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1.
Kidney Blood Press Res ; : 1-12, 2019 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-31487717

RESUMO

BACKGROUND/AIMS: Stress-induced cell senescence, which contributes to cell cycle arrest and is independent of age, plays an important role in chronic kidney disease (CKD) progression. DcR2, as a senescent marker, exclusively expressed in senescent tubular epithelia. The objective of this study was to examine whether urinary DcR2 (uDcR2) could be a potential biomarker for tubulointerstitial fibrosis (TIF) in patients with immunoglobulin A nephropathy (IgAN). METHODS: This study included 210 IgAN patients and 80 healthy volunteers, with uDcR2 levels measured using enzyme-linked immunosorbent assay. We examined the relationship among uDcR2/Cr levels, renal function, and pathological parameters, using regression analysis to identify risk factors for TIF and the area under the curve (AUC) approach to predict TIF. Renal DcR2 expression was quantified by immunohistochemistry. Co-expression of DcR2 with fibrotic markers (α-smooth muscle actin [α-SMA], collagen III) was analyzed by confocal microscopy. RESULTS: Levels of uDcR2/Cr were significantly higher in IgAN patients and in those with more severe TIF, compared with healthy controls. Serum DcR2 levels were similar across groups. The proportion of IgAN patients with stages 1-2 CKD and T0 was highest among those with uDcR2/Cr <130 ng/g. In contrast, the majority of those with uDcR2/Cr >201 ng/g had stages 4-5 CKD and T2. Levels of uDcR2/Cr were positively associated with urinary albumin to creatinine ratio (ACR), urinary N-acetyl-ß-D-glucosaminidase (uNAG)/Cr, and TIF scores and negatively associated with estimated glomerular filtration rate (eGFR). uDcR2/Cr, uNAG, ACR, and eGFR were independent predictors for TIF, with AUC of 0.907 for uDcR2/Cr. This AUC value was higher than that observed for eGFR, uNAG/Cr, or ACR. The sensitivity and specificity of uDcR2/Cr in predicting TIF were 87.0 and 80.5%, respectively. Moreover, uDcR2/Cr levels were positively associated with the percentage of renal DcR2 expression. Renal DcR2 co-localized with α-SMA and collagen III in the kidneys of IgAN patients. CONCLUSIONS: Levels of uDcR2/Cr were closely associated with the severity of TIF and renal function parameters. uDcR2/Cr represents a potential biomarker for predicting TIF in IgAN patients.

3.
Mol Genet Genomics ; 2019 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-31489484

RESUMO

Regulatory factors function by modulating a variety of cascade mechanisms in cells. RBM4 is a multifunctional RNA-binding protein in post-transcriptional gene regulation. Cytoplasmic RBM4 interacts with Ago2 to regulate inflammatory responses by affecting mRNA decay and cap-dependent translation. However, it is unclear whether RBM4 functions in inflammation regulation by its splicing factor role. Here, the cell biology, gene expression profile and alternative splicing pattern of HeLa cells with RBM4 overexpression (RBM-OE) were compared with the control. The results showed that RBM4-OE inhibited proliferation. RBM4-OE extensively affects the transcriptional level of genes involved in cell surface receptor signalling pathway, inflammatory responses and the response to lipopolysaccharide. RBM4 broadly regulated the alternative splicing of hundreds of genes with functions of protein binding, helicase activity, DNA binding and transcription co-activator. RBM4-regulated splicing of these genes plays an important role in apoptotic process and gene transcription regulation. As an example, exon inclusion of TNIP1 mediated by RBM4 affects the expression of its targets in inflammatory pathways. These results indicated that RBM4 can mediate the inflammatory response via splicing regulation, which adds to the understanding of the critical role of RBM4 in cancer complicated by inflammation. In conclusion, this study indicated a mechanism in which the dysregulation of alternative splicing can influence cellular biology and lead to various immune-related diseases.

