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Objective 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). 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., This retrospective study evaluates the safety and efficacy of PTED and OFD in the treatment of lumbar disc herniation.

Summary of background data Cervical sagittal balance is an important evaluation index of cervical physiological function and surgical efficacy. Subaxial kyphosis after atlantoaxial fusion is negatively associated with worse clinical outcomes and higher incidence of lower cervical disk degeneration. Objectives This study aimed to confirm the factors that influence subaxial lordosis loss after posterior atlantoaxial fusion. Methods We performed a retrospective review of all patients following posterior C1–C2 fusion for atlantoaxial dislocation between January 2015 and December 2017. All charts, records, and imaging studies were reviewed for each case, and preoperative, immediate postoperative, and final follow-up plain films were evaluated. Comparing final follow-up and preoperative C2–C7 angle, patients were divided into two groups for further comparison: subaxial lordosis loss group and subaxial lordosis increase group. Results A total of 18 patients were included in the review, with an average radiographic follow-up of 8.4 ± 3.7 months (range 6–17 months). Subaxial lordosis loss was observed in 5 cases (27.8%) at the final follow-up, whereas 13 cases had an increase in subaxial lordosis. The cervical sagittal parameters of preoperative and final follow-up between two groups were compared, the preoperative C2–C7 angle of the subaxial lordosis loss group was bigger than the subaxial lordosis increase group (27.6° ± 10.5° vs 10.5° ± 10.5°, P χ2 = 4.923, P = 0.026). However, Logistic regression analysis showed that the preoperative C2–C7 angle ≥ 20° was not an independent risk factor (OR = 0.147, P = 0.225). Conclusion Our study demonstrates that subaxial lordosis loss may occur after posterior atlantoaxial fusion, and preoperative C2–C7 angle ≥ 20° was a risk factor of postoperative loss of subaxial lordosis.

To study the distribution of bone cement in unilateral puncture percutaneous vertebroplasty (PVP). A total of 64 patients with osteoporotic vertebral compression fractures (OVCF) who underwent unilateral PVP were included in this study. The vertebral body was longitudinally divided into four equal parts. The intermediate layer between each part was representative of the part and there were four layers in total. Each layer was divided into 4 regions a, b, c, and d by the crossed lines at the center of the vertebral body. Region c was the first half of the puncture side and region d was the second half of the puncture side. Region a was the first half of the opposite side, and b was the second half of the opposite side. Bone cement filling areas in the four layers and the four regions of each layer were compared. There were significant differences in visual analogue scale (VAS) scores before and after surgery (P

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 new esterified starch, rosin acid starch (RAS), had been synthesized under mild conditions, using rosin as a starting material directly with Novozym 435 as a catalyst. In order to improve the efficiency of the enzymatic reaction, native cassava starch (NCS) was pretreated by heat-moisture, ultrasonic, gelatinized, microwave and alkali before the enzymatic esterification. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis showed that the morphology and crystallinity of the NCS were changed according to the pretreated methods. Compared with NCS, the surface of ultrasonic and heat-moisture pretreated starch (PS) maintained a smooth and circular morphology structure, and the PS remained highly crystalline. The surface of alkali, microwave and gelatinized PS was changed from smooth to crude, with reducing crystalline, but they maintained some kinds of granule shapes. The activated effect of pretreatment on the degree of substitution (DS) of RAS was as follows: alkali RAS (0.0808) > microwave RAS (0.0174) > gelatinized RAS (0.0153) > ultrasonic RAS (0.0099) > heat-moisture RAS (0.0073) > native RAS (0.0053). The esterified products from PS were confirmed by FT-IR spectroscopy and nuclear magnetic resonance (NMR) analysis.

A 4 × 3 two-factor experiment was designed to study the effects of dietary protein and lipid on growth performances and feed utilization of two species of juvenile catfish, Silurus meridionalis Chen and S. asotus Linnaeus, with the initial weight 9.16 ± 0.01 g and 9.10 ± 0.01 g, respectively. Twelve extruded pellet diets were formulated to contain four levels of protein (46%, 43%, 40% and 37%) and three levels of lipid (13%, 10% and 7%). Each diet was fed to a triplicate group of catfish for 8 weeks in a flow-through water system. The results showed that dietary protein had significant effects on the weight gain rate (WGR) of S. meridionalis Chen, and the feed intake (FI), feed efficiency ratio (FER) and protein efficiency ratio (PER) of both catfish ( P S. meridionalis Chen was found as 1193.10 % in the group with 46% of dietary protein and 7% of dietary lipid. And that for S. asotus Linnaeu was found as 939.98 % with 43% of dietary protein and 7% of dietary lipid. The FI of both catfish decreased with the increasing of dietary protein level. The FER of both catfish were positively related with dietary protein level ( S. meridionalis Chen, r = 0.820, p = 0.000; S. asotus Linnaeus, r = 0.630, p = 0.000), but negatively related with FI ( S. meridionalis Chen, r = − 0.947, p = 0.000; S. asotus Linnaeus, r = − 0.927, p = 0.000). The PER of both catfish were significantly affected by dietary protein ( P S. meridionalis Chen and S. asotus Linnaeu was 43: 10 and 43: 7, respectively. Furthermore, S. meridionalis Chen got relatively higher growth, feed utilization and better body morphological indices than S. asotus Linnaeu under the present experimental conditions.

We develop a pre-treatment planning method for optimum hepatic radiofrequency (RF) ablation. In conventional methods, pre-treatment planning is minimal and for a specific tumor size, it only includes reading pre-specified treatment length and input voltage values from a look-up table that lists experimentally obtained ablation parameters. Such planning, in order to assure certain level of cell death, usually results in more healthy cell damage than desired. Different than the conventional methods, here, we develop a model-based pre-treatment optimal planning framework. As an example, we use 1-D axisymmetric tissue geometry and over this geometry, we solve Pennes' bioheat and Laplace equations to model the RF heating. Using the solutions of these equations, we define constrained nonlinear optimization problems to achieve specific temperature profiles in certain areas of the tissue. Results demonstrate that compared to the conventional methods, our approach significantly improves the healthy tissue preservation.

This article presents a model-based pre-treatment optimal planning framework for hepatic tumour radiofrequency (RF) ablation. Conventional hepatic radiofrequency (RF) ablation methods rely on pre-specified input voltage and treatment length based on the tumour size. Using these experimentally obtained pre-specified treatment parameters in RF ablation is not optimal to achieve the expected level of cell death and usually results in more healthy tissue damage than desired. In this study we present a pre-treatment planning framework that provides tools to control the levels of both the healthy tissue preservation and tumour cell death. Over the geometry of tumour and surrounding tissue, we formulate the RF ablation planning as a constrained optimization problem. With specific constraints over the temperature profile (TP) in pre-determined areas of the target geometry, we consider two different cost functions based on the history of the TP and Arrhenius index (AI) of the target location, respectively. We optimally compute the input voltage variation to minimize the damage to the healthy tissue while ensuring a complete cell death in the tumour and immediate area covering the tumour. As an example, we use a simulation of a 1D symmetric target geometry mimicking the application of single electrode RF probe. Results demonstrate that compared to the conventional methods both cost functions improve the healthy tissue preservation.