Evaluation of functional outcome and stability of sutureless scleral tunnel fixated IOLs in children with ectopia lentis

AIM:To evaluate functional outcome of sutureless scleral tunnel intraocular lens(SSTIOL)in children with crystalline lens subluxation of more than 7 clock hours.METHODS:A prospective interventional study was conducted consisting of 45 eyes of 44 children in age group 6-18 y having>7 clock hours of lens subluxation who underwent lensectomy-vitrectomy followed by SSTIOL implantation.Primary outcome was improvement in best corrected visual acuity(BCVA)and secondary outcomes were assessment of intraocular lens(IOL)tilt using ultrasound biomicroscopy(UBM),mean change in astigmatism at last follow-up of 1 y and associated complications.RESULTS:The mean preoperative and postoperative BCVA was 1.05±0.28 and 0.64±0.45(log MAR)respectively(P=0.001)at last follow-up.The mean astigmatism preoperatively and postoperatively was-4.17±2.69 D and-1.86±1.25 D respectively(P=0.011).Significant IOL tilt(>5 degrees)was present in 5 cases.The mean percentage endothelial loss was 3.65%±1.92%.The most serious complication encountered was retinal detachment seen in 2 cases.CONCLUSION:SSTIOL implantation provides efficient visual rehabilitation in children provided there is stringent case selection.We recommend caution in children having white-to-white distance>12 mm and presence of peripheral retinal degenerations.

Tunnel personnel positioning method based on TOA and modified location-fingerprint positioning

To position personnel in mines, the study discussed in this paper built on the tunnel personnel positioning method on the basis of both TOA and location-finger print(LFP) positioning. Given non-line of sight(NLOS) time delay in signal transmission caused by facilities and equipment shielding in tunnels and TOA measurement errors in both LFP database data and real-time data, this paper puts forth a database data de-noising algorithm based on distance threshold limitation and modified mean filtering(MMF), as well as a real-time data suppression algorithm based on speed threshold limitation and MMF.On this basis, a nearest neighboring data matching algorithm based on historical location and the speed threshold limitation is used to estimate personnel location and realize accurate personnel positioning.The results from both simulation and the experiment suggest that: compared with the basic LFP positioning method and the method that only suppresses real-time data error, the tunnel personnel positioning methods based on TOA and modified LFP positioning permits effectively eliminating error in TOA measurement, making the measured data close to the true positional data, and dropping the positioning error:the maximal positioning error in measurements from experiment drops by 9 and 3 m, respectively, and the positioning accuracy of 3 m is achievable in the condition used in the experiment.

Upper bound solution for supporting pressure acting on shallow tunnel based on modified tangential technique

Based on the nonlinear failure criterion and the upper bound theorem, the modified tangential technique method was proposed to derive the expression of supporting pressure acting on shallow tunnel. Instead of the same stress state, different normal stresses on element boundaries were used. In order to investigate the influence of different factors on supporting pressures, the failure mechanism was established. The solution of supporting pressure, with different parameters, was obtained by optimization theory. The corresponding failure mechanism and numerical results were presented. In comparison with the results using the single tangential technique method, it is found that the proposed method is effective, and the good agreement shows that the present solution of supporting pressure is reliable.

Sulcus Transscleral Intraocular Lens Suture Fixation through Small Scleral Tunnel Incision

