Disorganization of the retinal inner layers as a predictor of visual acuity in eyes with macular edema secondary to uveitis

AIM:To assess the correlation between disorganization of the retinal inner layers(DRIL)and best-corrected visual acuity(BCVA)in patients with uveitis and macular edema(UME)who underwent systemic treatment using optical coherence tomography(OCT).METHODS:A retrospective clinical study of 23 patients(30 eyes)with DRIL and 23 patients(31 eyes)without DRIL secondary to UME were included.All patients underwent comprehensive ophthalmic examinations at baseline,3,6,and 12 mo after local and systemic treatment.The OCTbased parameters included foveal center point thickness(FCPT),mean thickness(MT),and diameters of DRIL in horizontal and vertical directions.BCVA and OCT-based parameters were compared between the two groups.The relationship between each OCT parameter and BCVA was evaluated using linear correlation and regression analysis.RESULTS:At the initial visit,the mean baseline FCPT was 441.03±128.68μm in the eyes with DRIL and 337.26±99.31μm in the eyes without DRIL(P=0.001).No significant differences were observed in MT(P=0.357).The mean size of transverse and vertical diameters of DRIL was 684.07±267.51 and 267.07±104.61μm at baseline,respectively.There was significant improvement in BCVA and OCT-based parameters at 3,6,and 12 mo in all cases(P<0.001 for each timepoint).In addition,significant differences were detected in BCVA and OCT parameters between eyes with and without DRIL at each time point(P<0.01 for each timepoint).A greater DRIL range at baseline was associated with a worse baseline BCVA(transverse diameter of DRIL:r=0.875,P<0.001;vertical diameter of DRIL:r=0.622,P<0.001).The transverse diameter of baseline DRIL was found to be significantly correlated with the final BCVA(P=0.003).CONCLUSION:The improvement in BCVA is associated with DRIL in patients with UME.DRIL is an easy-todetermine and robust imaging biomarker that could help predict BCVA prognosis in eyes with UME.

Characterization of inner layer thickness change of a composite circular tube using nonlinear circumferential guided wave:A feasibility study

The feasibility of using the nonlinear effect of primary circumferential guided wave(CGW)propagation for characterizing the change of inner layer thickness of a composite circular tube(CCT)has been investigated.An appropriate mode pair of the fundamental and double-frequency CGWs(DFCGWs)has been selected to enable the second harmonics of primary wave mode in the given CCT to accumulate along the circumferential direction.When changes in the inner layer thickness(described as the equivalent inner layer thickness)take place,the corresponding nonlinear CGW measurements are conducted.It is found that there is a direct correlation between change of equivalent inner layer thickness of the CCT and the relative acoustic nonlinearity parameter(Δβ)measured with CGWs propagating through one full circumference,and that the effect of second-harmonic generation(SHG)is very sensitive to change in the inner layer thickness.The experimental result obtained demonstrates the feasibility for quantitatively assessing the change of equivalent inner layer thickness in CCTs using the effect of SHG by primary CGW propagation.

Response features of nonlinear circumferential guided wave on early damage in inner layer of a composite circular tube

A theoretical model to analyze the nonlinear circumferential guided wave(CGW) propagation in a composite circular tube(CCT) is established. The response features of nonlinear CGWs to early damage [denoted by variations in third-order elastic constants(TOECs)] in an inner layer of CCT are investigated. On the basis of the modal expansion approach, the second-harmonic field of primary CGW propagation can be assumed to be a linear sum of a series of double-frequency CGW(DFCGW) modes. The quantitative relationship of DFCGW mode versus the relative changes in the inner layer TOECs is then investigated. It is found that the changes in the inner layer TOECs of CCT will obviously affect the driving source of DFCGW mode and its modal expansion coefficient, which is intrinsically able to influence the efficiency of cumulative second-harmonic generation(SHG) by primary CGW propagation. Theoretical analyses and numerical simulations demonstrate that the second harmonic of primary CGW is monotonic and very sensitive to the changes in the inner layer TOECs of CCT, while the linear properties of primary CGW propagation almost remain unchanged. Our results provide a potential application for accurately characterizing the level of early damage in the inner layer of CCT through the efficiency of cumulative SHG by primary CGW propagation.

