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Acute postoperatory visual loss following bilateral lung transplantation surgery:a case series
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作者 Rosa Gutierrez-Bonet Jorge Ruiz-Medrano +2 位作者 Maria Alarcon-Tomas Mónica Hijos Pilar Cifuentes-Canorea 《International Journal of Ophthalmology(English edition)》 SCIE CAS 2017年第5期822-825,共4页
Dear Editor,I am Rosa Gutiérrez Bonet,former ophthalmology resident at Puerta de Hierro University Hospital,Madrid,Spain.I write to present four cases of cortical blindness(CB)after bilateral lung transplant(L... Dear Editor,I am Rosa Gutiérrez Bonet,former ophthalmology resident at Puerta de Hierro University Hospital,Madrid,Spain.I write to present four cases of cortical blindness(CB)after bilateral lung transplant(LT). 展开更多
关键词 LUNG Acute postoperatory visual loss following bilateral lung transplantation surgery a case series CASE
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Ecstasy-induced optic disc swelling and consequent visual loss
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作者 Michaela Ramsauer Stephan Thurau +1 位作者 Siegfried Priglinger Efstathios Vounotrypidis 《International Journal of Ophthalmology(English edition)》 SCIE CAS 2020年第3期520-522,共3页
Dear Editor,We present the first reported case of unilateral optic disc swelling with subsequent persistent loss of vision triggered by ecstasy consumption in the case of a young man.Ecstasy is one of the most commonl... Dear Editor,We present the first reported case of unilateral optic disc swelling with subsequent persistent loss of vision triggered by ecstasy consumption in the case of a young man.Ecstasy is one of the most commonly consumed recreational drugs among young adults.Its main constituent and active substance is 3,4-methylenedioxymethamphetamine(MDMA). 展开更多
关键词 ECSTASY optic disc swelling visual loss
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Macular Perfusion Changes and Ganglion Cell Complex Loss in Patients with Silicone Oil-related Visual Loss 被引量:9
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作者 MA Ya ZHU Xiao Qing PENG Xiao Yan 《Biomedical and Environmental Sciences》 SCIE CAS CSCD 2020年第3期151-157,共7页
Objective The aim of this study was to investigate macular perfusion changes and ganglion cell complex(GCC)loss in patients with unexplained visual loss following vitrectomy and silicone oil(SO)tamponade,and to evalua... Objective The aim of this study was to investigate macular perfusion changes and ganglion cell complex(GCC)loss in patients with unexplained visual loss following vitrectomy and silicone oil(SO)tamponade,and to evaluate the correlation between retinal blood flow and GCC loss using optical coherence tomography angiography(OCTA)and optical coherence tomography(OCT).Methods This retrospective study included seven eyes(seven patients)with unexpected visual loss after vitrectomy and SO tamponade.OCTA was used to evaluate the alterations in retinal vessel density(VD)in the superficial capillary plexus(SCP),deep capillary plexus(DCP),and radial peripapillary capillary plexus(RPCP).OCT was used to measure the thickness of GCC and retinal nerve fiber layer(RNFL).Medical records of patients were reviewed.Results Quantitative analysis of OCTA images revealed a significant reduction in SCP VD in the affected eyes compared with the controls(all sections P<0.05).No difference was found in GCC thickness,but FLV(focal loss volume)and GLV(global loss volume)were significantly higher in the affected eyes(both P<0.001).SCP VD was inversely correlated with FLV and GLV.Conclusions Silicone oil-related severe visual loss was associated with superficial retinal microvasculature damage and ganglion cell apoptosis. 展开更多
