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Open reduction internal fixation technique has been generally accepted for treatment of complex humeral fractures. Traditional proximal humeral locking plate design (PHILOS) have been reported in clinical or biomechanical researches, while presently the spiral plate design has been introduced improved biomechanical behavior over conventional designs. In order to objectively realize the multi-directional biomechanical performances and minimally invasive surgery for humeral plate designs, a current conceptual finite element analysis has been conducted with identical cross-sectional features for humeral plates. The conceptual lateral, and spiral humeral plate models were constructed for virtual reduction and fixation to the multiple fractures of the humerus. Mechanical load cases including axial compression, counterclockwise torsion and anterior bending have been applied for confirming the multi-directional structural stability and implant safety in biomechanical perspective. Results revealed that the lateral humeral plate model showed lower equivalent (von-Mises) stress under counterclockwise torsion, while the spiral humeral plate model performed greater rigidity and lower equivalent (von-Mises) stress under other loading cases. Four models represented similar structural stiffness under bending load. Under the different mechanical load cases, the spiral humeral plate model revealed comparable results with acceptable multi-directional biomechanical behavior. The concept of spiral humeral plate design is worth considering in practical application in clinics. Implant safety and stability should be further investigated by evidences in future mechanical tests and clinical observations.

Elongated protein 2 (ELP2) affects inflammatory responses through the JAK-STAT3 cascade and downstream pathways which regulates ontogenesis. Our recent experiment suggests that TNF-a induced inflammation during ontogenesis is inextricably linked to pyroptosis and is critical for inhibiting osteogenic differentiation. However, we do not know the effect of ELP2 on pyroptosis under inflammatory microenvironment. Thus, this study aims to investigate the role of ELP2 in molecular mechanism for MC3T3-E1 cell pyroptosis. Firstly, using scanning electron microscope, we observed MC3T3-E1 cells underwent obvious cell membrane rupture and inflammation after 48h of TNF-α treatment under ontogenesis induction. Then, we targeted ELP2 associated with the NLRP3 inflammasome identified by bioinformatics analysis. Besides, the effect of ELP2 on the inflammasome was determined by the detection of STAT3/NLRP3/ASC protein in ELP2 knockdown and overexpression cells. The interaction between ELP2 and NLRP3 was confirm by co-immunoprecipitation. Pyroptosis downstream was demonstrated by activation of Caspase-1 and Caspase-3, cleavage of downstream gas protein D (GSDMD) and gas protein E (GSDME/DFNA5). Clarifying the effect of ELP2 on the degree of apoptosis by Fluorescent Staining and Flow Quantitative Analysis of Cell Death Staining. Finally, the effects of ELP2 on ontogenesis was evaluated by detecting the osteogenic associated protein OPN/OCN/RUNX2/ALP expression using western blot and qPCR, also we conducted the ALP staining after the cell was stimulated with TNF-α. From the data in this study, we get ELP2-NLRP3-GSDMD/GSDME mediated pyroptosis induced by TNF-α during osteogenic differentiation. Regulation of ELP2 may be a potential target for the treatment of bone infections.

