OBJECTIVE: To explore the clinical efficacy of high hip center technique total hip arthroplasty ï¼THAï¼ for Crowe â ¡and â ¢ developmental dysplasia of hip ï¼DDHï¼ and severe hip osteoarthritis ï¼HOAï¼. METHODS: From January 2018 to January 2020, 74 patients with Crowe typeâ ¡and â ¢ DDH and severe HOA were admitted, and 37 cases of anatomical hip center reconstruction were taken as control group, including 7 males and 30 females, aged from 42 to 65 years old with an average of ï¼58.40±4.98ï¼ years old, body mass index ï¼BMIï¼ ranged from 18 to 29 kg·m-2 with an average of ï¼23.02±2.21ï¼ kg·m-2. Thirty-seven routine high hip center technical reconstruction were performed as study group, including 5 males and 32 females, aged from 41 to 65 years old with an average of ï¼57.31±5.42ï¼ years old, BMI ranged from 18 to 29 kg·m-2 with an average of ï¼23.14±2.07ï¼ kg·m-2. The patients presented with hip pain, limited function and range of motion, and gait instability before surgery. All patients underwent THA, the control group underwent intraoperative anatomical hip center reconstruction, and the study group underwent intraoperative high hip joint reconstruction. The perioperative indicators of the two groups were compared. The hip joint function, balance function and gait of the patients were evaluated before surgery, 3 months, 6 months, and 12 months after surgery. The length difference of both lower limbs, horizontal distance of rotation center, vertical distance of rotation center and femoral eccentricity were measured before operation and 1 year after operation. The incidence of complications in the two groups during the operation and postoperative follow-up was counted. RESULTS: The operation time of the study group was shorter than that of the control group, and the intraoperative blood loss was less than that of the control group ï¼P<0.05ï¼. After 12-months follow-up, 1 was lost to followvup in study group and 2 were lost to follow-up in control group. The Harris scores and Berg balance scaleï¼BBSï¼, pace, stride frequency and single step length in the study group were higher than those in the control group at 3 months and 6 months after operation ï¼P<0.05ï¼ï¼there was no statistically significant difference between the two groups in the indexes 12 months after operation ï¼P>0.05ï¼. The vertical distance of the center of rotation of the study group was greater than that of the control group 12 months after operation ï¼P<0.05ï¼, and there was no significant difference in the length difference of the lower limbs, the horizontal distance of the center of rotation, and the femoral eccentricity between two groups ï¼P>0.05ï¼. There were no complications in either group. CONCLUSION: The long-term effects of THA in patients with DDH and severe HOA were similar between the two central hip reconstruction methods, and the safety was good, and the high hip central reconstruction technique could shorten the operation time and reduce the amount of intraoperative blood loss.At the same time, it has certain advantages in early recovery of hip joint function, balance function and walking function of patients.
Arthroplasty, Replacement, Hip , Hip Dislocation, Congenital , Osteoarthritis, Hip , Male , Female , Humans , Adult , Middle Aged , Aged , Arthroplasty, Replacement, Hip/methods , Osteoarthritis, Hip/surgery , Hip Dislocation, Congenital/surgery , Blood Loss, Surgical , Retrospective Studies , Treatment Outcome
In coupled identical oscillators, complete synchronization has been well formulated; however, partial synchronization still calls for a general theory. In this work, we study the partial synchronization in a ring of N locally coupled identical oscillators. We first establish the correspondence between partially synchronous states and conjugacy classes of subgroups of the dihedral group D_{N}. Then we present a systematic method to identify all partially synchronous dynamics on their synchronous manifolds by reducing a ring of oscillators to short chains with various boundary conditions. We find that partially synchronous states are organized into a hierarchical structure and, along a directed path in the structure, upstream partially synchronous states are less synchronous than downstream ones.
With the burgeoning of the microelectronics industry, in order to improve the transmission speed between chips in large-scale integrated circuits to meet the demands of high integration, it is necessary for interlayer insulation materials to possess a lower dielectric constant (k). Polyimide (PI) has been widely used as interlayer insulation materials for large-scale integrated circuits, and the exploration on reducing their dielectric constant has attracted extensive attention in recent years. In this work, porous PI-based composites with a low dielectric constant are mainly reviewed. The application of porous SiO2, graphene derivatives, polyoxometalates, polyhedral oligomeric silsesquioxane and hyperbranched polysiloxane in reducing the dielectric constant of PI is emphatically introduced. The key technical problems and challenges in the current research of porous polyimide materials are summarized, and the development prospect of low k polyimide is also expounded.