Discriminating performance of macular ganglion cellinner plexiform layer thicknesses at different stages of glaucoma

AIM: To determine the discriminating performance of the macular ganglion cell-inner plexiform layer(GCIPL) parameters between all the consecutive stages of glaucoma(from healthy to moderate-to-severe glaucoma), and to compare it with the discriminating performances of the peripapillary retinal nerve fiber layer(RNFL) parameters and optic nerve head(ONH) parameters.METHODS: Totally 147 eyes(40 healthy, 40 glaucoma suspects, 40 early glaucoma, and 27 moderate-to-severe glaucoma) of 133 subjects were included. Optical coherence tomography(OCT) was obtained using Cirrus HD-OCT 5000. The diagnostic performances of GC-IPL, RNFL, and ONH parameters were evaluated by determining the area under the curve(AUC) of the receiver operating characteristics. RESULTS: All GC-IPL parameters discriminated glaucoma suspect patients from subjects with healthy eyes and moderate-to-severe glaucoma from early glaucoma patients(P<0.017, for all). Also, minimum, inferotemporal and inferonasal GC-IPL parameters discriminated early glaucoma patients from glaucoma suspects, whereas no RNFL or ONH parameter could discriminate between the two. The best parameters to discriminate glaucoma suspects from subjects with healthy eyes were superonasal GC-IPL, superior RNFL and average c/d ratio(AUC=0.746, 0.810 and 0.746, respectively). Discriminating performances of all the parameters for early glaucoma vs glaucoma suspect comparison were lower than that of the other consecutive group comparisons, with the bestGC-IPL parameters being minimum and inferotemporal(AUC=0.669 and 0.662, respectively). Moreover, minimum GC-IPL, average RNFL, and rim area(AUC=0.900, 0.858, 0.768, respectively) were the best parameters for discriminating moderate-to-severe glaucoma patients from early glaucoma patients.CONCLUSION: GC-IPL parameters can discriminate glaucoma suspect patients from subjects with healthy eyes, and also all the consecutive stages of glaucoma from each other(from glaucoma suspect to moderate-tosevere glaucoma). Further, the discriminating performance of GC-IPL thicknesses is comparable to that.

Retinal nerve fiber layer and ganglion cell-inner plexiform layer thickness in children with obesity

AIM：To evaluate retinal nerve fiber layer（RNFL）thickness analysis of peripapillary optic nerve head（PONH） and macula as well as ganglion cell-inner plexiform layer（GCIPL） thickness in obese children.· METHODS：Eighty-five children with obesity and 30 controls were included in the study.The thicknesses of the PONH and macula of each subject＇s right eye were measured by high-resolution spectral-domain optic coherence tomography（OCT）.· RESULTS：The RNFL thicknesses of central macular and PONH were similar between the groups（all P 〉0.05）.The GCIPL thickness was also similar between the groups.However,the RNFL thickness of temporal outer macula were 261.7±13.7 and 268.9±14.3 μm for the obesity and the control group,respectively（P =0.034）.· CONCLUSION：Obesity may cause a reduction in temporal outer macular RNFL thickness.

Comparisons of ganglion cell-inner plexiform layer loss patterns and its diagnostic performance between normal tension glaucoma and primary open angle glaucoma: a detailed, severity-based study

AIM: To evaluate the patterns of macular ganglion cell-inner plexiform layer(GCIPL) loss in normal tension glaucoma(NTG) and primary open angle glaucoma(POAG) in a detailed, disease severity-matched way;and to assess the diagnostic capabilities of GCIPL thickness parameters in discriminating NTG or POAG from normal subjects.METHODS: A total of 157 eyes of 157 subjects, including 57 normal eyes, 51 eyes with POAG and 49 eyes with NTG were enrolled and strictly matched in age, refraction, and disease severity between POAG and NTG groups. The average, minimum, superotemporal, superior, superonasal, inferonasal, inferior, and inferotemporal GCIPL thickness, and the average, superior, temporal, inferior, and nasal retinal nerve fiber layer(RNFL) thickness were obtained by Cirrus optical coherence tomography(OCT). The diagnostic capabilities of OCT parameters were assessed by area under receiver operating characteristic(AUROC) curves. RESULTS: Among all the OCT thickness parameters, no statistical significant difference between NTG group and POAG group was found(all P>0.05). In discriminating NTG or POAG from normal subjects, the average and inferior RNFL thickness, and the minimum GCIPL thickness had better diagnostic capabilities. There was no significant difference in AUROC curve between the best GCIPL thickness parameter(minimum GCIPL) and the best RNFL thickness parameter in discriminating NTG(inferior RNFL;P=0.076) and indiscriminating POAG(average RNFL;P=0.913) from normal eyes.CONCLUSION: Localized GCIPL loss, especially in the inferior and inferotemporal sectors, is more common in NTG than in POAG. Among all the GCIPL thickness parameters, the minimum GCIPL thickness has the best diagnostic performance in differentiating NTG or POAG from normal subjects, which is comparable to that of the average and inferior RNFL thickness.