Purpose:To evaluate the clinical efficacy and safety of sulcus transscleral intraocular lens suture fixation with small incision through scleral tunnel in eyes the with posterior capsule defect or insufficient zonula support. Methods:Thirty nine eyes with severe posterior capsule defect and zonula damages caused by small-incision cataract surgery,and those with capsule absence or intraocular lens dislocation were selected in this investigation from February 2007 to December 2009.Sulcus transscleral intraocular lens suture combined with puncture needle-guided external approach and."one- or two-point fixation" method in the small sclera tunnel incision were employed. Results:The mean follow-up was 12.1 months (range from 3 to 28 months). Six eyes were complicated by some eye diseases postoperatively.The best-corrected visual acuity was 20/40 or better in other 34 eyes.(87.17%).All eyes with secondary IOL fixation presented equal or better naked visual acuity than best-corrected visual acuity best-corrected preoperatively.No intraoperative and postoperative complications such as hemorrhage, retinal detachment, intraocular lens tilt and decentration occurred. Conclusion:Sulcus transscleral intraocular lens suture fixation via small sclera tunnel incision was easy to operate and master,required less operative time,and made primary intraocular lens fixation more effective in eyes with posterior capsule defect or insufficient zonula support in small sclera tunnel incision surgery.In addition,the technique was safe and effcacious for secondary intraocular lens fixation.

Influence of modified light dispersion theory on fermion tunneling radiation in the Einstein–Maxwell–dilaton–axion black hole

Based on a light dispersion relationship derived from string theory and quantum gravitational theory,we make an accurate modification to the quantum tunneling radiation rate and black hole temperature at an event horizon in a stationary axial-symmetric Einstein–Maxwell–dilaton–axion black hole.We also analyze our new results and carry out some significant discussions.This work enriches the research content and methods of the frontiers of black hole physics.

Investigation of carbon emission in slurry shield tunnel construction based on modified process analysis method

Underground engineering,including shield tunnel construction,is a significant contributor to carbon dioxide emissions in infrastructure engineering projects.To better predict and control the carbon emissions associated with shield tunnel construction,this paper presents a novel calculation method:the modified process analysis method based on inputoutput and process analysis methods.To evaluate the effectiveness of the proposed method,a specific shield tunnel construction project was selected as a case study.The modified process analysis method was used to analyze the various factors that influence carbon emissions during the project’s construction phase.In addition,a neural network approach was applied to validate the accuracy of the calculation using the LSTM and BP neural network.The results demonstrate that the proposed method not only combines the strengths of traditional methods but also offers high accuracy and acceptable error rates.Based on these findings,several measures to reduce carbon emissions during shield tunnel construction are suggested,providing valuable insights for reducing CO_(2) emissions associated with infrastructure engineering projects.This study highlights the importance of adopting innovative approaches to reduce carbon emissions and promotes the implementation of sustainable practices in the construction industry.Through the use of advanced analytical methods,such as the proposed modified process analysis method,we can effectively mitigate the environmental impact of construction activities and make significant contributions to the global effort to combat climate change.

Three-dimensional pseudo-dynamic reliability analysis of seismic shield tunnel faces combined with sparse polynomial chaos expansion

To address the seismic face stability challenges encountered in urban and subsea tunnel construction,an efficient probabilistic analysis framework for shield tunnel faces under seismic conditions is proposed.Based on the upper-bound theory of limit analysis,an improved three-dimensional discrete deterministic mechanism,accounting for the heterogeneous nature of soil media,is formulated to evaluate seismic face stability.The metamodel of failure probabilistic assessments for seismic tunnel faces is constructed by integrating the sparse polynomial chaos expansion method(SPCE)with the modified pseudo-dynamic approach(MPD).The improved deterministic model is validated by comparing with published literature and numerical simulations results,and the SPCE-MPD metamodel is examined with the traditional MCS method.Based on the SPCE-MPD metamodels,the seismic effects on face failure probability and reliability index are presented and the global sensitivity analysis(GSA)is involved to reflect the influence order of seismic action parameters.Finally,the proposed approach is tested to be effective by a engineering case of the Chengdu outer ring tunnel.The results show that higher uncertainty of seismic response on face stability should be noticed in areas with intense earthquakes and variation of seismic wave velocity has the most profound influence on tunnel face stability.

