Development and validation of radiomics machine learning model based on contrast-enhanced computed tomography to predict axillary lymph node metastasis in breast cancer

Preoperative identification of axillary lymph node metastasis can play an important role in treatment selection strategy and prognosis evaluation. This study aimed to establish a clinical nomogram based on lymph node images to predict lymph node metastasis in breast cancer patients. A total of 193 patients with non-specific invasive breast cancer were divided into training (n = 135) and validation set (n = 58). Radiomics features were extracted from lymph node images instead of tumor region, and the least absolute shrinkage and selection operator logistic algorithm was used to select the extracted features and generate radiomics score. Then, the important clinical factors and radiomics score were integrated into a nomogram. A receiver operating characteristic curve was used to evaluate the nomogram, and the clinical benefit of using the nomogram was evaluated by decision curve analysis. We found that clinical N stage and radiomics score were independent clinical predictors. Besides, the nomogram accurately predicted axillary lymph node metastasis, yielding an area under the receiver operating characteristic curve of 0.95 (95% confidence interval 0.93-0.98) in the validation set, indicating satisfactory calibration. Decision curve analysis confirmed that the nomogram had higher clinical utility than clinical N stage or radiomics score alone. Overall, the nomogram based on radiomics features and clinical factors can help radiologists to predict axillary lymph node metastasis preoperatively and provide valuable information for individual treatment

Recent developments of metamaterials/metasurfaces for RCS reduction

In this paper, recent developments of metamaterials and metasurfaces for RCS reduction are reviewed, including basic theory, working principle, design formula, and experimental verification. Super-thin cloaks mediated by metasurfaces can cloak objects with minor impacts on the original electromagnetic field distribution. RCS reduction can be achieved by reconfiguring scattering patterns using coding metasurfaces. Novel radar absorbing materials can be devised based on field enhancements of metamaterials. When combined with conventional radar absorbing materials, metamaterials can expand the bandwidth, enlarge the angular range, or reduce the weight. Future tendency and major challenges are also summarized

Circulation of spoof surface plasmon polaritons: Implementation and verification

In this letter, we are dedicated to implementation and experimental verification of broadband circulator for spoof surface plasmon polaritons (SSPPs). For the ease of fabrication, a circulator operating in X band was firstly designed. The comb-like transmission lines (CL-TLs), a typical SSPP structure, are adopted as the three branches of the Y-junction. To enable broadband coupling of SSPP, a transition section is added on each end of the CL-TLs. Through such a design, the circulator can operate under the sub-wavelength SSPP mode in a broad band. The simulation results show that the insertion loss is less than 0.5dB while the isolation and return loss are higher than 20dB in 9.4-12.0GHz. A prototype was fabricated and measured. The experimental results are consistent with the simulation results and verify the broadband circulation performance in X band

Design of triple-band-pass frequency selective structure based on spoof surface plasmon polariton

In this paper, a triple-band-pass frequency selective structure is designed by combining traditional frequency selective surfaces (FSSs) with the spoof surface plasmon polariton (SSPP) guiding structure array. The FSSs consist of Jerusalem cross unit cell array with dual-band-pass property. And the SSPP guiding structure array is composed of vertical metallic blade structure array with high-efficiency transmission by engineering the dispersion of SSPP. By arranging the FSSs above the SSPP guiding structure array, a null located between the two passbands is introduced, resulting in a triple-band-pass characteristic. Furthermore, the triple-band-pass frequency selective structure is simulated, fabricated and measured. Both the simulated and measured results agree well, and verify that the transmissivities are all higher than -0.5dB in three frequency ranges: 2.42-2.90GHz, 5.57-5.85GHz and 9.48-9.85GHz. And the transmissivities of stopbands are lower than -10dB in three frequency ranges: 3.12-5.46GHz, 6.65-7.89GHz and 10.32-15.20GHz