Browse Articles

Design of thin, wideband electromagnetic absorbers with polarization and angle insensitivity using deep learning

Abstract Metamaterial-based electromagnetic absorbers, despite being thin and lightweight, typically suffer from narrow-band frequency bandwidth and sensitivity to polarization and incident angle due to their resonant nature. Previous methods to increase bandwidth have shown improvements but have not fully succeeded in developing wide-band, thin metamaterial-based absorbers suitable for mass production. In this study, we introduce a novel approach that leverages artificial intelligence to design a thin, wideband metamaterial-based absorber covering the entire frequency range of 8-12 GHz. The proposed method utilizes a Generative Adversarial Network (GAN), given the need for precise structural details and computational efficiency, which globally outperform variational autoencoders (VAEs) and diffusion models, for parameter estimation and a Multi-Layer Perceptron (MLP) network as a simulator to predict the electromagnetic response of the designed absorber and provide feedback to the generative network. Numerical full-wave electromagnetic simulations serve as the training data and ground truth for both the GAN and MLP networks. This training enables the generative network to produce structures with high absorption, while the MLP predicts the corresponding absorbance value for each structure. This approach allows for the rapid design of various real-world structures, quick calculation of their absorption values using the MLP network, and selection of the most optimal structures for fabrication. The performance of the designed metamaterial-based absorber is verified both numerically and experimentally. Results show an absorption rate above 90% for all frequencies in the range of 8-12 GHz. The structure also operates effectively for both TE and TM polarizations and for all incident angles between 0-45 degrees. Additionally, the designed structure can be easily fabricated using printed circuit board (PCB) technology, making it practical and suitable for mass production.

Importance of the Ferryl Quintet State in Determining the Electronic Properties of P450 Compound I

Predicting intra-abdominal hypertension using anthropometric measurements and machine learning

High-Energy Density Li-Ion Battery Cathode Using Only Industrial Elements

Kv4.2 Regulates Basal Synaptic Strength by Inhibiting R-Type Calcium Channels in the Hippocampus

Kv4.2 subunits, which mediate transient A-type K + current, are crucial in regulating neuronal excitability and synaptic responses within the hippocampus. While their contribution to activity-dependent regulation of synaptic response is well-established, the impact of Kv4.2 on basal synaptic strength remains elusive. To address this gap, we introduced a Kv4.2-specific antibody (anti-Kv4.2) into hippocampal neurons of mice of both sexes to selectively inhibit postsynaptic Kv4.2, enabling direct examination of its impact on excitatory postsynaptic potentials (EPSPs) and currents (EPSCs) during basal synaptic activity. Our results demonstrated that blocking Kv4.2 significantly enhanced the amplitude of EPSPs. This amplification was proportional to the increase in the amplitude of EPSCs, which, in turn, correlated with the expression level of Kv4.2 in the dendritic regions of the hippocampus. Furthermore, the anti-Kv4.2–induced increase in EPSC amplitude was associated with a decrease in the failure rate of EPSCs evoked by minimal stimulation, suggesting that blocking Kv4.2 facilitates the recruitment of AMPA receptors to both silent and functional synapses to enhance synaptic efficacy. The anti-Kv4.2–induced synaptic potentiation was effectively abolished by intracellular 10 mM BAPTA or by blocking R-type calcium channels (RTCCs) and downstream signaling molecules, including protein kinases A and C. Importantly, Kv4.2 inhibition did not occlude further synaptic potentiation induced by high-frequency stimulation, suggesting that anti-Kv4.2–induced synaptic strengthening involves unique mechanisms that are distinct from long-term potentiation pathways. Taken together, these findings underscore the essential role of Kv4.2 in the regulation of basal synaptic strength, which is mediated by the inhibition of RTCCs.

