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Cartilage is derived from the chondrogenic differentiation of stem cells, for which the regulatory mechanism has not been fully elucidated. N6-methyladenosine (m6A) messenger RNA (mRNA) methylation is the most common posttranscriptional modification in eukaryotic mRNAs and is mediated by m6A regulators. However, whether m6A regulators play roles in chondrogenic differentiation is unknown. Herein, we aim to determine the role of a main m6A reader protein, YTH N6-methyladenosine RNA binding protein 1 (YTHDF1), in chondrogenic differentiation regulation. Western blotting (WB) assays found that the expression of YTHDF1 increased during chondrogenic differentiation of human bone marrow mesenchymal stem cells (hBMSCs). The results of quantitative polymerase chain reaction, WB, immunohistochemistry, and Alcian blue staining revealed that overexpression of YTHDF1 increased cartilage matrix synthesis and the expression of chondrogenic markers when hBMSCs, ATDC5 cells, or C3H10T1/2 cells were induced to undergo chondrogenesis. Conversely, chondrogenesis was clearly inhibited when YTHDF1 was knocked down in hBMSCs, ATDC5 cells, or C3H10T1/2 cells. Further RNA sequencing and molecular biology experiments found that YTHDF1 activated the Wnt/β-catenin signaling pathway during chondrogenic differentiation. Finally, the effects of overexpression and knockdown of YTHDF1 on chondrogenic differentiation were reversed by inhibiting or activating β-catenin activity. Therefore, we demonstrated that YTDHF1 promoted chondrogenic differentiation through activation of the Wnt/β-catenin signaling pathway. [ABSTRACT FROM AUTHOR]

Study Design: A prospective study.Objective: The aim of this study was to investigate the factors associated with cardiopulmonary exercise testing (CPET) measurements in patients with adolescent idiopathic scoliosis (AIS).Summary Of Background Data: Patients with AIS display restrictive pulmonary dysfunction on pulmonary function testing (PFT). It remains unknown whether thoracic spinal deformity affects exercise performance.Methods: One hundred and sixty-eight patients with AIS from January 2014 to December 2019 were included. They underwent preoperative spinal radiological assessment, PFT, and CPET. The effects of the thoracic curve magnitude, body mass index, physical activity level and history of bracing on pulmonary function and exercise performance were analyzed. The Student t test and two-tailed Pearson test were used in data analysis.Results: We found significantly reduced forced expiratory volume in 1second (FEV1) in patients with a larger magnitude of the proximal thoracic curve (P < 0.001) and the main thoracic curve (P < 0.001). There was a negative correlation between forced vital capacity (FVC) and the magnitude of the main thoracic curve (P < 0.001) and thoracic hypokyphosis (P < 0.001). In CPET, exercise capacity indicators such as the work rate, peak oxygen intake, and heart rate were not affected by the thoracic curve magnitude. Patients with moderate or severe pulmonary dysfunction had decreased tidal volume (P = 0.01) and ventilatory reserve (P < 0.001), as well as increased respiratory frequency at maximal exercise (P = 0.01). Patients with a moderate or high physical activity level had better exercise capacity, which was reflected by a higher work rate (P = 0.009) and oxygen intake (P < 0.001).Conclusion: There was no significant correlation between radiographic parameters and exercise capacity indicators. When the thoracic curve increased, patients had restrictive ventilatory dysfunction, which led to a tachypneic breathing pattern and reduction of ventilatory reserve during exercise. A physiological change of improved peak oxygen intake was demonstrated in patients with a moderate or high physical activity level.Level of Evidence: 3. [ABSTRACT FROM AUTHOR]

Cu-free resin-based brake material filled with waste foundry resin-bonded sand (waste sand) was prepared using the hot-pressing method. The changes in the physical and chemical properties of Cu and waste sand during braking were investigated, and their role in resin-based composites was discussed. The effects of the content of waste sand on the hardness, impact strength, indentation hardness, elastic modulus, friction coefficient, wear rate, micro-scratch friction coefficient, scratch depth, residual depth, and wear mechanism of resin-based brake material were investigated. Cu-contained composites generate Cu 2 O when braking at high temperatures, which adversely affects the friction and wear properties. Compared to Cu, waste sand was found to be more favorable for the overall friction and wear properties of resin-based composites. This suggests that waste sand can be used as a substitute for Cu in brake material. Waste sand is beneficial for improving the friction coefficient and stability of brake material through the formation of a friction layer. This layer can significantly impact the wear mechanism of brake material, particularly at high temperature (250–350 ℃). The brake material with 10–15% waste sand indicates excellent heat-fade resistance. • Waste foundry sand have been successfully replaced copper in brake material. • The role of waste foundry sand and copper in brake material were comparatively studied. • The effects of waste sand on mechanical and tribological properties of brake material were investigated. • The brake material containing 10–15% waste foundry sand show excellent heat-fade resistance. [ABSTRACT FROM AUTHOR]

Study Design. A prospective study of cardiopulmonary function in patients with congenital scoliosis (CS). Objective. To investigate the relationship of thoracic cage deformity and exercise tolerance in CS patients. Summary of Background Data. Congenital thoracic scoliosis and chest deformity lead to restrictive pulmonary dysfunction and in some severe cases cause cardiopulmonary failure. However, it is still unknown the relationship between thoracic deformity and exercise performance. Methods. Patients with congenital thoracic spinal deformity were included and had radiological assessment of thoracic cage, pulmonary function testing, and cardiopulmonary exercise testing. Thoracic dimension including height, width, and depth were measured and geometry parameters were calculated. Two-tailed Pearson and Spearman correlation test and linear regression analysis were performed to investigate correlation of radiographic parameters, pulmonary function, and physical capacity. Results. Sixty patients (41 females and 19 males) were included, with an average age of 18.9 years. Patients with smaller thoracic height (P < 0.001) and width (P < 0.01) and larger depth (P < 0.05) had significantly worse static pulmonary function. In exercise testing, these patients showed significant tendency of ventilation insufficiency, including lower minute ventilation (P < 0.05), faster breathing frequency (P < 0.05), and smaller tidal volume (P < 0.01). Thoracic depth was negatively correlated to exercise capacity, reflected by work rate (P < 0.001), peak oxygen intake (P < 0.001), and heart rate (P = 0.043). Patients with abnormal thoracic geometry, especially a lower ratio of height to depth and a lower ratio of width to depth, have significantly worse static pulmonary function and exercise capacity (all P < 0.05). Conclusion. Decreasing thoracic height and width results in restrictive pulmonary dysfunction. Distortion and asymmetry of the thoracic cage are associated with abnormal breathing pattern and reduction of exercise capacity. Level of Evidence: 3 [ABSTRACT FROM AUTHOR]

