Lithospheric structure beneath the northeastern Qinghai-Xizang Plateau is of vital significance for studying the geodynamic processes of crustal thickening and expansion of the Qinghai-Xizang Plateau. We conducted a j...Lithospheric structure beneath the northeastern Qinghai-Xizang Plateau is of vital significance for studying the geodynamic processes of crustal thickening and expansion of the Qinghai-Xizang Plateau. We conducted a joint inversion of receiver functions and surface wave dispersions with P-wave velocity constraints using data from the Chin Array Ⅱ temporary stations deployed across the Qinghai-Xizang Plateau. Prior to joint inversion, we applied the H-κ-c method(Li JT et al., 2019) to the receiver function data in order to correct for the back-azimuthal variations in the arrival times of Ps phases and crustal multiples caused by crustal anisotropy and dipping interfaces. High-resolution images of vS, crustal thickness, and vP/vSstructures in the Qinghai-Xizang Plateau were simultaneously derived from the joint inversion. The seismic images reveal that crustal thickness decreases outward from the Qinghai-Xizang Plateau. The stable interiors of the Ordos and Alxa blocks exhibited higher velocities and lower crustal vP/vSratios. While, lower velocities and higher vP/vSratios were observed beneath the Qilian Orogen and Songpan-Ganzi terrane(SPGZ), which are geologically active and mechanically weak, especially in the mid-lower crust.Delamination or thermal erosion of the lithosphere triggered by hot asthenospheric flow contributes to the observed uppermost mantle low-velocity zones(LVZs) in the SPGZ. The crustal thickness, vS, and vP/vSratios suggest that whole lithospheric shortening is a plausible mechanism for crustal thickening in the Qinghai-Xizang Plateau, supporting the idea of coupled lithospheric-scale deformation in this region.展开更多
Collagen is the building component of temporomandibular joint(TMJ) discs and is often affected by inflammation in temporomandibular disorders. The macromechanical properties of collagen are deteriorated by chronic inf...Collagen is the building component of temporomandibular joint(TMJ) discs and is often affected by inflammation in temporomandibular disorders. The macromechanical properties of collagen are deteriorated by chronic inflammation. However,the mechanism by which inflammation influences disc function remains unknown. The relationship between the ultrastructure and nanomechanical properties of collagen in inflamed discs should be clarified. Seven-week-old female Sprague–Dawley rats were randomly divided into two groups. Chronic TMJ inflammation was induced by intra-articular injection of complete Freund's adjuvant, and samples were harvested after 5 weeks. Picrosirius staining revealed multiple colours under polarized light, which represented alternative collagen bundles in inflamed discs. Using atomic force microscopy scanning, the magnitude of Young's modulus was reduced significantly accompanied with disordered collagen fibril arrangement with porous architecture of inflamed discs. Transmission electron microscopy scanning revealed a non-uniform distribution of collagen fibres, and oversized collagen fibrils were observed in inflamed discs. Fourier transform infrared microspectroscopy revealed a decrease in 1 338 cm^(-1)/amide II area ratio of collagen in different regions. The peak positions of amide I and amide II bands were altered in inflamed discs,indicating collagen unfolding. Our results suggest that sustained inflammation deteriorates collagen structures, resulting in the deterioration of the ultrastructure and nanomechanical properties of rat TMJ discs.展开更多
Objective: The aim of the study was to evaluate the effect of platelet rich growth factors (PRGFs) in treatment of temporomandibular joint disc displacement. Materials and Methods: The study subjects included 8 female...Objective: The aim of the study was to evaluate the effect of platelet rich growth factors (PRGFs) in treatment of temporomandibular joint disc displacement. Materials and Methods: The study subjects included 8 females having bilateral anterior disc displacement with reduction and 1 female having bilateral anterior disc displacement without reduction with the age range between 20 - 35 years. The process of obtaining PRGFs was carried out following the Anitua Technique. Results: Clinical parameters of Interincisal distance, Lateral excursion of mandible using digital caliper in millimeters and Visual Analogue Scale (VAS 0/10) for pain intensity score were used. All of these parameters were running through the intervals of two, four, and eight weeks till the end of the follow-up period at twenty-six weeks (six months). The participated patients showed the clinical improvement in the different clinical statuses such as interincisal distance;lateral excursion of mandible and Pain Score. Conclusion: the study reported early efficacy of PRGFs after the arthrocentesis of the joint in treatment of TMJ disc displacement, and according to our results, the injection of PRGFs could be a possible alternative treatment for patients who did not respond to standard treatment.展开更多
Resonance effects in parallel jointed rocks subject to stress waves are investigated using transfer functions,derived from signals generated through numerical modelling.Resonance is important for a range of engineerin...Resonance effects in parallel jointed rocks subject to stress waves are investigated using transfer functions,derived from signals generated through numerical modelling.Resonance is important for a range of engineering situations as it identifies the frequency of waves which will be favourably transmitted.Two different numerical methods are used for this study,adopting the finite difference method and the combined discrete element-finite difference method.The numerical models are validated by replicating results from previous studies.The two methods are found to behave similarly and show the same resonance effects;one operating at low frequency and the other operating at relatively high frequency.These resonance effects are interpreted in terms of simple physical systems and analytical equations are derived to predict the resonant frequencies of complex rock masses.Low frequency resonance is shown to be generated by a system synonymous with masses between springs,described as spring resonance,with an equal number of resonant frequencies as the number of blocks.High frequency resonance is generated through superposition of multiple reflected waves developing standing waves within intact blocks,described as superposition resonance.While resonance through superposition has previously been identified,resonance based on masses between springs has not been previously identified in jointed rocks.The findings of this study have implications for future analysis of multiple jointed rock masses,showing that a wave travelling through such materials can induce other modes of propagation of waves,i.e.spring resonance.展开更多
