Objective To investigate the influence of different cell structures on the static and dynamic mechanical performance of porous titanium alloy scaffolds,and to provide a theoretical mechanical basis for the application of scaffolds in the repair of mandibular bone defects.Methods Porous titanium alloy scaffolds with diamond,cubic,and cross-sectional cubic cell structures were manufactured using three-dimensional printing technology.Uniaxial compression tests and ratcheting fatigue with compression load tests were conducted to analyze the static and dynamic mechanical performances of scaffolds with different cell structures.Results The elastic moduli of the diamond cell,cross-sectional cubic cell,and cubic cell scaffolds were 1.17,0.566,and 0.322 GPa,respectively,and the yield strengths were 71.8,65.1,and 31.8 MPa,respectively.After reaching the stable stage,the ratcheting strains of the cross-sectional cubic,diamond,and cubic cell scaffolds were 3.3%,4.0%,and 4.5%,respectively.The ratcheting strain increased with increasing average stress,stress amplitude,and peak holding time,and decreased with increasing loading rate.Conclusions The evaluation results of the static mechanical performance showed that the diamond cell scaffold was the best,followed by the cross-sectional cubic cell scaffold and the cubic cell scaffold.The evaluation results of the dynamic mechanical performance showed that the cross-sectional cubic cell scaffold performed the best,followed by the diamond cell scaffold,whereas the cubic cell scaffold performed the worst.The fatigue performance of the scaffold is affected by the loading conditions.These results provide new insights for scaffold construction for the repair of mandibular bone defects and provide an experimental basis for further clinical applications of this scaffold technology.

Objective To analyze and compare the strength of titanium alloy crystalline porous scaffolds and porous scaffolds with a triply periodic minimal surface(TPMS)structure and explore the effect of porosity on the equivalent elastic modulus and permeability.Methods Crystalline porous scaffolds(cell 1-4)and TPMS porous scaffolds(P-,G-,D-,and FKS-type)with the same porosity were constructed,and the equivalent elastic modulus,equivalent yield strength,and permeability of the scaffolds were calculated using finite element simulation.Results The elastic modulus of eight scaffolds was in the range of 5.1-10.4 GPa,the yield strength was in the range of 69-110 MPa,and the permeability of 4 crystalline scaffolds was in the range of 0.015-0.030 mm2.Conclusions With an increase in porosity,the elastic modulus and yield strength of the scaffold gradually decreased,and the permeability gradually increased.The cell 2-type scaffold is suitable for repairing defects at load-bearing bone sites because of its high elastic modulus and yield strength.The cell 3-type scaffold with a uniform stress distribution and a longer linear elasticity phase may be suitable for designing porous tibial platforms for knee joint prostheses.

Objective To simulate the microflow field environment between the anastomotic nail surface and intestinal wall tissue after implantation and to study the effect of hydrophobic surfaces on the flow rate of extracellular fluid and the fluid shear force on the wall to regulate bacterial adhesion through changes in the flow field.Methods The microstructure of shark skin was observed,and a simplified two-dimensional(2D)movement model of bacteria in a microflow field was established.Using computational fluid dynamics(CFD)numerical simulation,the movement of bacteria on a smooth surface and micro-textured surface in a static and dynamic flow field were simulated.The flow field characteristics around bacteria and the magnitude of fluid shear force under the two surface environments were compared,and the internal mechanism of the fluid shear force affecting bacterial adhesion was analyzed.Results The addition of the biomimetic microtexture enhanced the flow rate of the extracellular fluid in the microflow field,and the fluid had little viscous effect on the bacteria in the static flow field.The fluid in the dynamic flow field had a stronger pushing effect on the bacteria.The fluid shear force on the microtextured wall increased when the pit width was within a specific range.Conclusions The bionic micro-textured surface of the anastomotic nail can accelerate the flow rate of extracellular fluid,increase the fluid shear force of micro-textured walls and bacteria,and influence bacterial adhesion.These result provide a theoretical basis for studying bacteriostatic surfaces of anastomotic nails.

