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Nanoscale resistive switching devices for memory and computing applications

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Nano research 2020年第5期13卷 1228-1243页

作者： Seung Hwan Lee Xiaojian Zhu Wei D.Lu Department of electrical Engineering and Computer Science The University of MichiganAnn ArborMichigan 48109USA

With the slowing down of the Moore’s law and fundamental limitations due to the von-Neumann bottleneck,continued improvements in computing hardware performance become increasingly more *** switching(RS)devices are being extensively studied as promising candidates for next generation memory and computing applications due to their fast switching speed,excellent endurance and retention,and scaling and three-dimensional(3D)stacking *** particular,RS devices offer the potential to natively emulate the functions and structures of synapses and neurons,allowing them to efficiently implement neural networks(NNs)and other in-memory computing systems for data intensive applications such as machine learning *** this review,we will examine the mechanisms of RS effects and discuss recent progresses in the application of RS devices for memory,deep learning accelerator,and more faithful brain-inspired computing *** and possible solutions at the device,algorithm,and system levels will also be discussed.

关键词： resistive switching oxygen vacancy metal cation memory application in-memory computing bio-inspired application

Automated Exudates Detection in retinal Fundus Image Using Morphological Operator and Entropy Maximization Thresholding

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Journal of Biomedical Science and Engineering 2019年第3期12卷 212-224页

作者： G. H. Kom B. C. Wouantsa Tindo J. R. Mboupda Pone A. B. Tiedeu research Unit of Automation and Applied Informatics (URAIA) Department of Electrical Engineering IUT-FV Bandjoun University of Dschang Bandjoun Cameroon research group on Medical Technologies Applied to the Tropics (GRETMAT) Laboratory of Electronics and Signal Processing (LETS) ENSP University of Yaoundé I Yaoundé Cameroon research Unit for Condensed Matter Electronics and Signal Processing (LAMACETS) Department of Physics University of Dschang Dschang Cameroon Signal Image and Systems Laboratory Ebolowa Cameroon

Blindness which is considered as degrading disabling disease is the final stage that occurs when a certain threshold of visual acuity is overlapped. It happens with vision deficiencies that are pathologic states due to many ocular diseases. Among them, diabetic retinopathy is nowadays a chronic disease that attacks most of diabetic patients. Early detection through automatic screening programs reduces considerably expansion of the disease. Exudates are one of the earliest signs. This paper presents an automated method for exudates detection in digital retinal fundus image. The first step consists of image enhancement. It focuses on histogram expansion and median filter. The difference between filtered image and his inverse reduces noise and removes background while preserving features and patterns related to the exudates. The second step refers to blood vessel removal by using morphological operators. In the last step, we compute the result image with an algorithm based on Entropy Maximization Thresholding to obtain two segmented regions (optical disk and exudates) which were highlighted in the second step. Finally, according to size criteria, we eliminate the other regions obtain the regions of interest related to exudates. Evaluations were done with retinal fundus image DIARETDB1 database. DIARETDB1 gathers high-quality medical images which have been verified by experts. It consists of around 89 colour fundus images of which 84 contain at least mild non-proliferative signs of the diabetic retinopathy. This tool provides a unified framework for benchmarking the methods, but also points out clear deficiencies in the current practice in the method development. Comparing to other recent methods available in literature, we found that the proposed algorithm accomplished better result in terms of sensibility (94.27%) and specificity (97.63%).

关键词： Diabetic Retinopathy retinal Fundus Image Exudates Entropy Maximization Thresholding

Transfer Learning-based Computer-aided Diagnosis System for Predicting Grades of Diabetic Retinopathy

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Computers, Materials & Continua 2022年第6期71卷 4573-4590页

作者： Qaisar Abbas Mostafa E.A.Ibrahim Abdul Rauf Baig College of Computer and Information Sciences Imam Mohammad Ibn Saud Islamic University(IMSIU)Riyadh11432Saudi Arabia Department of electrical Engineering Benha Faculty of EngineeringBenha UniversityQalubiaBenha13518Egypt

