Iron-rich Areas Research Articles

Applying Multimodal Mass Spectrometry to Image Tumors Undergoing Ferroptosis Following In Vivo Treatment with a Ferroptosis Inducer.

Epithelial ovarian cancer (EOC) is the most common form of ovarian cancer. The poor prognosis generally associated with this disease has led to the search for improved therapies such as ferroptosis-inducing agents. Ferroptosis is a form of regulated cell death that is dependent on iron and is characterized by lipid peroxidation. Precise mapping of lipids and iron within tumors exposed to ferroptosis-inducing agents may provide insight into processes of ferroptosis in vivo and ultimately assist in the optimal deployment of ferroptosis inducers in cancer therapy. In this work, we present a method for combining matrix-assisted laser desorption/ionization (MALDI) mass spectrometry imaging (MSI) with secondary ion mass spectrometry (SIMS) to analyze changes in spatial lipidomics and metal composition, respectively, in ovarian tumors following exposure to a ferroptosis inducer. Tumors were obtained by injecting human ovarian cancer tumor-initiating cells into mice, followed by treatment with the ferroptosis inducer erastin. SIMS imaging detected iron accumulation in the tumor tissue, and sequential MALDI-MS imaging of the same tissue section displayed two chemically distinct regions of lipids. One region was associated with the iron-rich area detected with SIMS, and the other region encompassed the remainder of the tissue section. Bulk lipidomics confirmed the lipid assignments putatively assigned from the MALDI-MS data. Overall, we demonstrate the ability of multimodal MSI to identify the spatial locations of iron and lipids in the same tissue section and associate these regions with clinical pathology.

Near-infrared normal spectral emissivity of molten Fe-Ni alloys by electromagnetic heating

The spectral emissivity of molten Fe-Ni alloys is especially critical to analysis the performance and quality of alloy. The near-infrared normal spectral emissivity of molten Fe-Ni alloys was measured at 1000–1600 nm in the temperature range of 1690–1845 K by a self-built measurement apparatus using the electromagnetic heating technology. The measurement apparatus mainly consists of the electromagnetic heating furnace, blackbody, optical fiber spectrometer and colorimetric thermometer. The dependence of near-infrared normal spectral emissivity of Fe-Ni alloys (Ni, Fe10Ni90, Fe30Ni70, Fe50Ni50, Fe70Ni30, Fe90Ni10 and Fe) on wavelength, temperature and composition were systematically investigated. The results show that the emissivity of Fe70Ni30 is higher in the iron-rich area, while the emissivity of Fe30Ni70 is the lowest in the nickel-rich area. Comparison of the measured and simulated results show that the emissivity of molten Fe-Ni alloys is reliable. The emissivity of Fe-Ni alloys provides reliable data for the research of alloys properties.

Automated volumetric determination of high R2 * regions in substantia nigra: A feasibility study of quantifying substantia nigra atrophy in progressive supranuclear palsy.

The establishment of an unbiased protocol for the automated volumetric measurement of iron-rich regions in the substantia nigra (SN) is clinically important for diagnosing neurodegenerative diseases exhibiting midbrain atrophy, such as progressive supranuclear palsy (PSP). This study aimed to automatically quantify the volume and surface properties of the iron-rich 3D regions in the SN using the quantitative MRI-R2 * map. Three hundred and sixty-seven slices of R2 * map and susceptibility-weighted imaging (SWI) at 3-T MRI from healthy control (HC) individuals and Parkinson's disease (PD) patients were used to train customized U-net++ convolutional neural network based on expert-segmented masks. Age- and sex-matched participants were selected from HC, PD, and PSP groups to automate the volumetric determination of iron-rich areas in the SN. Dice similarity coefficient values between expert-segmented and detected masks from the proposed network were for R2 * maps and for SWI. Reductions in iron-rich SN volume from the R2 * map (SWI) were observed in PSP with area under the receiver operating characteristic curve values of 0.96 (0.89) and 0.98 (0.92) compared with HC and PD, respectively. The mean curvature of the PSP showed SN deformation along the side closer to the red nucleus. We demonstrated the automated volumetric measurement of iron-rich regions in the SN using deep learning can quantify the SN atrophy in PSP compared with PD and HC.