Wen-Jiao Wu,1,* Chang-Liang Xia,1,* Shuan-Ji Ou,1 Yang Yang,1 Xiao-Zhong Zhou,1 Yun-Fei Ma,2 Yi-Long Hou,2 Fa-Zheng Wang,3 Qing-Po Yang,3 Yong Qi,1,4 Chang-Peng Xu1,4 1Department of Orthopaedics, Guangdong Second Provincial General Hospital, Guangzhou, Guangdong, People’s Republic of China; 2Department of Orthopaedics and Traumatology, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong, People’s Republic of China; 3Department of Orthopaedics, First People’s Hospital of Kashgar Prefecture, Kashgar, Xinjiang, People’s Republic of China; 4The Second School of Clinical Medicine, Southern Medical University, Guangzhou, Guangdong, People’s Republic of China*These authors contributed equally to this workCorrespondence: Yong Qi; Chang-Peng Xu, Tel +86-20-8916-8085, Email gd2hqy@163.com; gd2hxcp@163.comIntroduction: Osteomyelitis is characterized by intensive inflammatory bone disease and remains a clinical challenge in orthopedic surgery, despite the advances made in medical and surgical therapies. Staphylococcus aureusis a major causative agent of osteomyelitis, causing the progressive inflammatory destruction of bone. Prophylaxis of osteomyelitis during orthopedic surgery is necessary. NFκB essential modulator–binding domain (NBD) peptides are cell-permeable peptide inhibitors of the IκB-kinase complex. The prophylactic effect of NBD peptides in relieving inflammation and inhibiting bone defects in osteomyelitis is still under investigation. Our purpose was to determine the preventive effect of NBD peptides in S. aureus infection–induced bone defects in osteomyelitis.Methods: An S. aureus osteomyelitis rabbit model was used in this study. The rabbits were divided into four groups: NBD, cefazolin, control, and PBS. Clinical and laboratory indicators of erythrocyte-sedimentation rate, CRP, and TNFα levels were assessed to monitor systemic reactions. The efficacy of NBD peptides in S. aureus–induced osteomyelitis was evaluated by radiological, histological, and microbiological examinations, immunohistochemistry, immunofluorescence, and micro-CT scans.Results: In general, NBD peptides effectively reduced clinical signs in rabbits when compared with the control group. Radiography indicated that there was more severe osteomyelitis in the bacterium-infection control group. There was no significance between cefazolin- and NBD-group average scores. The histological results of the lesion slices further confirmed different severity among the groups. Additionally, significant pathological differences were found between the cefazolin and NBD groups, and the PBS group showed no obvious pathological changes.Conclusion: Prophylactic administration of NBD peptides to bone-defect areas inhibited bacterial spread and promoted bone regeneration, making NBD peptides a possible treatment option for prophylaxis in bone infections.Keywords: NBD peptide, bone infection, Staphylococcus aureus, osteomyelitis

Conventional model predictive control aims to minimize ripples of the torque, stator flux and current at the end instant of each control period. However, the trajectories of the torque and flux during the entire control period are changed when multiple voltage vectors are applied in different sequences in each period. This indicates that the ripples of the torque and stator flux are influenced by different vector sequences (i.e., the sequence multiple vectors applied in). For that issue, this paper analyzes the RMS values of the stator flux vector ripple when three basic vectors are applied in different five-segment sequences, and proposes a predictive control with optimal vector sequence method. Based on this analysis, the available vector sequences that reduce the stator flux vector ripple are screened out. Moreover, a cost function is constructed to select the optimal vector sequence by evaluating the stator flux ripple during the entire control period and the tracking error of the stator flux vector at the end instant of each control period. Finally, simulation and experimental results verify the effectiveness of the proposed method.

Tumor necrosis factor-α is a common cytokine that increases in inflammatory processes, slows the differentiation of bone formation, and induces osteodystrophy in the long-term inflammatory microenvironment. Our previous study confirmed that the Elongation protein 2 (ELP2) plays a significant role in osteogenesis and osteogenic differentiation, which is considered a drug discovery target in diseases related to bone formation and differentiation. In this study, we applied an in silico virtual screening method to select molecules that bind to the ELP2 protein from a chemical drug molecule library and obtained 95 candidates. Then, we included 11 candidates by observing the docking patterns and the noncovalent bonds. The binding affinity of the ELP2 protein with the candidate compounds was examined by SPR analysis, and 5 out of 11 compounds performed good binding affinity to the mouse ELP2 protein. After in vitro cell differentiation assay, candidates 2# and 5# were shown to reduce differentiation inhibition after tumor necrosis factor-α stimulation, allowing further optimization and development for potential clinical treatment of inflammation-mediated orthopedic diseases.

