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Layer-by-layer (LbL) self-assembly combined with interfacial polymerization (IP) was utilized to prepare a separation bilayer composite nanofiltration (NF) membrane containing a polyelectrolyte (PE) sub-layer and a polyamide (PA) top-layer.

A series of mesoporous Ni–Cu/WO3/ZrO2 (1Ni1Cu/mWZr) was successfully prepared with F127 as a template and used as catalysts for isobutane hydroisomerization to n-butane. The effects of the F127/ZrO...

Electrochemical CO2 reduction is considered as a promising strategy for CO2 conversion and utilization. However, developing efficient and low-cost electrocatalysts still remains a great challenge. Herein, Ni–N@NPC was prepared using tobacco stem derived nitrogen-containing porous carbon (NPC) as a support and 1,10 phenanthroline as a chelating agent, as well as nickel(II) acetate tetrahydrate as a Ni source. The prepared Ni–N@NPC has highly dispersed Ni–N sites and good CO2 adsorption capacity. Ni–N@NPC exhibits excellent electrochemical CO2 reduction property, including high faradaic efficiency for CO (about 98.44%) at a medium overpotential of 670 mV and high activity (current density approximately 30.96 mA cm−2), as well as durable stability over 30 hours. In addition, the Ni–N@NPC still maintains a Faraday efficiency over 90.5% at wide potentials (from −0.57 V to −0.87 V). DFT calculation reveals that Ni–N sites decrease the kinetic energy barriers for *CO2 transition to *COOH, indicating that the high electrochemical CO2 reduction activity is attributed to the Ni–N sites in electrocatalysts. This work provides a new way to develop biomass carbon materials and promote their application in energy conversion.

Percutaneous vertebroplasty (PVP) via the unilateral posterosuperior approach has achieved good clinical results for the treatment of osteoporotic vertebral compression fractures. This study compared the biomechanical performance of a single vertebral body after PVP by the unilateral posterosuperior, unipedicular, and bipedicular approaches. Twenty-one vertebral bodies from the osteoporotic spine segments (T11-L1) of seven older female cadavers were randomly assigned to the unipedicular (group A), bipedicular (group B), or unilateral posterosuperior approach group (group C). After constructing the fracture compression model, PVP was performed by the different approaches. CT scans showed symmetrical, evenly distributed bone cement in groups B and C and unilaterally distributed cement in group A. The recovery rates of the anterior vertebral body height in groups B and C were significantly higher than those in group A after PVP (P0.05) and higher than those in group A (P

Background Injuries of the anterolateral ligament (ALL) are fairly common in patients with ruptures of the anterior cruciate ligament (ACL). Before considering repair or reconstruction of the ALL, the lack of knowledge with regard to the biomechanical behavior of this ligament must be considered. The purpose of this study was to analyze the strain of the ALL induced by tibial internal rotation at different flexion angles and find out the strain distribution features. Methods The ALLs of ten fresh-frozen cadaver knees were dissected. All specimens underwent tibial internal rotation from 0° to 25° at 30°, 60°, 90°, and 120° of knee flexion. Strain distribution of the ALL during internal rotation was recorded by digital image correlation (DIC). The overall strain and sub-regional strain were measured. Results The strain of the ALL increased with increasing tibial internal rotation. With 25° of internal rotation, the overall strain at each flexion angle was 12.89 ± 2.73% (30°), 15.32 ± 2.50% (60°), 18.94 ± 2.34% (90°), and 20.10 ± 3.27% (120°). The sub-regional strain was significantly different at all flexion angles. The strain of the distal 1/3 of the ALL was the greatest, followed by the middle 1/3, while the proximal 1/3 was the smallest (all P Conclusion The ALL resisted internal rotation of the tibia by becoming more tense with increasing rotation. A significantly high strain was observed in the distal portion near the tibial insertion site of the ALL, which may suggest that this region is prone to injury with excessive internal rotation.

This article explores the communist reconstruction project that transformed the famous Shanghai Racecourse into the complex of public space that now includes the Avenue of the People, People’s Square, and the People’s Park. It examines the case of the Shanghai horse racing track as an example of the larger Chinese Communist effort to embed political power into Shanghai’s physical space. By demolishing colonial-era landmarks and refashioning them into public space, the CCP hoped to establish legitimacy and win the hearts and minds of the Shanghainese. By inscribing political promises into concrete structures in the center of Shanghai, the CCP attempted to infuse the daily activities of city dwellers with the new rhetoric of nationalism, patriotism, and internationalism. We argue that the racecourse reconstruction did contribute to the realization of these goals, as the urban corollary to land reform, which ostensibly transferred land and the built environment from the clutches of “old-society” rulers into ...