关键词 SILICONE oil visual loss Optical coherence tomography ANGIOGRAPHY GANGLION cell complex
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Perioperative visual loss after spine surgery 被引量:8
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作者 Travis J Nickels Mariel R Manlapaz Ehab Farag 《World Journal of Orthopedics》 2014年第2期100-106,共7页
Perioperative visual loss(POVL) is an uncommon, but devastating complication that remains primarily associated with spine and cardiac surgery. The incidence and mechanisms of visual loss after surgery remain difficult... Perioperative visual loss(POVL) is an uncommon, but devastating complication that remains primarily associated with spine and cardiac surgery. The incidence and mechanisms of visual loss after surgery remain difficult to determine. According to the American Society of Anesthesiologists Postoperative Visual Loss Registry, the most common causes of POVL in spine procedures are the two different forms of ischemic optic neuropathy: anterior ischemic optic neuropathy and posterior ischemic optic neuropathy, accounting for 89% of the cases. Retinal ischemia, cortical blindness, and posterior reversible encephalopathy are also observed, but in a small minority of cases. A recent multicenter case control study has identified risk factors associated with ischemic optic neuropathy for patients undergoing prone spinal fusion surgery. These include obesity, male sex, Wilson frame use, longer anesthetic duration, greater estimated blood loss, and decreased percent colloid administration. These risk factors are thought to contribute to the elevation of venous pressure and interstitial edema, resulting in damage to the optic nerve by compression of the vessels that feed the optic nerve, venous infarction or direct mechanical compression. This review will expand on these findings as well as the recently updated American Society of Anesthesiologists practice advisory on POVL. There are no effectivetreatment options for POVL and the diagnosis is often irreversible, so efforts must focus on prevention and risk factor modification. The role of crystalloids versus colloids and the use of α-2 agonists to decrease intraocular pressure during prone spine surgery will also be discussed as a potential preventative strategy. 展开更多
关键词 PERIOPERATIVE visual loss Ischemic optic NEUROPATHY Central retinal artery occlusion Cortical BLINDNESS POSTERIOR reversible ENCEPHALOPATHY Spine surgery PRONE positioning
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Branch retinal vein thrombosis and visual loss probably associated with pegylated interferon therapy of chronic hepatitis C
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作者 Luciana Lofego Gonalves Alberto Queiroz Farias +2 位作者 Patrícia Lofego Gonalves Elbio Antonio D'Amico Flair José Carrilho 《World Journal of Gastroenterology》 SCIE CAS CSCD 2006年第28期4602-4603,共2页
有干扰素治疗的眼科的复杂并发症通常温和、可逆,不要求治疗的退却。我们报导把视觉损失可能与干扰素治疗联系了的一个病人的一个案例。长期的丙肝病毒感染(遗传型 1a ) 在一个 33 年的老无征状的人被诊断。他的过去的病历是不显蓍的... 有干扰素治疗的眼科的复杂并发症通常温和、可逆,不要求治疗的退却。我们报导把视觉损失可能与干扰素治疗联系了的一个病人的一个案例。长期的丙肝病毒感染(遗传型 1a ) 在一个 33 年的老无征状的人被诊断。他的过去的病历是不显蓍的,以前的平淡的眼科学检查是正常的。Pegylated 干扰素高山哈并且 ribavirin 被开始。三个星期以后,他报导了视觉的无痛苦的减小。眼科学检查显示出广泛的视网膜内出血和棉花羊毛点,与劣等的分支 retinal 静脉血栓联系了。抗病毒的治疗立即被中止,但是一年以后,他坚持严重地减少的视敏度。这个案例在 pegylated 干扰素治疗期间说明无法预言、严重的复杂并发症的可能性。 展开更多
关键词 视网膜静脉 血管血栓形成 干扰素 治疗 丙型病毒肝炎
