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Moving mechanical interfaces need to be lubricated to ensure long life and easy slippage; here, a new type of coating is described—comprising nitrides of either molybdenum or vanadium, together with a copper or nickel catalyst—that generates protective tribofilms from lubricating oils. Low-friction tribofilms created in situ This paper describes a novel approach to lubrication between moving mechanical interfaces that relies on the extraction of carbon tribofilms in situ directly from the base-oil molecules on catalytically active, sliding nanometre-scale crystalline surfaces. The newly developed coatings — comprising molybdenum or vanadium nitrides plus a copper or nickel catalyst — deposited on steel substrates generate protective tribofilms from lubricating oils that virtually eliminate wear and provide lower friction than films produced from formulated lubricants. Moving mechanical interfaces are commonly lubricated and separated by a combination of fluid films and solid ‘tribofilms’, which together ensure easy slippage and long wear life 1 . The efficacy of the fluid film is governed by the viscosity of the base oil in the lubricant; the efficacy of the solid tribofilm, which is produced as a result of sliding contact between moving parts, relies upon the effectiveness of the lubricant’s anti-wear additive (typically zinc dialkyldithiophosphate) 2 . Minimizing friction and wear continues to be a challenge, and recent efforts have focused on enhancing the anti-friction and anti-wear properties of lubricants by incorporating inorganic nanoparticles and ionic liquids 3 , 4 . Here, we describe the in operando formation of carbon-based tribofilms via dissociative extraction from base-oil molecules on catalytically active, sliding nanometre-scale crystalline surfaces, enabling base oils to provide not only the fluid but also the solid tribofilm. We study nanocrystalline catalytic coatings composed of nitrides of either molybdenum or vanadium, containing either copper or nickel catalysts, respectively. Structurally, the resulting tribofilms are similar to diamond-like carbon 5 . Ball-on-disk tests at contact pressures of 1.3 gigapascals reveal that these tribofilms nearly eliminate wear, and provide lower friction than tribofilms formed with zinc dialkyldithiophosphate. Reactive and ab initio molecular-dynamics simulations show that the catalytic action of the coatings facilitates dehydrogenation of linear olefins in the lubricating oil and random scission of their carbon–carbon backbones; the products recombine to nucleate and grow a compact, amorphous lubricating tribofilm.

Purpose To explore the optimal volume fraction percentage (VF%) and influencing factors of bone cement distribution in percutaneous vertebroplasty (PVP) for osteoporotic vertebral compression fractures (OVCF) using digital techniques. Patients and methods From January 2019 to February 2021, 150 patients with 0VCF who underwent PVP surgery in our hospital were analyzed. Based on postoperative X-ray and CT, the spatial distribution score of the intravertebral cement was calculated and the patients were divided into two groups: 0–7 were divided into group A; 8–10 were divided into group B. The general data of the two groups of patients were compared, and Mimics three-dimensional reconstruction images were used to measure the cement dispersion volume (CDV), vertebral body volume (VBV), and VF%. Factors affecting bone cement distribution were included in a multifactorial logistic regression analysis to construct a receiver operating characteristic (ROC) curve, calculate a cut-off value for the extensive distribution of bone cement, and analyze the correlation between bone cement distribution scores and VF%. Results There were 60 patients in group A and 90 patients in group B. Univariate analysis showed that bone mineral density (BMD), cement leakage, CDV, and VF% were significantly lower in group A than in group B ( p  < 0.05). Multivariate logistic regression analysis showed that BMD and VF% were independent influencing factors on bone cement distribution. The area under the curve (AUC) of VF% was 84.7%, and the cut-off value for extensive distribution of bone cement was 28.58%, which corresponded to a sensitivity and specificity of 72.2% and 91.7%, respectively. There was a strong correlation between the cement distribution score and VF% ( r  = 0.895, p  < 0.001). Conclusion BMD and VF% were important independent influencing factors of bone cement distribution. Extensive bone cement distribution can be achieved when the VF% reaches 28.58%.