Battery energy storage technology, with its fast and accurate power response, has become the focus of the auxiliary means of power system frequency modulation. However, the traditional simulation software lacks an accurate battery energy storage system component model, which affects the accuracy of analyzing the response characteristics of the energy storage system to a certain extent. This paper presents an electromechanical transient model of battery energy storage system without time delay, which considers the participation of energy storage system in frequency modulation dead zone and battery charging and discharging power. The control model is built based on the node current injection method by using the power system analysis integrated program, and the EPRI-7 standard system is selected for simulation analysis. The simulation results show that the model has good implant ability. And when the load is cut off in the power system, the energy storage system participating in frequency modulation can effectively maintain the frequency stability.

Since the use of electronic computers for power flow calculations in the mid-1950s, power flow calculation has been one of the most researched areas of power system problems, and a large number of research results have appeared. In addition to exploiting various special-purpose power flow calculation problems, these achievements are more specific algorithms that have been proposed in order to improve computing performance. The problem of power flow calculation is generally a problem of solving multivariate nonlinear algebraic equations in mathematics. It must be calculated by the method of stacking.

Aims The aim of this study was to compare the peak pull-out force (PPF) of pedicle-lengthening screws (PLS) and traditional pedicle screws (TPS) using instant and cyclic fatigue testing. Materials and Methods A total of 60 lumbar vertebrae were divided into six groups: PLS submitted to instant pull-out and fatigue-resistance testing (groups A1 and A2, respectively), TPS submitted to instant pull-out and fatigue-resistance testing (groups B1 and B2, respectively) and PLS augmented with 2 ml polymethylmethacrylate, submitted to instant pull-out and fatigue-resistance testing (groups C1 and C2, respectively). The PPF and normalized PPF (PPFn) for bone mineral density (BMD) were compared within and between all groups. Results In all groups, BMD was significantly correlated with PPF (r = 0.83, p < 0.001). The PPFn in A1 was significantly less than in B1 (p = 0.006) and C1 (p = 0.002). The PPFn of A2 was significantly less than in B2 (p < 0.001) and C2 (p < 0.001). The PPFn in A1, B1, and C1 was significantly greater than in A2 (p = 0.002), B2 (p = 0.027), and C2 (p = 0.003). There were no significant differences in PPFn between B1 and C1, or between B2 and C2. Conclusion Pedicle lengthening screws with cement augmentation can provide the same fixation stability as traditional pedicle screws and may be a viable clinical option. Cite this article: Bone Joint J 2018;100-B:516–21.

Background:Ligament repair and augmentation techniques can stabilize syndesmosis injuries. However, little is known about the mechanical behavior of syndesmotic ligaments. The aim of this study was to analyze full-field strain, strain trend under foot rotation, and subregional strain differences of the anterior inferior tibiofibular ligament (AITFL), posterior inferior tibiofibular ligament (PITFL), and interosseous membrane (IOM).Methods:Eleven fresh-frozen lower limbs were dissected to expose the AITFL, PITFL, and IOM. The foot underwent rotation from 0° to 25° internal and 35° external, with 3 ankle positions (neutral, 15° dorsiflexion, and 25° plantarflexion) and a vertical load of 430 N. Ligament strain was recorded using digital image correlation.Results:The mean strain on the AITFL with 35° external rotation was greater in the proximal portion compared with distal portion in the neutral position ( P = .009) and dorsiflexion ( P = .003). The mean strain in the tibial insertion and midsubstance near tibial insertion were greater when compared with other regions ( P = .018 and P = .009). The subregions of mean strain in the PITFL and IOM groups were not significantly different. The strain trend of AITFL, PITFL, and IOM showed common transformation, just when the foot was externally rotated.Conclusion:The findings of this study show that a significantly high strain was observed on the proximal part and the midsubstance near the Chaput tubercle of the AITFL when the ankle was externally rotated. All 3 ligaments resisted the torque in the syndesmosis by external rotation of the foot.Clinical Relevance:This study allows for better understanding of the mechanical behavior of the syndesmosis ligaments, which could influence the repair technique and AITFL augmentation techniques

In this thought-provoking interview, former Secretary Shultz shares his thoughts and experiences on many issues cornering crucial moments in Sino-American relations since the 1950s. His stories abo...