Compare to the ICP (Iterative Closet Points) registration method and its variants, the registration method based on GMM (Gaussian Mixture Models) is less sensitive to initial position, noise and outliers. For efficiency in a large-scale point sets alignment, the algorithm involved with FGT (Fast Gaussian Transformation) was proposed. However, due to its accuracy degeneration, the application of fast implementation is limited in large-scale point registration. Thus a modified GMM method is established to improve its accuracy and efficiency in point sets registration. To improve the precision and robustness of point density, noise and outliers, the corresponding weight matrix consisted of bidirectional gauss distance is proposed in this study. Instead of FGT (Fast Gaussian Transformation), the IFGT (Improved Fast Gaussian Transformation) and an adaptive adjustment based on axis-angle is proposed to further improve its efficiency and robustness about initial position simultaneously. We test capabilities of methods in classical model and symmetric and featureless manufacture parts. Compared to state-of-the-art methods in experiment, the result demonstrated applicability of proposed method in real life. [ABSTRACT FROM AUTHOR]

In this paper, a comparative study is reported on tool wear morphology described by machining Be/Cu alloy at different cutting speed:200 m/min,400 m/min,600 m/min,800 m/min and 1000 m/min. The cemented tungsten carbide tools, both coated with TiAlN, are used to test tool life, and the flank wear extent and standard deviation are adopted to describe surface wear pattern. In order to explain the wear mechanism under different cutting speed, a series of theoretical calculation and experiment results were listed in this paper to explain adhesive effect on tool wear under different surface pressure, and results show that the adhesions and wear patterns would be affected by cutting speed and surface pressure. Comparing the relationship between cutting force, cutting heat, surface elements and tool wear, we can easily find out that the hard particle such as Cu and Be adhered to cutting edge to affect tool geometry and strengthen. Besides, the microstructure and generation probability are analyzed to discuss the crystal surface slipping effect on tool wear. • Due to unique adhesive effect, the wear process based on cutting speed is analyzed to optimize actual cutting process. • A temperature measurement method with artificial thermocouple is used to analyze variation as cutting speed increase. • The interaction effects of heat and force are analyzed in detail to explain the tool wear process. • The surface microstructure is used to analyze the possibility of tool damage. [ABSTRACT FROM AUTHOR]

Background: Patients with congenital scoliosis often have restrictive pulmonary dysfunction on static pulmonary function testing (PFT). Although frequently asymptomatic during daily activities, these patients are generally assumed to have reduced exercise capacity. The aim of this study was to use dynamic cardiopulmonary exercise testing (CPET) to investigate exercise capacity and its association with spinal deformity in patients with congenital scoliosis.Methods: Sixty patients with congenital scoliosis who underwent preoperative spinal radiography, PFT, and CPET were included from January 2014 to November 2017. The impact of thoracic spinal deformity and rib anomalies on pulmonary function and physical capacity was investigated.Results: A significant deterioration in pulmonary function with increases in the severity of the major thoracic curve was demonstrated by the forced expiratory volume in 1 second (FEV1), forced vital capacity (FVC), and total lung capacity (all p < 0.001). The ratio of FEV1 to FVC was similar regardless of thoracic curve severity. A smaller tidal volume during exercise testing reflected restrictive dysfunction in the patients with the most severe curves. CPET also revealed a significant trend of faster breathing by patients with a severe thoracic curve (p < 0.001). Exercise capacity indicators such as work rate (p = 0.019), heart rate (p = 0.015), and oxygen saturation (p = 0.006) were significantly reduced only in patients with a thoracic curve of >100°. Pulmonary dysfunction was the major contributor to exercise intolerance. Compared with mild pulmonary dysfunction, moderate and severe dysfunction was associated with an abnormal breathing pattern and lower work rate (p = 0.032) and peak oxygen intake (p = 0.042), indicating worse exercise tolerance.Conclusions: Congenital scoliosis leads to restrictive pulmonary dysfunction, which reduces the tidal volume and forces patients to accelerate respiratory rates during exercise. Patients with a thoracic curve of >100° are unable to compensate and have significantly reduced exercise capacity.Level Of Evidence: Prognostic Level II. See Instructions for Authors for a complete description of levels of evidence. [ABSTRACT FROM AUTHOR]

Background: Scoliosis causes impairment of the respiratory and cardiovascular systems. Traditional pulmonary function tests only examine patients under static conditions. The aim of our study was to investigate the correlation between radiographic parameters and dynamic cardiopulmonary capacity in patients with idiopathic scoliosis.Methods: Forty patients with idiopathic scoliosis were included in this prospective study from January 2014 to February 2016. The patients underwent full radiographic assessment of deformity, pulmonary function testing, and cardiopulmonary bicycle ergometer testing. The impact of the severity of thoracic curvature and kyphosis on pulmonary function and physical capacity was investigated.Results: Thirty-three female patients with a mean age of 15.5 years (range, 11 to 35 years) and coronal thoracic curvature of 49.4° (range, 24° to 76°) and 7 male subjects with a mean age of 15.9 years (range, 13 to 18 years) and coronal thoracic curvature of 47.1°(range, 22° to 80°) were included. No correlation was found between coronal thoracic curvature and pulmonary function test results in the female patients. Female patients with a thoracic curve of ≥60° had lower blood oxygen saturation at maximal exercise in the cardiopulmonary exercise test (p = 0.032). Female patients with a thoracic curve of ≥50° had a higher respiratory rate (p = 0.041) and ventilation volume per minute (p = 0.046) and lower breathing reserve at maximal exercise (p = 0.038). Thoracic kyphosis in female patients was positively correlated with pulmonary function, as shown by the forced expiratory volume in 1 second (r = 0.456, p = 0.01), forced vital capacity (r = 0.366, p = 0.043), vital capacity (r = 0.525, p = 0.006), and total lung capacity (r = 0.388, p = 0.031), as well as with tidal volume (r = 0.401, p = 0.025) in cardiopulmonary exercise testing. Female patients who engaged in regular exercise had better peak oxygen intake normalized by body weight (p < 0.001), peak oxygen intake normalized by the predicted value (p = 0.003), maximum heart rate (p = 0.020), and heart rate reserve (p = 0.014).Conclusions: Overall exercise tolerance was not correlated with the magnitude of the thoracic curve and kyphosis. Some parameters of ventilatory function and pulmonary gas exchange worsened as thoracic curvature increased or kyphosis decreased. Exercise capacity was better in patients who engaged in regular aerobic exercise, and physical activity is recommended for patients with idiopathic scoliosis.Level Of Evidence: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence. [ABSTRACT FROM AUTHOR]

