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1.
Adv Mater ; : e1905764, 2019 Dec 18.
Artigo em Inglês | MEDLINE | ID: mdl-31850652

RESUMO

Neuromorphic computing consisting of artificial synapses and neural network algorithms provides a promising approach for overcoming the inherent limitations of current computing architecture. Developments in electronic devices that can accurately mimic the synaptic plasticity of biological synapses, have promoted the research boom of neuromorphic computing. It is reported that robust ferroelectric tunnel junctions can be employed to design high-performance electronic synapses. These devices show an excellent memristor function with many reproducible states (≈200) through gradual ferroelectric domain switching. Both short- and long-term plasticity can be emulated by finely tuning the applied pulse parameters in the electronic synapse. The analog conductance switching exhibits high linearity and symmetry with small switching variations. A simulated artificial neural network with supervised learning built from these synaptic devices exhibited high classification accuracy (96.4%) for the Mixed National Institute of Standards and Technology (MNIST) handwritten recognition data set.

2.
Dalton Trans ; 48(46): 17200-17209, 2019 Nov 26.
Artigo em Inglês | MEDLINE | ID: mdl-31686075

RESUMO

Mitochondrial pH is known to be alkaline (near 8.0) and has emerged as a potential factor for mitochondrial function and disorder. Here we investigate two pairs of isomeric phosphorescent Ir(iii) complexes (1-4) that show mitochondrial pH-responsive properties and induce mitochondrial dysfunction during photodynamic therapy. These complexes are designed to function by controlling the protonation of the benzimidazole and carboxyl groups. 1 and 2 exhibit enhanced emission intensity and a blue-shift emission change in response to pH alterations from 6.0 to 8.0. They have ideal pKa values (7.49 for 1 and 7.41 for 2) and show mitochondria-specific phosphorescence staining in situ, thereby allowing the monitoring of mitochondrial pH in live cells. 3 and 4 produce abundant intracellular ROS and exhibit high phototoxicities against cancer cells. Interestingly, these pH-responsive probes can be utilized to monitor the change in mitochondrial pH and mitochondrial damage during photodynamic therapy (PDT), which provides a convenient method for the in situ monitoring of therapeutic effects and the assessment of treatment outcomes.

3.
ACS Appl Mater Interfaces ; 11(46): 43473-43479, 2019 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-31702891

RESUMO

The development of artificial synapses has enabled the establishment of brain-inspired computing systems, which provides a promising approach for overcoming the inherent limitations of current computer systems. The two-terminal memristors that faithfully mimic the function of biological synapses have intensive prospects in the neural network field. Here, we propose a high-performance artificial synapse based on oxide tunnel junctions with oxygen vacancy migration. Both short-term and long-term plasticities are mimicked in one device. The oxygen vacancy migration through oxide ultrathin films is utilized to manipulate long-term plasticity. Essential synaptic functions, such as paired pulse facilitation, post-tetanic potentiation, as well as spike-timing-dependent plasticity, are successfully implemented in one device by finely modifying the shape of the pre- and postsynaptic spikes. Ultralow femtojoule energy consumption comparable to that of the human brain indicates its potential application in efficient neuromorphic computing. Oxide tunnel junctions proposed in this work provide an alternative approach for realizing energy-efficient brain-like chips.

4.
Zootaxa ; 4565(1): zootaxa.4565.1.8, 2019 Mar 07.
Artigo em Inglês | MEDLINE | ID: mdl-31716494

RESUMO

The butterfly tribe Baorini Doherty, 1886 is a large group of skippers. In this study, a total of 8 genera and 41 species of putative members of this tribe, which represent most of the generic diversity and nearly all the species diversity of the group in China, were sequenced for two mitochondrial genes and three nuclear genes (2084 bp). Phylogenetic relationships and subdivision of this tribe were investigated and the status of the genera are discussed. Partitioned maximum likelihood analyses were performed based on the combined dataset. Our results suggest that the data are split into two well-supported clades in the phylogeny tree. This analysis also represents the most complete phylogenetic analysis of the tribe Baorini in China to date, and includes several genera and species that have been previously excluded from published phylogenies of this group.