Retinal ganglion cell-inner plexiform and nerve fiber layers in neuromyelitis optica

AIM： To determine the thickness of the retinal ganglion cell-inner plexiform layer（GCIPL） and the retinal nerve fiber layer（RNFL） in patients with neuromyelitis optica（NMO）.METHODS： We conducted a cross-sectional study that included 30 NMO patients with a total of 60 eyes. Based on the presence or absence of optic neuritis（ON）, subjects were divided into either the NMO-ON group（30 eyes） or the NMO-ON contra group（10 eyes）. A detailed ophthalmologic examination was performed for each group; subsequently, the GCIPL and the RNFL were measured using highdefinition optical coherence tomography（OCT）. RESULTS： In the NMO-ON group, the mean GCIPL thickness was 69.28±21.12 μm, the minimum GCIPL thickness was 66.02±10.02 μm, and the RNFL thickness were 109.33±11.23, 110.47±3.10, 64.92±12.71 and 71.21±50.22 μm in the superior, inferior, temporal and nasal quadrants, respectively. In the NMO-ON contra group, the mean GCIPL thickness was 85.12±17.09 μm, the minimum GCIPL thickness was 25.39±25.1 μm, and the RNFL thicknesses were 148.33±23.22, 126.36±23.45, 82.21±22.30 and 83.36±31.28 μm in the superior, inferior, temporal and nasal quadrants, respectively. In the control group, the mean GCIPL thickness was 86.98±22.37 μm, the minimum GCIPL thickness was 85.28±10.75 μm, and the RNFL thicknesses were 150.22±22.73, 154.79±60.23, 82.33±7.01 and 85.62±13.81 μm in the superior, inferior, temporal and nasal quadrants, respectively. The GCIPL and RNFL were thinner in the NMO-ON contra group than in the control group（P〈0.05）; additionally, the RNFL was thinner in the inferior quadrant in the NMO-ON group than in the control group（P〈0.05）. Significant correlations were observed between the GCIPL and RNFL thickness measurements as well as between thickness measurements and the two visual field parameters of mean deviation（MD） and corrected pattern standard deviation（PSD） in the NMO-ON group（P〈0.05）. CONCLUSION： The thickness of the GCIPL and RNFL, as measured using OCT, may indicate optic nerve damage in patients with NMO.

BOUNDARY AND INTERIOR LAYER BEHAVIOR FOR SINGULARLY PERTURBED VECTOR PROBLEM

In this paper, we consider the vector nonlinear boundary value problem:where is a small parameter,f and g are continuous functions in R4 Under appropriate assumptions, by means of the differential inequalities, we demonstrate the existence and estimation, involving boundary and interior layers, of the solutions to the above problem.

Characteristics of Corrosion Product Layer Formed on Weathering Steel Exposed to the Tropical Climate of Vietnam

The weathering steel (Corten B) was exposed to out-door atmosphere of Hanoi (urban site) and Donghoi (marine site). The results showed the protective ability of corrosion product layer formed on weathering steel in the initial stage. The SEM-EDX analysis detected the presence of chromium and copper in the inner layers of corrosion product formed on weathering steel. These elements improved corrosion resistance of corrosion product layers. In addition, the dense α-FeOOH phase were appeared early in corrosion product which is detected by X-ray diffraction and Micro Raman investigations. The results of polarization and EIS measurements also demonstrated the protectiveness of the corrosion product of weathering steel.

