基于倾向性评分匹配分析SMILE术治疗高度近视的疗效

目的:基于倾向性评分匹配分析全飞秒小切口角膜基质透镜取出术(SMILE)治疗高度近视的疗效。方法:选取2019-05/2021-05在本院行SMILE术的高度近视患者48例48眼作为观察组,以倾向性评分匹配法进行1∶1匹配纳入行FS-LASIK术的高度近视患者48例48眼作为对照组。术后随访6mo,比较两组患者柱镜度、角膜中央厚度、裸眼视力(UCVA)、角膜内皮细胞相关指标[六边形内皮细胞百分比(6A)、内皮细胞面积的变异系数(CV)、中央角膜内皮细胞密度(ECD)]及角膜生物力学指标[模拟Goldmann眼压(IOPg)、角膜滞后量(CH)、角膜阻力因子(CRF)、角膜补偿眼压(IOPcc)]的变化,记录两组患者并发症发生情况。结果:与术前比较,两组患者术后3、6mo柱镜度和UCVA均显著改善,角膜中央厚度、角膜内皮细胞和角膜生物力学相关指标均降低,且观察组变化更为显著(均P<0.05)。随访期间,观察组和对照组并发症发生率无显著差异(8%vs 17%,P>0.05)。结论:SMILE术治疗高度近视疗效确切,有助于改善视力。

Simulation Analysis of Electromechanical Coupling for Unmanned Aerial Vehicle Cabin Door System

In order to study the dynamic response of the unmanned aerial vehicle cabin door opening and closing system under impact load conditions, considering the flexible treatment of mechanical components, and the system’s motion with different stiffness of energy-absorbing components, a rigid-flexible coupling model of the cabin door actuation system was established in LMS. Virtual. Motion. In Amesim, a control model of the motor was created. Through the Motion-Amesim co-simulation module, the dynamic module of the system was combined with the motor control module to complete the electromechanical coupling simulation and analyze the results. .

中医老年食养在医养结合养老模式中的应用优势与发展对策

随着老龄化形式的日益严峻,老年病的发病率也日渐增多.作为世界各地最主流的养老模式,医养结合值得我国学习和推广.在医养结合模式中,融入养生保健服务,已成为建设健康老龄化社会的优先选择,即符合国情,又符合养老实际需要.在长期的医疗实践中过程中,历代医家们积累了丰富的药膳食疗经验,如今社会提倡的食疗养生可以说是传统饮食文化的一种回归,应该充分发挥中医食养的独特优势,利用中医食疗对老年人生活的积极影响,为老年人的防病治病保驾护航.本文皆在研究中医老年食养对医养结合模式发展的意义,探究医养结合模式发展的新思路.

Protective Effects of Danggui Buxue Tang on a Human Umbilical Vein Endothelialcell Damage Induced by Advanced Glycation End Products

Advanced glycation end products (AGEs) have been regarded as a pivotal inducer in diabetes and kinds of diabetic nephropathy. The present studies explored the effects of Danggui Buxue Tang (DBT) that is a Chinese medicinal de- coction on negative charge to Human Umbilical Vein Endothelial Cell (HUVEC) and the related mechanism. Alcian blue staining was established to evaluate the intensity of negative charge on HUVEC. Proteoglycan expressions of AGP and avidin were determined by SDS-PAGE. We observed that DBT can significantly increase negative charge on HU-VEC and up-regulated AGP and avidin expressions and ameliorate AGEs-induced HUVEC apoptosis. Therefore, all results showed DBT had prevention effects against the progression of AGEs-induced damage, and this decoction might be promising agent against proteinuria in diabetic nephropathy.

Endovascular embolization for upper gastrointestinal bleeding due to portal hypertension caused by a superior mesenteric arteriovenous fistula

To the Editor,Upper gastrointestinal bleeding(UGIB)caused by portal hypertension is not uncommon in clinical practice,but UGIB caused by superior mesenteric arteriovenous fistula(SMAVF)is extremely rare.The primary etiologies of SMAVF are associated with traumatic or iatrogenic injury,and congenital lesions.1,2 Although many patients remain asymptomatic after unrecognized injury to the superior mesenteric artery(SMA)for many years,most previous studies reported delayed presentation of persistent epigastric pain,vomiting and nausea,ascites,mesenteric ischemia,or bleeding.The incidence of SMAVF is 0.09%,with a mortality rate of 39%–77%.3 Thus,prompt diagnosis and treatment are very important to prevent morbidity and mortality.