A thorough understanding of the long-term trends and extreme characteristics in the significant wave height (SWH) contributes greatly to coastal and offshore engineering activities and mitigation of marine disasters. In this study, the annual spatiotemporal variability of the SWH in the South China Sea (SCS) and the return periods for six locations are evaluated based on ERA5 wave reanalysis in a long time period (1950–2020). Long-term trends are estimated by using a popular non-parametric method, the Theil-Sen estimator, and then mapped to show the spatial variability of mean and extreme SWH. Basin-averaged analysis is also performed to investigate the general tendency of the mean SWH in the SCS, with an increasing rate of 0.11 cm/year. The well-known Mann-Kendall test is used to assess the significance of the trends. Significant positive trends in extreme SWH are mainly distributed in the eastern part of the central SCS around the Luzon Strait and the southwestern part of the SCS. In the extreme value analysis, by comparing 2 classical extreme value distribution models combined with 5 sampling methods, the Generalized Pareto Distribution incorporating the Peak Over Threshold (GPD-POT) method has turned out to be suitable for evaluating the return periods in the SCS based on 71-year SWH dataset. Extreme value analysis for different time lengths shows a correlation between the return level and the time span. Small and medium samples may lead to unstable parameter estimation and increased errors. The 100-year return values obtained by GPD-POT using the 71-year wave reanalysis are more credible at P1-P6 with 8.86, 11.79, 11.35, 10.52, 6.50 and 7.71 m, respectively. Both the estimated return periods and the number of extreme events quantified by the Method of Independent Storms (MIS) indicate that extreme events are closely related to the number of tropical cyclones. Seasonally, most extreme events in the SCS occur from June to December, with the summertime maximum SWH situated above the 15th degree of northern latitude and rapidly shifting to south in the fall.

Precise control of the size, composition, and assembly process of each component is expected to play a key role in the construction of integrated functional nanostructures. Herein we report a unique sacrificial template method for the fabrication of noble metal@silica hollow microspheres with noble metal (Au, Pt, and Pd) nanoparticles uniformly immobilized on the inner surfaces of silica hollow microspheres. A polystyrene microsphere as a sacrificial template is used to play dual roles, creating a cavity inside the silica microsphere and introducing noble metal nanoparticles into the silica microsphere. Distinct from the reported sacrificial template methods, this method takes advantage of a thermodynamic effect to easily deposit the noble metal nanoparticles with different sizes and compositions onto the template microspheres. In addition, taking Au@silica hollow microspheres for example, they exhibit excellent catalytic activity and recyclability for the reduction of p-nitrophenol (4-NP) by NaBH4.

This work presents a simple and straightforward approach to fabricating multifunctional nanocomposite particles which possess a core of a polystyrene (PS) particle, a transition layer of magnetic Fe3O4 nanoparticles (NPs), and an outer shell of adsorbable polyaniline (PANi). In detail, the positively charged Fe3O4 NPs synthesized via the chemical co-precipitation method are directly loaded onto the negatively charged surfaces of the PS particles obtained by emulsifier-free emulsion polymerization through electrostatic self-assembly; subsequently, the coating of the resultant PS/Fe3O4 nanocomposite particles with PANi was successfully achieved by virtue of the “swelling–diffusion–interfacial-polymerization method” (SDIPM). Furthermore, the adsorption of Cu2+ by PS/Fe3O4@PANi nanocomposite particles was investigated by changing the initial pH value, adsorption time, and initial concentration of the adsorbate. The adsorption data in our work follow a pseudo-second-order kinetics model and fit the Langmuir isotherm model. The PS/Fe3O4@PANi nanocomposite particles show that the maximum adsorption capacity is up to 181.5 mg g−1 at pH 5. More importantly, these nanocomposite particles can be easily recovered using an external magnetic field owing to the presence of Fe3O4 NPs, and the regenerated nanocomposite particles can be repeatedly used for eight cycles without significant loss of their adsorption capacity.

Wind power is random and intermittent, and large-scale wind power access will have a greater impact on the safe and stable operation of the power system. In order to study the influence of reactive power compensation device on the voltage stability of the doubly fed fan, this paper builds a system of IEEE14 node for the doubly fed asynchronous wind farm with SVC and STATCOM modules in MATLAB/PSAT and uses SVC in time domain simulation. It is applied to the wind power generation system separately from STATCOM, and analyzes the voltage stability under sudden changes in wind speed, three-phase short-circuit fault, and load sudden increase. The simulation results show that both SVC and STATCOM can improve the voltage stability of wind farm after grid disturbance, and STATCOM has better compensation stability than SVC.

Scholars have paid little attention to Maoist forces and legacies, and especially to the influences of Maoism on people's everyday dress habits during the Cultural Revolution. This article proposes that people's everyday clothing during that time – a period that has often been regarded as the climax of homogenization and asceticism – became a means of resistance and expression. This article shows how during the Cultural Revolution people dressed to express resistance, whether intentionally or unintentionally, and to reflect their motivations, social class, gender and region. Drawing on oral histories collected from 65 people who experienced the Cultural Revolution and a large number of photographs taken during that period, the author aims to trace the historical source of fashion from the end of the 1970s to the 1980s in Guangdong province. In so doing, the author responds to theories of socialist state discipline, everyday cultural resistance, individualism and the nature of resistance under Mao's regime.