Assuntos
Borboletas , Animais , Núcleo Celular , China , Evolução Molecular , Genes Mitocondriais , Filogenia , Análise de Sequência de DNA
5.
Free Radic Biol Med ; 141: 67-83, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31153974

RESUMO

Endoplasmic reticulum stress (ERS) has been implicated in obesity-associated cardiac remodeling and dysfunction. Inactive rhomboid protein 2 (iRhom2), also known as Rhbdf2, is an inactive member of the rhomboid intramembrane proteinase family, playing an essential role in regulating inflammation. Nevertheless, the role of ERS-meditated iRhom2 pathway in metabolic stress-induced cardiomyopathy remains unknown. In the study, we showed that 4-PBA, as an essential ERS inhibitor, significantly alleviated high fat diet (HFD)-induced metabolic disorder and cardiac dysfunction in mice. Additionally, lipid deposition in heart tissues was prevented by 4-PBA in HFD-challenged mice. Moreover, 4-PBA blunted the expression of iRhom2, TACE, TNFR2 and phosphorylated NF-κB to prevent HFD-induced expression of inflammatory factors. Further, 4-PBA restrained HFD-triggered oxidative stress by promoting Nrf-2 signaling. Importantly, 4-PBA markedly suppressed cardiac ERS in HFD mice. The anti-inflammation, anti-ERS and anti-oxidant effects of 4-PBA were verified in palmitate (PAL)-incubated macrophages and cardiomyocytes. In addition, promoting ERS could obviously enhance iRhom2 signaling in vitro. Intriguingly, our data demonstrated that PAL-induced iRhom2 up-regulation apparently promoted macrophage to generate inflammatory factors that could promote cardiomyocyte inflammation and lipid accumulation. Finally, interventions by adding fisetin or metformin significantly abrogated metabolic stress-induced cardiomyopathy through the mechanisms mentioned above. In conclusion, this study provided a novel mechanism for metabolic stress-induced cardiomyopathy pathogenesis. Therapeutic strategy to restrain ROS/ERS/iRhom2 signaling pathway could be developed to prevent myocardial inflammation and lipid deposition, consequently alleviating obesity-induced cardiomyopathy.

6.
iScience ; 16: 368-377, 2019 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-31220760

RESUMO

Oxide-based resistive switching devices, including ferroelectric tunnel junctions and resistance random access memory, are promising candidates for the next-generation non-volatile memory technology. In this work, we propose a ferroionic tunnel junction to realize a giant electroresistance. It functions as a ferroelectric tunnel junction at low resistance state and as a Schottky junction at high resistance state, due to interface engineering through the field-induced migration of oxygen vacancies. An extremely large electroresistance with ON/OFF ratios of 5.1×107 at room temperature and 2.1×109 at 10 K is achieved, using an ultrathin BaTiO3-δ layer as the ferroelectric barrier and a semiconducting Nb-doped SrTiO3 substrate as the bottom electrode. The results point toward an appealing way for the design of high-performance resistive switching devices based on ultrathin oxide heterostructures by ionic controlled interface engineering.

7.
Cells ; 8(4)2019 03 29.
Artigo em Inglês | MEDLINE | ID: mdl-30934977

RESUMO

: The butterfly tribe Aeromachini Tutt, 1906 is a large group of skippers. In this study, a total of 10 genera and 45 species of putative members of this tribe, which represent most of the generic diversity and nearly all the species diversity of the group in China, were sequenced for two mitochondrial genes and three nuclear genes (2093 bp). The combined dataset was analyzed with maximum likelihood inference using IQtree. We found strong support for monophyly of Aeromachini from China and support for the most recent accepted species in the tribe. Two paraphyletic genera within Aeromachini are presented and discussed. The divergence time estimates with BEAST and ancestral-area reconstructions with RASP provide a detailed description about the historical biogeography of the Aeromachini from China. The tribe very likely originated from the Hengduan Mountains in the late Ecocene and expanded to the Himalaya Mountains and Central China Regions. A dispersal-vicariance analysis suggests that dispersal events have played essential roles in the distribution of extant species, and geological and climatic changes have been important factors driving current distribution patterns.