OBJECTIVE: To explore clinical effect of repairing anterior talofibular ligament with knot-free anchors under total ankle arthroscopy in treating chronic lateral ankle instability. METHODS: From April 2018 to August 2021, 24 patients with chronic lateral ankle instability were treated with knot-free anchors under total ankle arthroscopy to repair anterior talofibular ligament, including 16 males and 8 females, aged from 22 to 42 years old with an average of(28.6±5.8) years old;the time from injury to opertaion ranged from 6 to 10 months with an average of(7.7±1.3) months. Preoperative and postoperative American Orhopaedic Foot and Ankle Society (AOFAS) score, visual analogue scale (VAS), talar tilt, anterior talar translation(ATT) were recorded and compared. RESULTS: All patients were followed up from 10 to 12 months with an average of (10.2±1.14) months. Incision were healed at stageâ , and no infection, nerve injury and lateral ankle instability occurred. AOFAS score improved from(52.79±8.96) before opertaion to (93.00± 4.01) at 6 months after operation, 23 patients got excellent result and 1 good;VAS decreased from (5.50±0.98) before opertaion to (1.04±0.80) at 6 months after operation(P<0.05);talar tilt decreased from(9.16±2.09)° to (3.10±1.72)° at 3 months after operation(P<0.05);ATT decreased from(8.80±2.55) mm to (2.98±1.97) mm at 3 months after operation(P<0.05). Twenty-four patients drawer test and varus-valgus rotation wer negative. CONCLUSION: Repairing anterior talofibular ligament with knot-free anchors under total ankle arthroscopy for the treatment of chronic lateral ankle instability has advantages of less trauma, less complications safe and reliable, and good recovery of ankle joint function.
Joint Instability , Lateral Ligament, Ankle , Female , Male , Humans , Young Adult , Adult , Ankle Joint/surgery , Ankle , Arthroscopy , Lateral Ligament, Ankle/surgery , Joint Instability/surgery
Osteochondral defects threaten the quality of life of patients to a great extent. To simulate gradient changes in osteochondral tissue, a gradient-mixing injection device consisting of a controller and injection pumps is design. Bioactive glass (BG) and gellan gum (GG) are used to prepare thermosensitive injectable gradient hydrogels (B0.5 G, B1 G) with an upper critical solution temperature (UCST) range of 37.7-40.2 °C using this device for the first time. The mechanical properties of gradient hydrogels are significantly better than those of pure GG hydrogels. The gradients in the composition, structure, and morphology of gradient hydrogels are confirmed via physicochemical characterization. Cytocompatibility tests show that hydrogels, especially B0.5 G gradient hydrogels, promote the proliferation of bone marrow mesenchymal stem cells (BMSCs). Most importantly, qRT-PCR shows that the different components in B0.5 G gradient hydrogels simultaneously induce the osteogenic and chondrogenic differentiation of BMSCs. Experimental injection in porcine osteochondral defects indicates that the B0.5 G gradient hydrogel seamlessly fills irregular osteochondral defects in a less invasive manner by controlling the temperature to avoid cellular and tissue damage arising from crosslinkers or other conditions. These results show that thermosensitive injectable B0.5 G gradient hydrogels have the potential for less invasive integrated osteochondral repair.
Hydrogels , Mesenchymal Stem Cells , Animals , Swine , Hydrogels/pharmacology , Hydrogels/chemistry , Quality of Life , Cell Differentiation , Osteogenesis
Chimera states in nonidentical oscillators have received extensive attention in recent years. Previous studies have demonstrated that chimera states can exist in a ring of nonlocally coupled bicomponent oscillators even in the presence of strong parameter heterogeneity. In this study, we investigate spiral wave chimeras in two-dimensional nonlocally coupled bicomponent oscillators where oscillators are randomly divided into two groups, with identical oscillators in the same group. Using phase oscillators and FitzHugh-Nagumo oscillators as examples, we numerically demonstrate that each group of oscillators supports its own spiral wave chimera and two spiral wave chimeras coexist with each other. We find that there exist three heterogeneity regimes: the synchronous regime at weak heterogeneity, the asynchronous regime at strong heterogeneity, and the transition regime in between. In the synchronous regime, spiral wave chimeras supported by different groups are synchronized with each other by sharing a same rotating frequency and a same incoherent core. In the asynchronous regime, the two spiral wave chimeras rotate at different frequencies and their incoherent cores are far away from each other. These phenomena are also observed in a nonrandom distribution of the two group oscillators and the continuum limit of infinitely many phase oscillators. The transition from synchronous to asynchronous spiral wave chimeras depends on the component oscillators. Specifically, it is a discontinuous transition for phase oscillators but a continuous one for FitzHugh-Nagumo oscillators. We also find that, in the asynchronous regime, increasing heterogeneity leads irregularly meandering spiral wave chimeras to rigidly rotating ones.