Supplemental material, FAI753160-ICMJE for Strain Distribution in the Anterior Inferior Tibiofibular Ligament, Posterior Inferior Tibiofibular Ligament, and Interosseous Membrane Using Digital Image Correlation by Daorong Xu, Yibei Wang, Chunyu Jiang, Maoqing Fu, Shiqi Li, Lei Qian, Peidong Sun and Jun Ouyang in Foot & Ankle International

Our aim was to introduce a novel combined hemipelvic endoprosthesis for pelvic reconstruction after Enneking type I/II/IV resection and to evaluate the biomechanical properties of the endoprosthesis using finite element analysis.A three-dimensional finite element model of the postoperative pelvis was developed based on computed tomography (CT) images of the patient with the best post-operative limb function. A force of 400 N was applied along the longitudinal axis of the normal and post-operative pelvis for two positions: standing on two feet and sitting. Stress-distribution analysis was performed in both positions, and results were compared. Prosthesis improvements were simulated by intervertebral fusion and extra screw fixation.In the normal pelvis, stress distributions were mostly concentrated on the superior area of the acetabulum, arcuate line, sacroiliac joint and sacral midline in both static conditions, and peak stresses of 1.52 MPa and 4.53 MPa were observed at the superior area of the greater sciatic notch and ischial tuberosity, respectively. For the reconstructed hemipelvis, stress distributions were concentrated on the connecting rods of the acetabular component and the proximal segment of the pedicle rods, and peak stresses of 252 MPa and 213 MPa were observed on the proximal pedicle rods of the fourth lumbar vertebra for standing and sitting, respectively. Interbody fusion of the fourth and fifth lumbar vertebrae and extra screw fixation to the sacrum decreased the peak stresses by 33.0 % and 18.3 % while standing and by 10.8 % and 6.6 % while sitting.Reconstruction with combined hemipelvic endoprosthesis after types I/II/IV resection of the pelvis fulfilled physiological and biomechanical demands of the hemipelvis and yielded good biomechanical characteristics.

Biomechanical in vitro study.To determine whether the peak pull-out force (PPF) of cervical anterior transpedicular screw (ATPS) fixed in osteoporotic vertebrae positively influence screw stability or not before and after fatigue.Multilevel cervical spine procedures with osteoporosis can challenge the stability of current screw-and-plate systems. A second surgical posterior approach is coupled with potential risks of increased morbidity and complications. Hence, anterior cervical instrumentation that increases primary construct stability, while avoiding the need for posterior augmentation, would be valuable.Sixty formalin-fixed vertebrae at different levels were randomly selected. The vertebrae were divided into healthy controls (groups A1, A2), osteoporotic controls (B1, B2), healthy ATPS groups (C1, C2), osteoporotic ATPS groups (D1, D2), and osteoporotic restoration controls (E1, E2). The procedure of ATPS insertion was simulated with 2 pilot holes being drilled on each side of 20 vertebral bodies that were implanted with either vertebral screw or polymethylmethacrylate. Each side randomly received either instant PPF or PPF beyond fatigue (2.5 Hz; 20,000 times).The prefatigue PPFs were significantly higher than the postfatigue PPFs in all groups (group A: 366.06 ± 58.78 vs. 248.93 ± 57.21 N; group B: 275.58 ± 23.18 vs. 142.79 ± 44.78 N; group C: 635.99 ± 185.28 vs. 542.57 ± 136.58 N; group D: 519.22 ± 122.12 vs. 393.16 ± 192.07 N, and group E: 431.78 ± 75.77 vs. 325.74 ± 95.10 N). The postfatigue PPFs were reduced by 32.00% (group A), 48.19% (group B), 14.69% (group C), 24.28% (group D), and 24.72% (group E). The acute and postfatigue PPFs of both control groups were significantly lower than that of ATPS groups (P0.05). The cyclic osteoporosis ATPS group achieved the same PPF compared with the vertebral restoration screw group.The findings of this study suggest that instant PPF and fatigue resistance capability of an ATPS fixation were significantly better than other control groups, especially in the osteoporotic vertebrae.

Herein an in situ growth of clean palladium nanoparticles (Pd NPs) on functional reduced graphene oxide (RGO)-coated polystyrene (PS) microspheres is achieved by a simple two-step process. On the basis of the hydrophobic interaction and π-electron interaction, the PS/RGO composite particles are first prepared by the reduction of graphene oxide in the presence of PS microspheres. Second, without using any additional reducing agent or stabilizer, the clean Pd NPs grow in situ on the surface of PS/RGO composite particles in water through a spontaneous redox reaction between Pd2+ and RGO. Significantly, owing to the stabilizer-free surface of Pd NPs and the synergistic effect of RGO and Pd NPs, the resultant PS/RGO@Pd composite particles feature pronounced catalytic activity toward the reduction of p-nitrophenol and Suzuki coupling reactions. Moreover, the catalyst particles can be easily recovered by centrifugation because of the large size of support microspheres and recycled consecutively.