Assuntos
Borboletas/classificação , Filogenia , Filogeografia , Animais , Teorema de Bayes , China , Funções Verossimilhança , Fatores de Tempo
8.
Adv Mater ; 31(19): e1900379, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30924206

RESUMO

Hardware implementation of artificial synaptic devices that emulate the functions of biological synapses is inspired by the biological neuromorphic system and has drawn considerable interest. Here, a three-terminal ferrite synaptic device based on a topotactic phase transition between crystalline phases is presented. The electrolyte-gating-controlled topotactic phase transformation between brownmillerite SrFeO2.5 and perovskite SrFeO3- δ is confirmed from the examination of the crystal and electronic structure. A synaptic transistor with electrolyte-gated ferrite films by harnessing gate-controllable multilevel conduction states, which originate from many distinct oxygen-deficient perovskite structures of SrFeOx induced by topotactic phase transformation, is successfully constructed. This three-terminal artificial synapse can mimic important synaptic functions, such as synaptic plasticity and spike-timing-dependent plasticity. Simulations of a neural network consisting of ferrite synaptic transistors indicate that the system offers high classification accuracy. These results provide insight into the potential application of advanced topotactic phase transformation materials for designing artificial synapses with high performance.

9.
Artigo em Inglês | MEDLINE | ID: mdl-30634154

RESUMO

To explore the molecular mechanisms underlying the initial differentiation and formation of papillae in sea cucumbers, the transcriptomes of Apostichopus japonicus pentactulae (without papillae) were compared to those of A. japonicus juveniles (with papillae). From the RNA of the three pentactula libraries and the three juvenile libraries, we obtained 41-46 million raw reads, yielding 39-45 million clean reads. From these, we generated 599,673 transcripts and identified 230,604 unigenes. Across all six transcriptomes, we identified 246,207 single nucleotide polymorphisms (SNPs) and 80,455 single sequence repeats (SSRs). There were more transition SNPs (60.74%) than transversion SNPs (39.26%). The mononucleotide repeat was the most abundant SSR motif. We identified 7965 differentially expressed unigenes (DEGs) in the juveniles and the pentactulae; 2421 DEGs were expressed only in the juveniles, and 1238 were expressed only in the pentactulae. Of all DEGs, 5215 were significantly upregulated and 2750 were significantly downregulated in the juveniles as compared to the pentactulae. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses indicated that the DEGs were primarily enriched in ribosome synthesis, cell proliferation, tight junction formation, collagen fibrillogenesis, and neurogenesis.


Assuntos
Ritmo Circadiano/genética , Crustáceos/fisiologia , Perfilação da Expressão Gênica , Maturidade Sexual/genética , Animais , Proteínas de Artrópodes/genética , Crustáceos/genética , DNA Complementar/genética , Feminino , Sequenciamento de Nucleotídeos em Larga Escala , Reação em Cadeia da Polimerase em Tempo Real
10.
Nanoscale Res Lett ; 14(1): 17, 2019 Jan 09.
Artigo em Inglês | MEDLINE | ID: mdl-30627821

RESUMO

SnSe2 field-effect transistor was fabricated based on exfoliated few-layered SnSe2 flake, and its electrical and photoelectric properties have been investigated in detail. With the help of a drop of de-ionized (DI) water, the SnSe2 FET can achieve an on/off ratio as high as ~ 104 within 1 V bias, which is ever extremely difficult for SnSe2 due to its ultrahigh carrier density (1018/cm3). Moreover, the subthreshold swing and mobility are both improved to ∼ 62 mV/decade and ~ 127 cm2 V-1 s-1 at 300 K, which results from the efficient screening by the liquid dielectric gate. Interestingly, the SnSe2 FET exhibits a gate bias-dependent photoconductivity, in which a competition between the carrier concentration and the mobility under illumination plays a key role in determining the polarity of photoconductivity.

11.
Oncol Rep ; 41(3): 1938-1948, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30569158

RESUMO

Cancer stem­like cells (CSCs) are critical for the initiation, progression, chemoresistance and postsurgical recurrence of liver cancer. They are thought to be novel targets for the treatment of liver cancer, however, efficient agents that target liver cancer stem cells (CSCs) have not been identified. MicroRNAs (miRNAs) are small non­coding RNAs that target the 3'untranslated region (3'UTR) of mRNAs. Their dysregulation has been implicated in several types of cancer including liver cancer, but it still remains unknown if they play a role in targeting liver CSCs. We compared the miRNA profiles between liver cancer samples and adjacent non­tumor tissues using The Cancer Genome Atlas (TCGA) datasets. Several miRNAs including miR­486­5p (miR­486) were found to be significantly downregulated in liver cancer tissues. These differentially expressed miRNAs were screened between CSC­enriched tumor spheres and adherent cells. miR­486 was significantly downregulated in tumor spheres and liver cancer samples. Ectopic expression of miR­486 significantly repressed the self­renewal and invasion of CSCs in vitro and tumorigenesis in vivo. Notably, we found that sirtuin 1 (Sirt1) served as a direct target of miR­486. The high expression of Sirt1 was involved in maintaining the self­renewal and tumorigenic potential of liver CSCs. The results of the present study indicated that the miR­486­Sirt1 axis was involved in suppressing CSC traits and tumor progression.