Beneficial effect of gelatin on iron gall ink corrosion

Iron gall Inks corrosion causes paper degradation (browning, embrittlement) and treatments were developed to tackle this issue. They often include resizing with gelatin to reinforce the paper and its cellulosic fibers (of diameter approx. 10 µm). This work aimed at measuring the distribution of ink components at the scale of individual paper fibers so as to give a better understanding of the impact of gelatin (re-)sizing on iron gall ink corrosion. For this purpose, scanning transmission X-ray microscopy (STXM) was used at the Canadian light source synchrotron (CLS, Saskatoon). This technique combines nano-scale mapping (resolution of 30 nm) and near edge X-ray absorption fine structure (NEXAFS) analysis. Fe L-edge measurements enabled to map iron distribution and to locate iron(II) and iron(III) rich areas. N K-edge measurement made it possible to map gelatin distribution. C K-edge measurements allowed mapping and discrimination of cellulose, gallic acid, iron gall ink precipitate and gelatin. Three fibers were studied: an inked fiber with no size, a sized fiber that was afterwards inked and an inked fiber sprayed with gelatin. Analysis of gelatin and ink ingredients distribution indicated a lower amount of iron inside the treated cellulosic fiber, which may explain the beneficial effect of gelatin on iron gall ink corrosion.

Regional scale demarcation of alteration zone using ASTER imageries in South Purulia Shear Zone, East India: Implication for mineral exploration in vegetated regions

Regional scale demarcation of alterations is an important preliminary step in mineral exploration. Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) imageries here have been used for alteration mapping and iron-rich (e.g., Gossans) area demarcation in a highly vegetated and relatively unexplored part of Eastern India, namely, South Purulia Shear Zone (SPSZ). The area is surrounded by mineral-rich Singhbhum Shear Zone (SSZ), but the mineral potentiality of SPSZ has not yet been proven. Alteration mineral assemblages are comprise of iron-rich alteration (gossan), clay alteration with varying amounts of iron content, sericitization, ferruginization and chloritization. In this paper, we discuss a few advantages and limitations of commonly used satellite image processing techniques for mineral mapping. We integrate the outputs of band ratio, Principal Component Analysis (PCA), PCA-loading, and thresholding; termed as Directed PCA (DPCA) for delineating mineral potential areas. Our approach mapped the alteration zones with overall 74% accuracy. Our study leads to demarcation of 28% alteration area within a 10 km wide and 60 km long stretch of SPSZ. Two areas, namely, Lawa (23° 1′ 39.31″ N, 86° 4′ 2.55″ E) and Sindurpur (23° 4′ 38.30″ N, 86° 5′ 3.99″ E) were identified as mineral potential zone. Samples from those areas were studied using XRF, microscope and SEM with the conclusive presence of mineralization. Lawa is potential for hydrothermal polymetallic sulfides along with gold mineralization. Sindurpur is potential for secondary iron and manganese mineralization. The study shows that DPCA is a useful tool for ASTER data processing for narrowing target area in preliminary stages of exploration in vegetated zones.

Enhanced identification of trace element fingerprint of prehistoric pigments by PIXE mapping

Abstract The elemental composition of Fe rich rocks used as pigment during prehistoric periods can provide valuable information about the type of material used and their geological origin. However, these materials present several analytical constraints since their patrimonial value involve using non-invasive techniques maintaining a high sensitivity of the detection and the quantification of trace elements. Micro-beam techniques also require to take into account the heterogeneity of these geomaterials from the macroscopic to microscopic scales. Several previous studies have demonstrated that PIXE analysis satisfies these analytical conditions. However, application of micro-PIXE analysis is still complex when thin and discontinuous layer of pigment is deposed on the surface of other materials such as rocks or bones. In such case, PIXE imaging could improve the ability to take into account the high heterogeneity of such archaeological objects. In study, we used PIXE imaging system developed at the NewAGLAE facility in order to visualize distribution of elements associated with iron-rich pigment phase. The results obtained show that PIXE maps can improve the identification of the main trace elements specific to the iron mineral phase. By grouping pixels of iron-rich areas and performing quantitative treatment, it was possible to reveal additional trace elements associated to pigment. This study highlights the contribution of PIXE imaging to the identification of elements associated with mineral phases of interest and to use them as proxies to discriminate different geological materials used in archaeological context.

