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The association and underlying mechanisms between iron deposition and white matter hyperintensity (WMH) remain unclear. In this study, quantitative susceptibility mapping (QSM) was used to quantify deep gray matters iron deposition and to explore the association from both global and regional perspectives. A total of 84 patients with hypertension and 26 healthy controls underwent a strategically acquired gradient echo (STAGE) protocol, and the multi‐echo data were used to reconstruct QSM images. The susceptibilities were used to describe iron content. Global region (RI) susceptibilities were measured in regions of interest, and age‐related thresholds were used to determine high‐iron content region (RII) susceptibilities. Compared with healthy controls, hypertension had higher total WMH scores and regional scores (all p = .001) and higher susceptibilities using the RI or RII analysis (all p < .05). In healthy controls, there was no significant association between susceptibilities and WMH scores. In hypertension, the susceptibilities of deep gray matters were positively correlated with WMH scores (RI analysis: right putamen; RII analysis: bilateral caudate nucleus head, putamen, red nucleus, substantia nigra, and dentate nucleus; age and education corrected p < .05). These findings suggest that iron deposition in deep gray matters was positively associated with WMH in hypertension, especially using the RII analysis.

The optical properties of airborne mineral dust depend on its mineralogy, size distribution, and shape, and they might vary between different source regions. To date, large differences in refractive index values found in the literature have not been fully explained. In this paper we present a new dataset of complex refractive indices (m=n−ik) and single-scattering albedos (SSAs) for 19 mineral dust aerosols over the 370–950 nm range in dry conditions. Dust aerosols were generated from natural parent soils from eight source regions (northern Africa, Sahel, Middle East, eastern Asia, North and South America, southern Africa, and Australia). They were selected to represent the global-scale variability of the dust mineralogy. Dust was resuspended into a 4.2 m3 smog chamber where its spectral shortwave scattering (βsca) and absorption (βabs) coefficients, number size distribution, and bulk composition were measured. The complex refractive index was estimated by Mie calculations combining optical and size data, while the spectral SSA was directly retrieved from βsca and βabs measurements. Dust is assumed to be spherical in the whole data treatment, which introduces a potential source of uncertainty. Our results show that the imaginary part of the refractive index (k) and the SSA vary widely from sample to sample, with values for k in the range 0.0011 to 0.0088 at 370 nm, 0.0006 to 0.0048 at 520 nm, and 0.0003 to 0.0021 at 950 nm, as well as values for SSA in the range 0.70 to 0.96 at 370 nm, 0.85 to 0.98 at 520 nm, and 0.95 to 0.99 at 950 nm. In contrast, the real part of the refractive index (n) is mostly source (and wavelength) independent, with an average value between 1.48 and 1.55. The sample-to-sample variability in our dataset of k and SSA is mostly related to differences in the dust iron content. In particular, a wavelength-dependent linear relationship is found between the magnitude of k and SSA and the mass concentrations of both iron oxide and total elemental iron, with iron oxide better correlated than total elemental iron with both k and SSA. The value of k was found to be independent of size. When the iron oxide content exceeds 3 %, the SSA linearly decreases with an increasing fraction of coarse particles at short wavelengths (< 600 nm). Compared to the literature, our values for the real part of the refractive index and SSA are in line with past results, while we found lower values of k compared to most of the literature values currently used in climate models. We recommend that source-dependent values of the SW spectral refractive index and SSA be used in models and remote sensing retrievals instead of generic values. In particular, the close relationships found between k or SSA and the iron content in dust enable the establishment of predictive rules for spectrally resolved SW absorption based on particle composition

Stellar ejecta gradually enrich the gas out of which subsequent stars form, making the least chemically enriched stellar systems direct fossils of structures formed in the early Universe 1 . Although a few hundred stars with metal content below 1,000th of the solar iron content are known in the Galaxy 2 – 4 , none of them inhabit globular clusters, some of the oldest known stellar structures. These show metal content of at least approximately 0.2% of the solar metallicity ( [ Fe / H ] ≳ − 2.7 ) . This metallicity floor appears universal 5 , 6 , and it has been proposed that protogalaxies that merged into the galaxies we observe today were simply not massive enough to form clusters that survived to the present day 7 . Here we report observations of a stellar stream, C-19, whose metallicity is less than 0.05% of the solar metallicity ( [ F e / H ] = − 3.38 ± 0.06 ( s t a t i s t i c a l ) ± 0.20 ( s y s t e m a t i c ) ) . The low metallicity dispersion and the chemical abundances of the C-19 stars show that this stream is the tidal remnant of the most metal-poor globular cluster ever discovered, and is significantly below the purported metallicity floor: clusters with significantly lower metallicities than observed today existed in the past and contributed their stars to the Milky Way halo. Observations of a stellar stream below the metallicity floor for a disrupted globular cluster are described.