Assuntos
Carcinoma Hepatocelular/genética , Neoplasias Hepáticas/genética , MicroRNAs/metabolismo , Células-Tronco Neoplásicas/metabolismo , Sirtuína 1/genética , Idoso , Carcinogênese/genética , Carcinoma Hepatocelular/patologia , Carcinoma Hepatocelular/cirurgia , Linhagem Celular Tumoral , Proliferação de Células/genética , Conjuntos de Dados como Assunto , Regulação para Baixo , Feminino , Perfilação da Expressão Gênica , Regulação Neoplásica da Expressão Gênica , Hepatectomia , Humanos , Fígado/patologia , Fígado/cirurgia , Neoplasias Hepáticas/patologia , Neoplasias Hepáticas/cirurgia , Masculino , MicroRNAs/genética , Pessoa de Meia-Idade , Recidiva Local de Neoplasia , Células-Tronco Neoplásicas/patologia , Sirtuína 1/metabolismo , Esferoides Celulares
12.
Free Radic Biol Med ; 130: 542-556, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30465824

RESUMO

An increasing number of studies have shown that air pollution containing particulate matter (PM) ≤ 2.5 µm (PM2.5) plays a significant role in the development of metabolic disorder and other chronic diseases. Inflammation and oxidative stress caused by metabolic syndrome are widely determined to be critical factors in the development of nonalcoholic fatty liver disease (NAFLD) pathogenesis. However, there is no direct evidence of this, and the underlying molecular mechanism is still not fully understood. In this study, we investigated the role of inflammation and oxidative stress caused by prolonged PM2.5 exposure in dyslipidemia-associated chronic hepatic injury, and further determined whether an increase in hepatic inflammation and oxidative stress promoted lipid accumulation in the liver, ultimately increasing the risk of NAFLD. Therefore, we studied changes in indicators of metabolic disorder and in symbolic indices of NAFLD. We confirmed increases in insulin resistance, glucose tolerance, peripheral inflammation and dysarteriotony in PM2.5-induced mice. Oxidative stress and inflammatory response in the liver caused by PM2.5 inhalation contributed to abnormal hepatic function, further promoting lipid accumulation in the liver. Moreover, we observed inhibition of oxidative stress and inflammatory response by pyrrolidine dithiocarbamate (PDTC) and N-acetyl-L-cysteine (NAC) in vitro, suggesting that oxidative stress and inflammatory in liver cells aggravated by PM2.5 contributed to hepatic injury by altering normal lipid metabolism. These results indicate a new goal for preventing and treating air pollution-induced diseases: suppression of oxidative stress and inflammatory response.


Assuntos
Dislipidemias/tratamento farmacológico , Inflamação/tratamento farmacológico , Hepatopatia Gordurosa não Alcoólica/tratamento farmacológico , Estresse Oxidativo/efeitos dos fármacos , Material Particulado/toxicidade , Acetilcisteína/farmacologia , Poluentes Atmosféricos/toxicidade , Animais , Dislipidemias/metabolismo , Dislipidemias/patologia , Hepatócitos/efeitos dos fármacos , Humanos , Inflamação/metabolismo , Inflamação/patologia , Resistência à Insulina/genética , Metabolismo dos Lipídeos/efeitos dos fármacos , Fígado/efeitos dos fármacos , Fígado/metabolismo , Síndrome Metabólica/tratamento farmacológico , Síndrome Metabólica/metabolismo , Síndrome Metabólica/patologia , Camundongos , Hepatopatia Gordurosa não Alcoólica/metabolismo , Hepatopatia Gordurosa não Alcoólica/patologia , Material Particulado/química , Pirrolidinas/farmacologia , Transdução de Sinais/efeitos dos fármacos , Tiocarbamatos/farmacologia
13.
Angew Chem Int Ed Engl ; 58(8): 2350-2354, 2019 Feb 18.
Artigo em Inglês | MEDLINE | ID: mdl-30552796

