Prophylactic Pattern Scanning Laser Retinal Photocoagulation for Diabetic Retinopathy in Spontaneously Diabetic Torii Fatty Rats: Preliminary Experimental Results

Research Background and Purpose: The number of diabetic patients is rapidly increasing, making it crucial to find methods to prevent diabetic retinopathy (DR), a leading cause of blindness. We investigated the effects of prophylactic pattern scanning laser retinal photocoagulation on DR development in Spontaneously Diabetic Torii (SDT) fatty rats as a new prevention approach. Methods: Photocoagulation was applied to the right eyes of 8-week-old Spontaneously Diabetic Torii (SDT) fatty rats, with the left eyes serving as untreated controls. Electroretinography at 9 and 39 weeks of age and pathological examinations, including immunohistochemistry for vascular endothelial growth factor and glial fibrillary acidic protein at 24 and 40 weeks of age, were performed on both eyes. Results: There were no significant differences in amplitude and prolongation of the OP waves between the right and left eyes in SDT fatty rats at 39 weeks of age. Similarly, no significant differences in pathology and immunohistochemistry were observed between the right and left eyes in SDT fatty rats at 24 and 40 weeks of age. Conclusion: Prophylactic pattern scanning retinal laser photocoagulation did not affect the development of diabetic retinopathy in SDT fatty rats.

Pattern Scan Laser Photocoagulator on Retinopathy: an annual clinical application summary

Purpose:To evaluate the clinical efficacy of Pattern Scan Laser Photocoagulator (PASCAL) by observing the efficacy of PASCAL on retinopathy.Methods:A total of 92 patients with retinopathy (121 eyes) who underwent PASCAL between December 2008 and February 2009 in our center were retrospectively analyzed to evaluate the visual acuity changes and recovery conditions of the patients from baseline to posterior to the treatment.The retinopathy included:diabetic retinopathy,ischemic retinal vein occlusion.(IRVO),central serous chorioretinopathy (CSC),retinal periphlebitis (Eales disease) and retinal degeneration /holes.Results:The patients were subject to a 12-month follow up after PASCAL.The visual acuity findings were stated as below:for diabetic retinopathy.(73 eyes),10 eyes had improved visual acuity;55 eyes were stabilized and 8 eyes progressed;for IRVO (13 eyes),4 eyes showed improvement,6 eyes were stabilized and 3 eyes progressed;for CSC (9 eyes),6 eyes were alleviated and 3 eyes progressed;for retinal periphlebitis (5 eyes),2 eyes had enhanced visual acuity and 3 eyes showed stable visual acuity;for retinal degeneration /holes (21 eyes),5 eyes presented improved visu-al acuity,16 eyes were stabilized and no eye progressed.Indirect ophthalmoscopic reexamination confirmed secured blockage by laser spots and favorable absorption of the retinal edema and newborn capillaries.No obvious leakage was observed during fundus fluorescein angiography and no laser-related ocular adverse effect was reported.Conclusion:PASCAL is accurate,effective and well-tolerated.The duration of short laser pulse falls within the safety range,ensuring the stabilization and improvement in the pa-tient's visual acuity.The parameters,long-term efficacy and complications of PASCAL should be further demonstrated by performing long-term clinical trials with larger sample size.

Long-term effects of pattern scan laser pan-retinal photocoagulation on diabetic retinopathy in Chinese patients: a retrospective study

●AIM:To evaluate the long-term effects of pattern scan laser(PASCAL)pan-retinal photocoagulation(PRP)on diabetic retinopathy(DR)in Chinese patients.●METHODS:In this retrospective study,we evaluated clinical data of 29 patients(53 eyes)with severe non-proliferative DR(SNPDR)or proliferative DR(PDR)who received PRP and follow-up at our hospital from 2008 to 2013.Sixteen patients(29 eyes)received PASCAL PRP and 13 patients(24 eyes)received 100-ms conventional laser PRP.●RESULTS:After long-term follow-up(mean,min-max days:719.8,290-1666 for PASCAL PRP vs 743.5,240-1348 for conventional PRP,P=0.569),patients receiving PASCAL PRP required fewer photocoagulation sessions than the conventional PRP group(2.6±1.0 vs 3.9±0.9,P<0.01).Best corrected visual acuity(BCVA)was reduced slightly in PASCAL PRP group while reduced significantly in conventional PRP group.At last visit,24 eyes in the PASCAL group(88.9%)and 21 eyes in the conventional group(91.7%)were improved or stable.Two eyes in PASCAL PRP group(7.4%)and 3 eyes in the conventional PRP group(12.5%)developed vitreous hemorrhage or vitreous fibrovascular proliferation.●CONCLUSION:PASCAL PRP is as effective and may be more conducive to maintaining visual acuity with less treatment sessions for DR treatment compared to conventional laser PRP.