Bulk unrelaxed alloys with compositions up to 65% and layer thicknesses up to 3 μm were grown by molecular beam epitaxy. The photoluminescence (PL) peak energy as low as 0.10 eV was demonstrated at T = 77 K. The electroluminescence and quantum efficiency data demonstrated with unoptimized barrier heterostructures from T = 80 to 150 K suggested large absorption and carrier lifetimes sufficient for the development of long wave infrared detectors and emitters with high quantum efficiency. The minority hole transport was found to be adequate for development of the detectors and emitters with large active layer thickness. [ABSTRACT FROM AUTHOR]

GaN-to-InGaN interface modification by predeposition of an ultrathin In-rich InGaN incomplete layer followed by a thin triangular InGaN well layer was employed to overcome the negative effects of polarization field on light emission efficiency of InGaN/GaN quantum wells as well as to improve the crystalline quality by avoidance of a significant strain generation and enhanced surfactant effect. Further, the interface modification induced energy band structure engineering reduces the spatial separation of electrons and holes, and thus increases the carrier recombination rate. The improvement in crystalline quality, localized potential fluctuation, and energy band engineering contribute to the significant increase of green emission of the InGaN/GaN quantum wells. [ABSTRACT FROM AUTHOR]

Industrial oily wastewater contains both light oil (ρ o i l < ρ w a t e r) and heavy oil (ρ o i l > ρ w a t e r) ; thus, there is a requirement to develop smart surfaces with reversible wettability as they possess the advantages of superhydrophobicity and superhydrophilicity. Herein, using a simple and convenient way of alternate immersion in stearic acid ethanol solution and THF, the wettability of the MR surface could be switched in a short duration to achieve reversible oil-water separation. (a) MR obtained by anodic oxidation was superhydrophilic, after being modified in a stearic acid ethanol solution for 30 min, the wettability was changed to superhydrophobic. At this point, oil could permeate its surface while water could not. (b) After the modified MR was soaked in THF for 30 min, the wettability was restored to superhydrophilic as well as underwater superoleophobic. At this time, water could penetrate its surface but water could not. The sewage treatment technology of oil-water separation based on superwetting materials has been widely employed. However, the stability of substrates was rarely considered in the past few years, which greatly limited the application of superwetting materials in engineering field. As a new robust, three-dimensional porous material, metal rubber (MR) has attracted significant attention for solving this problem. To treat the wastewater containing insoluble heavy/light oil and soluble dyes, herein, MR capable of degrading organic dyes with switchable wettability and high oil-water separation efficiency was prepared. Firstly, the superhydrophilic MR was obtained by anodizing. Then, the wettability of MR surface was reversibly switched between superhydrophilic and superhydrophobic via alternate immersion in stearic acid ethanol solution and tetrahydrofuran (THF) solvent to achieve switchable oil-water separation of MR. The superwetting MR displayed excellent abrasion resistance and retained outstanding oil-water separation performance after 100 times of sandpaper abrasion. Besides, the surface of pure titanium MR was rich in titanium dioxide (TiO 2) after anodic oxidation, which could effectively degrade the organic dyes under ultraviolet light. Therefore, the as-prepared superwetting MR possesses the ability to treat complex wastewater and have applications prospects in controllable oil-water separation and self-cleaning surfaces. [ABSTRACT FROM AUTHOR]

Tool wear is a major cause of accelerated tool failure during the milling of aluminum alloy. The periodically cutting force directly affect the cutting heat and tool wear due to the intermittent cutting characteristics of the milling process. The focus of this paper is to analyze the influence of the variation of cutting force on tool wear behavior. The change law of cutting force by cutting parameters was analyzed firstly. Secondly, the variation of the wear land width (VB) of tool flank face by the milling length was analyzed. Thirdly, the wear morphology and the energy dispersive spectrometer (EDS) results of tool rake face and flank face in different cutting parameters were observed by tungsten filament scanning electron microscope. Finally, considering the cutting force effect, the tool wear mechanism during high-speed milling of Aluminum-Alloy Die Castings 12 (ADC12, 12 means aluminum number 12) was analyzed. The cutting force in tangential direction is predominant during high-speed milling aluminum alloy, which decreases gradually with the increase of cutting speed but increases gradually with the feed rising. The adhesion-oxidation wear was main wear mechanism of tool rake face during high-speed milling. While adhesive wear was the main wear mechanism of the tool flank face during high-speed milling. It is found that the formation of adhesive wear is the process from particle adhesion to melting until the formation of adhesive layer, which related to the change of cutting force. [ABSTRACT FROM AUTHOR]

• Adhesive effect is selected to understand the trend of surface morphology. • Surface microstructures reflects the weakness of crystal structure of C-W-Co tool. • High-rate adhesive environment effectively reduces the friction environment. • Crystal adhesive hypothesis is proposed to describe tool damage process. Adhesive effect and sticking substances directly affects cutting process, tool life and geometry angle due to its randomness and unpredictability. This paper presents a single factor experiment based on adhesive rate variation trend and crystal adhesive hypothesis to understand the adhesive effect on tool damage. The results showed that the microstructures such as cracks, sticking substances and adhesive layer are the significant factor on tool damage process to make the coating more fragile and uncertain, and the adhesive effect appears a positive relationship with cutting performance, surface friction environment and wear life. [ABSTRACT FROM AUTHOR]