Assessing creep and creep recovery performance of plastic processed aggregate based concrete

Amide-Based Cathode Interfacial Layer with Dual-Modification Mechanisms Enables Stable Organic Solar Cells with High Efficiency Achieving 20%

Enhanced novelty approaches for resource allocation model for multi-cloud environment in vehicular Ad-Hoc networks

Halogen Bond Strength in Solids Quantified via Zeeman-Perturbed Nuclear Quadrupole Resonance Spectroscopy

Metabolic phenotype of bovine blood-derived neutrophils is altered in milk

Abstract In a healthy udder, immune cells from the peripheral bloodstream migrate into mammary tissue in low numbers to provide baseline immune surveillance, without triggering inflammation. In bovine intramammary inflammation, on the other hand, high amounts of leukocytes are recruited, causing severe inflammation. We were interested in leukocyte subpopulations and functional differences between blood- and milk-derived neutrophils from healthy and inflamed udder quarters. In this context, we found a distinct leukocyte subpopulation profile dependent on the health status of mammary gland quarters, with a predominant T cells population in heathy mammary gland quarters and a shift to macrophages and granulocytes in inflammation. Further, we detected divergent expression of major histocompatibility complex class II and interleukin 2 receptor CD25 on the surface of milk- and blood-derived neutrophils, pointing to antigen presentation and immune modulatory properties. Moreover, we observed differences in production of reactive oxygen species, deviant early and late apoptosis and functional changes in these cells, pointing to an altered metabolic phenotype in milk cells dependent on the health status of mammary gland quarters. These findings provide insights into the functional adaptations of neutrophils in different environments, highlighting the importance of metabolic alterations for immune cell function.

Development and validation comparison of multiple models for perioperative neurocognitive disorders during hip arthroplasty

Kinetically Trapped Nanocrystals with Symmetry-Preserving Shapes

Modeling of sand-cultivated substrate for Gobi facility agriculture and validation of trenching test

Regulating Cell–Material Interfacial Interactions through Selective Cellular Resistance

Increased primary breast tumor expression of CD73 is associated with development of bone metastases and is a potential biomarker for adjuvant bisphosphonate use

Modular Access from Acrylate to a Sustainable Polyester Platform with Large-Span Tunability and Chemical Circularity under Mild Conditions

Oculomotor learning is evident during implicit motor sequence learning

Predicting coronavirus disease 2019 severity using explainable artificial intelligence techniques

Giant Enhancement of Optical Nonlinearity by Manipulating Guest Molecular Stacking Modes in Metal–Organic Frameworks

Characterizing Human Disparity Tuning Properties Using Population Receptive Field Mapping

Our visual percept of small differences in depth is largely informed by binocular stereopsis, the ability to decode depth from the horizontal offset between the retinal images in each eye. While multiple cortical areas are associated with stereoscopic processing, it is unclear how tuning to specific binocular disparities is organized across the human visual cortex. We used 3 T functional magnetic resonance imaging to generate population receptive fields (pRFs) in response to modulation of binocular disparity to characterize the neural tuning to disparity. We also used psychophysics to measure stereoacuity thresholds compared with backgrounds at different depths (pedestal disparity). Ten human participants (seven females) observed correlated or anticorrelated random-dot stereograms with disparity ranging from −0.3 to 0.3°, and responses were modeled as one-dimensional tuning curves along the depth dimension. First, we demonstrate that lateral and dorsal visual areas show the greatest proportion of vertices selective for binocular disparity. Second, with binocularly correlated stimuli, we show a polynomial relationship between preferred disparity and tuning curve width, with sharply tuned disparity responses at near-zero disparities, and broader disparity tuning profiles at near or far disparities. This relationship held across visual areas and was not present for anticorrelated stimuli. Finally, the individual thresholds for psychophysical stereoacuity at the three different pedestal disparities were broadly related to pRF tuning width in area V1, suggesting a possible limit for fine stereopsis at the earliest level of cortical processing. Together, these findings point to heterogeneity of disparity processing across human visual areas, comparable with nonhuman primates.