165 research outputs found
Differentiable SAR Renderer and SAR Target Reconstruction
Forward modeling of wave scattering and radar imaging mechanisms is the key
to information extraction from synthetic aperture radar (SAR) images. Like
inverse graphics in optical domain, an inherently-integrated forward-inverse
approach would be promising for SAR advanced information retrieval and target
reconstruction. This paper presents such an attempt to the inverse graphics for
SAR imagery. A differentiable SAR renderer (DSR) is developed which
reformulates the mapping and projection algorithm of SAR imaging mechanism in
the differentiable form of probability maps. First-order gradients of the
proposed DSR are then analytically derived which can be back-propagated from
rendered image/silhouette to the target geometry and scattering attributes. A
3D inverse target reconstruction algorithm from SAR images is devised. Several
simulation and reconstruction experiments are conducted, including targets with
and without background, using both synthesized data or real measured inverse
SAR (ISAR) data by ground radar. Results demonstrate the efficacy of the
proposed DSR and its inverse approach
Upregulation of NUAK2: A novel prognostic marker in breast cancer
Background. Breast cancer is the most
commonly diagnosed neoplasm in women worldwide.
New molecular biomarkers and effective prognostic
models are being developed. This study aimed to
investigate the clinical and prognostic significance of
NUAK2 expression in patients with breast cancer.
Methods. The expression of NUAK 2 was examined
in breast cancer cells and tissues by real-time PCR,
western blotting, and immunohistochemical staining.
CCK-8 and colony formation assays were performed to
verify the effect of NUAK2 on the proliferation and
tumor progression of breast cancer cells. A tumor
formation assay in nude mice was performed to analyze
the effect of NUAK2 on the tumorigenicity of breast
cancer cells.
Results. The expression of NUAK2 in breast cancer
tissues was higher than that in paracarcinoma and
normal breast tissues. The overall survival of patients
with high NUAK2 expression was significantly lower
than that of patients with low NUAK2 expression.
Multivariate analyses indicated that NUAK2 was an
independent prognostic indicator of survival in breast
cancer. In vitro experiments demonstrated that knocking
down NUAK2 in breast cancer cells inhibited cell
proliferation and tumor-forming ability, and overexpression of NUAK2 showed the opposite effects.
NUAK2 overexpression promoted the tumorigenicity of
breast cancer cells in vivo.
Conclusion. These findings suggest that NUAK2 is
involved in breast cancer development and progression.
NUAK2 may be a valuable prognostic indicator in
patients with breast cancer
YOLO-SCL: a lightweight detection model for citrus psyllid based on spatial channel interaction
Efficient and accurate detection and providing early warning for citrus psyllids is crucial as they are the primary vector of citrus huanglongbing. In this study, we created a dataset comprising images of citrus psyllids in natural environments and proposed a lightweight detection model based on the spatial channel interaction. First, the YOLO-SCL model was based on the YOLOv5s architecture, which uses an efficient channel attention module to perform local channel attention on the inputs in the recursive gated convolutional modules to achieve a combination of global spatial and local channel interactions, improving the model’s ability to express the features of the critical regions of small targets. Second, the lightweight design of the 21st layer C3 module in the neck network of the YOLO-SCL model and the small target feature information were retained to the maximum extent by deleting the two convolutional layers, whereas the number of parameters was reduced to improve the detection accuracy of the model. Third, with the detection accuracy of the YOLO-SCL model as the objective function, the black widow optimization algorithm was used to optimize the hyperparameters of the YOLO-SCL model, and the iterative mechanism of swarm intelligence was used to further improve the model performance. The experimental results showed that the YOLO-SCL model achieved a [email protected] of 97.07% for citrus psyllids, which was 1.18% higher than that achieved using conventional YOLOv5s model. Meanwhile, the number of parameters and computation amount of the YOLO-SCL model are 6.92 M and 15.5 GFlops, respectively, which are 14.25% and 2.52% lower than those of the conventional YOLOv5s model. In addition, after using the black widow optimization algorithm to optimize the hyperparameters, the [email protected] of the YOLO-SCL model for citrus psyllid improved to 97.18%, making it more suitable for the natural environments in which citrus psyllids are to be detected. The experimental results showed that the YOLO-SCL model has good detection accuracy for citrus psyllids, and the model was ported to the Jetson AGX Xavier edge computing platform, with an average processing time of 38.8 ms for a single-frame image and a power consumption of 16.85 W. This study provides a new technological solution for the safety of citrus production
Fabrication of long-life quasi-solid-state Na-CO2 battery by formation of Na2C2O4 discharge product
Rechargeable Na-CO2 batteries are promising energy-storage devices due to their high energy density, environmental friendliness, and cost effectiveness. However, the insulating nature and irreversibility of the Na2CO3 discharge product cause large polarization and poor cyclicity. Here, we report a reversible quasi-solid-state Na-CO2 battery that is constructed by the synergistic action of a Co-encapsulated N-doped carbon framework catalyst and gel electrolyte to ensure the formation of a highly reversible Na2C2O4 discharge product. Experiments and density functional theory calculations indicate that the electron-agglomeration effect of Co nanoparticles enhances CO2 adsorption and lowers energy barrier, as well as promotes Na2C2O4 generation. A gel electrolyte containing an imidazole organic cation is used to inhibit the decomposition of the thermodynamically unstable Na2C2O4. The fabricated Na-CO2 battery exhibits a high discharge capacity of 3,094 mAh g^-1, a high-rate performance of 1,777 mAh g^-1 at a current density of 0.5 mA cm^-2, and excellent cycling performance of 366 cycles (2,200 h)
- …