Chimera states refer to the dynamical states in which the inherent symmetry of the system is broken. The system composed of two interacting identical subpopulations of phase oscillators provides a platform to study chimera states. In this system, different types of chimera states have been identified and the transitions between them have been investigated. However, the parameter space is not fully explored in this system. In this work, we study a system comprised of two interacting subpopulations of nonidentical phase oscillators. Through numerical simulations and theoretical analyses, we find three symmetry-reserving states, including incoherent state, in-phase synchronous state, and antiphase synchronous state, and three types of symmetry-breaking states, including in-phase chimera states, antiphase chimera states, and weak chimera states. The stability diagrams of these dynamical states are explored on different parameter planes and transition scenarios amongst these states are investigated. We find that the weak chimera states act as the bridge between in-phase and antiphase chimera states. We also observe the existence of a period-two chimera state, chaotic chimera state, and drifting chimera states.
In this work, we study the Sakaguchi-Kuramoto model with natural frequency following a bimodal distribution. By using Ott-Antonsen ansatz, we reduce the globally coupled phase oscillators to low dimensional coupled ordinary differential equations. For symmetrical bimodal frequency distribution, we analyze the stabilities of the incoherent state and different partial synchronous states. Different types of bifurcations are identified and the effect of the phase lag on the dynamics is investigated. For asymmetrical bimodal frequency distribution, we observe the revival of the incoherent state, and then the conditions for the revival are specified.
Biological Clocks , Models, Statistical , Animals , Biological Clocks/physiology
The future of manufacturing applications in three-dimensional (3D) printing depends on the improvement and the development of materials suitable for 3D printing technology. This study aims to develop an applicable and convenient protocol for light-curing resin used in 3D industry, which could enhance antibacterial and mechanical properties of polymethyl methacrylate (PMMA) resin through the combination of nano-fillers of surface modified titanium dioxide (TiO2) and micro-fillers of polyetheretherketone (PEEK). PMMA-based composite resins with various additions of TiO2 and PEEK were prepared and submitted to characterizations including mechanical properties, distribution of the fillers (TiO2 or/and PEEK) on the fractured surface, cytotoxicity, antibacterial activity, and blood compatibility assessment. These results indicated that the reinforced composite resins of PMMA (TiO2-1%-PEEK-1%) possessed the most optimized properties compared to the other groups. In addition, we found the addition of 1% of TiO2 would be an effective amount to enhance both mechanical and antibacterial properties for PMMA composite resin. Furthermore, the model printed by PMMA (TiO2-1%-PEEK-1%) composite resin showed a smooth surface and a precise resolution, indicating this functional dental restoration material would be a suitable light-curing resin in 3D industry.
In globally coupled phase oscillators, the distribution of natural frequency has strong effects on both synchronization transition and synchronous dynamics. In this work, we study a ring of nonlocally coupled phase oscillators with the frequency distribution made up of two Lorentzians with the same center frequency but with different half widths. Using the Ott-Antonsen ansatz, we derive a reduced model in the continuum limit. Based on the reduced model, we analyze the stability of the incoherent state and find the existence of multiple stability islands for the incoherent state depending on the parameters. Furthermore, we numerically simulate the reduced model and find a large number of twisted states resulting from the instabilities of the incoherent state with respect to different spatial modes. For some winding numbers, the stability region of the corresponding twisted state consists of two disjoint parameter regions, one for the intermediate coupling strength and the other for the strong coupling strength.