Diabetic retinopathy(DR)diagnosis through digital fundus images requires clinical experts to recognize the presence and importance of many intricate *** task is very difficult for ophthalmologists and ***,many computer-aided diagnosis(CAD)systems were developed to automate this screening process *** this paper,aCAD-DR system is proposed based on preprocessing and a pre-train transfer learningbased convolutional neural network(PCNN)to recognize the five stages of DR through retinal fundus *** develop this CAD-DR system,a preprocessing step is performed in a perceptual-oriented color space to enhance the DR-related lesions and then a standard pre-train PCNN model is improved to get high classification *** architecture of the PCNN model is based on three main ***,the training process of the proposed PCNN is accomplished by using the expected gradient length(EGL)to decrease the image labeling efforts during the training of the CNN ***,themost informative patches and images were automatically selected using a few pieces of training labeled ***,the PCNN method generated useful masks for prognostication and identified regions of ***,the DR-related lesions involved in the classification task such as micro-aneurysms,hemorrhages,and exudates were detected and then used for recognition of *** PCNN model is pre-trained using a high-end graphical processor unit(GPU)on the publicly available Kaggle *** obtained results demonstrate that the CAD-DR system outperforms compared to other state-of-the-art in terms of sensitivity(SE),specificity(SP),and accuracy(ACC).On the test set of 30,000 images,the CAD-DR system achieved an average SE of 93.20%,SP of 96.10%,and ACC of 98%.This result indicates that the proposed CAD-DR system is appropriate for the screening of the severity-level of DR.

关键词： Diabetic Retinopathy retinal fundus images computer-aided diagnosis system deep learning transfer learning convolutional neural network

Knockdown of fibrillin-1 suppresses retina-blood barrier dysfunction by inhibiting vascular endothelial apoptosis under diabetic conditions

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International Journal of Ophthalmology(English edition) 2024年第8期17卷 1403-1410页

作者： Yue Zhang Xiao-Jing Liu Xin-Ran Zhai Yao Yao Bin Shao Yu-Han Zhen Xin Zhang Zhe Xiao Li-Fang Wang Ming-Lian Zhang Zhi-Min Chen Hebei Eye Hospital Provincial Key Laboratory of OphthalmologyHebei Provincial Clinical Research Center for Eye DiseasesXingtai 054001Hebei ProvinceChina Department of Ophthalmology Hebei Medical UniversityShijiazhuang 050011Hebei ProvinceChina

AIM:To investigate the effects of fibrillin-1(FBN1)deletion on the integrity of retina-blood barrier function and the apoptosis of vascular endothelial cells under diabetic ***:Streptozotocin(STZ)-induced diabetic mice were used to simulate the diabetic conditions of diabetic retinopathy(DR)patients,and FBN1 expression was detected in retinas from STZ-diabetic mice and *** the Gene Expression Omnibus(GEO)database,the GSE60436 dataset was selected to analyze FBN1 expressions in fibrovascular membranes from DR *** lentivirus to knock down FBN1 levels,vascular leakage and endothelial barrier integrity were detected by Evans blue vascular permeability assay,fluorescein fundus angiography(FFA)and immunofluorescence labeled with tight junction marker in *** glucose-induced monkey retinal vascular endothelial cells(RF/6A)were used to investigate effects of FBN1 on the cells in *** vascular endothelial barrier integrity and apoptosis were detected by trans-endothelial electrical resistance(TEER)assay and flow cytometry,***:FBN1 mRNA expression was increased in retinas of STZ-induced diabetic mice and fibrovascular membranes of DR patients(GSE60436 datasets)using RNA-seq ***,knocking down of FBN1 by lentivirus intravitreal injection significantly inhibited the vascular leakage compared to STZ-DR group by Evans blue vascular permeability assay and FFA *** of tight junction markers in STZ-DR mouse retinas were lower than those in the control group,and knocking down of FBN1 increased the tight junction *** vitro,30 mmol/L glucose could significantly inhibit viability of RF/6A cells,and FBN1 mRNA expression was increased under 30 mmol/L glucose ***-regulation of FBN1 reduced high glucose(HG)-stimulated retinal microvascular endothelial cell permeability,increased TEER,and inhibited RF/6A cell apoptosis in ***:The expression level of FBN1 increases in reti