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Visual Loss after Cardiopulmonary Bypass (CABG) for Coronary Artery Disease: A Report of Case
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作者 Christos Simoglou Fotios Konstantinou +2 位作者 Dimitrios Mikroulis Savvas Elefteriadis Georgios Bougioukas 《World Journal of Cardiovascular Surgery》 2015年第5期45-48,共4页
We are reporting a 59-year-old male who presented with features of bilateral anterior ischaemic optic neuropathy after coronary artery bypass grafting. Postoperative vision loss after major nonocular surgery is a very... We are reporting a 59-year-old male who presented with features of bilateral anterior ischaemic optic neuropathy after coronary artery bypass grafting. Postoperative vision loss after major nonocular surgery is a very rare but devastating complication since it has the potential to cause bilateral, severe and permanent loss of vision. 展开更多
关键词 CARDIOPULMONARY BYPASS visual loss Ophthalmological Test Cross-Clamp EXTRACORPOREAL Circulation
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Bruch's membrane opening-minimum rim width and visual field loss in glaucoma:a broken stick analysis 被引量:1
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作者 Keun-Heung Park Ji-Woong Lee +2 位作者 Jin-Mi Kim Kouros Nouri-Mahdavi Joseph Caprioli 《International Journal of Ophthalmology(English edition)》 SCIE CAS 2018年第5期828-834,共7页
AIM:To determine the Bruch's membrane opening-minimum rim width(BMO-MRW) tipping point where corresponding visual field(VF) damages become detectable.METHODS:A total of 85 normal subjects and 83 glaucoma patie... AIM:To determine the Bruch's membrane opening-minimum rim width(BMO-MRW) tipping point where corresponding visual field(VF) damages become detectable.METHODS:A total of 85 normal subjects and 83 glaucoma patients(one eye per participant) were recruited for the study.All of the patients had VF examinations and spectral-domain optical coherence tomography to measure the BMO-MRW.Total deviation values for 52 VF points were allocated to the corresponding sector according to the Garway-Heath distribution map.To evaluate the relationship between VF loss and BMOMRW measurements,a "broken-stick" statistical model was used.The tipping point where the VF values started to sharply decrease as a function of BMO-MRW measurements was estimated and the slopes above and below this tipping point were compared.RESULTS:A 25.9% global BMO-MRW loss from normative value was required for the VF loss to be detectable.Sectorally,substantial BMO-MRW thinning in inferotemporal sector(33.1%) and relatively less BMO-MRW thinning in the superotemporal sector(8.9%) were necessary for the detection of the VF loss.Beyond the tipping point,the slopes were close to zero throughout all of the sectors and the VF loss was unrelated to the BMO-MRW loss.The VF loss was related to the BMO-MRW loss below the tipping point.The difference between the two slopes was statistically significant(P≤0.002).CONCLUSION:Substantial BMO-MRW loss appears to be necessary for VF loss to be detectable in patients with open angle glaucoma with standard achromatic perimetry. 展开更多
关键词 Bruch's membrane opening-minimum rim width visual field loss structure function relationship broken stick model optical coherence tomography
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Impact of binocular visual field loss on driving performance in glaucoma patients
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作者 Zhen-Ying Jiang Jing Chen +1 位作者 Jing Yao Shao-Hong Qian 《International Journal of Ophthalmology(English edition)》 SCIE CAS 2021年第1期112-119,共8页