Research of precise pulse plasma arc powder welding technology of thin-walled inner hole parts

The inner hole parts played an oriented or supporting role in engineering machinery and equipment,which are prone to appear surface damages such as wear,strain and corrosion. The precise pulse plasma arc powder welding method is used for surface damage repairing of inner hole parts in this paper. The working principle and process of the technology are illustrated,and the microstructure and property of repairing layer by precise pulse plasma powder welding and CO2 gas shielded welding are tested and observed by microscope,micro hardness tester and X-ray residual stress tester etc. Results showed that the substrate deformation of thin-walled inner hole parts samples by precise pulse plasma powder welding is relatively small. The repair layer and substrate is metallurgical bonding,the transition zones( including fusion zone and heat affected zone) are relatively narrow and the welding quality is good. It showed that the thin-walled inner hole parts can be repaired by this technology and equipment.

光致变色纱线在多层织物设计中的应用

为了丰富织物的多样性,利用光致变色纱线,结合表里换层双层组织,设计与开发了“P”字图案表里换层光致变色面料;并进一步设计与开发了上、中层表里换层结构的“E”字图案三层组织光致变色面料,实现了织物在光线照射下单面变色,而反面不显变色的特殊效果。将光致变色纱线与表里换层结构的双层或多层织物相结合,可以形成新型光致变色功能面料,为此类产品的开发与设计提供了一种新思路。

婴儿纸尿裤内贴层非织造布的常规性能检测

婴儿纸尿裤的内贴层直接与婴儿皮肤接触,主要起到将尿液导向芯层的透水作用。织物的布面情况、克重、强力、断裂伸长率、亲水性、透水性都对终端产品性能有着重要的影响,本文通过研究生产需检测的指标、方法及检测标准,积极探索纸尿裤新国标的适用性。

载重轮胎轻量化异型过渡层的设计方法

介绍载重轮胎轻量化异型过渡层的设计方法。设计步骤包括划分理论功能区、确定内衬层设计的主要参考区域、确定主要参考区域过渡层成品标准理论厚度的最小值、计算主要参考区域过渡层半成品的拉伸率和设计厚度等。按照本方法设计过渡层的具体施工尺寸,能够有效降低半成品成本,同时解决传统设计存在的内衬层裂口、胎圈内裂口、轮胎内轮廓不佳、胎肩脱层和保压性能不佳等问题。通过内轮廓优化改善轮胎的承载性能,提高轮胎的耐久性能,延长使用寿命。

层状地基中海洋大直径管桩水平动力响应分析

考虑桩−海水−层状土相互作用,研究了水平动荷载作用下层状地基中海洋大直径管桩的动力响应特性。将海水视为无黏性可压缩流体介质建立桩周、桩芯海水的运动方程,通过分离变量法并结合海水的边界条件求得桩周、桩芯海水作用在管桩上的动水压力。将海床土体视为黏弹性介质并考虑其成层非均质性,利用微分变化并结合土体振动边界条件解得桩周、桩芯土体作用在管桩上的水平抗力。进而根据各桩段上水平力的平衡建立管桩控制方程,利用传递矩阵法并结合桩身的连续条件以及桩顶、桩底的边界条件,得到层状海床土中海洋大直径管桩的水平动力响应解析解,给出了桩顶位移解析表达式。将所得解与有限元模拟结果以及退化解与已有文献解进行对比,验证了本研究计算方法的合理性。并基于所得解分析了管桩−海水−层状土系统水平动力响应对动水压力、水深、土体模量、土层厚度等关键参数的敏感性。