关键词： diabetic retinopathy fibrillin-1 retinablood barrier vascular leakage vascular permeability apoptosis retinal vascular endothelial cells

Reduced macular inner retinal thickness and microvascular density in the early stage of patients with dysthyroid optic neuropathy

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Eye and Vision 2020年第2期7卷 150-161页

作者： Yufei Wu Yunhai Tu Chaoming Wu Lulu Bao Jianhua Wang Fan Lu Meixiao Shen Qi Chen School of Ophthalmology and Optometry Wenzhou Medical University270 Xueyuan RoadWenzhou 325027ZhejiangChina Department of Ophthalmology Yinzhou Hospital Affiliated to Medical School of Ningbo UniversityNingboZhejiangChina The Second Affiliated Hospital&Yuying Children’s Hospital of Wenzhou Medical University WenzhouZhejiangChina Bascom Palmer Eye Institute University of Miami Miller School of MedicineMiamiFLUSA electrical and Computer Engineering University of MiamiMiamiFLUSA

Background:The goal was to investigate changes of the inner intra-retinal layer thicknesses and retinal capillary density(RCD)around the macula in thyroid-associated ophthalmopathy(TAO)patients with or without dysthyroid optic neuropathy(DON).Methods:Forty-four TAO patients including 23 non-DON and 21 DON patients,and 38 healthy participants were *** domain optical coherence tomography equipped with Angiovue was used to obtain threedimensional retinal thickness maps and microvascular images of the superficial and deep retinal capillary layers(SRCL and DRCL,respectively)around the *** analyses were performed using a custom automated ***:The thicknesses of the nerve fiber layer,ganglion cell layer+inner plexiform layer,and ganglion cell complex(GCC)as well as the RCDs in the SRCL and DRCL in both TAO groups were significantly decreased compared to the *** addition,the RCDs in DRCL of the DON group were further decreased compared to the non-DON *** thickness in both TAO groups was positively correlated with the RCDs of the SRCL in the total annular zone and in the temporal,inferior,and nasal *** areas under the receiver operating characteristic curves for the GCC thickness combined with the RCD were generally larger than those of each single ***:Thinned inner intra-retinal layers and decreased RCDs in the TAO patients without DON revealed that morphological changes might precede visual *** composite index of the retinal structure and the microvascular density might be valuable in the diagnosing,monitoring,and intervention for early DON.

关键词： Retina Microvasculature Density Optical coherence tomography angiography Thyroid-associated ophthalmopathy

Associated risk factors in the early stage of diabetic retinopathy

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Eye and Vision 2019年第1期6卷 191-200页

作者： Fan Tan Qi Chen Xiran Zhuang Chaoming Wu Yanying Qian Yuanyuan Wang Jianhua Wang Fan Lu Meixiao Shen Yingzi Li School of Ophthalmology and Optometry Wenzhou Medical University270 Xueyuan RoadWenzhouZhejiangChina325027 Department of Ophthalmology West China-Guang’an HospitalSichuan UniversityGuang’anSichuanChina Department of Ophthalmology Sichuan University West China HospitalChengduSichuanChina The Second Affiliated Hospital&Yuying Children’s Hospital of Wenzhou Medical University WenzhouZhejiangChina Bascom Palmer Eye Institute University of Miami Miller School of MedicineMiamiFLUSA electrical and Computer Engineering University of MiamiMiamiFLUSA

Background:To investigate the retinal capillary density(RCD)of the macula using optical coherence tomography angiography(OCT-A)in type 2 diabetic patients and to further determine the association with risk ***:A total of 212 eyes from 212 subjects were recruited;subjects included diabetics with no retinopathy(NDR,n=90 eyes),diabetics with mild retinopathy DR(MDR,n=36 eyes),and healthy participants(Control,n=86 eyes).All participants underwent OCT-A *** was quantified by superficial and deep retinal capillary layers(SRCL and DRCL)from OCT-A ***:RCD in SRCL and DRCL was lower in NDR(P55y,HbA1c>7%had significantly reduced DRCL(Pgroup of diabetics(age8.2 mmol/L had significantly reduced SRCL and DRCL when compared to the other group of ***:Risk factors including older age,higher level of HbA1c,LDL-C and BUN,were associated with lower RCDs found in type 2 diabetic patients with and without mild DR by *** impairment of retinal capillary by OCT-A may play a key role in the early monitoring of management in diabetes.

