Quantitative imaging of iron dysregulation in multiple system atrophy.

Synthesis, characterization and anticancer activity studies of manganese(II) complexes derived from chitosan thiosemicarbazone vanillin Schiff base.

Prediction models of polycyclic aromatic hydrocarbons in urban road dust via magnetic properties, particle size, and urban environmental features.

The new potentially hexadentate chelate N,N'-bis(2-pyridylmethyl)-N,N'-bis(2-hydroxyethyl)-ethylenediamine (bphnH2) has been synthesized. It possesses a mixed diol/diamine/dipyridine nature and has proven the source of two new FeIII/oxo complexes with unprecedented structures. [Fe2O(bphnH)(bphnH2)][Ce(NO3)6] (1) and [Fe4O(bphn)2(NO3)4](NO3)2 (2) contain pentadentate and hexadentate chelates, respectively. A three-pronged approach comprising fits of experimental magnetic susceptibility data, DFT computations and use of a magnetostructural correlation has been applied to analyse the variable-temperature magnetic properties of 2, the reliability of obtained pairwise Jij exchange interactions, the occurrence and avoidance of overparameterization problems, and the quantitative determination of a very weak long-range interaction in a molecule also containing very strong and medium strength interactions.

Stimuli-responsive molecular materials capable of reversibly modulating their electronic states are of considerable interest for molecular electronics, information storage, and quantum technologies. In this context, we report a series of metallosupramolecular iron(II) [2 × 2] grid complexes constructed from bis-hydrazone ligands that incorporate proton-responsive N-H functionalities within the coordination framework. Single-crystal X-ray diffraction reveals well-defined grid architectures in which the ligand design enables precise tuning of the ligand field through reversible protonation-deprotonation processes. This chemical modulation provides an effective pathway for controlling the electronic configuration of the iron centers. The resulting complexes display spin-state switching behavior triggered by thermal, light, and protonation-deprotonation effects. Spin-state modulation is experimentally demonstrated both in the solid state through variable-temperature magnetic susceptibility measurements and in solution using paramagnetic 1H NMR spectroscopy. Diamagnetic Zn(II) analogues are also prepared as reference systems to elucidate the electronic behavior of the iron(II) grids. These results establish a family of metallosupramolecular iron(II) grid architectures exhibiting multistimuli-responsive spin-state switching and highlight how proton-coupled ligand-field modulation within a supramolecular framework can regulate bistable magnetic behavior. This work provides new insight into the design of chemically addressable spin-state switchable supramolecular systems for responsive molecular materials.

We report the synthesis and characterization of a series: UOS, UOSe and β-US2, the first examples of uranium-chalcogen-containing nanomaterials using colloidal synthetic techniques. The challenge to these syntheses is the oxophilicity of uranium, as uranium dioxide is difficult to avoid and the only actinide nanomaterial reported previously. All reagents, the metal, chalcogen source and solvent, were investigated to understand phase formation in solution. We found a post-synthetic modification, commonly known as digestive ripening, that led to size control of the β-US2 nanoparticles. The phases were confirmed using powder x-ray diffraction and Rietveld analysis, as well as microscopy ( transmission electron microscopy), and magnetic susceptibility measurements. The oxychalcogenide nanomaterials are antiferromagnetic, in contrast to previously reported UO2 nanoparticles. As found in bulk β-US2, the nanoparticles are paramagnetic, with a moment consistent with localized f electrons.

A series of six cesium-containing rare-earth selenosilicates, CsLaSiSe4, CsPrSiSe4, CsNdSiSe4, CsSmSiSe4, CsGdSiSe4, and CsTbSiSe4, with the general formula CsRESiSe4 (RE = La, Pr, Nd, Sm, Gd, and Tb), have been successfully synthesized using a flux-assisted boron chalcogen mixture (BCM) method. Single-crystal X-ray diffraction analysis confirms that all compounds crystallize in the noncentrosymmetric orthorhombic space group P212121, adopting a layered structural framework with [RESiSe4]- two-dimensional layers. The magnetic properties of CsPrSiSe4, CsNdSiSe4, CsSmSiSe4, and CsGdSiSe4 were investigated using polycrystalline powder samples. Temperature-dependent magnetic susceptibility measurements exhibit Curie-Weiss behavior across a wide temperature range, indicating predominantly paramagnetic interactions. The effective magnetic moments are determined to be 3.46, 3.61, 1.47, and 7.1 μB per formula unit for CsPrSiSe4, CsNdSiSe4, CsSmSiSe4, and CsGdSiSe4, respectively. Additionally, band gaps estimated from UV-vis spectroscopy are 2.7(1) eV for CsLaSiSe4, 2.5(1) eV for CsPrSiSe4, 2.4(1) eV for CsNdSiSe4, 2.0(1) eV for CsSmSiSe4, and 2.5(1) eV for CsGdSiSe4, confirming the semiconducting nature of these materials. The electronic structures were further investigated using first-principles density functional theory (DFT) calculations to provide deeper insight into their bonding and electronic properties.