0.01%阿托品滴眼液对不同程度近视儿童黄斑微循环的影响

目的:研究0.01%阿托品滴眼液对不同程度近视儿童黄斑血流密度及视网膜厚度的影响。方法:前瞻性自身对照研究。64例(112眼)首次诊断为屈光不正(近视)的患者在使用0.01%阿托品滴眼液治疗前及用药6个月后进行眼科检查,包括裸眼远视力(uncorrecte d distance visual acuity,UCVA)、眼轴(axial length,AL)、等效球镜度数(spherical equivalent,SE)、裂隙灯检查及使用光学相干断层扫描(optical coherence tomography,OCT)常规模式测量黄斑神经节细胞-内丛状层厚度(macular ganglion cell-inner plexiform layer thicknes,mGCIPL)。使用光学相干断层扫描血管成像(optical coherence tomography angiography,OCTA)测量黄斑区血管密度、中心凹无血管区面积等。比较用药前后各项指标的变化。结果:3组近视患者AL均较用药前显著增长(P<0.01),但低、中度近视用药前后差值明显小于高度近视组;3组近视患者SE均较用药前增长,但低度近视组用药前后差异无统计学意义(P>0.05),中度、高度近视组差异均具有统计学意义(P<0.01);3组近视患者眼压(intraocular pressure,IOP)较用药前无明显变化(P>0.05)。用药6个月后,中心圆黄斑血管密度(central circle macular vessel density,cCVD)增加在低度、中度近视组中均有统计学差异(P<0.01),在高度近视组中差异无统计学意义(P>0.05)。3个近视组用药前后外圆黄斑血管密度(outer circle macular vessel density,oCVD)、内圆黄斑血管密度(inner circle macular vessel density,iCVD)、全圆黄斑血管密度(whole circle macular vessel density,wCVD)无明显改变(P>0.05);mGCIPL增加在低度近视组中有统计学差异(P<0.01),在中度、高度近视组中均无统计学差异(P>0.05)。3个近视组黄斑中心凹无血管区(foveal avascular zone,FAZ)面积在用药前后无明显改变(P>0.05)。3个近视组中cCVD和AL、SE之间均无相关性(P>0.01),低度近视组中c CVD与m GCIPL呈低度相关(r=0.442,P<0.05),中度、高度近视组中cCVD与mGCIPL均无相关性(P>0.01)。结论:0.01%阿托品滴眼液可以明显降低低度近视患儿AL增长及屈光度增长速度,增加低、中度近视患儿黄斑中心圆血管密度,增加低度近视患儿m GCIPL厚度。

儿童青少年近视程度与黄斑中心凹脉络膜厚度及神经节细胞-内丛状层厚度的关系及影响因素

目的观察并分析儿童青少年近视等效球镜度(SE)与黄斑中心凹脉络膜厚度(SFCT)、视网膜神经节细胞-内丛状层(GCIPL)厚度、眼轴长度(AL)的相关性研究。方法回顾性病例研究。选取2021年1月至2022年7月就诊于北京市普仁医院眼科的8~14岁的儿童青少年,睫状肌麻痹验光测量屈光度,按照SE分为低度近视组(>-3 D且<-0.5 D)、中度近视组(>-6 D且≤-3 D)、高度近视组(≥-12 D且≤-6 D)和对照组(>-0.5 D且<0.5 D),并测量SFCT、GCIPL六个方位厚度(上方、鼻上、鼻下、下方、颞下、颞上)、GCIPL平均厚度、最小厚度和AL,评估其与近视屈光度数的关系。GCIPL厚度与AL采用Spearman相关系数分析,SFCT与AL采用广义估计方程分析。结果共纳入97例(142只眼),男性47例,女性50例,年龄(11.2±1.8)岁。GCIPL厚度与AL的Spearman相关系数及GCIPL厚度与AL的Spearman相关系数分析结果显示:GCIPL厚度各个指标与AL均呈现出显著负相关(P<0.001),GCIPL上方,下方,颞下方及平均厚度与年龄显著负相关,其余指标和年龄均无显著相关。广义估计方程结果显示:AL的回归系数值为-24.846(Z=-4.522,P<0.001),意味着AL对SFCT有显著的负向影响关系。结论儿童青少年近视SE越深,AL越长,SFCT越薄,GCIPL越薄,并且GCIPL下方与SE程度相关性最显著。

基于感知哈希的能源数据安全访问控制方法研究

作为保证能源数据安全的重要步骤,访问控制过程易受数据差异性、不均衡性、冗余性等问题的干扰,导致安全访问控制时间增加、交互成功率下降以及计算开销增加。为了有效解决这一问题,提出基于感知哈希的能源数据安全访问控制方法。采用监督判别投影算法对能源数据做降维处理,以降低信息之间的冗余性。利用感知哈希算法,得到分布式存储数据。结合二元一次函数诱导算法,在分布式存储数据中生成密钥。通过内层加密与外层加密相结合的控制策略,实现数据授权访问的动态变化,完成能源数据的安全访问控制。试验结果表明,该方法的能源数据安全访问控制时间短、交互成功率高、计算开销小。该方法可为能源数据安全领域的进一步发展提供重要参考。