Mechanism Research of Chonglou as a Pain Killer by Network Pharmacology

Objective:The objective of this study is to screen the therapeutic targets of pain of traditional Chinese medicine Chonglou and explore the relevant mechanism by network pharmacology techniques and methods.Materials and Methods:The chemical components of Chonglou were collected according to chemistry database and related literature.SwissADME was used to collect the potential active ingredients from all the chemical components of Chonglou and SwissTarget Prediction was utilized to predict their targets.The genes related to pain were collected from GeneCards and Online Mendelian Inheritance in Man databases.Joint genes were uploaded to the online string database for the analysis and the PPI network was constructed.The"Chonglou-active component-target-pain"network was constructed by Cytoscape 3.7.1 software,Gene Ontology(GO)functional enrichment analysis and Kyoto Encyclopedia of Genes and Genomes(KEGG)pathway enrichment analysis were performed for key target proteins.The top three active components with most targets in the network were docked with the target proteins by the molecular docking technique.Results:A total of nine potential active compounds of Chonglou,264 potential target genes,2385 targets of pain disorder,and 128 common targets for drug and disease were screened.One hundred and thirty-one GO items were identified by the GO enrichment analysis,and 23 related signaling pathways were identified by the KEGG pathway enrichment analysis.Molecular-docking results show that pennogenin is the optimal butt ligand of PIK3 CA,STAT3,mitogen-activated protein kinase 14,and ADORA1.Conclusion:It is preliminarily revealed that Chonglou might treat pain through multiple targets,multiple biology processes and multiple pain-related signaling pathways,providing reference for the subsequent experimental research.

Reliability analysis of arresting hook engaging arresting cable for carrier-based aircraft influenced by multifactors

The carrier-based aircraft landing and arrest process is complex and nonlinear,and includes the coupling effect between the aircraft and arresting system.It has many uncertain factors,which lead to difficulty in the reliability analysis.To make the reliability analysis more accurate and effective,this paper presents some studies.Taking a certain type of carrier-based aircraft as the research object,a dynamic model of the landing and arrest cable was established,and the accuracy of the model was verified using laboratory test results.Based on the model,this paper shows how the key parameters,including the sinking velocity,pitch angle and horizontal velocity,affect the collision rebound performance of the arresting hook.After that,a limit state equation of the arresting hook system’s reliability was established.For the implicit limit state equation,a surrogate model of the reliability of the arresting hook was established using the Support Vector Machine(SVM)method,and then reliability analysis was carried out using the Monte Carlo method.Finally,it was explained in detail how the key parameters affect the reliability of the hook engaging the arresting cable,and some meaningful conclusions were obtained.This analysis method and its results can provide a reference for the top-level parameter design of carrier-based aircraft and reliability research on the arresting systems.

Antigen-presenting effects of effector memory Vγ9Vδ2 T cells in rheumatoid arthritis

Rheumatoid arthritis is an autoimmune disease that primarily affects the limbs, but the pathogenic mechanism remains unclear. 78 T cells, a T-cell subpopulation, are characterized by multiple biological functions and associated with a variety of diseases. This study investigated the antigen-presenting effects of γδ2 cells and their relationship with rheumatoid arthritis development. We found that Vγ9Vδ2 T cells （the predominant subtype of γδ T cells in peripheral blood） were activated by isopentenyl pyrophosphate to continuously proliferate and differentiate into effector memory cells. The effector memory Vγ9Vδ2 T cells exhibited phenotypic characteristics of specific antigen-presenting cells, including high HLA-DR and CD80/86 expression. These Vγ9Vδ2 T cells could present soluble antigens and synthetic peptides to CD4＋ T cells. Vγ9Vδ2 T cells with different phenotypes showed different cytokine secretion patterns. Effector memoryVγ9Vδ2 T cells simultaneously secreted not only interferon （IFN）-γbut also IL-17. The peripheral blood and joint synovial fluid from RA patients contained numerous heterogeneous γδ T cells that were predominantly effector memory Vγ9Vδ2 T cells with the ability to secrete inflammatory factors. We also found that γδ T cells had a similar antigen-presenting capability to B cells. These results suggest that during the development of rheumatoid arthritis, 78 T cells can aggravate immune dysfunction and produce abnormal immune damage by secreting cytokines and inducing inflammatory cells to participate in synergistic inflammatory responses. Furthermore, γδ T cells can behave similarly to B cells to present viral peptides and autoantigen peptides to CD4＋ T cells, thus sustaining CD4＋ T-cell activation.

Parameter effects on high-speed UAV ground directional stability using bifurcation analysis

A loss of ground directional stability can trigger a high-speed Unmanned Aerial Vehicle(UAV)to veer off the runway.In order to investigate the combined effects of the key structural and operational parameters on the UAV ground directional stability from a global perspective,a fully parameterized mathematical high-speed UAV ground nonlinear dynamic model is developed considering several nonlinear factors.The bifurcation analysis procedure of a UAV ground steering system is introduced,following which the simulation efficiency is greatly improved comparing with the time-domain simulation method.Then the numerical continuation method is employed to investigate the influence of the nose wheel steering angle and the global stability region is obtained.The bifurcation parameter plane is divided into several parts with different stability properties by the saddle nodes and the Hopf bifurcation points.We find that the UAV motion states will never cross the bifurcation curve in the nonlinear system.Also,the dual-parameter bifurcation analyses are presented to give a complete description of the possible steering performance.It is also found that BT bifurcation appears when the UAV initial rectilinear velocity and the tire frictional coefficient vary.In addition,results indicate that the influence of tire frictional coefficient has an opposite trend to the influence of initial rectilinear velocity.Overall,using bifurcation analysis method to identify the parameter regions of a UAV nonlinear ground dynamic system helps to improve the development efficiency and quality during UAV designing phase.