Road dust is a major carrier of potentially toxic elements (PTEs) in urban environments. This study characterizes road dust samples collected in the vicinity of public schools (n = 17) to assess their physicochemical properties, mineralogy, chemical composition, magnetic susceptibility, particle morphology, contamination indices, and gastric bioaccessibility of some PTEs (< 250µm fraction). Samples were mainly composed of quartz, with feldspars, Σphyllosilicates, carbonates, and magnetite-maghemite, revealing geogenic and anthropogenic sources, e.g., tire wear, brake abrasion, and resuspended pavement debris. The fraction < 106µm was enriched in PM10, suggesting high potential for inhalation and ingestion. The geoaccumulation index was generally < 1, indicating low contamination, although isolated Zn hotspots reached moderate levels. Pollution Index identified Zn as the main pollutant (max. 11.6), while Pollution Load Index classified the area as slightly polluted. Bioaccessibility tests showed negligible gastric solubility for As and Cr, while Ni, Cu, and Pb exhibited moderate to high bioaccessible fractions, with increased ingestion risk despite moderate total concentrations. SEM-EDS analysis revealed carbonaceous soot, Fe-oxide brake debris, alloy fragments, Ti-rich paint particles, and occasional As-sulfide grains in respirable sizes. Road dust showed moderate contamination but included some hotspots with bioaccessible PTEs fractions relevant to children exposure, highlighting the need for targeted dust-control measures and periodic monitoring. Simultaneously, indoor Rn concentrations in classrooms were high (mean 1540 ± 921Bq/m3), posing a cancer risk by inhalation. The combined assessment of road dust and Rn exposure provided an integrated evaluation of inhalation and ingestion pathways in school environments, underscoring the importance of multi-hazard air-quality monitoring.

The origin of V-V dimerization, a characteristic phenomenon observed in ilmenite-type vanadium oxides, remains unclear. To elucidate this origin, we must first clarify the conditions under which such dimers can form. Here, we investigate the effect of Ti4+ substitution at the V4+ sites in MgVO3, a representative ilmenite-type vanadium oxide. Synchrotron X-ray diffraction measurements revealed that increasing the Ti content lowers the structural phase transition temperature associated with V-V dimerization. Furthermore, magnetic susceptibility measurements indicated that Ti substitution suppresses the formation of V-V bonds, which are disrupted concomitantly with the structural phase transition. MgV0.70Ti0.30O3 adopts a rhombohedral ilmenite-type structure without long-range V-V dimer ordering even at low temperatures. This study provides experimental insights into the stability and collapse of V-V dimers.

Chloroplasts are significant generators of reactive oxygen species and are crucial for plant immunity. However, how these subcellular organelles detect external stimuli and initiate specific immune responses remains largely unknown. Here we identified a plasma membrane (PM)-anchored N-myristoylated protein, TaMP, which detaches from the PM and relocalizes to chloroplasts upon exposure to pathogen-associated molecular patterns. We also uncovered a secreted protease from the rust fungus, Puccinia striiformis f. sp. tritici, that hijacks and promotes TaMP relocalization, increasing wheat susceptibility to rust fungus. In chloroplasts, TaMP interacts with TaClpS1, an adaptor subunit of the Clp protease complex. TaMP-TaClpS1 interaction enhances TaClpS1 binding to TaGluTR, promoting its degradation. Critically, TaGluTR positively regulates wheat stripe rust resistance by increasing accumulation of tetrapyrrole intermediates and enhancing retrograde signalling. However, TaMP attenuates TaGluTR function by promoting its degradation, ultimately impairing wheat resistance to pathogens. Overall, this study reveals a novel and specific susceptibility mechanism in which a rust fungus effector triggers the relocalization of a host protein from the PM to the chloroplasts to suppress organellar immune functions.

