Research progress of finite element method in the biomechanics of the orbit / 国际眼科杂志(Guoji Yanke Zazhi)

The finite element method(FEM)is a widely employed mathematical technique in mechanical research that divides an object into discrete and interacting finite elements. Medically, finite element analysis(FEA)enables the simulation of biomechanical experiments that are challenging to conduct. Orbital surgery poses significant challenges to ophthalmologists due to its inherent difficulty and steep learning curve. FEM enables the simulation and analysis of the mechanical properties of orbital tissue, offering a novel approach for diagnosing and treating orbital-related diseases. With technological advancements, FEM has significantly matured in the diagnosis and treatment of orbital diseases, becoming a popular area of research in orbital biomechanics. This paper reviewed the latest advancements in orbital FEM, encompassing the development of orbital FEA models, simulation of orbital structure, and its application in orbital-related diseases. Additionally, the limitations of FEM and future research directions are also discussed. As a digital tool for auxiliary diagnosis and treatment, orbital FEA will progressively unlock its potential for diagnosing and treating orbital diseases alongside technological advancements.

Effect of small incision lenticule extraction on the treatment of myopia patients and the impact on corneal biomechanics / 国际眼科杂志(Guoji Yanke Zazhi)

AIM:To investigate the effect of small incision lenticule extraction(SMILE)on the treatment of myopia patients, and the impact on corneal biomechanics.METHODS:Retrospective study. A total of 120 myopic patients(240 eyes)who were scheduled to undergo corneal refractive surgery in Anyang Eye Hospital from January 2020 to December 2021 were selected. The patients were divided into SMILE group(64 patients, 128 eyes)and transepithelial photorefractive keratectomy(TransPRK)group(56 patients, 112 eyes)according to the surgical treatment method. The two groups were compared in terms of uncorrected visual acuity, corneal biomechanics, corneal endothelial cell count, posterior corneal surface height and corneal surface regularity index at 1, 7 d, 1, 3, 6 mo and 1 a after surgery, and surgical complications.RESULTS:The uncorrected visual acuity of the SMILE group at 1, 7 d and 1 mo after surgery was better than that of the TransPRK group(all P<0.001), but there was no statistically significant difference between the groups at 3, 6 mo and 1 a after surgery(all P>0.05). Compared with preoperative values, corneal-compensated intraocular pressure, Goldmann-correlated intraocular pressure, corneal resistance factor, and corneal hysteresis in both groups showed a first decreasing and then increasing trend after surgery. The corneal-compensated intraocular pressure, Goldmann-correlated intraocular pressure, corneal resistance factor, and corneal hysteresis in the SMILE group at 1, 7 d and 1 mo after surgery were higher than those in the TransPRK group(all P<0.05), but there was no statistically significant difference between the groups at 3, 6 mo and 1 a after surgery(all P>0.05). There were no significant changes of corneal endothelial cell count and corneal posterior surface height in the two groups after surgery(all P>0.05). Furthermore, corneal surface regularity index of the two groups showed a first increasing and then decreasing trend after surgery, with no statistically significant difference between the groups(P>0.05), and there was no statistically significant difference in the incidence of postoperative complications between the groups(P>0.05).CONCLUSION:Compared with TransPRK, SMILE has less influence on corneal biomechanics, and better visual recovery in the early stage. There is no difference in long-term visual acuity between the two surgeries, and both have good safety and effectiveness.

Research progress on biomechanics for internal fixation in tibial plateau fracture / 中国修复重建外科杂志

OBJECTIVE@#To review the biomechanical research progress of internal fixation of tibial plateau fracture in recent years and provide a reference for the selection of internal fixation in clinic.@*METHODS@#The literature related to the biomechanical research of internal fixation of tibial plateau fracture at home and abroad was extensively reviewed, and the biomechanical characteristics of the internal fixation mode and position as well as the biomechanical characteristics of different internal fixators, such as screws, plates, and intramedullary nails were summarized and analyzed.@*RESULTS@#Tibial plateau fracture is one of the common types of knee fractures. The conventional surgical treatment for tibial plateau fracture is open or closed reduction and internal fixation, which requires anatomical reduction and strong fixation. Anatomical reduction can restore the normal shape of the knee joint; strong fixation provides good biomechanical stability, so that the patient can have early functional exercise, restore knee mobility as early as possible, and avoid knee stiffness. Different internal fixators have their own biomechanical strengths and characteristics. The screw fixation has the advantage of being minimally invasive, but the fixation strength is limited, and it is mostly applied to Schatzker typeⅠfracture. For Schatzker Ⅰ-Ⅳ fracture, unilateral plate fixation can be used; for Schatzker Ⅴand Ⅵ fracture, bilateral plates fixation can be used to provide stronger fixation strength and avoid the stress concentration. The intramedullary nails fixation has the advantages of less trauma and less influence on the blood flow of the fracture end, but the fixation strength of the medial and lateral plateau is limited; so it is more suitable for tibial plateau fracture that involves only the metaphysis. Choosing the most appropriate internal fixation according to the patient's condition is still a major difficulty in the surgical treatment of tibial plateau fractures.@*CONCLUSION@#Each internal fixator has good fixation effect on tibial plateau fracture within the applicable range, and it is an important research direction to improve and innovate the existing internal fixator from various aspects, such as manufacturing process, material, and morphology.

