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As a representative technique in electronics, the Smith Chart provides a fast, less‐computation, and graphical approach to solve the problems related to impedance matching. In this paper, we transplanted the Smith Chart into the design and analysis of a microwave metamaterial absorber (meta‐absorber) to develop an analytical and graphical approach for impedance matching of electromagnetic wave absorption. Before the structural design, four traces on the Smith Chart plane from the load to arrive at the impedance matching point (the center of the Smith Chart) can be graphically found to obtain perfect absorption. Then, we have designed four impedance matching circuit networks made of resistance, inductance, and capacitive elements and transmission lines to fit the four traces. Then, the matching circuits are mapped into the meta‐absorber structure by using three types of proposed layers. The full simulation method based on the finite element method is used to verify the proposed concept. Furthermore, an external dielectric loading strategy has been developed to achieve good angular stability up to 60° for the radar cross section reduction under transverse electric and transverse mangetic polarization incidence. The proposed method may provide a convenient way for various microwave devices, such as antennas. [ABSTRACT FROM AUTHOR]

Background: Due to inconsistent positioning, tumor shrinking, and weight loss during fractionated treatment, the initial plan was no longer appropriate after a few fractional treatments, and the patient will require adaptive helical tomotherapy (HT) to overcome the issue. Patients are scanned with megavoltage computed tomography (MVCT) before each fractional treatment, which is utilized for patient setup and provides information for dose reconstruction. However, the low contrast and high noise of MVCT make it challenging to delineate treatment targets and organs at risk (OAR). Purpose: This study developed a deep‐learning‐based approach to generate high‐quality synthetic kilovoltage computed tomography (skVCT) from MVCT and meet clinical dose requirements. Methods: Data from 41 head and neck cancer patients were collected; 25 (2995 slices) were used for training, and 16 (1898 slices) for testing. A cycle generative adversarial network (cycleGAN) based on attention gate and residual blocks was used to generate MVCT‐based skVCT. For the 16 patients, kVCT‐based plans were transferred to skVCT images and electron density profile‐corrected MVCT images to recalculate the dose. The quantitative indices and clinically relevant dosimetric metrics, including the mean absolute error (MAE), structural similarity index measure (SSIM), peak signal‐to‐noise ratio (PSNR), gamma passing rates, and dose‐volume‐histogram (DVH) parameters (Dmax, Dmean, Dmin), were used to assess the skVCT images. Results: The MAE, PSNR, and SSIM of MVCT were 109.6 ± 12.3 HU, 27.5 ± 1.1 dB, and 91.9% ± 1.7%, respectively, while those of skVCT were 60.6 ± 9.0 HU, 34.0 ± 1.9 dB, and 96.5% ± 1.1%. The image quality and contrast were enhanced, and the noise was reduced. The gamma passing rates improved from 98.31% ± 1.11% to 99.71% ± 0.20% (2 mm/2%) and 99.77% ± 0.18% to 99.98% ± 0.02% (3 mm/3%). No significant differences (p > 0.05) were observed in DVH parameters between kVCT and skVCT. Conclusion: With training on a small data set (2995 slices), the model successfully generated skVCT with improved image quality, and the dose calculation accuracy was similar to that of MVCT. MVCT‐based skVCT can increase treatment accuracy and offer the possibility of implementing adaptive radiotherapy. [ABSTRACT FROM AUTHOR]

The presence of protease inhibitors in a carbonated shell is intriguing and opens questions about their potential role in shell biomineralization. Our previous proteome study detected an epididymal protease inhibitor (eppin) which was strongly expressed in pearl nacre. Herein, we obtained the full-length complementary DNA sequence of eppin from Hyriopsis cumingii. The expression of eppin was localized to the dorsal epithelial cells of the mantle pallium and mantle center and significantly increased during pearl nacre deposition and shell nacreous layer regeneration. These results indicated that eppin is essential for nacre biomineralization. The expression of eppin was significantly increased at 3 h after Staphylococcus aureus challenge. GST-eppin could significantly inhibit the growth of S. aureus and effectively inhibit chymotrypsin activity. Inhibition of eppin in extrapallial fluid induced haphazard distribution of nanoscale grains and the destruction of the organic framework of the nacreous layer. These results indicated that eppin had a long-lasting antibacterial activity and provided a matrix protecting system that prevented extracellular degradation of matrix proteins. In addition, GST-eppin affected morphology regulation and induced the acceleration of calcium carbonate deposition. These results added to our understanding of the mode of action of protease inhibitors and their roles in shell biomineralization. [ABSTRACT FROM AUTHOR]

Objective: To analyze the relationship between 24‐h movement behaviors and adolescents' physical fitness, with sex difference and age disparity explored specifically. Methods: A total of 135 852 Chinese adolescents aged 13–22 years were included in this cross‐sectional study. Self‐reported 24‐h movement behavioral times, including moderate to vigorous physical activity (MVPA), recreational screen, and sleep, were identified as meeting guidelines based on Canadian recommendations. Physical fitness indicator (PFI) was calculated through sex‐ and age‐specific z scores of body mass index, forced vital capacity, 50 m dash, sit‐and‐reach, standing long jump, body muscle strength, and endurance running, and then classified as: low level (<20th), middle level (20th–80th), and high level (>80th). Mixed effect logistic regression was applied to analyze the association, and interaction terms were constructed to prove the sex and age disparities. Results: Only 12.4% of adolescents aged 13–22 years met all three recommendations. The number of meeting guidelines exhibited a typical dose–response relationship with high level PFI (OR = 1.22 [95% CI: 1.19–1.25]), and in detail, meeting MVPA + recreational screen (OR = 2.29 [95% CI: 2.09–2.51]) or MVPA‐only (OR = 2.16 [95% CI: 1.93–2.41]) guidelines were better associated with high‐level PFI. Besides, meeting MVPA‐only guideline was proved with stronger association with high‐level PFI for boys (p‐interaction = 0.005). The dose–response relationship in boys of the number of guidelines met with PFI was stronger in 19‐ to 22‐year‐olds (p‐interaction <0.001) and 16‐ to 18‐year‐olds (p‐interaction = 0.001) than that in 13‐ to 15‐year‐olds. Conclusion: The prevalence of meeting 24‐h movement behaviors guidelines among Chinese adolescents aged 13–22 years was relatively low. It was associated with adolescents' physical fitness, with meeting MVPA + recreational screen or MVPA‐only guidelines bringing greater benefits, and sex difference and age disparity existing. [ABSTRACT FROM AUTHOR]