Experimental Investigation of Laser Surface Hardening of AISI 4340 Steel Using Different Laser Scanning Patterns

Laser surface transformation hardening becomes one of the most modern processes used to improve fatigue and wear properties of steel surfaces. In this process, the material properties and the heating parameters are the factors that present the most significant effects on the hardened surface attributes. The control of these factors using predictive modeling approaches to achieve desired surface properties leads to conclusive results. However, when the dimensions of the surface to be treated are larger than the cross-section of the laser beam, various laser-scanning patterns are involved. This paper presents an experimental investigation of laser surface hardening of AISI 4340 steel using different laser scanning patterns. This investigation is based on a structured experimental design using the Taguchi method and improved statistical analysis tools. Experiments are carried out using a 3 kW Nd: YAG laser source in order to evaluate the effects of the heating parameters and patterns design parameters on the physical and geometrical characteristics of the hardened surface. Laser power, scanning speed and scanning patterns (linear, sinusoidal, triangular and trochoid) are the factors used to evaluate the hardened depth and the hardened width variations and to identify the possible relationship between these factors and the hardened zone attributes. Various statistical tools such as ANOVA, correlations analysis and response surfaces are applied in order to examine the effects of the experimental factors on the hardened surface characteristics. The results reveal that the scanning patterns do not modify the nature of the laser parameters’ effects on the hardened depth and the hardened width. But they can accentuate or reduce these effects depending on the type of the considered pattern. The results show also that the sinusoidal and the triangular patterns are relevant when a maximum hardened width with an acceptable hardened depth is desired.

Numerical Investigation of Laser Surface Hardening of AISI 4340 Using 3D FEM Model for Thermal Analysis of Different Laser Scanning Patterns

Laser surface hardening is becoming one of the most successful heat treatment processes for improving wear and fatigue properties of steel parts. In this process, the heating system parameters and the material properties have important effects on the achieved hardened surface characteristics. The control of these variables using predictive modeling strategies leads to the desired surface properties without following the fastidious trial and error method. However, when the dimensions of the surface to be treated are larger than the cross section of the laser beam, various laser scanning patterns can be used. Due to their effects on the hardened surface properties, the attributes of the selected scanning patterns become significant variables in the process. This paper presents numerical and experimental investigations of four scanning patterns for laser surface hardening of AISI 4340 steel. The investigations are based on exhaustive modelling and simulation efforts carried out using a 3D finite element thermal analysis and structured experimental study according to Taguchi method. The temperature distribution and the hardness profile attributes are used to evaluate the effects of heating parameters and patterns design parameters on the hardened surface characteristics. This is very useful for integrating the scanning patterns’ features in an efficient predictive modeling approach. A structured experimental design combined to improved statistical analysis tools is used to assess the 3D model performance. The experiments are performed on a 3 kW Nd:Yag laser system. The modeling results exhibit a great agreement between the predicted and measured values for the hardened surface characteristics. The model evaluation reveals also its ability to provide not only accurate and robust predictions of the temperature distribution and the hardness profile as well an in-depth analysis of the effects of the process parameters.

