Effect of femtosecond and microkeratome flaps creation on the cornea biomechanics during laser in situ keratomileusis： one year follow-up

AIM： To compare the corneal biomechanical outcomes at one year after laser in situ keratomileusis（LASIK） with the flaps created by Ziemer and Moria M2 microkeratome with 110 head and -20 blade.METHODS： Totally 100 eyes of 50 consecutive patients were enrolled in this prospective study and divided into two groups for corneal flaps created by Ziemer Femto LDV and Moria M2 microkeratome with 110 head and -20 blade.Corneal biomechanical properties including cornea resistance factor（CRF） and cornea hysteresis（CH） were measured before and 1,3,6,12 mo after surgery by ocular response analyzer.Central cornea thickness and corneal flap thickness were measured by optical coherence tomography.RESULTS： The ablation depth（P=0.693）,residual corneal thickness（P=0.453）,and postoperative corneal curvature（P=0.264） were not significant different between Ziemer group and Moria 110-20 group after surgery.The residual stromal bed thickness,corneal flap thickness,CH and CRF at 12 mo after surgery were significant different between Ziemer group and Moria 110-20 group（P〈0.01）; Ziemer group gained better corneal biomechanical results.The CRF and CH increased gradually from 1 to12 mo after surgery in Ziemer group,increased from 1 to 6 mo but decreased from 6 to 12 mo in Moria 110-20 group.Both CRF and CH at one year after surgery increased with the increasing of residual cornea thickness; pre-LASIK CRF,CRF also increased with residual stromal bed thickness,while CH decreased with the increasing of pre-LASIK intraocular pressure and cornea flap thickness（P〈0.01）.CONCLUSION： In one year follow-up,femtosecond laser can provide better cornea flaps with stable cornea biomechanics than mechanical microkeratome.

基于VTI介质海洋CSEM和MT数据联合反演的黄海海相残留盆地深部结构研究

黄海海相残留盆地因其地层结构和深部地质构造的复杂性,一直是我国海洋地球科学的一项研究重点,虽然针对该研究区已开展了一系列的地球物理调查,但由于高速碳酸盐岩层对地震波存在着一定的屏蔽作用,致使该海域深部地震资料品质受到较大影响.海洋电磁法不受高速屏蔽层影响,有利于获得高速屏蔽层内部及其下方的深部结构信息.海洋可控源电磁法(Controlled source electromagnetic method,CSEM)和海洋大地电磁测深(Magnetotelleric,MT)能够提供海底电性结构的互补信息,较于单一的电磁方法,二者联合可获得更为准确的海底电性分布.本文提出了基于乘积目标函数的层状垂直各向异性(Vertical anisotropic,VTI)介质海洋可控源电磁和大地电磁资料联合反演方法,该方法在迭代过程中根据数据的拟合情况自适应调整CSEM和MT数据的权重和正则化因子的权重,反演参数包括海底介质的横向电阻率、垂向电阻率和地层厚度.以南黄海地质地球物理资料为例,建立浅水环境地电模型,并结合浅水环境的高噪声背景特点进行合成数据模型测试及分析.将本文所提出算法应用于理论模型合成数据和南黄海实测资料反演,结果表明,较于单独的海洋CSEM和MT反演,联合反演方法能够较准确地重构海底地层的电性分布,提高对海底地层各向异性电阻率的分辨能力.