Patients with severe trauma require an extremely timely treatment and transfusion plays an irreplaceable role in the emergency treatment of such patients. An increasing number of evidence-based medicinal evidences and clinical practices suggest that patients with severe traumatic bleeding benefit from early transfusion of low-titer group O whole blood or hemostatic resuscitation with red blood cells, plasma and platelet of a balanced ratio. However, the current domestic mode of blood supply cannot fully meet the requirements of timely and effective blood transfusion for emergency treatment of patients with severe trauma in clinical practice. In order to solve the key problems in blood supply and blood transfusion strategies for emergency treatment of severe trauma, Branch of Clinical Transfusion Medicine of Chinese Medical Association, Group for Trauma Emergency Care and Multiple Injuries of Trauma Branch of Chinese Medical Association, Young Scholar Group of Disaster Medicine Branch of Chinese Medical Association organized domestic experts of blood transfusion medicine and trauma treatment to jointly formulate Chinese expert consensus on blood support mode and blood transfusion strategies for emergency treatment of severe trauma patients ( version 2024). Based on the evidence-based medical evidence and Delphi method of expert consultation and voting, 10 recommendations were put forward from two aspects of blood support mode and transfusion strategies, aiming to provide a reference for transfusion resuscitation in the emergency treatment of severe trauma and further improve the success rate of treatment of patients with severe trauma.

Jupi Zhurutang originated from Synopsis of the Golden Chamber （《金匮要略》）， which consists of Pericarpium Citri Reticulatae， Caulis Bambusae in Taenia， Ginseng Radix et Rhizoma， Zingiberis Rhizoma Recens， Jujubae Fructus， and Glycyrrhizae Radix et Rhizoma and is used to treat retching. It has been put on the list of Catalogue of Ancient Classical Prescription （First Batch） released by National Administration of Traditional Chinese Medicine. With the bibliometric method， we searched the medical classics containing Jupi Zhurutang and systematically examined the information on the origin of the prescription， the indications， compatibility rule， medicinals in the prescription， dosage and usage， processing method， and decocting method. It was found that there are many versions of Jupi Zhurutang， and there are common grounds of main symptoms， pathogenesis， composition and dosage between the same prescription with different names and different prescriptions with the same name. The prescription which is closest to the original version in Synopsis of the Golden Chamber is mainly used for the treatment of stomach deficiency and qi counterflow without obvious cold or heat. According to the weights and measures， ratio of Pericarpium Citri Reticulatae， Caulis Bambusae in Taenia， Radix Ginseng， Rhizoma Zingiberis Recens， and Radix Ginseng in Synopsis of the Golden Chamber is approximately 6∶2∶8∶5∶1. The Jupi Zhurutang derived from other ancient classics such as Yanshi Jisheng Fang（《严氏济生方》） is a different prescription for hiccups caused by the stomach heat， and the ratio of Pericarpium Citri Reticulatae to Caulis Bambusae in Taenia in this prescription is about 1∶1. It is also found that cold herbs such as Red Poria， Eriobotryae Folium and Ophiopogon Japonicus are added to the formula in later generations. Therefore， the Jupi Zhurutang used in modern times is mostly modified and different from that in Synopsis of the Golden Chamber. This study summarizes the historical evolution of Jupi Zhurutang and identifies the key information， with a view to providing a reference for the rational modification of this prescription in clinical settings and further research.