4.
J Pharm Biomed Anal ; 177: 112837, 2019 Aug 26.
Artigo em Inglês | MEDLINE | ID: mdl-31493746

RESUMO

The ambiguity of dose-effect relationship of many traditional Chinese medicines (TCMs) has always influenced their rational use in TCM clinic. Rhubarb, a preferred representative of cathartic TCM, is currently widely used that results in a diversity of its dosage. The aim of this study was to use an integrated metabolomics strategy to simultaneously reveal dose-effect relationship and therapeutic mechanisms of different efficacy of rhubarb in constipation rats. Six doses of rhubarb (0.135, 0.27, 0.81, 1.35, 4.05, and 8.1 g/kg) were examined to elucidate the laxative and fire-purging effects by pathological sections and UPLC-Q-TOF/MSE. The results showed that there existed serious lesions in the stomach and colon of model rats. And conditions were basically improved to some extent in rhubarb-treated groups. Through relative distance calculation based on metabolomics score plots, it suggested that the effective dose threshold (EC20-EC80 range) of rhubarb was from 0.31 to 4.5 g/kg (corresponding to 3.44-50.00 g in the clinic) in rat serum and 0.29-2.1 g/kg (corresponding to 3.22-23.33 g in the clinic) in feces. Then, 33 potential biomarkers were identified in total. Functional pathway analysis revealed that the alterations of these biomarkers were associated with 15 metabolic pathways, mainly including arachidonic acid metabolism, glycerophospholipid metabolism, steroid biosynthesis, primary bile acid biosynthesis and sphingolipid metabolism. Of note, different doses of rhubarb could alleviate endogenous disorders to varying degrees through regulating multiple perturbed pathways to the normal state, which might be in a dose-dependent manner and involved in therapeutic mechanisms. To sum up, integrated serum and fecal metabolomics obtained that rhubarb ranging from 0.31 to 2.1 g/kg is safe and effective for constipation treatment. Also, our findings showed that the robust metabolomics techniques would be promising to be more accurately used in the dose-effect studies of complex TCM, and to clarify syndrome pathogenesis and action mechanisms in Chinese medicine.

5.
Chin J Nat Med ; 17(7): 490-497, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31514980

RESUMO

Current study systematically investigated the interaction of two alkaloids, anisodine and monocrotaline, with organic cation transporter OCT1, 2, 3, MATE1 and MATE2-K by using in vitro stably transfected HEK293 cells. Both anisodine and monocrotaline inhibited the OCTs and MATE transporters. The lowest IC50 was 12.9 µmol·L-1 of anisodine on OCT1 and the highest was 1.8 mmol·L-1 of monocrotaline on OCT2. Anisodine was a substrate of OCT2 (Km = 13.3 ± 2.6 µmol·L-1 and Vmax = 286.8 ± 53.6 pmol/mg protein/min). Monocrotaline was determined to be a substrate of both OCT1 (Km = 109.1 ± 17.8 µmol·L-1, Vmax = 576.5 ± 87.5 pmol/mg protein/min) and OCT2 (Km = 64.7 ± 14.8 µmol·L-1, Vmax = 180.7 ± 22.0 pmol/mg protein/min), other than OCT3 and MATE transporters. The results indicated that OCT2 may be important for renal elimination of anisodine and OCT1 was responsible for monocrotaline uptake into liver. However neither MATE1 nor MATE2-K could facilitate transcellular transport of anisodine and monocrotaline. Accumulation of these drugs in the organs with high OCT1 expression (liver) and OCT2 expression (kidney) may be expected.

6.
J Nutr Biochem ; 72: 108219, 2019 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-31473507

RESUMO

Epithelial-mesenchymal transition (EMT) contributes to the initiation, invasion, metastasis and drug resistance of cancer. The function of extracellular signal-regulated kinase 5 (ERK5) in lung cancer progression remains elusive. In this study, we investigated the effect of sulforaphane (SFN) on lung cancer EMT and the role of ERK5 in its effect. Wound healing and Transwell assays were applied to examine the migratory and invasive capacity in vitro. Quantitative real-time polymerase chain reaction and immunoblotting analysis were performed to investigate the expression of mRNA and protein levels. Small-interfering RNA was used to silence ERK5. Xenograft model was used to confirm the effect of SFN in vivo. Enhanced EMT and decreased ERK5 activation were observed in lung cancer cells in comparison with normal human bronchial epithelial cells. SFN diminished the migratory and invasive capacity of lung cancer cells. Additionally, significantly increased expression of epithelial markers (E-cadherin and ZO-1), decreased expression of mesenchymal markers (N-cadherin and Snail1) and activation of ERK5 were observed after SFN treatment. The inhibitory effect of SFN on lung cancer cell EMT was attenuated by ERK5 silencing. SFN-induced EMT suppression and ERK5 activation were further confirmed in lung cancer xenograft mouse model. The present study illustrated for the first time that ERK5 activation mediates SFN suppression of lung cancer cell EMT. These findings could provide new insights into the function of ERK5 in EMT regulation and the potential therapeutic application of SFN in cancer intervention.