Pregnancy-Induced Changes in Ocular Biomechanics Are Related to Maternal Hormone Levels in Healthy Chinese Pregnant Women

Background: To explore the changes in ocular biomechanics during pregnancy and the postpartum period and their association with maternal hormone level changes. Methods: In a prospective cohort study, 24 eyes of 12 pregnant women were enrolled and monitored throughout pregnancy and after delivery (6 weeks). Intraocular pressure (IOP), central corneal thickness (CCT), corneal endothelium cell (CEC), axial length (AL), corneal curvature (K1, K2), anterior chamber depth (ACD), central subfield thickness (CST), macular volume (MV), cube average thickness (CAT), retinal nerve fibre layer (RNFL), tear meniscus height (TMH), and breaking up time (BUT) were measured throughout pregnancy, and blood plasma levels of maternal hormones were determined at the same time points. Results: A gradual decrease in IOP values was observed as gestation progressed, and there was a statistically significant difference in IOP between the 3rd trimester and the 1st and 2nd trimester and postpartum (p = 0.002, p = 0.006, p = 0.050). There was a significant difference between the 1st and 2nd trimesters in terms of MV (p = 0.023). The difference in RNFL in the 3rd trimester and postpartum was significant (p = 0.011). The levels of the β-hCG showed a significant correlation with K2, ACD, and TMH only in the 2nd trimester (r = 0.588, p = 0.045;r = - 0.740, p = 0.006;r = 0.642, p = 0.024). Regarding luteinizing hormone, there was a negative correlation with MV in the 1st and 2nd trimesters (r = - 0.598, p = 0.040;r = - 0.672, p = 0.017) and CAT in the 1st and 2nd trimesters (r = - 0.599, p = 0.040;r = - 0.655, p = 0.021). Luteinizing hormone levels were correlated with ACD (r = - 0.702, p = 0.011) in the 2nd trimester and K2 (r = 0.585, p = 0.046) in the 3rd trimester. A correlation was found between follicle-stimulating hormone levels and CEC, MV and CAT in the 1st trimester (r = - 0.677, p = 0.016;r = - 0.602, p = 0.039;r = - 0.584, p = 0.046) and AL in the 3rd trimester (r = - 0.618, p = 0.032). The correlation between oestradiol and CST in the 1st trimester (r = - 0.621, p = 0.031) and RNFL (r = 0.594, p = 0.041) in the postpartum. A statistically significant correlation between progesterone and MV (r = 0.583, p = 0.047) and TMH (r = 0.762, p = 0.004) was observed in the 1st trimester. No significant intergroup correlation was observed postpartum (p > 0.05). Conclusion: Ophthalmological parameters showed physiological changes induced by hormone levels in pregnancy and returned to baseline levels after delivery.

基于调车工况的MT-2缓冲器容量需求仿真分析

为了分析MT-2缓冲器在调车连挂作业时的容量需求问题,基于摩擦式缓冲器非线性力学特性及车辆调车冲击受力特点,建立了铁道货车纵向冲击动力学模型,对调车过程中不同车辆质量、不同速度、不同编组方式及不同车体刚度等工况下MT-2缓冲器容量需求进行了分析。研究结果表明:缓冲器做功与车辆质量和连挂速度的平方成正比,冲击车和被冲击车数量都大于2辆时冲击面缓冲器的容量需求将与车辆数量无关。对同时考虑质量、速度、编组方式、车体刚度的缓冲器容量需求值进行了函数拟合,完成了比例系数κ、μ和λ的求解;不同车辆数量之间冲击时,不同车钩号的缓冲器做功值大小不一,在冲击面车钩号的缓冲器做功值均为最大,沿着冲击面前、后的车钩号逐渐递减,调车冲击时计算容量需求值时应不考虑车体刚度,以重车冲击重车模式时冲击面的缓冲器容量需求为准。

Changes in corneal biomechanics and posterior corneal surface elevation after FS-LASIK