隧道超挖超耗管控措施研究

隧道的超挖超耗管控是绿色低碳时代背景下工程界最关心的难题,对施工企业的成本控制和效益提升具有重要意义。以武两高速XFS隧道为背景,系统总结了隧道超挖超耗的10类影响因素和常见对策,包括围岩条件、施工参数、测量放样、爆破方案、钻孔质量、喷射混凝土回弹率、预留变形量、物资设备性能、作业人员水平和现场施工管控。分析了XFS隧道超挖超耗的原因,并制定了加强地质预报和超前支护施作,减小开挖进尺;动态调整爆破方案,严格炮孔质量检查;引入超细改性硅微粉优化配合比,提高喷射工艺水平;加强现场施工管控,制定超挖超耗管控办法,落实作业人员的激励奖惩等措施。措施执行后,XFS隧道平均超挖由30.1 cm降低至16.6 cm,综合超耗由173.7%降低至100.7%。

改良膜龈手术在牙龈退缩治疗中的应用

随着人们对美观需求的日益提升,治疗牙龈退缩已经成为牙周科临床常见的患者诉求。临床上主要通过手术的方式治疗牙龈退缩,常见的手术包括游离龈移植术、带蒂瓣技术和双层瓣技术,适应证选择恰当时,通常可以获得满意的效果,但上述术式仍存在一定的不足,如根面覆盖效果不理想等。近年来,学者们针对这些不足陆续提出了一些改良方案来治疗不同程度的牙龈退缩,如改良游离龈移植术,即包含龈乳头及游离龈的牙龈单元移植,可改善受体区血供,提高根面覆盖效果,其针对轻度退缩的部位可获得良好的根面覆盖,同时可增宽角化龈和加深前庭沟,但应用于上颌美学区时可能存在术后牙龈颜色、形态不协调,美学效果欠佳的问题。牙龈瓣采用半厚-全厚-半厚的技术进行制备的改良冠向复位瓣,用于多颗牙牙龈退缩时,以退缩最严重牙为中心的改良切口设计的冠向复位信封瓣技术,可提高根面覆盖效果。不离断龈乳头,使龈瓣形成隧道,以容纳移植物的隧道技术及各种改良的隧道技术,可以有效减少术区的组织损伤,并促进创面愈合。本文通过对各类术式的阐述和文献回顾,总结改良膜龈手术治疗牙龈退缩的临床应用及注意事项,并提出牙龈退缩的治疗方案建议,同时强调牙龈退缩的对因治疗,以达到稳定的根面覆盖效果。创伤小、疗效稳定的手术方式和治疗方法是今后膜龈手术的发展方向。

巩膜隧道法人工晶状体睫状沟缝线固定术的临床观察

目的:观察巩膜隧道法人工晶状体(IOL)睫状沟缝线固定术的临床效果。方法:回顾性分析2021-05/2023-09在我院进行巩膜隧道法IOL睫状沟缝线固定术患者36例38眼的临床资料,术后随访3-26 mo。观察患者术后IOL位置、视力、验光、眼压及并发症情况,评估泪膜破裂时间(BUT)、角膜荧光素钠染色(FL)及基础泪液分泌试验(SⅠt)结果。结果:所有术眼在术后3 mo裸眼视力及最佳矫正视力均较术前改善(均P<0.01)。比较术前,术后1、3 mo的眼表状态数据,BUT及FL评分均有差异(均P<0.05)。术后裂隙灯检查IOL位正,未发生线结暴露情况。结论:巩膜隧道法人工晶状体睫状沟缝线固定术是一种安全、高效、微创的手术方法。