Stress distribution in peri-implant bone, implants, and prostheses: 3D-FEA of marginal bone loss and prosthetic design / Distribuição de estresse no osso peri-implantar, implantes e próteses: análise 3D-FEA de perda óssea marginal e design protético

Objective: In response to the demand for dental implants, extensive research has been conducted on methods for transferring load to the surrounding bone. This study aimed to evaluate the stresses on the peripheral bone, implants, and prostheses under scenarios involving of the following variables: prosthesis designs, vertical bone heights, load angles, and restorative materials. Material and Methods: Three implants were inserted in the premolar and molar regions (5-6-7) of the two mandibular models. Model 1 represented 0 mm marginal bone loss and Model 2 simulated 3 mm bone loss. CAD/CAM-supported materials, hybrid ceramic (HC), resin-nano ceramic (RNC), lithium disilicate (LiSi), zirconia (Zr), and two prosthesis designs (splinted and non-splinted) were used for the implant-supported crowns. Forces were applied vertically (90°) to the central fossa and buccal cusps and obliquely (30°) to the buccal cusps only. The stresses were evaluated using a three-dimensional Finite Element Analysis. Results: Oblique loading resulted in the highest stress values. Of the four materials, RNC showed the low stress in the restoration, particularly in the marginal area. The use of different restorative materials did not affect stress distribution in the surrounding bone. The splinted prostheses generated lower stress magnitude on the bone, and while more stress on the implants were observed. Conclusion: In terms of the stress distribution on the peri-implant bone and implants, the use of different restorative materials is not important. Oblique loading resulted in higher stress values, and the splinted prosthesis design resulted in lower stress (AU)

Objetivo: Em resposta à demanda por implantes dentários, extensa pesquisa foi realizada sobre métodos para transferir carga ao osso circundante. Este estudo buscou avaliar os estresses no osso periférico, implantes e próteses em cenários que envolvem as seguintes variáveis: designs de próteses, alturas ósseas verticais, ângulos de carga e materiais restauradores. Material e Métodos: Três implantes foram inseridos nas regiões dos pré-molares e molares (5-6-7) de dois modelos de mandíbula. O Modelo 1 representou perda óssea marginal de 0 mm e o Modelo 2 simulou perda óssea de 3 mm. Materiais suportados por CAD/CAM, cerâmica híbrida (HC), cerâmica nano-resina (RNC), dissilicato de lítio (LiSi), zircônia (Zr) e dois designs de próteses (sintetizadas e não-sintetizadas) foram utilizados para as coroas suportadas por implantes. Forças foram aplicadas verticalmente (90°) à fossa central e cúspides bucais e obliquamente (30°) apenas às cúspides bucais. Os estresses foram avaliados usando Análise de Elementos Finitos tridimensional. Resultados: Cargas oblíquas resultaram nos valores mais altos de estresse. Entre os quatro materiais, RNC mostrou baixo estresse na restauração, especialmente na área marginal. O uso de diferentes materiais restauradores não afetou a distribuição de estresse no osso circundante. Próteses sintetizadas geraram menor magnitude de estresse no osso, enquanto mais estresse nos implantes foi observado. Conclusão: Em termos de distribuição de estresse no osso peri-implantar e implantes, o uso de diferentes materiais restauradores não é crucial. Cargas oblíquas resultaram em valores mais altos de estresse, e o design de prótese sintetizada resultou em menor estresse. (AU)

Assessing the effect of prophylactic ankle taping on ankle and knee biomechanics during landing tasks in healthy individuals: A cross-sectional observational study