AIM:To investigate the changes in corneal biomechanics and posterior corneal surface elevation after femtosecond laser-assisted in situ keratomileusis(FS-LASIK).METHODS:Totally 197 eyes of 100 patients who underwent the FS-LASIK from April 2022 to November 2022 were included.They were divided into three groups according to the ratio of residual corneal stroma thickness/corneal thickness(RCST/CT):Group I(50%≤RCST/CT<55%,63 eyes of 32 patients),Group II(55%≤RCST/CT<60%,67 eyes of 34 patients),and Group III(RCST/CT≥60%,67 eyes of 34 patients).The intraocular pressure(IOP),corneal compensated IOP(IOPcc),corneal hysteresis(CH)and corneal resistance factor(CRF)were measured immediately,1,and 3mo postoperatively by ocular response analyzer(ORA)and the posterior elevation difference(PED)was measured by Pentacam.RESULTS:After operation,IOP,CH,CRF,and PED were statistically different among the three groups(F=12.99,31.148,23.998,all P<0.0001).There was no statistically significant difference in IOPcc among the three groups(F=0.603,P>0.05).The IOP,IOPcc,CH,and CRF were statistical changed after surgery(F=699.635,104.125,308.474,640.145,all P<0.0001).The PED of Group I was significantly higher than that of Group II(P<0.05),and Group II was significantly higher than that of Group III(P<0.05).The PED value of 3mo after surgery decreased in each group compared with 1mo after surgery,but there was no statistical difference(Group I:t=0.82,P=0.41;Group II:t=0.17,P=0.87;Group III:t=1.35,P=0.18).The correlation analysis of corneal biomechanical parameter changes with PED at 1mo and 3mo after surgery showed thatΔIOP,ΔIOPcc,ΔCH,andΔCRF were not correlated with PED value in three groups(P>0.05).CONCLUSION:The smaller the RCST/CT,the greater effect on corneal biomechanics and posterior surface elevation.There is no correlation between changes in corneal biomechanics and posterior corneal surface elevation in the range of RCST/CT≥50%.

Changes in corneal biomechanics and intraocular pressure following Femto-LASIK using Goldman applanation tonometry and ocular response analyzer

AIM:To compare intraocular pressure(IOP)measurements before and after laser in situ keratomileusis(LASIK)with a femtosecond laser for flap creation using ocular response analyzer(ORA)and Goldmann applanation tonometry,and to identify factors that may influence the preoperative and postoperative IOP.METHODS:A prospective study conducted on myopic patients who underwent LASIK using a femtosecond laser for flap fashioning.Enrolled patients were evaluated preoperatively,6 wk and 3 mo postoperatively for manifest refraction(MR),keratometric(K)readings and central corneal thickness(CCT)using a scheimpflug-based topography.Corneal resistance factor(CRF),corneal hysteresis(CH),Goldmann correlated IOP(IOPg)and corneal compensated IOP(IOPcc)were measured using ORA besides IOP assessment by Goldman applanation tonometry(GAT).RESULTS:There was a statistically significant decrease in measures of IOPg by 3.35±0.83 mm Hg,followed by GAT which decreased by 2.2±0.44 mm Hg,and the least affected by operation was IOPcc which decreased only by 0.87±0.1 mm Hg after 6 wk.After 3 mo follow up there was a statistically significant decrease in IOPcc which decreased only by 0.76±0.4 mm Hg,followed by IOP GAT by 1.6±0.5 mm Hg,and the most affected by operation was IOPg which decreased by 2.3±0.3 mm Hg.Correspondingly,there was a statistically significant decrease in CH and CRF after 6 wk and 3 mo.At 3 mo,the preoperative MR and preoperative GAT were prominent significant predictors of the postoperative GAT changes.The prediction equation was subsumed.CONCLUSION:IOP measurements and corneal biomechanical factors reduce significantly after LASIK with a femtosecond laser for flap creation.The IOPcc values are less influenced by changes in corneal properties than IOPg and GAT,indicating that IOPcc may provide the most reliable measurement of IOP after this procedure.