Kelvin Microprobe Analytics on Iron-Enriched Corroded Magnesium Surface

This work contributes to the better understanding of Kelvin microprobe response to iron re-deposition related surface morphology changes resulting from Mg corrosion caused by iron-rich impurities. Scanning Kelvin probe force microscopy (SKPFM) was performed on polished Mg samples at well-defined surface conditions occurring from corrosive exposure to 0.05 M NaCl electrolyte or dissolved FeCl2. Volta potential difference was measured and mapped across iron-rich areas, unaffected areas of α-Mg, and on FeCl2 exposed areas. Afterward, the obtained potential values were evaluated via the derived mathematical expression, based on model assumptions. Subsequently, they were compared and then correlated to the corrosion process. The article demonstrates what kind of information can be obtained by SKPFM and what conclusion can be drawn toward the detailed explanation of recently reported iron re-deposition mechanism on corroding Mg surface. Finally, suggestions toward the improved application of SKPFM for Mg corros...

Magnetic susceptibility of brain iron is associated with childhood spatial IQ

Iron is an essential micronutrient for healthy brain function and development. Because of the importance of iron in the brain, iron deficiency results in widespread and lasting effects on behavior and cognition. We measured iron in the basal ganglia of young children using a novel MRI method, quantitative susceptibility mapping, and examined the association of brain iron with age and cognitive performance. Participants were a community sample of 39 young children recruited from pediatric primary care who were participating in a 5-year longitudinal study of child brain development and anxiety disorders. The children were ages 7 to 11years old (mean age: 9.5years old) at the time of the quantitative susceptibility mapping scan. The differential abilities scale was administered when the children were 6years old to provide a measure of general intelligence and verbal (receptive and expressive), non-verbal, and spatial performance. Magnetic susceptibility values, which are linearly related to iron concentration in iron-rich areas, were extracted from regions of interest within iron-rich deep gray matter nuclei from the basal ganglia, including the caudate, putamen, substantia nigra, globus pallidus, and thalamus. Controlling for scan age, there was a significant positive association between iron in the basal ganglia and spatial IQ, with this effect being driven by iron in the right caudate We also replicated previous findings of a significant positive association between iron in the bilateral basal ganglia and age. Our finding of a positive association between spatial IQ and mean iron in the basal ganglia, and in the caudate specifically, suggests that iron content in specific regions of the iron-rich deep nuclei of the basal ganglia influences spatial intelligence. This provides a potential neurobiological mechanism linking deficits in spatial abilities reported in children who were severely iron deficient as infants to decreased iron within the caudate.

New tissue priors for improved automated classification of subcortical brain structures on MRI

Despite the constant improvement of algorithms for automated brain tissue classification, the accurate delineation of subcortical structures using magnetic resonance images (MRI) data remains challenging. The main difficulties arise from the low gray-white matter contrast of iron rich areas in T1-weighted (T1w) MRI data and from the lack of adequate priors for basal ganglia and thalamus. The most recent attempts to obtain such priors were based on cohorts with limited size that included subjects in a narrow age range, failing to account for age-related gray-white matter contrast changes. Aiming to improve the anatomical plausibility of automated brain tissue classification from T1w data, we have created new tissue probability maps for subcortical gray matter regions. Supported by atlas-derived spatial information, raters manually labeled subcortical structures in a cohort of healthy subjects using magnetization transfer saturation and R2* MRI maps, which feature optimal gray-white matter contrast in these areas. After assessment of inter-rater variability, the new tissue priors were tested on T1w data within the framework of voxel-based morphometry. The automated detection of gray matter in subcortical areas with our new probability maps was more anatomically plausible compared to the one derived with currently available priors. We provide evidence that the improved delineation compensates age-related bias in the segmentation of iron rich subcortical regions. The new tissue priors, allowing robust detection of basal ganglia and thalamus, have the potential to enhance the sensitivity of voxel-based morphometry in both healthy and diseased brains.