7.
J Formos Med Assoc ; 2019 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-31477483

RESUMO

BACKGROUND/PURPOSE: Birth defects (BDs) are main causes of mortality and disability in infants and children. The aims of this study were to analyze the prevalence, types and risk factors of BDs in Taiwan. METHODS: Data of all births (including live and stillbirths), types, characteristics, and associated risk factors of BDs were obtained from the National Birth Registry and National Health Insurance Research Data base in Taiwan between 2005 and 2014. Birth defects were coded according to International Classification of Diseases 9th Revision-Clinical Modification codes 740-759. RESULTS: A total of 55,299 infants were diagnosed as having BDs among 2,033,004 births. The prevalence of BDs was 271.66 per 10,000 births. The prevalence of BDs did not change significantly between 2005 and 2014, there was a higher birth rate and lower BDs in 2012 (year of dragon) in Taiwan. The most common type of BDs was cardiovascular abnormalities, and ventricular septal defect was the most common disease. Extreme maternal age (<18 years or ≧30 years), preterm, and low birth weight were associated with BDs. Maternal diseases associated with BDs included hypertension, cardiovascular diseases, renal diseases, genitourinary infections, anemia, mental disorders, and diabetes mellitus. CONCLUSION: The prevalence of BDs was 271.66 per 10,000 births. The most common types of BDs were cardiovascular abnormalities. If we can reduce maternal chronic diseases, we will decrease the prevalence of BDs.

8.
J Vis Exp ; (150)2019 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-31498306

RESUMO

Aberrant changes in endothelial phenotype and morphology are considered to be initial events in the pathogenesis of atherosclerosis. Direct observation of the intact endothelium will provide valuable information for understanding the cellular and molecular events in the dysfunctional endothelial cells. Here, we describe a modified en face immunofluorescence staining technique which enables scientists to obtain clear images of the intact endothelial surface and analyze the molecule expression patterns in situ. The method is simple and reliable for observing the entire endothelial monolayer at different sites of the aorta. This technique may be a promising tool for understanding the pathophysiology of atherosclerosis, especially at an early stage.

10.
Cancer ; 2019 Aug 12.
Artigo em Inglês | MEDLINE | ID: mdl-31402456

RESUMO

BACKGROUND: The authors hypothesized that epigenetic changes may help to clarify the underlying biologic mechanism linking aspirin use to breast cancer prognosis. To the authors' knowledge, this is the first epidemiologic study to examine whether global methylation and/or tumor promoter methylation of breast cancer-related genes interact with aspirin use to impact mortality after breast cancer. METHODS: Prediagnosis aspirin use was assessed through in-person interviews within a population-based cohort of 1508 women diagnosed with a first primary breast cancer in 1996 and 1997. Global methylation in peripheral blood was assessed by long interspersed elements-1 (LINE-1) and the luminometric methylation assay. Promoter methylation of 13 breast cancer-related genes was measured in tumor by methylation-specific polymerase chain reaction and the MethyLight assay. Vital status was determined by the National Death Index through December 31, 2014 (N = 202/476 breast cancer-specific/all-cause deaths identified among 1266 women with any methylation assessment and complete aspirin data). Cox proportional hazards regression was used to estimate hazard ratios (HRs) and 95% CIs, and the likelihood ratio test was used to evaluate multiplicative interactions. RESULTS: All-cause mortality was elevated among aspirin users who had methylated promotor of BRCA1 (HR, 1.67; 95% CI, 1.26-2.22), but not among those with unmethylated promoter of BRCA1 (HR, 0.99; 95% CI, 0.67-1.45; P for interaction ≤.05). Decreased breast cancer-specific mortality was observed among aspirin users who had unmethylated promotor of BRCA1 and PR and global hypermethylation of LINE-1 (HR, 0.60, 0.78, and 0.63, respectively; P for interaction ≤.05), although the 95% CIs included the null. CONCLUSIONS: The current study suggests that the LINE-1 global methylation and promoter methylation of BRCA1 and PR in tumor may interact with aspirin use to influence mortality after breast cancer.