A finite element model was used to compare the biomechanical properties of a novel anterior transpedicular screw artificial vertebral body system (AVBS) with a conventional anterior screw plate system (ASPS) for fixation in the lower cervical spine. A model of the intact cervical spine (C3–C7) was established. AVBS or ASPS constructs were implanted between C4 and C6. The models were loaded in three-dimensional (3D) motion. The Von Mises stress distribution in the internal fixators was evaluated, as well as the range of motion (ROM) and facet joint force. The models were generated and analyzed by mimics, geomagic studio, and ansys software. The intact model of the lower cervical spine consisted of 286,382 elements. The model was validated against previously reported cadaveric experimental data. In the ASPS model, stress was concentrated at the connection between the screw and plate and the connection between the titanium mesh and adjacent vertebral body. In the AVBS model, stress was evenly distributed. Compared to the intact cervical spine model, the ROM of the whole specimen after fixation with both constructs is decreased by approximately 3 deg. ROM of adjacent segments is increased by approximately 5 deg. Facet joint force of the ASPS and AVBS models was higher than those of the intact cervical spine model, especially in extension and lateral bending. AVBS fixation represents a novel reconstruction approach for the lower cervical spine. AVBS provides better stability and lower risk for internal fixator failure compared with traditional ASPS fixation.

Study design An experimental study. Objective To compare the peak pull-out force (PPF) of vertebral screws fixed in osteoporotic vertebrae versus polymethylmethacrylate (PMMA) used for augmentation or restoration, before and after fatigue. Summary of background data Failure of screw fixation in anterior cervical interbody fusion remains a significant clinical problem. However, little is known of the biomechanical characteristics of cervical vertebral screws before and after restoration or augmentation, especially after fatigue. Methods Fifty fresh cervical vertebrae, of which 40 were randomly selected, from 12 adult cadavers were used. The vertebrae were divided into healthy controls, osteoporotic controls, a PMMA restoration group, and a PMMA augmentation group. In each of the control groups, 2 pilot holes on each side of 20 vertebral bodies were implanted with vertebral screws (4 mm in diameter). Each side randomly received either acute PPF or PPF beyond fatigue that was ensured using cyclic loading (2 Hz; 20,000 times). In the PMMA groups, pilot holes were drilled parallel to the sagittal plane and injected with 0.6-1.0 mL PMMA before the vertebral screw was inserted. Each side of each vertebral body randomly received either PPF or PPF beyond fatigue that was ensured using cyclic loading (2 Hz; 20,000 times). A Bose3510-AT fatigue testing machine measured the PPF of vertebral screws with or without PMMA for all specimens before and after fatigue. Results In all groups, the prefatigue PPF was significantly higher than the postfatigue PPF. Compared with the prefatigue PPF, postfatigue PPF was reduced by 37.40%, 43.10%, 32.08%, and 31.85% in the healthy controls, osteoporotic controls, PMMA restoration, and PMMA augmentation groups, respectively. The acute and postfatigue PPFs of the healthy controls were significantly higher from that of the osteoporotic controls. The acute and postfatigue PPFs of both control groups were significantly lower from that of both PMMA groups. There was no difference in acute and postfatigue PPFs between the PMMA restoration and augmentation groups. Conclusions The results indicated that both PMMA augmentation and PMMA restoration could significantly increase cervical screw pull-out strength and antifatigue capability. The results provide a biomechanical justification for spine surgeons to use PMMA for augmentation or restoration in cases of surgeries with poor bone quality or osteoporotic vertebral bodies.

The impact force applied to the greater trochanter during sideways fall is a critical factor for determining whether or not a hip fracture would occur. However, the impact force is subject-dependent as it is related to the subject’s anthropometric parameters and the kinematic variables in fall. It cannot be accurately predicted by the currently available dynamics models. We developed and validated a method for constructing subject-specific dynamics models to more accurately predict the impact force. The anthropometric parameters required in the model were obtained from the subject’s whole body DXA (dual energy X-ray absorptiometry) image. The subject-specific dynamics models were then validated by protected fall tests using young volunteers. The effects of anthropometric parameters on the impact force were investigated using 90 clinical DXA images obtained from a local osteoporosis clinic center. The impact forces predicted by subject-specific dynamics models had much better agreement with the experimenta...

