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The attention network test (ANT), developed based on the triple‐network taxonomy by Posner and colleagues, has been widely used to examine the efficacy of alerting, orienting and executive control in clinical and developmental neuroscience studies. Recent research suggests the imperfect reliability of the behavioural ANT and its variants. However, the classical ANT fMRI task's test–retest reliability has received little attention. Moreover, it remains ambiguous whether the attention‐related intrinsic network components, especially the dorsal attention, ventral attention and frontoparietal network, manifest acceptable reliability. The present study approaches these issues by utilizing an openly available ANT fMRI dataset for participants with Parkinson's disease and healthy elderly. The reproducibility of group‐level activations across sessions and participant groups and the test–retest reliability at the individual level were examined at the voxel, region and network levels. The intrinsic network was defined using the Yeo‐Schaefer atlas. Our results reveal three critical facets: (1) the overlapping of the group‐level contrast map between sessions and between participant groups was unsatisfactory; (2) the reliability of alerting, orienting and executive, defined as a contrast between conditions, was worse than estimates of specific conditions. (3) Dorsal attention, ventral attention, visual and somatomotor networks showed acceptable reliability for the congruent and incongruent conditions. Our results suggest that specific condition estimates might be used instead of the contrast map for individual or group‐difference studies. [ABSTRACT FROM AUTHOR]

To address the increasing demand for high microwave‐absorbing performance, new polarization‐response wave‐absorbing metamaterials are developed herein inspired by the microstructure of locust compound eyes by employing bionics and optimization principles. The materials overcome a common limitation of wave‐absorbing metamaterials, wherein the performance substantially decreases with changes in the polarization mode, enabling the broadband absorption for x and y polarizations. The designed bioinspired materials have various shapes of structural units, triggering a multifrequency point response mechanism that effectively improves the wave‐absorbing performance. Experimental and simulation results show that the designed materials can form different equivalent circuits based on structural and polarization differences, influencing the overall wave‐absorbing performance. They exhibit an effective absorption bandwidth of ≈12 GHz (reflection loss < −10 dB) for x or y polarizations at a thickness of 2 mm. This study provides a typical example for future research on wave‐absorbing metamaterials with polarization‐response characteristics. [ABSTRACT FROM AUTHOR]

There is an urgent need to develop microwave absorbing materials with ultra‐broadband absorption and multiband stealth compatibility, but this is difficult to achieve due to the difficulty of perfect electromagnetic impedance matching. Therefore, inspired by the anti‐reflection moth eye model, this article prepares carbonyl iron (CIP)/polyurethane (PU) absorbing materials into three biomimetic structures of cylinder, circular cone, and semi‐ellipsoid structures to optimize the absorption performance, which realizes the effective absorption of 5.13–18 GHz. The simulation models proved that the biomimetic structures can improve the anti‐reflection performance by building gradient impedance inside the materials. Finally, under the synergistic action of multiple reflection and gradient impedance mechanisms, the effective absorption bandwidth (EAB) of the semi‐ellipsoid moth eye biomimetic structure material with a total thickness of 3 mm can reach 6.94 GHz. The material can still achieve the EAB of 6.84 GHz with a low infrared emissivity of 0.242 by constructing the double‐layer structure. This work effectively solves the problem that the EAB of traditional microwave absorbing materials is difficult to be broadened due to impedance mismatch, and puts forward a new idea for optimizing the performance of microwave absorbing materials and compatible stealth. [ABSTRACT FROM AUTHOR]

Recently, high‐entropy alloy (HEA) microwave‐absorbing materials have attracted extensive attention. Herein, a double‐layer structure consists of a low‐infrared emission metasurface and a FeCoNiMn0.5Si0.5Al0.5 HEA coating with enhanced microwave absorption performance is designed. The upper metasurface consisting of periodic hexagonal aluminum structural unit has excellent low‐infrared emission properties, while enabling selective transmission and absorption enhancement of radar waves. The emissivity of the low‐infrared emitting layer is lower than 0.2, and the metastructure on its surface affects more on the high‐frequency absorption performance. The bottom layer made of HEA coating with 1 mm hexagonal etching structure has an effective absorption bandwidth of 2.8 GHz, and its reflection loss (RL) can reach −42 dB. There is a certain fit relationship between the unit size of the periodic structure and the absorption performance of the underlying coating. For the coatings with high‐frequency RL peaks, a larger unit size of the periodic structure will lead to an obvious improvement on the absorption performance. A broad application prospect for multiband compatibility stealth is provided. [ABSTRACT FROM AUTHOR]