ABSTRACT BACKGROUND: Current research supports the fact that prophylactic ankle taping (AT) is effective in preventing ankle injuries in amateur and elite sports athletes. OBJECTIVE: This study aimed to investigate the effect of AT on balance, knee valgus during drop jump and single-leg countermovement jump (SL-CMJ) landings, and ankle range of motion (ROM) restriction in healthy participants. DESIGN AND SETTING: A cross-sectional observational study was conducted at the Universidad Europea de Madrid, Madrid, Spain. METHODS: Participants: Thirty-nine healthy individuals participated in this study and performed the movements under two conditions (with and without tape). Outcome measurements: ankle ROM, balance, SL-CMJ height, flight time, ground time, and knee valgus. Before any intervention, a random process was developed with a 1:1 allocation ratio, and the participants were assigned to groups A (tape-no tape) and B (no tape-tape). RESULTS: Significant differences between tape and no-tape moments were observed for drop jump knee valgus flexion (P = 0.007), with an increase in knee valgus in participants with ankle taping. Similarly, the Y-balance testshowed a significant decrease in all variables (P = 0.001 and), ankle dorsiflexion (P = 0.001) in participants with ankle taping. CONCLUSIONS: AT is effective for immediate ankle ROM restriction. However, an increase in knee valgus during drop jump task and a decrease in lower limb balance were observed during drop jump task. Based on these results, it can be concluded that AT application in healthy individuals should not be recommended as it results in increase in injury risk factors.

Is ankle taping effective to limit the ankle dorsiflexion in a single-training session? An observational study in semi-professional basketball players

ABSTRACT BACKGROUND: Ankle taping (AT) is effective in preventing ankle sprain injuries in most common sports and is employed in rehabilitation and prevention sports. OBJECTIVE: This study aimed to investigate the effectiveness of AT to restricting excessive frontal plane ankle movements in semi-professional basketball players throughout the training session. DESIGN AND SETTING: A cross-sectional study was performed at the Universidad Europea de Madrid. METHODS: Forty male and female semi-professional basketball players were divided into two groups. The ankle dorsiflexion range of motion (ROM) and interlimb asymmetries in a weight-bearing lunge position were evaluated at four time points: 1) with no tape, 2) before practice, at 30 min of practice, and 3) immediately after practice. RESULTS: In male basketball players, no differences were observed in the right and left ankles between the baseline and 30 min and between baseline and 90 min of assessment. In female athletes, significant differences were reported between baseline and pre-training assessments for the right ankle and also significant differences between baseline and 90 min in both ankles. CONCLUSIONS: Ankle taping effectively decreased the ankle dorsiflexion ROM in male and female basketball players immediately after application. However, ROM restriction was very low after 30 and 90 min, as assessed in a single basketball practice. Therefore, the classic taping method should be revised to develop new prophylactic approaches, such as the implementation of semi-rigid bracing techniques or the addition of active stripes during training or game pauses.

La biomecánica aplicada a la técnica de pitcheo en lanzadores de béisbol

El deporte como fenómeno social, se desarrolla en la actualidad simultáneamente con los adelantos de la ciencia y la tecnología; en este contexto, juega un papel importante la biomecánica que asegura las bases para un verdadero entrenamiento técnico, de ahí que el trabajo está dirigido al uso de la biomecánica en la técnica de pitcheo. Para dar respuesta a esta temática se concibe como objetivo aplicar estudios biomecánicos a la técnica de pitcheo en los lanzadores del equipo de béisbol La Isla de la Juventud. Se utilizaron como métodos el análisis de documentos, la revisión bibliográfica, la observación científica, la entrevista y la técnica del análisis de video con ayuda de un Dron; ello permitió medir magnitudes y valorar el comportamiento de las características que poseen los movimientos ejecutados por los lanzadores objeto de estudio. También, se emplearon dos técnicas de mediciones, una a través de la filmación y otra por procesamiento cinemático con el uso de los softwares como Tracker y Kinovea. La muestra estuvo conformada por ocho sujetos, distribuidos en tres atletas, dos entrenadores y tres investigadores; esto permitió determinar las características de la distancia de paso, ángulo que forma el brazo de lanzar con respecto a la cabeza, altura de la pelota y la velocidad de la pelota ejecutados por los lanzadores investigados.

