The role of Schottky barrier in the resistive switching of SrTiO3: direct experimental evidence

2015 ◽  
Vol 17 (1) ◽  
pp. 134-137 ◽  
Author(s):  
Xue-Bing Yin ◽  
Zheng-Hua Tan ◽  
Xin Guo
Keyword(s):  
Experimental Evidence ◽  
Schottky Barrier ◽  
Resistive Switching ◽  
Metallic Electrode ◽  
Barrier Heights ◽  
Direct Experimental Evidence

Different Schottky barrier heights are responsible for the different resistance states in the metallic electrode/donor-doped SrTiO3 stack.

Electron Transport Through Epitaxial Metal/Semiconductor Heterostructures

1986 ◽  
Vol 77 ◽  
Author(s):  
A. F. J. Levi ◽  
R. T. Tung ◽  
J. L. Batstone ◽  
J. M. Gibson ◽  
M. Anzlowar ◽  
...  
Keyword(s):  
Electron Transport ◽  
Schottky Barrier ◽  
Semiconductor Heterostructures ◽  
Perfect Single Crystal ◽  
Barrier Heights ◽  
Semiconductor Interfaces ◽  
Semiconductor Contacts ◽  
First Time ◽  
Silicon Heterostructures

ABSTRACTAbrupt, epitaxial silicide/silicon heterostructures may be grown so that, for the first time, the physics of electron transport across near perfect, single crystal, metal/semiconductor interfaces may be probed experimentally. Transport measurements through type-A and -B oriented NiSi2 layers on Si(111) substrates have revealed Schottky barrier heights differing by 140 meV. In this paper we present results of experiments designed to explore the possible role of bulk and interface defects in determining the potential barrier at these near ideal epitaxial metal-semiconductor contacts. We have found little evidence for the presence of defects and the Schottky barrier is insensitive to details of the microscopic interfacial perfection. By contrast we find that both the electrical quality and magnitude of the barrier occurring at the NiSi2 /Si(100) heterojunction are dependent upon details of the microscopic interfacial perfection.

TESTING GOAL-DRIVEN CAPTURE BY THREAT

2019 ◽  
Author(s):  
Chris Robert Harrison Brown
Keyword(s):  
Experimental Evidence ◽  
Attentional Capture ◽  
Critical Role ◽  
Experimental Manipulation ◽  
Contingent Capture ◽  
Top Down ◽  
Affective Stimuli ◽  
Clinical Disorders ◽  
Positive Stimuli

Attention has long been characterised within prominent models as reflecting a competition between goal-driven and stimulus-driven processes. It remains unclear, however, how involuntary attentional capture by affective stimuli, such as threat-laden content, fits into such models. While such effects were traditionally held to reflect stimulus-driven processes, recent research has increasingly implicated a critical role of goal-driven processes. Here we test an alternative goal-driven account of involuntary attentional capture by threat, using an experimental manipulation of goal-driven attention. To this end we combined the classic ‘contingent capture’ and ‘emotion-induced blink’ (EIB) paradigms in an RSVP task with both positive or threatening target search goals. Across six experiments, positive and threat distractors were presented in peripheral, parafoveal, and central locations. Across all distractor locations, we found that involuntary attentional capture by irrelevant threatening distractors could be induced via the adoption of a search goal for a threatening category; adopting a goal for a positive category conversely led to capture only by positive stimuli. Our findings provide direct experimental evidence for a causal role of voluntary goals in involuntary capture by irrelevant threat stimuli, and hence demonstrate the plausibility of a top-down account of this phenomenon. We discuss the implications of these findings in relation to current cognitive models of attention and clinical disorders.

scholarly journals Experimental evidence of pathogenic role of IgG autoantibodies in IgA nephropathy

2021 ◽  
Vol 118 ◽  
pp. 102593
Author(s):  
Zina Moldoveanu ◽  
Hitoshi Suzuki ◽  
Colin Reily ◽  
Kenji Satake ◽  
Lea Novak ◽  
...  
Keyword(s):  
Experimental Evidence ◽  
Iga Nephropathy ◽  
Pathogenic Role

scholarly journals O-GlcNAcylation protein disruption by Thiamet G promotes changes on the GBM U87-MG cells secretome molecular signature