AIM:To evaluate the driving performance in young and middle-aged Chinese glaucoma patients with mild to severe visual field loss compared to those without glaucoma by using a driving simulation test.METHODS:Twenty-nin... AIM:To evaluate the driving performance in young and middle-aged Chinese glaucoma patients with mild to severe visual field loss compared to those without glaucoma by using a driving simulation test.METHODS:Twenty-nine participants were included in this study:nine patients with glaucoma but pass the binocular Esterman visual field test,ten patients with glaucoma and fail the binocular Esterman visual field test,and ten age-matched healthy controls.A driving simulation test was designed as a frequency-based analysis of a lanekeeping task.The total performance error,the controlresponse amplitude and delay were calculated.RESULTS:Esterman visual field test fail group showed the longest delay of control-response among three groups(P=0.02).And the delay in lane-keeping task was significantly associated with inferior field of better-eye(r=0.51,P=0.004)and integrated visual field(r=0.55,P=0.002).CONCLUSION:Young and middle-aged glaucoma patients with binocular visual field loss suffered from a longer delay of response in driving simulation test,while inferior visual field having more impact than superior visual field. 展开更多
关键词 driving simulation binocular visual field loss GLAUCOMA young middle-aged
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Calculation and Management for Mining Loss and Dilution under 3D Visualization Technical Condition 被引量:3
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作者 Weijing Wang Shaofeng Huang +1 位作者 Xiaobo Wu Qingfei Ma 《Journal of Software Engineering and Applications》 2011年第5期329-334,共6页
The mining loss rate and dilution rate are the key indicators for the mining technology and management level of mining enterprises. Aiming at the practical problems such as the large workload but inaccurate data of th... The mining loss rate and dilution rate are the key indicators for the mining technology and management level of mining enterprises. Aiming at the practical problems such as the large workload but inaccurate data of the traditional loss and dilution calculation method, this thesis introduces the operating principle and process of calculating the loss rate and dilution rate at the mining fields by adopting geological models. As an example, authors establishes 3D models of orebody units in the exhausted area and mining fields in Yangshu Gold Mine in Liaoning Province, and conduct Boolean calculation among the models to obtain the calculation parameters of loss and dilution, and thereby calculate out the dilution rate and loss rate of the mining fields more quickly and accurately. 展开更多
关键词 CALCULATION and MANAGEMENT MINING loss and DILUTION 3D visualIZATION Introduction
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超声波干涉及可视化实验装置研制
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作者 王亚平 韩睿 +2 位作者 周志赋 宋哲 滕永平 《实验室研究与探索》 CAS 北大核心 2024年第5期52-55,共4页
为了丰富大学物理声学实验内容,研制了一种多功能超声波干涉实验装置。基于空气介质设计了双振子干涉声速测量实验和半波损失验证实验。分别采用干涉声场测量法和干涉条纹移动法进行声速测量实验,并利用示波器实现了干涉声场声压分布的... 为了丰富大学物理声学实验内容,研制了一种多功能超声波干涉实验装置。基于空气介质设计了双振子干涉声速测量实验和半波损失验证实验。分别采用干涉声场测量法和干涉条纹移动法进行声速测量实验,并利用示波器实现了干涉声场声压分布的可视化。分别以有机玻璃、橡胶和玻璃为反射面材料,利用干涉法验证掠入射条件下的半波损失现象,并估算出掠入射角的范围。该实验装置实验现象明显、可操作性强,获评北京市第十六届大学生物理实验竞赛一等奖。 展开更多
关键词 超声波干涉 声速测量 可视化 半波损失 掠入射角
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预应力混凝土风机塔架结构安全性影响因素研究
