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We investigate symmetric metric-affine theories of gravity with a Lagrangian containing all operators of dimension up to four that are relevant to free propagation in flat space. Complementing recent work in the antisymmetric case, we derive the conditions for the existence of a single massive particle with good properties, in addition to the graviton.

Digital rock physics has increasingly become an emerging field in which advanced numerical simulation and high-resolution imaging are combined to accurately predict rock properties. In this context, multiscale imaging is crucial for fully capturing the inherent heterogeneity of natural rocks. However, limitations in resolution and field of view (FOV) present significant challenges. Direct numerical simulations at large scales are often not computationally practical or may be too expensive. The compromise between FOV and resolution is particularly pronounced in the complex multiscale pore structures of porous rocks, including carbonates in particular. To address this issue, we propose an innovative machine learning technique that integrates multiscale imaging data at varying resolutions. For the rock sample, we used the imaging data published by Nabipour et al. (Adv Water Resour 104695, 2024) in three resolutions. Our approach employs an optimized neural network design combined with a transfer learning strategy, enabling the identification of complex cross-scale correlations that were previously unattainable with conventional methods. The results demonstrate that this multiscale neural network approach effectively estimates permeability by analyzing various aspects of pore morphology across different scales. In particular, we achieved high accuracy, as evidenced by R-squared coefficients of 0.966 for training and 0.836 for testing in low-resolution domains, and also significantly enhanced computational efficiency, reducing the overall computational time. Despite being tested for images of carbonate rocks, the developed method is adaptable to a wide range of multiscale porous materials and offers a promising solution to the persistent challenge of balancing imaging resolution with FOV.

Fragile X syndrome is the most common inherited form of intellectual disability and is caused by the transcriptional silencing of the Fmr1 gene and the lack of fragile X messenger ribonucleoprotein (FMRP). FMRP is an RNA-binding protein that regulates the synthesis of synaptic proteins which are essential for proper brain function. Although circuit hyperexcitability is a hallmark of fragile X syndrome (FXS), the cell-autonomous effects of FMRP deficiency remain poorly understood. In this work, we investigated the functional consequences of the absence of FMRP on neuronal morphology and on ionotropic glutamate receptor surface distribution, using primary cultures of mice hippocampal neurons isolated from wild-type (WT) and Fmr1 knock-out (KO) pups. MAP2 staining of Fmr1 KO neurons showed a decrease in total dendritic length and complexity of the dendritic tree, accompanied by an increase in soma size compared to WT neurons. Moreover, immunolabelling of surface glutamate receptors performed under non-permeabilising conditions showed that Fmr1 KO neurons presented a higher content of synaptic surface GluN2A and a lower content of GluN2B subunits of NMDA receptors, while GluA1 and GluA2 distribution remained unchanged. Finally, multielectrode array data showed that Fmr1 KO neurons presented reduced spontaneous activity compared to control neurons. These data support the hypothesis that at the cellular level, Fmr1 KO hippocampal neurons are less excitable due to altered input processing, driven by structural defects and altered GluN2A expression in the synaptic plasma membrane.