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Maria Cecilia Oliveira-Nunes ◽  
Glaucia Julião ◽  
Aline Menezes ◽  
Fernanda Mariath ◽  
John A. Hanover ◽  
...  
Keyword(s):  
Experimental Evidence ◽  
Critical Role ◽  
Molecular Signature ◽  
Label Free ◽  
Intercellular Signaling ◽  
Tumor Aggressiveness ◽  
Signaling Axis ◽  
Literature Evidence ◽  
Therapeutic Tools

AbstractGlioblastoma (GBM) is a grade IV glioma highly aggressive and refractory to the therapeutic approaches currently in use. O-GlcNAcylation plays a key role for tumor aggressiveness and progression in different types of cancer; however, experimental evidence of its involvement in GBM are still lacking. Here, we show that O-GlcNAcylation plays a critical role in maintaining the composition of the GBM secretome, whereas inhibition of OGA activity disrupts the intercellular signaling via microvesicles. Using a label-free quantitative proteomics methodology, we identified 51 proteins in the GBM secretome whose abundance was significantly altered by activity inhibition of O-GlcNAcase (iOGA). Among these proteins, we observed that proteins related to proteasome activity and to regulation of immune response in the tumor microenvironment were consistently downregulated in GBM cells upon iOGA. While the proteins IGFBP3, IL-6 and HSPA5 were downregulated in GBM iOGA cells, the protein SQSTM1/p62 was exclusively found in GBM cells under iOGA. These findings were in line with literature evidence on the role of p62/IL-6 signaling axis in suppressing tumor aggressiveness and our experimental evidence showing a decrease in radioresistance potential of these cells. Taken together, our findings provide evidence that OGA activity may regulate the p62 and IL-6 abundance in the GBM secretome. We propose that the assessment of tumor status from the main proteins present in its secretome may contribute to the advancement of diagnostic, prognostic and even therapeutic tools to approach this relevant malignancy.

scholarly journals Theoretical Study on the Photo-Oxidation and Photoreduction of an Azetidine Derivative as a Model of DNA Repair

Molecules ◽  
2021 ◽  
Vol 26 (10) ◽  
pp. 2911
Author(s):  
Miriam Navarrete-Miguel ◽  
Antonio Francés-Monerris ◽  
Miguel A. Miranda ◽  
Virginie Lhiaubet-Vallet ◽  
Daniel Roca-Sanjuán
Keyword(s):  
Electron Transfer ◽  
Energy Barrier ◽  
Ring Opening ◽  
Dna Lesions ◽  
Barrier Heights ◽  
Dna Lesion ◽  
Electron Reduction ◽  
The Stability ◽  
Electron Transfer Processes

Photocycloreversion plays a central role in the study of the repair of DNA lesions, reverting them into the original pyrimidine nucleobases. Particularly, among the proposed mechanisms for the repair of DNA (6-4) photoproducts by photolyases, it has been suggested that it takes place through an intermediate characterized by a four-membered heterocyclic oxetane or azetidine ring, whose opening requires the reduction of the fused nucleobases. The specific role of this electron transfer step and its impact on the ring opening energetics remain to be understood. These processes are studied herein by means of quantum-chemical calculations on the two azetidine stereoisomers obtained from photocycloaddition between 6-azauracil and cyclohexene. First, we analyze the efficiency of the electron-transfer processes by computing the redox properties of the azetidine isomers as well as those of a series of aromatic photosensitizers acting as photoreductants and photo-oxidants. We find certain stereodifferentiation favoring oxidation of the cis-isomer, in agreement with previous experimental data. Second, we determine the reaction profiles of the ring-opening mechanism of the cationic, neutral, and anionic systems and assess their feasibility based on their energy barrier heights and the stability of the reactants and products. Results show that oxidation largely decreases the ring-opening energy barrier for both stereoisomers, even though the process is forecast as too slow to be competitive. Conversely, one-electron reduction dramatically facilitates the ring opening of the azetidine heterocycle. Considering the overall quantum-chemistry findings, N,N-dimethylaniline is proposed as an efficient photosensitizer to trigger the photoinduced cycloreversion of the DNA lesion model.

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