RESUMEN
Concentric circular microphone arrays have been used in a wide range of applications, such as teleconferencing systems and smarthome devices for speech signal acquisition. Such arrays are generally designed with omnidirectional sensors, and the associated beamformers are fully steerable but only in the sensors' plane. If operated in the three-dimensional space, the performance of those arrays would suffer from significant degradation if the sound sources are out of the sensors' plane, which happens due to the incomplete spatial sampling of the sound field. This paper addresses this issue by presenting a new method to design concentric circular microphone arrays using both omnidirectional microphones and bidirectional microphones (directional sensors with dipole-shaped patterns). Such arrays are referred to as superarrays as they are able to achieve higher array gain as compared to their traditional counterparts with omnidirectional sensors. It is shown that, with the use of bidirectional microphones, the spatial harmonic components that are missing in the traditional arrays are compensated back. A beamforming method is then presented to design beamformers that can achieve frequency-invariant beampatterns with high directivity and are fully steerable in the three-dimensional space. Simulations and real experiments validate the effectiveness and good properties of the presented method.
RESUMEN
We investigate theoretically the impact of Rashba spin-orbit coupling (RSOC) effect to two-photon absorption (TPA) and its dependence on the polarization direction of the incident light in monolayer black phosphorus (BP) starting from an anisotropic two band k·p model. It is found that the TPA is enhanced several times by RSOC effect which is tuned by the external electric field. And the TPA response shows highly anisotropic, changing periodically with the polarization direction of incident linearly polarized light as the function of cos4θ approximatively. The TPA coefficient reaches its maximum when the polarization direction is aligned along the armchair direction (x-direction), while falls into its minimum along the zigzag direction (y-direction).
RESUMEN
Nucleotide-binding site and leucine-rich repeat (NLR) proteins are activated by detecting pathogen effectors, which in turn trigger host defenses and cell death. Although many NLRs have been identified, the mechanisms responsible for NLR-triggered defense responses are still poorly understood. In this study, through a genome-wide association study approach, we identified a novel NLR gene, Blast Resistance Gene 8 (BRG8), which confers resistance to rice blast and bacterial blight diseases. BRG8 overexpression and complementation lines exhibit enhanced resistance to both pathogens. Subcellular localization assays showed that BRG8 is localized in both the cytoplasm and the nucleus. Additional evidence revealed that nuclear-localized BRG8 can enhance rice immunity without a hypersensitive response (HR)-like phenotype. We also demonstrated that the coiled-coil domain of BRG8 not only physically interacts with itself but also interacts with the KNOX â ¡ protein HOMEOBOX ORYZA SATIVA59 (HOS59). Knockout mutants of HOS59 in the BRG8 background show enhanced resistance to Magnaporthe oryzae strain CH171 and Xoo strain CR4, similar to that of the BRG8 background. By contrast, overexpression of HOS59 in the BRG8 background will compromise the HR-like phenotype and resistance response. Further analysis revealed that HOS59 promotes the degradation of BRG8 via the 26S proteasome pathway. Collectively, our study highlights HOS59 as an NLR immune regulator that fine-tunes BRG8-mediated immune responses against pathogens, providing new insights into NLR associations and functions in plant immunity.
RESUMEN
The root mean square (RMS) of the surface electromyography (sEMG) signal can respond to neuromuscular function, which displays a positive correlation with muscle force and muscle tension under positive and passive conditions, respectively. The purpose of this study was to investigate the changes in muscle force and tension after multilevel surgical treatments, functional selective posterior rhizotomy (FSPR) and tibial anterior muscle transfer surgery, and evaluate their clinical effect in children with spastic cerebral palsy (SCP) during walking. Children with diplegia (n = 13) and hemiplegia (n = 3) with ages from 4 to 18 years participated in this study. They were requested to walk barefoot at a self-selected speed on a 15-m-long lane. The patient's joints' range of motion (ROM) and sEMG signal of six major muscles were assessed before and after the multilevel surgeries. The gait cycle was divided into seven phases, and muscle activation state can be divided into positive and passive conditions during gait cycle. For each phase, the RMS of the sEMG signal amplitude was calculated and also normalized by a linear envelope (10-ms running RMS window). The muscle tension of the gastrocnemius decreased significantly during the loading response, initial swing, and terminal swing (p < 0.05), which helped the knee joint to get the maximum extension when the heel is on the ground and made the heel land smoothly. The muscle force of the gastrocnemius increased significantly (p < 0.05) during the mid-stance, terminal stance, and pre-swing, which could generate the driving force for the human body to move forward. The muscle tension of the biceps femoris and semitendinosus decreased significantly (p < 0.05) during the terminal stance, pre-swing, and initial swing. The decreased muscle tension could relieve the burden of the knee flexion when the knee joint was passively flexed. At the terminal swing, the muscle force of the tibial anterior increased significantly (p < 0.05), which could improve the ankle dorsiflexion ability and prevent foot drop and push forward. Thus, the neuromuscular function of cerebral palsy during walking can be evaluated by the muscle activation state and the RMS of the sEMG signal, which showed that multilevel surgical treatments are feasible and effective to treat SCP.