By covering a metal ground plane with a periodic surface texture, we can alter its electromagnetic properties. The impedance of this metasurface can be modeled as a parallel resonant circuit, with sheet inductance L, and sheet capacitance C. The reflection phase varies with frequency from + to , and crosses through 0 at the LC resonance frequency, where the surface behaves as an artificial magnetic conductor. By incorporating varactor diodes into the texture, we have built a tunable impedance surface, in which an applied bias voltage controls the resonance frequency, and the reflection phase. We can program the surface to create a tunable phase gradient, which can electronically steer a reflected beam over + 40 in two dimensions, for both polarizations. We have also found that this type of resonant surface texture can provide greater bandwidth than conventional reflectarray structures. This new electronically steerable reflector offers a low-cost alternative to a conventional phased array.

This paper proposes a novel depth-aware salient object detection and segmentation framework via multiscale discriminative saliency fusion (MDSF) and bootstrap learning for RGBD images (RGB color images with corresponding Depth maps) and stereoscopic images. By exploiting low-level feature contrasts, mid-level feature weighted factors and high-level location priors, various saliency measures on four classes of features are calculated based on multiscale region segmentation. A random forest regressor is learned to perform the discriminative saliency fusion (DSF) and generate the DSF saliency map at each scale, and DSF saliency maps across multiple scales are combined to produce the MDSF saliency map. Furthermore, we propose an effective bootstrap learning-based salient object segmentation method, which is bootstrapped with samples based on the MDSF saliency map and learns multiple kernel support vector machines. Experimental results on two large datasets show how various categories of features contribute to the saliency detection performance and demonstrate that the proposed framework achieves the better performance on both saliency detection and salient object segmentation.

In this report, a hand-held impulse-radar breast cancer detector is presented and the detectability of malignant breast tumors is demonstrated in the clinical test at Hiroshima University Hospital, Hiroshima, Japan. The core functional parts of the detector consist of 65-nm technology complementary metal-oxide-semiconductor (CMOS) integrated circuits covering the ultrawideband width from 3.1 to 10.6 GHz, which enable the generation and transmission of Gaussian monocycle pulse (GMP) with the pulse width of 160 ps and single port eight throw (SP8T) switching matrices for controlling the combination of 4 × 4 cross-shaped dome antenna array. The detector is designed to be placed on the breast with the patient in the supine position. The detectability of malignant tumors is confirmed in excised breast tissues after total mastectomy surgery. The three-dimensional positions of the tumors in the imaging results are consistent with the results of histopathology analysis. The clinical tests are conducted by a clinical doctor for five patients at the hospital. The malignant tumors include invasive ductal carcinoma (IDC) and ductal carcinoma in situ (DCIS). The final confocal imaging results are consistent with those of Magnetic Resonance Imaging (MRI), demonstrating the feasibility of the hand-held impulse-radar detector for malignant breast tumors.

Calcium phosphate cement (CPC) is a highly promising bone substitute and an excellent carrier for delivering growth factors. Yet, the lack of macro-porosity and osteoinductive ability, limit its use. This study is aimed at developing a novel biodegradable biomaterial for bone repair with both highly osteoconductive and osteoinductive properties. RhBMP-2 loaded PLGA microspheres were incorporated into rhBMP-2/CPC for macropores for bone ingrowth. The compressive strength, crystallinity, microscopic structure, and bioactivity of the composites were investigated. The results showed that with the incorporation of rhBMP-2 loaded PLGA microspheres, the compressive strength was decreased from (29.48+/-6.42) MPa to (8.26+/-3.58) MPa. X-ray diffraction revealed that the crystallinity pattern of HA formed by CPC had no significant change. Inside the composite, the microspheres distributed homogeneously and contacted intimately with the HA matrix, as observed by scanning electron microscopy (SEM). When the PLGA microspheres dissolved after having been emerged in PBS for 56 days, macropores were created within the CPC. The rhBMP-2/PLGA/CPC composite, showing a 4.9% initial release of rhBMP-2 in 24 h, followed by a prolonged release for 28 days, should have a greater amount of rhBMP-2 released compared to the CPC delivery system. When rabbit marrow stromal cells were cocultured with the composite, the alkaline phosphatase (ALP) and osteocalcin (OC) showed a dose response to the rhBMP-2 released from the composite, indicating that the activity of rhBMP-2 was retained. This study shows that the new composite reveals more rhBMP-2 release and osteogenic activity. This novel BMP/PLGA/CPC composite could be a promising synthetic bone graft in craniofacial and orthopedic repairs.

An ultrawideband (UWB) radar-based breast cancer detection system, which is composed of complementary metal-oxide-semiconductor integrated circuits, is presented. This system includes Gaussian monocycle pulse (GMP) generation circuits, switching (SW) matrix circuits, equivalent-time sampling circuits, and a compact UWB antenna array. During the detection process, the GMP signal with the center frequency of 6 GHz is first generated and transmitted with a repetition frequency of 100 MHz. The GMP signal is sent to a selected transmitter antenna by the SW matrix module, and the reflected signal is captured by the receiver antennas. Next, the high-speed equivalent-time sampling circuits are employed to retrieve the reflected GMP signal. A confocal algorithm is used to reconstruct the breast image. The total size for the prototype module is 45 cm × 30 cm × 14.5 cm in length, width, and height, respectively, which is dramatically smaller than the conventional detection systems. Using our proposed system, we demonstrate a successful detection of 1-cm cancer target in the breast phantom.INDEX TERMS Breast cancer, CMOS, microwave imaging, ultrawideband, confocal algorithm.