Remote sensing techniques using Landsat ETM+ applied to the detection of iron ore deposits in Western Africa

Remote sensing methods enable the rapid and inexpensive mapping of surface geological and mineralogical features. This capability proves highly useful when working on isolated or inaccessible areas. In this study, several enhancements of Landsat Enhanced Thematic Mapper plus (i.e. band ratios, false colour composites and principal component analysis) were used and evaluated to obtain the best possible visualisation of iron deposits hosted in the Devonian sedimentary rocks of northwestern Africa. In particular, two test sites were chosen: southern Algeria (Djebilet area), where the literature mineralogical and geological data on iron mine fields were already available, and the Western Sahara (the southern flank of Tindouf Basin), which was investigated during a field campaign and was where the occurrence of an analogous sedimentary succession led us to hypothesise the possible presence of exploitable iron deposits. This work demonstrates the usefulness of multispectral imagery in the detection of iron-rich areas and establishes a full remote sensing procedure, which can be profitably applied to a wider region of Western Sahara and can provide interesting perspectives on the possibility of detecting new exploitable iron ore deposits in arid environments.

Contribution of Disturbed Iron Metabolism to the Pathogenesis of Parkinson‘s Disease

Extensive research has revealed a complex pathophysiology in Parkinson’s disease, with different factors contributing to the progressive neurodegeneration. Within this complex pathophysiology, a central role of iron and iron-induced oxidative stress has been discussed for many years, as elevated tissue iron levels, especially within the substantia nigra, have been detected by different techniques in a number of postmortem studies. These findings could be verified intra vitam by advancing MRI techniques, and more recently transcranial ultrasound. Different causes, such as disruption of the BBB, local changes in the normal iron-regulatory system, release of iron from intracellular storages or intraneuronal transportation from iron-rich areas, as well as genetic variations leading to changes in brain iron metabolism, are being discussed to be responsible for the increased tissue iron levels. Although it is still not clear whether increased iron levels constitute a primary or secondary phenomenon in the etiology of Parkinson’s disease, its interaction with many pathophysiologcial cascades and contribution to all forms of Parkinson’s disease, idiopathic as well as monogenetic, stresses the importance of further elucidating the mechanism of brain iron homeostasis and its possible alterations to finally develop pharmacological interventions that may disrupt the chain of pathological events leading to neurodegeneration.

Crystal structure and electrical resistivity studies of Gd(Fe 1− x Co x) 2 intermetallics

From X-ray analysis (295 K) it was found that the cubic, MgCu 2 -type, F d 3 m crystal structure appears across the Gd(Fe 1− x Co x ) 2 series. Electrical resistivity measurements for the Gd(Fe 1− x Co x ) 2 intermetallics were performed in a wide temperature region and the parameters characterizing the resistivity dependence on temperature and composition were determined. The differential of the electrical resistivity against temperature was used to estimate Curie temperatures. The Curie temperature versus x, high and moderately increasing in the iron-rich area, rapidly drops in the cobalt-rich region. The obtained results are compared with the data known for the Dy(Fe 1− x Co x ) 2 series. The Curie temperature is related to both the number of 3d electrons and the de Gennes factor.

Olivine as tar removal catalyst for biomass gasifiers: Catalyst characterization

In the present paper olivine is considered as a prospective in-bed tar removal catalyst for fluidized bed biomass gasifiers. The catalytic activity of olivine is investigated via steam reforming reaction of naphthalene as a model biomass tar compound. It is observed that the calcination of olivine improves the performance of the catalyst. Calcination of olivine is done with air at 900 °C for different treatment times. With increasing calcination time, tar conversion increases; more than 80% naphthalene conversion is observed with 10 h of calcination time for olivine, which is found to be an optimum as further increase in time up to 20 h does not improve the naphthalene conversion. The primary focus of this paper is to characterize the olivine catalysts under investigation (specific composition (Mg 1.78, Fe 0.13) SiO 4) with different calcination times. Techniques such as BET-surface area analysis, XPS, Mössbauer spectroscopy, TPR, SEM/EDX analysis are used to understand the basic phenomena of calcination of olivine. Olivine is observed to be non porous. SEM/EDX show iron rich areas at the surface of olivine after calcination. Severe segregation of iron is observed at the surface due to calcination, which is found to be non-uniform. Mössbauer spectroscopy reveals the appearance of iron(III) phase in the olivine after calcination. Besides the catalytic activity towards tar reduction, olivine is also observed to be highly attrition resistant to be used as an in-bed additive for fluid bed and moving bed biomass gasifiers.