Sideways fall has been identified as the most critical situation for the elderly to develop hip fractures. The impact force onto the greater trochanter is the key factor for predicting fracture risk. For the elderly, the impact force can only be determined by dynamics simulations, and the dynamics model must be first validated by experiments before it can be applied in clinic. In this study, subject-specific whole-body dynamics models constructed from dual energy X-ray absorptiometry (DXA) images of the subjects were validated by controlled and protected fall tests using young volunteers. The validation results suggested that subject-specific dynamics model is much more accurate in predicting impact force induced in sideways fall than conventional non-subject-specific dynamics model. Therefore, subject-specific dynamics model can be applied in clinic to improve the accuracy of assessing hip fracture risk.

BACKGROUND As an environmentally benign particle emulsifier, starch nanocrystal (SNC) has attracted considerable attention. By submitting waxy maize starch to acid below the gelatinisation temperature of starch, nanoscale crystalline residues, which are SNCs, were separated from starch granules by hydrolysing amorphous regions. The SNC could be used as a particle emulsifier to stabilise emulsions. RESULTS The SNC could adsorb at the oil–water interface to stabilise oil-in-water emulsions with high stability to coalescence. The creaming of emulsions occurred after homogenisation but decreased with increasing SNC content, which was mainly due to the formation of an inter-particle network in the emulsions. Because of the amount of sulfuric groups at the surface, the SNC was negatively charged. Therefore, at low pH values or high salt content the electrostatic repulsion of the SNC was reduced, which further caused droplet aggregation and an increase in size of the particles in the emulsions stabilised by the SNC. CONCLUSION The SNC was an efficient particle emulsifier for preparing Pickering emulsions. The size of emulsions stabilised by the SNC could be tailored by changing the pH value or salt concentration. © 2013 Society of Chemical Industry

The surface properties of native starch, namely rice, waxy maize, wheat and potato starch were characterized by contact angle measurement, zeta-potential, and then the emulsifying ability of these native starch granules was investigated by using liquid paraffin as oil phase and starch granules as sole emulsifier. It was found that emulsions could be prepared by using rice, waxy maize and wheat starch granules as emulsifier, but not potato starch, which had no emulsifying ability even when the concentration of starch granules as high as 15 wt% relative to water phase. Rice starch was the best emulsifier among these native starches. The emulsion stabilized by rice granules proved to be stable to coalescence for several months when the starch concentration was above 3 wt% relative to water phase. With the increasing of the rice starch concentration, the sizes of droplets decreased and the stability of emulsions enhanced. The salt and pH values had no significant influence on the packing structure of native starch granules at interface.

The year 2016 marks the 50th anniversary of the launch of the Cultural Revolution in China, where controversy continues to rage over its meaning and its legacies. The Communist Party’s unequivocal condemnatory labelling of the entire movement as“a grave‘left’ error…responsible for the most severe setback and the heaviest losses suffered by the Party, the state and the people since the founding of the People’s Republic” has remained in place since 1981. Yet, even decades after the Party’s official resolution, the Cultural Revolution remains a lightning rod for contention, particularly in Chinese cyberspace. As a result, in March 2016, with the anniversary of the start of the Cultural Revolution still months away, the Party tabloid, Global Times (Huanqiu shibao环球时报), issued an ominous warning against “small groups” that might seek to generate “a totally chaotic misunderstanding of the Cultural Revolution.”The editorial sternly remindedGlobal Timesreaders that“discussions strictly should not depart from the Party’s decided politics or thinking,” a prohibition that appears to have short-circuited both popular discussion and scholarly reflection on this critical watershed in 20th-century Chinese politics.

Objectives Many studies have investigated the kinematics of the lumbar spine and the morphological features of the lumbar discs. However, the segment-dependent immediate changes of the lumbar intervertebral space height during flexion-extension motion are still unclear. This study examined the changes of intervertebral space height during flexion-extension motion of lumbar specimens. Methods First, we validated the accuracy and repeatability of a custom-made mechanical loading equipment set-up. Eight lumbar specimens underwent CT scanning in flexion, neural, and extension positions by using the equipment set-up. The changes in the disc height and distance between adjacent two pedicle screw entry points (DASEP) of the posterior approach at different lumbar levels (L3/4, L4/5 and L5/S1) were examined on three-dimensional lumbar models, which were reconstructed from the CT images. Results All the vertebral motion segments (L3/4, L4/5 and L5/S1) had greater changes in disc height and DASEP from neutral to flexion than from neutral to extension. The change in anterior disc height gradually increased from upper to lower levels, from neutral to flexion. The changes in anterior and posterior disc heights were similar at the L4/5 level from neutral to extension, but the changes in anterior disc height were significantly greater than those in posterior disc height at the L3/4 and L5/S1 levels, from neutral to extension. Conclusions The lumbar motion segment showed level-specific changes in disc height and DASEP. The data may be helpful in understanding the physiologic dynamic characteristics of the lumbar spine and in optimising the parameters of lumbar surgical instruments. Cite this article: M. Fu, Q. Ye, C. Jiang, L. Qian, D. Xu, Y. Wang, P. Sun, J. Ouyang. The segment-dependent changes in lumbar intervertebral space height during flexion-extension motion. Bone Joint Res 2017;6:245–252. DOI: 10.1302/2046-3758.64.BJR-2016-0245.R1.