基于MT7620A的智慧监控网关设计

针对网络摄像机不具备远程监控能力的问题,基于MT7620A设计了一种支持远程监控的智慧网关。网关使用MT7620A作为主控芯片,搭载OpenWrt系统。通过创建ONVIF客户端与同一局域网中支持ONVIF协议的监控设备进行通信,实现设备发现、信息获取、云台控制和视频流读取等功能;网关与云平台通过MQTT协议实现信令交互,云平台可以向网关发送设备管理、云台控制和视频流读取等命令;网关通过数据处理模块对命令进行解析和协议转换,实现对设备的管理,以及对监控设备云台的控制和视频流读取。网关在使用FFMPEG接口获取视频流之后,通过Socket TCP与云平台建立连接并发送视频流,保证视频流远程传输的稳定可靠。网关配有4G通信模块,避免了接入互联网受到有线网络通信的限制,双重通信方式更加有效地保障了网络传输。测试结果表明,所设计的网关能够支持云平台实现对设备的远程监控和控制。

Effect of cervical spine surgery on the biomechanics of the cervical spine

In clinical practice,cervical spine surgery inevitably alters the original physiological structure of the cervical spine,thus causing changes in the original biomechanical properties of the cervical spine.The biomechanical properties of the cervical spine are particularly significant as it is an essential structure that supports the head and connects the trunk.Different cervical spine surgery options can have different effects on the biomechanics of the cervical spine.Therefore,this review will discuss recent research advances on the effects of cervical spine surgery on cervical spine biomechanics.We hope that this review will provide some theoretical basis for future studies on the biomechanical effects of cervical spine surgery on the cervical spine.

CSAMT、MT等电磁法在矿山地质勘探中技术参数研究

目前,在矿山地质勘探中广泛采用CSAMT、MT等电磁法,但该类电磁法均存在电磁干扰影响因素,都存在其所对应地质条件的最佳工作技术参数,为了降低野外数据采集工作过程中电磁干扰并达到最佳工作目标任务要求,本文通过作者十几年来积累的关于CSAMT、MT在各种不同矿山地质条件下的工作经验及试验结论,总结得出该类电磁法在一定地质条件下的最佳工作技术参数,将为今后在不同矿山、不同地质条件下开展该相关方法提供参考示范。

养殖水域Cu^(2+)胁迫对虹鳟MT2基因表达模式的影响

为了探究水体中铜离子胁迫对虹鳟(Oncorhynchus mykiss)MT2基因表达模式的影响,开发Metallothioneins作为检测水域生态中重金属铜污染的分子标志,该研究利用TA克隆法获得了虹鳟MT2基因的CDS序列,检测了MT2基因在虹鳟不同组织中的表达模式,以及Cu^(2+)胁迫(Cu^(2+)浓度75、150和300μg/L)后1、2、3和4 d和胁迫恢复1、2 d时间点的MT2基因表达动态。结果表明,虹鳟MT2基因CDS区长186 bp,编码62个氨基酸,具有典型的半胱氨酸(Cys)-X(1~3个)-半胱氨酸结构,属不稳定亲水性蛋白。虹鳟MT2基因序列与大西洋鲑的同源性最高且在肝脏中表达量最高,其次是脑和肠道。胁迫试验结果显示,MT2基因在肝脏和鳃中呈现先升高后降低的趋势,在头肾、脾脏和脑中呈现逐渐升高的趋势,且呈现一定的剂量依赖性,肠道MT2基因在胁迫2、3和4 d被显著抑制。胁迫恢复后,处理组肝脏、头肾、鳃、脑MT2基因表达量仍显著升高。综上,虹鳟MT2基因能在不同组织中被Cu^(2+)诱导表达,推测MT2基因在虹鳟抗重金属毒性中可能发挥着重要作用,且MT2基因表达量与铜离子的浓度相关,可以作为分子生物标志检测水域生态中的重金属铜污染。

Assessment of sediment connectivity using modelling and field-based approaches in the Slavíč River catchment(MoravskoslezskéBeskydy Mts,Czech Republic)