应用异体硬脑膜行改良后巩膜加固术治疗病理性近视的临床效果观察

目的:探讨应用异体硬脑膜行改良后巩膜加固术(PSR)治疗病理性近视(PM)的临床效果。方法:选择2022年1—10月南昌爱尔眼科医院收治30例(33只眼)PM患者,均应用异体硬脑膜行改良PSR治疗。比较治疗前后屈光度(SE)、眼轴长度、视盘与黄斑血流密度、最佳矫正视力(BCVA)、眼压(IOP),并记录术后并发症发生情况。结果:治疗后3个月,SE及黄斑区浅层毛细血管丛(SCP)、深层毛细血管丛(DCP)血流密度均高于治疗前,眼轴长度短于治疗前,差异均有统计学意义(P<0.05)。治疗前、治疗后3个月,BCVA、IOP、视盘内及周围血流密度比较,差异均无统计学意义(P>0.05)。术后短期内30例患者未发生严重并发症,但均出现轻度结膜充血水肿,症状2周后明显缓解,有3例(3只眼)出现轻度视物变形,4例(4只眼)出现一过性眼压升高,使用7 d降眼压滴眼液后均改善。结论:应用异体硬脑膜行改良PSR治疗PM安全可行,改善黄斑区视网膜血流循环,延缓SE、眼轴长度增长。

基于修正Loganathan公式的非水平布置双线平行盾构隧道施工引起土体位移计算方法

[目的]为研究双线平行盾构隧道非水平布置方式下,由施工引起的周围土体位移规律,提出一种基于修正Loganathan公式的土体位移计算方法。[方法]介绍了Loganathan公式及相关假设;考虑盾构隧道开挖扰动引起的地层损失、土体卸荷回弹和土体损失率沿掘进路径变化的综合影响,修正Loganathan公式并建立单线盾构隧道周围土体位移解;建立双线平行盾构隧道非水平布置方式下,由施工引起的土体位移计算方法;通过实际工程的现场监测和数值模拟结果,验证所提计算方法的工程适用性。[结果及结论]所提计算方法能够考虑隧道轴心连线与水平面夹角、双线隧道半径、隧道轴心间距、双线隧道埋深等双线隧道布置因素,以及隧道盾构施工扰动造成的地层损失、土体卸荷回弹和土体损失率沿掘进路径变化等施工因素对土体位移的影响。地面沉降及土体水平位移的理论计算结果同现场监测结果和数值模拟结果之间的平均误差分别为5.6%、0.6%和5.5%、5.3%,均满足工程经验规定的20%的精度要求,说明所提计算方法能够有效解决双线平行盾构隧道非水平布置方式下施工引起的土体位移计算问题,具有良好的工程适用性。

基于上限定理确定隧道式锚碇极限抗拔承载力

隧道式锚碇作为一种新型的悬索桥锚碇结构,因具有因地制宜、经济环保的优点在多山的西南地区得到了广泛应用。已有研究表明,锚塞体围岩性质较差、埋深较浅,锚塞体与围岩接触界面结合程度较好的隧道式锚碇极易发生倒楔形冲切破坏。将破坏体视为以锚塞体中心线为轴线的旋转楔形体,假定破坏面为最小旋转曲面,利用变分法经典欧拉方程求解破坏体最小旋转曲面问题,确定旋转曲面母线方程;基于改进的Mohr-Coulomb强度准则,由主缆拉拔荷载和楔形体自重所做的外功率与楔形体沿滑移面所消耗的内功率相等的条件建立虚功方程,推导隧道式锚碇极限抗拔承载力上限解。开展隧道式锚碇室内模型试验,研究了拉拔承载过程中的坡面位移的变化规律及隧道式锚碇的破坏模式。研究结果表明,拉拔作用点的荷载-位移曲线可分为4个阶段:克服重力阶段、弹性阶段、弹塑性阶段以及破坏阶段;隧道式锚碇破坏模式为围岩倒楔形冲切破坏,破坏体可近似视为以锚塞体中心线为轴线的旋转楔形体;由推导公式得到的隧道式锚碇极限抗拔承载力计算值与实测值一致性较好,具有一定的可靠性,可为隧道式锚碇的设计提供参考。