Droughts and climate-change-driven warming are leading to more frequent and intense wildfires 1 – 3 , arguably contributing to the severe 2019–2020 Australian wildfires 4 . The environmental and ecological impacts of the fires include loss of habitats and the emission of substantial amounts of atmospheric aerosols 5 – 7 . Aerosol emissions from wildfires can lead to the atmospheric transport of macronutrients and bio-essential trace metals such as nitrogen and iron, respectively 8 – 10 . It has been suggested that the oceanic deposition of wildfire aerosols can relieve nutrient limitations and, consequently, enhance marine productivity 11 , 12 , but direct observations are lacking. Here we use satellite and autonomous biogeochemical Argo float data to evaluate the effect of 2019–2020 Australian wildfire aerosol deposition on phytoplankton productivity. We find anomalously widespread phytoplankton blooms from December 2019 to March 2020 in the Southern Ocean downwind of Australia. Aerosol samples originating from the Australian wildfires contained a high iron content and atmospheric trajectories show that these aerosols were likely to be transported to the bloom regions, suggesting that the blooms resulted from the fertilization of the iron-limited waters of the Southern Ocean. Climate models project more frequent and severe wildfires in many regions 1 – 3 . A greater appreciation of the links between wildfires, pyrogenic aerosols 13 , nutrient cycling and marine photosynthesis could improve our understanding of the contemporary and glacial–interglacial cycling of atmospheric CO 2 and the global climate system. Oceanic deposition of wildfire aerosols can enhance marine productivity, as supported here by satellite and in situ profiling floats data showing that emissions from the 2019–2020 Australian wildfires fuelled phytoplankton blooms in the Southern Ocean.

Iron, a crucial micronutrient, is an integral element of biotic vitality. The scarcity of iron in the soil creates agronomic challenges and has a detrimental impact on crop vigour and chlorophyll formation. Utilizing iron oxide nanoparticles (IONPs) via nanopriming emerges as an innovative method to enhance agricultural efficiency and crop health. The objective of this study was to synthesize biogenic IONPs from Glycyrrhiza glabra ( G. glabra ) plant extract using green chemistry and to evaluate their nanopriming effects on rice seed iron levels and growth. The synthesized IONPs were analyzed using UV–Vis spectroscopy, Fourier-transform infrared spectroscopy (FTIR), Scanning electron microscope (SEM), Transmission electron microscopy (TEM), and Energy-dispersive X-ray (EDX) techniques. The UV–Vis peak at 280 nm revealed the formation of IONPs. SEM and TEM showed that the nanoparticles were spherical and had an average diameter of 23.8 nm. Nanopriming resulted in a substantial enhancement in growth, as seen by a 9.25% and 22.8% increase in shoot lengths for the 50 ppm and 100 ppm treatments, respectively. The yield metrics showed a positive correlation with the concentrations of IONPs. The 1000-grain weight and spike length observed a maximum increase of 193.75% and 97.73%, respectively, at the highest concentration of IONPs. The study indicates that G. glabra synthesized IONPs as a nanopriming agent significantly increased rice seeds' growth and iron content. This suggests that there is a relationship between the dosage of IONPs and their potential for improving agricultural biofortification.

This study is the first report on the biosynthesized iron oxide nanoparticles (IONPs) which mediate in-vitro callus induction and shoot regeneration in economically important recalcitrant chickpea crop ( Cicer arietinum L.). Here, we used leaf extract of Cymbopogon jwarancusa for the synthesis of IONPs in order to achieve a better biocompatibility. The bioactive compounds in C . jwarancusa leaf extract served as both reducing and capping agents in the fabrication process of IONPs. Field emission scanning electron microscopy (FE-SEM) revealed rods like surface morphology of IONPs with an average diameter of 50±0.2 nm. Energy-dispersive X-ray spectroscopy (EDS) depicted formation of pure IONPs with 69.84% Fe and 30.16% O 2 . X-ray diffractometry (XRD) and attenuated total reflectance-fourier transform infrared (ATR-FTIR) validate the crystalline structure, chemical analysis detect the presence of various biomolecular fingerprints in the as synthesized IONPs. UV-visible absorption spectroscopy depicts activity of IONPs under visible light. Thermo-gravimetric analysis (TGA) displayed thermal loss of organic capping around 500°C and confirmed their stabilization. The biosynthesized IONPs revealed promising results in callus induction, shoot regeneration and root induction of chickpea plants. Both chickpea varieties Punjab-Noor 09 and Bittle-98 explants, Embryo axes (EA) and Embryo axes plus adjacent part of cotyledon (EXC) demonstrated dose-dependent response. Among all explants, EXC of Punjab-Noor variety showed the highest callogenesis (96%) and shoot regeneration frequency (88%), while root induction frequency was also increased to 83%. Iron content was quantified in regenerated chickpea varieties through inductively coupled plasma-optical emission spectrometry. The quantity of iron is significantly increased in Punjab-Noor regenerated plants (4.88 mg/g) as compare to control treated plants (2.42 mg/g). We found that IONPs enhance chickpea growth pattern and keep regenerated plantlets infection free by providing an optimum environment for rapid growth and development. Thus, IONPs synthesized through green process can be utilized in tissue culture studies in other important recalcitrant legumes crops.