关键词： Diabetic retinopathy Optical coherence tomography angiography retinal capillary density Systematic risk factors

Systemic epigallocatechin gallate protects against retinal degeneration and hepatic oxidative stress in the P23H-1 rat

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Neural Regeneration research 2022年第3期17卷 625-631页

作者： Lorena Perdices Lorena Fuentes-Broto Francisco Segura Ana Cavero Elvira Orduna-Hospital Gema Insa-Sánchez Ana Isabel Sánchez-Cano Laura Fernández-Sánchez Nicolás Cuenca Isabel Pinilla Aragón Institute for Health research(IIS Aragón) ZaragozaSpain Pharmacology Physiology&Legal and Forensic MedicineUniversity of ZaragozaZaragozaSpain Department of Applied Physics University of ZaragozaZaragozaSpain Health Sciences Faculty San Jorge UniversityVillanueva de GállegoSpain Department of Ophthalmology Miguel Servet University HospitalZaragozaSpain Department of Physiology Genetics and MicrobiologyUniversity of AlicanteAlicanteSpain Department of Surgery Gynecology and ObstetricsUniversity of ZaragozaZaragozaSpain/Department of OphthalmologyLozano Blesa University HospitalZaragozaSpain

Retinitis pigmentosa(RP) is a group of inherited retinal disorders that lead to photoreceptor *** has been reported to be related to oxidative stress,autophagy,and inflammation.(-)-Epigallocatechin gallate(EGCG),the most abundant catechin-based flavonoid in green tea leaves,has significant antioxidant,anti-carcinogenic,antimicrobial,and neuroprotective ***,given its low molecular weight and hydrophilic properties,can cross the blood-retinal barrier and is able to reach different ocular tissues such as the lens,cornea,and *** has been shown to provide retinal protection against ischemia;sodium nitroprusside-,N-methyl-D-aspartate-,lipopolysaccharide-,light-,sodium iodate-,or H2 O2-induced damage and diabetic *** suggests that systemic EGCG administration has the potential to protect against retinal degenerative or neurodegenerative diseases such as *** aim of this work was to investigate whether EGCG can protect against RP progression in the animal P23 H line 1,the model of *** P23 H rats were crossed with pigmented Long Evans rats to produce offspring exhibiting the clinical features of *** P23 H rats were treated via intraperitoneal injection with saline or EGCG at a dose of 25 mg/kg every week from P100 to P160 and then compared to wild-type Long Evans *** treated with EGCG showed better visual and retinal electrical function with increased contrast sensitivity and b-wave values compared with those observed in P23 H rats treated with *** reduced lipid peroxidation and increased total antioxidant capacity and catalase and superoxide dismutase *** differences were observed in visual acuity,nitrate levels,nitrite levels or glutathione S-transferase *** conclusion,EGCG not only reduced the loss of visual function in P23 H rats but also improved the levels of antioxidant enzymes and reduced oxidative *** study was approved by the Institutional Animal Care and Use Committee(CE

关键词： antioxidants contrast sensitivity electroretinogram green tea neurodegeneration oxidative stress retinal degeneration retinitis pigmentosa systemic visual acuity

*** stress in glaucoma engages early activation of the energy biosensor adenosine monophosphate-activated protein kinase leading to neuronal dysfunction

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Annals of Eye Science 2018年第1期 421-421页

作者： Nicolas Belforte Jorge L.Cueva Vargas Adriana Di Polo Department of Neuroscience University of Montreal Hospital Research Center(CR-CHUM)MontrealQuebecCanada