The purpose of the study was designed to clarify the modern trends of physical therapy in treatment of temporomandibular joint dysfunctions in Parkinsonian patients, which in this respect included the degree of pain, ...The purpose of the study was designed to clarify the modern trends of physical therapy in treatment of temporomandibular joint dysfunctions in Parkinsonian patients, which in this respect included the degree of pain, the muscles power of both masseter and pterygoid, the range of TMJ motion, the angle of mouth opening and their effects on electromyography study in both sexes. Subjects: Thirty males and females were the same degree of disabilities according to modified Hoehn and Yahr scales (grade 3) of Parkinsonian patients, and their age ranged from 50 - 77 years old and their weight ranged from 60 - 88 kg. They were randomly divided into two equal groups (G1 and G2). G1 (control) consisted of 15 patients of both sexes and was treated by exercises therapy program and G2 (experimental) consisted of 15 Parkinsonian patients of both sexes and was treated by the same exercises therapy program and low level pulsed electromagnetic therapy. Vital signs such as blood pressure, body temperature, pulse rate and respiratory rate were measured before and after the treatment sessions. Assessments: Visual analogue scale was used to measure degree of pain. Tensiometer was used to measure the muscle power of masseter and pterygoid, the digital goniometer was used to investigate the range of TMJ movement. Moreover, standard electromyography test (EMG) was used to measure the compound muscle action potentials. Statistically the results for all groups were analyzed by t-test to compare the differences between the two groups. The statistical package of social sciences (SPSS, version 10) was used for data processing using the P-value 0.05 as a level of significance. Results showed that there were significant improvements in all variables in G2 only. However, there was a little improvement but not significant in both G1. Therefore, it could be concluded that the use of low level pulsed electro-magnetic therapy combined with exercises program was the good method to control pain of TMJ, increase of muscle power and the range of their movements together with determination of electro-myography. Our results opened a new link to manage the TMJ dysfunctions in Parkinsonian patients via the use of low level pulsed electromagnetic therapy combined with exercises program.展开更多
Objective To investigate the effect of orthodontic therapy on disorder syndrome of temporomandibular joint. Method Perform orthodontic therapy on 37 patients with disorder syndrome of temporomandibular joints. Result ...Objective To investigate the effect of orthodontic therapy on disorder syndrome of temporomandibular joint. Method Perform orthodontic therapy on 37 patients with disorder syndrome of temporomandibular joints. Result 26 patients healed, 9 became better, in whom the healing rate of adults was lower. Conclusion Comprehensive therapy is needed in patients with disorder syndrome of temporomandibular joint and the balance and stability should be emphasized after orthodontic therapy.展开更多
Objective:To study the effect of repetitive peripheral magnetic stimulation(rPMS)combined with conventional rehabilitation measures on shoulder dysfunction in early stroke.Methods:60 patients with shoulder dysfunction...Objective:To study the effect of repetitive peripheral magnetic stimulation(rPMS)combined with conventional rehabilitation measures on shoulder dysfunction in early stroke.Methods:60 patients with shoulder dysfunction in early stroke were selected,and all of them were admitted to our hospital from August 2021 to August 2023.The patients were randomly grouped into a control group(conventional rehabilitation measures intervention,30 cases)and an intervention group(rPMS and conventional rehabilitation measures intervention,30 cases)according to the lottery method.The pain scores,shoulder mobility,and motor function scores of the two groups were compared.Results:The pain score was lower in the intervention group,and the shoulder mobility and motor function scores were higher in the intervention group(P<0.05)as compared to that of the control group.Conclusion:The effect of combining rPMS and conventional rehabilitation measures in treating shoulder dysfunction in early stroke was remarkable and should be popularized.展开更多
The objectives of this study were to(1) determine the distribution and synthesis of pericellular matrix(PCM) molecules(collagen VI, collagen IV and laminin) in rat temporomandibular joint(TMJ) and(2) investigate the e...The objectives of this study were to(1) determine the distribution and synthesis of pericellular matrix(PCM) molecules(collagen VI, collagen IV and laminin) in rat temporomandibular joint(TMJ) and(2) investigate the effects of PCM molecules on chondrocytes against inflammation in osteoarthritis. Four zones(fibrous, proliferating, mature and hypertrophic) of condylar cartilage and three bands(anterior, intermediate and posterior) of disc were analysed by immunohistochemistry for the presence of PCM molecules in rat TMJs. Isolated chondrocytes were pre-treated with PCM molecules before being subjected to interleukin(IL)-1β treatment to stimulate inflammation. The responses of the chondrocytes were analysed using gene expression, nitric oxide release and matrix metalloproteinase(MMP)-13 production measures. Histomorphometric analyses revealed that the highest areal deposition of collagen VI(67.4%), collagen IV(45.7%) and laminin(52.4%) was in the proliferating zone of TMJ condylar cartilage. No significant difference in the distribution of PCM molecules was noted among the three bands of the TMJ disc. All three PCM molecules were expressed intracellularly by chondrocytes cultured in the monolayer. Among the PCM molecules, pre-treatment with collagen VI enhanced cellular proliferation, ameliorated IL-1β-induced MMP-3, MMP-9, MMP-13 and inducible nitric oxide synthase gene expression, and attenuated the downregulation of cartilage matrix genes, including collagen I, aggrecan and cartilage oligomeric matrix protein(COMP). Concurrently, collagen VI pretreatment inhibited nitric oxide and MMP-13 production. Our study demonstrates for the first time the distribution and role of PCM molecules, particularly collagen VI, in the protection of chondrocytes against inflammation.展开更多
Imaging of the temporomandibular joint(TMJ) is continuously evolving with advancement of imaging technologies. Many different imaging modalities are currently used to evaluate the TMJ. Magnetic resonance imaging is co...Imaging of the temporomandibular joint(TMJ) is continuously evolving with advancement of imaging technologies. Many different imaging modalities are currently used to evaluate the TMJ. Magnetic resonance imaging is commonly used for evaluation of the TMJ due to its superior contrast resolution and its ability to acquire dynamic imaging for demonstration of the functionality of the joint. Computed tomography and ultrasound imaging have specific indication in imaging of the TMJ. This article focuses on state of the art imaging of the temporomandibular joint. Relevant normal anatomy and biomechanics of movement of the TMJ are discussed for better understanding of many TMJ pathologies. Imaging of internal derangements is discussed in detail. Different arthropathies and commontumors are also discussed in this article.展开更多