Facet joint osteoarthritis (FJOA) is associated with lumbar disc degeneration and has a significant role in the development of lumbar spinal stenosis (LSS). The relationship between various radiographic parameters and the grade of FJOA is not well understood. To explore radiographical parameters associated with FJOA in LSS without lumbar dynamic instability. Retrospective study analysis. A total of 122 patients diagnosed with LSS who visited our hospital between January 2015 and July 2022. We evaluated radiographic parameters of patients at L4-5 including lumbar lordosis (LL), pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS), grades of FJOA, facet joint orientation (FO), facet joint tropism (FT), intervertebral height index (IHI) and the relative cross-sectional area (RCSA) of paraspinal muscles. Patients diagnosed with LSS between January 2015 and July 2022 were enrolled. Demographic characteristics and radiographic parameters were collected. Spinopelvic parameters were measured through the preoperative lateral image of the whole spine, including LL, PI, pelvic tilt, and sacral slope. Lumbar computed tomography scan and magnetic resonance imaging were collected to measure the FO, FT, IHI, and the RCSA of paraspinal muscles respectively. Patients were divided into three groups according to the severity of FJOA graded by the Weishaupt classification: grade 0 and grade 1 were group A, grade 2 were group B, and grade 3 were group C. All variables were compared among the three groups, while the relationship between parameters and grades of FJOA were also analyzed. A total of 122 patients were included. PI was significantly greater in group C compared to group A (p = 0.025) and group B (p=0.022). FT was significantly greater in group C compared to group A (p<.001) and group B (p<.001). The RCSA of multifidus in group A were significantly greater than that in group B (p=0.02) and C (p=0.002). Additionally, FO in group C were significantly lower than group A (p<.001) and group B (p=0.028). The IHI in group C was significantly lower than group A (p=0.017). The correlation analysis indicated that grades of FJOA was positively related to Age, BMI (body mass index), PI, LL and FT, while negatively related to IHI, FO, RCSA of multifidus and RCSA of psoas major. Furthermore, the logistics regression showed that FT, PI, and IHI were important influence factors for FJOA. The current study confirmed that FT, PI and IHI were significantly associated with grades of FJOA at L4-5. Additionally, longitudinal studies are needed to understand the causal relationship between these parameters and FJOA. [ABSTRACT FROM AUTHOR]

[Display omitted] • A high-order nonlinear friction (HNF) model was proposed for the first time according to the inclination angle and contact form of the spatial distribution of metal wires in MR. • The HNF hysteresis dynamic model was constructed from which the NHF was the influence factor to adapt to the change of process parameters of metal rubber. • The probability function of three contact forms was constructed from the estimated parameters. And the transferred probability of three contact forms was analyzed under a harmonic excitation with 10 Hz. Metal rubber (MR) is a kind of porous and highly elastic pure metal damping material, but its strong nonlinear hysteresis characteristics are the main factors limiting its engineering application. In this paper, a high-order nonlinear friction (HNF) model was proposed for the first time according to the inclination angle and contact form of the spatial distribution of metal wires in MR. At the same time, combined with nonlinear elastic restoring force, nonlinear damping force, and coulomb hysteresis friction force, a general hysteresis dynamic model of MR was constructed. In order to verify the accuracy of the model, three kinds of MR with different densities were prepared and tested. The results show that the HNF hysteresis dynamic model has a very high prediction accuracy ( R 2 = 0.9999) and a high signal-to-noise ratio (SNR > 700). The hysteresis curve of the HNF hysteresis dynamic model was highly consistent with the experimental hysteresis curve, while the accuracy and versatility of the traditional dynamic model decreased with the change of density. It is because the HNF term includes the influence factors that can characterize the contact form of the metal wire inside MR and the material properties. These influence factors will be adjusted in real-time to reduce the error of the model according to the changes in the preparation process parameters or material properties. Therefore, the HNF hysteresis dynamic model could effectively demonstrate the nonlinear hysteresis characteristics of MR and had the adaptive ability to change process parameters. This paper provided a new theoretical model for the dynamic system of MR materials with a complex network structure. [ABSTRACT FROM AUTHOR]

Smart surfaces with responsive wettability are unstable, and depend upon continuous external stimuli, which limits their widespread application in switchable oil/water emulsions separations. In this study, a Ti‐based 3D porous structure (SLM‐3DTi) is printed using advanced selective laser melting (SLM) technology for the switchable separation of oil/water emulsion. With the assistance of the computer program, porous structure and re‐entrant texture can be easily designed and printed in one step. Without any continuous external stimulus, the wettability of SLM‐3DTi can be reversibly switched between underwater superoleophobicity and underoil superhydrophobicity simply by drying and washing cycles. The SLM‐3DTi achieves switchable surfactant‐stabilized oil‐in‐water emulsion (SSE(o/w)) and surfactants‐stabilized water‐in‐oil emulsion (SSE(w/o)) separation with purity above 99.8% at a flux of more than 2000 L m−2 h−1. In addition, the re‐entrant texture of the SLM‐3DTi surface is formed with the partially melting powder particles on the part contour, which has much stronger mechanical durability than any binder. Furthermore, SLM‐3DTi has excellent corrosion resistance due to the material properties of Ti. More importantly, based on the visualization analysis of the simulation, the mechanism of SLM‐3DTi emulsion separation is further elucidated. Therefore, SLM‐3DTi has broad practical application potential for high‐flux, high‐purity, and switchable oil/water emulsion separation. [ABSTRACT FROM AUTHOR]

As a novel lightweight metallic structure, metal rubber seals (MRS) can be used for sealing elements in extreme environments where traditional polymer rubber seals become ineffective. In the present work, a virtual fabrication technology (VFT) of MRS based on computer-aided simulation technology was developed to accurately reflect the random contact interface behavior between the disordered spiral network structure of MRS core and metal sheet. The mechanical properties (meso contact characteristics and macro structural response) of the complex structure were characterized by numerical analysis and compressive tests. The effect of the compression ratio and material porosity on contact pressure performances of sealing interface was analyzed in detail. It is found that the meso contact pressure of MRS is affected by the joint action of compression condition, inner core support and cladding failure. There is a turning point in a certain range, which allow the MRS prepared in this work has the relatively best contact characteristics when the porosity is 51.5% and the compression condition is 15%. The force-displacement curves obtained from simulation and experiment both exhibit an obvious nonlinearity and slow growth area, which confirm that the MRS constitutive model based on VFT can effectively characterize the multi-scale conformity of MRS specimens from meso-structure to macro-performance. [ABSTRACT FROM AUTHOR]

The purpose of this paper is to investigate the fatigue properties of C17200 alloy under the condition of quenching aging heat treatment at high temperatures, and to provide a design reference for its application in a certain temperature range. For this purpose, the tensile and rotary bending fatigue (RBF) tests were carried out at different temperatures (25 °C, 150 °C, 350 °C, and 450 °C). The tensile strength was obtained, and relationships between the applied bending stress levels and the number of fatigue fracture cycles were fitted to the stress-life (S-N) curves, and the related equations were determined. The fractured surfaces were observed and analyzed by a scanning electron microscopy (SEM). The results show that the RBF fatigue performance of C17200 alloy specimens is decreased with the increase in test temperature. When the temperature is below 350 °C, the performance degradation amplitudes of mechanical properties and RBF fatigue resistance are at a low level. However, compared to the RBF fatigue strength of 1 × 107 cycles at 25 °C, it is decreased by 38.4% when the temperature reaches 450 °C. It is found that the fatigue failure type of C17200 alloy belongs to surface defect initiation. Below 350 °C, the surface roughness of the fatigue fracture is higher, which is similar to the brittle fracture, so the boundary of the fracture regions is not obvious. At 450 °C, due to the further increase in temperature, oxidation occurs on the fracture surface, and the boundary of typical fatigue zone is obvious. [ABSTRACT FROM AUTHOR]