O esporte, como fenômeno social, está se desenvolvendo simultaneamente com os avanços da ciência e da tecnologia; nesse contexto, a biomecânica desempenha um papel importante para garantir a base de um verdadeiro treinamento técnico, portanto, o trabalho visa ao uso da biomecânica na técnica de arremesso. Para responder a essa questão, o objetivo foi aplicar estudos biomecânicos à técnica de arremesso nos arremessadores do time de beisebol La Isla de la Juventud. Os métodos utilizados foram a análise de documentos, a revisão bibliográfica, a observação científica, a entrevista e a técnica de análise de vídeo com a ajuda de um drone, o que permitiu medir as magnitudes e avaliar o comportamento das características dos movimentos executados pelos arremessadores em estudo. Além disso, foram utilizadas duas técnicas de medição, uma por meio de filmagem e outra por meio de processamento cinemático com o uso de softwares como o Tracker e o Kinovea. A amostra foi composta por oito sujeitos, distribuídos em três atletas, dois técnicos e três pesquisadores, o que nos permitiu determinar as características da distância de arremesso, do ângulo do braço de arremesso em relação à cabeça, da altura da bola e da velocidade da bola executada pelos arremessadores investigados.

Sport as a social phenomenon, currently develops simultaneously with the advances of science and technology; in this context, biomechanics plays an important role that ensures the bases for true technical training; hence the work is directed to the use of biomechanics in throwing technique. To respond to this issue, the objective is to apply biomechanical studies to the throwing technique in the throwers of the La Isla de la Juventud baseball team. Document analysis, bibliographic review, scientific observation, interview and the technique of video analysis with the help of a drone were used as methods; this made it possible to measure magnitudes and assess the behavior of the characteristics of the movements executed by the throwers under study. Also, two measurement techniques were used, one through filming and the other by kinematic processing with the use of software such as Tracker and Kinovea. The sample consisted of eight subjects, divided into three athletes, two coaches and three researchers; this allowed to determine the characteristics of the throw distance, the angle formed by the throwing arm with respect to the head, the height of the ball, and the speed of the ball executed by the investigated throwers.

Fatigue-life and stress distribution of a glass-ceramic under different loading conditions

Abstract This study aimed to evaluate the effect of different loading conditions on the mechanical behavior and stress distribution of a leucite-reinforced glass-ceramic. Plate-shaped ceramic specimens were obtained from leucite-reinforced glass-ceramic (1.5 × 8.4 × 8.3 mm) and adhesively cemented to a dentin analog substrate. Monotonic and cyclic contact fatigue tests were performed to simulate sphere-to-flat contact, using a 6 mm diameter spherical piston; and flat-to-flat contact, using a 3 mm diameter flat piston. For the monotonic test (n=20), a gradual compressive load (0.5 mm/min) was applied to the specimen using a universal testing machine. Failure load data were analyzed with Weibull statistics. The cyclic contact fatigue test was performed using protocols (load and a number of cycles) defined by the boundary technique (n=30). Fatigue data were analyzed using an inverse power law relationship and Weibull-lifetime distribution. The stress distribution was investigated using Finite Element Analysis (FEA). The monotonic and the fatigue Weibull modulus were similar among the two contact conditions. In fatigue, the slow crack growth exponent was greater for sphere-to-flat contact, which indicates that the load level had a greater effect on the specimen's probability of failure. In conclusion, FEA showed different stress distribution for the tested loading conditions. The stress distribution and probability of fatigue failure of specimens tested in sphere-to-flat contact showed greater dependency to load level.

Resumo O objetivo deste estudo é avaliar o efeito de diferentes condições de carregamento no comportamento mecânico e na distribuição de tensões de uma vitrocerâmica reforçada com leucita. Amostras cerâmicas em forma de lâminas foram obtidas a partir de vitrocerâmica reforçada com leucita (1,5 × 8,4 × 8,3 mm) e cimentadas adesivamente a um substrato análogo de dentina. Ensaios de carga de compressão monotônica e fadiga foram realizados para simular o contato esfera-plano, usando um pistão esférico de 6 mm de diâmetro; e contato plano com plano, usando um pistão plano de 3 mm de diâmetro. Para o ensaio de carga de compressão monotônica (n=20), foi aplicada uma carga compressiva gradual (0,5 mm/min) ao corpo-de-prova usando uma máquina de ensaio universal. Os dados de carga de fratura foram analisados de acordo com a distribuição de Weibull. O teste de fadiga foi realizado com os protocolos (carga e número de ciclos) definidos pela técnica de boundary (n=30). Os dados de fadiga foram analisados usando uma relação de tempo de vida - tensão de lei da potência inversa (IPL- inverse power law). A distribuição de tensões foi investigada usando análise de elementos finitos (AEF). O módulo de Weibull para teste de compressão monotônico e de fadiga foram semelhantes entre as duas condições de contato. Em fadiga, o expoente de crescimento sub-crítico da trinca foi maior para o contato esfera-plano, o que indica que o nível de carga teve um efeito maior na probabilidade de falha do corpo-de-prova. Em conclusão, AEF apresentou distribuição de tensões diferente para as condições de carregamento testadas. A distribuição de tensões e a probabilidade de falha em fadiga dos corpos-de-prova testados utilizando o contato esfera-plano apresentaram maior dependência do nível de carga.