AIM To establish minimum clinically important difference(MCID) for measurements in an orthopaedic patient population with joint disorders.METHODS Adult patients aged 18 years and older seeking care for joint condition...AIM To establish minimum clinically important difference(MCID) for measurements in an orthopaedic patient population with joint disorders.METHODS Adult patients aged 18 years and older seeking care for joint conditions at an orthopaedic clinic took the Patient-Reported Outcomes Measurement Information System Physical Function(PROMIS~? PF) computerized adaptive test(CAT), hip disability and osteoarthritis outcome score for joint reconstruction(HOOS JR), and the knee injury and osteoarthritis outcome score for joint reconstruction(KOOS JR) from February 2014 to April 2017. MCIDs were calculated using anchorbased and distribution-based methods. Patient reports of meaningful change in function since their first clinic encounter were used as an anchor.RESULTS There were 2226 patients who participated with a mean age of 61.16(SD = 12.84) years, 41.6% male, and 89.7% Caucasian. Mean change ranged from 7.29 to 8.41 for the PROMIS~? PF CAT, from 14.81 to 19.68 for the HOOS JR, and from 14.51 to 18.85 for the KOOS JR. ROC cut-offs ranged from 1.97-8.18 for the PF CAT, 6.33-43.36 for the HOOS JR, and 2.21-8.16 for the KOOS JR. Distribution-based methods estimated MCID values ranging from 2.45 to 21.55 for the PROMIS~? PF CAT; from 3.90 to 43.61 for the HOOS JR, and from 3.98 to 40.67 for the KOOS JR. The median MCID value in the range was similar to the mean change score for each measure and was 7.9 for the PF CAT, 18.0 for the HOOS JR, and 15.1 for the KOOS JR.CONCLUSION This is the first comprehensive study providing a wide range of MCIDs for the PROMIS? PF, HOOS JR, and KOOS JR in orthopaedic patients with joint ailments.展开更多
Highly deformable bodies are essential for numerous types of applications in all sorts of environments. Joint-like structures comprising a ball and socket joint have many degrees of freedom that allow mobility of many...Highly deformable bodies are essential for numerous types of applications in all sorts of environments. Joint-like structures comprising a ball and socket joint have many degrees of freedom that allow mobility of many biomimetic structures. Recently, soft robots are favored over rigid structures for their highly compliant material, high-deformation properties at low forces, and ability to operate in di fficult environments. However, it is still challenging to fabricate complex designs that satisfy application constraints due to the combined e ffects of material properties, actuation method, and structural geometry on the performance of the soft robot. Therefore, a combination of a rigid joint and a soft body can help achieve modular robots with fully functional body morphology. Yet, the fabrication of soft parts requires extensive molding for complex shapes, which comprises several processes and can be time-consuming. In addition, molded connections between extremely soft materials and hard materials can be critical failing points. In this paper, we present a functionally graded 3D-printed joint-like structure actuated by novel contractile actuators. Functionally graded materials (FGMs) via 3D printing allow for extensive material property enhancement and control which warrant tunable functionalities of the system. The 3D-printed structure is made of 3 rigid ball and socket joints connected in series and actuated by integrating twisted and coiled polymer fishing line ( TCPFL) actuators, which are con fined in the FGM accordion-shaped channels. The implementation of the untethered T CPFL actuation system can be highly bene ficial for deployment in environments that require low vibrations and silent actuation. The fishing line TCP actuators produce an actuation strain up to 40% and bend the joint up to 40° in any direction. The T CPFL can be actuated individually or as a group to control the bending trajectory of the modular joint, which is bene ficial when deployed in areas that contain small crevices. Obtaining complex modes of bending, the FGM multidirectional joint demonstrated a great potential to achieve di fferent functionalities such as crawling, rolling, swimming, or underwater exploration.展开更多
A finite element model of the temporomandibular joint(TMJ)and the human mandible was fabricated to study the effect of abnormal loading,such as awake and asleep bruxism,on the articular disc.A quasilinear viscoelastic...A finite element model of the temporomandibular joint(TMJ)and the human mandible was fabricated to study the effect of abnormal loading,such as awake and asleep bruxism,on the articular disc.A quasilinear viscoelastic model was used to simulate the behaviour of the disc.The viscoelastic nature of this tissue is shown to be an important factor when sustained(awake bruxism)or cyclic loading(sleep bruxism)is simulated.From the comparison of the two types of bruxism,it was seen that sustained clenching is the most detrimental activity for the TMJ disc,producing an overload that could lead to severe damage of this tissue.展开更多
Septic arthritis of the temporomandibular joint (TMJ) is a rare disease that is characterized by preauricular pain, edema, malocclusion, trismus and abscess formation in the TMJ region. An 85-year-old male visited our...Septic arthritis of the temporomandibular joint (TMJ) is a rare disease that is characterized by preauricular pain, edema, malocclusion, trismus and abscess formation in the TMJ region. An 85-year-old male visited our hospital with the complaint of left-sided TMJ swelling, pain and trismus. Septic arthritis of the left TMJ was diagnosed on the basis of considerable elevation of CRP (Creactive proteins) and CT imaging findings. The patient was treated with oral Faropenem at 450 mg daily, but CRP increased three days after the initial visit. He was hospitalized and treated with intravenous administration of cefazolin at 2 g and clindamycin at 1.2 g daily for six days. Propionibacterium species and Veillonella species grew in a culture of the joint aspirate, but there was no apparent source of infection. After acute infectious symptoms had passed, the patient was treated with oral amoxicillin at 750 mg daily for eight weeks and was instructed to do jaw opening exercise. The patient was discharged on the 11th hospital day. After three weeks of the hospital discharge, the patient healed completely. To avoid serious complications, clinicians should include septic arthritis of the TMJ in the differential diagnosis of preauricular pain, trismus and swelling.展开更多
Treatment of bone tumors in the mandible often involves extensive excavation of affected bone, followed by mandibular reconstruction. Prosthetic implants may be needed to restore jaw functionality. The challenges of m...Treatment of bone tumors in the mandible often involves extensive excavation of affected bone, followed by mandibular reconstruction. Prosthetic implants may be needed to restore jaw functionality. The challenges of making prosthetic bone implants include stress shielding and extending the mechanical life of the implant. We have developed a design algorithm to improve the efficiency of prosthesis design. A finite element model of the patient case is constructed from a computer tomography scan, and the computer implements topology optimization techniques to design the prosthesis with limited stress shielding affected by highly biomechanical compatibility. Topology optimization facilitates the design of low weight structures by automatically introducing holes into the structure. This is governed by engineering predetermined constraints to meet certain job specifications. Such a design will be tested for fatigue life before it is ready to be manufactured and used. Topology optimization can be performed as a design process to achieve a final design that takes stress shielding into consideration. The problem of stress shielding is solved by matching the stiffness of the orthopedic implant to the original bone that is being replaced. The material we used was titanium alloy (Ti-6Al-7Nb). Volume fraction of the orthodox implant was used (0.2872 for the studied case) as volume constraints. Compliance of the bulk bone was set as a further constraint to match the stiffness of the bone with the designed structure. Our results show a good life expectancy for the designed parts, with 12% higher life expectancy for stress-based topology optimization than for compliance-based topology optimization.展开更多