Models, Theoretical , Nonlinear Dynamics
With the rapid application of light-curing 3D printing technology, the demand for high-performance polymer resins is increasing. Existing light-curable resins often have drawbacks limiting their clinical applications. This study aims to develop a new type of polymethyl methacrylate (PMMA) composite resins with enhanced mechanical properties, high antibacterial activities and excellent biocompatibilities. A series of reinforced composite resins were prepared by mechanically mixing PMMA with modified cellulose nanocrystals (CNCs), which were coated with polydopamine and decorated by silver nanoparticles (AgNPs) via Tollen reaction. The morphology of CNCs-Ag was observed by transmission electron microscopy and the formation of AgNPs on CNCs was confirmed by X-Ray photoelectron spectroscopy analyses. Functional groups in PMMA-CNCs-Ag composites were verified by Fourier Transform infrared spectroscopy (FTIR) spectroscopy. The mechanical assessment and scanning electron microscopy analysis suggested that the evenly distributed CNCs-AgNPs composite effectively improve mechanical properties of PMMA resin. Cytotoxicity assay and antibacterial activity tests indicated excellent biocompatibility and high antibacterial activities. Furthermore, PMMA with CNCs-AgNPs of 0.1 wt.% (PMMA-CNCs-AgNPs-0.1) possessed the most desirable mechanical properties owing to the homogeneous distribution of AgNPs throughout the resin matrix. This specific composite resin can be used as a functional dental restoration material with potential of other medical applications.
OBJECTIVE: To investigate the clinical effect of a new bundle-to-bundle suturing method for acute Achilles tendon rupture. METHODS: From April 2013 to January 2015, 15 patients with acute Achilles tendon rupture were treated with a new bundle-to-bundle suturing method including 12 males and 3 females with an average age of 37.5 years old ranging from 27 to 56 years old. All of them were immobilized by cast for 6 weeks on the underlying limbs, and were educated for a rehabilitation training during the follow-up. RESULTS: All the patients were followed up for 9 to 17.5 months with an average of 13.5 months. According to the American Ankle Surgery Association (AOFAS), ankle and foot score was 93.3±3.5 at 6 months after operation. All patients got incomplete weight-bearing at 1.6 months on average after the operation, and back to primary work position 4.7 months later on average. All the wounds got primary healing. No incisional infection, necrosis of incisional marginal necrosis, rupture of the Achilles tendon, and gastrocnemius injury occurred. CONCLUSIONS: The surgical treatment of acute Achilles tendon rupture with bundle-to-bundle suturing method has advantages of mini-invasion, a low rate of incision problems and quick function recovery, and was valuable spread in clinic.
Achilles Tendon/surgery , Rupture/surgery , Suture Techniques , Tendon Injuries/surgery , Achilles Tendon/injuries , Adult , Female , Humans , Male , Middle Aged , Treatment Outcome , Wound Healing
Chimera states, which consist of coexisting domains of spatially coherent and incoherent dynamics, have been intensively investigated in the past decade. In this work, we report a special chimera state, 2-frequency chimera state, in one-dimensional ring of nonlocally coupled Brusselators. In a 2-frequency chimera state, there exist two types of coherent domains and oscillators in different types of coherent domains have different mean phase velocities. We present the stability diagram of 2-frequency chimera state and study the transition between the 2-frequency chimera state and an ordinary 2-cluster chimera state.
Equipment Design , Models, Theoretical
In this work, we study the Kuramoto model with biharmonic interaction and bimodal frequency distribution. Rich synchronous dynamics, such as standing wave states, stationary partial synchronous dynamics, and multiplicity of singular synchronous dynamics, are found. Notably, we find a symmetry-breaking synchronous dynamics when the peaks in frequency distribution are not well separated. We present the phase diagrams for two cases: the peaks in the frequency distribution are well separated and the peaks are not well separated. We find that reducing peak distance tends to make the transition between standing wave states and stationary partial synchronous states to be continuous when the multiplicity of singular synchronous state is present or to be discontinuous when the multiplicity is absent.
We investigate a Deffuant model on a ring by introducing two modifications: the repelling mechanism and the circular opinions. The repelling mechanism drives the opinions of two individuals away from each other and the circular opinions are defined on a circle. We find that the repelling mechanism tends to polarize the opinions of adjacent individuals and the circular opinions bring up a spatiotemporal pattern in which all individuals take different opinions but the opinion difference between two neighboring individuals tends to zero in the limit of the population size. In the Deffuant model with both repelling mechanism and the circular opinions, opinion dynamics depends on both the bounded confidence and the convergence rate. The interplay between the repelling mechanism and the circular opinion may give rise to time-dependent opinion dynamics.