During coronavirus disease 2019 epidemic, the treatment of severe trauma has been impacted. The Consensus on emergency surgery and infection prevention and control for severe trauma patients with 2019 novel corona virus pneumonia was published online on February 12, 2020, providing a strong guidance for the emergency treatment of severe trauma and the self-protection of medical staffs in the early stage of the epidemic. With the Joint Prevention and Control Mechanism of the State Council renaming "novel coronavirus pneumonia" to "novel coronavirus infection" and the infection being managed with measures against class B infectious diseases since January 8, 2023, the consensus published in 2020 is no longer applicable to the emergency treatment of severe trauma in the new stage of epidemic prevention and control. In this context, led by the Chinese Traumatology Association, Chinese Trauma Surgeon Association, Trauma Medicine Branch of Chinese International Exchange and Promotive Association for Medical and Health Care, and Editorial Board of Chinese Journal of Traumatology, the Chinese expert consensus on emergency surgery for severe trauma and infection prevention during coronavirus disease 2019 epidemic ( version 2023) is formulated to ensure the effectiveness and safety in the treatment of severe trauma in the new stage. Based on the policy of the Joint Prevention and Control Mechanism of the State Council and by using evidence-based medical evidence as well as Delphi expert consultation and voting, 16 recommendations are put forward from the four aspects of the related definitions, infection prevention, preoperative assessment and preparation, emergency operation and postoperative management, hoping to provide a reference for severe trauma care in the new stage of the epidemic prevention and control.

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

Objective To study stress relaxation behaviors of cartilage scaffolds under different degradation cycles by using finite element analysis combined with theoretical models. Methods Based on the established degradation theoretical model, the elastic modulus of the scaffold was calculated under different degradation cycles. The finite element model of cartilage scaffolds was established and stress relaxation simulation was performed to analyze the variation of scaffold relaxation stress with time. The stress relaxation constitutive model was established to predict mechanical properties of the scaffold. Results The elastic modulus of cartilage scaffolds at 14 th, 28th, 42nd, 56th day after degradation was 32. 35, 31. 12, 29. 91, 28. 74 kPa, respectively. The upper layer for cartilage scaffolds was the largest. The overall relaxation stress of the scaffold decreased rapidly with time and then tended to be stable. At 8th week after degradation, the stress which the scaffold couldwithstand was still within the physiological load range of the cartilage. The predicted results of the stress relaxation constitutive model were in good agreement with the finite element simulation results. Conclusions The elastic modulus of the scaffold gradually decreases with the increase of degradation time. The longer the degradation period is, the less stress the scaffold can withstand. At the same degradation period, the larger the applied compressive strain, the larger the stress on the scaffold. Both the finite element simulation and stress relaxation constitutive model can effectively predict stress variations of cartilage scaffolds under degradation

Objective To study the short-term variation patterns of graft viscosity after anterior cruciate ligament reconstruction (ACLR) surgery. Methods Six male New Zealand rabbits were selected. The ACLR animal model of unilateral knee was made with Achilles tendon as the graft. The experimental rabbits were euthanized 15 days after ACLR surgery, with removal of the graft, healthy anterior cruciate ligament (ACL) and Achilles tendon. The cross-sectional area and viscosity coefficient of the graft were measured, and the creep experiments were carried out under equilibrium conditions of 0.1 MPa and 1 MPa, respectively. The viscosity coefficent was calculated. Variation patterns of graft viscosity were summarize. The grafts were compared with healthy ACL. Results The cross-sectional area of the graft increased slowly within 15 days after ACLR surgery. The viscosity of ACL and graft changed nonlinearly. The viscosity coefficient was quite different under different stresses. The viscosity coefficient of the graft decreased with the time after ACLR surgery, which was more obviously under the condition of low stress. Conclusions The results are helpful to guide the implementation of early postoperative rehabilitation plan after ACLR surgery .

Cartilage surface fibrosis is an early sign of osteoarthritis and cartilage surface damage is closely related to load. The purpose of this study was to study the relationship between cartilage surface roughness and load. By applying impact, compression and fatigue loads on fresh porcine articular cartilage, the rough value of cartilage surface was measured at an interval of 10 min each time and the change rule of roughness before and after loading was obtained. It was found that the load increased the roughness of cartilage surface and the increased value was related to the load size. The time of roughness returning to the initial condition was related to the load type and the load size. The impact load had the greatest influence on the roughness of cartilage surface, followed by the severe fatigue load, compression load and mild fatigue load. This article provides reference data for revealing the pathogenesis of early osteoarthritis and preventing and treating articular cartilage diseases.
Animals ; Cartilage, Articular ; Fatigue ; Osteoarthritis/pathology* ; Pressure ; Swine