BACKGROUND The role of occlusal factors on the occurrence of temporomandibular joint disorders(TMDs)is still unclear and it is tricky for orthodontists to treat malocclusions in patients with TMDs.We report the case o...BACKGROUND The role of occlusal factors on the occurrence of temporomandibular joint disorders(TMDs)is still unclear and it is tricky for orthodontists to treat malocclusions in patients with TMDs.We report the case of the second orthodontic treatment of an adult female with Class II division 2 malocclusion associated with TMD.With the removal of anterior occlusal interference,TMD symptoms were alleviated and cone beam computed tomography(CBCT)images showed the bilateral condyles shifted forward.CASE SUMMARY This case report presented an orthodontic retreatment of an adult female with TMD and mandibular backward positioning based on CBCT examination and Joint Space Index(JSI)analysis.The left and right JSI values of-38.5 and-52.6 indicated that the position of bilateral condyles had posterior displacement.Ten years prior to this evaluation,she underwent orthodontic treatment resulting in the extraction of two upper premolars and one lower central incisor.The joint symptoms,including pain and sounds,were alleviated along with verified mandibular forward repositioning by extraction of another lower central incisor.CONCLUSION Mandibular backward positioning could be associated with TMD.JSI analysis based on CBCT is a convenient way to examine condylar positions quantitatively.展开更多
BACKGROUND Condylar osteophytes,a remodeling form of temporomandibular joint osteoarthritis(TMJ OA),mainly manifest as marginal angular outgrowths of the condyle.Previous researchers have advocated surgical removal of...BACKGROUND Condylar osteophytes,a remodeling form of temporomandibular joint osteoarthritis(TMJ OA),mainly manifest as marginal angular outgrowths of the condyle.Previous researchers have advocated surgical removal of condylar osteophytes.Reports on the effect of occlusal splint on TMJ OA patients’joints have mostly focused on treatment with this splint,which can reduce the absorption of the affected condyle and promote repair and regeneration.However,the effect of the splint on the dissolution of condylar osteophytes has not yet been reported.CASE SUMMARY A 68-year-old female patient suffered from occlusal discomfort with left facial pain for 2 years.Cone beam computed tomography showed a rare osteophyte on top of her left condyle.She was finally diagnosed with TMJ OA.The patient refused surgical treatment and received conservative treatment with a muscle balance occlusal splint.The pain experienced by the patient on the left side of her face was relieved,and her chewing ability recovered after treatment.The osteophyte dissolved,and the condylar cortex remained stable during long-term follow-up observations.CONCLUSION The muscle balance occlusal splint could be a noninvasive means of treating condylar osteophytes in TMJ OA patients.展开更多
This article reviews the imaging anatomy of temporomandibular joint(TMJ), describes the technique of multi-detector computed tomography(MDCT) of the TMJ, and describes in detail various osseous pathologic afflictions ...This article reviews the imaging anatomy of temporomandibular joint(TMJ), describes the technique of multi-detector computed tomography(MDCT) of the TMJ, and describes in detail various osseous pathologic afflictions affecting the joint. Traumatic injuries affecting the mandibular condyle are most common, followed by joint ankylosis as a sequel to arthritis. The congenital anomalies are less frequent, hemifacial microsomia being the most commonly encountered anomaly involving the TMJ. Neoplastic afflictions of TMJ are distinctly uncommon, osteochondroma being one of the most common lesions. MDCT enables comprehensive evaluation of osseous afflictions of TMJ, and is a valuable tool for surgical planning. Sagittal, coronal and 3D reformatted images well depict osseous TMJ lesions, and their relationship to adjacent structures.展开更多
Background: Pigmented villonodular synovitis is a rare condition typically affecting the major joints and the involvement of the temporomandibular joint is rare. Although, it is histologically benign, it can be locall...Background: Pigmented villonodular synovitis is a rare condition typically affecting the major joints and the involvement of the temporomandibular joint is rare. Although, it is histologically benign, it can be locally aggressive, capable of extensive bone destruction. The disease has aggressive behavior and a high incidence of recurrence (40% - 60%). Case report: A 35 years old male presented with history of unilateral hearing loss and otalgia of six month duration. On examination, there was a soft bulge in the superior wall of external auditory canal. Contrast enhanced CT scan showed soft tissue density occupying the right external auditory canal and bulging into the middle ear cavity, displacing the intact ossicular chain medially with evidence of destruction of the posterior wall of the external auditory canal, glenoid fossa, mastoid bone and the scutum. The squamous part of the right temporal bone showed evidence of lateral bowing with discontinuity. Surgical resection was done through post aural approach. Histopathological examination revealed pigmented villonodular tenosynovitis which stained positive for CD 68. Post operatively patient was evaluated clinically and with radiological modalities which showed healthy mastoid cavity and no increase in post operative granulations on magnetic resonance imaging. Conclusion: Pigmented villonodular tenosynovitis of temporomandibular joint is a rare entity. Due to the aggressive behavior of the lesion, radical or aggressive surgical resection should be done. Long term follow up with radiological modality should be done due to the high recurrence rate.展开更多
Accurate determination of seismic velocity of the crust is important for understanding regional tectonics and crustal evolution of the Earth. We propose a stepwise joint linearized inversion method using surface wave ...Accurate determination of seismic velocity of the crust is important for understanding regional tectonics and crustal evolution of the Earth. We propose a stepwise joint linearized inversion method using surface wave dispersion, Rayleigh wave ZH ratio(i.e., ellipticity), and receiver function data to better resolve 1D crustal shear wave velocity(v_S) structure. Surface wave dispersion and Rayleigh wave ZH ratio data are more sensitive to absolute variations of shear wave speed at depths, but their sensitivity kernels to shear wave speeds are different and complimentary. However, receiver function data are more sensitive to sharp velocity contrast(e.g., due to the existence of crustal interfaces) and v_P/v_S ratios. The stepwise inversion method takes advantages of the complementary sensitivities of each dataset to better constrain the v_S model in the crust. We firstly invert surface wave dispersion and ZH ratio data to obtain a 1D smooth absolute v_S model and then incorporate receiver function data in the joint inversion to obtain a finer v_S model with better constraints on interface structures. Through synthetic tests, Monte Carlo error analyses, and application to real data, we demonstrate that the proposed joint inversion method can resolve robust crustal v_S structures and with little initial model dependency.展开更多
基金supported by the Natural Science Basic Research Program of Shaanxi(No.2023-JC-QN-0306)the Special Fund of the Institute of Geophysics,China Earthquake Administration(No.DQJB21B32)the National Natural Science Foundation of China(No.42174069).