Achieving Directionality and Transmit Diversity via Integrating Beam Pattern Scanning (BPS) Antenna Arrays and OFDM

In this paper, we introduce a novel merger of antenna arrays with scanning beam patterns, and Orthogonal Frequency Division Multiplexing (OFDM) systems. Controlled time varying phase shifts are applied to the antenna array elements mounted at the base station with beam patterns directed toward the desired user. This creates a small beam pattern movement called Beam Pattern Scanning (BPS). In rich scattering environments BPS creates a time varying environment leading to time diversity exploitable at the receiver enhances its probability-of-error performance. Here, we apply OFDM signals to BPS antenna arrays, and we achieve: (1) directionality, which supports Space Division Multiple Access (SDMA);and (2) a time diversity gain, which leads to high performance. We discuss the structure of the base station antenna array and the OFDM receiver that exploits time diversity. We also introduce the merger of BPS and multi-carrier OFDM (MC-OFDM) systems. In MC-OFDM each bit is transmitted over all sub-carriers after serial to parallel conversion. BPS/ MC-OFDM receiver exploits both time diversity inherent in BPS, and frequency diversity inherent in MC-OFDM transmission technique. Simulation results show high Probability-of-error performance is achie- vable via BPS/OFDM and BPS/MC-OFDM schemes comparing to the traditional OFDM and MC-OFDM, respectively. Simulations also reveal that MC-OFDM system as well as its merger with BPS is capable of mitigating large Peak-to-Average Ratio (PAPR) problem in traditional OFDM system. In addition, performance simulations with coded OFDM (COFDM) and coded MC-OFDM (MC-COFDM) and their merger with BPS are studied.

微型光机电二维扫描镜的Lissajous与Linescan扫描对比

在激光扫描显示系统(LSDs)中,MOEMS对激光束的空间调制主要分为Lissajous与Linescan两种模式。为了深入分析各模式的扫描特点,比较各模式之间的优缺,针对每种模式提出了扫描显示分辨率和轨迹均匀性这两个指标进行对比研究。按照仿真分析得出的最小像元划分方法,相同分辨率下,Lissajous模式对MOEMS快轴频率的最低要求要比Linescan模式大约高57%。另外,利用Matlab对不同MOEMS模式进行同一图像的扫描仿真,仿真结果表明,Lissajous扫描轨迹呈现出上下边缘密、中心疏的不均匀特点,而Linescan扫描轨迹则呈现出喇叭状不均匀特点。

i-Scan染色与色素内镜技术诊断大肠肿瘤对比研究

目的探讨i-Scan染色内镜技术在大肠肿瘤病变诊断中的应用价值。方法应用高分辨率结肠镜检出大肠息肉样病变180个,应用i-Scan放大观察病变腺管开口类型(PP),预测病变的病理类型,并与染色内镜及病理组织学进行对照研究。结果高分辨率结肠镜i-Scan染色对大肠肿瘤的诊断敏感度为86.2%,特异度为78.9%,准确度为87.4%,阳性预测值为89.8%,阴性预测值为72.5%。色素内镜对大肠肿瘤的诊断敏感度为90.2%,特异度为85.9%,准确度为90.8%,阳性预测值为93.2%,阴性预测值为80.3%。两者对大肠肿瘤诊断敏感度、特异度及准确度比较均无显著性差异(P>0.05)。结论高分辨率结肠镜i-Scan染色能较准确预测大肠肿瘤的病理类型,准确度与色素内镜相当,具有较高的应用价值。

Fast Multi-Pattern Matching Algorithm on Compressed Network Traffic

Pattern matching is a fundamental approach to detect malicious behaviors and information over Internet, which has been gradually used in high-speed network traffic analysis. However, there is a performance bottleneck for multi-pattern matching on online compressed network traffic(CNT), this is because malicious and intrusion codes are often embedded into compressed network traffic. In this paper, we propose an online fast and multi-pattern matching algorithm on compressed network traffic(FMMCN). FMMCN employs two types of jumping, i.e. jumping during sliding window and a string jump scanning strategy to skip unnecessary compressed bytes. Moreover, FMMCN has the ability to efficiently process multiple large volume of networks such as HTTP traffic, vehicles traffic, and other Internet-based services. The experimental results show that FMMCN can ignore more than 89.5% of bytes, and its maximum speed reaches 176.470MB/s in a midrange switches device, which is faster than the current fastest algorithm ACCH by almost 73.15 MB/s.

