Fusion of memristor and digital compute-in-memory processing for energy-efficient edge computing.

Artificial intelligence (AI) edge devices prefer employing high-capacity nonvolatile compute-in-memory (CIM) to achieve high energy efficiency and rapid wakeup-to-response with sufficient accuracy. Most previous works are based on either memristor-based CIMs, which suffer from accuracy loss and do not support training as a result of limited endurance, or digital static random-access memory (SRAM)-based CIMs, which suffer from large area requirements and volatile storage. We report an AI edge processor that uses a memristor-SRAM CIM-fusion scheme to simultaneously exploit the high accuracy of the digital SRAM CIM and the high energy-efficiency and storage density of the resistive random-access memory memristor CIM. This also enables adaptive local training to accommodate personalized characterization and user environment. The fusion processor achieved high CIM capacity, short wakeup-to-response latency (392 microseconds), high peak energy efficiency (77.64 teraoperations per second per watt), and robust accuracy (<0.5% accuracy loss). This work demonstrates that memristor technology has moved beyond in-lab development stages and now has manufacturability for AI edge processors.

Short-term and Long-term Risk of Stroke in Patients With Perioperative Atrial Fibrillation After Cardiac Surgery: Systematic Review and Meta-analysis.

BACKGROUND: Perioperative atrial fibrillation (POAF) after cardiac surgery has been associated with an increased risk of stroke in some studies. However, the exact magnitude of this association during short-term and long-term follow-up remains unclear. METHODS: We searched PubMed, Embase, and Cochrane Central Register of Controlled Trials (CENTRAL) for the time period from database inception to October 2020. We included observational studies with ≥ 100 patients that reported data on short-term or long-term stroke risk in patients with and without POAF after cardiac surgery. Data were pooled using random-effects models. We reported summary risk ratios (RRs) for studies reporting multivariable adjusted results and calculated absolute risk differences (ARDs) with 95% confidence intervals (CIs). RESULTS: A total of 55 studies with 540,209 patients were included. POAF was associated with both an increased relative risk (RR 1.69; 95% CI, 1.41-2.03; I2 = 82%; 9 studies) and absolute risk of short-term stroke (4.5% vs 2.5%; ARD 2.0%; 95% CI, 1.28-2.89). POAF was associated with an increased relative risk (RR 1.20; 95% CI, 1.12-1.29; I2 = 16%; 10 studies) and absolute risk of long-term stroke (1.06 vs 0.88 per 100 patient-years; ARD 0.18 per 100 patient-years; 95% CI, 0.07-0.26). Sensitivity analyses of high-quality studies and studies reporting either ischemic or embolic strokes yielded similar findings. CONCLUSIONS: POAF after cardiac surgery was associated with an increased risk of both short-term and long-term stroke. However, the long-term stroke ARD was small, and whether these patients will benefit from long-term oral anticoagulation therapy is unclear.

CONTEXTE: La fibrillation auriculaire périopératoire (FAPO) après une chirurgie cardiaque a été associée à un risque accru d'accident vasculaire cérébral (AVC) dans certaines études. Cependant, l'ampleur exacte de cette association durant le suivi à court et à long terme reste incertaine. MÉTHODOLOGIE: Nous avons effectué des recherches dans les bases de données PubMed, Embase et CENTRAL (Cochrane Central Register of Controlled Trials) pour la période allant de la création de ces bases à octobre 2020. Nous avons inclus des études d'observation comptant ≥ 100 patients et rapportant des données sur le risque d'AVC à court ou à long terme chez les patients ayant présenté ou non une FAPO après une chirurgie cardiaque. Les données ont été regroupées à l'aide de modèles à effets aléatoires. Nous avons consigné les rapports de risque (RR) sommaires pour les études rapportant des résultats corrigés multivariables et calculé les différences de risque absolu (DRA) avec des intervalles de confiance (IC) à 95 %. RÉSULTATS: Au total, 55 études portant sur 540 209 patients ont été incluses. La FAPO était associée à une augmentation tant du risque relatif (RR : 1,69; IC à 95 % : 1,41 à 2,03; I2 = 82 %; 9 études) que du risque absolu d'AVC à court terme (4,5 % vs 2,5 %; DRA : 2,0 %; IC à 95 % : 1,28 à 2,89). La FAPO était également associée à une augmentation du risque relatif (RR : 1,20; IC à 95 % : 1,12 à 1,29; I2 = 16 %; 10 études) et du risque absolu d'AVC à long terme (1,06 vs 0,88 par 100 années-patients; DRA : 0,18 par 100 années-patients; IC à 95 % : 0,07 à 0,26). Les analyses de sensibilité des études de haute qualité et des études rapportant des AVC ischémiques ou emboliques ont donné des résultats similaires. CONCLUSIONS: La FAPO après une chirurgie cardiaque a été associée à un risque accru d'AVC à court et à long terme. Cependant, comme la différence de risque absolu d'AVC à long terme était faible, la possibilité qu'une anticoagulothérapie orale à long terme soit bénéfique pour ces patients est incertaine.

Adoption of the Wet Surface Treatment Technique for the Improvement of Device Performance of Enhancement-Mode AlGaN/GaN MOSHEMTs for Millimeter-Wave Applications.

In this work, a low-power plasma oxidation surface treatment followed by Al2O3 gate dielectric deposition technique is adopted to improve device performance of the enhancement-mode (E-mode) AlGaN/GaN metal-oxide-semiconductor high-electron-mobility transistors (MOSHEMTs) intended for applications at millimeter-wave frequencies. The fabricated device exhibited a threshold voltage (Vth) of 0.13 V and a maximum transconductance (gm) of 484 (mS/mm). At 38 GHz, an output power density of 3.22 W/mm with a power-added efficiency (PAE) of 34.83% were achieved. Such superior performance was mainly attributed to the high-quality Al2O3 layer with a smooth surface which also suppressed the current collapse phenomenon.

Combining Augmented Radiotherapy and Immunotherapy through a Nano-Gold and Bacterial Outer-Membrane Vesicle Complex for the Treatment of Glioblastoma.

Glioblastoma, formerly known as glioblastoma multiforme (GBM), is refractory to existing adjuvant chemotherapy and radiotherapy. We successfully synthesized a complex, Au-OMV, with two specific nanoparticles: gold nanoparticles (AuNPs) and outer-membrane vesicles (OMVs) from E. coli. Au-OMV, when combined with radiotherapy, produced radiosensitizing and immuno-modulatory effects that successfully suppressed tumor growth in both subcutaneous G261 tumor-bearing and in situ (brain) tumor-bearing C57BL/6 mice. Longer survival was also noted with in situ tumor-bearing mice treated with Au-OMV and radiotherapy. The mechanisms for the successful treatment were evaluated. Intracellular reactive oxygen species (ROS) greatly increased in response to Au-OMV in combination with radiotherapy in G261 glioma cells. Furthermore, with a co-culture of G261 glioma cells and RAW 264.7 macrophages, we found that GL261 cell viability was related to chemotaxis of macrophages and TNF-α production.