RESUMO

An organoiridium-albumin bioconjugate (Ir1-HSA) was synthesized by reaction of a pendant maleimide ligand with human serum albumin. The phosphorescence of Ir1-HSA was enhanced significantly compared to parent complex Ir1. The long phosphorescence lifetime and high 1 O2 quantum yield of Ir1-HSA are highly favorable properties for photodynamic therapy. Ir1-HSA mainly accumulated in the nucleus of living cancer cells and showed remarkable photocytotoxicity against a range of cancer cell lines and tumor spheroids (light IC50 ; 0.8-5 µm, photo-cytotoxicity index PI=40-60), while remaining non-toxic to normal cells and normal cell spheroids, even after photo-irradiation. This nucleus-targeting organoiridium-albumin is a strong candidate photosensitizer for anticancer photodynamic therapy.

14.
ACS Appl Mater Interfaces ; 10(50): 43792-43801, 2018 Dec 19.
Artigo em Inglês | MEDLINE | ID: mdl-30474948

RESUMO

Exploring and manipulating domain configurations in ferroelectric thin films are of critical importance for the design and fabrication of ferroelectric heterostructures with a novel functional performance. In this study, BiFeO3 (BFO) ultrathin films with various Bi/Fe ratios from excess Bi to deficient Bi have been grown on (La0.7Sr0.3)MnO3 (LSMO)-covered SrTiO3 substrates by a laser molecular beam epitaxy system. Atomic force microscopy and piezoresponse force microscopy measurements show that both the surface morphology and ferroelectric polarization of the films are relevant to Bi nonstoichiometry. More significantly, a Bi-excess thin film shows an upward (from substrate to film surface) uniform ferroelectric polarization, whereas a Bi-deficient thin film exhibits a downward uniform polarization, which means the as-grown polarization of BFO thin films can be controlled by changing the Bi contents. Atomic-scale structural and chemical characterizations and second-harmonic generation measurements reveal that two different kinds of structural distortions and interface atomic configurations in the BFO/LSMO heterostructures can be induced by the change of Bi nonstoichiometry, leading to the two opposite as-grown ferroelectric polarizations. It has also been revealed that the band gap of BFO thin films can be modulated via Bi nonstoichiometry. These results demonstrate that Bi nonstoichiometry plays a key role on the ferroelectric domain states and physical properties of BFO thin films and also open a new avenue to manipulate the structure and ferroelectric domain states in BFO thin films.

15.
Nanotoxicology ; 12(9): 1045-1067, 2018 11.
Artigo em Inglês | MEDLINE | ID: mdl-30257117

RESUMO

Research suggests that particulate matter (PM2.5) is a predisposing factor for metabolic syndrome-related systemic inflammation and oxidative stress injury. TNF-α as a major pro-inflammatory cytokine was confirmed to participate in various diseases. Inactive rhomboid protein 2 (iRhom2) was recently determined as a necessary regulator for shedding of TNF-α in immune cells. Importantly, kidney-resident macrophages are critical to inflammation-associated chronic renal injury. Podocyte injury can be induced by stimulants and give rise to nephritis, but how iRhom2 contributes to PM2.5-induced renal injury is unclear. Thus, we studied whether PM2.5 causes renal injury and characterized iRhom2 with respect to TNF-α release in mice macrophages and renal tissues in long-term PM2.5-exposed mouse models. After long-term PM2.5 exposures, renal injury was confirmed via inflammatory cytokine, chemokine expression, and reduced antioxidant activity. Patients with kidney-related diseases had increased TNF-α, which may contribute to renal injury. We observed up-regulation of serum creatinine, serum urea nitrogen, kidney injury molecule 1, uric acid, TNF-α, MDA, H2O2, and O2- in PM2.5-treated mice, which was greater than that found in Nrf2-/- mice. Meanwhile, increases in metabolic disorder-associated indicators were involved in PM2.5-induced nephritis. In vitro, kidney-resident macrophages were observed to be critical to renal inflammatory infiltration and function loss via regulation of iRhom2/TACE/TNF-α signaling, and suppression of Nrf2-associated anti-oxidant response. PM2.5 exposure led to renal injury partly by inflammation-mediated podocyte injury. Reduced SOD1, SOD2, Nrf2 activation, and increased XO, NF-κB activity, TACE, iNOS, IL-1ß, TNF-α, IL-6, MIP-1α, Emr-1, MCP-1, and Cxcr4, were also noted. Long-term PM2.5 exposure causes chronic renal injury by up-regulation of iRhom2/TACE/TNF-α axis in kidney-resident macrophages. Overexpression of TNF-α derived from macrophages causes podocyte injury and kidney function loss. Thus, PM2.5 toxicities are related to exposure duration and iRhom2 may be a potential therapeutic renal target.