Thrombolytic recanalization rates in acute ischemic stroke (AIS) patients remain low. Magnetic resonance susceptibility vessel sign has been correlated with reduced thrombolytic susceptibility. However, the driving mechanisms have not been clarified. High-field magnetic resonance imaging is used to study relaxation rates and compaction of embolus analogs undergoing simulated AIS with varying pressures. Microscopy and perfusion tests are used to study the effect of compaction on clot microstructure and permeability, respectively. Pressure dependent compaction alters clot microstructural characteristics and increases the R2 relaxation rate. Following compaction, the R2 in red blood cell (RBC) rich clots increases up to 224%, corresponding to a twofold increase in RBC volume fraction and polyhedrocyte formation. RBC and fibrin dominant clot permeabilities decrease by 78% and 97%, respectively, when compaction pressure increases 50 mmHg. Compacted red blood cell rich clots are the most likely to present with susceptibility vessel sign and have the lowest permeability. Our results suggest that increased clot constituent density due to compaction can lead to susceptibility vessel sign and elevated thrombolytic resistance by limiting thrombolytic perfusion. This is the first study to evaluate the clinical relevance of clot compaction during AIS using multiple imaging techniques.

To measure magnetic susceptibility (χ) with Quantitative Susceptibility Mapping (QSM) and evaluate its repeatability using four phantom doping materials relevant to QSM applications. A cylindrical phantom was constructed containing vials of agarose gel doped with two paramagnetic materials (ferritin, USPIO) and two diamagnetic materials (CaCl2, CaCO3) at five concentrations each. Single orientation QSM measurements (MEDI+0) were carried out on the phantom at 3 and 7 T. We measured molar susceptibility (χmol) from QSM and evaluated the precision of QSM measurements using the standard deviation of the ROI measurement (SDROI). We evaluated material lifespan by conducting a t-test of χmol at various timepoints. χmol (ppm L mmol-1) were measured as 1.67 ± 0.24 and 0.74 ± 0.09 (USPIO: 3 and 7 T, respectively), 10-2 × (8.13 ± 1.35; 8.13 ± 1.19) (Ferritin: 3; 7 T), 10-4 × (-2.68 ± 0.24; -2.71 ± 0.37) (CaCl2: 3; 7 T), and 10-5 × (-9.52 ± 1.44; -9.53 ± 1.18) (CaCO3: 3; 7 T). We observed no significant changes in molar susceptibility for ferritin and CaCO3 over the measured timeframes (24 and 15 months, respectively). We recommend using ferritin as a paramagnetic dopant. Further research is required to identify a diamagnetic dopant with a lower electrical conductivity and a lower ratio of R2*/B0 to χ.

Magnetic biomonitoring by lichen transplant for the preventive conservation of cultural heritage - a study in the Jerónimos Monastery (Lisbon, Portugal).

The structural, thermal, electrical transport, and magnetic properties of ternary compounds BaT2P2(T=Ru, Pd) are reported together with electronic structure calculations. Our results show that BaRu2P2crystallises in the layered tetragonal ThCr2Si2-type structure (space groupI4/mmm) whereas BaPd2P2adopts the primitive tetragonal CeMg2Si2-type structure (space groupP4/mmm). The combined experimental results and electronic structure calculations suggest metallic and diamagnetic ground states for both materials. Electrical transport measurements further indicate non-Fermi liquid behaviour at low temperatures. Notably, BaRu2P2exhibits an anomalous feature in the magnetic susceptibility atT∼260K, similar to that observed in BaRu2As2. A comparison between the bare density of states obtained from electronic structure calculations and the experimentally estimated values suggests the presence of strong correlation effects in the material. Furthermore, the heat capacity of BaPd2P2, calculated using the full phonon dispersion relation, is in good agreement with the experimental data, particularly at low temperatures, highlighting the significant contribution of optical phonon branches toCpin this temperature range.