Seasonal variations of phosphate availability in the SW Pacific Ocean near New Caledonia

Seasonal availability of phosphate was assessed by the examination of P pools and turnover times of orthophosphate on 6 cruises between October 2001 and August 2002 in the upper water column (0 to 120 m) of the oligotrophic SW Pacific Ocean near New Caledonia (21°30¹S; 167°E). While the soluble reactive phosphate (SRP) concentration was below the analytical chemical detection limit (30 nM) in summer and fall, it reached detectable values in winter and spring. The annual mean depth-integrated (0 to 100 m) SRP pool was 6.8 mmol m-2 (SD = 3.9, n = 6). Particulate phosphate (PP) and soluble non-reactive phosphate (SNP) pools were, respectively, 1.7 (SD = 0.3, n = 6) and 23.0 mmol m-2 (SD = 4.8, n = 6). A strong seasonal variation of turnover times (T) of orthophosphate was observed (0.17 to 19 d) in the upper water column, with shorter values in summer and fall. Indirectly estimated orthophosphate concentration ([PO4]), based on turnover time measurements, ranged from 56 to 118 nM in winter to 0.3 to 0.8 nM in fall. A seasonal P sufficiency in spring and winter T > 100 h; [PO4] > 20 nM) and a strong deficiency in summer (T < 15 h; [PO4] < 2 nM) and the beginning of fall (T < 5 h; [PO4] < 1 nM) occurred. This P deficiency was larger than at the ALOHA station in the North Pacific Ocean. Primary production and phosphate availability followed the same seasonal pattern. In this iron-rich area known to sustain high N2 fixation rates, phosphate may appear as a key factor controlling carbon production.

Mineralogical characterization of arsenic in uranium mine tailings precipitated from iron-rich hydrometallurgical solutions.

Arsenic-rich uranium mine tailings from the Rabbit Lake in-pit tailings management facility (RLITMF) in northern Saskatchewan, Canada, were investigated to determine the mineralogy and long-term stability of secondary arsenic precipitates formed from iron-rich hydrometallurgical solutions. Total arsenic and iron concentrations in six iron-rich samples of the mine tailings ranged from 56 to 6,000 microg/g and from 12 600 to 30 200 microg/g, respectively (Fe/As molar ratios of 5.3-303). On the basis of stability field diagrams generated from pH, Eh, and temperature measurements on tailings samples (mean values of 9.79, +162 mV, and 2.8 degrees C, respectively), it was concluded that arsenic and iron in the tailings were stable as As5+ and Fe3+. Synchrotron-based X-ray absorption spectroscopic studies of tailings samples, fresh mill precipitates, and reference compounds showed that the arsenic in iron-rich areas of the tailings existed as the stable As5+ and was adsorbed to 2-line ferrihydrite through inner-sphere bidentate linkages. Furthermore, under the conditions in the RLITMF, the 2-line ferrihydrite did not undergo any measurable conversion to more crystalline goethite or hematite, even in tailings discharged to the RLITMF 10 yr prior to sampling.

Bond strength of a laser-clad iron-base alloy coating on Al–Si alloy substrate and its fracture behavior

An S250 MK3 type SEM equipped with a tensile stage was used to measure the bond strength of a laser-clad iron-base alloy coating on an Al–Si alloy substrate. Results showed that the bond strength chiefly depended on the substrate temperature and the Al content added into the cladding. At a low temperature range of 200–240°C, an increase of the substrate temperature resulted in a sharp reduction of cracks and thus a significant rise of the bond strength (from 17 to 104 MPa). At a range of 240–325°C, the bond strength was maintained at a higher level (about 90 to 110 MPa). When the substrate temperature was over 325°C, an unexpected reduction of bond strength was obtained because overmelting of the substrate caused a large dilution in the cladding and produced more low strength aluminides where the cracks initiated. Increasing the Al content from 0 to 3 wt.% in the cladding also reduced flaws or cracks in the transitional region and improved the bond strength. Dynamic observation of the fracture process showed that cracks initiated at the edge of the aluminum-rich area, where some low-strength aluminides (such as FeAl 3 and Fe 2Al 5) existed, propagated to the intermediate area and slowed down in the iron-rich area. Fracture morphology analysis showed that the fracture was brittle.