11.
Epigenetics ; : 1-14, 2019 Aug 12.
Artigo em Inglês | MEDLINE | ID: mdl-31403346

RESUMO

Imprinted genes play a pivotal role in placental processes underlying fetal development, and much interest centers on discerning whether these loci, via changes in DNA methylation and/or gene expression, inform disruptions in appropriate fetal growth. In this study, we comprehensively profiled DNA methylation across the placental imprintome and assessed the relationship with gene expression levels and aberrant fetal growth. Placental DNA methylation across 153 imprinted loci, including imprint control regions (ICR) and surrounding non-ICR regions, was surveyed using the Nimblegen TruSeq bisulfite sequencing platform among participants enrolled in the Rhode Island Child Health Study (RICHS, n = 163). Methylation and gene expression associations were assessed using eQTM analysis. Differential methylation analysis contrasting small (SGA) and large for gestational age (LGA) infants against appropriate for gestational age (AGA) infants was assessed using the DMRcate R package. We identified 34 SGA-related differentially methylated regions (DMRs) and 9 LGA-related DMRs (FDR<0.05), and these BW-DMRs predominated in promoter and intronic regions. We observed overall hypomethylation among SGA-DMRs overlapping maternally expressed (paternally imprinted) genes while no parent-of-origin effect was observed among LGA DMRs. Three BW-DMRs, mapping to GABRG3, IGF1R and MEST, were common to SGA and LGA placenta. We did not observe significant correlations between BW-DMR-associated CpG methylation and gene expression levels. We report the first in-depth characterization of the placental imprintome in a population-wide setting. Our findings reveal growth-related differences in methylation without concomitant expression differences in regions that extend beyond typically interrogated imprinted loci, highlighting potentially novel placental biomarkers of growth and development.

12.
J Transl Med ; 17(1): 276, 2019 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-31429774

RESUMO

BACKGROUND: Mast cell activation causes degranulation and release of cytokines, thereby promoting inflammation. The aim of this study was to investigate the inhibitory effect of CDK4/6 inhibition on mast cell activation in vitro and in vivo. METHODS: RBL-2H3 rat basophilic leukemia cells (BLCs) and mouse bone marrow-derived mast cells (BMMCs) were sensitized with anti-dinitrophenol (DNP) immunoglobulin (Ig)E antibodies, stimulated with DNP-human serum albumin (HSA) antigens, and treated with the CDK4/6 inhibitor palbociclib. Histological stains were applied to reveal cytomorphological changes. Murine IgE-mediated passive cutaneous anaphylaxis (PCA) and ovalbumin (OVA)-induced active systemic anaphylaxis (ASA) models were used to examine palbociclib effects on allergic reactions in vivo. Western blots were performed to detect the expression of cell signaling molecules associated with mast cell activation. RESULTS: Activated BLCs and BMMCs released copious granule-related mediators (histamine and ß-hexosaminidase), which was reduced by palbociclib in a concentration-dependent manner. Palbociclib inhibited expression of the mast cell activation marker CD63 in activated BLCs and inhibited granule release (visualized with toluidine blue staining) while preventing morphological changes, (elongated shape maintained) and filamentous actin (F-actin) reorganization. Palbociclib suppressed molecular Lyn and/or mitogen-activated protein kinase (MAPK) signaling associated with mast cell activation in stimulated BLCs and attenuated allergic reactions in PCA mice dose dependently. Palbociclib attenuated body temperature reduction and diminished serum histamine levels in ovalbumin OVA-challenged ASA mice. CONCLUSION: Palbociclib suppresses IgE-mediated mast cell activation in vitro and in vivo, suggesting that it may be developed into a therapy for mast cell-mediated allergic diseases via inhibition of mast cell degranulation.

13.
Viruses ; 11(9)2019 Aug 25.
Artigo em Inglês | MEDLINE | ID: mdl-31450668

RESUMO

The severe strain of citrus tristeza virus (CTV) causes quick decline of citrus trees. However, the CTV mild strain causes no symptoms and commonly presents in citrus trees. Viral suppressor of RNA silencing (VSR) plays an important role in the successful invasion of viruses into plants. For CTV, VSR has mostly been studied in severe strains. In this study, the N4 mild strain in China was sequenced and found to have high sequence identity with the T30 strain. Furthermore, we verified the functions of three VSRs in the N4 strain, and p23 was found to be the most effective in terms of local silencing suppressor activity among the three CTV VSRs and localized to both nucleus and plasmodesmata, which is similar to CTV T36 strain. Several conserved amino acids were identified in p23. Mutation of E95A/V96A and M99A/L100AA impaired p23 protein stability. Consequently, these two mutants lost most of its suppressor activity and their protein levels could not be rescued by co-expressing p19. Q93A and R143A/E144A abolished p23 suppressor activity only and their protein levels increased to wild type level when co-expressed with p19. This work may facilitate a better understanding of the pathogenic mechanism of CTV mild strains.