The Moon is traditionally thought to have coalesced from the debris ejected by a giant impact onto the early Earth. However, such models struggle to explain the similar isotopic compositions of Earth and lunar rocks at the same time as the system’s angular momentum, and the details of potential impact scenarios are hotly debated. Above a high resolution threshold for simulations, we find that giant impacts can immediately place a satellite with similar mass and iron content to the Moon into orbit far outside Earth’s Roche limit. Even satellites that initially pass within the Roche limit can reliably and predictably survive, by being partially stripped and then torqued onto wider, stable orbits. Furthermore, the outer layers of these directly formed satellites are molten over cooler interiors and are composed of around 60% proto-Earth material. This could alleviate the tension between the Moon’s Earth-like isotopic composition and the different signature expected for the impactor. Immediate formation opens up new options for the Moon’s early orbit and evolution, including the possibility of a highly tilted orbit to explain the lunar inclination, and offers a simpler, single-stage scenario for the origin of the Moon.

Iron is essential for normal physiological function, yet dysregulation of iron metabolism is increasingly recognized as a hallmark of cancers such as glioblastoma (GBM). Recent clinical evidence suggests that systemic iron deficiency anemia (IDA) negatively impacts GBM outcomes in a sex-dependent manner, but the mechanisms linking systemic iron availability to tumor iron metabolism remain poorly understood. Here, we interrogate the impact of systemic iron through dietary modulation (control, iron deficiency (ID), and high iron diets), stratified by sex, on tumor iron handling and GBM outcomes utilizing an immune competent (C57BL/6) GBM (GL261) mouse model. Subsequently, we analyzed clinical samples to evaluate translational value. In the preclinical study, we show that iron deficiency decreased survival in males but conferred a slight survival advantage in females, consistent with prior clinical trends. Among circulating iron markers, only ferritin light chain (FTL), but not ferritin heavy chain (FTH) or serum iron, positively correlated with survival in males but not females. In the brain, contralateral iron levels reflected dietary iron status in males but not females, further supporting sex-dependent regulation of local and circulating iron. Notably, tumor iron content remained unchanged in males but was significantly elevated in ID female tumors, complemented by increased transferrin receptor (TfR1) and FTH expression. In clinical GBM samples, we observed non-statistically significant but similar survival trends across varying iron and ferritin levels, suggesting potential translational relevance of our exploratory model. These findings demonstrate that systemic iron availability exerts a sex-specific effect on tumor iron handling, highlighting a critical relationship between systemic and tumor iron regulation in GBM.

Escherichia coli ferric uptake regulator (Fur) binds a [2Fe–2S] cluster, not a mononuclear iron, when the intracellular free iron content is elevated in E. coli cells. Here we report that the C-terminal domain (residues 83–148) of E. coli Fur (Fur-CTD) is sufficient to bind the [2Fe–2S] cluster in response to elevation of the intracellular free iron content in E. coli cells. Deletion of gene fur in E. coli cells increases the intracellular free iron content and promotes the [2Fe–2S] cluster binding in the Fur-CTD in the cells grown in LB medium under aerobic growth conditions. When the Fur-CTD is expressed in wild type E. coli cells grown in M9 medium supplemented with increasing concentrations of iron, the Fur-CTD also progressively binds a [2Fe–2S] cluster with a maximum occupancy of about 36%. Like the E. coli Fur-CTD, the CTD of the Haemophilus influenzae Fur can also bind a [2Fe–2S] cluster in wild type E. coli cells grown in M9 medium supplemented with increasing concentrations of iron, indicating that binding of the [2Fe–2S] cluster in the C-terminal domain is highly conserved among Fur proteins. The results suggest that the Fur-CTD can be used as a physiological probe to assess the intracellular free iron content in bacteria.

This study presents aerosol iron isotopic compositions (δ56Fe) in the western and central equatorial and tropical Pacific Ocean. Aerosols supply iron (Fe), a critical element for marine primary production, to the open ocean. Particulate aerosols, > 1 µm, were sampled during the EUCFe (Equatorial Undercurrent Fe) cruise (RV Kilo Moana, PI: James W. Murray, 2006). One aerosol sample was isotopically lighter than the crust (δ56Fe = −0.16 ± 0.07 ‰, 95 % confidence interval), possibly originating from combustion processes. The nine other aerosol samples were isotopically heavier than the crust, with a rather homogeneous signature of +0.31 ± 0.21 ‰ (2 SD, n= 9). Given (i) this homogeneity compared to the diversity of their modeled geographic origin and (ii) the values of the Fe/Ti ratios used as a lithogenic tracer, we suggest that these heavy δ56Fe signatures reflect isotopic fractionation of crustal aerosols caused by atmospheric processes. Using a fractionation factor of Δsolution-particle= −1.8 ‰, a partial dissolution of ≈ 13 % of the initial aerosol iron content, followed by the removal of this dissolved fraction, would explain the observed slightly heavy Fe isotope signatures. Such fractionation has been observed previously in laboratory experiments but never before in a natural environment. The removal of the dissolved fraction of the aerosols has not been previously documented either. This work illustrates the strong constraints provided by the use of iron isotopes for atmospheric process studies.