We investigate the generalized Kuramoto model of globally coupled oscillators with inertia, in which oscillators with positive coupling strength are conformists and oscillators with negative coupling strength are contrarians. We consider the correlation between the coupling strengths of oscillators and the distributions of natural frequencies. Two different types of correlations are studied. It is shown that the model supports multistable synchronized states such as different types of travelling wave states, π state and another type of nonstationary state: an oscillating π state. The phase distribution oscillates in a confined region and the phase difference between conformists and contrarians oscillates around π periodically in the oscillating π state. The different types of travelling wave state may be characterized by the speed of travelling wave and the effective frequencies of oscillators. Finally, the bifurcation diagrams of the model in the parameter space are presented.
OBJECTIVE: To study clinical curative effects of a Masquelet technology in the treatment of gouty arthritis in the first metatarsophalangeal joint. METHODS: From February 2012 to May 2016, 7 patients with the gouth arthritis of the first metatarsophalangeal joint were treated by the Masqueket technology. There were 5 males and 2 females, ranging in age from 42 to 58 years old, with an average age of 50 years old. During the regular follow up, the bone healing was assessed by the radiographic imaging, and the orthopaedic foot and ankle Association (AOFAS) ankle function scoring system was used for comprehensive evaluation. RESULTS: All the patients were followed up, and the duration ranged from 6 to 8 months, with a mean of 7 months. All the wounds obtained first intention healing, and there were no complications such as wound infection, flap necrosis and other soft tissue complications. The time to bone healing was 3 to 4 months, with an average of 3.6 months. The AOFAS score was increased from preoperative 42.5±4.6 to postoperative 85.0±10.5. CONCLUSIONS: The application of Masquelet technique in the treatment of first metatarsophalangeal joint gouty arthritis achieves obvious symptom relief, has less complications, and can effectively improve the quality of life of patients, which is a new and effective treatment.
Arthritis, Gouty/surgery , Metatarsophalangeal Joint/surgery , Adult , Arthrodesis/methods , Female , Follow-Up Studies , Humans , Male , Middle Aged , Quality of Life , Treatment Outcome
The prisoner's dilemma (PD), in which players can either cooperate or defect, is considered a paradigm for studying the evolution of cooperation in spatially structured populations. There the compact cooperator cluster is identified as a characteristic pattern and the probability of forming such pattern in turn depends on the features of the networks. In this paper, we investigate the influence of expansion of neighborhood on pattern formation by taking a weak PD game with one free parameter T, the temptation to defect. Two different expansion methods of neighborhood are considered. One is based on a square lattice and expanses along four directions generating networks with degree increasing with K=4m. The other is based on a lattice with Moore neighborhood and expanses along eight directions, generating networks with degree of K=8m. Individuals are placed on the nodes of the networks, interact with their neighbors and learn from the better one. We find that cooperator can survive for a broad degree 4≤K≤70 by taking a loose type of cooperator clusters. The former simple corresponding relationship between macroscopic patterns and the microscopic PD interactions is broken. Under a condition that is unfavorable for cooperators such as large T and K, systems prefer to evolve to a loose type of cooperator clusters to support cooperation. However, compared to the well-known compact pattern, it is a suboptimal strategy because it cannot help cooperators dominating the population and always corresponding to a low cooperation level.
The model of nonlocally coupled identical phase oscillators on complex networks is investigated. We find the existence of chimera states in which identical oscillators evolve into distinct coherent and incoherent groups. We find that the coherent group of chimera states always contains the same oscillators no matter what the initial conditions are. The properties of chimera states and their dependence on parameters are investigated on both scale-free networks and Erdös-Rényi networks.
The dynamics in a variant of globally coupled Sakaguchi-Kuramoto [corrected]. phase oscillators is studied. The model consists of two subpopulations, each with a different phase lag and interaction strength. Using Ott-Antonson ansatz, we analyze the dynamics in the model and present the numerical results. There exist stationary synchronous states which are generalized π states and two types of traveling wave states. We find that the traveling wave states are the dominant dynamics in comparison with the stationary states. Particularly, we find that the stationary and traveling wave states can be smoothly connected through the properly chosen parameter paths.
Nonlinear Dynamics , Motion , Probability