Waxy maize starch was hydrolyzed with sulfuric acid in aqueous solution. The remaining starch granules after acid hydrolysis were characterized by TEM and wide-angle XRD. Starch nanocrystals with size between 40 to 80 nm and relative crystallinity of 63% were obtained after 6 days of hydrolysis. Starch nanocrystals/carboxymethyl chitosan composite films were prepared by casting-evaporation method. When the starch nanocrystals content was below 30 wt%, the filler dispersed uniformly in the carboxymethyl chitosan matrix, whereas aggregation of starch nanocrystals and phase separation between aggregates and matrix were observed when the starch nanocrystals content was higher than 30 wt%. The maximum tensile strength (TS) of composite films approached ∼29 MPa, which was two times higher than that of the carboxymethyl chitosan film without filling starch nanocrystals. The percentage elongation at break (EB%) of nanocomposite films decreased with the increasing of the starch nanocrystals content. The water absorption and water vapor barrier property of carboxymethyl chitosan film were significantly improved by adding starch nanocrystals.

To compare the biomechanical properties of the anterior transpedicular screw-artificial vertebral body (AVB) and conventional anterior screw plate system (AP) in lower cervical spine by finite element study.CT images (C1-T1) were obtained from a 38-year-old female volunteer. The models of intact C(3-7) (intact group), AP fixation (AP group), and AVB fixation (AVB group) were established and analyzed by Mimics 14.0, Geomagic Studio 2013, and ANSYS 14.0 softwares. The axial force of 74 N and moment couple of 1 N x m were loaded on the upper surface and upper facet joint surfaces of C3. Under conditions of flexion, extension, lateral bending, and rotation, the Von Mises stress distribution regularity and maximum equivalent stree of AP and AVB groups were recorded, and the range of motion (ROM) was also analyzed of 3 groups.The intact model of lower cervical spine (C(3-7)) was established, consisting of 286,382 elements and 414,522 nodes, and it was successfully validated with the previously reported cadaveric experimental data of Panjabi and Kallemeyn. The stress concentrated on the connection between plate and screw in AP group, while it distributed evenly in AVB group. Between AP and AVB groups, there was significant difference in maximum equivalent stress values under conditions of 74 N axial force, flexion, extension, and rotation. AVB group had smaller ROM of fixed segments and larger ROM of adjacent segments than AP group. Compared with intact group, whole ROM of the lower cervical spine decreased about 3 degrees, but ROM of C(3,4) and C(6,7) segments increased nearly 5 degrees in both AP and AVB groups.As a new reconstruction method of lower cervical spine, AVB fixation provides better stability and lower risk of failure than AP fixation.

As an environmentally benign particle emulsifier, starch nanocrystal (SNC) has attracted considerable attention. By submitting waxy maize starch to acid below the gelatinisation temperature of starch, nanoscale crystalline residues, which are SNCs, were separated from starch granules by hydrolysing amorphous regions. The SNC could be used as a particle emulsifier to stabilise emulsions.The SNC could adsorb at the oil-water interface to stabilise oil-in-water emulsions with high stability to coalescence. The creaming of emulsions occurred after homogenisation but decreased with increasing SNC content, which was mainly due to the formation of an inter-particle network in the emulsions. Because of the amount of sulfuric groups at the surface, the SNC was negatively charged. Therefore, at low pH values or high salt content the electrostatic repulsion of the SNC was reduced, which further caused droplet aggregation and an increase in size of the particles in the emulsions stabilised by the SNC.The SNC was an efficient particle emulsifier for preparing Pickering emulsions. The size of emulsions stabilised by the SNC could be tailored by changing the pH value or salt concentration.

