1,430 research outputs found

    Characteristics of the dynamics of breakdown filaments in Al2O3/InGaAs stacks

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    In this paper, the Al2O3/InGaAs interface was studied by X-ray photoelectron spectroscopy (XPS) after a breakdown (BD) event at positive bias applied to the gate contact. The dynamics of the BD event were studied by comparable XPS measurements with different current compliance levels during the BD event. The overall results show that indium atoms from the substrate move towards the oxide by an electro-migration process and oxidize upon arrival following a power law dependence on the current compliance of the BD event. Such a result reveals the physical feature of the breakdown characteristics of III-V based metal-oxide-semiconductor devices.Fil: Palumbo, FĂ©lix Roberto Mario. ComisiĂłn Nacional de EnergĂ­a AtĂłmica; Argentina. Universidad TecnolĂłgica Nacional; Argentina. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas; ArgentinaFil: Shekhter, P.. Technion - Israel Institute of Technology; IsraelFil: Cohen Weinfeld, K.. Technion - Israel Institute of Technology; IsraelFil: Eizenberg, M.. Technion - Israel Institute of Technology; Israe

    Low-energy quantum dynamics of atoms at defects. Interstitial oxygen in silicon

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    The problem of the low-energy highly-anharmonic quantum dynamics of isolated impurities in solids is addressed by using path-integral Monte Carlo simulations. Interstitial oxygen in silicon is studied as a prototypical example showing such a behavior. The assignment of a "geometry" to the defect is discussed. Depending on the potential (or on the impurity mass), there is a "classical" regime, where the maximum probability-density for the oxygen nucleus is at the potential minimum. There is another regime, associated to highly anharmonic potentials, where this is not the case. Both regimes are separated by a sharp transition. Also, the decoupling of the many-nuclei problem into a one-body Hamiltonian to describe the low-energy dynamics is studied. The adiabatic potential obtained from the relaxation of all the other degrees of freedom at each value of the coordinate associated to the low-energy motion, gives the best approximation to the full many-nuclei problem.Comment: RevTeX, 6 pages plus 4 figures (all the figures were not accesible before

    Kinetic Modeling of 1‐G Ethanol Fermentations

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    The most recent rise in demand for bioethanol, due mainly to economic and environmental issues, has required highly productive and efficient processes. In this sense, mathematical models play an important role in the design, optimization, and control of bioreactors for ethanol production. Such bioreactors are generally modeled by a set of first‐order ordinary differential equations, which are derived from mass and energy balances over bioreactors. Complementary equations have also been included to describe fermentation kinetics, based on Monod equation with additional terms accounting for inhibition effects linked to the substrate, products, and biomass. In this chapter, a reasonable number of unstructured kinetic models of 1‐G ethanol fermentations have been compiled and reviewed. Segregated models, as regards the physiological state of the biomass (cell viability), have also been reviewed, and it was found that some of the analyzed kinetic models are also applied to the modeling of second‐generation ethanol production processes

    Investigation of stress induced interface states in Al2O3/InGaAs metal-oxide-semiconductor capacitors

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    Implementation of high-k dielectrics on InGaAs for CMOS technology requires capabilities to predict long-time degradation and the impact of process changes on degradation processes. In this work, the degradation under constant voltage stress of metal gate/Al2O3/InGaAs stacks is studied for n-type and p-type As2 passivated InGaAs substrates. The results show that the degradation for both positive bias and negative bias did not produce Al2O3 oxide traps, while the distribution of interface states increased. In particular, the distribution of interface states, calculated by the distributed impedance equivalent circuit model, increased significantly after positive bias stress regardless of the doping type of the substrate. The injection of carriers from the semiconductor conduction band into the gate dielectric enhanced the generation of interface states but not the generation of oxide traps, suggesting that the interfacial degradation is related primarily to the InGaAs surface and not to the oxide layer.Fil: Palumbo, FĂ©lix Roberto Mario. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas; Argentina. Universidad Tecnologica Nacional; ArgentinaFil: Winter, R.. Technion - Israel Institute of Technology; IsraelFil: Tang, K.. University Of Stanford; Estados UnidosFil: McIntyre, P. C.. University Of Stanford; Estados UnidosFil: Eizenberg, M.. Technion - Israel Institute of Technology; Israe

    Determination of the vertical dimension occlusion – case report

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    Abstract in proceedings of the Fourth International Congress of CiiEM: Health, Well-Being and Ageing in the 21st Century, held at Egas Moniz’ University Campus in Monte de Caparica, Almada, from 3–5 June 2019.This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.info:eu-repo/semantics/publishedVersio

    A biorefinery approach to the biomass of the seaweed Undaria pinnatifida (Harvey Suringar, 1873): obtaining phlorotannins-enriched extracts for wound healing