Orthodontic aligners: between passion and science

ABSTRACT Introduction: The benefits and safety of using orthodontic aligners have been reported more by clinical experience and expert opinion than by scientific evidence. Another important aspect is that aligners are constantly evolving. It is important to obtain evidence that allows for new updates in manufacturing technology, in the development of new movement planning protocols, in the incorporation and design of attachments, and in the aid of skeletal anchorage. Methods: Evidence retrieved from six electronic databases (CINAHL, MEDLINE, EMBASE, Psych Info, the Cochrane Library and the Joanna Briggs Library) is presented by means of questions and answers. Conclusions: There is evidence that the aligners presented different levels of difficulty in performing each type of movement, with rotational and vertical movements being the most difficult to perform. Regarding perception of pain due to tooth movement, it seems to have less impact at the beginning of treatment; but dealing with more phonoarticulatory changes seems to require more treatment time in more complex cases. Aligners do not prevent the occurrence of root resorption, although the incidence and severity of resorption may be reduced, making oral hygiene easier and accepting the risk of white spots, caries and periodontal disease. Given the conflicting evidence, the release of bisphenol-A from the aligner cannot be denied. Solutions must be found to reduce the environmental impact of aligners disposal. There is an urgent need for well-designed randomized controlled trials.

RESUMO Introdução: As vantagens e desvantagens do uso de alinhadores ortodônticos têm sido reportadas com base mais na experiência clínica e opinião de experts do que em evidências científicas. Outro aspecto importante é que os alinhadores estão em processo de evolução constante. Assim, torna-se importante obter evidências recentes, que abranjam as novas atualizações na tecnologia de confecção, no desenvolvimento de novos protocolos de planejamento para as movimentações, a incorporação e desenho dos attachments e o auxílio da ancoragem esquelética. Métodos: As evidências encontradas em seis bases de dados eletrônicas (CINAHL, MEDLINE, EMBASE, Psych Info, Biblioteca Cochrane e Biblioteca Joanna Briggs) serão apresentadas por meio de perguntas e respostas. Conclusões: Há evidências de que os alinhadores apresentam diferentes níveis de dificuldade para realizar cada tipo de movimento, sendo os movimentos rotacionais e verticais os mais difíceis de serem executados. Quanto à percepção da dor causada pela movimentação dentária, parece haver menos impacto no início do tratamento, mas os alinhadores produzem mais alterações fonoarticulatórias e parecem exigir mais tempo de tratamento em casos mais complexos. Não há evidência de diferença na estabilidade pós-tratamento, e os alinhadores não impedem a ocorrência de reabsorção radicular, apesar da incidência e a gravidade da reabsorção poderem ser menores, facilitam a higiene bucal, reduzindo o risco de manchas brancas, cáries e doenças periodontais. Dada a evidência conflitante, a liberação de bisfenol-A pelo alinhador não pode ser negada. É preciso encontrar soluções que reduzam o impacto ambiental do descarte dos alinhadores. Há uma necessidade urgente de ensaios clínicos randomizados bem desenhados.

Efficacy of epithelial-off accelerated corneal cross-linking in the treatment of advanced keratoconus / 国际眼科杂志(Guoji Yanke Zazhi)