文摘Lithospheric structure beneath the northeastern Qinghai-Xizang Plateau is of vital significance for studying the geodynamic processes of crustal thickening and expansion of the Qinghai-Xizang Plateau. We conducted a joint inversion of receiver functions and surface wave dispersions with P-wave velocity constraints using data from the Chin Array Ⅱ temporary stations deployed across the Qinghai-Xizang Plateau. Prior to joint inversion, we applied the H-κ-c method(Li JT et al., 2019) to the receiver function data in order to correct for the back-azimuthal variations in the arrival times of Ps phases and crustal multiples caused by crustal anisotropy and dipping interfaces. High-resolution images of vS, crustal thickness, and vP/vSstructures in the Qinghai-Xizang Plateau were simultaneously derived from the joint inversion. The seismic images reveal that crustal thickness decreases outward from the Qinghai-Xizang Plateau. The stable interiors of the Ordos and Alxa blocks exhibited higher velocities and lower crustal vP/vSratios. While, lower velocities and higher vP/vSratios were observed beneath the Qilian Orogen and Songpan-Ganzi terrane(SPGZ), which are geologically active and mechanically weak, especially in the mid-lower crust.Delamination or thermal erosion of the lithosphere triggered by hot asthenospheric flow contributes to the observed uppermost mantle low-velocity zones(LVZs) in the SPGZ. The crustal thickness, vS, and vP/vSratios suggest that whole lithospheric shortening is a plausible mechanism for crustal thickening in the Qinghai-Xizang Plateau, supporting the idea of coupled lithospheric-scale deformation in this region.
基金supported by the National Natural Science Foundation of China (Grant Nos. 81671015, 81571815, 81470717)Beijing Municipal Science and Technology Commission (Grant No. Z171100001017128)
文摘Collagen is the building component of temporomandibular joint(TMJ) discs and is often affected by inflammation in temporomandibular disorders. The macromechanical properties of collagen are deteriorated by chronic inflammation. However,the mechanism by which inflammation influences disc function remains unknown. The relationship between the ultrastructure and nanomechanical properties of collagen in inflamed discs should be clarified. Seven-week-old female Sprague–Dawley rats were randomly divided into two groups. Chronic TMJ inflammation was induced by intra-articular injection of complete Freund's adjuvant, and samples were harvested after 5 weeks. Picrosirius staining revealed multiple colours under polarized light, which represented alternative collagen bundles in inflamed discs. Using atomic force microscopy scanning, the magnitude of Young's modulus was reduced significantly accompanied with disordered collagen fibril arrangement with porous architecture of inflamed discs. Transmission electron microscopy scanning revealed a non-uniform distribution of collagen fibres, and oversized collagen fibrils were observed in inflamed discs. Fourier transform infrared microspectroscopy revealed a decrease in 1 338 cm^(-1)/amide II area ratio of collagen in different regions. The peak positions of amide I and amide II bands were altered in inflamed discs,indicating collagen unfolding. Our results suggest that sustained inflammation deteriorates collagen structures, resulting in the deterioration of the ultrastructure and nanomechanical properties of rat TMJ discs.
文摘Objective: The aim of the study was to evaluate the effect of platelet rich growth factors (PRGFs) in treatment of temporomandibular joint disc displacement. Materials and Methods: The study subjects included 8 females having bilateral anterior disc displacement with reduction and 1 female having bilateral anterior disc displacement without reduction with the age range between 20 - 35 years. The process of obtaining PRGFs was carried out following the Anitua Technique. Results: Clinical parameters of Interincisal distance, Lateral excursion of mandible using digital caliper in millimeters and Visual Analogue Scale (VAS 0/10) for pain intensity score were used. All of these parameters were running through the intervals of two, four, and eight weeks till the end of the follow-up period at twenty-six weeks (six months). The participated patients showed the clinical improvement in the different clinical statuses such as interincisal distance;lateral excursion of mandible and Pain Score. Conclusion: the study reported early efficacy of PRGFs after the arthrocentesis of the joint in treatment of TMJ disc displacement, and according to our results, the injection of PRGFs could be a possible alternative treatment for patients who did not respond to standard treatment.
基金supported by the Engineering and Physical Sciences Research Council(EPSRC)(EP/R513258/1).