Tumor necrosis factor-α is a common cytokine that increases in inflammatory processes, slows the differentiation of bone formation, and induces osteodystrophy in the long-term inflammatory microenvironment. Our previous study confirmed that the Elongation protein 2 (ELP2) plays a significant role in osteogenesis and osteogenic differentiation, which is considered a drug discovery target in diseases related to bone formation and differentiation. In this study, we applied an in silico virtual screening method to select molecules that bind to the ELP2 protein from a chemical drug molecule library and obtained 95 candidates. Then, we included 11 candidates by observing the docking patterns and the noncovalent bonds. The binding affinity of the ELP2 protein with the candidate compounds was examined by SPR analysis, and 5 out of 11 compounds performed good binding affinity to the mouse ELP2 protein. After in vitro cell differentiation assay, candidates 2# and 5# were shown to reduce differentiation inhibition after tumor necrosis factor-α stimulation, allowing further optimization and development for potential clinical treatment of inflammation-mediated orthopedic diseases.

In this paper, a direct torque control algorithm with novel duty cycle-based modulation is proposed for permanent magnet synchronous motor drives fed by neutral-point clamped three-level inverters. Compared with the standard DTC, the proposed algorithm can suppress steady-state torque ripples as well as ensure neutral-point potential balance and smooth vector switching. A unified torque/flux evaluation table with multiple voltage vectors and precise control levels is established and used in this method. This table can be used to evaluate the effects of duty-cycle vectors on torque and flux directly, and the elements of the table are independent of the motor parameters. Consequently, a high number of appropriate voltage vectors and their corresponding duty cycles can be selected as candidate vectors to reduce torque ripples by looking up the table. Furthermore, small vectors are incorporated into the table to ensure the neutral-point potential balance with the numerous candidate vectors. The feasibility and effectiveness of the proposed algorithm are verified by both simulations and experiments.

This paper proposes a novel direct power control (DPC) strategy for neutral-point-clamped (NPC) three-level rectifiers, to directly control the active power, the reactive power and the neutral point potential of the rectifiers by referring to three pre-calculated vector influence tables and minimizing an objective function. In the three vector influence tables, the influences of different voltage vectors on the active power, the reactive power and the neutral-point potential are shown explicitly. A conceptual description and control algorithm of the proposed controller are presented in this paper. Then, numerical simulations and experiments are carried out to validate the proposed method. Both the simulation and experimental results show that good performances during both the steady-state and transient operating conditions are achieved. As a result, the proposed strategy has been proven to be effective for NPC three-level rectifiers.

Flux linkage of switch reluctance motor is in nonlinear function of both rotor position and phase current. Establishing this nonlinear mapping is the base to compute the mathematical equations of switch reluctance motor accurately. In this paper, the pi-sigma neural network is employed to develop the nonlinear model of switch reluctance motor. By taking advantage of the benefit of neural network and Takagi-Sugeno type fuzzy logic inference, the pi-sigma neural networks has a simple structure, less training epoch, fast computational speed and a property of robustness. Compared with the training data and generalization test data, the output data of the developed model are in good agreement with those data. The simulated current wave is also in good agreement with the measured current wave. This proves that the model developed in this paper has high accuracy, strong generalization ability, fast computational speed and characteristic of robustness.

A sensorless control method of brushless DC (BLDC) motors is presented in this paper. Differently from the previous ones, this method is based on the zero crossing of line back EMFs, which is proofed corresponding to the commutation points and more reliable at low speeds. For the accuracy and robust of the method, an artificial neural network with a section dealing with the outliers is also employed to estimate the line back EMFs by only using measurements of the stator line voltages and currents. The method provides more wide-speed range, and no neutral voltage, phase shifted or silent phase required. A simulation result of the proposed sensorless method is shown. Also, the performance of the proposed method is verified by real-time experiments using the digital signal processor (DSP) TMS320LF2407A.