14.
Head Neck ; 2019 Aug 22.
Artigo em Inglês | MEDLINE | ID: mdl-31435974

RESUMO

BACKGROUND: The study was aimed to evaluate the impact of accumulated oral tegafur-uracil (UFUR) as maintenance chemotherapy on overall survival (OS) and disease-free survival (DFS) rates after concurrent chemoradiotherapy (CCRT) for complete remission (CR) in non-distant metastatic TNM stage IV nasopharyngeal carcinoma (NPC). METHODS: Data were retrospectively analyzed from a database of patients with non-distant metastatic TNM stage IV NPC, composed of those who underwent CCRT for CR from January 2010 through December 2017. RESULTS: Thirty-three patients were treated with CCRT (the non-UFUR group), and the other 37 patients were treated with the same regimen, followed by additional oral UFUR (the UFUR group). Importantly, the 5-year OS rates were 91.89% in the UFUR group and 57.58% in the non-UFUR group (P = .004). CONCLUSIONS: Adding UFUR to CCRT was found to significantly improve the DFS and OS rates of patients with non-distant metastatic TNM stage IV NPC. The authors cautiously suggest UFUR as possible maintenance therapy following CCRT.

15.
Org Lett ; 2019 Aug 22.
Artigo em Inglês | MEDLINE | ID: mdl-31436103

RESUMO

A light-driven, metal-free, and iminyl radical-mediated ring-opening C-C bond cleavage/addition cascade of O-4-methoxybenzyl oxime ethers and alkenes is described for the first time. The reaction shows a broad substrate scope and high functional group compatibility with both components, giving the corresponding valuable oxo nitriles in generally good yields. Key to the success of this protocol is the generation of cyclic iminyl radicals from the O-4-methoxybenzyl oxime ethers via a photocatalytic hydrogen atom transfer (HAT) process. The proposed main pathway is also supported by the preliminary mechanistic studies.

16.
Adv Virus Res ; 104: 313-343, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31439152

RESUMO

The prototypical human γ-herpesviruses Epstein-Barr virus (EBV) and Kaposi Sarcoma-associated herpesvirus (KSHV) are involved in the development of malignancies. Like all herpesviruses, they share the establishment of latency, the typical architecture, and the conserved fusion machinery to initiate infection. The fusion machinery reflects virus-specific adaptations due to the requirements of the respective herpesvirus. For example, EBV evolved a tropism switch involving either the B- or epithelial cell-tropism complexes to activate fusion driven by gB. Most of the EBV entry proteins and their cellular receptors have been crystallized providing molecular details of the initial steps of infection. For KSHV, a variety of entry and binding receptors has also been reported but the mechanism how receptor binding activates gB-driven fusion is not as well understood as that for EBV. However, the downstream signaling pathways that promote the early steps of KSHV entry are well described. This review summarizes the current knowledge of the key players involved in EBV and KSHV entry and the cell-type specific mechanisms that allow infection of a wide variety of cell types.