Study Design: A combined retrospective and prospective analysis on the therapeutic effect of physiotherapeutic scoliosis-specific exercise (PSSE) in mild juvenile idiopathic scoliosis (JIS) patients.Background: At present, patients with mild JIS are generally treated by observation without any interventional treatment. This study analyzed the effects of PSSE on mild JIS, which provided a new approach for the treatment of JIS.Method: A total of 52 patients with mild JIS (Cobb angle 10-19°), aged 4-9 years, self-selected into an observation group and a PSSE group. Patients performed the corrective posture exercises daily based on the Scientific Exercise Approach to Scoliosis (SEAS) to the best of their ability, and performed the over-corrective training based on Schroth methods for 30 min each day. Before and one year after the treatment, the Cobb angle and the angle of trunk rotation (ATR) were evaluated, and the results were compared between the two groups.Results: After one year of treatment, the Cobb angle in the PSSE group decreased from 15.0(11.0-17.0)° to 5.0(2.0-12.0)°(p ≤ 0.001), while the Cobb angle in the observation group increased from 13.5(11.0-17.3)° to 16.0(10.8-20.0)° (p = 0.010). The ATR in the PSSE group decreased from 5.0(2.0-7.0)° to 3.0(2.0-4.0)° (p = 0.009), while the change of ATR in the observation group was not significant. Compared with the observation group, 69.57% of patients in PSSE group had a decreased Cobb angle of more than 5 degrees, which was statistically significant(p ≤ 0.001).Conclusion: For mild JIS, PSSE decreased the Cobb angle and ATR. [ABSTRACT FROM AUTHOR]

Background: The treatment of severe and rigid scoliosis is challenging. We developed a surgical strategy for severe and rigid scoliosis since 2014. This study aimed to retrospectively analyze the safety and efficacy of apical region correction and global balance with 3 rods as a surgical strategy for the treatment of severe and rigid scoliosis.Methods: A retrospective study was performed for patients with severe and rigid scoliosis who underwent one-stage posterior corrective operation using the apical region correction and global balance with 3 rods surgical strategy between February 2014 and April 2020. The inclusion criteria were as follows: [1] Cobb angle > 90°; [2] flexibility < 30%; [3] a minimum 2-year follow-up. Patients were excluded if they had a history of traction or spinal surgery. Coronal and sagittal parameters, including Cobb angle, flexibility, apex vertebra translation, trunk shift (TS), thoracic kyphosis, lumbar lordosis, and sagittal vertical axis (SVA) were measured preoperatively, postoperatively and at the final follow-up. The Scoliosis Research Society 22-item questionnaire was administered preoperatively and at the final follow-up. During the operation, one slightly-bent short rod was placed into the concave side of apical region and correction was achieved by rod-rotation and distraction. Two pre-bent long rods were placed into both sides of the scoliosis and global balance was improved by leveling the proximal thoracic vertebrae and distal lumbar vertebrae.Results: A total of 41 patients were included, with an average age of 20 years (range, 12-49 years) and follow-up of 34 months (range, 24-58 months). Postoperative correction rate was 53% for scoliosis. There were 14 patients with normal kyphosis before surgery, and 28 patients with normal kyphosis at the last follow-up. 88% of the patients (23/26) with preoperative coronal imbalance (TS > 20 mm) restored coronal balance at the final follow-up. 87% of the patients (14/16) with preoperative sagittal imbalance (SVA > 40 mm) restored sagittal balance at the final follow-up. The mean operation time and blood loss were 286 min and 941 mL, respectively. No patients had neurological complications or implant failure.Conclusion: The surgical strategy of apical region correction and global balance with 3 rods is a safe and effective alternative for the surgical treatment of severe and rigid scoliosis. [ABSTRACT FROM AUTHOR]

[Display omitted] • A damage hysteresis dynamic model of tangled metal was proposed for analyzing the damage incurred by TMW under cycles. • The Damage hysteresis dynamic model was constructed from which the coupled relationship between micro-damage and macroscopic performance degradation in the TMW. This model provides insights into the dynamic damage and life prediction modeling of the TMW. • Based on the higher-order dry friction model that considers the internal structural characteristics and process parameters of TMW, this study further proposed a TMW damage hysteresis dynamic model that characterizes the evolution of internal damage in the TMW. Tangled metal wire (TMW) is a kind of porous hyperplastic high damping material, which can realize the vibration isolation of key equipment. However, the unclear mapping relationship between internal microscopic damage and overall macroscopic performance made it difficult to construct a damage hysteresis dynamic model. This limits the application and development of TMW vibration isolation. In this paper, a strategy to analyze the dynamic damage evolution of TMW was proposed. Firstly, a cross-scale relationship between internal damage in TMW and macroscopic performance degradation was established. Furthermore, a damage hysteresis dynamic model was constructed by considering the high-order dry friction (HDF). The complex spatial spiral structure and preparation process parameters were described by using the HDF. Then, the damage factors of each component force were built and analyzed: The damage factor of HDF could be used to characterize the damage evolution of the metal wire inside TMW and the cross-scale correlation between microscopic damage and macro performance degradation, whereas the degree of hysteresis characteristics of TMW could be characterized by the damage factor of hysteretic coulomb damper. Finally, the damage hysteresis dynamic model was evaluated through residual analysis, and it has high prediction accuracy in more than 80 % of the cycles R 2 > 0.7. This paper provided a new idea for the modeling of TMW life prediction. [ABSTRACT FROM AUTHOR]

Metamorphic heterostructures containing bulk InAs1-xSbx layers and AlInAsSb barriers were grown on GaSb substrates. The lattice mismatch (up to 2.1%) between the GaSb substrates and the InAsSb layers was accommodated by the growth of GaInSb linearly graded buffers. The 1 μm thick InAsSb0.44 layer with an absorption edge above 9 μm exhibited an in-plane residual strain of about 0.08%. InAs1-xSbx structures with x = 0.2 and x = 0.44 operated as light emitting diodes at 80 K demonstrated output powers of 90 μW and 8 μW at 5 μm and 8 μm, respectively. [ABSTRACT FROM AUTHOR]