常压储罐底板腐蚀的多源数据评价

为提高储罐检验效率和腐蚀评价准确性,通过某油田公司管辖储罐的损伤模式识别、在线声发射检测和开罐检验进行验证与评价,结果表明:罐体结构不合理易导致隔热层下腐蚀和土壤腐蚀,罐内部易发生微生物腐蚀和酸性(含硫)污水腐蚀;声发射检测可获取底板腐蚀状态和可能发生腐蚀的区域;空间数据扫描可间接获取因局部变形导致的腐蚀环境分布情况。因此,先通过声发射检测和空间数据扫描预判腐蚀损伤区域,可提高开罐检验效率和准确性。

激光后处理实现图案化结构色调控研究

为使人工制备的结构色实现色调的精确调控,本研究以硅片为衬底,采用自组装法制备聚苯乙烯微球(PS微球)的平面六角密堆积结构,通过磁控溅射方法在其上沉积不同厚度的金薄层;再利用532nm脉冲激光后处理,研究不同扫描速度的激光后处理对结构色薄膜呈色性能的影响。结果表明:镀膜时间相同,随激光扫描速度逐渐减小,样品扫描区域颜色的变化为玫红—橙红—橙黄—黄绿—蓝绿—蓝紫,反射光谱中心波长发生蓝移;在此基础上制备了图案化的样品,发现随着观察角度增加,扫描后区域的颜色发生蓝移。

基于激光雷达数据的塔里木河下游胡杨种群空间分布格局和种内竞争关系

【目的】分析胡杨种群在干旱区不同地下水埋深梯度下的空间分布格局及种内竞争强度变化,探究种群空间结构对干旱环境的响应特征。【方法】在塔里木河下游3个断面处离河道1 000 m的范围内等距离布设15个50 m×50 m天然胡杨林样地,利用地面激光雷达(TLS)获取树木三维结构数据,并通过聚集指数(R)、丛生指数(I)、点格局函数g(r)等空间分布指标以及竞争指数(CI),分析空间分布格局和种内竞争强度。【结果】1)R和I指数表明,在下游不同地下水埋深梯度下,胡杨种群空间分布格局整体上呈聚集分布。2)各样地内在0~25 m半径r距离获取的g(r)函数值分析表明,大部分样地胡杨在r<5 m距离内基本呈现聚集分布格局,在r>5 m距离呈随机分布格局。随着地下水埋深增加,树木聚集分布的距离r会缩小。3)点格局函数g_(12)(r)结果表明,不同龄级胡杨树分布格局存在差异,中龄树主要呈聚集分布,其他龄级树呈随机分布;中龄树与幼龄树、成熟树之间存在正关联性,表现出相互促进关系,而其他龄级树木之间未呈现显著关联性。4)平均CI指数随离河道距离增大呈递减趋势,单木CI随胸径增大逐渐递减。【结论】塔里木河下游胡杨种群在小尺度上呈聚集分布格局,随着尺度的增加主要呈现随机分布特征。随离河道距离增大和地下水位逐步降低,导致树木密度降低和种内平均竞争强度变弱,树木呈衰退趋势。

基于CLO-3D虚拟试衣的轮椅使用者裤装修正效果研究

结合CLO-3D虚拟试衣系统,针对女性轮椅使用者裤装板型合体性问题,利用省道与分割线设计方法进行坐姿状态板型修正。在静态直立板型的基础上建立轮椅使用者无障碍裤装坐姿板型基样,根据三维人体测量数据生成虚拟试衣模特,利用CLO-3D虚拟试衣软件中压力图、透视图、接触点和变形率这4个服装效果评价指标,对虚拟缝合后的立姿与坐姿裤装板型进行修正效果评价。最后,将样衣真实试穿效果与CLO-3D虚拟试衣效果进行对比,模拟效果与真实试穿效果基本一致。研究可为无障碍服装结构研究提供借鉴。

