Thyroid nodule is a common and frequently occurring disease in the neck in recent years, and ultrasound has become the preferred imaging diagnosis method for thyroid nodule due to its advantages of noninvasive, nonradiation, real‐time, and repeatable. The thyroid imaging, reporting and data system (TI‐RADS) classification standard scores suspicious nodules that are difficult to determine benign and malignant as grade 4, and further pathological puncture is recommended clinically, which may lead to a large number of unnecessary biopsies and operations. Including conventional ultrasound, ACR TI‐RADS, shear wave elastography, super microvascular imaging, contrast enhanced ultrasound, “firefly,” artificial intelligence, and multimodal ultrasound imaging used in combination. In order to identify the most clinically significant malignant tumors when reducing invasive operations. This article reviews the application and research progress of multimodal ultrasound imaging in the diagnosis of TI‐RADS 4 thyroid nodules.

Background Bone marrow mononuclear cells (BMMNCs) can counteract oxidative stress and inhibit the inflammatory response in focal ischemic stroke models. However, the effect of BMMNC transplantation on carotid atherosclerosis needs to be determined. Methods The carotid atherosclerotic plaque model was established in New Zealand White rabbits by balloon injury and 8 weeks of high-fat diet. Rabbits were randomized to receive an intravenous injection of autologous BrdU-labeled BMMNCs or an equal volume of phosphate-buffered saline. Plaques were evaluated for expression of proinflammatory and anti-inflammatory cytokines, antioxidant proteins, and markers of cell death. Results BMMNCs migrated into atherosclerotic plaque on the first day after cell transplantation. BMMNC-treated rabbits had smaller plaques and more collagen deposition than did the vehicle-treated controls on day 28 (p<0.05). BMMNC treatment significantly increased endothelial nitric oxide synthase and the antioxidant enzymes glutathione peroxidase and superoxide dismutase in plaques compared to vehicle treatment on day 7. BMMNC-treated rabbits also had lower levels of cleaved caspase-3 expression; lower levels of proinflammatory cytokines interleukin-1β, tumor necrosis factor-α, and matrix metalloproteinase 9; and higher levels of insulin-like growth factor-1 and its receptor (p<0.05). Conclusions Autologous BMMNC transplantation can suppress the process of atherosclerotic plaque formation and is associated with enhanced antioxidative effect, reduced levels of inflammatory cytokines and cleaved caspase-3, and increased expression of insulin-like growth factor-1 and its receptor. BMMNC transplantation represents a novel approach for the treatment of carotid atherosclerosis.

Objective To determine if the artificial intelligence‐based Thyroid Imaging, Reporting and Data System (AI TIRADS) would perform better than the American College of Radiology (ACR) TIRADS in monitoring malignant thyroid nodules not recommended for biopsy using follow‐up thresholds. Methods A total of 3499 thyroid nodules with surgical histopathology and ultrasound features were retrospectively reviewed and categorized using ACR TIRADS and AI TIRADS. The recommendations for biopsy and follow‐up divided nodules into three groups 1) fine needle aspiration (FNA), 2) follow‐up ultrasound, and 3) no further evaluation. Results Of the total 1608 malignant nodules in this study, 974 malignant nodules would not be biopsied in ACR TIRADS compared with 967 in AI TIRADS. While 60.0% (584/974) of these non‐biopsied malignancies could be followed‐up by ultrasound in ACR TIRADS and 62.8% (607/967) in AI TIRADS. For the malignancies of no further evaluation, 97.4% (380/390) were sized <10 mm in ACR TIRADS and 93.3% (336/360) in AI TIRADS. Compared with ACR TIRADS, AI TIRADS had lower unnecessary FNA rate and missing cancer rate (41.0% vs 47.8% and 22.8% vs 27.5%, P < .05, respectively) while having higher specificity and AUC as well as lower sensitivity (65.0% vs 57.9%, 0.895 vs 0.881, and 96.1% vs 97.8%, all P < .05). Conclusions Using the follow‐up thresholds, more than half of the malignancies not being biopsied were monitored by ultrasound in both ACR TIRADS and AI TIRADS, and AI TIRADS had lower missing cancer rate. More than 90% of malignancies recommended for no further evaluation were <10 mm in diameter.

Traditional research on static wake-vortex reduction usually considers only the influence of external environmental factors, while ignoring the dynamic change in an aircraft’s flight state. In order to solve this problem, this paper proposes a method to reduce separation using dynamic wake information based on changes in flight velocity. Firstly, relying on the wake-vortex generation and dissipation model, the initial circulations and dissipation parameters of the wake vortex at different aircraft velocities are calculated. Then, the complete evolution process of the wake vortex generated by different types of aircraft at different velocities is analyzed, and the evolution law of a wake vortex with changing velocity is obtained. Afterwards, according to the actual aerodynamic shape of CRJ-900, the aerodynamic model for CRJ-900 when it encounters a wake vortex is established. The situation of an CRJ-900 encountering a wake vortex under TBS is analyzed, which proves that TBS is safe and has a certain reduction potential. Then, taking the rolling moment coefficient as the safety index, the minimum safe separations at different velocities are calculated. Finally, a simulation for the separation reduction based on a dynamic wake vortex is carried out. Compared with the static wake-based separation, the dynamic wake-based separation technology can greatly reduce the aircraft separation requirements while ensuring the operation safety. The final simulation results show that the dynamic separation reduction in CRJ-900 following a medium and heavy aircraft can reach 44.3% and 51.6%, respectively.

Herein a practical and efficient potassium tert-butoxide (KOtBu)-facilitated amine acyl exchange reaction of N,N-dimethylformamide (DMF) with carboxylic acids is described. In the presence of catalytic amount of KOtBu, a variety of aliphatic and aromatic carboxylic acids are transformed to N,N-dimethylamides using DMF as the dimethylamine reagent with the assistance of trimethylacetic anhydride. The applicability of this protocol is demonstrated by late-stage dimethylamidation of complex drug molecules. A plausible reaction mechanism involving KOtBu-facilitated amine in situ generation from formamide decomposition and anhydride-mediated condensation is proposed on the base of mechanism investigations