17.
BMC Complement Altern Med ; 19(1): 215, 2019 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-31412844

RESUMO

BACKGROUND: Mounting evidence indicates that the cerebral cortex is an important physiological system of emotional activity, and its dysfunction may be the main cause of stress. Glutamate is the primary excitatory neurotransmitter in the central nervous system (CNS), which initiates rapid signal transmission in the synapse before its reuptake into the surrounding glia, specifically astrocytes (ASTs). The astrocytic excitatory amino acid transporters 1 (EAAT1) and 2 (EAAT2) are the major transporters that take up synaptic glutamate to maintain optimal extracellular glutamic levels, thus preventing accumulation in the synaptic cleft and ensuing excitotoxicity. Growing evidence has shown that excitotoxicity is associated with depression. Therefore, we hypothesized that the underlying antidepressant-like mechanism of Xiaoyaosan (XYS), a Chinese herbal formula, may be related to the regulation of astrocytic EAATs. Therefore, we studied the antidepressant mechanism of XYS on the basis of EAAT dysfunction in ASTs. METHODS: Eighty adult C57BL/6 J mice were randomly divided into 4 groups: a control group, a chronic unpredictable mild stress (CUMS) group, a Xiaoyaosan (XYS) treatment group and a fluoxetine hydrochloride (Flu) treatment group. Except for the control group, mice in the other groups all received chronic unpredictable mild stress for 21 days. Mice in the control and CUMS groups received gavage administration with 0.5 mL of normal saline (NS) for 21 days, and mice in the XYS and Flu treatment groups were administered dosages of 0.25 g/kg/d and 2.6 mg/kg/d by gavage. The effects of XYS on the depressive-like behavioral tests, including the open field test (OFT), forced swimming test (FST) and sucrose preference test (SPT), were examined. The glutamate (Glu) concentrations of the prefrontal cortex (PFC) were detected with colorimetry. The morphology of neurons in the PFC was observed by Nissl staining. The expression of glial fibrillary acidic protein (GFAP), NeuN, EAAT1 and EAAT2 proteins in the PFC of mice was detected by using Western blotting and immunohistochemistry. Quantitative real-time PCR (qPCR) was used to detect the expression of the GFAP, NeuN, EAAT1 and EAAT2 genes in the PFC of mice. RESULTS: The results of behavioral tests showed that CUMS-induced mice exhibited depressive-like behavior, which could be improved in some tests with XYS and Flu treatment. Immunohistochemistry and Western blot analysis showed that the protein levels of GFAP, NeuN, EAAT1 and EAAT2 in the PFC of CUMS mice were significantly lower than those in the control group, and these changes could be reversed by XYS and Flu. The results of qPCR analysis showed that the expression of GFAP, NeuN, EAAT1 and EAAT2 mRNAs in the PFC of CUMS mice was not significantly changed, with the exception of EAAT2, compared with that of the control group, while the expression of the above mRNAs was significantly higher in the XYS and Flu groups than that in the CUMS group. CONCLUSION: XYS may exert antidepressant-like effects by improving the functions of AST and EAATs and attenuating glutamate-induced neuronal damage in the frontal cortex.

18.
IEEE Trans Cybern ; 2019 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-31425063

RESUMO

Ensemble learning performs better than a single classifier in most tasks due to the diversity among multiple classifiers. However, the enhancement of the diversity is at the expense of reducing the accuracies of individual classifiers in general and, thus, how to balance the diversity and accuracies is crucial for improving the ensemble performance. In this paper, we propose a new ensemble method which exploits the correlation between individual classifiers and their corresponding weights by constructing a joint optimization model to achieve the tradeoff between the diversity and the accuracy. Specifically, the proposed framework can be modeled as a shallow network and efficiently trained by the end-to-end manner. In the proposed ensemble method, not only can a high total classification performance be achieved by the weighted classifiers but also the individual classifier can be updated based on the error of the optimized weighted classifiers ensemble. Furthermore, the sparsity constraint is imposed on the weight to enforce that partial individual classifiers are selected for final classification. Finally, the experimental results on the UCI datasets demonstrate that the proposed method effectively improves the performance of classification compared with relevant existing ensemble methods.

20.
Nanoscale ; 2019 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-31461106

RESUMO

The practical application of optoelectronic artificial synapses in neuromorphic visual systems is still hindered by their limited functionality, reliability and the challenge of mass production. Here, an electro-photo-sensitive synapse based on a highly reliable amorphous InGaZnO thin-film transistor is demonstrated. Not only does the synapse respond to electrical voltage spikes due to charge trapping/detrapping, but also the weight is modified directly by persistent photocurrent effects under UV-light stimulation. Representative forms of synaptic plasticity, including inhibitory and excitatory postsynaptic currents, frequency-dependent characteristics, short-term to long-term plasticity transitions, and summation effects, are successfully demonstrated. In particular, optoelectronic synergetic modulation leads to reconfigurable excitatory and inhibitory synaptic behaviors, which provides a promising way to achieve the homeostatic regulation of synaptic weights. Moreover, the analogue channel conductance with 100 states is used as the weight update rule to perform MNIST handwritten digit recognition, using system-level LeNet-5 convolutional neural network simulations. The network shows a high recognition accuracy of 95.99% and good tolerance to noisy input patterns. This study highlights the commercial potential of mature optoelectronic InGaZnO transistor technology in edge neuromorphic systems.

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