AIM: To investigate the efficacy of epithelial-off accelerated corneal cross-linking(CXL)in the treatment of advanced keratoconus.METHODS: A retrospective study was performed on data collected from 32 patients(43 eyes)with advanced keratoconus who underwent epithelial-off accelerated CXL at Ningxia Eye Hospital from April 2020 to December 2021. Slit-lamp, intraocular pressure, uncorrected visual acuity(UCVA), corrected visual acuity, specular microscope, Pentacam and Corvis ST were tested before and at 1, 3 and 6mo after surgery. Preoperative and postoperative corneal condition, UCVA, best corrected visual acuity(BCVA)and the values of corneal endothelial, maximum keratometry(Kmax), thinnest corneal thickness(TCT), anterior and posterior surfaces of the cornea K1, K2, biomechanically corrected intraocular pressure(bIOP), applanation time 1(A1T), applanation length 1(A1L), applanation velocity 1(A1V), applanation time 2(A2T), applanation length 2(A2L), applanation velocity 2(A2V), highest concavity deformation amplitude(HCDA), radius at highest curvature(HCR), highest concavity peak distance(HCPD)and stiffness parameter at first applanation(SP-A1)were recorded.RESULTS: There were differences between UCVA(LogMAR; 1.06±0.49, 0.78±0.39)and BCVA(LogMAR; 0.48±0.34, 0.38±0.29)before and at 6mo after surgery(P<0.05), but there were no differences in corneal endothelial cells(2917.39±288.38 vs. 2959.19±336.27 cells/mm2, P=0.477). There were differences among Kmax, TCT, anterior surface K1 and K2 and posterior surface K1 before and after surgery(P<0.05), and all increased at 1mo after surgery then returned to preoperative level at 3mo after surgery, while there was no difference in the posterior K2. Furthermore, there were statistical significance in A1T, HCPD and SP-A1 before and after surgery(P<0.05), while there were no statistical significance in A1L, A1V,A2T, A2L, A2V, HCDA, HCR and bIOP(P>0.05).CONCLUSION: Epithelial-off accelerated CXL can prevent the progression of keratoconus within half year after surgery, and it has certain safety.

The anatomical limit and strategies for molar movement during orthodontic treatment / 口腔疾病防治

@#In many cases, tooth movement over a considerable distance is needed to meet the major goal of orthodontic treatment, which has always been to correct malocclusion and improve the facial profile in patients with skeletal malocclusion. However, tooth movement over a considerable distance also carries risks of dehiscence, fenestration, root exposure, and so forth. The reason lies in neglecting many limits for tooth movement, especially anatomical characteristics. This review focuses on structural limits for orthodontic molar movement, such as the alveolar cortex, the maxillary sinus floor, and the mandibular canal. In addition, we set the strategy in clinical orthodontics. For the alveolar cortex and the mandibular canal, orthodontists are recommended to move the root away from the cortical bone initially and formulate personalized molar movement plans according to clinical examination and cone-beam computed tomography (CBCT) and other imaging examinations. First, the molar root was controlled by torque away from the bone plate, and then, the molar movement amount and direction were controlled according to the personalized movement path. In regard to the maxillary sinus floor, light and continuous forces and scientific biomechanics are suitable for bodily tooth movement. In summary, better therapeutic efficacy and long-term stabilization could be achieved by circumventing the limits and risks caused by anatomical limitations and characteristics.

Progress in Biomechanics and Mechanobiology of Dendritic Cells / 医用生物力学

Dendritic cells (DCs) are now known as the most powerful antigen-presenting cells in vivo, with efficient antigen uptaking, and processing capabilities. They can present antigens to naïve T cells in secondary lymphoid tissues, thereby induce immune response or tolerance, and play a key role in initiating and amplifying innate and adaptive immunity. DCs experience complex chemical and mechanical microenvironment changes and show different mechanophenotypes and immunophenotypes in the process of exerting their physiological functions. Deeply understanding the chemical and mechanical factors that regulate the mechanophenotypes and immunophenotypes of DCs is a prerequisite for using DCs to treat immune related diseases. In this review, the progress in the biomechanics and mechanobiology research of DCs was mainly introduced, and their potential applications and future development directions in the treatment of immune related diseases were explored.

Advances in Cardiovascular Biomechanics and Mechanobiology Research in 2022 / 医用生物力学

The cardiovascular system plays a crucial role in the entire organism. It performs many important functions, such as providing organs and tissues with nutrients, hormones, delivering oxygen to cells, and maintaining physiological temperature. For a long time, accurately identifying the nonlinear and anisotropic mechanical properties of the vascular wall within the body has been regarded as a key challenge in cardiovascular biomechanics, as these properties are critical determinants of overall cardiac function. Currently, the roles of mechanical and tissue properties in cardiovascular diseases such as arterial aneurysms and atherosclerosis remain hot topics in both basic and clinical researches. This review aims to summarize the latest research advances in the field of cardiovascular biomechanics and mechanobiology in the year 2022. In terms of cardiovascular biomechanics, researchers focus on the structure, function, and pathophysiology of the cardiovascular system, and use experimental methods such as mechanical modeling to study these issues. These include studies about biomechanical properties of diseases such as atherosclerosis, arterial aneurysms, and myocardial infarction, as well as the development and testing of treatment methods based on dynamics of the cardiovascular system. In terms of mechanobiology, researchers explore mechanical properties of cardiovascular cells and extracellular matrix, including prediction of cell mechanical properties based on machine learning, studies of biological material mechanical properties, and the role of mechanical properties in cardiovascular cell phenotype changes. These research findings provide new ideas and methods for diagnosing and treating cardiovascular diseases and offer new insights into researches in biomechanics and mechanobiology fields.

