the older‐adult brain for the MITRA atlas using data from a large, diverse, community cohort of non‐demented older‐adults.MethodMagnetic susceptibility maps were generated for the 400 older‐adult paricipants used in the construction of MIITRA using the Morphology Enabled Dipole Inversion(MEDI) on the 3D 5‐echo GRE data(0.7×0.7×1.3mm3) and upsampled to 0.7×0.7×0.65mm3 using nonlocal upsampling. The first GRE echo of each participant were N4 bias field corrected, then upsampled to 0.7×0.7×0.65mm3 using non‐local upsampling and converted to synthetic T1w images using mri_synthsr. The original 3D T1w MPRAGE(1×1×1mm3) data were upsampled to 0.5×0.5×0.5mm3. The synthetic T1w images were linearly registered to the upsampled T1w data and the resulting transformations were used to forward‐map magnetic susceptibility values from the native space of each participant to exact physical locations in MIITRA space. A sparse representation based data‐fusion approach was used on the transformed signals to generate the final 0.5×0.5×0.5mm3 resolution template, denoted as MIITRA_QSM(Fig.1). Since no other magnetic susceptibility template of the older‐adult brain is currently available, we compared MIITRA_QSM to a young adult template named MuSus‐100(1×1×1mm3,100 participants,mean age 24 years) in terms of image quality and magnetic susceptibility properties.ResultVisual showed that MIITRA_QSM template includes fine details, has the expected QSM contrast, highest values in subcortical, brainstem, and cerebellar structures known for their high magnetic susceptibility(especially in older adults), lower values in the white compared to gray matter, and higher values in white matter of the frontal lobe compared to parietal and occipital lobes. When compared to MuSus‐100, MIITRA_QSM showed better delineation of cortical structures and higher image sharpness(Fig.2), as well as higher magnetic susceptibility values in most subcortical brain structures(Fig.3A), Cortical structures from the two templates exhibited more similar magnetic susceptibility values(Fig.3B).ConclusionMagnetic susceptibility values in specific subcortical, brainstem and cerebellar structures are higher in the MIITRA_QSM template compared to a young adult template, probably due to increased metal deposition in these structures with aging. The new template is expected to greatly enhance the accuracy of voxel‐wise and atlas‐based QSM studies on older‐adults.

Development of the MIITRA QSM template: a high‐resolution magnetic susceptibility template of the older adult brain in the MIITRA atlas space

AbstractBackgroundA QSM template of the older‐adult brain is not yet available. This study constructed a high resolution QSM template of the older‐adult brain for the MITRA atlas using data from a large, diverse, community cohort of non‐demented older‐adults.MethodMagnetic susceptibility maps were generated for the 400 older‐adult paricipants used in the construction of MIITRA using the Morphology Enabled Dipole Inversion(MEDI) on the 3D 5‐echo GRE data(0.7×0.7×1.3mm3) and upsampled to 0.7×0.7×0.65mm3 using nonlocal upsampling. The first GRE echo of each participant were N4 bias field corrected, then upsampled to 0.7×0.7×0.65mm3 using non‐local upsampling and converted to synthetic T1w images using mri_synthsr. The original 3D T1w MPRAGE(1×1×1mm3) data were upsampled to 0.5×0.5×0.5mm3. The synthetic T1w images were linearly registered to the upsampled T1w data and the resulting transformations were used to forward‐map magnetic susceptibility values from the native space of each participant to exact physical locations in MIITRA space. A sparse representation based data‐fusion approach was used on the transformed signals to generate the final 0.5×0.5×0.5mm3 resolution template, denoted as MIITRA_QSM(Fig.1). Since no other magnetic susceptibility template of the older‐adult brain is currently available, we compared MIITRA_QSM to a young adult template named MuSus‐100(1×1×1mm3,100 participants,mean age 24 years) in terms of image quality and magnetic susceptibility properties.ResultVisual showed that MIITRA_QSM template includes fine details, has the expected QSM contrast, highest values in subcortical, brainstem, and cerebellar structures known for their high magnetic susceptibility(especially in older adults), lower values in the white compared to gray matter, and higher values in white matter of the frontal lobe compared to parietal and occipital lobes. When compared to MuSus‐100, MIITRA_QSM showed better delineation of cortical structures and higher image sharpness(Fig.2), as well as higher magnetic susceptibility values in most subcortical brain structures(Fig.3A), Cortical structures from the two templates exhibited more similar magnetic susceptibility values(Fig.3B).ConclusionMagnetic susceptibility values in specific subcortical, brainstem and cerebellar structures are higher in the MIITRA_QSM template compared to a young adult template, probably due to increased metal deposition in these structures with aging. The new template is expected to greatly enhance the accuracy of voxel‐wise and atlas‐based QSM studies on older‐adults.

The Content of Magnetic Material in Black Sand of Yeh Gangga Beach

Yeh Gangga Beach is one of the black sand beaches in the Tabanan district. The abundant black sand on this beach stretches along the shoreline with varying grain sizes. This black sand characterizes the specific surface composition as iron sand deposits with high magnetic mineral content. The very high need and use of magnetic minerals in various fields prompt a study of the magnetic mineral content in the black sand of Yeh Gangga beach.The magnetic material content was determined by the extraction method which was expressed in terms of mass fraction. The grain size distribution was determined by the sieve method using a sieve shaker consisting of six mesh numbers, namely 30, 100, 170, 200, 270, and 325.The density of magnetic materials was determined by the principle of mass and volume ratio. The magnetic susceptibility was tested by using a Bartington MS2B susceptibility meter. Meanwhile, the characterization of the elements and their oxides used non-magnetic methods, namely the X-Ray Fluorescence test.The research results show that the magnetic material fraction of Yeh Gangga black sand reach 84.84% with 58.39% of the grains having sizes in the range 150r ≥90 μm. The magnetic susceptibility value is 28.26 10-6 m3/kg with an Fe element content of 85.15% w. The hematite (Fe2O3) content reaches 81.69%. This magnetic material has a density of 1914.43 kg/m3.

Magnetic and Geochemical Properties of Zagreb City Area Soils

This study was performed to derive the first insight into the distribution of low-field volume magnetic susceptibility (MS) throughout Zagreb city, based on in situ field measurements. The most interesting locations were selected for soil sampling and their geochemical contents were determined using ICP-OES. A geostatistical approach was applied to the MS and geochemical results. A median of 0.245 × 10−3 SI units was proposed as the average MS value in Zagreb. The mean concentrations of heavy metals in Zagreb’s soils (in µg/g) are Pb (36.82), Zn (87.77), Cu (30.84), Cd (0.66), Cr (29.04), Co (11.89), and Ni (28.40), and these measurements are relatively low in comparison to the Croatian legislation and the European and world average. Boxplot analyses demonstrate that 45% of the studied elements do not feature any anomalies, while most of the remaining elements indicate only one weak anomaly located at the same site as the MS anomalies. Our statistical analysis found significant correlations between MS and the following elements: Cd, Co, Fe, Mn, Na, Pb, Sb, and Zn. In situ MS measurements proved to be an efficient tool for the initial screening of large areas with elevated concentrations of heavy elements, enabling the cheap and fast assessment of the state of the environment.