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作者 张俊俊 甄理 +3 位作者 黄昊 孙林远 刘志鹏 陈改新 《水电能源科学》 北大核心 2024年第5期202-206,130,共6页
预应力混凝土塔架较钢制塔架具有更高的抗疲劳特性及稳定性,能够满足复杂地形的建设需求。基于现场监测数据,利用混凝土塑性损伤模型对塔架结构进行全尺寸建模,通过对比监测数据与数值仿真结果,研究了预应力损失、混凝土劣化及表观缺陷... 预应力混凝土塔架较钢制塔架具有更高的抗疲劳特性及稳定性,能够满足复杂地形的建设需求。基于现场监测数据,利用混凝土塑性损伤模型对塔架结构进行全尺寸建模,通过对比监测数据与数值仿真结果,研究了预应力损失、混凝土劣化及表观缺陷等因素对塔架结构力学性能的影响规律。结果表明,预应力混凝土塔架结构安全受多种因素影响,随着结构的劣化塔架刚度逐渐软化,低阶振型对结构共振的影响较大,塔架结构损伤形式趋向于受拉破坏。 展开更多
关键词 混凝土塔架 预应力损失 混凝土劣化 表观缺陷 塑性损伤
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糖尿病对初次全膝关节置换围术期失血量和疼痛的影响
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作者 齐浩东 鲁超 +2 位作者 徐韩博 王孟飞 郝阳泉 《中国组织工程研究》 CAS 北大核心 2024年第9期1383-1387,共5页
背景:全膝关节置换是终末期骨关节炎的主要治疗措施,但糖尿病会影响治疗效果和预后等。目的:探讨糖尿病对初次全膝关节置换围术期失血量和置换后疼痛的影响。方法:回顾性分析2021年1-4月在西安交通大学附属红会医院骨坏死与关节重建病... 背景:全膝关节置换是终末期骨关节炎的主要治疗措施,但糖尿病会影响治疗效果和预后等。目的:探讨糖尿病对初次全膝关节置换围术期失血量和置换后疼痛的影响。方法:回顾性分析2021年1-4月在西安交通大学附属红会医院骨坏死与关节重建病区行初次全膝关节置换且符合纳入标准的154例患者的临床资料,根据糖尿病诊断标准分为非糖尿病组与糖尿病组,其中糖尿病组32例,男性9例,女性23例,年龄55-80(66.58±7.16)岁;非糖尿病组122例,男性34例,女性88例,年龄44-83(66.69±6.63)岁。记录两组患者围术期失血量(全失血量、隐性失血量、血红蛋白下降值和红细胞压积下降值),记录置换前和置换后的目测类比评分、HSS评分、Caprini评分等。结果与结论:①非糖尿病组的全失血量(729.93±233.83)mL显著低于糖尿病组(853.69±184.91)mL,差异有显著性意义(P<0.05),非糖尿病组的隐性失血量(624.40±233.19)mL显著低于糖尿病组(749.08±179.49)mL,差异有显著性意义(P<0.05);②置换前和置换后1个月非糖尿病组目测类比评分显著低于糖尿病组,差异有显著性意义(P<0.05),置换后3 d和置换后3个月非糖尿病组与糖尿病组的目测类比评分差异无显著性意义(P>0.05);③置换后1个月非糖尿病组HSS评分明显高于糖尿病组,差异有显著性意义(P<0.05),而置换后3个月两组HSS评分差异无显著性意义(P>0.05);④置换前和置换后3 d两组间Caprini评分差异无显著性意义(P>0.05);⑤结果表明,患糖尿病会增加初次全膝关节置换的全失血量和隐性失血量,在全膝关节置换后短期内,糖尿病会增加患者疼痛并影响关节功能恢复,但随时间延长其影响会逐渐消失。 展开更多
关键词 全膝关节置换术 糖尿病 骨关节炎 全失血量 隐性失血量 视觉模拟评分 康复
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预劈核与水平劈核方式在白内障超声乳化手术中的应用效果及对患者角膜内皮细胞损失和术后最佳矫正视力的影响
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作者 马小飞 《当代医学》 2024年第2期90-93,共4页
目的探讨预劈核与水平劈核方式在白内障超声乳化手术中的应用效果及对患者角膜内皮细胞损失及术后最佳矫正视力(BCVA)的影响。方法选取2020年10月至2021年10月于湘雅常德医院接受白内障超声乳化手术治疗的100例白内障患者作为研究对象,... 目的探讨预劈核与水平劈核方式在白内障超声乳化手术中的应用效果及对患者角膜内皮细胞损失及术后最佳矫正视力(BCVA)的影响。方法选取2020年10月至2021年10月于湘雅常德医院接受白内障超声乳化手术治疗的100例白内障患者作为研究对象,随机分为对照组与观察组,每组50例。对照组术中实施水平劈核治疗,观察组术中实施预劈核治疗。比较两组角膜内皮细胞参数、BCVA、角膜水肿分级、超声能量参数及术后并发症发生情况。结果术后,两组细胞数量均少于术前,但观察组角膜内皮细胞数量多于对照组,观察组细胞丢失率低于对照组,差异有统计学意义(P<0.05)。术前、术后1周,两组BCVA比较差异无统计学意义;术后1 d,观察组BCVA高于对照组,差异有统计学意义(P<0.05)。术后,观察组角膜轻度水肿、中重度水肿发生率均低于对照组,差异有统计学意义(P<0.05)。术后,观察组超声乳化时间短于对照组,平均超声能量、累积释放能量参数(CDE)均低于对照组,差异有统计学意义(P<0.05)。两组术中、术后均无严重并发症发生。结论与常规水平劈核相比,在白内障患者的超声乳化手术中应用预劈核方法可简化手术步骤、缩短乳化时间,减少角膜内皮细胞损失,降低CDE,对促进患者术后均具有积极意义。 展开更多
关键词 白内障 白内障超声乳化手术 预劈核 水平劈核 角膜内皮细胞损失 最佳矫正视力
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基于改进目标检测的动态场景SLAM研究
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作者 史蓝兮 颜文旭 +1 位作者 倪宏宇 赵峰 《系统仿真学报》 CAS CSCD 北大核心 2024年第4期1028-1042,共15页
针对单目SLAM在动态场景下存在的对极约束误匹配问题,提出一种基于目标检测的动态特征点选择方法,通过在特征提取时剔除SLAM系统前端图像帧中动态特征点,提高SLAM的定位精度。提出了一个改进的目标检测网络,利用重叠面积、距离相似度和... 针对单目SLAM在动态场景下存在的对极约束误匹配问题,提出一种基于目标检测的动态特征点选择方法,通过在特征提取时剔除SLAM系统前端图像帧中动态特征点,提高SLAM的定位精度。提出了一个改进的目标检测网络,利用重叠面积、距离相似度和余弦相似度构建描述边界框的回归损失函数,实现目标的准确定位,获得当前图像帧中物体特征点范围。判断物体类别,对于标记为动态的物体根据目标检测结果剔除前端图像帧中的动态特征点。根据静态特征点,采用对极约束进行两帧图像间的特征匹配估计位姿,对单目相机运动进行跟踪、建图与闭环检测。通过对目标检测网络的主干进行结构重参数化改进,提升推理过程的速度,保证整体系统运行的实时性。在公开数据集KITTI的11个序列上的实验结果表明:改进后的系统比ORB-SLAM3系统定位精度提升了23.4%,帧率可以达到30帧/s以上,在保证实时运行的条件下能有效提高动态场景下单目SLAM系统定位精度。 展开更多
关键词 视觉SLAM 对极约束 特征匹配 目标检测 IoU损失函数 结构重参数化
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Delayed Visual Recovery from Optic Nerve Injury Following a Procedure of Orbital Wall Reconstruction
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作者 Chengzhe Wu Yingjun Li +1 位作者 Xun Cui Zhengri Li 《Journal of Biosciences and Medicines》 2020年第1期38-41,共4页