Doubly reduced phthalocyanine complexes remain largely unexplored despite their potential relevance for molecular spin-based applications. Herein, we report the synthesis of a series of crystalline complexes, {cryptand(Cs+)}2[M(Pc)4-]2-·xC7H8 (M = VIVO, CuII, and SnII, x = 1.0-1.3), obtained via reduction of the corresponding metal phthalocyanines with cesium anthracenide in toluene. X-ray diffraction, optical spectroscopy, EPR spectroscopy, and magnetic measurements demonstrate ligand-centered two-electron reduction, affording spin-free (Pc)4- ligands while preserving the metal oxidation states. The vanadyl and copper complexes exhibit isolated S = 1/2 spin systems, whereas the tin analogue is diamagnetic. Continuous-wave and pulsed EPR spectroscopy, supported by magnetic susceptibility data, reveal slow magnetic relaxation and quantum coherence in the paramagnetic complexes. In particular, the copper complex shows field-induced slow relaxation with relaxation times up to 0.1 s. Spin coherence was observed in magnetically diluted vanadyl and copper systems, including crystalline dispersions and frozen solutions. The key role of the sample preparation strategy in relaxation behavior was demonstrated. These findings demonstrate that doubly reduced phthalocyanine complexes can serve as robust platforms for molecular S = 1/2 spin qubits. Additionally, the straightforward reductive synthetic approach provides access to phthalocyanine-based systems that are mostly poorly soluble, opening new opportunities for the design of functional molecular materials.

A copper(II)–niacin (nicotinic acid, vitamin B3) complex was synthesized in aqueous medium and investigated using a combination of spectroscopic, thermal, and electrochemical techniques to explore its coordination behavior and physicochemical properties. Elemental analysis supported the proposed formulation [Cu(niacin)2·xH2O]. Fourier transform infrared spectroscopy revealed significant changes in the carboxylate and pyridine vibrational bands, indicating interaction between niacin and the Cu(II) center. UV–visible spectroscopy showed intense ligand-centered transitions in the UV region along with weak d–d transitions characteristic of Cu(II) complexes. Fluorescence measurements demonstrated strong quenching upon coordination, suggesting effective metal–ligand electronic interactions. Thermogravimetric analysis indicated a multistep decomposition pattern leading to CuO as the final residue, confirming moderate thermal stability. Magnetic susceptibility measurements (μ_eff ≈ 2.41 BM) were consistent with a paramagnetic Cu(II) species. Conductivity studies suggested weak electrolyte behavior in aqueous solution, while cyclic voltammetry revealed quasi-reversible Cu(II)/Cu(I) redox activity. These results collectively support the formation of a Cu(II)–niacin coordination system, although the exact coordination geometry remains tentative without crystallographic evidence.

White matter hyperinxtensity (WMH) and normal-appearing white matter (NAWM) are critical markers for tracking disease progression in cerebral small vessel disease (CSVD), indicative of a spectrum of white matter injury. The core pathological alteration underlying such injury is the disruption of myelin integrity and loss of axons. We hypothesized that the myelin content in WMH and NAWM may exert distinct effects on brain networks and cognition in CSVD. A total of 129 diagnosed CSVD patients were retrospectively enrolled. Myelin content was assessed with sub-voxel precision using iterAtive magnetic suscePtibility sources sepARaTion Quantitative Susceptibility Mapping (APART-QSM). Structural network redundancy was derived from diffusion tensor imaging (DTI). WMH and NAWM masks were generated. Associations between WMH/NAWM myelin content, structural network redundancy, and cognitive performance were examined using partial correlation and mediation analyses. Myelin content was significantly higher in NAWM than in WMH. Decreased structural network redundancy was significantly linked to myelin loss in NAWM but not in WMH. Moreover, redundancy indirectly linked NAWM myelin to cognition, whereas no such indirect pathway was observed for WMH myelin. No direct or total effect of myelin content on cognition was observed. These findings highlight the critical role of NAWM-related myelin integrity in preserving cognition through its association with structural network redundancy in CSVD.