Objectives: Respiratory syncytial virus (RSV) is a leading cause of lower respiratory tract infection in young children. We aimed to analyze the factors affecting the estimation of RSV‐related disease burden, and to provide evidence to help establish a surveillance system. Methods: We searched the English‐ and Chinese‐language databases for articles published between January 1, 2010 and June 2, 2022. The quality of the included articles was assessed using the Agency for Healthcare Research and Quality scale. Random‐effects models were used for data synthesis and subgroup analyses. This review was registered in the Prospective Register of Systematic Reviews (PROSPERO: CRD42022372972). Results: We included 44 studies (149,321,171 participants), all of which were of medium or high quality. The pooled RSV‐related disease incidence, hospitalization rate, in‐hospital mortality, and overall mortality rates in children aged 5 years and younger were 9.0 per 100 children per year (95% confidence interval [CI]: 7.0–11.0), 1.7 per 100 children per year (95% CI: 1.3–2.1), 0.5 per 100 children per year (95% CI: 0.4–0.5), and 0.05 per 100 children per year (95% CI: 0.04–0.06), respectively. Age, economics, surveillance types, case definition, and data source were all recognized as influencing factors. Conclusions: A standardized and unified RSV surveillance system is required. Case definition and surveillance types should be fully considered for surveillance of different age groups. [ABSTRACT FROM AUTHOR]

In view of the practical demands and mechanistic conflicts between microwave absorption and heat shielding compatibility, a double‐layer composite coating based on moth‐eyed hexagonal anti‐reflective structure is prepared by combining the advantages of metamaterials and coatings. The hexagonal periodic sequential configuration of the upper infrared shield layer (IRSL) can break the continuity of the electric field, induce a networked concentration of the surface current and internal electric field of the microwave absorption layer, thus optimizing the impedance matching and counteract the attenuated absorption performance due to the high dielectric IRSL. In addition, the emissivity of IRSL can be tuned artificially by changing the filler composition and particle size. The structural double‐layer composite coatings have a maximum effective absorption (reflection loss←10 dB) bandwidth of 7.4 GHz in the SKu bands at deep subwavelength thickness, while the infrared emissivity is 0.292. This work provides a novel approach for multispectral modulation in the field of advanced compatible protection systems. [ABSTRACT FROM AUTHOR]

Polarization conversion of chiral ordered structures can achieve effective electromagnetic attenuation through flexible field rotation. However, the mechanism of near‐field coupling generation on which it depends remains unclear, hindering the development of chiral wave‐absorbing materials. In this work, a beetle‐inspired ordered structure, which is a kind of chiral metamaterials (CMMs) consisting of high entropy alloy (HEA) electromagnetic dissipative unit and media‐layer, is rationally designed. Such CMMs show that the coupling and decoupling effects can achieve dynamic conversion between linearly polarized waves and circularly polarized waves, and the mechanisms analyzed and verified by simulation models confirm that as a universal method. The fabricated biomimetic metamaterials show desirable absorption with effective absorption bandwidth of 4.48 GHz at 2 mm interlayer medium thickness (≥75% absorptivity, reflection loss ≤ −6 dB) and minimum reflection loss (RLmin) of −53.6 dB. Moreover, pasting the flexible CMMs conformally on conventional coating surfaces can boost microwave‐invisible capacity, whose absorption bandwidth with RL lower than −6 dB increases to 5.18 GHz over HEA coating. In short, this work elucidates the mechanism of chiral near‐field coupling and provides a novel solution principle and methodology for using CMMs in wave‐absorbing materials. [ABSTRACT FROM AUTHOR]

Derived from the increasing demand for radar and infrared camouflage integration, a two‐layer hierarchical structure that combines coating and a square patch‐based metasurface is designed. Under deep subwavelength thickness, the infrared stealth layer (IRSL) can markedly reinforce microwave absorption layer (MAL) performance. More than 90% of the electromagnetic wave energy in the 3.7–5.1 GHz and 12.8–18 GHz bands can be absorbed. The hierarchical structure expands the effective absorption bandwidth of the exposed coatings from 0 to 6.6 GHz, and the maximum reflection loss increases from −8 to −40 dB. Moreover, the emissivity in the midinfrared range is maintained at an extremely low value of 0.281. The delay of magnetic resonance is found in the simulation model, indicating that strong magnetic resonance is formed in coatings after covering the IRSL. Meanwhile, the absorption peaks of the coatings are controlled by low‐pass filter metasurfaces. These two factors contribute to the enhancement effect of IRSL on MAL and break the boundary between radar and infrared stealth. Herein, an original solution for tuning multispectral electromagnetic (EM) waves is provided and it has broad application prospects in advanced compatible camouflage material. [ABSTRACT FROM AUTHOR]

Chirality, in which electromagnetic characteristic promotes asymmetric polarization, is expected to realize broadband absorption for microwave absorption materials (MAMs). Herein, inspired by the microstructure of nepenthes, a scalable approach is reported for fabricating hierarchical‐chiral helical carbon fibers with broadband microwave absorption as well as multispectral chiral manipulation. The chiral potential barriers are established by applying helically distributed stress to the fiber, which induce helical electric dipoles via positive and negative charges accumulated at the potential barriers. The states of polarization loss by Debye relaxation are 2, 3, and 4 in the samples with achirality, single‐chirality, and dual‐chirality, respectively; the polar vector of achiral electric dipoles is transformed into pseudovectors through chiral potential barriers to improve the synergistically magnetic loss, and the grade of chirality is quantified based on symmetry breaking theory. The single‐chiral fibers reach strongest absorption peak value of −30.67 dB at 2.96 GHz (carbon content is 50 wt%), and the dual‐chiral fibers achieve effective absorption bandwidth (RL ≤ −10 dB) of 8.8–18 GHz. In addition to microwaves, the chiral photonic manipulation plays a role in near‐ultraviolet and visible spectra. The present discovery points to a pathway for using chiral model to open up new microwave absorption mechanism and integrated application. [ABSTRACT FROM AUTHOR]

