Planar-type silicon thermoelectric generator with phononic nanostructures for 100 {\mu}W energy harvesting

Energy harvesting is essential for the internet-of-things networks where a tremendous number of sensors require power. Thermoelectric generators (TEGs), especially those based on silicon (Si), are a promising source of clean and sustainable energy for these sensors. However, the reported performance of planar-type Si TEGs never exceeded power factors of 0.1 ${\mu} Wcm^{-2} K^{-2}$ due to the poor thermoelectric performance of Si and the suboptimal design of the devices. Here, we report a planar-type Si TEG with a power factor of 1.3 ${\mu} Wcm^{-2} K^{-2}$ around room temperature. The increase in thermoelectric performance of Si by nanostructuring based on the phonon-glass electron-crystal concept and optimized three-dimensional heat-guiding structures resulted in a significant power factor. In-field testing demonstrated that our Si TEG functions as a 100-${\mu}W$-class harvester. This result is an essential step toward energy harvesting with a low-environmental load and cost-effective material with high throughput, a necessary condition for energy-autonomous sensor nodes for the trillion sensors universe

Space Demonstration of Two-Layer Pop-Up Origami Deployable Membrane Reflectarray Antenna by 3U CubeSat OrigamiSat-2

3U CubeSat OrigamiSat-2 demonstrates a 50-cm × 50-cm two-layer pop-up Origami deployable membrane reflectarray antenna in space. The membrane has small stowage volume and high gain even though it has low flatness because of a large enough antenna area to cover its un-flatness. C-band transmitter is equipped in the CubeSat and offers 20-Mbps amateur satellite communication. In 3U size, a 1-m length deployable gravity gradient mast and magnetic torquer are equipped to stabilize and control its attitude. A camera is attached to the satellite to measure the shape of the membrane antenna. OrigamiSat-2 was selected as the Innovative Satellite Technology Demonstration-4 by Japan Aerospace Exploration Agency (JAXA) and is going to be launched in 2024 by Epsilon Launch Vehicle

Efficacy of Indocyanine Green Angiography on Microsurgical Subinguinal Varicocelectomy

Objectives: Microsurgical subinguinal varicocelectomy is one of the best treatment modalities for varicoceles related to male infertility and scrotal pain. However, the difficulty in identifying testicular arteries, which should be spared, is a limitation of this technique. To visualize and identify the testicular arteries in spermatic cord during the operation, we examined the efficacy of intraoperative indocyanine green angiography (ICGA), which is regularly used in microsurgical neurosurgery. Methods: After the exposure of the spermatic cord blood vessels, ICG was injected intravenously under a surgical microscope for observing infrared fluorescence in patients to identify and isolate the testicular artery. Results: The testicular artery was clearly identified by ICGA and was able to separate under ICGA view. Thereafter, the varicose veins were repeatedly ligated, while preserving a few lymphatic vessels and the spermatic duct. The preserved arteries were confirmed by repeated ICGA at the end of microsurgical operation. The number of arteries identified by ICGA was greater than the number detected by preoperative computed tomography angiogram. Conclusions: Microsurgical subinguinal varicocelectomy using intraoperative ICGA facilitated safe and quick surgery by enabling the visualization of the spermatic cord blood vessels. This is the first report to indicate the usefulness of vessel visualization by ICGA during microsurgical subinguinal varicocelectomy

Improved Arterial Preservation Achieved by Combined Use of Indocyanine Green Angiography and Doppler Detector During Microsurgical Subinguinal Varicocelectomy

Objectives: The microsurgical approach is considered the most reliable procedure in varicocelectomy. However, as there are difficulties in identifying the spermatic artery at the peripheral level, we had introduced intraoperative indocyanine green angiography (ICGA) for identification of arteries. In this study, we further investigated the usefulness of intraoperative ICGA in combination with an ordinary Doppler detector in microsurgical subinguinal varicocelectomy. Methods: A total of 140 men who underwent microsurgical subinguinal varicocelectomy at Gunma University Hospital were included. An operating microscope equipped with a near-infrared charge-coupled device was used for intraoperative ICGA. After exposing the vessels, arteries were identified using endoscopic vision only or with assistance of Doppler detector or ICGA, or of both. The number of preserved arteries was compared among the groups. Results: ICGA clearly visualized the internal spermatic arteries in all cases, allowing the surgeon to perform real-time identification and isolation of the spermatic artery intraoperatively. The use of ICGA or Doppler detector significantly increased the number of preserved arteries compared to the microscope-only operation from 1.11 to 1.75 (p < 0.05) and 1.57 (p < 0.05), respectively. The additional use of ICGA with Doppler detector further increased the number of preserved arteries to 2.41 (p < 0.05). Conclusions: Intraoperative ICGA facilitated safe and quick microsurgical subinguinal varicocelectomy by enabling visualization of thin spermatic cord blood vessels. Improved preservation of thin arteries, which is essential for patients with infertility, can be achieved with the combined use of ICGA and ordinary Doppler detector