Patients with spinal muscular atrophy (SMA) are susceptible to the respiratory infections and might be at a heightened risk of poor clinical outcomes upon contracting coronavirus disease 2019 (COVID-19). In the face of the COVID-19 pandemic, the potential associations of SMA with the susceptibility to and prognostication of COVID-19 need to be clarified. We documented an SMA case who contracted COVID-19 but only developed mild-to-moderate clinical and radiological manifestations of pneumonia, which were relieved by a combined antiviral and supportive treatment. We then reviewed a cohort of patients with SMA who had been living in the Hubei province since November 2019, among which the only 1 out of 56 was diagnosed with COVID-19 (1.79%, 1/56). Bioinformatic analysis was carried out to delineate the potential genetic crosstalk between SMN1 (mutation of which leads to SMA) and COVID-19/lung injury-associated pathways. Protein-protein interaction analysis by STRING suggested that loss-of-function of SMN1 might modulate COVID-19 pathogenesis through CFTR, CXCL8, TNF and ACE. Expression quantitative trait loci analysis also revealed a link between SMN1 and ACE2, despite low-confidence protein-protein interactions as suggested by STRING. This bioinformatic analysis could give hint on why SMA might not necessarily lead to poor outcomes in patients with COVID-19. [ABSTRACT FROM AUTHOR]

Background: Both patients with Chiari-I malformation (CIM) with syringomyelia and those with idiopathic syringomyelia (ISm) have a syrinx and can have scoliosis as well. However, there is no literature regarding differences between CIM and ISm in terms of radiographic outcomes and surgical complications after posterior fusion, to our knowledge. The aim of the present study was to compare radiographic features, clinical outcomes, and surgical complications after posterior spinal fusion between patients with CIM-associated scoliosis and those with ISm-associated scoliosis.Methods: One hundred and twenty patients with syringomyelia-associated scoliosis were retrospectively analyzed. Twenty-one patients with scoliosis secondary to CIM were enrolled and matched by sex, age, and the Cobb angle of the scoliotic curve with 21 patients with scoliosis secondary to ISm. All patients underwent 1-stage posterior fusion surgery. Coronal and sagittal radiographic parameters were evaluated before surgery, immediately after surgery, and at the final follow-up (at least 2 years). We also collected data regarding syringeal features, neurological deficits, intraoperative neuromonitoring, and complications.Results: Sex, age, preoperative coronal/sagittal scoliosis parameters, and neurological deficits were similar between the matched CIM and ISm groups. On average, the CIM group had a longer syrinx (12.3 ± 3.6 versus 8.9 ± 4.5 vertebral levels, p = 0.010) than the ISm group. The CIM and ISm groups showed similar correction rates for primary curves (70.9% ± 10.6% versus 69.5% ± 16.3%, p = 0.739). There were no significant differences in coronal/sagittal correction, intraoperative neuromonitoring abnormalities, surgical complications, or Scoliosis Research Society-22 questionnaire scores between the 2 groups.Conclusions: Despite matched demographic and scoliotic coronal parameters, patients with CIM had longer syrinxes compared with patients with ISm. One-stage posterior fusion achieved comparable clinical and radiographic outcomes for both CIM- and ISm-associated scoliosis without significant differences in neurological complications.Level Of Evidence: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence. [ABSTRACT FROM AUTHOR]

Study Design: Retrospective study.Objective: To compare syrinx characteristics, scoliotic parameters, and neurological deficits between Chiari I malformation (CIM) and idiopathic syringomyelia (IS) in the scoliotic population.Summary Of Background Data: CIM and IS are common in neuromuscular scoliosis patients; however, differences in syrinx characteristics, scoliotic parameters, and neurological deficits between CIM and IS are unclear.Methods: Thirty-six patients with scoliosis secondary to CIM were enrolled retrospectively and matched with 36 IS patients for sex, age, scoliosis classification, and Cobb angle. Information on radiographic features of scoliosis and syrinx and neurological deficits was systematically collected.Results: Sex, age, and coronal, and sagittal scoliosis parameters did not differ between the CIM and IS groups. The CIM group had a longer syrinx (12.9 ± 4.0 vertebral levels vs. 8.7 ± 5.5 vertebral levels, P < 0.001), a higher cranial extent (3.6 ± 2.2 vs. 5.2 ± 3.5, P = 0.027), and a lower caudal extent (15.6 ± 2.9 vs. 13.0 ± 4.6, P = 0.006) than the IS group, despite no differences in syrinx/cord (S/C) ratio or syrinx classification. No differences in neurological deficits were identified between the CIM and IS patients.Conclusion: With demographic and scoliotic coronal parameters matched, the CIM patients had a longer syrinx, located at a higher cranial and lower caudal level, compared with the IS group. No significant differences in syrinx S/C ratio, sagittal features of scoliosis, or neurological deficits were detected between the two groups.Level Of Evidence: 3. [ABSTRACT FROM AUTHOR]

In this study, a high-temperature fretting wear prediction model was established for metal rubber, which was then validated through experiments. Initially, a three-dimensional numerical model of metal rubber was reconstructed, and statistical distribution of contact points and types of curved wires inside the virtual component was achieved. Meanwhile, a high-temperature fretting wear evolution model for curved wires was constructed by introducing a temperature function f(T), considering material thermal expansion, softening, and oxidation. Subsequently, the model was incorporated into the macro model, establishing a cross-scale predictive model for wear from micro-coil elements to component wear. Experimental validation demonstrated good prediction performance of the model, with a maximum wear mass prediction error of 14.81% and prediction errors below 10% for 80,000 cycles. [ABSTRACT FROM AUTHOR]

• Metal wire and cotton fibers are combined through ingenious weaving methods. • The combination of macroscopic and microscopic fibers makes SWCM have excellent durability and efficient emulsion separation performance. • For the first time, an emulsion separation simulation model has been established via computational fluid dynamics (CFD) to understand the SWCM emulsion separation mechanism. • The separation efficiency of the SWCM is above 99.98% only by gravity drive. Superhydrophobic materials have been extensively investigated for their ability to separate oil/water mixtures, but their fragile durability has limited further development in this field. In this study, a durable superhydrophobic wire-cotton-based material (SWCM) was prepared by weaving metal wire and cotton fiber and modifying it with a mixed poly(vinyl phenol) (PVPh)/1,3-phenylene bisoxazoline (PBO) solution, which exhibits both macro-frame and micro-aperture. The SWCM demonstrates remarkable separation efficiency (greater than99.98 %) for a variety of water-in-oil emulsions using only gravity drive. More importantly, computational fluid dynamics (CFD) simulations were conducted to investigate the separation mechanism of SWCM, revealing dynamic trajectory and volume changes of water droplets in real-time. Moreover, the micro-aperture, protected by the macro-frame, can withstand hundreds of impacts and abrasions and still maintain reliable separation efficiency. Under the encapsulation of micro-apertures, the macro-frame exhibits excellent corrosion resistance and can maintain stable superhydrophobicity even after long-term immersion in different harsh solutions. Due to its excellent durability, the SWCM can maintain a long service life in oil–water separation in complex environments. Therefore, the presented SWCM has great potential in the development of durable and efficient materials for emulsion separation. [ABSTRACT FROM AUTHOR]

