We present our experimental set-up and results for a THz beam profiling system based on a mechanical spatial light modulator (SLM) for one pixel sensing. By placing a synthetic aperture into the path ...of a propagating THz beam we achieved the optical ON/OFF keying of its various intensity components. Further, by successively expose a series of predesigned binary masks we manage to encode within their features the beam spatial distribution. The masks used are of a predefined size and can be designed for different resolutions. Our approach eliminates the need of using an array of pixels for detection while still maintaining the high sensitivity and dynamic range of one detector.
•A single pixel camera for THz domain with mechanical encoding mask is proposed.•2.5THz methanol laser beam was analyzed for three different profile patterns.•Information about beam power, waist dimensions and beam shape was revealed.
Herein, we report that nosocomial infection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) may be mitigated by using surgical masks and closed looped ventilation for both ...non-critical and critical patients. These preventive measures resulted in no viral contamination of surfaces in negative pressure environments.
A compact spot size converter (SSC) is the key to the future of optical interconnection. Hence, we proposed a tapered SSC using mask-transfer self-written (MTSW) technology with UV-curable resin. ...MTSW technology guarantees an easy and fast fabrication concept that makes it a promising technology for SSC devices. A prototype SSC adopting this technology was successfully fabricated. It was also confirmed that a tapered shape could be prepared from diffraction effect. A numerical calculation performed using the beam propagation method simulation shows that radiation loss decreases as SSC length increases. Comparison between the simulation and actual fabrication results shows acceptable value. Thus, this approach is reliable and has potential in the future of optical interconnection.
We performed a stress assessment of noninvasive positive pressure ventilation (NPPV) using the salivary biomarkers chromogranin A.
Twenty healthy volunteers were subjected to NPPV for 30 min. We ...collected saliva samples before and after NPPV and evaluated chromogranin A.
We collected saliva samples from 13 volunteers for enzyme measurement. Of the 13 volunteers, 11 showed elevated chromogranin A levels, which were significantly higher after NPPV than before NPPV (p < 0.01). The chromogranin A increase group displayed significantly increased leak flow and reduced respiratory rate and absolute humidity compared with the chromogranin A reduction group.
The increase of leak volume might be a stress factor in patients receiving NPPV.
Salivary biomarkers are attractive as they are noninvasive and convenient. Noninvasive positive pressure ventilation (NPPV), the delivery of mechanical ventilation to those with respiratory failure, can have complications resulting in stress to the patient. Here, we evaluated stress-related salivary biomarkers during NPPV in healthy individuals. Our results suggest that NPPV might increase stress levels and that humidity and leak volume affected stress.
Depth estimation plays an important role in vision-based laparoscope surgical navigation systems. Most learning-based depth estimation methods require ground truth depth or disparity images for ...training; however, these data are difficult to obtain in laparoscopy. The authors present an unsupervised learning depth estimation approach by fusing traditional stereo knowledge. The traditional stereo method is used to generate proxy disparity labels, in which unreliable depth measurements are removed via a confidence measure to improve stereo accuracy. The disparity images are generated by training a dual encoder–decoder convolutional neural network from rectified stereo images coupled with proxy labels generated by the traditional stereo method. A principled mask is computed to exclude the pixels, which are not seen in one of views due to parallax effects from the calculation of loss function. Moreover, the neighbourhood smoothness term is employed to constrain neighbouring pixels with similar appearances to generate a smooth depth surface. This approach can make the depth of the projected point cloud closer to the real surgical site and preserve realistic details. The authors demonstrate the performance of the method by training and evaluation with a partial nephrectomy da Vinci surgery dataset and heart phantom data from the Hamlyn Centre.
Target object detection and identification are among the primary uses for a remote sensing system. This is crucial in several fields, including environmental and urban monitoring, hazard and disaster ...management, and defense and military. In recent years, these analyses have used the tremendous amount of data acquired by sensors mounted on satellite, airborne, and unmanned aerial vehicle (UAV) platforms. This book promotes papers exploiting different remote sensing data for target object detection and identification, such as synthetic aperture radar (SAR) imaging and multispectral and hyperspectral imaging. Several cutting-edge contributions, which provide examples of how to select of a technology or another depending on the specific application, will be detailed.
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