Optimization design containing dimension and buffer parameters of landing legs for reusable landing vehicle

For the landing legs with single air chamber in the buffer structure of the reusable landing vehicle,the geometric topological models and the dynamic model associated with the hard points of the landing legs are established.The geometric constraint relationship in the design of the landing legs is also obtained.The whole vehicle dropping test is conducted,and the test results agree well with that of the simulation model,which validates the dynamic model.Based on the verified model,the effect of hard point positions on the performance of the landing system is analyzed.The multidisciplinary collaborative optimization algorithm and archive-based micro genetic algorithm(CO-AMGA)are used to optimize the design parameters that contain the hard points and the damper.Compared with artificial iteration,the maximum landing impact acceleration response of the vehicle and the buffer struct maximum force are reduced by 30.70%and 14.51%respectively,and the maximum length of retractable pillar decreases by 8.54%while the design margin increases by 69.11%.The proposed optimization method is efficient and can greatly facilitate the design of landing legs.

Bifurcation analysis of dual-sidestay landing gear locking performance considering joint clearance

Sidestay lock mechanism is an important part of landing gear system,and the locking performance can be analyzed based on changes in its stability.However,during numerical continuation analysis of fully-rigid dual-sidestay landing gear without clearance,it has been found that the appearance of bifurcation points does not necessarily imply that both sidestay links can be locked synchronously.This problem reveals the limitations of fully-rigid model with ideally-articulated in solving dual-sidestay mechanisms with extremely high motion sensitivity.Therefore,this study proposes a bifurcation analysis method for synchronous locking of dual-sidestay landing gears,which takes into consideration the joint clearance.For in-depth analysis of this problem,we initially build kinematic and mechanical models of a landing gear mechanism that consider joint clearance.Then,the models are solved based on continuation.The fundamental causes of synchronous locking are discussed in detail,and the number of bifurcation points is found to be closely related to whether the landing gear is completely locked.Finally,the effects of structural parameters on the synchronous locking are analyzed,and the feasible region of parameters satisfying synchronous locking condition is given,which agrees well with the test results.

Study on modal characteristics and vibration reduction of an aircraft rotor–stator brake-induced squeal system

Based on the modal coupling theory,the rotor and stator contact stiffness and axial relative velocity are considered to build an electric aircraft brake dynamic system model in this study.Both the complex modal analysis and transient dynamic analysis methods are used to study the aircraft brake squeal performance and vibratory mechanism.The unstable vibration modes indicate that the out-of-plane vibration plays an important role and the feed-in energy is larger than the output energy in the brake rotor–stator module so that brake squeal takes place.Then the influences of the contact stiffness,friction damping and frictional coefficient on the brake squeal system are carried out,laying the foundation for the three proposed vibration suppression methods.Results show that the coefficient negative-slope condition will intensify the vibration.Also,a linear relationship between the squeal factor and the frictional coefficient is obtained to provide a guidance to predict squeal stability under more conditions.Vibration reduction design shows that adding a damping layer to the brake mechanism and chamfering the edge of braking stators both can reduce brake squeal effectively,while slotting braking stators is invalid in aircraft braking system.

An Exploration in the Potential Substance Basis and Mechanism of Chuanxiong Rhizoma and Angelicae Dahuricae Radix on Analgesia Based on Network Pharmacology and Molecular Docking

Objective:The objective was to study the potential substance basis and action mechanism of Chuanxiong Rhizoma(CX)and Angelicae Dahuricae Radix(AD)on analgesia through network pharmacology and molecular docking.Materials and Methods:The active components and targets of CX and AD and pain-related genes were retrieved through Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform(TCMSP)and GeneCards database.Then,the co-action targets were found,protein–protein interaction network was constructed by the String database.The Cytoscape 3.7.1 was used to construct"CX-AD-active components-pain"network.Further enrichment analysis of Gene Ontology(GO)and Kyoto Encyclopedia of Genes and Genomes(KEGG)was carried out to predict its mechanism of action,the top four active components in the network were docked with the targets.Results:There are 26 compounds,45 targets in the network.Among them,(Z)-ligustilide and beta-sitosterol,respectively,have more potential targets in CX and AD,and prostaglandin-endoperoxide synthase(PTGS2),PTGS1 have more ligands.GO analysis shows that molecular functions of CX and AD mainly performed through the G protein-coupled amine receptor activity,adrenergic receptor activity,and catecholamine binding.KEGG analysis indicates that they could exert analgesic effect on the pathways of regulating neuroactive ligand-receptor interaction,serotonergic synapse,and cGMP-PKG signaling pathway.Molecular docking results show that the active compounds are highly compatible with the structure of the protein receptor,and they interact through the hydrogen bond andπ–πbond between the ligand and the active site residues.Conclusions:Through network pharmacology and molecular docking,this study preliminarily revealed the main active components,targets,and potential regulation network of CX and AD,providing a reference for the subsequent experimental research.