Background Accurate placement of pedicle screw during Anterior Transpedicular Screw fixation (ATPS) in cervical spine depends on accurate anatomical knowledge of the vertebrae. However, little is known of the morphometric characteristics of cervical vertebrae in Chinese population. Methods Three-dimensional reconstructions of CT images were performed for 80 cases. The anatomic data and screw fixation parameters for ATPS fixation were measured using the Mimics software. Findings The overall mean OPW, OPH and PAL ranged from 5.81 to 7.49 mm, 7.77 to 8.69 mm, and 33.40 to 31.13 mm separately, and SPA was 93.54 to 109.36 degrees from C3 to C6, 104.99 degrees at C7, whereas, 49.00 to 32.26 degrees from C4 to C7, 46.79 degrees at C3 (TPA). Dl/rSIP had an increasing trend away from upper endplate with mean value from 1.87 to 5.83 mm. Dl/rTIP was located at the lateral portion of the anterior cortex of vertebrae for C3 to C5 and ipsilateral for C6 to C7 with mean value from −2.70 to −3.00 mm, and 0.17 to 3.18 mm. The entrance points for pedicular screw insertion for C3 to C5 and C6 to C7 were recommended −2∼−3 mm and 0–4 mm from the median sagittal plane, respectively, 1–4 mm and 5–6 mm from the upper endplate, with TPA being 46.79–49.00 degrees and 40.89–32.26 degrees, respectively, and SPA being 93.54–106.69 degrees and 109.36–104.99 degrees, respectively. The pedicle screw insertion diameter was recommended 3.5 mm (C3 and C4), 4.0 mm (C5 to C7), and the pedicle axial length was 21–24 mm for C3 to C7 for both genders. However, the ATPS insertion in C3 should be individualized given its relatively small anatomical dimensions. Conclusions The data provided a morphometric basis for the ATPS fixation technique in lower cervical fixation. It will help in preoperative planning and execution of this surgery.

An understanding of the load transfer within spinal posterior column of lumbar spine is necessary to determine the influence of mechanical factors on potential mechanisms of the motion-sparing implant such as artificial intervertebral disc and the dynamic spine stabilization systems. In this study, a new method has been developed for evaluating the load bearing of spinal posterior column by the surface strain of spinal pedicle response to the loading of spinal segment. Six cadaveric lumbar spine segments were biomechanically evaluated between levels L1 and L5 in intact condition and the strain gauges were pasted to an inferior surface of L2 pedicles. Multidirectional flexibility testing used the Panjabi testing protocol; pure moments for the intact condition with overall spinal motion and unconstrained intact moments of ±8 Nm were used for flexion-extension and lateral bending testing. High correlation coefficient (0.967-0.998) indicated a good agreement between the load of spinal segment and the surface strain of pedicle in all loading directions. Principal compressive strain could be observed in flexion direction and tensile strain in extension direction, respectively. In conclusion, the new method seems to be effective for evaluating posterior spinal column loads using pedicles' surface strain data collected during biomechanical testing of spine segments.

To summarize the application and research status of the hip protector (HP) and to discuss the current problems and further research direction.HP related literature in recent years was reviewed and analyzed.Biomechanics experiment studies have shown that HP could protect hip joint from fractures caused by falling, however, the protective effect of HP has not shown clinically.HP biomechanical experiments show better protective effect, which may be related with the lower impact energy; in clinical application, poor compliance of HP is considered as the main reason of weak protective effect.

To evaluate the effect of polymethylmethacrylate (PMMA) augmentation on cervical stability after anterior cervical interbody fusion (ACIF) before and after fatigue.Twelve porcine cervical spines (C3-7) were subjected to testing angular displacement parameters, including the range of motion (ROM), neutral zone (NZ), and elastic zone (EZ), in nondestructive flexion and extension, right/left lateral bending, and left/right rotation on Motion Analysis motion capture system and MTS-858 servo-hydraulic testing machine. Intact cervical spines served as control group (group A); one-level discectomy and fusion was performed with anterior plate fixation based on group A as group B; flexion and extension, left/right lateral bending (5 000 cycles) fatigue testing based on group B as group C; the augmentation screw channel was used based on group C as group D; and flexion and extension, left/right lateral bending fatigue testing were performed based on group D as group E.The ROM, NZ, and EZ in group A were significantly different from those in other groups (P0.05) at flexion/extension, left/right bending, and left/right rotation. The ROM, NZ, and EZ in group B were significantly smaller than those in group C (P0.05) in flexion/extension, left/right bending, and left/right rotation, but there was no significant difference when compared with group D (P0.05). The ROM and NZ in flexion/extension and the EZ in flexion in group B were significant smaller than those in group E (P0.05), but there was no significant difference in the other indexes (P0.05). The ROM, NZ, and EZ in group C in flexion and extension, left/right lateral bending, and left/right rotation were significantly higher than those in groups D and E (P0.05). The ROM and NZ in flexion and extension and left/right lateral bending, and the ROM in left/right rotation, and the EZ in flexion and extension, right bending, and left/right rotation in group D were significantly smaller than those in group E (P0.05), but there was no significant difference in the other indexes (P0.05).PMMA augmentation can significantly increase the instant cervical stability and provide a biomechanics basis in cervical anterior plate fixation.

Understanding the load transfer within posterior column of lumbar spine is necessary to determine the influence of mechanical factors on potential mechanisms of the motion-sparing implant. The present study validated the effectiveness of the new strain gauge method for evaluating the posterior column load and it seems to be effective.