文摘Resonance effects in parallel jointed rocks subject to stress waves are investigated using transfer functions,derived from signals generated through numerical modelling.Resonance is important for a range of engineering situations as it identifies the frequency of waves which will be favourably transmitted.Two different numerical methods are used for this study,adopting the finite difference method and the combined discrete element-finite difference method.The numerical models are validated by replicating results from previous studies.The two methods are found to behave similarly and show the same resonance effects;one operating at low frequency and the other operating at relatively high frequency.These resonance effects are interpreted in terms of simple physical systems and analytical equations are derived to predict the resonant frequencies of complex rock masses.Low frequency resonance is shown to be generated by a system synonymous with masses between springs,described as spring resonance,with an equal number of resonant frequencies as the number of blocks.High frequency resonance is generated through superposition of multiple reflected waves developing standing waves within intact blocks,described as superposition resonance.While resonance through superposition has previously been identified,resonance based on masses between springs has not been previously identified in jointed rocks.The findings of this study have implications for future analysis of multiple jointed rock masses,showing that a wave travelling through such materials can induce other modes of propagation of waves,i.e.spring resonance.
文摘The purpose of the study was designed to clarify the modern trends of physical therapy in treatment of temporomandibular joint dysfunctions in Parkinsonian patients, which in this respect included the degree of pain, the muscles power of both masseter and pterygoid, the range of TMJ motion, the angle of mouth opening and their effects on electromyography study in both sexes. Subjects: Thirty males and females were the same degree of disabilities according to modified Hoehn and Yahr scales (grade 3) of Parkinsonian patients, and their age ranged from 50 - 77 years old and their weight ranged from 60 - 88 kg. They were randomly divided into two equal groups (G1 and G2). G1 (control) consisted of 15 patients of both sexes and was treated by exercises therapy program and G2 (experimental) consisted of 15 Parkinsonian patients of both sexes and was treated by the same exercises therapy program and low level pulsed electromagnetic therapy. Vital signs such as blood pressure, body temperature, pulse rate and respiratory rate were measured before and after the treatment sessions. Assessments: Visual analogue scale was used to measure degree of pain. Tensiometer was used to measure the muscle power of masseter and pterygoid, the digital goniometer was used to investigate the range of TMJ movement. Moreover, standard electromyography test (EMG) was used to measure the compound muscle action potentials. Statistically the results for all groups were analyzed by t-test to compare the differences between the two groups. The statistical package of social sciences (SPSS, version 10) was used for data processing using the P-value 0.05 as a level of significance. Results showed that there were significant improvements in all variables in G2 only. However, there was a little improvement but not significant in both G1. Therefore, it could be concluded that the use of low level pulsed electro-magnetic therapy combined with exercises program was the good method to control pain of TMJ, increase of muscle power and the range of their movements together with determination of electro-myography. Our results opened a new link to manage the TMJ dysfunctions in Parkinsonian patients via the use of low level pulsed electromagnetic therapy combined with exercises program.
文摘Objective To investigate the effect of orthodontic therapy on disorder syndrome of temporomandibular joint. Method Perform orthodontic therapy on 37 patients with disorder syndrome of temporomandibular joints. Result 26 patients healed, 9 became better, in whom the healing rate of adults was lower. Conclusion Comprehensive therapy is needed in patients with disorder syndrome of temporomandibular joint and the balance and stability should be emphasized after orthodontic therapy.
文摘Objective:To study the effect of repetitive peripheral magnetic stimulation(rPMS)combined with conventional rehabilitation measures on shoulder dysfunction in early stroke.Methods:60 patients with shoulder dysfunction in early stroke were selected,and all of them were admitted to our hospital from August 2021 to August 2023.The patients were randomly grouped into a control group(conventional rehabilitation measures intervention,30 cases)and an intervention group(rPMS and conventional rehabilitation measures intervention,30 cases)according to the lottery method.The pain scores,shoulder mobility,and motor function scores of the two groups were compared.Results:The pain score was lower in the intervention group,and the shoulder mobility and motor function scores were higher in the intervention group(P<0.05)as compared to that of the control group.Conclusion:The effect of combining rPMS and conventional rehabilitation measures in treating shoulder dysfunction in early stroke was remarkable and should be popularized.
基金supported by grants from the National University Healthcare System(R221000077733)the National University of Singapore(R221000090112)
文摘The objectives of this study were to(1) determine the distribution and synthesis of pericellular matrix(PCM) molecules(collagen VI, collagen IV and laminin) in rat temporomandibular joint(TMJ) and(2) investigate the effects of PCM molecules on chondrocytes against inflammation in osteoarthritis. Four zones(fibrous, proliferating, mature and hypertrophic) of condylar cartilage and three bands(anterior, intermediate and posterior) of disc were analysed by immunohistochemistry for the presence of PCM molecules in rat TMJs. Isolated chondrocytes were pre-treated with PCM molecules before being subjected to interleukin(IL)-1β treatment to stimulate inflammation. The responses of the chondrocytes were analysed using gene expression, nitric oxide release and matrix metalloproteinase(MMP)-13 production measures. Histomorphometric analyses revealed that the highest areal deposition of collagen VI(67.4%), collagen IV(45.7%) and laminin(52.4%) was in the proliferating zone of TMJ condylar cartilage. No significant difference in the distribution of PCM molecules was noted among the three bands of the TMJ disc. All three PCM molecules were expressed intracellularly by chondrocytes cultured in the monolayer. Among the PCM molecules, pre-treatment with collagen VI enhanced cellular proliferation, ameliorated IL-1β-induced MMP-3, MMP-9, MMP-13 and inducible nitric oxide synthase gene expression, and attenuated the downregulation of cartilage matrix genes, including collagen I, aggrecan and cartilage oligomeric matrix protein(COMP). Concurrently, collagen VI pretreatment inhibited nitric oxide and MMP-13 production. Our study demonstrates for the first time the distribution and role of PCM molecules, particularly collagen VI, in the protection of chondrocytes against inflammation.
文摘Imaging of the temporomandibular joint(TMJ) is continuously evolving with advancement of imaging technologies. Many different imaging modalities are currently used to evaluate the TMJ. Magnetic resonance imaging is commonly used for evaluation of the TMJ due to its superior contrast resolution and its ability to acquire dynamic imaging for demonstration of the functionality of the joint. Computed tomography and ultrasound imaging have specific indication in imaging of the TMJ. This article focuses on state of the art imaging of the temporomandibular joint. Relevant normal anatomy and biomechanics of movement of the TMJ are discussed for better understanding of many TMJ pathologies. Imaging of internal derangements is discussed in detail. Different arthropathies and commontumors are also discussed in this article.