The acute onset of the vision loss by optic never injury following orbital wall reconstruction, has been reported in 0.5% - 5.0% of the cases. Visual impairment can be recovered within an early period after injury. De... The acute onset of the vision loss by optic never injury following orbital wall reconstruction, has been reported in 0.5% - 5.0% of the cases. Visual impairment can be recovered within an early period after injury. Delayed visual recovery from optic nerve injury during a procedure of orbital wall reconstruction has not been reported. We report a case of delayed recovery from optic nerve injury which occurred following orbital wall reconstruction. A 78-year-old man underwent orbital wall reconstruction for medial wall fracture and resulting enophthalmos in the right eye, one week after a traffic accident. Immediate after surgery, postoperative visual acuity in the right eye decreased to light perception, and relative afferent pupillary defect (RAPD) was detected. In spite of mega-dose steroid treatment, the visual acuity did not improve. However, 8 months after surgery, visual acuity began to recover to 0.1, and the degree of RAPD decreased. Twelve months after surgery, visual acuity in the right eye was 0.4, and pupillary light reflex was normal. Our report suggests that patients with optic neuropathy by surgery or trauma require long-term follow-up, regardless of early response to mega-dose steroid treatment. 展开更多
关键词 visual loss DELAYED visual Recovery OPTIC Nerve Injury Mega-Dose STEROID
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Application of Weighted Cross-Entropy Loss Function in Intrusion Detection 被引量:2
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作者 Ziyun Zhou Hong Huang Binhao Fang 《Journal of Computer and Communications》 2021年第11期1-21,共21页
The deep learning model is overfitted and the accuracy of the test set is reduced when the deep learning model is trained in the network intrusion detection parameters, due to the traditional loss function convergence... The deep learning model is overfitted and the accuracy of the test set is reduced when the deep learning model is trained in the network intrusion detection parameters, due to the traditional loss function convergence problem. Firstly, we utilize a network model architecture combining Gelu activation function and deep neural network;Secondly, the cross-entropy loss function is improved to a weighted cross entropy loss function, and at last it is applied to intrusion detection to improve the accuracy of intrusion detection. In order to compare the effect of the experiment, the KDDcup99 data set, which is commonly used in intrusion detection, is selected as the experimental data and use accuracy, precision, recall and F1-score as evaluation parameters. The experimental results show that the model using the weighted cross-entropy loss function combined with the Gelu activation function under the deep neural network architecture improves the evaluation parameters by about 2% compared with the ordinary cross-entropy loss function model. Experiments prove that the weighted cross-entropy loss function can enhance the model’s ability to discriminate samples. 展开更多
关键词 Cross-Entropy loss Function visualization Analysis Intrusion Detection KDD Data Set ACCURACY
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Visual Basic 4.0版本中的通讯问题研究
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作者 李冰 张焱 《天津理工学院学报》 1998年第3期43-45,共3页
VisualBasic是深受程序员欢迎的一种编程软件.作者在利用VB的通讯控件进行通信口管理时,发现有数据丢失现象.本文分析了造成数据丢失的原因,提出了解决问题的方法,并在变电站计算机综合自动化控制系统中得到了应用.