扫描雷达未知天线方向图误差下的稀疏目标角超分辨重建方法

扫描雷达角超分辨技术是基于目标与天线方向图的关系,采用解卷积方法获取超越实波束的角分辨能力。目前的角超分辨方法大都是基于理想的无畸变天线方向图,未考虑实际过程中方向图的变化。然而,由于雷达天线罩、天线测量误差与平台非理想运动等因素的影响,天线方向图在实际中往往存在未知的误差,会导致目标分辨能力下降,甚至产生虚假目标。针对此问题,该文提出一种机载扫描雷达未知天线方向图误差下的角超分辨成像方法。首先,基于总体最小二乘(TLS)准则,该文考虑了方向图误差矩阵的影响,导出了相应的目标函数;其次,基于交替迭代的求解思路,利用迭代重加权优化方法实现了目标函数求解;最后,针对算法超参数选取,引入了一种自适应参数选取方法。仿真与实测结果表明,该文方法能实现未知天线误差条件下的超分辨重建,进一步提升了超分辨算法的稳健性。

非竞技马拉松女性跑者与普通人群足型分类及差异对比

通过收集205位女性非竞技马拉松跑者和195位普通女性的足型数据,完成了两类女性人群的足型分类,并比较分析其足型差异。借助三维扫描仪获取包括长度、宽度、高度、围长、角度在内的23项足型数据,利用主成分分析降维,采用K-means聚类算法将普通女性人群足型分为短尖足、长宽足、短矮足,将非竞技马拉松女性跑者足型分为宽厚足、短窄足、窄平足,以探究非竞技马拉松女性跑者的足型规律;通过独立样本T检验分析,发现两类人群的足型在趾跖宽度、围长方面存在显著差异,非竞技马拉松女性跑者这两项指标的数值均大于普通女性人群。研究结论可以扩展非竞技马拉松女性跑者的足型数据库,并且为设计研制非竞技马拉松跑者的鞋楦提供一定的数据参考。

平面相控阵宽角扫描技术

宽角扫描技术是近年来平面相控阵研究领域的热点和难点。从2008年起,电子科技大学计算电磁学团队便开展了相关研究工作,提出了利用方向图可重构技术突破平面相控阵宽角扫描瓶颈的理论和实验方案,并逐步发展了基于电磁镜像原理、表面波辅助设计、磁流源技术、非周期阵列和时间反演自适应优化等理论和方法,用于实现平面相控阵宽角扫描。文章回顾了该团队在平面相控阵宽角扫描领域的研究历程,并对其研究发展做出展望。

文胸结构设计中主要细部尺寸的人体依据

为使文胸结构设计更加规范、科学,以三维人体测量为基础,通过对102位西部青年女性的乳房细部特征尺寸的测量,结合内衣企业文胸结构设计的特点,寻找文胸结构设计中主要细部尺寸的人体依据,分析人体乳房细部特征尺寸与文胸结构设计中主要控制部位尺寸间的关系;通过SPSS统计分析,建立了文胸结构设计中主要细部尺寸关于胸围、胸下围及胸差间的回归方程。

中场测量相控阵扫描方向图的方法研究

有源相控阵天线的发射和接收天线的性能依赖于阵面口径的幅相分布,有源相控阵的幅相校准工作通常在出厂前通过暗室中的平面近场测量进行,但是某些大型的有源阵面根本无法进暗室进行校准,利用外场测量进行的校准往往无法验证其结果的好坏,该文介绍了一种中场测量相控阵天线扫描方向图的方法,使校准结果能够得到较为客观的评估。

大型电扫相控阵雷达的天线方向图测试

天线方向图是天线辐射特性的重要参数,大型电扫相控阵雷达的天线方向图往往难以准确测量。扫描方向图是利用电扫相控阵波束捷变的特点形成的方向图,较为准确地表征了天线的辐射特性,是对天线方向图很好地近似。文中结合多个大型雷达的工程研制经验论述了在远场和中场测试天线方向图的方法,提高了测试效率和精度,得到了令人满意的结果。

使用“玫瑰线/螺线”图形扫描的双色红外制导技术

被动地响应双波段红外辐射,并且使用有效的图形扫描系统的目标跟踪寻的器,对于高背景的抑制、多目标及真假目标识别和动态范围的改进,都是十分有效的。本文对可以应用于反坦克导弹的导引头,使用“玫瑰线/螺线”图形扫描和双色红外探测的目标识别与跟踪系统作综合论述;对系统的工作原理、技术参数的确定以及最优化设计的问题,作较详细的分析与评述。