Assuntos
Poluentes Atmosféricos/toxicidade , Proteínas de Transporte/genética , Rim/metabolismo , Fator 2 Relacionado a NF-E2/deficiência , Material Particulado/toxicidade , Insuficiência Renal Crônica/induzido quimicamente , Animais , Linhagem Celular , Citocinas/metabolismo , Humanos , Inflamação , Rim/imunologia , Rim/patologia , Macrófagos/efeitos dos fármacos , Macrófagos/imunologia , Macrófagos/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Fator 2 Relacionado a NF-E2/genética , Estresse Oxidativo/efeitos dos fármacos , Estresse Oxidativo/genética , Tamanho da Partícula , Insuficiência Renal Crônica/genética , Insuficiência Renal Crônica/imunologia , Insuficiência Renal Crônica/metabolismo
16.
Mol Phylogenet Evol ; 129: 158-170, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-30092356

RESUMO

The maternally inherited obligate bacteria Wolbachia is known for infecting the reproductive tissues of a wide range of arthropods and can contribute to phylogenetically discordant patterns between mtDNA and nDNA. In this study, we tested for an association between mito-nuclear discordance in Polytremis and Wolbachia infection. Six of the 17 species of Polytremis were found to be infected with Wolbachia. Overall, 34% (70/204) of Polytremis specimens were Wolbachia positive and three strains of Wolbachia identified using a wsp marker were further characterized as six strains based on MLST markers. Wolbachia acquisition in Polytremis appears to occur mainly through horizontal transmission rather than codivergence based on comparison of the divergence times of Wolbachia and Polytremis species. At the intraspecific level, one of the Wolbachia infections (wNas1) is associated with reduced mtDNA polymorphism in the infected Polytremis population. At the interspecific level, there is one case of mito-nuclear discordance likely caused by introgression of P. fukia mtDNA into P. nascens driven by another Wolbachia strain (wNas3). Based on an absence of infected males, we suspect that one Wolbachia strain (wNas2) affects sex ratio, but the phenotypic effects of the other strains are unclear. These data reveal a dynamic interaction between Polytremis and Wolbachia endosymbionts affecting patterns of mtDNA variation.


Assuntos
DNA Mitocondrial/genética , Variação Genética , Lepidópteros/genética , Lepidópteros/microbiologia , Wolbachia/fisiologia , Animais , Núcleo Celular/genética , China , Feminino , Geografia , Haplótipos/genética , Funções Verossimilhança , Masculino , Tipagem de Sequências Multilocus , Filogenia , Densidade Demográfica , Fatores de Tempo
17.
Adv Mater ; : e1801548, 2018 Jul 04.
Artigo em Inglês | MEDLINE | ID: mdl-29974526

RESUMO

Considering that the human brain uses ≈1015 synapses to operate, the development of effective artificial synapses is essential to build brain-inspired computing systems. In biological synapses, the voltage-gated ion channels are very important for regulating the action-potential firing. Here, an electrolyte-gated transistor using WO3 with a unique tunnel structure, which can emulate the ionic modulation process of biological synapses, is proposed. The transistor successfully realizes synaptic functions of both short-term and long-term plasticity. Short-term plasticity is mimicked with the help of electrolyte ion dynamics under low electrical bias, whereas the long-term plasticity is realized using proton insertion in WO3 under high electrical bias. This is a new working approach to control the transition from short-term memory to long-term memory using different gate voltage amplitude for artificial synapses. Other essential synaptic behaviors, such as paired pulse facilitation, the depression and potentiation of synaptic weight, as well as spike-timing-dependent plasticity are also implemented in this artificial synapse. These results provide a new recipe for designing synaptic electrolyte-gated transistors through the electrostatic and electrochemical effects.