Objective Given the recent application of two new types of intramedullary nail devices in the treatment of comminuted femoral intertrochanteric fractures (CFIFs), there is still a lack of deep understanding and comparative evaluation of their biomechanical properties. Therefore, this study aims to systematically compare the advantages and disadvantages of these two new devices with traditional proximal femoral nail antirotation (PFNA) and InterTan nails in the fixation of CFIFs through finite element analysis. Methods Based on the validated finite element model, this study constructed an accurate CFIFs model. In this model, PFNA, InterTan nails, proximal femoral bionic nails (PFBN), and new intramedullary systems (NIS) were implanted, totaling four groups of finite element models. Each group of models was subjected to simulation tests under a vertical load of 2100 N to evaluate the displacement and Von Mises stress (VMS) distribution of the femur and intramedullary nail devices. Results Under a vertical load of 2100 N, a comparative analysis of the four finite element models showed that the NIS device exhibited the most superior performance in terms of peak displacement, while the PFNA device performed relatively poorly. Although the NIS device had the highest peak stress in the femur, it had the smallest peak displacement of both the femur and intramedullary nail devices, and the peak stress was mainly concentrated on the lateral side of the femur, with significantly lower stress in the proximal femur compared to the other three intramedullary nail devices. In contrast, the PFBN device had the lowest peak stress in the femur, and its peak displacement of both the femur and intramedullary nail devices was also less than that of PFNA and InterTan nails. Conclusion This study demonstrates that in the treatment of CFIFs, PFBN and NIS devices exhibit superior biomechanical performance compared to traditional PFNA and InterTan nail devices. Especially the NIS device, which can achieve good biomechanical results when fixing femoral intertrochanteric fractures with missing medial wall. Therefore, both PFBN and NIS devices can be considered reliable closed reduction and internal fixation techniques for the treatment of CFIFs, with potential clinical application value.

Objective Patients with osteoporotic vertebral compression fractures (OVCF) treated with vertebroplasty (PVP) are experiencing an increasing number of problems such as pain recurrence, mainly due to recompression fractures of the operated vertebral body within a certain period of time after the operation, which is closely related to the distribution of intraoperative bone cement. The aim of this study is to investigate the effect of different spacing distributions between the upper boundary of the cement and the upper endplate of the operated vertebra on the biomechanics of the operated vertebra after percutaneous vertebroplasty for OVCF using finite element analysis (FEA). Methods One patient with L1 vertebral body OVCF was selected, and computed tomography (CT) of the thoracolumbar segment was performed. The CT data were extracted to establish an FEA model of the T12–L2 vertebral bodies. Bone cement was injected into the L1 vertebral body. Based on the spacing between the upper boundary of the bone cement and the vertebral body's upper endplates, the model vertebrae were divided into 0, 2, 4, and 6 mm spacing groups, and the human body's upright, flexion–extension, lateral flexion, and rotational positions were simulated. The biomechanical effects of different spacing distributions on the postoperative L1 vertebral body and the injected bone cement were evaluated. Results In this paper, we found that the Von Mises stress of the L1 vertebrae was the smallest when the spacing between the upper boundary of the bone cement and the vertebral body's upper endplates was 0 mm. The larger the spacing in a certain range between the upper boundary of the bone cement and the vertebral body's upper endplates, the greater the Von Mises stress of the L1 vertebrae. However, in the stress comparison of the injected bone cement, the Von Mises stress of the bone cement was greatest when the spacing between the upper boundary of the bone cement and the upper endplate of the vertebral body was 0 mm; the larger the spacing, the smaller the Von Mises stress. Conclusion When the contact spacing between the upper boundary of the bone cement and the upper endplate of the vertebral body is 0 mm, it can effectively eliminate and transfer the pressure caused by the load, thus reducing the stress on the cancellous bone and further reducing the risk of vertebral refracture after surgery. By establishing a finite element biomechanical model of surgical vertebral refracture after PVP in patients with OVCF, we found that when the contact spacing between the upper boundary of the bone cement and the vertebral body's upper endplates is 0 mm, the pressure generated by the load can be effectively eliminated and transmitted, thus reducing the stresses exerted on cancellous bone, and further reducing the risk of vertebral refracture in the postoperative period.