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    Brown seaweeds are recognized sources of compounds with a wide range of properties and applications. Within these compounds, phlorotannins are known to possess several bioactivities (e.g., antioxidant, anti-inflammatory, and antimicrobial) with potential to improve wound healing. To obtain phlorotannins enriched extracts from Undaria pinnatifida, a biorefinery was set using lowcost industry-friendly methodologies, such as sequential solid–liquid extraction and liquid–liquid extraction. The obtained extracts were screened for their antioxidant and antimicrobial activity against five common wound pathogens and for their anti-inflammatory potential. The ethanolic wash fraction (wE100) had the highest antioxidant activity (114.61 +- 10.04 mmol mg-1 extract by Diphenyl-1-picrylhydrazyl (DPPH) and 6.56 +-1.13mMeq. Fe II mg-1 extract by and Ferric Reducing Antioxidant Power (FRAP)), acting efficiently against Gram-negative (Pseudomonas aeruginosa) and Gram-positive (Staphylococcus aureus) bacteria, and showing a nitric oxide production inhibition over 47% when used at 0.01 ug mL-1. NMR and FTIR chemical characterization suggested that phlorotannins are present. Obtained fraction wE100 proved to be a promising candidate for further inclusion as wound healing agents, while the remaining fractions analyzed are potential sources for other biotechnological applications, giving emphasis to a biorefinery and circular economy framework to add value to this seaweed and the industry.info:eu-repo/semantics/publishedVersio

    Tomato Response to Fusarium spp. Infection under Field Conditions: Study of Potential Genes Involved

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    Tomato is one of the most important horticultural crops in the world and is severely affected by Fusarium diseases. To successfully manage these diseases, new insights on the expression of plant– pathogen interaction genes involved in immunity responses to Fusarium spp. infection are required. The aim of this study was to assess the level of infection of Fusarium spp. in field tomato samples and to evaluate the differential expression of target genes involved in plant–pathogen interactions in groups presenting different infection levels. Our study was able to detect Fusarium spp. in 16 from a total of 20 samples, proving the effectiveness of the primer set designed in the ITS region for its detection, and allowed the identification of two main different species complexes: Fusarium oxysporum and Fusarium incarnatum-equiseti. Results demonstrated that the level of infection positively influenced the expression of the transcription factor WRKY41 and the CBEF (calcium-binding EF hand family protein) genes, involved in plant innate resistance to pathogens. To the best of our knowledge, this is the first time that the expression of tomato defense-related gene expression is studied in response to Fusarium infection under natural field conditions. We highlight the importance of these studies for the identification of candidate genes to incorporate new sources of resistance in tomato and achieve sustainable plant disease management.This research was supported by projects “Development of a new virus-based vector to control TSWV in tomato plants” with the references ALT20-03-0145-FEDER-028266 and PTDC/ASP-PLA/28266/2017, and “Control of olive anthracnose through gene silencing and gene ex- pression using a plant virus vector” with the references ALT20-03-0145-FEDER-028263 and PTDC/ASP- PLA/28263/2017, both projects co-financed by the European Union through the European Regional Development Fund, under the ALENTEJO 2020 (Regional Operational Program of the Alentejo), ALGARVE 2020 (Regional Operational Program of the Algarve) and through the Foundation for Science and Technology (FCT), in its national component. M.P. was supported by Portuguese National Funds through FCT/MCTES, under the PhD scholarship SFRH/BD/145321/2019, co-financed by the European Social Fund through the Regional Operational Program of the Alentejo. J.A.R. was supported by Portuguese National Funds through Project ALT20-03-0246-FEDER-000056, “BIOPRO- TOMATE: Bioproteção do tomateiro contra a fusariose—impacto das práticas agronómicas”, under scholarship BI_MESTRE_Uevora_CER_BIOPROTOMATE, co-financed by the European Regional Development Fund through Regional Operational Program Alentejo 2020

    Defense Strategies: The Role of Transcription Factors in Tomato–Pathogen Interaction

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    Tomato, one of the most cultivated and economically important vegetable crops throughout the world, is affected by a panoply of different pathogens that reduce yield and affect product quality. The study of tomato–pathogen system arises as an ideal system for better understanding the molecular mechanisms underlying disease resistance, offering an opportunity of improving yield and quality of the products. Among several genes already identified in tomato response to pathogens, we highlight those encoding the transcription factors (TFs). TFs act as transcriptional activators or repressors of gene expression and are involved in large-scale biological phenomena. They are key regulators of central components of plant innate immune system and basal defense in diverse biological processes, including defense responses to pathogens. Here, we present an overview of recent studies of tomato TFs regarding defense responses to biotic stresses. Hence, we focus on different families of TFs, selected for their abundance, importance, and availability of functionally well-characterized members in response to pathogen attack. Tomato TFs’ roles and possibilities related to their use for engineering pathogen resistance in tomato are presented. With this review, we intend to provide new insights into the regulation of tomato defense mechanisms against invading pathogens in view of plant breeding.This work was funded by the projects “Development of a new virus-based vector to control TSWV in tomato plants” with the references ALT20-03-0145-FEDER-028266 and PTDC/ASP-PLA/28266/2017, and “Control of olive anthracnose through gene silencing and gene expression using a plant virus vector” with the references ALT20-03-0145-FEDER-028263 and PTDC/ASP-PLA/28263/2017, co-financed by the European Union through the European Regional Development Fund, under the ALENTEJO 2020 (Regional Operational Program of the Alentejo), ALGARVE 2020 (Regional Operational Program of the Algarve) and through the Foundation for Science and Technology (FCT), in its national component. M.P. was supported by Portuguese National Funds through FCT/MCTES, under the PhD scholarship SFRH/BD/145321/2019, co-financed by the European Social Fund through the Regional Operational Program of the Alentejo. This work was also supported by National Funds through FCT under the Project UIDB/05183/2020
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