18.
Adv Healthc Mater ; 7(17): e1800427, 2018 09.
Artigo em Inglês | MEDLINE | ID: mdl-29944201

RESUMO

The mortality rate of acute liver failure significantly increases due to fatal septicemia. Inactive rhomboid protein 2 (iRhom2) is an essential regulator of shedding TNF-α by trafficking with TNF-α converting enzyme (TACE). Fisetin, a flavonoid present in various fruits and plants, possesses anti-oxidative stress and anti-inflammatory activities. Here, multi-combination nanoparticles Fe@Au conjugated with fisetin, iRhom2 small interfering RNA (siRNA), and TNF-α inhibitor (FN) are prepared to examine their effects on fatal septicemia-associated hepatic failure induced by Listeria monocytogenes (LM) in mice and to reveal the underlying mechanisms. After LM infection, upregulation of glutamic-oxalacetic transaminease, glutamic-pyruvic transaminase, alkaline phosphatase, TNF-α, malondialdehyde, H2 O2 , and O2- is observedcompared to FN-treated mice. The iRhom2/TACE/TNF-α signals are enhanced in vivo and in vitro, resulting in oxidative stress, which is especially associated with the activation of kupffer cells and other macrophages. Decrease in Nrf2 activation and increase of inflammation-associated regulators are also noted in vivo and in vitro. Furthermore, overexpression of TNF-α derived from macrophages aggravates hepatic failure. Inversely, the processes above are restored by FN nanoparticles through the regulation of the iRhom2/TACE/TNF-α axis and Nrf2 activation. These findings suggest that FN may be a potential approach to protect against bacterial septicemia-related diseases by targeting iRhom2.


Assuntos
Proteínas de Transporte/metabolismo , Listeria monocytogenes/patogenicidade , Falência Hepática/metabolismo , Falência Hepática/microbiologia , Sepse/metabolismo , Sepse/microbiologia , Proteína ADAM17/metabolismo , Animais , Western Blotting , Proteínas de Transporte/genética , Células Cultivadas , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Estresse Oxidativo/fisiologia , Transdução de Sinais/fisiologia , Fator de Necrose Tumoral alfa/metabolismo
19.
Materials (Basel) ; 11(4)2018 Apr 19.
Artigo em Inglês | MEDLINE | ID: mdl-29671755

RESUMO

A class of linear polarization conversion coding metasurfaces (MSs) based on a metal cut-wire structure is proposed, which can be applied to the reduction properties of radar cross section (RCS). We firstly present a hypothesis based on the principle of planar array theory, and then verify the RCS reduction characteristics using linear polarization conversion coding MSs by simulations and experiments. The simulated results show that in the frequency range of 6⁻14 GHz, the linear polarization conversion ratio reaches a maximum value of 90%, which is in good agreement with the theoretical predictions. For normal incident x- and y-polarized waves, RCS reduction of designed coding MSs 01/01 and 01/10 is essentially more than 10 dB in the above-mentioned frequency range. We prepare and measure the 01/10 coding MS sample, and find that the experimental results in terms of reflectance and RCS reduction are in good agreement with the simulated ones under normal incidence. In addition, under oblique incidence, RCS reduction is suppressed as the angle of incidence increases, but still exhibits RCS reduction effects in a certain frequency range. The designed MS is expected to have valuable potential in applications for stealth field technology.

20.
ACS Appl Mater Interfaces ; 10(12): 10211-10219, 2018 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-29510620

RESUMO

Structure determines material's functionality, and strain tunes the structure. Tuning the coherent epitaxial strain by varying the thickness of the films is a precise route to manipulate the functional properties in the low-dimensional oxide materials. Here, to explore the effects of the coherent epitaxial strain on the properties of SrCoO2.5 thin films, thickness-dependent evolutions of the structural properties and electronic structures were investigated by X-ray diffraction, Raman spectra, optical absorption spectra, scanning transmission electron microscopy (STEM), and first-principles calculations. By increasing the thickness of the SrCoO2.5 films, the c-axis lattice constant decreases, indicating the relaxation of the coherent epitaxial strain. The energy band gap increases and the Raman spectra undergo a substantial softening with the relaxation of the coherent epitaxial strain. From the STEM results, it can be concluded that the strain causes the variation of the oxygen content in the BM-SCO2.5 films, which results in the variation of band gaps with varying the strain. First-principles calculations show that strain-induced changes in bond lengths and angles of the octahedral CoO6 and tetrahedral CoO4 cannot explain the variation band gap. Our findings offer an alternative strategy to manipulate structural and electronic properties by tuning the coherent epitaxial strain in transition-metal oxide thin films.

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