Mountain streams act as conveyors of sediments within the river continuum,where the physical transport of sediments between river reaches through the catchment or between individual parts(e.g.,between hillslopes and channels)of the catchment is assumed.This study focused on sediment connectivity analysis in the SlavíčRiver catchment in the MoravskoslezskéBeskydy Mts in the eastern part of the Czech Republic.The connectivity index and connectivity index target modelling were combined with an analysis of anthropogenic interventions.Additionally,field mapping,grain size of bed sediments and stream power analysis were used to obtain information about connectivity in the catchment.Based on the analysis and obtained results,terrain topography is the current main driving factor affecting the connectivity of sediment movement in the SlavíčRiver catchment.However,the modelling provided valuable information about high sediment connectivity despite different recent land use conditions(highly forested area of the catchment)than those in historical times from the 16th to 19th centuries when the SlavíčRiver catchment was highly deforested and sediment connectivity was probably higher.The analysis of anthropogenic interventions,field mapping,grain size of bed sediments and stream power analysis revealed more deceleration of sediment movement through the catchment,decreased sediment connectivity with bed erosion,and gradual river channel process transformation in some reaches.Field mapping has identified various natural formations and human-induced changes impacting the longitudinal and lateral connectivity in the SlavíčRiver.For instance,embankments along 48%of the river's length,both on the right and left banks,significantly hinder lateral sediment supply to the channel.Stream power index analysis indicates increased energy levels in the flowing water in the river's upper reaches(up to 404.8 W m^(-2)).This high energy is also observed in certain downstream sections(up to 337.6 W m^(-2)),where it is influenced by human activities.These conditions lead to intensified erosion processes,playing a crucial role in sediment connectivity.Similar observations were described in recent studies that pointed out the long-term human interventions on many streams draining European mountains,where a decrease in sediment connectivity in these streams is linked with sediment deficits and the transformation of processes forming channels.

基于MT-CNN的矿井带式输送机输煤量检测技术

为实现矿井带式输送机输煤量检测的信息化、智能化,提出基于MT-CNN的矿井带式输送机输煤量检测技术。为了全面提升输煤量检测技术,从而提高矿井效益,选取了多任务卷积神经网络(MT-CNN)对检测目标进行多核心识别检测,优化了图像直线信息和边缘信息的提取效率,构建了良好的网络层次结构,优化了信息连接通道,从而全面提高图像识别分析和数据检测处理的效果。通过MT-CNN技术对输煤量的轮廓形态和荷载状态进行分析运算,经过图像样本数据训练获取矿井带式输送机输煤量的相关数据。研究结果表明,该技术能够有效提高输煤量图像识别的真实性,而检测时间缩短49%,计算结果准确率提高到98%,有效提高了输煤量检测的效率和准确度,具有较好的应用性能和良好的使用效果。加强矿井带式输送机的输煤量检测,可以为后续研究提供依据,很大程度上推动了相关技术发展,实现矿井信息化、智能化、现代化发展。

MTS-05 PDM多频代播机核心技术及应用

深入探讨MTS-05 PDM 5 kW多频代播机的研发背景、核心技术、应用价值及其对广播技术领域的影响。在中波广播技术面临频率固定性和调频机制局限的挑战背景下,MTS-05 PDM 5 kW多频代播机作为技术创新的产物,通过集成复杂可编程逻辑器件(Complex Programmable Logic Device,CPLD)逻辑频率选通技术、直接数字合成(Direct Digital Synthesizer,DDS)高频激励机制和智能多频网络切换技术,实现了多频次高效、安全播出。设备不仅克服了传统发射机的调频烦琐和空间限制问题,还提升了播出质量和安全播出效率,展示了智能化运维与资源优化的典范。