Advances in Mechanotransduction Pathway of Macrophage / 医用生物力学

Mechanical stimulation in micro-environment ( such as matrix stiffness, surface topography, cyclical stretch) can be perceived by macrophages through receptors on cell membrane, transmitted to the nucleus along the adhesion protein molecular chain and cytoskeleton, and also converted into biochemical signal to stimulate gene transcription. Mechanical stimulation drives various biological functions in macrophages, such as adhesion, proliferation, migration, and polarization, thereby playing a corresponding role in disease progression and tissue regeneration. This study demonstrates the role of micro-environment mechanics in macrophages polarization and function, and elucidates the related mechanism of mechanotransduction pathway in macrophages, so as to provide molecular biomechanics insights into the development of macrophage-targeting immunomodulatorybiomaterials.

Progress in Biomechanical Study of Rotator Cuff Repair / 医用生物力学

The rotator cuff is an important structure to maintain movement and dynamic stability of the shoulder joint. Rotator cuff injury changes its unique biomechanical effects, resulting in shoulder pain and mobility disorders. Although great progress has been made in suture technology and fixation method, the rate of postoperative retear is still very high. Understanding the biomechanical mechanism of normal rotator cuff and restoring the special biomechanical effect of rotator cuff after injury are the key to prevent postoperative retear. This article reviewed biomechanical researches on rotator cuff repair in recent years, in order to provide some theoretical guidance for clinical operation.

Biomechanical Characteristics of Idiopathic Pulmonary Fibrosis / 医用生物力学

Idiopathic pulmonary fibrosis (IPF) is a common chronic interstitial fibrotic disease. During the fibrosis process, myofibroblasts are abnormally activated, collagen is deposited in large quantities and the biomechanical characteristics of lung tissue are significantly altered. In this paper, a systematic review about the changes in lung tissues, cellular biomechanical properties and biomechanical signals during the process of IPF was presented, and the in vitro reproduction of biomechanical features and therapeutic strategies for targeting biomechanics wassummarized, so as to provide references for clinical prevention and treatment of IPF.

Age-Related Changes of Biomechanical Properties for Limb Bones in Male Rats / 医用生物力学

Objective To investigate the age-related changes of biomechanical properties for humerus, femur and tibia in male rats and their application values in age estimation. Methods According to different weeks of age, 90 healthy male SD rats were divided into 2, 4, 6, 8, 17, 26, 52, 78 and 104-week groups with 10 rats in eachgroup. After the rats were executed by excessive anesthesia, humerus, femur, and tibia were separated and the attached soft tissues were removed. The length of the above-mentioned bones and the diameter of the middle section (compression site) were measured with vernier caliper, and the three-point bending test was conducted with electronic universal material testing machine to detect the ultimate load and displacement under ultimate load. Results There were significant differences in the ultimate load of humerus, femur and tibia among male rats in different age groups (P<0. 05). With the increase of week age, the ultimate loads of the humerus, femur and tibia increased first and then decreased, and reached the peak value in 52-week age group, showing a strong positive correlation with week age before 52 weeks ( r = 0. 884,0. 933,0. 929, P<0. 05). There was no significant difference in humerus and tibia. The displacement of femur under ultimate load was weakly positively correlated with week age (R= 0. 406,P<0. 05). The age prediction accuracy for automatic linear modeling of ultimate load for humerus, femur, tibia and three above-mentioned bones in rats before 52-week age was 78. 2% , 86. 8% , 84. 1% and 88. 3% , respectively. There was a strong positive correlation between the length of humerus, femur and tibia and the ultimate load (R= 0. 904, 0. 897, 0. 814, P<0. 05). The diameters of humerus, femur and tibia were strongly positively correlated with the ultimate load (R = 0. 759, 0. 814 and 0. 745, P<0. 05). Conclusions The ultimate loads of humerus, femur and tibia in male rats increased first and then decreased with age, and were positively correlated with age before 52 weeks, which could be used for age inference. The highest accuracy of age estimation was ultimate loads of three bones, followed by femur. The length/ middle diameter of humerus, femur and tibia were strongly positively correlated with the ultimate load.