Background:Metabolic stress has been proposed to contribute to neuronal damage in glaucoma,but the mechanism driving this response is not *** adenosine monophosphate-activated protein kinase(AMPK)is a master regulator of energy homeostasis that becomes active at the onset of energy *** is a potent inhibitor of the mammalian target of rapamycin complex 1(mTORC1),which we showed is essential for the maintenance of retinal ganglion cell(RGC)dendrites,synapses,and ***,we tested the hypothesis that AMPK is an early mediator of metabolic stress in ***:Unilateral elevation of intraocular pressure was induced by injection of magnetic microbeads into the anterior chamber of mice expressing yellow fluorescent protein in *** of AMPK was achieved by administration of siRNA or compound *** dendritic trees were 3D-reconstructed and analyzed with Imaris(Bitplane),and survival was assessed by counting Brn3a or RBPMS-labeled soma and axons in the optic *** function was examined by quantification of anterograde axonal transport after intraocular administration of cholera toxinβ-*** from glaucoma patients were analyzed for expression of active ***:Ocular hypertension triggered rapid upregulation of AMPK activity in RGCs concomitant with loss of mTORC1 *** inhibition with compound C or siRNA effectively restored mTORC1 activity and promoted an increase in total dendritic length,surface and complexity relative to control *** of AMPK activity led to robust RGC soma and axon *** example,95%of RGCs(2,983±258 RGCs/mm2,mean±S.E.M.)survived with compound C compared to 77%in vehicle-treated eyes(2,430±233 RGCs/mm2)(ANOVA,Pgroup).Importantly,blockade of AMPK activity effectively restored anterograde axonal ***,RGC-specific upregulation of AMPK activity was detected in human glaucomatous retinas relative to age-ma

关键词： Metabolic stress retinal ganglion cell(RGC) adenosine monophosphate-activated protein kinase(AMPK) glaucoma

Photonic synapses with ultralow energy consumption for artificial visual perception and brain storage

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Opto-Electronic Advances 2022年第9期5卷 1-13页

作者： Caihong Li Wen Du Yixuan Huang Jihua Zou Lingzhi Luo Song Sun Alexander OGovorov Jiang Wu Hongxing Xu Zhiming Wang Institute of Fundamental and Frontier Sciences University of Electronic Science and Technology of ChinaChengdu 610054China Microsystem and Terahertz research Center China Academy of Engineering PhysicsChengdu 610200China Institute of Electronic Engineering China Academy of Engineering PhysicsMianyang 621999China Department of Physics and Astronomy Ohio UniversityAthensOhio 45701United States State Key Laboratory of Electronic Thin Films and Integrated Devices University of Electronic Science and Technology of ChinaChengdu 610065China School of Physics and Technology Wuhan UniversityWuhan 430072China

The human visual system,dependent on retinal cells,can be regarded as a complex combination of optical system and nervous *** retinal system could mimic the sensing and processing function of human *** stimulated synaptic devices could serve as the building blocks for artificial retinas and subsequent information transmission system to ***,photonic synaptic transistors based on polycrystalline MoS_(2),which could simulate human visual perception and brain storage,are ***,the photodetection range from visible light to near-infrared light of MoS_(2) multilayer could extend human eyes’vision limitation to near-infrared ***,the photonic synaptic transistor shows an ultrafast speed within 5μs and ultralow power consumption under optical stimuli about 40 aJ,several orders of magnitude lower than biological synapses(50 ms and 10 fJ).Furthermore,the backgate control could act as emotional modulation of the artificial brain to enhance or suppress memory function,*** intensity of *** proposed carrier trapping/detrapping as the main working mechanism is presented for the *** addition,synaptic functionalities including short synaptic plasticity,long synaptic plasticity and paired-pulse facilitation could be successfully simulated based on the prepared ***,the large difference between short synaptic plasticity and long synaptic plasticity reveals the better image pre-processing function of the prepared photonic *** classical Pavlovian conditioning associated with the associative learning is successfully implemented as ***,the efficient and rich functionalities demonstrate the potential of the MoS_(2) synaptic device that integrates sensing-memory-preprocessing capabilities for realizing artificial neural networks with different emotions that mimic human retina and brain.

关键词： MoS_(2)synaptic transistors visual perception ultralow power consumption memory