基于大地测量和MT技术分析吉林龙岗火山区现今地壳运动特征及其机理

位于吉林长白山西麓龙岗山脉中段的龙岗火山群是中国近代主要火山活动区之一.通过对火山区2010—2020年多期GNSS(Global Navigation Satallite System)观测资料及1970—2010年多个时段的一、二等水准资料进行解算,获取现今三维地壳运动速度场.GNSS获取的水平运动速率从西向东增大,东部主要以拉张运动为主,连续面应变率场结果反映火山区位于膨胀区;一等水准路线长抚线和丹抚线资料显示火山区以垂直上升运动为主,主要速率为0.55~1.83 mm/a,其中抚松—仙人桥—老山队一带为主要隆升区,速率多大于1.0 mm/a;该区域分布丰富的地热资源,也是地震多发地区.邻近区域的二等水准路线梅通线速率相对较小,为0.23~0.77 mm/a.结合对99个测点大地电磁数据三维反演得到的火山区深部电性结构:与隆升区对应的中下地壳赋存相对较浅的岩浆系统,电性边界带推测的浑江断裂北向延伸.断裂附近的低阻体规模最大,向下延伸至地幔尺度.最浅的低阻体位于最年轻的金龙顶子火山大约10 km以下位置,以上的高阻结构认为是岩浆溢流结束后的后撤和固结.综合分析认为现今火山区地壳的膨胀隆升、地震活动与幔源物质的上涌、间断性的运移引起断层活动有关.

求解无人驾驶车辆路径规划问题的QPC-MT-RRT算法

针对无人驾驶车辆路径规划问题,基于快速扩展随机树(rapidly-exploring random tree,RRT)算法,提出了1种5次多项式曲线(quintic polynomial curve)与MT-RRT(multi-targeting rapidly-exploring random tree)的融合算法,即QPC-MT-RRT算法。该算法根据无人驾驶车辆路径规划的相关理论,建立无人驾驶车辆路径规划问题的车辆运动学模型,为规划无人驾驶车辆最优、最高效、最安全路径提供理论依据。将上述算法在MATLAB上仿真,并在平均路径长度、平均路径规划时间、平均采样节点个数及节点利用率4个方面与基本RRT算法及MT-RRT算法进行了对比。仿真结果表明:5次多项式曲线与MT-RRT算法的融合算法具有最高的性能,可以规划出最优路径。

Micro air vehicle-motivated computational biomechanics in bio-flights:aerodynamics,flight dynamics and maneuvering stability

Aiming at developing an effective tool to unveil key mechanisms in bio-flight as well as to provide guidelines for bio-inspired micro air vehicles（MAVs） design,we propose a comprehensive computational framework,which integrates aerodynamics,flight dynamics,vehicle stability and maneuverability.This framework consists of（1） a Navier-Stokes unsteady aerodynamic model;（2） a linear finite element model for structural dynamics;（3） a fluidstructure interaction（FSI） model for coupled flexible wing aerodynamics aeroelasticity;（4） a free-flying rigid body dynamic（RBD） model utilizing the Newtonian-Euler equations of 6DoF motion;and（5） flight simulator accounting for realistic wing-body morphology,flapping-wing and body kinematics,and a coupling model accounting for the nonlinear 6DoF flight dynamics and stability of insect flapping flight.Results are presented based on hovering aerodynamics with rigid and flexible wings of hawkmoth and fruitfly.The present approach can support systematic analyses of bio- and bio-inspired flight.

Biomechanics of the anterior cruciate ligament:Physiology,rupture and reconstruction techniques

The influences and mechanisms of the physiology,rupture and reconstruction of the anterior cruciate ligament(ACL)on kinematics and clinical outcomes have been investigated in many biomechanical and clinical studies over the last several decades.The knee is a complex joint with shifting contact points,pressures and axes that are affected when a ligament is injured.The ACL,as one of the intra-articular ligaments,has a strong influence on the resulting kinematics.Often,other meniscal or ligamentous injuries accompany ACL ruptures and further deteriorate the resulting kinematics and clinical outcomes.Knowing the surgical options,anatomic relations and current evidence to restore ACL function and considering the influence of concomitant injuries on resulting kinematics to restore full function can together help to achieve an optimal outcome.