We introduce a magnetic extension of the Hückel molecular orbital (HMO) method in which the effect of an external magnetic field is incorporated through the Peierls substitution. In this formulation, the \pi -electron Hamiltonian of a conjugated molecule becomes a complex-weighted hopping operator defined on the hydrogen-depleted molecular graph. Under the standard Hückel assumptions, the corresponding one-electron Hamiltonian matrix is proportional to the Hermitian adjacency matrix of the graph, providing a physical realization of Hermitian adjacency operators within molecular electronic structure theory. The magnetic-HMO framework enables the calculation of global flux-dependent observables such as orbital magnetization and orbital susceptibility from the magnetic adjacency spectrum, while local observables such as bond and ring currents are determined by the corresponding eigenvectors or one-particle density matrix. Applications to polycyclic aromatic hydrocarbons show that the magnetic response of \pi -electron systems is strongly controlled by molecular topology. In particular, linearly fused systems exhibit regular flux-dependent oscillations in the orbital magnetization, whereas nonlinear and extended molecules display more complex spectral rearrangements associated with multiple conjugation

Three new diruthenium(II,II) naphthyridine complexes with β-diketonate ligands, [Ru2(npc)2(L)2] (npc = 1,8-naphthyridine-2-carboxylate, L = acetylacetonate (acac) for 2, hexafluoroacetylacetonate (hfac) for 3, and 1,3-diphenyl-1,3-propanedionate (dppd) for 4), were successfully synthesized via solvothermal reactions of [Ru2(npc)2(O2CMe)2] (1) with the corresponding β-diketone ligands. Crystallographic analyses revealed that 2-4 commonly adopt half-paddlewheel-type structures, which feature (i) a direct Ru-Ru double bond (2.3671(2), 2.3742(4), and 2.3587(5) Å, respectively), (ii) two npc ligands bridging the Ru2 core in head-to-tail fashion, and (iii) two β-diketonate ligands chelating each Ru ion. Temperature-dependent magnetic susceptibility measurements revealed that 2-4 exhibit effective magnetic moments of 2.85, 2.75, and 2.80μB at 300 K, respectively, which are consistent with the spin-only value of 2.83μB for an S = 1 system, and large zero-field splitting parameters (D = 235, 345, and 235 cm-1, respectively), which are commonly observed for paddlewheel-type Ru24+ complexes. Spin-density distributions and molecular orbital analyses based on density functional theory (DFT) calculations clarified that (a) two magnetic spins in 2-4 are predominantly localized on the Ru24+ core, (b) the electronic configuration of the Ru2 core is commonly π4δ2σ2δ*2π*2, and (c) the LUMO(β)s of 2 and 4 are mainly derived from the π*(npc) orbitals, whereas that of 3 is primarily composed of the π*(Ru2)/π*(hfac) orbital. Electrochemical properties are strongly influenced by the β-diketonate ligands; 3 exhibits a markedly positive shift of the oxidation wave attributed to the Ru25+/Ru24+ redox couple compared with 2 and 4, owing to the strong electron-withdrawing effect of the hfac ligand. Furthermore, a Ru24+/Ru23+ redox couple was observed for 3 at -0.37 V, whereas the corresponding reduction waves were not detected for 2 and 4. The absorption spectra of 2 and 4 exhibit intense bands in the 550-750 nm region, which are attributed to MLCT transitions from the Ru2 moiety to the npc ligands, and are similar to that of 1. In contrast, the absorption bands of 3 observed in the 502-630 nm region, which are significantly blue-shifted by 50-120 nm relative to those of 2 and 4 due to the strong electron-withdrawing effect of the CF3 group in the hfac ligand, were assigned to MLCT transitions from the Ru2 core to the npc ligands as well as the hfac ligands based on time-dependent DFT calculations.

Single crystals of a Eu-based Zintl compound, Eu9Zn4.5As9, were synthesized by a flux method and characterized by single-crystal X-ray diffraction, magnetic measurements, heat capacity, and electrical transport. Eu9Zn4.5As9 crystallizes in an orthorhombic structure (space group Pnma) composed of a highly complex Zn-As polyanionic framework featuring multiple types of Zn coordination and partially occupied Zn sites. The presence of partially occupied Zn sites leads to deviations from ideal Zintl electron counting, resulting in metallic electrical transport. Magnetic susceptibility, isothermal magnetization, and heat capacity measurements reveal multiple magnetic transitions at low temperatures, including the development of a short-range ferromagnetic order below ∼15 K, a long-range antiferromagnetic transition at 11.3 K, and a further transition into a canted antiferromagnetic state at 6.8 K. In addition, a negative magnetoresistance of up to -40% is observed at low temperatures, reflecting a strong coupling between the Eu2+ moments and the itinerant charge carriers. These results demonstrate that Eu9Zn4.5As9 is a metallic Zintl compound with a structurally complex polyanionic framework and rich magnetic behaviors.