Metallic microparticles can acquire remarkable nanoscale morphologies after experiencing high velocity collisions, but materials science regarding the extreme events has been limited due to a lack of controlled experiments. In this work, collision dynamics and nonlinear material characteristics of aluminum microparticles are investigated through precise single particle collisions with two distinctive substrates, sapphire and aluminum, across a broad range of collision velocities, from 50 to 1,100 m/s. An empirical constitutive model is calibrated based on the experimental results, and is used to investigate the mechanics of particle deformation history. Real-time and post-impact characterizations, as well as model based simulations, show that significant material flow occurs during the impact, especially with the sapphire substrate. A material instability stemming from plasticity-induced heating is identified. The presented methodology, based on the use of controlled single particle impact data and constitutive models, provides an innovative approach for the prediction of extreme material behavior.

A feeding experiment was conducted to determine the effects of α‐lipoic acid (LA) on the growth and antioxidative responses of juvenile abalone Haliotis discus hannai Ino. Six purified diets supplemented with 0, 200, 400, 800, 1600 and 3200 mg kg−1 of LA, respectively, were fed to abalone for 16 weeks in a flow‐through water system. The results showed that the weight gain ratio (WGR) increased with the dietary LA levels, and reached the highest value in the group with 800 mg kg−1 dietary LA supplement. Glutathione peroxidase activity in the 800 mg kg−1 dietary LA group was significantly higher than that in the dietary LA‐deficient (0 mg kg−1) group. Superoxide dismutase activities in the 200, 400 and 800 mg kg−1 groups were significantly increased. Supplements of 200, 400 and 800 mg kg−1 dietary LA elevated the total antioxidative capacity significantly. The glutathione level in the hepatopancreas increased significantly with the dietary LA supplements in a dose‐dependent manner (except for the 200 mg kg−1 group). Catalase and malondialdehyde in the hepatopancreas were not significantly affected by dietary LA. In conclusion, dietary LA promoted the growth and stimulated the antioxidative defence capacity of abalone. Based on the data of WGR, the optimal dietary LA supplement for juvenile abalone was found to be 709 mg kg−1 using piece‐wise linear analysis.

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The objective of the present study was to evaluate the safety and efficacy of percutaneous transforaminal endoscopic discectomy (PTED) and open fenestration discectomy (OFD) in the treatment of lumbar disc herniation (LDH). Methods: Patients in our hospital with LDH who received PTED (n = 71) and OFD (n = 39) from 2013 to 2014 were retrospectively studied. Patient information, including age, gender, visual analogue scale (VAS) score for low back pain and leg pain, body weight, height, Oswestry disability index (ODI), Japanese Orthopedic Association (JOA), and recurrence, was collected. The patients in the two groups were followed up for an average of 63 months after surgery. Results: A total of 136 patients completed the operation and 110 patients were followed up completely. There was no significant difference in baseline data between the two groups (P > 0.05). The postoperative low back pain, leg pain, ODI, and JOA of the two groups were better than those preoperatively (P < 0.05). One week after surgery, the recovery of PTED patients was better than that of OFD. The ODI score of the PTED group was lower than that of the OFD group (10 [8, 12] vs 14 [11, 16]; P < 0.05), the waist VAS score of the PTED group was lower than that of the OFD group (2 [2, 3] vs 3 [2, 4]; P < 0.05), the leg VAS score of the PTED group was lower than that of the OFD group (1 [0,1] vs 1 [1, 2]; P < 0.05), while the JOA score of the PTED group was higher than that of OFD group [19(16, 20) vs 12(10, 17); P < 0.05]. There were no significant differences in ODI, JOA, waist and leg VAS scores between the two groups at 1 month after surgery and at subsequent follow-up (P > 0.05). At the end of the follow up, 89.7% (35/39) of patients in the OFD group had excellent improvement in the JOA score, and 88.7% (63/71) of patients in the PTED group had an excellent improvement. There was no significant difference between the two (P > 0.05). There was also no significant difference in the recurrence rate between the two groups [(5/71) vs (3/39); P > 0.05]. [Correction added on 05 March 2021, after first online publication: "3/29" was amended to "3/39" in the preceding sentence.] Conclusion: Both PTED and OFD can achieve good mid-term efficacy in the treatment of LDH but PTED has certain advantages, including the small incision, a shorter hospital stay, and quicker, earlier recovery. However, prospective randomized controlled studies with a larger sample size are needed.