基金National Institute of Arthritis and Musculoskeletal and Skin Diseases of the National Institutes of Health,No.U01AR067138.
文摘AIM To establish minimum clinically important difference(MCID) for measurements in an orthopaedic patient population with joint disorders.METHODS Adult patients aged 18 years and older seeking care for joint conditions at an orthopaedic clinic took the Patient-Reported Outcomes Measurement Information System Physical Function(PROMIS~? PF) computerized adaptive test(CAT), hip disability and osteoarthritis outcome score for joint reconstruction(HOOS JR), and the knee injury and osteoarthritis outcome score for joint reconstruction(KOOS JR) from February 2014 to April 2017. MCIDs were calculated using anchorbased and distribution-based methods. Patient reports of meaningful change in function since their first clinic encounter were used as an anchor.RESULTS There were 2226 patients who participated with a mean age of 61.16(SD = 12.84) years, 41.6% male, and 89.7% Caucasian. Mean change ranged from 7.29 to 8.41 for the PROMIS~? PF CAT, from 14.81 to 19.68 for the HOOS JR, and from 14.51 to 18.85 for the KOOS JR. ROC cut-offs ranged from 1.97-8.18 for the PF CAT, 6.33-43.36 for the HOOS JR, and 2.21-8.16 for the KOOS JR. Distribution-based methods estimated MCID values ranging from 2.45 to 21.55 for the PROMIS~? PF CAT; from 3.90 to 43.61 for the HOOS JR, and from 3.98 to 40.67 for the KOOS JR. The median MCID value in the range was similar to the mean change score for each measure and was 7.9 for the PF CAT, 18.0 for the HOOS JR, and 15.1 for the KOOS JR.CONCLUSION This is the first comprehensive study providing a wide range of MCIDs for the PROMIS? PF, HOOS JR, and KOOS JR in orthopaedic patients with joint ailments.
文摘Highly deformable bodies are essential for numerous types of applications in all sorts of environments. Joint-like structures comprising a ball and socket joint have many degrees of freedom that allow mobility of many biomimetic structures. Recently, soft robots are favored over rigid structures for their highly compliant material, high-deformation properties at low forces, and ability to operate in di fficult environments. However, it is still challenging to fabricate complex designs that satisfy application constraints due to the combined e ffects of material properties, actuation method, and structural geometry on the performance of the soft robot. Therefore, a combination of a rigid joint and a soft body can help achieve modular robots with fully functional body morphology. Yet, the fabrication of soft parts requires extensive molding for complex shapes, which comprises several processes and can be time-consuming. In addition, molded connections between extremely soft materials and hard materials can be critical failing points. In this paper, we present a functionally graded 3D-printed joint-like structure actuated by novel contractile actuators. Functionally graded materials (FGMs) via 3D printing allow for extensive material property enhancement and control which warrant tunable functionalities of the system. The 3D-printed structure is made of 3 rigid ball and socket joints connected in series and actuated by integrating twisted and coiled polymer fishing line ( TCPFL) actuators, which are con fined in the FGM accordion-shaped channels. The implementation of the untethered T CPFL actuation system can be highly bene ficial for deployment in environments that require low vibrations and silent actuation. The fishing line TCP actuators produce an actuation strain up to 40% and bend the joint up to 40° in any direction. The T CPFL can be actuated individually or as a group to control the bending trajectory of the modular joint, which is bene ficial when deployed in areas that contain small crevices. Obtaining complex modes of bending, the FGM multidirectional joint demonstrated a great potential to achieve di fferent functionalities such as crawling, rolling, swimming, or underwater exploration.
基金provided by the Junta de Andalucí'a for the research project P07TEP-03115 titled Biomeca'nica de la Mandí'bula Humana,for which this articlehas been prepared
文摘A finite element model of the temporomandibular joint(TMJ)and the human mandible was fabricated to study the effect of abnormal loading,such as awake and asleep bruxism,on the articular disc.A quasilinear viscoelastic model was used to simulate the behaviour of the disc.The viscoelastic nature of this tissue is shown to be an important factor when sustained(awake bruxism)or cyclic loading(sleep bruxism)is simulated.From the comparison of the two types of bruxism,it was seen that sustained clenching is the most detrimental activity for the TMJ disc,producing an overload that could lead to severe damage of this tissue.
文摘Septic arthritis of the temporomandibular joint (TMJ) is a rare disease that is characterized by preauricular pain, edema, malocclusion, trismus and abscess formation in the TMJ region. An 85-year-old male visited our hospital with the complaint of left-sided TMJ swelling, pain and trismus. Septic arthritis of the left TMJ was diagnosed on the basis of considerable elevation of CRP (Creactive proteins) and CT imaging findings. The patient was treated with oral Faropenem at 450 mg daily, but CRP increased three days after the initial visit. He was hospitalized and treated with intravenous administration of cefazolin at 2 g and clindamycin at 1.2 g daily for six days. Propionibacterium species and Veillonella species grew in a culture of the joint aspirate, but there was no apparent source of infection. After acute infectious symptoms had passed, the patient was treated with oral amoxicillin at 750 mg daily for eight weeks and was instructed to do jaw opening exercise. The patient was discharged on the 11th hospital day. After three weeks of the hospital discharge, the patient healed completely. To avoid serious complications, clinicians should include septic arthritis of the TMJ in the differential diagnosis of preauricular pain, trismus and swelling.
文摘Treatment of bone tumors in the mandible often involves extensive excavation of affected bone, followed by mandibular reconstruction. Prosthetic implants may be needed to restore jaw functionality. The challenges of making prosthetic bone implants include stress shielding and extending the mechanical life of the implant. We have developed a design algorithm to improve the efficiency of prosthesis design. A finite element model of the patient case is constructed from a computer tomography scan, and the computer implements topology optimization techniques to design the prosthesis with limited stress shielding affected by highly biomechanical compatibility. Topology optimization facilitates the design of low weight structures by automatically introducing holes into the structure. This is governed by engineering predetermined constraints to meet certain job specifications. Such a design will be tested for fatigue life before it is ready to be manufactured and used. Topology optimization can be performed as a design process to achieve a final design that takes stress shielding into consideration. The problem of stress shielding is solved by matching the stiffness of the orthopedic implant to the original bone that is being replaced. The material we used was titanium alloy (Ti-6Al-7Nb). Volume fraction of the orthodox implant was used (0.2872 for the studied case) as volume constraints. Compliance of the bulk bone was set as a further constraint to match the stiffness of the bone with the designed structure. Our results show a good life expectancy for the designed parts, with 12% higher life expectancy for stress-based topology optimization than for compliance-based topology optimization.
