Neuromorphic System Using Memcapacitors and Autonomous Local Learning.

Artificial intelligence is used for various applications and is promising as an indispensable infrastructure in future societies. Neural networks are representative technologies that imitate human brains and exhibit various advantages. However, the size is bulky, the power is huge, and some advantages are not demonstrated because they are executed on Neumann-type computers. Neuromorphic systems are biomimetic systems from the hardware level to implement neuron and synapse elements, and the size is compact, the power is low, and the operation is robust. However, because the conventional ones are not composed of fully optimized hardware, the power is not yet minimal, and extra control circuits must be used. In this article, we developed a neuromorphic system using memcapacitors and autonomous local learning. By using memcapacitors, the power can be minimal, and by using autonomous local learning, the control circuits to handle the synapse elements can be deleted. First, the memcapacitors are completed in a cross-bar array, where the ferroelectric layers are sandwiched between the horizontal and perpendicular electrodes. The polarization and capacitance exhibit hysteresis due to the dielectric polarization. Next, autonomous local learning is introduced as follows. During the training phase, associative patterns to be memorized are directly sent, relatively high voltages are applied, and dielectric polarizations are induced. During the operation phase, relatively low voltages are applied, and input signals are weighted with the capacitances of the memcapacitors, summed, and transferred as the output signals. Finally, the experimental system is set up, and the experimental results are acquired. The memorized patterns during the training phase, distorted patterns as the input signals during the operation phase, and retrieved patterns as the output signals in the operation phase are shown. Researchers found that the retrieved patterns are completely the same as the memorized patterns. This means that the neuromorphic system works as an associative memory.

Endoscopic ultrasound-guided antegrade procedures for managing bile duct stones in patients with surgically altered anatomy: Comparison with double-balloon enteroscopy-assisted endoscopic retrograde cholangiography (with video).

BACKGROUND AND STUDY AIM: Management of bile duct stones (BDSs) in patients with surgically altered anatomies (SAAs) remains challenging. An endoscopic ultrasound-guided antegrade (EUS-AG) procedure and double-balloon enteroscopy-assisted endoscopic retrograde cholangiography (DB-ERC) have been used to remove BDSs from patients with SAAs. However, few comparative data have been reported. Therefore, we compared the efficacy and safety of the techniques. METHODS: This was a single-center retrospective study. Patients with SAA who underwent the EUS-AG procedure or DB-ERC to remove intra- or extra-BDSs between November 2010 and March 2020 were included. The primary outcome was the technical success rate, defined as stent insertion or stone removal during the initial session. The secondary outcomes were the procedure time, incidence of adverse events (AEs), and complete stone removal rate. RESULTS: Of the 54 patients enrolled, 23 underwent the EUS-AG procedure and 31 DB-ERC. The technical success rates of EUS-AG and DB-ERC were 87.0% and 64.5%, respectively (P = 0.11). The procedure time was significantly shorter in the EUS-AG group than in the DB-ERC group (51.9 ± 15.4 vs 72.6 ± 32.2 min; P = 0.01), and the early AE rates were 26.1% and 12.9%, respectively (P = 0.71). The complete stone removal rates in patients who underwent previous stone removal were 94.1% in the EUS-AG group and 85.7% in the DB-ERC group (P = 0.61). CONCLUSION: The EUS-AG afforded technical success and complete stone removal rates comparable with those of DB-ERC, but the former procedure was shorter. The AE rate was acceptable.

Assessing the extent of breast cancer using multidetector row helical computed tomography.

OBJECTIVE: The aim of the study was to evaluate the usefulness of multidetector row helical computed tomography (MD-CT) in assessing the local extent of breast cancer. METHODS: Seventy-five breast cancer patients were examined using MD-CT with scanning performed in the supine position at 1-mm collimation. The extent of the breast tumors determined using CT was compared with that based on histopathologic mapping with continuous 5-mm slices. RESULTS: The CT evaluation of the maximum diameter of the extent of breast cancer was much better correlated with the histopathologic diagnosis (correlation coefficient=0.90) than the pre-CT diagnosis (correlation coefficient=0.46). Computed tomography correctly detected mammographically and clinically occult cancer other than the index lesion in 14 of 15 patients. The sensitivity, specificity, and accuracy in the diagnosis of the additional lesions were 93.3%, 98.3%, and 97.3%, respectively. Because the images were obtained in the supine position, they were useful for surgical planning. CONCLUSION: The extent of breast cancer can be determined accurately using MD-CT.

MDCT compared with digital subtraction angiography for assessment of lower extremity arterial occlusive disease: importance of reviewing cross-sectional images.

OBJECTIVE: The aim of our study was to evaluate the efficacy of MDCT angiography in the assessment of lower limb peripheral arterial occlusive disease. MATERIALS AND METHODS: Twenty-four patients (representing 27 cases) with symptomatic lower extremity peripheral arterial occlusive disease underwent both MDCT angiography and digital subtraction angiography of the aortoiliac and lower extremity arteries. For data analysis, the arterial system was divided into 10 segments. Each segment was classified as normal, mildly stenotic, moderately stenotic, severely stenotic, or occluded. In evaluating MDCT angiographic findings, cross-sectional images were mainly observed by scrolling. The diagnostic accuracy of MDCT angiography was determined, using digital subtraction angiography as the standard reference. The extent of calcification in each segment was also assessed on MDCT angiography and was classified as absent, mildly calcified, or severely calcified. RESULTS: Of the 480 segments studied, 470 were assessable on both digital subtraction angiography and MDCT angiography. On digital subtraction angiography, 142 stenoocclusive segments (20 mildly stenotic, 14 moderately stenotic, 25 severely stenotic, and 83 occluded) were detected. With regard to the detection of segments that had more than mild stenosis, the sensitivity, specificity, and accuracy of MDCT angiography were 99.2%, 99.1%, and 99.1%, respectively. In the 421 noncalcified and mildly calcified segments, the sensitivity, specificity, and accuracy of MDCT angiography for the detection of more-than-mild stenosis were 100%, 100%, and 100%, respectively. CONCLUSION: MDCT angiography is a reliable method for evaluating the aortoiliac and lower extremity arteries.

Demonstration of the artery of Adamkiewicz at multi- detector row helical CT.

PURPOSE: To assess the ability of multi-detector row helical computed tomography (CT) to depict the artery of Adamkiewicz. MATERIALS AND METHODS: Seventy patients with vascular diseases underwent multi-detector row helical CT of the entire aorta and iliac arteries. The artery of Adamkiewicz was examined on multiplanar and curved planar reformation images and on cine-mode displays. The visualization of the artery of Adamkiewicz, as well as its branching level and side of origin, was investigated. RESULTS: In 63 (90%) of the 70 patients, at least a single artery of Adamkiewicz was clearly visualized from the intervertebral foramen to the hairpin-shaped union with the anterior spinal artery. Two arteries of Adamkiewicz were identified in 15 (24%) of 63 patients. Fifty-five arteries of Adamkiewicz (71%) originated from the left side. Seventy-two (92%) originated between T8 and L1. Neither the intercostal vein nor the posterior spinal vein were visualized in 57 of 63 patients. Continuity of the entire length, starting from the stem of the intercostal or lumbar artery and proceeding to the artery of Adamkiewicz and finally to the anterior spinal artery, was traceable on cine-mode displays or on curved planar reformation images in 20 of 63 patients. CONCLUSION: Multi-detector row helical CT depicts the artery of Adamkiewicz in a high percentage of patients.