The interaction between adjacent asperities is a typical characteristic of the grinding process and plays an important role in the material removal mechanism. Therefore, in order to systematically investigate the formation mechanism of the subsurface damage, a precision grinding contact model between the diamond particle and optical glass with adjacent asperities is proposed in our research. The initiation and propagation mechanism of median/lateral cracks under residual stress, the propagation rules of the stress waves on the subsurface, and the interaction between the subsurface damage under stress superposition effect are fully investigated by a theoretical analysis and finite element simulation. The simulation results of the precision grinding model are verified by experiments, which show that the proposed numerical analysis model is reasonable and the finite element analysis process is feasible. [ABSTRACT FROM AUTHOR]

In this study, epoxy resin (EP) composites were prepared by using molybdenum disulfide (MoS2) and helical carbon nanotubes (H-CNTs) as the antifriction and reinforcing phases, respectively. The effects of MoS2 and H-CNTs on the friction coefficient, wear amount, hardness, and elastic modulus of the composites were investigated. The tribological properties of the composites were tested using the UMT-3MT friction testing machine, non-contact three-dimensional surface profilometers, and nanoindenters. The analytical results showed that the friction coefficient of the composites initially decreased and then increased with the increase in the MoS2 content. The friction coefficient was the smallest when the MoS2 content in the EP was 6%, and the wear amount increased gradually. With the increasing content of H-CNTs, the friction coefficient of the composite material did not change significantly, although the wear amount decreased gradually. When the MoS2 and H-CNTs contents were 6% and 4%, respectively, the composite exhibited the minimum friction coefficient and a small amount of wear. Moreover, the addition of H-CNTs significantly enhanced the hardness and elastic modulus of the composites, which could be applied as materials in high-temperature and high-pressure environments where lubricants and greases do not work. [ABSTRACT FROM AUTHOR]

Study Design: Retrospective radiographic study.Objective: To investigate the growth of the vertebrae around distal instrumented vertebra (DIV) in patients with early-onset scoliosis (EOS) who underwent dual growing rod (DGR) treatment.Summary Of Background Data: Previous studies indicated that DGR was likely to preserve or even stimulate the spinal growth. However, report pertaining to the effect of growing rod on the growth of individual vertebral body is rare.Methods: The EOS patients treated with DGR who had at least four lengthenings and 5-year follow-up were enrolled. Spine radiographs at index surgery and final follow-up were reviewed. The height, width, and depth of vertebral body from DIV-2 to DIV+2, and the height of the adjacent intervertebral space (IVS) were measured. The percentage of growth was calculated.Results: Thirty-one patients (mean age, 6.2 ± 2.5 years old) met the inclusion criteria, 74.2% (23/31) of whom were female. The average follow-up was 6.2 years (range, 5.0-10.4 yr). The measured vertebrae were divided into DIV group (n = 65), DIV- group (DIV-1 and DIV-2, n = 60), and DIV+ group (DIV+1 and DIV+2, n = 47). There were 33, 90, and 78 measured IVSs in DIV, DIV-, and DIV+ group, respectively. The total percentage growth of vertebral height was significantly higher in DIV- group than that in DIV and DIV+ groups (56.6 ± 20.3% vs. 45.6 ± 18.0% and 42.7 ± 16.2%, respectively, P ≤ 0.001). The vertebrae in DIV- group also had the highest annual height growth rate (8.7 ± 2.6% vs. 7.0 ± 2.4% and 6.6 ± 2.0%, respectively, P ≤ 0.001). A significant decrease of IVS height was observed in DIV- and DIV groups (P ≤ 0.001).Conclusion: Traditional DGR with periodical distraction stimulated the longitudinal growth of the two segments immediately above DIV in patients with EOS. DGR technique had a negative effect on the development of intervertebral discs within distracted levels.Level Of Evidence: 3. [ABSTRACT FROM AUTHOR]

Objective Scoliosis, especially thoracic curves, causes poor pulmonary function. As a result, scoliosis may impair sleep breathing. The literature regarding the relationship between scoliosis and sleep breathing is sparse. Methods Fifty-seven patients with adolescent idiopathic scoliosis or congenital scoliosis and 25 healthy control subjects were included. The wrist sleep monitors was used. Sleep breathing was evaluated with the following parameters: 1) Respiratory Disorders Index (pRDI), indicating mean respiratory events per hour of sleep including apnea, hypoxia, and respiratory effort–related arousal; 2) Apnea and Hypopnea Index (pAHI), expressing the number of apnea and hypopnea events per hour of sleep; and 3) mean and minimal oxygen saturation (Sa o 2) during sleep. Results No differences in age, sex distribution, and body mass index were found between the two groups. Patients with scoliosis had statistically significant higher pRDI (median, 10.10 vs. 8.65; P = 0.039) and pAHI (median, 1.60 vs. 0.72; P = 0.029) scores than the control group. The minimal SaO 2 value in patients with scoliosis was lower (median, 93% vs. 94%, respectively; P = 0.005), whereas no difference was found in the mean Sa O 2 value during sleep. In patients with scoliosis, pAHI scores were higher when lying on the convex side of the thoracic curve compared with the concave side (2.34 vs. 2.28, respectively; P = 0.044), whereas no such difference was observed in the control group. Conclusions Patients with scoliosis have more respiratory events of apnea and hypopnea during sleep than the control group. The minimal Sa O 2 value in patients with scoliosis is lower than the normal population. Sleeping on the convex side of the thoracic curve results in higher pAHI scores than on the concave side. Highlights • Scoliosis compromises sleep breathing of patients. • Patients with scoliosis have more respiratory events and related arousals. • Sleeping on the convex side of the thoracic curve results in more respiratory events. [ABSTRACT FROM AUTHOR]

