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1.
Nat Commun ; 13(1): 6431, 2022 10 28.
Artículo en Inglés | MEDLINE | ID: mdl-36307483

RESUMEN

Neuromorphic computing, an alternative for von Neumann architecture, requires synapse devices where the data can be stored and computed in the same place. The three-terminal synapse device is attractive for neuromorphic computing due to its high stability and controllability. However, high nonlinearity on weight update, low dynamic range, and incompatibility with conventional CMOS systems have been reported as obstacles for large-scale crossbar arrays. Here, we propose the CMOS compatible gate injection-based field-effect transistor employing thermionic emission to enhance the linear conductance update. The dependence of the linearity on the conduction mechanism is examined by inserting an interfacial layer in the gate stack. To demonstrate the conduction mechanism, the gate current measurement is conducted under varying temperatures. The device based on thermionic emission achieves superior synaptic characteristics, leading to high performance on the artificial neural network simulation as 93.17% on the MNIST dataset.


Asunto(s)
Redes Neurales de la Computación , Sinapsis
2.
J Nat Prod ; 80(11): 3043-3048, 2017 11 22.
Artículo en Inglés | MEDLINE | ID: mdl-29083898

RESUMEN

Four new and five known sesquiterpenoids were isolated from the agarwood of Aquilaria malaccensis. Aquilanols A and B (1 and 2) have an unprecedented macrocyclic humulene structure with a bicyclic 7/10 ring system. Compound 2 was obtained as a scalemic mixture that was resolved by HPLC analysis using a chiral column. Their structures were deduced based on spectroscopic data analysis, and the absolute configurations were unambiguously determined by X-ray crystallographic data and ECD spectroscopic analysis. A putative biosynthetic pathway of these sesquiterpenoids is proposed.


Asunto(s)
Inhibidores de la Colinesterasa/aislamiento & purificación , Sesquiterpenos/aislamiento & purificación , Thymelaeaceae/química , Madera/química , Algoritmos , Inhibidores de la Colinesterasa/química , Cromatografía Líquida de Alta Presión , Cristalografía por Rayos X , Enterococcus faecalis/efectos de los fármacos , Escherichia coli/efectos de los fármacos , Klebsiella pneumoniae/efectos de los fármacos , Laos , Pruebas de Sensibilidad Microbiana , Conformación Molecular , Estructura Molecular , Sesquiterpenos Monocíclicos , Resonancia Magnética Nuclear Biomolecular , Salmonella enterica/efectos de los fármacos , Sesquiterpenos/química , Sesquiterpenos/metabolismo , Staphylococcus aureus/efectos de los fármacos , Estereoisomerismo
3.
Opt Express ; 22(21): 25953-64, 2014 Oct 20.
Artículo en Inglés | MEDLINE | ID: mdl-25401629

RESUMEN

We propose a novel structure that includes two compact, simply structured, and lossy waveguides for reducing back reflection in MMI combiners. The preferred lossy waveguide consists of a bend section and a tapered section. Theoretical calculations and 2D FDTD analysis were used to confirm the properties of our proposed structure. Significantly and interestingly, for TE modes, the optimized bend radius is about 7.5 µm and the specific back reflectance depends on taper end width. For TM modes, to achieve a back reflection value smaller than -30 dB, the taper length of 30 µm is desired regardless of bend radius. Moreover, the introduction of the lossy waveguide influences neither the MMI design nor its operation.


Asunto(s)
Luz , Refractometría/instrumentación , Dispersión de Radiación , Silicio/química , Diseño de Equipo
4.
J Ginseng Res ; 38(2): 154-9, 2014 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-24748840

RESUMEN

BACKGROUND: This study was carried out to investigate the effect of the steaming process on chemical constituents, free radical scavenging activity, and antiproliferative effect of Vietnamese ginseng. METHODS: Samples of powdered Vietnamese ginseng were steamed at 120°C for various times and their extracts were subjected to chemical and biological studies. RESULTS: Upon steaming, contents of polar ginsenosides, such as Rb1, Rc, Rd, Re, and Rg1, were rapidly decreased, whereas less polar ginsenosides such as Rg3, Rg5, Rk1, Rk3, and Rh4 were increased as reported previously. However, ocotillol type saponins, which have no glycosyl moiety at the C-20 position, were relatively stable on steaming. The radical scavenging activity was increased continuously up to 20 h of steaming. Similarly, the antiproliferative activity against A549 lung cancer cells was also increased. CONCLUSION: It seems that the antiproliferative activity is closely related to the contents of ginsenoside Rg3, Rg5, and Rk1.

5.
Int J Oncol ; 43(2): 591-9, 2013 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-23708152

RESUMEN

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a promising anticancer agent because its cytotoxicity is selective for tumor cells. Despite promising outcomes in clinical trials using this ligand, sustained clinical responses have been impeded because cancer cells acquire resistance to TRAIL-based therapies. Ginseng, a well-known food product consumed globally, has been reported to reduce fatigue and possess antioxidant and antitumor activities. We explored the sensitizing influence of a formulated red ginseng extract (RGE) on TRAIL-derived cell death in hepatocellular carcinoma (HCC) cell lines and the underlying molecular mechanisms responsible for TRAIL sensitization. We found that the RGE promoted TRAIL-derived apoptosis in HepG2, Huh-7 and Hep3B cell lines. We also found that death receptor 5 expression was induced by the RGE and mediated by C/EBP homologous protein (CHOP). shRNA-induced downregulation of CHOP expression effectively suppressed cell death induced by combined treatment with the RGE and TRAIL in the HepG2 cell line, indicating that RGE-related upregulation of the CHOP protein plays an important role in sensitizing TRAIL-derived apoptosis. In summary, we showed that the RGE sensitized human HCC cell lines to TRAIL-derived cell death and could be utilized as a dietary supplement in combination with cancer treatment.


Asunto(s)
Carcinoma Hepatocelular/metabolismo , Ginsenósidos/farmacología , Neoplasias Hepáticas/metabolismo , Panax/química , Extractos Vegetales/farmacología , Ligando Inductor de Apoptosis Relacionado con TNF/farmacología , Factor de Transcripción CHOP/biosíntesis , Apoptosis/efectos de los fármacos , Línea Celular Tumoral , Regulación hacia Abajo/efectos de los fármacos , Sinergismo Farmacológico , Ginsenósidos/química , Células Hep G2 , Humanos , Extractos Vegetales/química , Interferencia de ARN , ARN Interferente Pequeño , Receptores del Ligando Inductor de Apoptosis Relacionado con TNF/biosíntesis , Receptores del Ligando Inductor de Apoptosis Relacionado con TNF/efectos de los fármacos , Factor de Transcripción CHOP/genética , Regulación hacia Arriba
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