收敛约束法在挤压性围岩隧道中的应用

由于挤压性围岩隧道围岩性质与应力环境的特殊性,其围岩特征曲线与常规隧道有明显差异。为研究挤压性围岩隧道围岩-支护相互作用关系,考虑支护效应修正围岩特征曲线,研究不同变形等级对修正围岩特征曲线的影响规律,优化挤压性围岩双线铁路隧道初期支护。研究结果表明,毛洞状态下,受双线隧道断面应力集中影响,拱脚和墙脚为安全控制位置;随着变形等级和侧压力系数增加,支护特征曲线与修正围岩特征曲线不再相交;Ⅰ、Ⅱ级变形采用单层支护可满足安全要求,锚杆只需布置在拱部和边墙位置,Ⅱ级及以上变形锚杆需要全环布置;Ⅳ级变形在采用双层支护的同时,需考虑改善洞室形状、超前加固等措施。

改良小切口手术治疗中重度迟发性正中神经麻痹CTS的临床疗效观察

目的探讨分析改良小切口手术松解与传统腕掌部开放手术在治疗中、重度迟发性正中神经麻痹腕管综合征(CTS)的临床疗效观察。方法通过回顾性分析的研究方法,选取2020年1月至2021年2月收治的17例迟发性正中神经麻痹CTS患者作为对照组(传统腕掌部开放手术),选取2021年3月至2022年8月收治的23例迟发性正中神经麻痹CTS患者作为观察组(改良小切口手术松解)进行回顾性临床研究分析。结果两组在一般资料比较上差异无统计学意义(P>0.05),具有可比性。观察组在术后6个月后两点辨别觉距离、疼痛评分、Levine评分、DASH量表评分均优于对照组(P<0.05)。两组术后6个月时肌电图指标CMAP、SNAP、SCV结果较术前均明显升高(P<0.05),且观察组升高幅度优于对照组(P<0.05),两组术后的有效率上,观察组比对照组更具优效性(P<0.05),且观察组的手术时间与对照组相比明显缩短;两组术后腕部柱状痛发生率比较分析,观察组更具优效性(P<0.05),有效率高于对照组。结论与传统腕掌部开放手术治疗中重度迟发性正中神经麻痹CTS比较,改良小切口松解术不仅可以提高临床疗效降低术后并发症,提高临床有效率,还具有优化手术指标、改善正中神经电生理功能、减小腕关节功能损伤等优势。

基于静力推覆试验的4车道公路隧道围岩压力计算模型研究

以典型4车道公路隧道为原型,开展缩尺模型的静力推覆试验,重点关注地层位移、地层裂缝、围岩压力随推覆位移的发展规律,并与2车道隧道的试验结果展开对比。试验结果表明:(1)地层以起拱线为界发生相反方向位移进而产生裂缝,因此计算模型中起裂点位置应由边墙底部修正为起拱线处。(2)地层在推覆作用下沿隧道环向平顺滑移且大角度偏转倾斜,因此计算模型中潜在滑移面应由恒定竖直修正为线性倾斜。在此基础上,探讨了围岩压力计算模型假定在4车道隧道中的适用性,提出适用于4车道公路隧道的围岩压力修正计算模型。研究成果可为4车道公路隧道的抗震计算/验算提供试验依据与技术支撑,为围岩压力计算模型的进一步完善提供参考。

改性水玻璃加固细砂层暗挖隧道现场注浆试验

全断面细砂地层暗挖隧道施工存在塌方失稳的工程风险。本研究通过开展室内试验、现场原位浆液渗透注浆加固试验和现场原位注浆开挖试验,对改性水玻璃浆液在细砂层内部的扩散特征、固砂性能及隧道开挖稳定性开展了一系列工作。结果表明:当改性水玻璃浆液凝结时间控制在1~4 h时,可有效改善低应力条件下粉细砂的抗剪强度,无侧限抗压强度可达到140~170 kPa;在0.3~0.5 MPa注浆压力作用下,改性水玻璃浆液在小导管周边形成了60~80 cm厚的固砂体,有效抑制了砂层塌落,为暗挖隧道的稳定开挖提供保障,现场实测地表变形量控制在25 mm以内;细砂层暗挖隧道超前小导管布孔间距控制在30~50 cm以内,改性水玻璃浆液合理配比宜通过室内试验初选、现场浆液渗透注浆加固试验验证和现场开挖效果反馈等多种手段进行综合确定。