Background/Aims: Cullin 4A (CUL4A) is vital in cell survival, development, growth and cell cycle, it plays an important role in chaperone-mediated ubiquitination and interacts with TP53 in carcinogenesis. However, the clinicopathologic significance of CUL4A expression in colorectal cancer is unknown; in particular, the prognostic value of CUL4A combined with TP53 expression has not been explored. Methods: We analyzed the expression of CUL4A in both public database (Oncomine) and 180 cases of colorectal cancer and paired normal tissues by real-time polymerase chain reaction and western blotting. Colony formation, wound healing, migration and invasion assays and tumorigenesis in nude mice were used to explore the function of CUL4A in CRC proliferation and metastasis in vitro and in vivo. Markers of epithelial to mesenchymal transition (EMT) were evaluated by western blotting. Immunohistochemistry (IHC) was used to analyse the relationship between CUL4A expression and E-cadherin expression. Results: CUL4A and TP53 protein expression was significantly higher in cancerous tissues compared to normal tissues. Significant correlation between CUL4A and TP53 expression was observed. CUL4A expression was an independent prognostic factor for overall survival (OS) and disease-free survival (DFS). Interestingly, patients with tumors that had both CUL4A overexpression and mutant TP53 protein accumulation relapsed and died within a significantly short period after surgery (P < 0.001). Multivariate analysis showed that patients with both CUL4A+ and TP53+ positive tumors had extremely poor OS and DFS. Knockdown of CUL4A by a short interfering RNA (siRNA) significantly suppressed the progression of EMT, proliferation, migration, and invasion of colon cancer cells in vitro and tumor growth in vivo. ZEB1 silencing blocked CUL4A-driven these processes. Conclusion: CUL4A expression correlated positively with the prognosis of colorectal cancer. Mechanistically, ZEB1 was confirmed to mediate the function of CUL4A in regulating the EMT. The assessment of both CUL4A and mutant TP53 expression will be helpful in predicting colon cancer prognosis.

Background Many studies have combined sorafenib with transcatheter arterial chemoembolization (TACE) to treat patients with advanced hepatocellular carcinoma (HCC), but the results are disputable. Thus, we conducted this meta-analysis to assess the efficacy and safety of the combination treatment in patients with advanced HCC. Methods Clinical data were collected from a computer search of literature published from January 2009 to June 2016 in PubMed, Web of Science, the Cochrane Library, China National Knowledge Infrastructure (CNKI), Wan Fang and the China Science and Technology Journal Database (CSTJ). The final analysis included 14 studies and 1670 patients. The primary endpoints were overall survival (OS), the objective response rate (ORR) and the disease control rate (DCR). Results The combination group exhibited significantly more improvement than the group treated with TACE alone in ORR (RR =1.62, 95% confidence interval (CI) = 1.34–1.94, p  < 0.00001), DCR (RR = 1.43, 95% CI = 1.26–1.62, p  < 0.00001), 0.5-year OS (OR = 2.60, 95% CI = 1.57–4.29, p  = 0.0002) and 1-year OS (OR = 1.88, 95% CI =1.39–2.53, p  < 0.0001). The incidence of adverse events from combination therapy was increased compared to that from treatment with TACE alone, and the most commonly reported adverse events were fatigue, hand-foot skin reaction and diarrhoea, which were bearable. Conclusions The meta-analysis indicated that combination therapy is safe and efficient for clinical application.