广域SS-OCTA下早期糖尿病性视网膜病黄斑区的改变

目的基于广域扫频光学相干断层扫描血管成像(SS-OCTA)观察早期糖尿病性视网膜病变(DR)黄斑视网膜微循环的改变及神经节细胞内丛状层(GC-IPL)结构的变化及其相关性。方法于2023年07月至2023年08月在安徽理工大学第一附属医院眼科共招募105例105眼DR患者,分为无DR组(NDR)53眼和轻至中度非增殖性DR组(NPDR)52眼两组,53例健康受试者作为对照组。采用SS-OCTA以黄斑为中心的12mm×12mm扫描成像并自动定量测算黄斑不同分区的浅层血管复合体(SVC)、深层血管复合体(DVC)的血管密度(VD)、灌注面积(PA),SVC的小血管密度(SVD)以及神经节细胞内从状层(GC-IPL)厚度,并进行相关性分析。结果与对照组相比,NDR组DVC中只有鼻侧象限PA差异有统计学意义(P=0.035);NPDR组除了SVC中VD的上、颞侧象限、PA的上象限、DVC中VD的鼻侧象限差异没有统计学意义(P=0.443、P=0.302、P=0.644、P=0.129),其余均有统计学意义(P<0.05)。与NDR组相比,NPDR组的SVC、DVC中平均VD、总PA以及各象限的和SVC中SVD平均以及各象限的差异均有统计学意义(P<0.05)。与对照组、NDR组相比,NPDR组鼻侧象限GC-IPL的差异均有统计学意义(P=0.020、P=0.003);与对照组相比,NDR组GC-IPL中的差异以及各象限无统计学意义(P=1.000)。在Spearman相关分析中,鼻侧象限GC-IPL与SVC中平均VD、总PA、SVD呈正相关性(r=0.438,P<0.001;r=0.417,P<0.001;r=0.439,P<0.001),中等相关;与DVC中平均VD、总PA呈正相关性(r=0.247,P=0.002;r=0.360,P<0.001),弱相关。结论随着DR进展,广域SS-OCTA可观察到视网膜微循环先代偿性增加后下降。浅层小血管的密度可作为临床前糖尿病视网膜病变早期客观检测影像学标志。早期DR视网膜微循环的改变和视网膜神经改变存在相关性。

柔性复合管在油田服役后的性能

为评价柔性复合管在油气田地面集输系统中的应用效果,采用宏观观察、微观分析、水压爆破试验、气密封性能测试、结构组成分析、热分析、红外光谱分析、力学性能测试等方法对两条柔性复合管进行分析,以确定其在不同工况下的适用性。结果表明:在经过一段时间的服役后,两条柔性复合管结构层保持完整,未发现明显缺陷,内衬层颜色加深;两条管道的失效形式均为管体爆破,其中1号试样因长期高温运行,其爆破压力不满足标准要求;两条管道的内衬层分别为交联聚乙烯和普通聚乙烯,增强层分别为芳纶纤维和涤纶纤维,热分解温度分别为580℃和440℃,但芳纶纤维的抗拉强度明显小于涤纶纤维。

航空多层铆接结构内层裂纹的远场涡流检测

多层铆接结构是飞机机身蒙皮与型材的主要结构。由于周期性载荷作用,其内部型材等承力部位易产生疲劳裂纹,该位置隐蔽性强,采用目视或常规无损检测技术难以检测出这些缺陷。而远场涡流检测技术可检测埋藏深度大的缺陷,采用该技术对飞机多层铆接结构的内层裂纹进行检测。结果表明:选择合适的检测频率时,检测信号阻抗的幅值与裂纹深度、检测信号阻抗的相位角与裂纹埋藏深度均呈良好的线性关系,对于确定的被检材料和检测传感器,得出的拟合公式可为裂纹损伤的定位、定量检测提供理论参考依据,从而获得裂纹的准确信息,实现裂纹损伤的准确定位和定量检测。