Microstructural characteristics of iron based alloy laser clad on Al–Si alloy

The present study investigates some special microstructural characteristics and the diffusion phenomenon occurring in the laser cladding of an iron based alloy (a less commonly used alloy) on an Al–Si eutectic alloy. Among the three microstructural regions, i.e. the clad region, the transitional region, and the post-molten region, the transitional region is non-uniform in both microstructure and composition, in which the aluminium rich area displays a mixture of invisible and snowflakelike morphologies while the iron rich area has an ultrafine lamellalike structure and the transitional zone between them appears as a network structure. Differential scanning calorimetry and X-ray diffraction analysis carried out in the transitional region revealed that the possible phases existing in the three areas are γ-Fe, NiAl, and Fe2 Al5 in the iron rich area, α-Al and NiAl3 in the aluminium rich area and FeAl3 , Fe2 Al5 , and NiAl3 in the transitional zone, respectively. Furthermore, the solidification process of the pool and the bond mechanism have been discussed in relation to the microstructural characteristics observed in the experiments, the properties of materials and the extent of thermal conduction.

Microstructural study of oxide layers formed on Zircaloy-4 in autoclave and in reactor part 11: Impact of the chemical evolution of intermetallic precipitates on their zirconia environment

A cause and effect relationship is likely established between the microstructural changes in zirconium alloys under irradiation and the acceleration of their oxidation process. In order to check this hypothesis, comparative microstructural analyses by analytical microscopy are carried out on oxide layers formed in autoclave and in reactor. This part of the study deals with the changes in chemical composition of the intermetallic precipitates, induced by irradiation and oxidation, and their impact on the zirconia microstructure. The main results are: (i) irradiation modifies the redistribution conditions of the iron contained in intermetallic precipitates, partly because it induces progressive amorphisation and iron-depletion of these precipitates, and partly because it may accelerate iron diffusion in zirconia, at least in a transient manner (ii) the oxide layer grown in reactor includes iron-rich areas, especially in its median part. A link between this enrichment and the presence of a significant proportion of tetragonal zirconia is established and discussed.

A Study on the Surface Modification of Green Tuff. Glassy Ceramic Surface Layer Formation by Laser Irradiation.

Tuff is a soft natural stone of low strength being composed mainly of alumina, silica and iron oxide. Since it's surface fails to produce any luster by mechanical polishing. The use of tuff had hitherto been limited to warehouse walls, fences, and so on. Laser treatment produced a white ceramic layer over most of the surface. At the same time, iron rich areas, commonly referred to as “MISO”, were turned black, resulting in an external appearance resembling “INADA”granite stone. The ceramic layer thus obtained is comprised of minute glass bubbles that impart luster to the surface. The surface luster was improved as desired by altering the laser treatment conditions. These results suggest that laser treated tuff can be used as a novel architectural material for interior decoration.

Crassula helmsii (T. Kirk) cockayne: Is it an aggressive alien aquatic plant in Britain?

The occurrence of this alien aquatic macrophyte has rapidly increased during the last decade reaching c. 100 sites mainly in England; these range from shallow acidic seasonal pools to small, more alkaline, nutrient-rich lakes. It is frequently dominant and can grow in an emergent form from 0·7m above the water to a submerged form 1·3m in length, to depths of c. 3m. Plant bimass is generally high with little seasonal cessation of growth. The habit is frequently a dense sward growth which smothers out other flora; it is present in c. ten reserves and is causing concern. It is widely available from aquatic suppliers, it has an enormous potential to propagate from small fragments and has a high growth rate. It is associated with soft sediments and possibly iron-rich areas; this is confirmed by growth trials in static water tanks. In flowing water trials, growth was even faster in water velocities up to 0·32 m s −1, indicating its potential—although no river sites in Britain are yet known. Control by physical removal, often recommended, results in numerous propagules and should be combined with a secondary technique. This initial study suggests that this plant will remain a problem and caution is required to prevent its further spread. Studies of techniques for its control are needed.