Gadolinium and manganese-doped zinc tungstate (ZnWO₄: Gd & ZnWO₄: Mn (1 at%)) nanocrystals were successfully prepared using a simple co-precipitation method. The structural, morphological, and chemical properties of the materials were thoroughly investigated using X-ray diffraction (XRD), scanning/transmission electron microscopy (SEM/TEM), and energy dispersive X-ray (EDX) analysis. The crystallite sizes of the Gd-doped and Mn-doped samples were 46 nm and 59 nm, respectively. XRD analysis confirmed that both samples exhibited a single monoclinic phase crystal structure. The Gd-doping resulted in a more uniform particle size distribution and smoother surface morphology, which could enhance the optical and magnetic properties of the material. In contrast, Mn-doping led to the formation of more agglomerated particles with a rougher texture, potentially affecting the specific surface area and its interaction with external fields. SEM/TEM images also revealed an increase in average particle size with the Mn dopant. Optical properties, as measured by diffuse reflectance spectroscopy (DRS), showed a band gap of 3.79 eV for ZnWO₄: Gd and 3.40 eV for ZnWO₄: Mn. Magnetic measurements indicated enhanced magnetic properties for ZnWO₄: Mn compared to both pure ZnWO₄ and ZnWO₄: Gd. The dielectric properties, including the dielectric constant (εr), dielectric loss (tan δ), and AC conductivity, were studied over a frequency range from 100 Hz to 3 MHz at room temperature. The reduced coercivity observed in the Mn-doped sample suggests improved performance for potential applications in transformers, windings, and magnetic storage devices, where reduced core loss and enhanced efficiency are key requirements.This study not only enhances the understanding of the influence of Gd and Mn doping on ZnWO₄ properties but also opens up new possibilities for the development of multifunctional materials for advanced technological applications.

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A novel electrochemical biosensor for the detection of lead ions (Pb²⁺) with improved specificity and sensitivity was developed. The sensor design incorporated molecular imprinting technology, where chitosan was polymerized on the electrode surface to form a lead-specific cavity structure, thereby enhancing selectivity in complex sample matrices. Meanwhile, the tetrahedral DNA nanostructure was employed as the recognition probe to mitigate the entanglement issues commonly associated with single-stranded DNA, thus improving the sensitivity of the detection. The developed sensor exhibited a linear dynamic range from 0.050 to 2.000 μg/mL, with a limit of detection (LOD) of 0.0034 μg/mL. The aptasensor’s efficacy was verified through the analysis of aquatic samples, demonstrating a high degree of reliability comparable to that of inductively coupled plasma mass spectrometry (ICP-MS).

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The exceptional performance of Fe-based nanocrystalline alloys is well-recognized, however, the regulation of their microstructure remains a noteworthy concern. This study aims to maintain a fixed Fe content while optimizing the composition of the Fe_80.5B_9.5+xP₈Cu_1.5-xNb_0.5 alloys (x = 0, 0.4, & 0.8 at%) by substituting Cu with extra B. The microstructural evolution of these alloys with varying Cu content during two-step annealing and its influence on magnetic properties have been systematically investigated using XRD, DSC, and Mössbauer spectroscopy techniques. The Mössbauer spectra results reveal that the microstructural evolution of alloys with varying Cu content is significantly impacted by relaxation. Additionally, a model is proposed to describe the evolution of nanostructures in alloys with varying Cu content during two-step annealing. Notably, the alloy with an optimized Cu addition (1.1 at.%) exhibits a refined nanostructure and enhanced soft magnetic properties (B_s = 1.82 T, H_c = 5.66 A/m) after two-step annealing.

Hierarchically porous activated carbons (HACs) were derived from expired tablets through facile carbonization with the aid of H₃PO₄ activation. The enhanced specific surface area (SSA) and porous architecture of the derived ACs were confirmed using standard characterization techniques. The as-prepared HACs exhibited an improved specific capacitance (CS) of 141.8 F/g at 2 A/g, with a cyclability of 70% after 2,000 repeated charge–discharge cycles. The HACs//HACs symmetric supercapacitor (SC) device demonstrated a CS of 46.8 F/g at 2 A/g. Additionally, the HACs//HACs symmetric device exhibited the highest energy density of 12.7 Wh/kg and a power density of 4656.5 W/kg. The HACs//HACs device also displayed exceptional cyclability, maintaining 80.2% retention after 3,000 charge/discharge cycles at 20 A/g. Furthermore, the photocatalytic activity of both ACs and HACs was assessed under visible light through the photodegradation of Reactive Black 5 (RB5) dye in aqueous solution. The results indicated that the HACs exhibited excellent photocatalytic activity, with approximately 80% degradation after 120 min, compared to the ACs. These findings demonstrate that the HACs electrode is a cost-effective, eco-friendly, and promising candidate for high-performance energy storage applications.