Despite great efforts in material design and modification, there are still obstacles to improve the effective microwave absorption, which hinders the development of stealth materials. By introducing a magnetically induced Huygens' metasurface with Fibonacci spiral meta‐atom, a hierarchical absorber with carbonyl iron particle coating is designed and prepared, of which the total effective absorption bandwidth (EAB, reflection loss ≤−10 dB) amazingly reaches 9.41 GHz, exceeding 199% of the original coatings', and the absorption peak value declines from −15.91 to −32.12 dB. The overall thickness of the absorber is 7 mm, only 0.17 over the minimum thickness dictated by the causality limit. A conceptual basis for the proposed design is provided, that is, the balance of effective surface current and magnetic current induced simultaneously will enhance the electromagnetic (EM) wave transmission, which contributes to broadening the absorption bandwidth with promising impedance matching. The system is validated numerically and experimentally, suggesting a novel route to obtain high‐performance microwave absorption materials for the EM stealth technology. [ABSTRACT FROM AUTHOR]

Rician noise reduction is an essential issue in magnetic resonance imaging (MRI). Recently, learning‐based methods have achieved great success in dealing with image restoration problems, which provide fast inference and good performance. One limitation of these methods, however, is that the training procedure is usually noise‐level dependent, i.e. the trained models are bound to a specific noise level and lack the ability to automatically adapt to different noise levels. In this study, the authors propose a variational model for Rician noise removal by integrating a noise adaption function into the field of experts image prior, which can adapt to different noise levels. Instead of directly solving the energy minimisation problem, the authors unroll the gradient descent step of the energy functional for several iterations, the time‐dependent parameters of which can be learned through a supervised training process. The authors call this methodology as the noise adaptive trainable non‐linear reaction–diffusion model. The proposed methodology is robustness against noise level changing and noise distributions. Experimental results over T1‐, T2‐ and PD‐weighted MRI data set demonstrate that the proposed model can achieve superior performance compared with other methods in terms of both the peak signal‐to‐noise ratio and the structural similarity index. [ABSTRACT FROM AUTHOR]

Dielectric composites based on polybasic components with hierarchical structures have promising potentials for electromagnetic absorber. However, strategy to strengthen coupling of transition metal oxides still demands to be optimized to enhance electromagnetic loss. Herein, inspired by the hierarchical structure of balsam pear, ultrafine ZnO is uniformly distributed and tightly capped in MnO2 by self‐assembly hydrothermal method. The unique hierarchical structure provides abundant polarization centers with large specific surface area. The compositions promote attenuation performance of electromagnetic waves, enhance relative permittivity and satisfy impedance matching as compared with that of pure ZnO or MnO2. The effective bandwidth (RL< −10 dB) reaches 5.93 GHz obtained with thin thickness of 1.8 mm. The effective bandwidth reaches 15 GHz via regulating their thickness. The fabricated MnO2/ZnO composites can achieve great adaptability in microwave. MnO2/ZnO composites keep stability even heated 700 °C in air. The phase and weight remain unchanged. The proposed interfacial modulation strategy can provide new opportunities for the design of efficient electromagnetic absorber with thermal stability. [ABSTRACT FROM AUTHOR]

Electromagnetic wave loss caused by rotating polarization of chiral structures has long been considered as a disadvantage in transmission, detection, etc., however, it can be turned to benefit in microwave absorbing materials to enhance absorption. Herein, inspired by the chiral structure of jeweled beetles, gyrotropic metamaterials (MMs) are designed and prepared, and experimentally demonstrate the enhanced microwave absorption by rotating polarization; the bandwidth of absorptivity greater than 80% (reflection loss, RL ≤ −7 dB) covers the entire 4–18 GHz frequency range under an ultralow surface density of 1.45 kg m−2; the mechanism analyzed and verified by simulation models demonstrates this a universal method. A new paradigm of MMs fabricated by high entropy alloy (HEA) is offered in this work, which increases the freedom of MM design and promotes the integration of material science and physics. Multifarious wave adaptability and multifunctionality achieved by integrated HEA unit cell and foamed polyurethane realize ultrasonic and water wave absorption, as well as impact and corrosion resistance. These designs hold great promise for facilitating functionally integrated materials for stealth technology, antiterrorist, encryption, sensing, and photon detection. [ABSTRACT FROM AUTHOR]

The article focuses on a study which examined the synthesis of fine nickel particles with sphere-like architecture through a wet chemical route in distilled water. Results of the study showed that there was a direct correlation between the shielding effectiveness values of two kinds of nickel-containing resin-based composites and nickel filler loading. The study also found that there is a tendency for fine nickel particles to aggregate for the purpose of decreasing surface energy.