Study Design: A prospective study.Objective: To investigate the incidence and risk factors of acute pancreatitis after scoliosis surgery.Summary Of Background Data: Pancreatitis has been recognized as a possible complication of extra-abdominal surgeries. However, there were few reports on the incidence and risk factors of acute pancreatitis after scoliosis surgery.Methods: A prospective clinical study was performed at our center from September 2014 to October 2015. One hundred seventy-six patients undergoing posterior spinal correction surgery were enrolled. The diagnosis of acute pancreatitis was based on their clinical manifestations combined with laboratory examination. Demographic, intraoperative, and radiological parameters were evaluated to identify the risk factors of acute pancreatitis after scoliosis surgery.Results: Thirteen patients (7.4%) were diagnosed with acute pancreatitis. Compared with patients without pancreatitis, pancreatitis patients had lower body mass index (BMI) (15.5 vs. 19.5, P = 0.001), larger preoperative Cobb angle of major curve (87.5° vs. 59.2°, P < 0.001), lower correction rate (57.4% vs. 69.0%, P = 0.045), lower intraoperative mean arterial pressure (57.9 mmHg vs. 66.1 mmHg, P < 0.001), and longer fusion levels (13.3 vs. 10.1, P < 0.001). No significant differences were noted with respect to operation time, intraoperative blood loss, or the amount of sagittal profile correction. Furthermore, multivariate logistic analysis revealed that BMI (odds ratio [OR] = 1.542, P = 0.009), lowest intraoperative mean arterial pressure (OR = 1.126, P = 0.039), and segments of fusion (OR = 0.551, P = 0.025) were independent risk factors for postoperative acute pancreatitis. All cases were treated with bowel rest, intravenous fluids, and fasting and completely recovered with 3.3 (2-5) days.Conclusion: The incidence of postoperative acute pancreatitis after scoliosis surgery was 7.4%. The low BMI, lowest intraoperative mean arterial pressure, and long segments of fusion were independent risk factors for acute pancreatitis after scoliosis surgery.Level Of Evidence: 3. [ABSTRACT FROM AUTHOR]

Study Design: A retrospective study.Objective: To compare the clinical outcomes of different surgical strategy for patients with congenital scoliosis (CS) and type I split cord malformation (SCM).Summary Of Background Data: CS associated with type I SCM is a challenge for spine surgeon because of the high potential rate of neurological compromise. Traditionally, bony spur resection (BR) has been indicated before any procedure for scoliosis correction.Methods: From May 2002 to February 2013, 82 CS patients with type I SCM who underwent corrective surgery at our center were retrospectively reviewed. There were 20 male and 62 female patients with an average age of 13.8 years (4-39 yrs) at surgery. They were divided into two groups according to different surgical strategy. The patients in the BR group underwent staged prophylactic neurosurgery or one-stage BR before corrective surgery, whereas patients in the nonresection (NR) group underwent one-stage corrective surgery without addressing bony spur.Results: There were 15 patients in the BR group and 67 patients in the NR group. No significant differences were detected in preoperative characteristics between two groups. The average follow up was 37 months (24-105 months). In the BR group, the correction rate was 53.0% and 45.9% at the final follow up. Whereas, in the NR group, the correction rate was 48.5% and 42.1% at the final follow up. Compared with the NR group, the operation time and blood loss were statistically higher in the BR group. Five patients experienced transient neurological complications and one patient in the BR group suffered permanent neurological damage of incomplete loss bladder control.Conclusion: One-stage corrective surgery could be safe and effective for patients with CS and SCM. For patients with intact or stable neurological status, prophylactic neurosurgical intervention to remove bony spur before curve correction may not be necessary.Level Of Evidence: 4. [ABSTRACT FROM AUTHOR]

InAs0.6Sb0.4/Al0.75In0.25Sb-based barrier photodetectors were grown metamorphically on compositionally graded Ga1-xInxSb buffer layers and GaSb substrates by molecular beam epitaxy. At the wavelength of 8 μm and T = 150 K, devices with 1-μm thick absorbers demonstrated an external quantum efficiency of 18% under a bias voltage of 0.45 V. [ABSTRACT FROM AUTHOR]

The main focus of current research in polymeric matrix brake composites is on searching out a replacement for copper, which has been recently proved to be a hazard to human health and the environment. In this paper, rare earth lanthanum oxide was explored for the replacement of copper in composites. The mechanism of the role of lanthanum oxide in brake composites to replace copper was analyzed. Four series of polymeric matrix brake composites with various amounts of copper (15, 10, 5 and 0 wt %) and rare earth lanthanum oxide (0, 5, 10 and 15 wt %) were developed, in which the copper was gradually replaced by lanthanum oxide in the formula. These series were characterized in terms of physical, thermo-physical and mechanical properties. The results show that lanthanum oxide can be successfully used as a replacement for copper in brake composites. Brake composites with 15 wt % lanthanum oxide that are copper-free are considered optimal, where tribo-properties are considered best. Compared with the addition of copper in brake composites, lanthanum oxide is more conducive to the formation of compacted friction films and transfer films, which is beneficial to the tribological properties of the brake composites. The addition of La2O3 to the brake composites can cause the reaction between La2O3 and Al2O3 to form LaAlO3, and the reaction between Al2O3 and BaSO4 can produce Ba18Al12O36 and Al2SO4 during the friction and wear processes, which can effectively improve the tribological properties of the brake composites at elevated temperature. This research was contributive to the copper-free, metal-free and eco-friendly brake composites. [ABSTRACT FROM AUTHOR]

In this work, a new and effective treatment on bamboo fiber (BF) is presented, and its effect on the interfacial bonding properties of the BF/resin matrix was studied. The interfacial functionary mechanism of rare earth solution (RES) modification to improve the interfacial bonding properties between BF and the resin matrix was analyzed. The hardness and elastic modulus of the interfacial zone between BF and the resin matrix were measured using nanoindentation. Fourier-transform infrared spectroscopy (FT-IR) was used to analyze the change in the surface functional group of BF in the modification process. The surface chemical composition of BF before and after the modification was characterized by X-ray photoelectron spectroscopy (XPS). The results show that the RES modification significantly increases the hardness and elastic modulus of BF and its interfacial zone with the resin matrix. The hydroxyl concentration on the surface of RES-treated BF decreases, which reduces the hydrophilicity of BF. Rare earth ions react with oxygen in the hydroxyl group at the C2 position in the glucosylic ring of cellulose. The RES-modified BF bonds with the resin matrix to form a rare earth complex, which significantly enhances the interfacial adhesion between BF and the resin matrix. [ABSTRACT FROM AUTHOR]