关键词 visualBASIC 数据通讯 数据丢失 通讯控件
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灯泡贯流泵局部熵产与能量损失特性研究 被引量:4
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作者 潘强 孙龙月 +2 位作者 丁威 张德胜 施卫东 《西安交通大学学报》 EI CAS CSCD 北大核心 2023年第1期131-140,共10页
为了研究大型灯泡贯流泵的能量损失特性,采用基于有限体积法的数值模拟,结合局部熵产率和网格尺度,通过熵产理论定位贯流泵内能量损失较高的局部区域,分析了不同工况下各部件内局部熵产、能量损失和不稳定流动之间的关联。结果表明:贯... 为了研究大型灯泡贯流泵的能量损失特性,采用基于有限体积法的数值模拟,结合局部熵产率和网格尺度,通过熵产理论定位贯流泵内能量损失较高的局部区域,分析了不同工况下各部件内局部熵产、能量损失和不稳定流动之间的关联。结果表明:贯流泵系统熵产与试验功率损失保持较高的一致性,相比于大流量工况,小流量液流正冲角更容易诱导能量损失;叶轮轮缘局部熵产最高,体积占比14%的轮缘子域耗散熵产占比超过40%,由叶顶区泄漏流和泄漏涡导致;导叶轮毂和轮缘侧耗散熵产较高,且呈现轮毂侧分散、区域大极值小,轮缘侧集中、区域小极值大的分布特性;灯泡体能量损失在小流量工况下集中在尾部渐缩段,在大流量工况下集中在灯泡尾部的尾迹区。该研究成果对大型泵站群水力性能优化设计及高效、稳定运行具有参考价值。 展开更多
关键词 贯流泵 数值模拟 局部熵产 网格尺度 能量损失 可视化
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Overview of Quality of Life Research in Older People with Visual Impairment
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作者 Chong-Wen Wang Cecilia L. W. Chan Iris Chi 《Advances in Aging Research》 2014年第2期79-94,共16页
During the past two decades, a number of studies have investigated the health-related quality of life (HRQOL) of older people with visual impairment, but the information is fragmented concerning health care providers ... During the past two decades, a number of studies have investigated the health-related quality of life (HRQOL) of older people with visual impairment, but the information is fragmented concerning health care providers in the field of gerontology. In this review, findings of HRQOL studies in older adults with different types of age-related ocular disorders or conditions are summarized. Apart from medical treatment and vision rehabilitation, factors that may influence the HRQOL of visually impaired older adults are also examined, including age, gender, socioeconomic status, mobility, comorbidity, family support, social support, use of eye care services, and psychological and spiritual factors. Finally, existing problems are discussed and recommendations for future research are provided. Given the high prevalence of visual impairment among older adults and their unmet needs for eye care and vision rehabilitation, multidisciplinary interventions that may enhance visually impaired older people’s HRQOL are warranted. 展开更多
关键词 OLDER ADULTS Quality of Life Review VISION loss visual IMPAIRMENT
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采用DETR与先验知识融合的输电线路螺栓缺陷检测方法 被引量:2
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作者 李刚 张运涛 +1 位作者 汪文凯 张东阳 《图学学报》 CSCD 北大核心 2023年第3期438-447,共10页
为了解决深度学习模型无法学习螺栓目标的先验知识、仅通过视觉特征难以快速准确定位其缺陷以及螺栓缺陷样本数量有限、类别不平衡的问题,提出了将深度学习模型与螺栓先验知识相结合的方法。选取端到端目标检测(DETR)为基线模型,设计并... 为了解决深度学习模型无法学习螺栓目标的先验知识、仅通过视觉特征难以快速准确定位其缺陷以及螺栓缺陷样本数量有限、类别不平衡的问题,提出了将深度学习模型与螺栓先验知识相结合的方法。选取端到端目标检测(DETR)为基线模型,设计并实现了一种采用DETR与先验知识融合的改进DETR模型。首先,利用视觉-知识注意力模块将螺栓图像的视觉特征与螺栓先验知识有机融合,获得螺栓对应的增强视觉特征;然后,将增强视觉特征送入基于Transformer编码-解码结构的DETR模型框架中对螺栓目标进行识别与分类;最后,针对螺栓危急缺陷样本少及样本不平衡的问题,引入类增量学习损失函数(CILLF)来增强模型的鉴别能力,缓解螺栓缺陷样本间长尾分布问题。仿真实验结果表明:改进DETR模型在输电线路螺栓缺陷样本上的mAP相较于基线模型DETR提升了2.8个百分点;相较于主流Faster R-CNN,YOLOv5l模型,改进DETR模型在长尾分布下螺栓缺陷样本少的类别图像上的检测效果提升尤为显著。 展开更多
关键词 螺栓缺陷检测 TRANSFORMER DETR 先验知识 增强视觉特征 类增量学习损失函数
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