Objective Bone cement leakage is a major complication of percutaneous vertebroplasty (PVP) while treating Kümmell's disease and it is a focus of close attention during the surgical procedure. The study aimed to investigate whether pre‐injecting a composite of bone cement and gelatine sponge (the “bone cement‐gelatine sponge composite”) before injecting bone cement during PVP aids in lowering the leakage rate in stage I and II Kümmell's disease. Methods This prospective analysis evaluated 74 patients with stage I and II Kümmell's disease who underwent PVP treatment at our hospital from December 2019 to December 2021. The participants were divided randomly into groups based on whether the bone cement‐gelatine sponge composite was used during the surgery. The two groups were the bone cement‐gelatine sponge composite group (GS group, comprising 37 patients) and the no bone cement‐gelatine sponge composite group (N‐GS group, comprising 37 patients). The independent samples t‐test and chi‐square test were employed to compare general information, operative time, cement injection volume, intraoperative bleeding, and bone cement leakage between the two groups. Additionally, the visual analogue scale (VAS) score, Oswestry disability index (ODI), anterior vertebral height ratio (AVHR), and the kyphotic Cobb angle were compared between the two groups at the preoperative, 2 days postoperative, and 6 months postoperative stages using repeated measures analysis of variance. Results All patients were followed up for more than 6 months, with an average of (11.19 ± 2.21) months. No significant differences were observed in terms of the operative time, cement injection volume, and intraoperative bleeding between the two groups (P > 0.05). The incidence of bone cement leakage in the N‐GS group (32.43%) was significantly higher than that in the GS group (5.41%), and the difference was statistically significant (P < 0.05). The VAS score and ODI of the two groups at postoperative 2 days and 6 months improved significantly (P < 0.05). The AVHR and kyphotic Cobb angle were corrected to a certain extent (P < 0.05); however, no significant difference was observed between the two groups (P > 0.05). Conclusion The bone cement‐gelatine sponge composite intravertebral prefilling technique can lower bone cement leakage in stage I and II Kümmell's disease and can also relieve pain and improve vertebral body height. The bone cement‐gelatin sponge composite can be tracked fluoroscopically within the vertebral body to precisely seal the fracture gap and can more effectively reduce cement leakage in stage I and II Kümmell's disease.

A reconfigurable logging and branch-lopping mechanism has been designed to shorten the production cycle, reduce work intensity, and improve labor survival rate in the logging industry. The mechanism integrating logging and branch-lopping functions can flexibly morph into three con-figurations, namely, series, parallel and mixed, as well as eight structure states to satiate different requirements. Not only does it possess sufficient stiffness to fell large trees but it also offers high flexibility to trim and crop small branches which superior performance has relatively wide engineering application prospects. The kinematics and static stiffness of the mechanism are the key techniques for its engineering application. With the mechanism as the research object, the working principles were analysed and the adjacency matrix of each structure state was presented. The Screw Theory and CGK formula were deployed to calculate the degrees of freedom of some of the structure mechanisms. The kinematics of some of the structure states was analysed and their flexibility matrices were obtained with vector algebra. The static stiffness of two structure states was compared indirectly by contrasting their flexibility matrices before their kinematics was simulated numerically. Engineering application of the mechanism in welding robots, robots that pick up objects, cleaning robots and other fields is demonstrated towards the end of this paper.

This thesis details the design, fabrication, and testing of an eddy current damper for a flexure-based nanopositioning stage, which is implemented within a μ-SLS 3D printer. Large conductor and back iron were included in the design to achieve large stage motion range coverage. High modularity of the design greatly reduced the potential damage to the stage during assembly. The integration of a linear stage with micron accuracy maximized the adjustability of the damper. To optimize the performance, a carbon fiber-foam structure was fabricated to minimize the added weight to the center stage by the damper. The performance tests of the stage reveal that the designed eddy current damper significantly lowers the overshoot and settling time of the stage. The closed-loop frequency response of the stage shows that the damper reduces the peak resonance of the stage while maintaining the bandwidth. These improvements are critical because it means the stage is less sensitive to disturbance without losing any response time. For a micro-SLS 3D printer application this means the potential for higher throughput.

The microstructure of the eutectic alloy Fe 30 Ni 20 Mn 35 Al 15 (in at.%) was modified by cooling at different rates from 1623 K, i.e., above the eutectic temperature. The lamellar spacing decreased with increasing cooling rate, and in water-quenched specimens lamellae widths of ~100 nm were obtained. The orientation relationship between the fcc and B2 lamellae was found to be sensitive to the cooling rate. In a drop-cast alloy the Kurdjumov–Sachs orientation relationship dominated, whereas the orientation relationship in an arc-melted alloy with a faster cooling rate was . The hardness increased with microstructural refinement, obeying a Hall–Petch-type relationship. The strength of the alloy decreased significantly above 600 K due to softening of the B2 phase.