Biomechanical Study on Different fixation Methods of Cannulated Screws for Posterior Malleolus Fracture / 医用生物力学

Objective To study biomechanical effects of cannulated screws at different fixation angles on posterior malleolus fracture based on finite element method, so as to determine the best fixation method of cannulatedscrew. Methods The finite element model of ankle joint, including tibia, fibula, astragalus, corresponding cartilage and ligaments was reconstructed using CT images, and 1 / 2 posterior malleolus fracture model was established on the basis of verifying its validity. The biomechanical effects of cannulated screw fixation on posterior malleolus fracture fixation model were analyzed. Results Compared with 0°,5°,10°,20° fixation model, the 15° fixation model had the smallest displacement. The screw stress of 15° fixation model was lower than that of 5°, 10°, 20° fixation model, and higher than that of 0° fixation model. But when the screw fixation angle was 0°, the peak contact pressure of ankle joint was much larger than that of normal ankle joint, which was easy to cause traumatic osteoarthritis. Conclusions Cannulated screw is safe and effective for treating posterior malleolus fracture which is less than 1 / 2 fragment size. The displacement and stress of the model are different at different fixation angles of screws. When the fixation angle of screw is 15°, the biomechanical stability is the best, which can be used to guide clinical operation.

The Action Effect of Two Kinds of Lumbar Massage Obliquity Manipulation with Different Lumbar Degeneration Degrees: A Comparative Study / 医用生物力学

Objective To compare the action effect of traditional and modified lumbar massage obliquity manipulation with different degrees of lumbar degeneration. Methods The biomechanical model of quality-spring-damping system lumbar spine was established and massage forces from professional massage doctors were collected. The force was used as input of the model, and lumbar degeneration was simulated by increasing elastic coefficient of the spring and damping coefficient of the damping in the model. By using MATLAB/ Simulink simulation technology, the effects of massage obliquity manipulation ( the maximum relative displacement and maximum acceleration) with different degrees of lumbar degeneration were obtained for comparative analysis.Results When the lumbar spine was degenerative, the maximum relative displacement and maximum acceleration of each segment were obtained under two manipulations. With the increase of lumbar degenerationdegree, the maximum relative displacement and maximum acceleration of each segment under two manipulations showed a downward trend, and the attenuation rate of the maximum relative displacement and maximum acceleration of each segment under two manipulations was obtained. Conclusions When degenerative changes in the spine do not occur, the effectiveness of traditional lumbar massage obliquity manipulation is slightly better than that of modified lumbar massage obliquity manipulation, but the safety of modified lumbar massage obliquity manipulation is obviously better than that of the traditional lumbar massage obliquity manipulation, so the modified lumbar massage obliquity manipulation should be used. With the aggravation of lumbar degeneration, the action effects of two manipulations are attenuated in a power function. The attenuation rate of effectiveness of modified lumbar massage obliquity manipulation is significantly faster than that of traditional lumbar massage obliquity manipulation, indicating that the modified lumbar massage obliquity manipulation should not be used in the caseof lumbar degeneration.

Research Progress on Biomechanics and Mechanobiology of Articular Cartilage in 2022 / 医用生物力学

As a kind of elastic load-bearing connective tissues on bone surface in dynamic joints, articular cartilage can provide low wear lubrication, shock absorption, load transfer and other supporting functions, and has hierarchical fiber composite structures and excellent mechanical properties. As an avascular and aneural tissue,the degenerated articular cartilage lacks the capability of self-healing after damage. The high incidence of arthritisis still a hot spot in basic and clinical researches. Articular cartilage is a mechanical sensitive tissue, andmechanical environment will affect the development of tissues in different directions. Extensive researches onbiomechanics and mechanobiology of articular cartilage were conducted in 2022. Many studies on morphology, function and mechanical state of cartilage,as well as mechanical state of cartilage under different conditions were reported. Some cartilage-related loading devices were designed at animal, tissue and cell levels. Researches onthe repair of cartilage degeneration and injury under mechanical loads were carried out in vitro and in vivo, andsome important repair method and means were obtained. The biomechanical and mechanobiology research on articular cartilage is the basis of arthritis, cartilage defect and repair. The influence of quantitative mechanical under 4 conditions on the repair of articular cartilage injury needs further study in vivo and in vitro