透明角膜切口与巩膜隧道切口白内障超声乳化术治疗年龄相关性白内障的效果及对视力的影响

目的探讨透明角膜切口与巩膜隧道切口白内障超声乳化术治疗年龄相关性白内障的效果及对视力的影响。方法选择88例年龄相关性白内障(单眼)患者作为研究对象,采用随机数字表法分为A组与B组,每组44例。A组采用透明角膜切口白内障超声乳化术治疗,B组采用巩膜隧道切口白内障超声乳化术治疗。对比两组泪膜破裂时间(BUT)、基础泪液分泌量、主观干眼症状评分(SDES)、角膜荧光素钠染色评分,视觉质量和视力恢复情况,术后并发症发生率。结果术后2周时,两组BUT短于本组术前,基础泪液分泌量少于本组术前,SDES评分、角膜荧光素钠染色评分高于本组术前,但B组BUT(7.15±1.74)s长于A组的(3.25±1.85)s,基础泪液分泌量(11.23±3.05)mm/5 min多于A组的(7.15±2.84)mm/5 min,SDES评分(1.39±0.58)分、角膜荧光素钠染色评分(4.15±1.63)分均低于A组的(1.89±0.62)、(6.25±1.32)分(P<0.05)。术后2周时,两组视觉质量评分较本组术前降低,裸眼视力、角膜散光度、最佳矫正视力均较本组术前升高,且B组视觉质量评分(20.15±3.23)分、角膜散光度(1.03±0.61)°低于A组的(31.41±3.84)分、(1.28±0.52)°,裸眼视力(0.82±0.21)、最佳矫正视力(0.46±0.09)均高于A组的(0.63±0.17)、(0.35±0.08)(P<0.05)。A组术后并发症发生率与B组对比无明显差异(P>0.05)。结论巩膜隧道切口白内障超声乳化术治疗年龄相关性白内障更有利于视力恢复,不仅能够减少干眼症与异物感,还能降低角膜散光,且不会增加术后并发症,具有推广价值。

隧道复合式路面层间抗裂性能研究

反射裂缝是隧道复合式路面结构的一大突出问题,严重影响路面使用性能。本文采用加纤改性沥青作为层间抗裂材料,成型了基层预设接缝的复合试件,基于室内弯曲试验和轮碾试验研究其层间抗裂性能,并通过有限元数值分析探究加纤改性沥青对复合式路面沥青面层应力分布情况的影响。结果表明:加纤改性沥青具有良好的层间抗裂性能,能够增强复合试件的抗弯曲能力,减缓反射裂缝的发展,延长复合试件疲劳寿命;有限元分析结果表明加纤改性沥青能够有效吸收沥青面层底部因基层接缝导致的集中应力,大大降低沥青面层底部的最大拉应力和最大剪应力。研究成果可为加纤改性沥青层间抗裂材料在隧道复合式路面中的应用与推广提供理论依据和技术支撑。

城市浅埋隧道埋深对地面沉降的影响规律

[目的]隧道埋深是隧道施工引起地面沉降的重要因素之一,特别是在城市地下空间施工过程中,细微的环境变化极易产生安全隐患。因此,有必要研究城市浅埋隧道的埋深对地面沉降的影响规律。[方法]提出一种关于隧道半径与埋深比的地面沉降理论解二维修正模型;以重庆地区某在建隧道为例,通过模型试验,分析不同埋深条件下地面沉降的变形规律,验证所提修正模型对地面沉降预测的合理性与可行性。[结果及结论]随着隧道埋深的增加,地面沉降总体呈下降趋势,沉降槽的宽度逐渐增大,隧道轴线上的最大沉降量逐渐减小;相较于原理论解及Peck公式解,修正后的沉降预测模型与试验值所得曲线较为接近,且修正模型在不同隧道埋深条件下具有更好的适用性;在浅埋隧道施工过程中,当隧道埋深增加时,建议扩大控制保护区的范围。