Optimal Design of Bicycle Frame Parameters Considering Biomechanics

With the development of technology and the change of market demands,the trend in middle and high grade bicycle manufacturing is developed toward small-volume,multi-species,and customer-oriented production.Therefore,human element should be fully considered in design so that the bicycle has the best cycling performance for the specific rider.Currently,customized design is difficult to achieve since feature parameters of the rider are not included in the design.The design of bicycle frame is the most important in bicycle design.The relative positions among the saddle,handlebar and central axis are defined as the bicycle three-pivot,they are the main parameters in bicycle frame design.In conventional bicycle design,frame parameters are merely relevant to bicycle types.On the basis of the principles of biomechanics and ergonomics knowledge,this paper presents a design method for bicycle three-pivot considering feature parameters of the rider by dynamic simulation.Firstly,a dynamic model of rider-bicycle system is built for a special rider,and a serial of simulation experiments is designed by uniform test method.Then,a mathematical model is built between the three-pivot position and the square of lower limb muscle stress by using simulation and regression analysis of the rider-bicycle system.The optimal three-pivot position parameters are obtained by setting the minimal of the square of the lower limb muscle stress as the objective.Therefore,the optimal parameters are gained for the specific rider.Finally,various results are gained for different riders based on the same design process.The function between feature parameters of the rider and the optimum three-pivot position parameters is built by regression.Bicycle design considering biomechanics can be divided into three main steps：calculating the three-pivot position,designing the geometrical structure of the bicycle frame and analyzing frame strength,and selecting appropriate parts and assembling the bicycle.Bicycle design considering biomechanics changes the conventional bicycle design and realizes customized design by considering human element in the design process.

Acellular allogeneic nerve grafting combined with bone marrow mesenchymal stem cell transplantation for the repair of long-segment sciatic nerve defects:biomechanics and validation of mathematical models

We hypothesized that a chemically extracted acellular allogeneic nerve graft used in combination with bone marrow mesenchymal stem cell transplantation would be an effective treatment for long-segment sciatic nerve defects.To test this,we established rabbit models of 30 mm sciatic nerve defects,and treated them using either an autograft or a chemically decellularized allogeneic nerve graft with or without simultaneous transplantation of bone marrow mesenchymal stem cells.We compared the tensile properties,electrophysiological function and morphology of the damaged nerve in each group.Sciatic nerves repaired by the allogeneic nerve graft combined with stem cell transplantation showed better recovery than those repaired by the acellular allogeneic nerve graft alone,and produced similar results to those observed with the autograft.These findings confirm that a chemically extracted acellular allogeneic nerve graft combined with transplantation of bone marrow mesenchymal stem cells is an effective method of repairing long-segment sciatic nerve defects.

Biomechanics of sclera crosslinked using genipin in rabbit

AIM：To strengthen the biomechanics of collagen by crosslinking rabbit scleral collagen with genipin to develop a new therapy for preventing myopic progression. METHODS：Ten New Zealand rabbits were treated with 0.5 mmol/L genipin injected into the sub-Tenon＇s capsule in the right eyes. Untreated contralateral eyes served as the control. The treated area was cut into scleral strips measuring 4.0 mm×10.0 mm for stress-strain measurements（n=5）. The remaining five treated eyes were prepared for histological examination.RESULTS：Compared to the untreated scleral strips,the genipin-crosslinked scleral strips showed that the ultimate stress and Young＇s modulus at 10% strain were increased by the amplitude of 130% and 303% respectively,ultimate strain was decreased by 24%. There had no α-smooth muscle actin（α-SMA）positive cells in control and treated sclera. Histologically,there was no sign of apoptosis in the sclera,choroid,and retina; and no side effects were found in the peripheral cornea and optic nerve adjacent to the treatment area.CONCLUSION：Genipin induced crosslinking of collagen can increase its biomechanical behavior by direct strengthening of the extracellular matrix in rabbit sclera,with no α-SMA expression seen in the myofibroblasts. As there is no evidence of cytotoxicity in the scleral,choroidal,and retinal cells,genipin is likely a promising agent to strengthen the weakened sclera to prevent myopic progression.