文摘BACKGROUND The role of occlusal factors on the occurrence of temporomandibular joint disorders(TMDs)is still unclear and it is tricky for orthodontists to treat malocclusions in patients with TMDs.We report the case of the second orthodontic treatment of an adult female with Class II division 2 malocclusion associated with TMD.With the removal of anterior occlusal interference,TMD symptoms were alleviated and cone beam computed tomography(CBCT)images showed the bilateral condyles shifted forward.CASE SUMMARY This case report presented an orthodontic retreatment of an adult female with TMD and mandibular backward positioning based on CBCT examination and Joint Space Index(JSI)analysis.The left and right JSI values of-38.5 and-52.6 indicated that the position of bilateral condyles had posterior displacement.Ten years prior to this evaluation,she underwent orthodontic treatment resulting in the extraction of two upper premolars and one lower central incisor.The joint symptoms,including pain and sounds,were alleviated along with verified mandibular forward repositioning by extraction of another lower central incisor.CONCLUSION Mandibular backward positioning could be associated with TMD.JSI analysis based on CBCT is a convenient way to examine condylar positions quantitatively.
文摘BACKGROUND Condylar osteophytes,a remodeling form of temporomandibular joint osteoarthritis(TMJ OA),mainly manifest as marginal angular outgrowths of the condyle.Previous researchers have advocated surgical removal of condylar osteophytes.Reports on the effect of occlusal splint on TMJ OA patients’joints have mostly focused on treatment with this splint,which can reduce the absorption of the affected condyle and promote repair and regeneration.However,the effect of the splint on the dissolution of condylar osteophytes has not yet been reported.CASE SUMMARY A 68-year-old female patient suffered from occlusal discomfort with left facial pain for 2 years.Cone beam computed tomography showed a rare osteophyte on top of her left condyle.She was finally diagnosed with TMJ OA.The patient refused surgical treatment and received conservative treatment with a muscle balance occlusal splint.The pain experienced by the patient on the left side of her face was relieved,and her chewing ability recovered after treatment.The osteophyte dissolved,and the condylar cortex remained stable during long-term follow-up observations.CONCLUSION The muscle balance occlusal splint could be a noninvasive means of treating condylar osteophytes in TMJ OA patients.
文摘This article reviews the imaging anatomy of temporomandibular joint(TMJ), describes the technique of multi-detector computed tomography(MDCT) of the TMJ, and describes in detail various osseous pathologic afflictions affecting the joint. Traumatic injuries affecting the mandibular condyle are most common, followed by joint ankylosis as a sequel to arthritis. The congenital anomalies are less frequent, hemifacial microsomia being the most commonly encountered anomaly involving the TMJ. Neoplastic afflictions of TMJ are distinctly uncommon, osteochondroma being one of the most common lesions. MDCT enables comprehensive evaluation of osseous afflictions of TMJ, and is a valuable tool for surgical planning. Sagittal, coronal and 3D reformatted images well depict osseous TMJ lesions, and their relationship to adjacent structures.
文摘Background: Pigmented villonodular synovitis is a rare condition typically affecting the major joints and the involvement of the temporomandibular joint is rare. Although, it is histologically benign, it can be locally aggressive, capable of extensive bone destruction. The disease has aggressive behavior and a high incidence of recurrence (40% - 60%). Case report: A 35 years old male presented with history of unilateral hearing loss and otalgia of six month duration. On examination, there was a soft bulge in the superior wall of external auditory canal. Contrast enhanced CT scan showed soft tissue density occupying the right external auditory canal and bulging into the middle ear cavity, displacing the intact ossicular chain medially with evidence of destruction of the posterior wall of the external auditory canal, glenoid fossa, mastoid bone and the scutum. The squamous part of the right temporal bone showed evidence of lateral bowing with discontinuity. Surgical resection was done through post aural approach. Histopathological examination revealed pigmented villonodular tenosynovitis which stained positive for CD 68. Post operatively patient was evaluated clinically and with radiological modalities which showed healthy mastoid cavity and no increase in post operative granulations on magnetic resonance imaging. Conclusion: Pigmented villonodular tenosynovitis of temporomandibular joint is a rare entity. Due to the aggressive behavior of the lesion, radical or aggressive surgical resection should be done. Long term follow up with radiological modality should be done due to the high recurrence rate.
基金supported by the National Earthquake Science Experiment in Sichuan and Yunnan Provinces of China(#2016 CESE 0201)National Natural Science Foundation of China(#41574034)China National Special Fund for Earthquake Scientific Research in Public Interest(#201508008)
文摘Accurate determination of seismic velocity of the crust is important for understanding regional tectonics and crustal evolution of the Earth. We propose a stepwise joint linearized inversion method using surface wave dispersion, Rayleigh wave ZH ratio(i.e., ellipticity), and receiver function data to better resolve 1D crustal shear wave velocity(v_S) structure. Surface wave dispersion and Rayleigh wave ZH ratio data are more sensitive to absolute variations of shear wave speed at depths, but their sensitivity kernels to shear wave speeds are different and complimentary. However, receiver function data are more sensitive to sharp velocity contrast(e.g., due to the existence of crustal interfaces) and v_P/v_S ratios. The stepwise inversion method takes advantages of the complementary sensitivities of each dataset to better constrain the v_S model in the crust. We firstly invert surface wave dispersion and ZH ratio data to obtain a 1D smooth absolute v_S model and then incorporate receiver function data in the joint inversion to obtain a finer v_S model with better constraints on interface structures. Through synthetic tests, Monte Carlo error analyses, and application to real data, we demonstrate that the proposed joint inversion method can resolve robust crustal v_S structures and with little initial model dependency.
